[Lldb-commits] [clang] [lldb] [Clang] Introduce OverflowBehaviorType for fine-grained overflow control (PR #148914)
Justin Stitt via lldb-commits
lldb-commits at lists.llvm.org
Tue Sep 9 10:46:48 PDT 2025
https://github.com/JustinStitt updated https://github.com/llvm/llvm-project/pull/148914
>From 2fe931694d12fdabd2ed7c21f751c33005f5aa47 Mon Sep 17 00:00:00 2001
From: Justin Stitt <justinstitt at google.com>
Date: Mon, 14 Jul 2025 17:30:14 -0700
Subject: [PATCH 1/2] [Clang] implement OverflowBehaviorTypes
Signed-off-by: Justin Stitt <justinstitt at google.com>
---
clang/docs/OverflowBehaviorTypes.rst | 603 ++++++++++++++++++
clang/docs/ReleaseNotes.rst | 20 +
clang/docs/SanitizerSpecialCaseList.rst | 34 +
clang/docs/UndefinedBehaviorSanitizer.rst | 36 ++
clang/docs/index.rst | 1 +
clang/include/clang/AST/ASTContext.h | 20 +
clang/include/clang/AST/ASTNodeTraverser.h | 3 +
clang/include/clang/AST/PropertiesBase.td | 2 +
clang/include/clang/AST/RecursiveASTVisitor.h | 6 +
clang/include/clang/AST/TypeBase.h | 61 +-
clang/include/clang/AST/TypeLoc.h | 28 +
clang/include/clang/AST/TypeProperties.td | 13 +
clang/include/clang/Basic/Attr.td | 7 +
clang/include/clang/Basic/DiagnosticGroups.td | 55 +-
.../clang/Basic/DiagnosticSemaKinds.td | 45 ++
clang/include/clang/Basic/LangOptions.def | 2 +
clang/include/clang/Basic/LangOptions.h | 19 +
clang/include/clang/Basic/TypeNodes.td | 1 +
clang/include/clang/Driver/Options.td | 6 +
clang/include/clang/Sema/Sema.h | 26 +
.../clang/Serialization/TypeBitCodes.def | 1 +
clang/lib/AST/ASTContext.cpp | 184 +++++-
clang/lib/AST/ASTImporter.cpp | 12 +
clang/lib/AST/ASTStructuralEquivalence.cpp | 7 +
clang/lib/AST/ExprConstant.cpp | 6 +-
clang/lib/AST/FormatString.cpp | 3 +
clang/lib/AST/ItaniumMangle.cpp | 12 +
clang/lib/AST/MicrosoftMangle.cpp | 18 +
clang/lib/AST/Type.cpp | 78 ++-
clang/lib/AST/TypeLoc.cpp | 8 +
clang/lib/AST/TypePrinter.cpp | 22 +
clang/lib/CodeGen/CGDebugInfo.cpp | 7 +
clang/lib/CodeGen/CGDebugInfo.h | 1 +
clang/lib/CodeGen/CGExprScalar.cpp | 267 ++++----
clang/lib/CodeGen/CodeGenFunction.cpp | 2 +
clang/lib/CodeGen/CodeGenTypes.cpp | 4 +
clang/lib/CodeGen/ItaniumCXXABI.cpp | 4 +
clang/lib/Driver/ToolChains/Clang.cpp | 3 +
clang/lib/Sema/SemaChecking.cpp | 54 ++
clang/lib/Sema/SemaDecl.cpp | 4 +
clang/lib/Sema/SemaExpr.cpp | 103 ++-
clang/lib/Sema/SemaInit.cpp | 10 +
clang/lib/Sema/SemaLookup.cpp | 2 +
clang/lib/Sema/SemaOverload.cpp | 107 +++-
clang/lib/Sema/SemaTemplate.cpp | 5 +
clang/lib/Sema/SemaTemplateDeduction.cpp | 2 +
clang/lib/Sema/SemaType.cpp | 102 +++
clang/lib/Sema/TreeTransform.h | 21 +
clang/lib/Serialization/ASTReader.cpp | 4 +
clang/lib/Serialization/ASTWriter.cpp | 4 +
.../CodeGen/mangle-ms-overflow-behavior.cpp | 12 +
.../overflow-behavior-types-extensions.c | 50 ++
.../overflow-behavior-types-operators.cpp | 70 ++
.../overflow-behavior-types-promotions.cpp | 50 ++
.../CodeGen/overflow-behavior-types-scl.c | 43 ++
clang/test/CodeGen/overflow-behavior-types.c | 148 +++++
.../test/CodeGen/overflow-behavior-types.cpp | 49 ++
...a-attribute-supported-attributes-list.test | 1 +
.../Sema/attr-overflow-behavior-constexpr.cpp | 43 ++
.../attr-overflow-behavior-format-strings.c | 93 +++
clang/test/Sema/attr-overflow-behavior-off.c | 3 +
.../Sema/attr-overflow-behavior-templates.cpp | 72 +++
clang/test/Sema/attr-overflow-behavior.c | 196 ++++++
clang/test/Sema/attr-overflow-behavior.cpp | 145 +++++
clang/test/SemaCXX/sugar-common-types.cpp | 41 +-
clang/tools/libclang/CIndex.cpp | 4 +
66 files changed, 2909 insertions(+), 156 deletions(-)
create mode 100644 clang/docs/OverflowBehaviorTypes.rst
create mode 100644 clang/test/CodeGen/mangle-ms-overflow-behavior.cpp
create mode 100644 clang/test/CodeGen/overflow-behavior-types-extensions.c
create mode 100644 clang/test/CodeGen/overflow-behavior-types-operators.cpp
create mode 100644 clang/test/CodeGen/overflow-behavior-types-promotions.cpp
create mode 100644 clang/test/CodeGen/overflow-behavior-types-scl.c
create mode 100644 clang/test/CodeGen/overflow-behavior-types.c
create mode 100644 clang/test/CodeGen/overflow-behavior-types.cpp
create mode 100644 clang/test/Sema/attr-overflow-behavior-constexpr.cpp
create mode 100644 clang/test/Sema/attr-overflow-behavior-format-strings.c
create mode 100644 clang/test/Sema/attr-overflow-behavior-off.c
create mode 100644 clang/test/Sema/attr-overflow-behavior-templates.cpp
create mode 100644 clang/test/Sema/attr-overflow-behavior.c
create mode 100644 clang/test/Sema/attr-overflow-behavior.cpp
diff --git a/clang/docs/OverflowBehaviorTypes.rst b/clang/docs/OverflowBehaviorTypes.rst
new file mode 100644
index 0000000000000..5389e5663505d
--- /dev/null
+++ b/clang/docs/OverflowBehaviorTypes.rst
@@ -0,0 +1,603 @@
+=====================
+OverflowBehaviorTypes
+=====================
+
+.. contents::
+ :local:
+
+Introduction
+============
+
+Clang provides a type attribute that allows developers to have fine-grained control
+over the overflow behavior of integer types. The ``overflow_behavior``
+attribute can be used to specify how arithmetic operations on a given integer
+type should behave upon overflow. This is particularly useful for projects that
+need to balance performance and safety, allowing developers to enable or
+disable overflow checks for specific types.
+
+The attribute can be enabled using the compiler option
+``-foverflow-behavior-types``.
+
+The attribute syntax is as follows:
+
+.. code-block:: c++
+
+ __attribute__((overflow_behavior(behavior)))
+
+Where ``behavior`` can be one of the following:
+
+* ``wrap``: Specifies that arithmetic operations on the integer type should
+ wrap on overflow. This is equivalent to the behavior of ``-fwrapv``, but it
+ applies only to the attributed type and may be used with both signed and
+ unsigned types. When this is enabled, UBSan's integer overflow and integer
+ truncation checks (``signed-integer-overflow``,
+ ``unsigned-integer-overflow``, ``implicit-signed-integer-truncation``, and
+ ``implicit-unsigned-integer-truncation``) are suppressed for the attributed
+ type.
+
+* ``no_wrap``: Specifies that arithmetic operations on the integer type should
+ be checked for overflow. When using the ``signed-integer-overflow`` sanitizer
+ or when using ``-ftrapv`` alongside a signed type, this is the default
+ behavior. Using this, one may enforce overflow checks for a type even when
+ ``-fwrapv`` is enabled globally.
+
+This attribute can be applied to ``typedef`` declarations and to integer types directly.
+
+Arithmetic operations containing one or more overflow behavior types may have
+result types that do not match standard integer promotion rules. The
+characteristics of result types across all scenarios are described under `Promotion Rules`_.
+
+Examples
+========
+
+Here is an example of how to use the ``overflow_behavior`` attribute with a ``typedef``:
+
+.. code-block:: c++
+
+ typedef unsigned int __attribute__((overflow_behavior(no_wrap))) non_wrapping_uint;
+
+ non_wrapping_uint add_one(non_wrapping_uint a) {
+ return a + 1; // Overflow is checked for this operation.
+ }
+
+Here is an example of how to use the ``overflow_behavior`` attribute with a type directly:
+
+.. code-block:: c++
+
+ int mul_alot(int n) {
+ int __attribute__((overflow_behavior(wrap))) a = n;
+ return a * 1337; // Potential overflow is not checked and is well-defined
+ }
+
+"Well-defined" overflow is consistent with two's complement wrap-around
+semantics and won't be removed via eager compiler optimizations (like some
+undefined behavior might).
+
+Promotion Rules
+===============
+
+The promotion rules for overflow behavior types are designed to preserve the
+specified overflow behavior throughout an arithmetic expression. They differ
+from standard C/C++ integer promotions but in a predictable way, similar to
+how ``_Complex`` and ``_BitInt`` have their own promotion rules.
+
+The resulting type characteristics for overflow behavior types (OBTs) across a
+variety of scenarios is detailed below.
+
+* **OBT and Standard Integer Type**: In an operation involving an overflow
+ behavior type (OBT) and a standard integer type, the result will have the
+ type of the OBT, including its overflow behavior, sign, and bit-width. The
+ standard integer type is implicitly converted to match the OBT.
+
+ .. code-block:: c++
+
+ typedef char __attribute__((overflow_behavior(no_wrap))) no_wrap_char;
+ no_wrap_char c;
+ unsigned long ul;
+ auto result = c + ul; // result is no_wrap_char
+
+* **Two OBTs of the Same Kind**: When an operation involves two OBTs of the
+ same kind (e.g., both ``wrap``), the result will have the larger of the two
+ bit-widths. If the bit-widths are the same, an unsigned type is favored over
+ a signed one.
+
+ .. code-block:: c++
+
+ typedef unsigned char __attribute__((overflow_behavior(wrap))) u8_wrap;
+ typedef unsigned short __attribute__((overflow_behavior(wrap))) u16_wrap;
+ u8_wrap a;
+ u16_wrap b;
+ auto result = a + b; // result is u16_wrap
+
+* **Two OBTs of Different Kinds**: In an operation between a ``wrap`` and a
+ ``no_wrap`` type, a ``no_wrap`` type is always produced. Clang will bias the
+ ``no_wrap`` type as converting from ``wrap`` to ``no_wrap`` is not as
+ troubling as converting from ``no_wrap`` to ``wrap``, in most cases.
+ Therefore, the resulting type matches the bit-width, sign and behavior of the
+ ``no_wrap`` type. It is recommended to avoid such operations, as Clang may
+ emit a warning for these cases in the future.
+
+
+.. list-table:: Promotion Rules Summary
+ :widths: 30 70
+ :header-rows: 1
+
+ * - Operation Type
+ - Result Type
+ * - OBT + Standard Integer
+ - OBT type (preserves overflow behavior, sign, and bit-width)
+ * - Same Kind OBTs (both ``wrap`` or both ``no_wrap``)
+ - Larger bit-width; unsigned favored if same width
+ * - Different Kind OBTs (``wrap`` + ``no_wrap``)
+ - ``no_wrap`` type (matches ``no_wrap`` operand's characteristics)
+
+Following traditional C promotion rules for integer types often results in
+modified bit boundaries for types. Since overflow behavior types aim to make
+guarantees about the overflow behavior of a type, it is important to maintain
+consistent bit-widths across arithmetic expressions containing overflow
+behavior types. Therefore, we have the above promotion rules as they preserve
+bit-widths and overflow resolution behaviors during promotions.
+
+Practical example of the promotion rules and how they differ from traditional C
+promotion rules:
+
+.. code-block:: c++
+
+ unsigned short __attribute__((overflow_behavior(no_wrap))) a = 0; // u16 __no_wrap
+
+ // Normally, arithmetic that is less-than-int is promoted to at least int.
+ // Following traditional C promotion rules: u16 + s32 results in s32
+ // However, since `a` is an OBT, our special promotion rules apply: u16 __no_wrap + s32 results in u16 __no_wrap
+
+ a + 1; // result is short __attribute__((overflow_behavior(no_wrap)))
+
+Conversion Semantics
+====================
+
+Overflow behavior types are implicitly convertible to and from built-in
+integral types with specific semantics for warnings and constant evaluation.
+
+Constant Conversion Warnings
+----------------------------
+
+When a constant expression is converted to a narrower type that would cause
+value truncation, the ``-Wconstant-conversion`` warning behavior depends on
+the **destination type**:
+
+* **Destination is wrapping type**
+ (``__attribute__((overflow_behavior(wrap)))``): No warning is issued
+ regardless of compiler flags because truncation with wrapping behavior is
+ expected and well-defined.
+
+* **Destination is non-wrapping or standard type**: Warnings are issued based
+ on compiler flags.
+
+.. code-block:: c++
+
+ #define __wrap __attribute__((overflow_behavior(wrap)))
+ #define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+ // Examples of constant conversion behavior
+ short x1 = (int __wrap)100000; // Warning: truncation to standard type
+ short __wrap x2 = (int)100000; // No warning: wrapping destination (also no UBSan truncation warning)
+ short __no_wrap x3 = (int)100000; // Warning: truncation with overflow check
+ short x4 = (int __no_wrap)100000; // Warning: truncation to standard type
+
+This rule ensures that explicit use of wrapping types suppresses warnings
+only when the destination is intended to wrap, while preserving warnings
+for potentially unintended truncation to standard or non-wrapping types.
+
+See below for more details specifically regarding implicit conversions due to
+assignment.
+
+Implicit Conversions Due to Assignment
+--------------------------------------
+
+Like with the basic integral types in C and C++, types on the right-hand side
+of an assignment may be implicitly converted to match the left-hand side.
+
+All built-in integral types can be implicitly converted to an overflow behavior
+version.
+
+.. code-block:: c++
+
+ char x = 1;
+ int __attribute__((overflow_behavior(wrap))) a = x; // x converted to int __attribute__((overflow_behavior(wrap)))
+
+When assigning one overflow behavior type to another, the left-hand side's type
+is always used - just like with traditional integer types.
+
+.. code-block:: c++
+
+ long __attribute__((overflow_behavior(wrap))) x = __LONG_MAX__;
+ int __attribute__((overflow_behavior(no_wrap))) a = x; // x converted to int __attribute__((overflow_behavior(no_wrap)))
+
+For the purposes of truncation warnings from UBSAN or ``-Wconversion``, the
+left-hand side's overflow behavior determines the instrumentation and
+reporting. For example, the code above would cause a ``-Wshorten-64-to-32``
+warning. Swapping the overflow behavior kinds in the above example would not
+result in a warning diagnostic as the left-hand side would be ``wraps`` which
+silences any truncation warnings.
+
+C++ Narrowing Conversions
+-------------------------
+
+In C++, overflow behavior types also affect narrowing conversion diagnostics
+in brace initialization. When a constant expression would cause a narrowing
+conversion, the behavior depends on the **destination type**:
+
+* **Destination is wrapping type**
+ (``__attribute__((overflow_behavior(wrap)))``): No C++ narrowing conversion
+ error is issued, allowing the initialization to succeed even in ``constexpr``
+ contexts.
+
+* **Destination is non-wrapping or standard type**: C++ narrowing conversion
+ error is issued as normal.
+
+.. code-block:: c++
+
+ #define __wrap __attribute__((overflow_behavior(wrap)))
+ #define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+ // C++ narrowing conversion behavior
+ constexpr short __wrap x1 = {(int)100000}; // OK: wrapping destination
+ constexpr short x2 = {(int)100000}; // Error: standard destination
+ constexpr short __no_wrap x3 = {(int)100000}; // Error: non-wrapping destination
+
+This allows ``wrap`` types to be used seamlessly in ``constexpr`` contexts
+where truncation is intentional and expected.
+
+Note that truncation itself is a form of overflow behavior - when a value
+is too large to fit in the destination type, the high-order bits are
+discarded, which is the wrapping behavior that ``wrap`` types are
+designed to handle predictably.
+
+UBSan Truncation Checks
+------------------------
+
+The destination type also determines UBSan's
+``implicit-signed-integer-truncation`` and
+``implicit-unsigned-integer-truncation`` behavior. Conversions to
+``__attribute__((overflow_behavior(wrap)))`` destinations suppress these UBSan
+checks since truncation is expected and well-defined for wrapping types.
+
+C++ Overload Resolution
+-----------------------
+
+For the purposes of C++ overload set formation, promotions or conversions to
+and from overflow behavior types are of the same rank as normal integer
+promotions and conversions. These rules have implications during overload
+candidate selection which may lead to unexpected but correct ambiguity errors.
+
+The example below shows potential ambiguity as matching just the underlying
+type of an OBT parameter is not enough to precisely pick an overload candidate.
+
+.. code-block:: c++
+
+ void foo(__attribute__((overflow_behavior(no_wrap))) int a);
+ void foo(short a);
+
+ void bar(int a) {
+ foo(a); // call to 'foo' is ambiguous
+ }
+
+Most integral types can be implicitly converted to match OBT parameter types
+and this can be done unambiguously in certain cases. Especially, when all other
+candidates are not implicitly convertible.
+
+.. code-block:: c++
+
+ void foo(__attribute__((overflow_behavior(no_wrap))) int a);
+ void foo(char *a);
+
+ void bar(int a) {
+ foo(a); // picks foo(__no_wrap int)
+ }
+
+
+Overflow behavior types with differing kinds may also create ambiguity in
+certain contexts.
+
+.. code-block:: c++
+
+ void foo(__attribute__((overflow_behavior(no_wrap))) int a);
+ void foo(__attribute__((overflow_behavior(wrap))) int a);
+
+ void bar(int a) {
+ foo(a); // call to 'foo' is ambiguous
+ }
+
+Overflow behavior types may also be used as template parameters and used within
+C ``_Generic`` expressions.
+
+C _Generic Expressions
+----------------------
+
+Overflow behavior types may be used within C ``_Generic`` expressions.
+
+Overflow behavior types do not match against their underlying types within C
+``_Generic`` expressions. This means that an OBT will not be considered
+equivalent to its base type for generic selection purposes. OBTs will match
+against exact types considering bitwidth, signedness and overflow
+behavior kind.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrap_int;
+
+ int foo(wrap_int x) {
+ return _Generic(x, int: 1, char: 2, default: 3); // returns 3
+ }
+
+ int bar(wrap_int x) {
+ return _Generic(x, wrap_int: 1, int: 2, default: 3); // returns 1
+ }
+
+
+C++ Template Specializations
+-----------------------------
+
+Like with ``_Generic``, each OBT is treated as a distinct type for template
+specialization purposes, enabling precise type-based template selection.
+
+.. code-block:: c++
+
+ template<typename T>
+ struct TypeProcessor {
+ static constexpr int value = 0; // default case
+ };
+
+ template<>
+ struct TypeProcessor<int> {
+ static constexpr int value = 1; // int specialization
+ };
+
+ template<>
+ struct TypeProcessor<int __attribute__((overflow_behavior(wrap)))> {
+ static constexpr int value = 2; // __wrap int specialization
+ };
+
+ template<>
+ struct TypeProcessor<int __attribute__((overflow_behavior(no_wrap)))> {
+ static constexpr int value = 3; // __no_wrap int specialization
+ };
+
+When no exact template specialization exists for an OBT, it falls back to the
+default template rather than matching the underlying type specialization,
+maintaining type safety and avoiding unexpected behavior.
+
+Interaction with Command-Line Flags and Sanitizer Special Case Lists
+====================================================================
+
+The ``overflow_behavior`` attribute interacts with sanitizers, ``-ftrapv``,
+``-fwrapv``, and Sanitizer Special Case Lists (SSCL) by wholly overriding these
+global flags. The following table summarizes the interactions:
+
+.. list-table:: Overflow Behavior Precedence
+ :widths: 15 15 15 15 20 15
+ :header-rows: 1
+
+ * - Behavior
+ - Default(No Flags)
+ - -ftrapv
+ - -fwrapv
+ - Sanitizers
+ - SSCL
+ * - ``overflow_behavior(wrap)``
+ - Wraps
+ - Wraps
+ - Wraps
+ - No report
+ - Overrides SSCL
+ * - ``overflow_behavior(no_wrap)``
+ - Traps
+ - Traps
+ - Traps
+ - Reports
+ - Overrides SSCL
+
+It is important to note the distinction between signed and unsigned types. For
+unsigned integers, which wrap on overflow by default, ``overflow_behavior(no_wrap)``
+is particularly useful for enabling overflow checks. For signed integers, whose
+overflow behavior is undefined by default, ``overflow_behavior(wrap)`` provides
+a guaranteed wrapping behavior.
+
+The ``overflow_behavior`` attribute can be used to override the behavior of
+entries from a :doc:`SanitizerSpecialCaseList`. This is useful for allowlisting
+specific types into overflow instrumentation.
+
+Diagnostics
+===========
+
+Clang provides diagnostics to help developers manage overflow behavior types.
+
+-Woverflow-behavior-conversion
+------------------------------
+
+This warning group is issued when an overflow behavior type is implicitly converted
+to a standard integer type, which may lead to the loss of the specified
+overflow behavior.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrapping_int;
+
+ void some_function(int);
+
+ void another_function(wrapping_int w) {
+ some_function(w); // warning: implicit conversion from 'wrapping_int' to
+ // 'int' discards overflow behavior
+ }
+
+To fix this, you can explicitly cast the overflow behavior type to a standard
+integer type.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrapping_int;
+
+ void some_function(int);
+
+ void another_function(wrapping_int w) {
+ some_function(static_cast<int>(w)); // OK
+ }
+
+This warning group includes
+``-Wimplicit-overflow-behavior-conversion``, which includes
+``-Wimplicit-overflow-behavior-conversion-assignment`` and
+``-Wimplicit-overflow-behavior-conversion-pedantic``.
+
+.. note::
+ ``-Woverflow-behavior-conversion`` is implied by ``-Wconversion``.
+
+-Wimplicit-overflow-behavior-conversion
+---------------------------------------
+
+This warning is issued when an overflow behavior type is implicitly converted
+to a standard integer type as part of most conversions, which may lead to the
+loss of the specified overflow behavior. This is the main warning in the
+``-Woverflow-behavior-conversion`` group.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrapping_int;
+
+ void some_function() {
+ wrapping_int w = 1;
+ int i = w; // warning: implicit conversion from 'wrapping_int' to 'int'
+ // during assignment discards overflow behavior
+ // [-Wimplicit-overflow-behavior-conversion]
+ }
+
+Here's another example showing function parameter conversion with a ``no_wrap`` type:
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(no_wrap))) safe_int;
+
+ void bar(int x); // Function expects standard int
+
+ void foo() {
+ safe_int s = 42;
+ bar(s); // warning: implicit conversion from 'safe_int' to 'int'
+ // discards overflow behavior
+ // [-Wimplicit-overflow-behavior-conversion]
+ }
+
+To fix this, you can explicitly cast the overflow behavior type to a standard
+integer type.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrapping_int;
+ typedef int __attribute__((overflow_behavior(no_wrap))) safe_int;
+
+ void some_function() {
+ wrapping_int w = 1;
+ int i = static_cast<int>(w); // OK
+ int j = (int)w; // C-style OK
+ }
+
+ void bar(int x);
+
+ void foo() {
+ safe_int s = 42;
+ bar(static_cast<int>(s)); // OK
+ }
+
+
+-Wimplicit-overflow-behavior-conversion-assignment
+-------------------------------------------------
+
+This warning is issued specifically when an overflow behavior type is implicitly
+converted to a standard integer type during assignment operations. This is a
+subset of the more general ``-Wimplicit-overflow-behavior-conversion`` warning,
+allowing developers to control assignment-specific warnings separately.
+
+.. code-block:: c++
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrapping_int;
+
+ void some_function() {
+ wrapping_int w = 1;
+ int i = w; // warning: implicit conversion from 'wrapping_int' to 'int'
+ // during assignment discards overflow behavior
+ // [-Wimplicit-overflow-behavior-conversion-assignment]
+ }
+
+This diagnostic can be controlled independently, allowing projects to suppress
+assignment-related warnings while still receiving warnings for other types of
+implicit conversions (such as function parameter passing).
+
+-Wimplicit-overflow-behavior-conversion-pedantic
+------------------------------------------------
+
+A less severe version of the warning, ``-Wimplicit-overflow-behavior-conversion-pedantic``,
+is issued for implicit conversions from an unsigned wrapping type to a standard
+unsigned integer type. This is considered less problematic because both types
+have well-defined wrapping behavior, but the conversion still discards the
+explicit ``overflow_behavior`` attribute.
+
+.. code-block:: c++
+
+ typedef unsigned int __attribute__((overflow_behavior(wrap))) wrapping_uint;
+
+ void some_function(unsigned int);
+
+ void another_function(wrapping_uint w) {
+ some_function(w); // warning: implicit conversion from 'wrapping_uint' to
+ // 'unsigned int' discards overflow behavior
+ // [-Wimplicit-overflow-behavior-conversion-pedantic]
+ }
+
+Format String Functions
+=======================
+
+When overflow behavior types are used with format string functions (printf-family
+functions like ``printf``, ``fprintf``, ``sprintf``, etc., and scanf-family
+functions like ``scanf``, ``fscanf``, ``sscanf``, etc.), they are treated based
+on their underlying integer types for format specifier compatibility checking.
+More generally, overflow behavior types are ABI-compatible with their underlying
+types when passed to any varargs function.
+
+.. code-block:: c++
+
+ #include <cstdio>
+
+ typedef int __attribute__((overflow_behavior(wrap))) wrap_int;
+ typedef unsigned int __attribute__((overflow_behavior(no_wrap))) nowrap_uint;
+
+ void example() {
+ wrap_int wi = 42;
+ nowrap_uint su = 100;
+
+ scanf("%d\n", &wi); // OK: &wi treated as int* for %d
+ printf("%d\n", wi); // OK: wi treated as int for %d
+ printf("%u\n", su); // OK: su treated as unsigned int for %u
+ printf("%s\n", wi); // Error: int incompatible with %s (same as regular int)
+ }
+
+This behavior ensures that overflow behavior types work seamlessly with existing
+format string functions without requiring special format specifiers, while
+still maintaining their overflow behavior semantics in arithmetic operations.
+
+The format string checker uses the underlying type to determine compatibility,
+so ``int __attribute__((overflow_behavior(wrap)))`` is fully compatible with
+``%d``, ``%i``, ``%x``, etc., just like a regular ``int`` would be.
+
+-Woverflow-behavior-attribute-ignored
+-------------------------------------
+
+This warning is issued when the ``overflow_behavior`` attribute is applied to
+a type that is not an integer type.
+
+.. code-block:: c++
+
+ typedef float __attribute__((overflow_behavior(wrap))) wrapping_float;
+ // warning: 'overflow_behavior' attribute only applies to integer types;
+ // attribute is ignored [-Woverflow-behavior-attribute-ignored]
+
+ typedef struct S { int i; } __attribute__((overflow_behavior(wrap))) S_t;
+ // warning: 'overflow_behavior' attribute only applies to integer types;
+ // attribute is ignored [-Woverflow-behavior-attribute-ignored]
+
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a20b1ab298f9c..a6db72b350e23 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -218,6 +218,22 @@ Lanai Support
^^^^^^^^^^^^^^
- The option ``-mcmodel={small,medium,large}`` is supported again.
+- New option ``-Wundef-true`` added and enabled by default to warn when `true` is used in the C preprocessor without being defined before C23.
+
+- New option ``-fprofile-continuous`` added to enable continuous profile syncing to file (#GH124353, `docs <https://clang.llvm.org/docs/UsersManual.html#cmdoption-fprofile-continuous>`_).
+ The feature has `existed <https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#running-the-instrumented-program>`_)
+ for a while and this is just a user facing option.
+
+- New option ``-ftime-report-json`` added which outputs the same timing data as ``-ftime-report`` but formatted as JSON.
+
+- New option ``-Wnrvo`` added and disabled by default to warn about missed NRVO opportunities.
+
+- New option ``-ignore-pch`` added to disable precompiled headers. It overrides ``-emit-pch`` and ``-include-pch``. (#GH142409, `PCHDocs <https://clang.llvm.org/docs/UsersManual.html#ignoring-a-pch-file>`_).
+
+- New options ``-g[no-]key-instructions`` added, disabled by default. Reduces jumpiness of debug stepping for optimized code in some debuggers (not LLDB at this time). Not recommended for use without optimizations. DWARF only. Note both the positive and negative flags imply ``-g``.
+
+- New option ``-foverflow-behavior-types`` added to enable parsing of the ``overflow_behavior`` type attribute.
+
Deprecated Compiler Flags
-------------------------
@@ -231,6 +247,10 @@ Removed Compiler Flags
Attribute Changes in Clang
--------------------------
+- Introduced a new type attribute ``__attribute__((overflow_behavior))`` which
+ currently accepts either ``wrap`` or ``no_wrap`` as an argument, enabling
+ type-level control over overflow behavior.
+
Improvements to Clang's diagnostics
-----------------------------------
- Added a separate diagnostic group ``-Wfunction-effect-redeclarations``, for the more pedantic
diff --git a/clang/docs/SanitizerSpecialCaseList.rst b/clang/docs/SanitizerSpecialCaseList.rst
index 307c001664fba..263b442ac8a41 100644
--- a/clang/docs/SanitizerSpecialCaseList.rst
+++ b/clang/docs/SanitizerSpecialCaseList.rst
@@ -134,6 +134,40 @@ precedence. Here are a few examples.
fun:*bar
fun:bad_bar=sanitize
+Interaction with Overflow Behavior Types
+----------------------------------------
+
+The ``overflow_behavior`` attribute provides a more granular, source-level
+control that takes precedence over the Sanitizer Special Case List. If a type
+is given an ``overflow_behavior`` attribute, it will override any matching
+``type:`` entry in a special case list.
+
+This allows developers to enforce a specific overflow behavior for a critical
+type, even if a broader rule in the special case list would otherwise disable
+instrumentation for it.
+
+.. code-block:: bash
+
+ $ cat ignorelist.txt
+ # Disable signed overflow checks for all types by default.
+ [signed-integer-overflow]
+ type:*
+
+ $ cat foo.c
+ // Force 'critical_type' to always have overflow checks,
+ // overriding the ignorelist.
+ typedef int __attribute__((overflow_behavior(no_wrap))) critical_type;
+
+ void foo(int x) {
+ critical_type a = x;
+ a++; // Overflow is checked here due to the 'no_wrap' attribute.
+
+ int b = x;
+ b++; // Overflow is NOT checked here due to the ignorelist.
+ }
+
+For more details on overflow behavior types, see :doc:`OverflowBehaviorTypes`.
+
Format
======
diff --git a/clang/docs/UndefinedBehaviorSanitizer.rst b/clang/docs/UndefinedBehaviorSanitizer.rst
index 0a2d833783e57..49dded2d5db88 100644
--- a/clang/docs/UndefinedBehaviorSanitizer.rst
+++ b/clang/docs/UndefinedBehaviorSanitizer.rst
@@ -380,6 +380,42 @@ This attribute may not be
supported by other compilers, so consider using it together with
``#if defined(__clang__)``.
+Disabling Overflow Instrumentation with ``__attribute__((overflow_behavior(wrap)))``
+------------------------------------------------------------------------------------
+
+For more fine-grained control over how integer overflow is handled, you can use
+the ``__attribute__((overflow_behavior(wrap)))`` attribute. This attribute can
+be applied to ``typedef`` declarations and integer types to specify that
+arithmetic operations on that type should wrap on overflow. This can be used to
+disable overflow sanitization for specific types, while leaving it enabled for
+all other types.
+
+The ``overflow_behavior`` attribute not only affects UBSan instrumentation
+but also changes the fundamental overflow behavior of arithmetic operations
+on the annotated type. Operations on types marked with ``wrap`` will have
+well-defined wrapping semantics, while operations on types marked with
+``no_wrap`` will be checked for overflow (regardless of global flags like
+``-fwrapv``).
+
+The attribute also affects implicit type promotion rules: when an overflow
+behavior type participates in arithmetic operations with standard integer
+types, the result maintains the overflow behavior type's characteristics,
+including its bit-width. This means annotated types can preserve narrower
+widths that would normally be promoted, allowing operations to stay within
+the constraints of the smallest annotated type in the expression.
+
+For more information, see :doc:`OverflowBehaviorTypes`.
+
+Enforcing Overflow Instrumentation with ``__attribute__((overflow_behavior(no_wrap)))``
+---------------------------------------------------------------------------------------
+
+Conversely, you can use ``__attribute__((overflow_behavior(no_wrap)))`` to
+enforce overflow checks for a specific type, even when ``-fwrapv`` is enabled
+globally. This is useful for ensuring that critical calculations are always
+checked for overflow, regardless of the global compiler settings.
+
+For more information, see :doc:`OverflowBehaviorTypes`.
+
Suppressing Errors in Recompiled Code (Ignorelist)
--------------------------------------------------
diff --git a/clang/docs/index.rst b/clang/docs/index.rst
index be654af57f890..d384f477b5e6d 100644
--- a/clang/docs/index.rst
+++ b/clang/docs/index.rst
@@ -40,6 +40,7 @@ Using Clang as a Compiler
SanitizerCoverage
SanitizerStats
SanitizerSpecialCaseList
+ OverflowBehaviorTypes
BoundsSafety
BoundsSafetyAdoptionGuide
BoundsSafetyImplPlans
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index 1c17333b722f8..2a36b704be23b 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -14,6 +14,7 @@
#ifndef LLVM_CLANG_AST_ASTCONTEXT_H
#define LLVM_CLANG_AST_ASTCONTEXT_H
+#include "Type.h"
#include "clang/AST/ASTFwd.h"
#include "clang/AST/CanonicalType.h"
#include "clang/AST/CommentCommandTraits.h"
@@ -262,6 +263,7 @@ class ASTContext : public RefCountedBase<ASTContext> {
mutable llvm::ContextualFoldingSet<DependentBitIntType, ASTContext &>
DependentBitIntTypes;
mutable llvm::FoldingSet<BTFTagAttributedType> BTFTagAttributedTypes;
+ mutable llvm::FoldingSet<OverflowBehaviorType> OverflowBehaviorTypes;
llvm::FoldingSet<HLSLAttributedResourceType> HLSLAttributedResourceTypes;
llvm::FoldingSet<HLSLInlineSpirvType> HLSLInlineSpirvTypes;
@@ -906,6 +908,8 @@ class ASTContext : public RefCountedBase<ASTContext> {
bool isTypeIgnoredBySanitizer(const SanitizerMask &Mask,
const QualType &Ty) const;
+ bool isUnaryOverflowPatternExcluded(const UnaryOperator *UO);
+
const XRayFunctionFilter &getXRayFilter() const {
return *XRayFilter;
}
@@ -1006,6 +1010,15 @@ class ASTContext : public RefCountedBase<ASTContext> {
comments::FullComment *getCommentForDecl(const Decl *D,
const Preprocessor *PP) const;
+ /// Attempts to merge two types that may be OverflowBehaviorTypes.
+ ///
+ /// \returns A QualType if the types were handled, std::nullopt otherwise.
+ /// A null QualType indicates an incompatible merge.
+ std::optional<QualType>
+ tryMergeOverflowBehaviorTypes(QualType LHS, QualType RHS, bool OfBlockPointer,
+ bool Unqualified, bool BlockReturnType,
+ bool IsConditionalOperator);
+
/// Return parsed documentation comment attached to a given declaration.
/// Returns nullptr if no comment is attached. Does not look at any
/// redeclarations of the declaration.
@@ -1881,6 +1894,13 @@ class ASTContext : public RefCountedBase<ASTContext> {
QualType getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
QualType Wrapped) const;
+ QualType getOverflowBehaviorType(const OverflowBehaviorAttr *Attr,
+ QualType Wrapped) const;
+
+ QualType
+ getOverflowBehaviorType(OverflowBehaviorType::OverflowBehaviorKind Kind,
+ QualType Wrapped) const;
+
QualType getHLSLAttributedResourceType(
QualType Wrapped, QualType Contained,
const HLSLAttributedResourceType::Attributes &Attrs);
diff --git a/clang/include/clang/AST/ASTNodeTraverser.h b/clang/include/clang/AST/ASTNodeTraverser.h
index fe08d637a1e1d..e0090da9a0d99 100644
--- a/clang/include/clang/AST/ASTNodeTraverser.h
+++ b/clang/include/clang/AST/ASTNodeTraverser.h
@@ -447,6 +447,9 @@ class ASTNodeTraverser
void VisitBTFTagAttributedType(const BTFTagAttributedType *T) {
Visit(T->getWrappedType());
}
+ void VisitOverflowBehaviorType(const OverflowBehaviorType *T) {
+ Visit(T->getUnderlyingType());
+ }
void VisitHLSLAttributedResourceType(const HLSLAttributedResourceType *T) {
QualType Contained = T->getContainedType();
if (!Contained.isNull())
diff --git a/clang/include/clang/AST/PropertiesBase.td b/clang/include/clang/AST/PropertiesBase.td
index 5b10127526e4e..4581e55c28027 100644
--- a/clang/include/clang/AST/PropertiesBase.td
+++ b/clang/include/clang/AST/PropertiesBase.td
@@ -81,6 +81,8 @@ def AutoTypeKeyword : EnumPropertyType;
def Bool : PropertyType<"bool">;
def BuiltinTypeKind : EnumPropertyType<"BuiltinType::Kind">;
def BTFTypeTagAttr : PropertyType<"const BTFTypeTagAttr *">;
+def OverflowBehaviorKind
+ : EnumPropertyType<"OverflowBehaviorType::OverflowBehaviorKind">;
def CallingConv : EnumPropertyType;
def DeclarationName : PropertyType;
def DeclarationNameKind : EnumPropertyType<"DeclarationName::NameKind">;
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index 02581c8e73299..c21c69f2d8bfd 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -1157,6 +1157,9 @@ DEF_TRAVERSE_TYPE(CountAttributedType, {
DEF_TRAVERSE_TYPE(BTFTagAttributedType,
{ TRY_TO(TraverseType(T->getWrappedType())); })
+DEF_TRAVERSE_TYPE(OverflowBehaviorType,
+ { TRY_TO(TraverseType(T->getUnderlyingType())); })
+
DEF_TRAVERSE_TYPE(HLSLAttributedResourceType,
{ TRY_TO(TraverseType(T->getWrappedType())); })
@@ -1519,6 +1522,9 @@ DEF_TRAVERSE_TYPELOC(CountAttributedType,
DEF_TRAVERSE_TYPELOC(BTFTagAttributedType,
{ TRY_TO(TraverseTypeLoc(TL.getWrappedLoc())); })
+DEF_TRAVERSE_TYPELOC(OverflowBehaviorType,
+ { TRY_TO(TraverseTypeLoc(TL.getWrappedLoc())); })
+
DEF_TRAVERSE_TYPELOC(HLSLAttributedResourceType,
{ TRY_TO(TraverseTypeLoc(TL.getWrappedLoc())); })
diff --git a/clang/include/clang/AST/TypeBase.h b/clang/include/clang/AST/TypeBase.h
index db2ab04e4471c..6e1c3e8ef6cb3 100644
--- a/clang/include/clang/AST/TypeBase.h
+++ b/clang/include/clang/AST/TypeBase.h
@@ -1149,6 +1149,12 @@ class QualType {
/// Returns true if it is a WebAssembly Funcref Type.
bool isWebAssemblyFuncrefType() const;
+ /// Returns true if it is a OverflowBehaviorType of Wrap kind.
+ bool isWrapType() const;
+
+ /// Returns true if it is a OverflowBehaviorType of NoWrap kind.
+ bool isNoWrapType() const;
+
// Don't promise in the API that anything besides 'const' can be
// easily added.
@@ -2661,6 +2667,7 @@ class alignas(TypeAlignment) Type : public ExtQualsTypeCommonBase {
bool isSubscriptableVectorType() const;
bool isMatrixType() const; // Matrix type.
bool isConstantMatrixType() const; // Constant matrix type.
+ bool isOverflowBehaviorType() const; // __attribute__((no_sanitize))
bool isDependentAddressSpaceType() const; // value-dependent address space qualifier
bool isObjCObjectPointerType() const; // pointer to ObjC object
bool isObjCRetainableType() const; // ObjC object or block pointer
@@ -6706,6 +6713,46 @@ class BTFTagAttributedType : public Type, public llvm::FoldingSetNode {
}
};
+class OverflowBehaviorType : public Type, public llvm::FoldingSetNode {
+public:
+ enum OverflowBehaviorKind { Wrap, NoWrap };
+
+private:
+ friend class ASTContext; // ASTContext creates these
+
+ QualType UnderlyingType;
+ OverflowBehaviorKind BehaviorKind;
+
+ OverflowBehaviorType(QualType Canon, QualType Underlying,
+ OverflowBehaviorKind Kind);
+
+public:
+ QualType getUnderlyingType() const { return UnderlyingType; }
+ OverflowBehaviorKind getBehaviorKind() const { return BehaviorKind; }
+
+ bool isWrapKind() const { return BehaviorKind == OverflowBehaviorKind::Wrap; }
+ bool isNoWrapKind() const {
+ return BehaviorKind == OverflowBehaviorKind::NoWrap;
+ }
+
+ bool isSugared() const { return false; }
+ QualType desugar() const { return getUnderlyingType(); }
+
+ void Profile(llvm::FoldingSetNodeID &ID) {
+ Profile(ID, UnderlyingType, BehaviorKind);
+ }
+
+ static void Profile(llvm::FoldingSetNodeID &ID, QualType Underlying,
+ OverflowBehaviorKind Kind) {
+ ID.AddPointer(Underlying.getAsOpaquePtr());
+ ID.AddInteger((int)Kind);
+ }
+
+ static bool classof(const Type *T) {
+ return T->getTypeClass() == OverflowBehavior;
+ }
+};
+
class HLSLAttributedResourceType : public Type, public llvm::FoldingSetNode {
public:
struct Attributes {
@@ -8742,6 +8789,10 @@ inline bool Type::isConstantMatrixType() const {
return isa<ConstantMatrixType>(CanonicalType);
}
+inline bool Type::isOverflowBehaviorType() const {
+ return isa<OverflowBehaviorType>(CanonicalType);
+}
+
inline bool Type::isDependentAddressSpaceType() const {
return isa<DependentAddressSpaceType>(CanonicalType);
}
@@ -8986,6 +9037,10 @@ inline bool Type::isIntegerType() const {
return IsEnumDeclComplete(ET->getOriginalDecl()) &&
!IsEnumDeclScoped(ET->getOriginalDecl());
}
+
+ if (const auto *OT = dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OT->getUnderlyingType()->isIntegerType();
+
return isBitIntType();
}
@@ -9048,7 +9103,7 @@ inline bool Type::isScalarType() const {
isa<MemberPointerType>(CanonicalType) ||
isa<ComplexType>(CanonicalType) ||
isa<ObjCObjectPointerType>(CanonicalType) ||
- isBitIntType();
+ isOverflowBehaviorType() || isBitIntType();
}
inline bool Type::isIntegralOrEnumerationType() const {
@@ -9060,6 +9115,10 @@ inline bool Type::isIntegralOrEnumerationType() const {
if (const auto *ET = dyn_cast<EnumType>(CanonicalType))
return IsEnumDeclComplete(ET->getOriginalDecl());
+ if (const OverflowBehaviorType *OBT =
+ dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isIntegralOrEnumerationType();
+
return isBitIntType();
}
diff --git a/clang/include/clang/AST/TypeLoc.h b/clang/include/clang/AST/TypeLoc.h
index d52e10419e97a..3193d89be5ba3 100644
--- a/clang/include/clang/AST/TypeLoc.h
+++ b/clang/include/clang/AST/TypeLoc.h
@@ -1082,6 +1082,34 @@ class BTFTagAttributedTypeLoc
QualType getInnerType() const { return getTypePtr()->getWrappedType(); }
};
+struct OverflowBehaviorLocInfo {
+ SourceLocation AttrLoc;
+};
+
+class OverflowBehaviorTypeLoc
+ : public ConcreteTypeLoc<UnqualTypeLoc, OverflowBehaviorTypeLoc,
+ OverflowBehaviorType, OverflowBehaviorLocInfo> {
+public:
+ TypeLoc getWrappedLoc() const { return getInnerTypeLoc(); }
+
+ /// The no_sanitize type attribute.
+ OverflowBehaviorType::OverflowBehaviorKind getBehaviorKind() const {
+ return getTypePtr()->getBehaviorKind();
+ }
+
+ SourceRange getLocalSourceRange() const;
+
+ void initializeLocal(ASTContext &Context, SourceLocation loc) {
+ setAttrLoc(loc);
+ }
+
+ SourceLocation getAttrLoc() const { return getLocalData()->AttrLoc; }
+
+ void setAttrLoc(SourceLocation loc) { getLocalData()->AttrLoc = loc; }
+
+ QualType getInnerType() const { return getTypePtr()->getUnderlyingType(); }
+};
+
struct HLSLAttributedResourceLocInfo {
SourceRange Range;
TypeSourceInfo *ContainedTyInfo;
diff --git a/clang/include/clang/AST/TypeProperties.td b/clang/include/clang/AST/TypeProperties.td
index 185a968217f97..03513c0ef237b 100644
--- a/clang/include/clang/AST/TypeProperties.td
+++ b/clang/include/clang/AST/TypeProperties.td
@@ -652,6 +652,19 @@ let Class = BTFTagAttributedType in {
}]>;
}
+let Class = OverflowBehaviorType in {
+ def : Property<"behaviorKind", OverflowBehaviorKind> {
+ let Read = [{ node->getBehaviorKind() }];
+ }
+ def : Property<"underlyingType", QualType> {
+ let Read = [{ node->getUnderlyingType() }];
+ }
+
+ def : Creator<[{
+ return ctx.getOverflowBehaviorType(behaviorKind, underlyingType);
+ }]>;
+}
+
let Class = HLSLAttributedResourceType in {
def : Property<"resClass", UInt32> {
let Read = [{ static_cast<uint32_t>(node->getAttrs().ResourceClass) }];
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index b85abfcbecfcf..f0b624104f493 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -5253,3 +5253,10 @@ def NonString : InheritableAttr {
let Subjects = SubjectList<[Var, Field]>;
let Documentation = [NonStringDocs];
}
+
+def OverflowBehavior : TypeAttr {
+ let Spellings = [Clang<"overflow_behavior">];
+ let Args = [IdentifierArgument<"BehaviorKind">];
+ let Subjects = SubjectList<[Var, TypedefName, Field]>;
+ let Documentation = [Undocumented];
+}
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 0c994e0b5ca4d..d4e0ab97b6adf 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -117,8 +117,9 @@ def ObjCSignedCharBoolImplicitIntConversion :
DiagGroup<"objc-signed-char-bool-implicit-int-conversion">;
def Shorten64To32 : DiagGroup<"shorten-64-to-32">;
def ImplicitIntConversionOnNegation : DiagGroup<"implicit-int-conversion-on-negation">;
-def ImplicitIntConversion : DiagGroup<"implicit-int-conversion",
- [Shorten64To32,
+def ImplicitIntConversion
+ : DiagGroup<
+ "implicit-int-conversion", [Shorten64To32,
ObjCSignedCharBoolImplicitIntConversion,
ImplicitIntConversionOnNegation]>;
def ImplicitConstIntFloatConversion : DiagGroup<"implicit-const-int-float-conversion">;
@@ -130,6 +131,17 @@ def ImplicitFloatConversion : DiagGroup<"implicit-float-conversion",
[ImplicitIntFloatConversion,
ObjCSignedCharBoolImplicitFloatConversion]>;
def ImplicitFixedPointConversion : DiagGroup<"implicit-fixed-point-conversion">;
+def ImplicitOverflowBehaviorConversionAssignment
+ : DiagGroup<"implicit-overflow-behavior-conversion-assignment">;
+def ImplicitOverflowBehaviorConversionPedantic
+ : DiagGroup<"implicit-overflow-behavior-conversion-pedantic">;
+def ImplicitOverflowBehaviorConversion
+ : DiagGroup<"implicit-overflow-behavior-conversion",
+ [ImplicitOverflowBehaviorConversionAssignment,
+ ImplicitOverflowBehaviorConversionPedantic]>;
+def OverflowBehaviorConversion
+ : DiagGroup<
+ "overflow-behavior-conversion", [ImplicitOverflowBehaviorConversion]>;
def FloatOverflowConversion : DiagGroup<"float-overflow-conversion">;
def FloatZeroConversion : DiagGroup<"float-zero-conversion">;
@@ -561,12 +573,15 @@ def IncompatibleMSStruct : DiagGroup<"incompatible-ms-struct">;
def IncompatibleMSPragmaSection : DiagGroup<"incompatible-ms-pragma-section">;
def IncompatiblePointerTypesDiscardsQualifiers
: DiagGroup<"incompatible-pointer-types-discards-qualifiers">;
+def IncompatiblePointerTypesDiscardsOverflowBehavior
+ : DiagGroup<"incompatible-pointer-types-discards-overflow-behavior">;
def IncompatibleFunctionPointerTypes
: DiagGroup<"incompatible-function-pointer-types">;
def IncompatiblePointerTypes
- : DiagGroup<"incompatible-pointer-types",
- [IncompatiblePointerTypesDiscardsQualifiers,
- IncompatibleFunctionPointerTypes]>;
+ : DiagGroup<"incompatible-pointer-types",
+ [IncompatiblePointerTypesDiscardsQualifiers,
+ IncompatiblePointerTypesDiscardsOverflowBehavior,
+ IncompatibleFunctionPointerTypes]>;
def IncompleteUmbrella : DiagGroup<"incomplete-umbrella">;
def IncompleteFrameworkModuleDeclaration
: DiagGroup<"incomplete-framework-module-declaration">;
@@ -1146,23 +1161,16 @@ def Parentheses : DiagGroup<"parentheses",
// - conversion warnings for literals are on by default
// - bool-to-pointer conversion warnings are on by default
// - __null-to-integer conversion warnings are on by default
-def Conversion : DiagGroup<"conversion",
- [BoolConversion,
- CharacterConversion,
- ConstantConversion,
- EnumConversion,
- BitFieldEnumConversion,
- FloatConversion,
- IntConversion,
- ImplicitIntConversion,
- ImplicitFloatConversion,
- LiteralConversion,
- NonLiteralNullConversion, // (1-1)->pointer (etc)
- NullConversion, // NULL->non-pointer
- ObjCLiteralConversion,
- SignConversion,
- StringConversion]>,
- DiagCategory<"Value Conversion Issue">;
+def Conversion
+ : DiagGroup<"conversion",
+ [BoolConversion, CharacterConversion, ConstantConversion,
+ EnumConversion, BitFieldEnumConversion, FloatConversion,
+ IntConversion, ImplicitIntConversion, ImplicitFloatConversion,
+ OverflowBehaviorConversion, LiteralConversion,
+ NonLiteralNullConversion, // (1-1)->pointer (etc)
+ NullConversion, // NULL->non-pointer
+ ObjCLiteralConversion, SignConversion, StringConversion]>,
+ DiagCategory<"Value Conversion Issue">;
def Unused : DiagGroup<"unused",
[UnusedArgument, UnusedFunction, UnusedLabel,
@@ -1666,6 +1674,9 @@ def CTADMaybeUnsupported : DiagGroup<"ctad-maybe-unsupported">;
def FortifySource : DiagGroup<"fortify-source", [FormatOverflow, FormatTruncation]>;
+def OverflowBehaviorAttributeIgnored
+ : DiagGroup<"overflow-behavior-attribute-ignored">;
+
def MaxTokens : DiagGroup<"max-tokens"> {
code Documentation = [{
The warning is issued if the number of pre-processor tokens exceeds
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index e69123bb3715d..b7db1ef8bec95 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4043,6 +4043,32 @@ def note_cannot_use_trivial_abi_reason : Note<
"it has a __weak field|it has a field of a non-trivial class type|"
"it has an address-discriminated '__ptrauth' field}1">;
+// OverflowBehavior attribute
+def err_overflow_behavior_unknown_ident
+ : Error<"'%0' is not a valid argument to attribute %1, only 'wrap' and "
+ "'no_wrap' "
+ "are supported">;
+def warn_overflow_behavior_non_integer_type
+ : Warning<"%0 attribute cannot be applied to non-integer type '%1'; "
+ "attribute ignored">,
+ InGroup<OverflowBehaviorAttributeIgnored>;
+def warn_overflow_behavior_attribute_disabled
+ : Warning<"%0 attribute is ignored because it is not enabled; pass "
+ "-foverflow-behavior-types">,
+ InGroup<OverflowBehaviorAttributeIgnored>;
+def warn_conflicting_overflow_behavior_attributes
+ : Warning<"conflicting 'overflow_behavior' attributes on the same type; "
+ "'no_wrap' takes precedence over 'wrap'">,
+ InGroup<OverflowBehaviorAttributeIgnored>;
+def warn_impcast_overflow_behavior_assignment
+ : Warning<"implicit conversion from %0 to %1 during assignment discards "
+ "overflow behavior">,
+ InGroup<ImplicitOverflowBehaviorConversionAssignment>,
+ DefaultIgnore;
+def warn_impcast_overflow_behavior_pedantic
+ : Warning<"implicit conversion from %0 to %1 discards overflow behavior">,
+ InGroup<ImplicitOverflowBehaviorConversionPedantic>,
+ DefaultIgnore;
// Availability attribute
def warn_availability_unknown_platform : Warning<
"unknown platform %0 in availability macro">, InGroup<Availability>;
@@ -4324,6 +4350,10 @@ def warn_impcast_vector_scalar : Warning<
def warn_impcast_complex_scalar : Warning<
"implicit conversion discards imaginary component: %0 to %1">,
InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_overflow_behavior
+ : Warning<"implicit conversion from %0 to %1 discards overflow behavior">,
+ InGroup<ImplicitOverflowBehaviorConversion>,
+ DefaultIgnore;
def err_impcast_complex_scalar : Error<
"implicit conversion from %0 to %1 is not permitted in C++">;
def warn_impcast_float_precision : Warning<
@@ -9103,6 +9133,21 @@ def ext_typecheck_convert_discards_qualifiers : ExtWarn<
"|%diff{casting $ to type $|casting between types}0,1}2"
" discards qualifiers">,
InGroup<IncompatiblePointerTypesDiscardsQualifiers>;
+def ext_typecheck_convert_discards_overflow_behavior
+ : ExtWarn<
+ "%select{%diff{assigning to $ from $|assigning to different types}0,1"
+ "|%diff{passing $ to parameter of type $|"
+ "passing to parameter of different type}0,1"
+ "|%diff{returning $ from a function with result type $|"
+ "returning from function with different return type}0,1"
+ "|%diff{converting $ to type $|converting between types}0,1"
+ "|%diff{initializing $ with an expression of type $|"
+ "initializing with expression of different type}0,1"
+ "|%diff{sending $ to parameter of type $|"
+ "sending to parameter of different type}0,1"
+ "|%diff{casting $ to type $|casting between types}0,1}2"
+ " discards overflow behavior">,
+ InGroup<IncompatiblePointerTypesDiscardsOverflowBehavior>;
def err_typecheck_convert_discards_qualifiers : Error<
"%select{%diff{assigning to $ from $|assigning to different types}0,1"
"|%diff{passing $ to parameter of type $|"
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 84f5ab3443a59..0ea6dd1f69728 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -426,6 +426,8 @@ LANGOPT(FixedPoint, 1, 0, NotCompatible, "fixed point types")
LANGOPT(PaddingOnUnsignedFixedPoint, 1, 0, NotCompatible,
"unsigned fixed point types having one extra padding bit")
+LANGOPT(OverflowBehaviorTypes, 1, 0, NotCompatible, "overflow behavior types")
+
ENUM_LANGOPT(RegisterStaticDestructors, RegisterStaticDestructorsKind, 2,
RegisterStaticDestructorsKind::All, NotCompatible,
"Register C++ static destructors")
diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h
index a8943df5b39aa..b36b4c030657a 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -112,6 +112,25 @@ class LangOptionsBase {
SOB_Trapping
};
+ // Used by __attribute__((overflow_behavior())) to describe overflow behavior
+ // on a per-type basis.
+ enum OverflowBehaviorKind {
+ // Default C standard behavior (type dependent).
+ OB_Unset,
+
+ // __attribute__((overflow_behavior("wrap")))
+ OB_Wrap,
+
+ // __attribute__((overflow_behavior("no_wrap")))
+ OB_NoWrap,
+
+ // Signed types defined as wrapping via -fwrapv can still be instrumented
+ // by sanitizers (PR82432). This field is needed to disambiguate canonical
+ // wrapping type behaviors from -fwrapv behaviors.
+ // -fwrapv
+ OB_FWrapv
+ };
+
// FIXME: Unify with TUKind.
enum CompilingModuleKind {
/// Not compiling a module interface at all.
diff --git a/clang/include/clang/Basic/TypeNodes.td b/clang/include/clang/Basic/TypeNodes.td
index fb6862b90987f..cae78ba81d371 100644
--- a/clang/include/clang/Basic/TypeNodes.td
+++ b/clang/include/clang/Basic/TypeNodes.td
@@ -110,3 +110,4 @@ def AtomicType : TypeNode<Type>;
def BitIntType : TypeNode<Type>;
def DependentBitIntType : TypeNode<Type>, AlwaysDependent;
def PredefinedSugarType : TypeNode<Type>, NeverCanonical;
+def OverflowBehaviorType : TypeNode<Type>;
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index cc68348d04413..62447a829e5e1 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2328,6 +2328,12 @@ defm fixed_point : BoolFOption<"fixed-point",
PosFlag<SetTrue, [], [ClangOption, CC1Option], "Enable">,
NegFlag<SetFalse, [], [ClangOption], "Disable">,
BothFlags<[], [ClangOption], " fixed point types">>;
+defm overflow_behavior_types
+ : BoolFOption<"overflow-behavior-types", LangOpts<"OverflowBehaviorTypes">,
+ DefaultFalse,
+ PosFlag<SetTrue, [], [ClangOption, CC1Option], "Enable">,
+ NegFlag<SetFalse, [], [ClangOption], "Disable">,
+ BothFlags<[], [ClangOption], " overflow behavior types">>;
def cxx_static_destructors_EQ : Joined<["-"], "fc++-static-destructors=">, Group<f_Group>,
HelpText<"Controls which variables C++ static destructors are registered for">,
Values<"all,thread-local,none">,
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 88b67eed5fd37..123a2d1f5a23a 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -735,6 +735,11 @@ enum class AssignConvertType {
/// like address spaces.
IncompatiblePointerDiscardsQualifiers,
+ /// IncompatiblePointerDiscardsOverflowBehavior - The assignment
+ /// discards overflow behavior annotations between otherwise compatible
+ /// pointer types.
+ IncompatiblePointerDiscardsOverflowBehavior,
+
/// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
/// changes address spaces in nested pointer types which is not allowed.
/// For instance, converting __private int ** to __generic int ** is
@@ -1338,6 +1343,10 @@ class Sema final : public SemaBase {
/// whether the next info diagnostic should be immediate.
bool IsLastErrorImmediate = true;
+ /// Track if we're currently analyzing overflow behavior types in assignment
+ /// context.
+ bool InOverflowBehaviorAssignmentContext = false;
+
class DelayedDiagnostics;
class DelayedDiagnosticsState {
@@ -2872,6 +2881,11 @@ class Sema final : public SemaBase {
bool *ICContext = nullptr,
bool IsListInit = false);
+ /// Check for overflow behavior type related implicit conversion diagnostics.
+ /// Returns true if OBT-related diagnostic was issued, false otherwise.
+ bool CheckOverflowBehaviorTypeConversion(Expr *E, QualType T,
+ SourceLocation CC);
+
bool
BuiltinElementwiseTernaryMath(CallExpr *TheCall,
EltwiseBuiltinArgTyRestriction ArgTyRestr =
@@ -10093,6 +10107,18 @@ class Sema final : public SemaBase {
/// floating-point or integral promotion.
bool IsComplexPromotion(QualType FromType, QualType ToType);
+ /// IsOverflowBehaviorTypePromotion - Determines whether the conversion from
+ /// FromType to ToType involves an OverflowBehaviorType FromType being
+ /// promoted to an OverflowBehaviorType ToType which has a larger bitwidth.
+ /// If so, returns true and sets FromType to ToType.
+ bool IsOverflowBehaviorTypePromotion(QualType FromType, QualType ToType);
+
+ /// IsOverflowBehaviorTypeConversion - Determines whether the conversion from
+ /// FromType to ToType necessarily involves both an OverflowBehaviorType and
+ /// a non-OverflowBehaviorType. If so, returns true and sets FromType to
+ /// ToType.
+ bool IsOverflowBehaviorTypeConversion(QualType FromType, QualType ToType);
+
/// IsPointerConversion - Determines whether the conversion of the
/// expression From, which has the (possibly adjusted) type FromType,
/// can be converted to the type ToType via a pointer conversion (C++
diff --git a/clang/include/clang/Serialization/TypeBitCodes.def b/clang/include/clang/Serialization/TypeBitCodes.def
index bea15254922c1..5afb5271a877b 100644
--- a/clang/include/clang/Serialization/TypeBitCodes.def
+++ b/clang/include/clang/Serialization/TypeBitCodes.def
@@ -70,5 +70,6 @@ TYPE_BIT_CODE(HLSLAttributedResource, HLSLRESOURCE_ATTRIBUTED, 59)
TYPE_BIT_CODE(HLSLInlineSpirv, HLSL_INLINE_SPIRV, 60)
TYPE_BIT_CODE(PredefinedSugar, PREDEFINED_SUGAR, 61)
TYPE_BIT_CODE(SubstBuiltinTemplatePack, SUBST_BUILTIN_TEMPLATE_PACK, 62)
+TYPE_BIT_CODE(OverflowBehavior, OVERFLOWBEHAVIOR, 63)
#undef TYPE_BIT_CODE
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index c04de4e132739..d0b72918a4d6f 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -873,6 +873,42 @@ ASTContext::insertCanonicalTemplateTemplateParmDeclInternal(
return CanonTTP;
}
+/// For the purposes of overflow pattern exclusion, does this match the
+/// while(i--) pattern?
+static bool matchesPostDecrInWhile(const UnaryOperator *UO, ASTContext &Ctx) {
+ if (UO->getOpcode() != UO_PostDec)
+ return false;
+
+ if (!UO->getType()->isUnsignedIntegerType())
+ return false;
+
+ // -fsanitize-undefined-ignore-overflow-pattern=unsigned-post-decr-while
+ if (!Ctx.getLangOpts().isOverflowPatternExcluded(
+ LangOptions::OverflowPatternExclusionKind::PostDecrInWhile))
+ return false;
+
+ // all Parents (usually just one) must be a WhileStmt
+ return llvm::all_of(
+ Ctx.getParentMapContext().getParents(*UO),
+ [](const DynTypedNode &P) { return P.get<WhileStmt>() != nullptr; });
+}
+
+bool ASTContext::isUnaryOverflowPatternExcluded(const UnaryOperator *UO) {
+ // -fsanitize-undefined-ignore-overflow-pattern=negated-unsigned-const
+ // ... like -1UL;
+ if (UO->getOpcode() == UO_Minus &&
+ getLangOpts().isOverflowPatternExcluded(
+ LangOptions::OverflowPatternExclusionKind::NegUnsignedConst) &&
+ UO->isIntegerConstantExpr(*this)) {
+ return true;
+ }
+
+ if (matchesPostDecrInWhile(UO, *this))
+ return true;
+
+ return false;
+}
+
/// Check if a type can have its sanitizer instrumentation elided based on its
/// presence within an ignorelist.
bool ASTContext::isTypeIgnoredBySanitizer(const SanitizerMask &Mask,
@@ -2554,6 +2590,10 @@ TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
return getTypeInfo(
cast<BTFTagAttributedType>(T)->getWrappedType().getTypePtr());
+ case Type::OverflowBehavior:
+ return getTypeInfo(
+ cast<OverflowBehaviorType>(T)->getUnderlyingType().getTypePtr());
+
case Type::HLSLAttributedResource:
return getTypeInfo(
cast<HLSLAttributedResourceType>(T)->getWrappedType().getTypePtr());
@@ -3586,6 +3626,9 @@ static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
case Type::HLSLInlineSpirv:
llvm_unreachable("should never get here");
break;
+ case Type::OverflowBehavior:
+ llvm_unreachable("should never get here");
+ break;
case Type::DeducedTemplateSpecialization:
case Type::Auto:
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
@@ -3731,6 +3774,12 @@ ASTContext::adjustType(QualType Orig,
adjustType(BTFT->getWrappedType(), Adjust));
}
+ case Type::OverflowBehavior: {
+ const auto *OB = dyn_cast<OverflowBehaviorType>(Orig);
+ return getOverflowBehaviorType(OB->getBehaviorKind(),
+ adjustType(OB->getUnderlyingType(), Adjust));
+ }
+
case Type::Paren:
return getParenType(
adjustType(cast<ParenType>(Orig)->getInnerType(), Adjust));
@@ -4299,6 +4348,7 @@ QualType ASTContext::getVariableArrayDecayedType(QualType type) const {
case Type::ArrayParameter:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
llvm_unreachable("type should never be variably-modified");
// These types can be variably-modified but should never need to
@@ -5760,6 +5810,52 @@ QualType ASTContext::getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
return QualType(Ty, 0);
}
+QualType ASTContext::getOverflowBehaviorType(const OverflowBehaviorAttr *Attr,
+ QualType Underlying) const {
+ IdentifierInfo *II = Attr->getBehaviorKind();
+ StringRef IdentName = II->getName();
+ OverflowBehaviorType::OverflowBehaviorKind Kind;
+ if (IdentName == "wrap") {
+ Kind = OverflowBehaviorType::OverflowBehaviorKind::Wrap;
+ } else if (IdentName == "no_wrap") {
+ Kind = OverflowBehaviorType::OverflowBehaviorKind::NoWrap;
+ } else {
+ return Underlying;
+ }
+
+ return getOverflowBehaviorType(Kind, Underlying);
+}
+
+QualType ASTContext::getOverflowBehaviorType(
+ OverflowBehaviorType::OverflowBehaviorKind Kind,
+ QualType Underlying) const {
+ llvm::FoldingSetNodeID ID;
+ OverflowBehaviorType::Profile(ID, Underlying, Kind);
+ void *InsertPos = nullptr;
+
+ if (OverflowBehaviorType *OBT =
+ OverflowBehaviorTypes.FindNodeOrInsertPos(ID, InsertPos)) {
+ return QualType(OBT, 0);
+ }
+
+ QualType Canonical;
+ if (!Underlying.isCanonical() || Underlying.hasLocalQualifiers()) {
+ SplitQualType canonSplit = getCanonicalType(Underlying).split();
+ Canonical = getOverflowBehaviorType(Kind, QualType(canonSplit.Ty, 0));
+ Canonical = getQualifiedType(Canonical, canonSplit.Quals);
+ [[maybe_unused]] OverflowBehaviorType *NewOBT =
+ OverflowBehaviorTypes.FindNodeOrInsertPos(ID, InsertPos);
+ assert(!NewOBT && "Shouldn't be in the map!");
+ }
+
+ OverflowBehaviorType *Ty = new (*this, alignof(OverflowBehaviorType))
+ OverflowBehaviorType(Canonical, Underlying, Kind);
+
+ Types.push_back(Ty);
+ OverflowBehaviorTypes.InsertNode(Ty, InsertPos);
+ return QualType(Ty, 0);
+}
+
QualType ASTContext::getHLSLAttributedResourceType(
QualType Wrapped, QualType Contained,
const HLSLAttributedResourceType::Attributes &Attrs) {
@@ -8232,6 +8328,9 @@ unsigned ASTContext::getIntegerRank(const Type *T) const {
if (const auto *EIT = dyn_cast<BitIntType>(T))
return 0 + (EIT->getNumBits() << 3);
+ if (const auto *OBT = dyn_cast<OverflowBehaviorType>(T))
+ return getIntegerRank(OBT->getUnderlyingType().getTypePtr());
+
switch (cast<BuiltinType>(T)->getKind()) {
default: llvm_unreachable("getIntegerRank(): not a built-in integer");
case BuiltinType::Bool:
@@ -9711,6 +9810,7 @@ void ASTContext::getObjCEncodingForTypeImpl(QualType T, std::string &S,
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
llvm_unreachable("unexpected type");
case Type::ArrayParameter:
@@ -11725,6 +11825,48 @@ QualType ASTContext::mergeTagDefinitions(QualType LHS, QualType RHS) {
return Ctx.IsEquivalent(LHS, RHS) ? LHS : QualType{};
}
+std::optional<QualType> ASTContext::tryMergeOverflowBehaviorTypes(
+ QualType LHS, QualType RHS, bool OfBlockPointer, bool Unqualified,
+ bool BlockReturnType, bool IsConditionalOperator) {
+ const auto *LHSOBT = LHS->getAs<OverflowBehaviorType>();
+ const auto *RHSOBT = RHS->getAs<OverflowBehaviorType>();
+
+ if (!LHSOBT && !RHSOBT)
+ return std::nullopt;
+
+ if (LHSOBT) {
+ if (RHSOBT) {
+ if (LHSOBT->getBehaviorKind() != RHSOBT->getBehaviorKind())
+ return QualType();
+
+ QualType MergedUnderlying = mergeTypes(
+ LHSOBT->getUnderlyingType(), RHSOBT->getUnderlyingType(),
+ OfBlockPointer, Unqualified, BlockReturnType, IsConditionalOperator);
+
+ if (MergedUnderlying.isNull())
+ return QualType();
+
+ if (getCanonicalType(LHSOBT) == getCanonicalType(RHSOBT)) {
+ if (LHSOBT->getUnderlyingType() == RHSOBT->getUnderlyingType())
+ return getCommonSugaredType(LHS, RHS);
+ return getOverflowBehaviorType(
+ LHSOBT->getBehaviorKind(),
+ getCanonicalType(LHSOBT->getUnderlyingType()));
+ }
+
+ // For different underlying types that successfully merge, wrap the
+ // merged underlying type with the common overflow behavior
+ return getOverflowBehaviorType(LHSOBT->getBehaviorKind(),
+ MergedUnderlying);
+ }
+ return mergeTypes(LHSOBT->getUnderlyingType(), RHS, OfBlockPointer,
+ Unqualified, BlockReturnType, IsConditionalOperator);
+ }
+
+ return mergeTypes(LHS, RHSOBT->getUnderlyingType(), OfBlockPointer,
+ Unqualified, BlockReturnType, IsConditionalOperator);
+}
+
QualType ASTContext::mergeTypes(QualType LHS, QualType RHS, bool OfBlockPointer,
bool Unqualified, bool BlockReturnType,
bool IsConditionalOperator) {
@@ -11745,6 +11887,11 @@ QualType ASTContext::mergeTypes(QualType LHS, QualType RHS, bool OfBlockPointer,
if (LHSRefTy || RHSRefTy)
return {};
+ if (std::optional<QualType> MergedOBT =
+ tryMergeOverflowBehaviorTypes(LHS, RHS, OfBlockPointer, Unqualified,
+ BlockReturnType, IsConditionalOperator))
+ return *MergedOBT;
+
if (Unqualified) {
LHS = LHS.getUnqualifiedType();
RHS = RHS.getUnqualifiedType();
@@ -11867,6 +12014,7 @@ QualType ASTContext::mergeTypes(QualType LHS, QualType RHS, bool OfBlockPointer,
case Type::VariableArray:
case Type::FunctionProto:
case Type::ExtVector:
+ case Type::OverflowBehavior:
llvm_unreachable("Types are eliminated above");
case Type::Pointer:
@@ -13909,23 +14057,30 @@ static QualType getCommonElementType(const ASTContext &Ctx, const T *X,
return Ctx.getCommonSugaredType(X->getElementType(), Y->getElementType());
}
-template <class T>
-static QualType getCommonArrayElementType(const ASTContext &Ctx, const T *X,
- Qualifiers &QX, const T *Y,
- Qualifiers &QY) {
- QualType EX = X->getElementType(), EY = Y->getElementType();
- QualType R = Ctx.getCommonSugaredType(EX, EY,
+static QualType getCommonTypeWithQualifierLifting(const ASTContext &Ctx,
+ QualType X, QualType Y,
+ Qualifiers &QX,
+ Qualifiers &QY) {
+ QualType R = Ctx.getCommonSugaredType(X, Y,
/*Unqualified=*/true);
// Qualifiers common to both element types.
Qualifiers RQ = R.getQualifiers();
// For each side, move to the top level any qualifiers which are not common to
// both element types. The caller must assume top level qualifiers might
// be different, even if they are the same type, and can be treated as sugar.
- QX += EX.getQualifiers() - RQ;
- QY += EY.getQualifiers() - RQ;
+ QX += X.getQualifiers() - RQ;
+ QY += Y.getQualifiers() - RQ;
return R;
}
+template <class T>
+static QualType getCommonArrayElementType(const ASTContext &Ctx, const T *X,
+ Qualifiers &QX, const T *Y,
+ Qualifiers &QY) {
+ return getCommonTypeWithQualifierLifting(Ctx, X->getElementType(),
+ Y->getElementType(), QX, QY);
+}
+
template <class T>
static QualType getCommonPointeeType(const ASTContext &Ctx, const T *X,
const T *Y) {
@@ -14323,6 +14478,15 @@ static QualType getCommonNonSugarTypeNode(const ASTContext &Ctx, const Type *X,
getCommonTypeKeyword(NX, NY, /*IsSame=*/true),
getCommonQualifier(Ctx, NX, NY, /*IsSame=*/true), NX->getIdentifier());
}
+ case Type::OverflowBehavior: {
+ const auto *NX = cast<OverflowBehaviorType>(X),
+ *NY = cast<OverflowBehaviorType>(Y);
+ assert(NX->getBehaviorKind() == NY->getBehaviorKind());
+ return Ctx.getOverflowBehaviorType(
+ NX->getBehaviorKind(),
+ getCommonTypeWithQualifierLifting(Ctx, NX->getUnderlyingType(),
+ NY->getUnderlyingType(), QX, QY));
+ }
case Type::DependentTemplateSpecialization: {
const auto *TX = cast<DependentTemplateSpecializationType>(X),
*TY = cast<DependentTemplateSpecializationType>(Y);
@@ -14411,6 +14575,7 @@ static QualType getCommonSugarTypeNode(const ASTContext &Ctx, const Type *X,
CANONICAL_TYPE(ObjCInterface)
CANONICAL_TYPE(ObjCObject)
CANONICAL_TYPE(ObjCObjectPointer)
+ CANONICAL_TYPE(OverflowBehavior)
CANONICAL_TYPE(Pipe)
CANONICAL_TYPE(Pointer)
CANONICAL_TYPE(Record)
@@ -14671,7 +14836,8 @@ QualType ASTContext::getCommonSugaredType(QualType X, QualType Y,
// The desired behaviour is the same as for the 'Unqualified' case here:
// treat the redundant qualifiers as sugar, remove the ones which are not
// common to both sides.
- bool KeepCommonQualifiers = Unqualified || isa<ArrayType>(SX.Ty);
+ bool KeepCommonQualifiers =
+ Unqualified || isa<ArrayType, OverflowBehaviorType>(SX.Ty);
if (SX.Ty != SY.Ty) {
// The canonical nodes differ. Build a common canonical node out of the two,
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index fe7f1e5eb0310..4bc3960f31871 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -2006,6 +2006,18 @@ ExpectedType clang::ASTNodeImporter::VisitBTFTagAttributedType(
ToWrappedType);
}
+ExpectedType clang::ASTNodeImporter::VisitOverflowBehaviorType(
+ const clang::OverflowBehaviorType *T) {
+ Error Err = Error::success();
+ OverflowBehaviorType::OverflowBehaviorKind ToKind = T->getBehaviorKind();
+ QualType ToUnderlyingType = importChecked(Err, T->getUnderlyingType());
+ if (Err)
+ return std::move(Err);
+
+ return Importer.getToContext().getOverflowBehaviorType(ToKind,
+ ToUnderlyingType);
+}
+
ExpectedType clang::ASTNodeImporter::VisitHLSLAttributedResourceType(
const clang::HLSLAttributedResourceType *T) {
Error Err = Error::success();
diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp
index 1292c30d47589..a143d615c918f 100644
--- a/clang/lib/AST/ASTStructuralEquivalence.cpp
+++ b/clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -1155,6 +1155,13 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
return false;
break;
+ case Type::OverflowBehavior:
+ if (!IsStructurallyEquivalent(
+ Context, cast<OverflowBehaviorType>(T1)->getUnderlyingType(),
+ cast<OverflowBehaviorType>(T2)->getUnderlyingType()))
+ return false;
+ break;
+
case Type::HLSLAttributedResource:
if (!IsStructurallyEquivalent(
Context, cast<HLSLAttributedResourceType>(T1)->getWrappedType(),
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 16f03c84384ae..d978f08387f46 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2904,7 +2904,7 @@ static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
Result = Value.trunc(LHS.getBitWidth());
- if (Result.extend(BitWidth) != Value) {
+ if (Result.extend(BitWidth) != Value && !E->getType().isWrapType()) {
if (Info.checkingForUndefinedBehavior())
Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
diag::warn_integer_constant_overflow)
@@ -12971,6 +12971,7 @@ GCCTypeClass EvaluateBuiltinClassifyType(QualType T,
case Type::Pipe:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
// Classify all other types that don't fit into the regular
// classification the same way.
return GCCTypeClass::None;
@@ -15676,7 +15677,8 @@ bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
return false;
if (!Result.isInt()) return Error(E);
const APSInt &Value = Result.getInt();
- if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow()) {
+ if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
+ !E->getType().isWrapType()) {
if (Info.checkingForUndefinedBehavior())
Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
diag::warn_integer_constant_overflow)
diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index d4cb89b43ae87..5f48e759b833b 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -405,6 +405,9 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
argTy = PT->getPointeeType();
}
+ if (const auto *OBT = argTy->getAs<OverflowBehaviorType>())
+ argTy = OBT->getUnderlyingType();
+
switch (K) {
case InvalidTy:
llvm_unreachable("ArgType must be valid");
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 163cd43abd45a..3b0e98c546bf9 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -2424,6 +2424,7 @@ bool CXXNameMangler::mangleUnresolvedTypeOrSimpleId(QualType Ty,
case Type::Paren:
case Type::Attributed:
case Type::BTFTagAttributed:
+ case Type::OverflowBehavior:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
case Type::Auto:
@@ -4619,6 +4620,17 @@ void CXXNameMangler::mangleType(const PipeType *T) {
Out << "8ocl_pipe";
}
+void CXXNameMangler::mangleType(const OverflowBehaviorType *T) {
+ // Vender-extended type mangling for OverflowBehaviorType
+ // <type> ::= U <behavior> <underlying_type>
+ if (T->isWrapKind()) {
+ Out << "U11ObtWrap_";
+ } else {
+ Out << "U13ObtNoWrap_";
+ }
+ mangleType(T->getUnderlyingType());
+}
+
void CXXNameMangler::mangleType(const BitIntType *T) {
// 5.1.5.2 Builtin types
// <type> ::= DB <number | instantiation-dependent expression> _
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index d96472e393f68..7fa9db7e95111 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -3791,6 +3791,24 @@ void MicrosoftCXXNameMangler::mangleType(const HLSLInlineSpirvType *T,
llvm_unreachable("HLSL uses Itanium name mangling");
}
+void MicrosoftCXXNameMangler::mangleType(const OverflowBehaviorType *T,
+ Qualifiers, SourceRange Range) {
+ QualType UnderlyingType = T->getUnderlyingType();
+
+ llvm::SmallString<64> TemplateMangling;
+ llvm::raw_svector_ostream Stream(TemplateMangling);
+ MicrosoftCXXNameMangler Extra(Context, Stream);
+ Stream << "?$";
+ if (T->isWrapKind()) {
+ Extra.mangleSourceName("ObtWrap_");
+ } else {
+ Extra.mangleSourceName("ObtNoWrap_");
+ }
+ Extra.mangleType(UnderlyingType, Range, QMM_Escape);
+
+ mangleArtificialTagType(TagTypeKind::Struct, TemplateMangling, {"__clang"});
+}
+
// <this-adjustment> ::= <no-adjustment> | <static-adjustment> |
// <virtual-adjustment>
// <no-adjustment> ::= A # private near
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 86621795d81e6..76898f88bd812 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -1153,6 +1153,18 @@ struct SimpleTransformVisitor : public TypeVisitor<Derived, QualType> {
T->getNumColumns());
}
+ QualType VisitOverflowBehaviorType(const OverflowBehaviorType *T) {
+ QualType UnderlyingType = recurse(T->getUnderlyingType());
+ if (UnderlyingType.isNull())
+ return {};
+
+ if (UnderlyingType.getAsOpaquePtr() ==
+ T->getUnderlyingType().getAsOpaquePtr())
+ return QualType(T, 0);
+
+ return Ctx.getOverflowBehaviorType(T->getBehaviorKind(), UnderlyingType);
+ }
+
QualType VisitFunctionNoProtoType(const FunctionNoProtoType *T) {
QualType returnType = recurse(T->getReturnType());
if (returnType.isNull())
@@ -2046,6 +2058,10 @@ class GetContainedDeducedTypeVisitor
return Visit(T->getUnderlyingType());
}
+ Type *VisitOverflowBehaviorType(const OverflowBehaviorType *T) {
+ return Visit(T->getUnderlyingType());
+ }
+
Type *VisitAdjustedType(const AdjustedType *T) {
return Visit(T->getOriginalType());
}
@@ -2109,10 +2125,15 @@ bool Type::isIntegralType(const ASTContext &Ctx) const {
return BT->isInteger();
// Complete enum types are integral in C.
- if (!Ctx.getLangOpts().CPlusPlus)
+ if (!Ctx.getLangOpts().CPlusPlus) {
if (const auto *ET = dyn_cast<EnumType>(CanonicalType))
return IsEnumDeclComplete(ET->getOriginalDecl());
+ if (const OverflowBehaviorType *OBT =
+ dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isIntegralOrEnumerationType();
+ }
+
return isBitIntType();
}
@@ -2120,6 +2141,10 @@ bool Type::isIntegralOrUnscopedEnumerationType() const {
if (const auto *BT = dyn_cast<BuiltinType>(CanonicalType))
return BT->isInteger();
+ if (const OverflowBehaviorType *OBT =
+ dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isIntegralOrUnscopedEnumerationType();
+
if (isBitIntType())
return true;
@@ -2223,6 +2248,9 @@ bool Type::isSignedIntegerType() const {
if (const auto *IT = dyn_cast<DependentBitIntType>(CanonicalType))
return IT->isSigned();
+ if (const auto *OBT = dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isSignedIntegerType();
+
return false;
}
@@ -2241,6 +2269,9 @@ bool Type::isSignedIntegerOrEnumerationType() const {
if (const auto *IT = dyn_cast<DependentBitIntType>(CanonicalType))
return IT->isSigned();
+ if (const auto *OBT = dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isSignedIntegerOrEnumerationType();
+
return false;
}
@@ -2271,6 +2302,9 @@ bool Type::isUnsignedIntegerType() const {
if (const auto *IT = dyn_cast<DependentBitIntType>(CanonicalType))
return IT->isUnsigned();
+ if (const auto *OBT = dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isUnsignedIntegerType();
+
return false;
}
@@ -2289,6 +2323,9 @@ bool Type::isUnsignedIntegerOrEnumerationType() const {
if (const auto *IT = dyn_cast<DependentBitIntType>(CanonicalType))
return IT->isUnsigned();
+ if (const auto *OBT = dyn_cast<OverflowBehaviorType>(CanonicalType))
+ return OBT->getUnderlyingType()->isUnsignedIntegerOrEnumerationType();
+
return false;
}
@@ -2352,6 +2389,11 @@ bool Type::isArithmeticType() const {
const auto *ED = ET->getOriginalDecl();
return !ED->isScoped() && ED->getDefinitionOrSelf()->isComplete();
}
+
+ if (isOverflowBehaviorType() &&
+ getAs<OverflowBehaviorType>()->getUnderlyingType()->isArithmeticType())
+ return true;
+
return isa<ComplexType>(CanonicalType) || isBitIntType();
}
@@ -2398,6 +2440,8 @@ Type::ScalarTypeKind Type::getScalarTypeKind() const {
return STK_IntegralComplex;
} else if (isBitIntType()) {
return STK_Integral;
+ } else if (isa<OverflowBehaviorType>(T)) {
+ return STK_Integral;
}
llvm_unreachable("unknown scalar type");
@@ -2744,6 +2788,7 @@ bool QualType::isCXX98PODType(const ASTContext &Context) const {
case Type::Vector:
case Type::ExtVector:
case Type::BitInt:
+ case Type::OverflowBehavior:
return true;
case Type::Enum:
@@ -2954,6 +2999,22 @@ bool QualType::isWebAssemblyFuncrefType() const {
getAddressSpace() == LangAS::wasm_funcref;
}
+bool QualType::isWrapType() const {
+ if (const auto *OBT = getCanonicalType()->getAs<OverflowBehaviorType>())
+ return OBT->getBehaviorKind() ==
+ OverflowBehaviorType::OverflowBehaviorKind::Wrap;
+
+ return false;
+}
+
+bool QualType::isNoWrapType() const {
+ if (const auto *OBT = getCanonicalType()->getAs<OverflowBehaviorType>())
+ return OBT->getBehaviorKind() ==
+ OverflowBehaviorType::OverflowBehaviorKind::NoWrap;
+
+ return false;
+}
+
QualType::PrimitiveDefaultInitializeKind
QualType::isNonTrivialToPrimitiveDefaultInitialize() const {
if (const auto *RD =
@@ -3052,6 +3113,9 @@ bool Type::isLiteralType(const ASTContext &Ctx) const {
if (const auto *AT = BaseTy->getAs<AtomicType>())
return AT->getValueType()->isLiteralType(Ctx);
+ if (const auto *OBT = BaseTy->getAs<OverflowBehaviorType>())
+ return OBT->getUnderlyingType()->isLiteralType(Ctx);
+
// If this type hasn't been deduced yet, then conservatively assume that
// it'll work out to be a literal type.
if (isa<AutoType>(BaseTy->getCanonicalTypeInternal()))
@@ -4013,6 +4077,12 @@ void TypeCoupledDeclRefInfo::setFromOpaqueValue(void *V) {
Data.setFromOpaqueValue(V);
}
+OverflowBehaviorType::OverflowBehaviorType(
+ QualType Canon, QualType Underlying,
+ OverflowBehaviorType::OverflowBehaviorKind Kind)
+ : Type(OverflowBehavior, Canon, Underlying->getDependence()),
+ UnderlyingType(Underlying), BehaviorKind(Kind) {}
+
BoundsAttributedType::BoundsAttributedType(TypeClass TC, QualType Wrapped,
QualType Canon)
: Type(TC, Canon, Wrapped->getDependence()), WrappedTy(Wrapped) {}
@@ -4934,6 +5004,8 @@ static CachedProperties computeCachedProperties(const Type *T) {
return Cache::get(cast<HLSLAttributedResourceType>(T)->getWrappedType());
case Type::HLSLInlineSpirv:
return CachedProperties(Linkage::External, false);
+ case Type::OverflowBehavior:
+ return Cache::get(cast<OverflowBehaviorType>(T)->getUnderlyingType());
}
llvm_unreachable("unhandled type class");
@@ -5029,6 +5101,9 @@ LinkageInfo LinkageComputer::computeTypeLinkageInfo(const Type *T) {
return computeTypeLinkageInfo(cast<AtomicType>(T)->getValueType());
case Type::Pipe:
return computeTypeLinkageInfo(cast<PipeType>(T)->getElementType());
+ case Type::OverflowBehavior:
+ return computeTypeLinkageInfo(
+ cast<OverflowBehaviorType>(T)->getUnderlyingType());
case Type::HLSLAttributedResource:
return computeTypeLinkageInfo(cast<HLSLAttributedResourceType>(T)
->getContainedType()
@@ -5224,6 +5299,7 @@ bool Type::canHaveNullability(bool ResultIfUnknown) const {
case Type::ArrayParameter:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
return false;
}
llvm_unreachable("bad type kind!");
diff --git a/clang/lib/AST/TypeLoc.cpp b/clang/lib/AST/TypeLoc.cpp
index 3e9597fc4d471..2601afb1f01dc 100644
--- a/clang/lib/AST/TypeLoc.cpp
+++ b/clang/lib/AST/TypeLoc.cpp
@@ -647,6 +647,10 @@ SourceRange BTFTagAttributedTypeLoc::getLocalSourceRange() const {
return getAttr() ? getAttr()->getRange() : SourceRange();
}
+SourceRange OverflowBehaviorTypeLoc::getLocalSourceRange() const {
+ return SourceRange();
+}
+
void TypeOfTypeLoc::initializeLocal(ASTContext &Context,
SourceLocation Loc) {
TypeofLikeTypeLoc<TypeOfTypeLoc, TypeOfType, TypeOfTypeLocInfo>
@@ -919,6 +923,10 @@ namespace {
return Visit(T.getWrappedLoc());
}
+ TypeLoc VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc T) {
+ return Visit(T.getWrappedLoc());
+ }
+
TypeLoc
VisitHLSLAttributedResourceTypeLoc(HLSLAttributedResourceTypeLoc T) {
return Visit(T.getWrappedLoc());
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index 54ca42d2035ad..e40f37d501f5c 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -289,6 +289,7 @@ bool TypePrinter::canPrefixQualifiers(const Type *T,
case Type::PackExpansion:
case Type::SubstTemplateTypeParm:
case Type::MacroQualified:
+ case Type::OverflowBehavior:
case Type::CountAttributed:
CanPrefixQualifiers = false;
break;
@@ -2102,6 +2103,7 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
case attr::PreserveAll:
case attr::PreserveMost:
case attr::PreserveNone:
+ case attr::OverflowBehavior:
llvm_unreachable("This attribute should have been handled already");
case attr::NSReturnsRetained:
@@ -2182,6 +2184,26 @@ void TypePrinter::printBTFTagAttributedAfter(const BTFTagAttributedType *T,
printAfter(T->getWrappedType(), OS);
}
+void TypePrinter::printOverflowBehaviorBefore(const OverflowBehaviorType *T,
+ raw_ostream &OS) {
+ StringRef KindName;
+ switch (T->getBehaviorKind()) {
+ case clang::OverflowBehaviorType::OverflowBehaviorKind::Wrap:
+ KindName = "__wrap";
+ break;
+ case clang::OverflowBehaviorType::OverflowBehaviorKind::NoWrap:
+ KindName = "__no_wrap";
+ break;
+ }
+ OS << KindName << " ";
+ printBefore(T->getUnderlyingType(), OS);
+}
+
+void TypePrinter::printOverflowBehaviorAfter(const OverflowBehaviorType *T,
+ raw_ostream &OS) {
+ printAfter(T->getUnderlyingType(), OS);
+}
+
void TypePrinter::printHLSLAttributedResourceBefore(
const HLSLAttributedResourceType *T, raw_ostream &OS) {
printBefore(T->getWrappedType(), OS);
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 578d09f7971d6..649c3e19047d9 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1115,6 +1115,11 @@ llvm::DIType *CGDebugInfo::CreateType(const BitIntType *Ty) {
Encoding);
}
+llvm::DIType *CGDebugInfo::CreateType(const OverflowBehaviorType *Ty,
+ llvm::DIFile *U) {
+ return getOrCreateType(Ty->getUnderlyingType(), U);
+}
+
llvm::DIType *CGDebugInfo::CreateType(const ComplexType *Ty) {
// Bit size and offset of the type.
llvm::dwarf::TypeKind Encoding = llvm::dwarf::DW_ATE_complex_float;
@@ -4060,6 +4065,8 @@ llvm::DIType *CGDebugInfo::CreateTypeNode(QualType Ty, llvm::DIFile *Unit) {
case Type::BitInt:
return CreateType(cast<BitIntType>(Ty));
+ case Type::OverflowBehavior:
+ return CreateType(cast<OverflowBehaviorType>(Ty), Unit);
case Type::Pipe:
return CreateType(cast<PipeType>(Ty), Unit);
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index f86077369a42a..8b26ef15df260 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -198,6 +198,7 @@ class CGDebugInfo {
llvm::DIType *CreateType(const BuiltinType *Ty);
llvm::DIType *CreateType(const ComplexType *Ty);
llvm::DIType *CreateType(const BitIntType *Ty);
+ llvm::DIType *CreateType(const OverflowBehaviorType *Ty, llvm::DIFile *U);
llvm::DIType *CreateQualifiedType(QualType Ty, llvm::DIFile *Fg);
llvm::DIType *CreateQualifiedType(const FunctionProtoType *Ty,
llvm::DIFile *Fg);
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 2eff3a387593c..9f25432a74c79 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -191,8 +191,42 @@ static bool IsWidenedIntegerOp(const ASTContext &Ctx, const Expr *E) {
return getUnwidenedIntegerType(Ctx, E).has_value();
}
+/// Consider OverflowBehaviorType and language options to calculate the final
+/// overflow behavior for an expression. There are no language options for
+/// unsigned overflow semantics so there is nothing to consider there.
+static LangOptions::OverflowBehaviorKind
+getOverflowBehaviorConsideringType(const CodeGenFunction &CGF,
+ const QualType Ty) {
+ const OverflowBehaviorType *OBT = Ty->getAs<OverflowBehaviorType>();
+ /// FIXME: Having two enums named `OverflowBehaviorKind` is not ideal, these
+ /// should be unified into one coherent enum that supports both unsigned and
+ /// signed overflow behavior semantics.
+ if (OBT) {
+ switch (OBT->getBehaviorKind()) {
+ case OverflowBehaviorType::OverflowBehaviorKind::Wrap:
+ return LangOptions::OverflowBehaviorKind::OB_Wrap;
+ case OverflowBehaviorType::OverflowBehaviorKind::NoWrap:
+ return LangOptions::OverflowBehaviorKind::OB_NoWrap;
+ }
+ llvm_unreachable("Unknown OverflowBehaviorKind");
+ }
+
+ if (Ty->isUnsignedIntegerType()) {
+ return LangOptions::OverflowBehaviorKind::OB_Unset;
+ }
+
+ switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
+ case LangOptions::SignedOverflowBehaviorTy::SOB_Defined:
+ return LangOptions::OverflowBehaviorKind::OB_FWrapv;
+ case LangOptions::SignedOverflowBehaviorTy::SOB_Undefined:
+ return LangOptions::OverflowBehaviorKind::OB_Unset;
+ case LangOptions::SignedOverflowBehaviorTy::SOB_Trapping:
+ return LangOptions::OverflowBehaviorKind::OB_NoWrap;
+ }
+}
+
/// Check if we can skip the overflow check for \p Op.
-static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) {
+static bool CanElideOverflowCheck(ASTContext &Ctx, const BinOpInfo &Op) {
assert((isa<UnaryOperator>(Op.E) || isa<BinaryOperator>(Op.E)) &&
"Expected a unary or binary operator");
@@ -201,6 +235,19 @@ static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) {
if (!Op.mayHaveIntegerOverflow())
return true;
+ const UnaryOperator *UO = dyn_cast<UnaryOperator>(Op.E);
+ if (UO && Ctx.isUnaryOverflowPatternExcluded(UO))
+ return true;
+
+ const auto *BO = dyn_cast<BinaryOperator>(Op.E);
+ if (BO && BO->hasExcludedOverflowPattern())
+ return true;
+
+ if (Op.Ty.isWrapType())
+ return true;
+ if (Op.Ty.isNoWrapType())
+ return false;
+
if (Op.Ty->isSignedIntegerType() &&
Ctx.isTypeIgnoredBySanitizer(SanitizerKind::SignedIntegerOverflow,
Op.Ty)) {
@@ -213,24 +260,12 @@ static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) {
return true;
}
- const UnaryOperator *UO = dyn_cast<UnaryOperator>(Op.E);
-
- if (UO && UO->getOpcode() == UO_Minus &&
- Ctx.getLangOpts().isOverflowPatternExcluded(
- LangOptions::OverflowPatternExclusionKind::NegUnsignedConst) &&
- UO->isIntegerConstantExpr(Ctx))
- return true;
-
// If a unary op has a widened operand, the op cannot overflow.
if (UO)
return !UO->canOverflow();
// We usually don't need overflow checks for binops with widened operands.
// Multiplication with promoted unsigned operands is a special case.
- const auto *BO = cast<BinaryOperator>(Op.E);
- if (BO->hasExcludedOverflowPattern())
- return true;
-
auto OptionalLHSTy = getUnwidenedIntegerType(Ctx, BO->getLHS());
if (!OptionalLHSTy)
return false;
@@ -776,19 +811,28 @@ class ScalarExprEmitter
// Binary Operators.
Value *EmitMul(const BinOpInfo &Ops) {
- if (Ops.Ty->isSignedIntegerOrEnumerationType()) {
- switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
- case LangOptions::SOB_Defined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
+ if (Ops.Ty->isSignedIntegerOrEnumerationType() ||
+ Ops.Ty->isUnsignedIntegerType()) {
+ const bool isSigned = Ops.Ty->isSignedIntegerOrEnumerationType();
+ const bool hasSan =
+ isSigned ? CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)
+ : CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow);
+ switch (getOverflowBehaviorConsideringType(CGF, Ops.Ty)) {
+ case LangOptions::OB_Wrap:
+ return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
+ case LangOptions::OB_FWrapv:
+ if (!hasSan)
return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
[[fallthrough]];
- case LangOptions::SOB_Undefined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
- return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
+ case LangOptions::OB_Unset:
+ if (!hasSan)
+ return isSigned ? Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul")
+ : Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
[[fallthrough]];
- case LangOptions::SOB_Trapping:
+ case LangOptions::OB_NoWrap:
if (CanElideOverflowCheck(CGF.getContext(), Ops))
- return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
+ return isSigned ? Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul")
+ : Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
return EmitOverflowCheckedBinOp(Ops);
}
}
@@ -810,11 +854,6 @@ class ScalarExprEmitter
return MB.CreateScalarMultiply(Ops.LHS, Ops.RHS);
}
- if (Ops.Ty->isUnsignedIntegerType() &&
- CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
- !CanElideOverflowCheck(CGF.getContext(), Ops))
- return EmitOverflowCheckedBinOp(Ops);
-
if (Ops.LHS->getType()->isFPOrFPVectorTy()) {
// Preserve the old values
CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures);
@@ -1164,8 +1203,16 @@ void ScalarExprEmitter::EmitIntegerTruncationCheck(Value *Src, QualType SrcType,
SanitizerDebugLocation SanScope(&CGF, {Check.second.second}, CheckHandler);
// Does some SSCL ignore this type?
- if (CGF.getContext().isTypeIgnoredBySanitizer(
- SanitizerMask::bitPosToMask(Check.second.second), DstType))
+ const bool ignoredBySanitizer = CGF.getContext().isTypeIgnoredBySanitizer(
+ SanitizerMask::bitPosToMask(Check.second.second), DstType);
+
+ // Consider OverflowBehaviorTypes which override SSCL type entries for
+ // truncation sanitizers.
+ if (const auto *OBT = DstType->getAs<OverflowBehaviorType>()) {
+ if (OBT->getBehaviorKind() !=
+ OverflowBehaviorType::OverflowBehaviorKind::NoWrap)
+ return;
+ } else if (ignoredBySanitizer)
return;
llvm::Constant *StaticArgs[] = {
@@ -3002,43 +3049,37 @@ llvm::Value *ScalarExprEmitter::EmitIncDecConsiderOverflowBehavior(
llvm::Value *Amount =
llvm::ConstantInt::get(InVal->getType(), IsInc ? 1 : -1, true);
StringRef Name = IsInc ? "inc" : "dec";
- switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
- case LangOptions::SOB_Defined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
+ QualType Ty = E->getType();
+ const bool isSigned = Ty->isSignedIntegerOrEnumerationType();
+ const bool hasSan =
+ isSigned ? CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)
+ : CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow);
+
+ switch (getOverflowBehaviorConsideringType(CGF, Ty)) {
+ case LangOptions::OB_Wrap:
+ return Builder.CreateAdd(InVal, Amount, Name);
+ case LangOptions::OB_FWrapv:
+ if (!hasSan)
return Builder.CreateAdd(InVal, Amount, Name);
[[fallthrough]];
- case LangOptions::SOB_Undefined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
- return Builder.CreateNSWAdd(InVal, Amount, Name);
+ case LangOptions::OB_Unset:
+ if (!E->canOverflow())
+ return Builder.CreateAdd(InVal, Amount, Name);
+ if (!hasSan)
+ return isSigned ? Builder.CreateNSWAdd(InVal, Amount, Name)
+ : Builder.CreateAdd(InVal, Amount, Name);
[[fallthrough]];
- case LangOptions::SOB_Trapping:
+ case LangOptions::OB_NoWrap:
+ if (!Ty->getAs<OverflowBehaviorType>() && !E->canOverflow())
+ return Builder.CreateAdd(InVal, Amount, Name);
BinOpInfo Info = createBinOpInfoFromIncDec(
E, InVal, IsInc, E->getFPFeaturesInEffect(CGF.getLangOpts()));
- if (!E->canOverflow() || CanElideOverflowCheck(CGF.getContext(), Info))
- return Builder.CreateNSWAdd(InVal, Amount, Name);
+ if (CanElideOverflowCheck(CGF.getContext(), Info))
+ return isSigned ? Builder.CreateNSWAdd(InVal, Amount, Name)
+ : Builder.CreateAdd(InVal, Amount, Name);
return EmitOverflowCheckedBinOp(Info);
}
- llvm_unreachable("Unknown SignedOverflowBehaviorTy");
-}
-
-/// For the purposes of overflow pattern exclusion, does this match the
-/// "while(i--)" pattern?
-static bool matchesPostDecrInWhile(const UnaryOperator *UO, bool isInc,
- bool isPre, ASTContext &Ctx) {
- if (isInc || isPre)
- return false;
-
- // -fsanitize-undefined-ignore-overflow-pattern=unsigned-post-decr-while
- if (!Ctx.getLangOpts().isOverflowPatternExcluded(
- LangOptions::OverflowPatternExclusionKind::PostDecrInWhile))
- return false;
-
- // all Parents (usually just one) must be a WhileStmt
- for (const auto &Parent : Ctx.getParentMapContext().getParents(*UO))
- if (!Parent.get<WhileStmt>())
- return false;
-
- return true;
+ llvm_unreachable("Unknown OverflowBehaviorKind");
}
namespace {
@@ -3157,9 +3198,6 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
QualType promotedType;
bool canPerformLossyDemotionCheck = false;
- bool excludeOverflowPattern =
- matchesPostDecrInWhile(E, isInc, isPre, CGF.getContext());
-
if (CGF.getContext().isPromotableIntegerType(type)) {
promotedType = CGF.getContext().getPromotedIntegerType(type);
assert(promotedType != type && "Shouldn't promote to the same type.");
@@ -3216,15 +3254,9 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
// Note that signed integer inc/dec with width less than int can't
// overflow because of promotion rules; we're just eliding a few steps
// here.
- } else if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
+ } else if (type->isSignedIntegerOrEnumerationType() ||
+ type->isUnsignedIntegerType()) {
value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
- } else if (E->canOverflow() && type->isUnsignedIntegerType() &&
- CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
- !excludeOverflowPattern &&
- !CGF.getContext().isTypeIgnoredBySanitizer(
- SanitizerKind::UnsignedIntegerOverflow, E->getType())) {
- value = EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(
- E, value, isInc, E->getFPFeaturesInEffect(CGF.getLangOpts())));
} else {
llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
@@ -4002,7 +4034,7 @@ void ScalarExprEmitter::EmitUndefinedBehaviorIntegerDivAndRemCheck(
if (CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow) &&
Ops.Ty->hasSignedIntegerRepresentation() &&
!IsWidenedIntegerOp(CGF.getContext(), BO->getLHS()) &&
- Ops.mayHaveIntegerOverflow()) {
+ Ops.mayHaveIntegerOverflow() && !Ops.Ty.isWrapType()) {
llvm::IntegerType *Ty = cast<llvm::IntegerType>(Zero->getType());
llvm::Value *IntMin =
@@ -4148,14 +4180,25 @@ Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
const std::string *handlerName =
&CGF.getLangOpts().OverflowHandler;
if (handlerName->empty()) {
- // If the signed-integer-overflow sanitizer is enabled, emit a call to its
- // runtime. Otherwise, this is a -ftrapv check, so just emit a trap.
- if (!isSigned || CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) {
- llvm::Value *NotOverflow = Builder.CreateNot(overflow);
- SanitizerKind::SanitizerOrdinal Ordinal =
- isSigned ? SanitizerKind::SO_SignedIntegerOverflow
- : SanitizerKind::SO_UnsignedIntegerOverflow;
- EmitBinOpCheck(std::make_pair(NotOverflow, Ordinal), Ops);
+ // If no -ftrapv handler has been specified, try to use sanitizer runtimes
+ // if available otherwise just emit a trap. It is possible for unsigned
+ // arithmetic to result in a trap due to the OverflowBehaviorType attribute
+ // which describes overflow behavior on a per-type basis.
+ if (isSigned) {
+ if (CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) {
+ llvm::Value *NotOf = Builder.CreateNot(overflow);
+ EmitBinOpCheck(
+ std::make_pair(NotOf, SanitizerKind::SO_SignedIntegerOverflow),
+ Ops);
+ } else
+ CGF.EmitTrapCheck(Builder.CreateNot(overflow), OverflowKind);
+ return result;
+ }
+ if (CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {
+ llvm::Value *NotOf = Builder.CreateNot(overflow);
+ EmitBinOpCheck(
+ std::make_pair(NotOf, SanitizerKind::SO_UnsignedIntegerOverflow),
+ Ops);
} else
CGF.EmitTrapCheck(Builder.CreateNot(overflow), OverflowKind);
return result;
@@ -4479,19 +4522,30 @@ Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
op.RHS->getType()->isPointerTy())
return emitPointerArithmetic(CGF, op, CodeGenFunction::NotSubtraction);
- if (op.Ty->isSignedIntegerOrEnumerationType()) {
- switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
- case LangOptions::SOB_Defined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
+ // FIXME: maybe we want to emit NUWAdd for unsigned non-wrapping types which
+ // should depend on -fwrapv (-fno-strict-overflow)
+ if (op.Ty->isSignedIntegerOrEnumerationType() ||
+ op.Ty->isUnsignedIntegerType()) {
+ const bool isSigned = op.Ty->isSignedIntegerOrEnumerationType();
+ const bool hasSan =
+ isSigned ? CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)
+ : CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow);
+ switch (getOverflowBehaviorConsideringType(CGF, op.Ty)) {
+ case LangOptions::OB_Wrap:
+ return Builder.CreateAdd(op.LHS, op.RHS, "add");
+ case LangOptions::OB_FWrapv:
+ if (!hasSan)
return Builder.CreateAdd(op.LHS, op.RHS, "add");
[[fallthrough]];
- case LangOptions::SOB_Undefined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
- return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
+ case LangOptions::OB_Unset:
+ if (!hasSan)
+ return isSigned ? Builder.CreateNSWAdd(op.LHS, op.RHS, "add")
+ : Builder.CreateAdd(op.LHS, op.RHS, "add");
[[fallthrough]];
- case LangOptions::SOB_Trapping:
+ case LangOptions::OB_NoWrap:
if (CanElideOverflowCheck(CGF.getContext(), op))
- return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
+ return isSigned ? Builder.CreateNSWAdd(op.LHS, op.RHS, "add")
+ : Builder.CreateAdd(op.LHS, op.RHS, "add");
return EmitOverflowCheckedBinOp(op);
}
}
@@ -4510,11 +4564,6 @@ Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
return MB.CreateAdd(op.LHS, op.RHS);
}
- if (op.Ty->isUnsignedIntegerType() &&
- CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
- !CanElideOverflowCheck(CGF.getContext(), op))
- return EmitOverflowCheckedBinOp(op);
-
if (op.LHS->getType()->isFPOrFPVectorTy()) {
CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
return Builder.CreateFAdd(op.LHS, op.RHS, "add");
@@ -4635,19 +4684,28 @@ Value *ScalarExprEmitter::EmitFixedPointBinOp(const BinOpInfo &op) {
Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
// The LHS is always a pointer if either side is.
if (!op.LHS->getType()->isPointerTy()) {
- if (op.Ty->isSignedIntegerOrEnumerationType()) {
- switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
- case LangOptions::SOB_Defined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
+ if (op.Ty->isSignedIntegerOrEnumerationType() ||
+ op.Ty->isUnsignedIntegerType()) {
+ const bool isSigned = op.Ty->isSignedIntegerOrEnumerationType();
+ const bool hasSan =
+ isSigned ? CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)
+ : CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow);
+ switch (getOverflowBehaviorConsideringType(CGF, op.Ty)) {
+ case LangOptions::OB_Wrap:
+ return Builder.CreateSub(op.LHS, op.RHS, "sub");
+ case LangOptions::OB_FWrapv:
+ if (!hasSan)
return Builder.CreateSub(op.LHS, op.RHS, "sub");
[[fallthrough]];
- case LangOptions::SOB_Undefined:
- if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
- return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
+ case LangOptions::OB_Unset:
+ if (!hasSan)
+ return isSigned ? Builder.CreateNSWSub(op.LHS, op.RHS, "sub")
+ : Builder.CreateSub(op.LHS, op.RHS, "sub");
[[fallthrough]];
- case LangOptions::SOB_Trapping:
+ case LangOptions::OB_NoWrap:
if (CanElideOverflowCheck(CGF.getContext(), op))
- return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
+ return isSigned ? Builder.CreateNSWSub(op.LHS, op.RHS, "sub")
+ : Builder.CreateSub(op.LHS, op.RHS, "sub");
return EmitOverflowCheckedBinOp(op);
}
}
@@ -4666,11 +4724,6 @@ Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
return MB.CreateSub(op.LHS, op.RHS);
}
- if (op.Ty->isUnsignedIntegerType() &&
- CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
- !CanElideOverflowCheck(CGF.getContext(), op))
- return EmitOverflowCheckedBinOp(op);
-
if (op.LHS->getType()->isFPOrFPVectorTy()) {
CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
return Builder.CreateFSub(op.LHS, op.RHS, "sub");
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index b2fe9171372d8..2c976115ee2fb 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -285,6 +285,7 @@ TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) {
case Type::BitInt:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
return TEK_Scalar;
// Complexes.
@@ -2577,6 +2578,7 @@ void CodeGenFunction::EmitVariablyModifiedType(QualType type) {
case Type::UnaryTransform:
case Type::Attributed:
case Type::BTFTagAttributed:
+ case Type::OverflowBehavior:
case Type::HLSLAttributedResource:
case Type::SubstTemplateTypeParm:
case Type::MacroQualified:
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index 3ffe999d01178..e9a8a1537da06 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -770,6 +770,10 @@ llvm::Type *CodeGenTypes::ConvertType(QualType T) {
case Type::HLSLInlineSpirv:
ResultType = CGM.getHLSLRuntime().convertHLSLSpecificType(Ty);
break;
+ case Type::OverflowBehavior:
+ ResultType =
+ ConvertType(dyn_cast<OverflowBehaviorType>(Ty)->getUnderlyingType());
+ break;
}
assert(ResultType && "Didn't convert a type?");
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 7dc2eaf1e9f75..4cbfef9558cc7 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -3954,6 +3954,7 @@ void ItaniumRTTIBuilder::BuildVTablePointer(const Type *Ty,
case Type::Builtin:
case Type::BitInt:
+ case Type::OverflowBehavior:
// GCC treats vector and complex types as fundamental types.
case Type::Vector:
case Type::ExtVector:
@@ -4310,6 +4311,9 @@ llvm::Constant *ItaniumRTTIBuilder::BuildTypeInfo(
// No fields, at least for the moment.
break;
+ case Type::OverflowBehavior:
+ break;
+
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
llvm_unreachable("HLSL doesn't support RTTI");
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index a357a8828b13d..e0320990d46b7 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6350,6 +6350,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
Args.addOptInFlag(CmdArgs, options::OPT_ffixed_point,
options::OPT_fno_fixed_point);
+ Args.addOptInFlag(CmdArgs, options::OPT_foverflow_behavior_types,
+ options::OPT_fno_overflow_behavior_types);
+
if (Arg *A = Args.getLastArg(options::OPT_fcxx_abi_EQ))
A->render(Args, CmdArgs);
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 077f4311ed729..0551ed22ffe7b 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -8328,6 +8328,10 @@ CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
ExprTy = TET->getUnderlyingExpr()->getType();
}
+ if (const OverflowBehaviorType *OBT =
+ dyn_cast<OverflowBehaviorType>(ExprTy.getCanonicalType()))
+ ExprTy = OBT->getUnderlyingType();
+
// When using the format attribute in C++, you can receive a function or an
// array that will necessarily decay to a pointer when passed to the final
// format consumer. Apply decay before type comparison.
@@ -10581,6 +10585,8 @@ struct IntRange {
T = CT->getElementType().getTypePtr();
if (const auto *AT = dyn_cast<AtomicType>(T))
T = AT->getValueType().getTypePtr();
+ if (const OverflowBehaviorType *OBT = dyn_cast<OverflowBehaviorType>(T))
+ T = OBT->getUnderlyingType().getTypePtr();
if (!C.getLangOpts().CPlusPlus) {
// For enum types in C code, use the underlying datatype.
@@ -10630,6 +10636,8 @@ struct IntRange {
T = AT->getValueType().getTypePtr();
if (const auto *ED = T->getAsEnumDecl())
T = C.getCanonicalType(ED->getIntegerType()).getTypePtr();
+ if (const OverflowBehaviorType *OBT = dyn_cast<OverflowBehaviorType>(T))
+ T = OBT->getUnderlyingType().getTypePtr();
if (const auto *EIT = dyn_cast<BitIntType>(T))
return IntRange(EIT->getNumBits(), EIT->isUnsigned());
@@ -11763,6 +11771,11 @@ static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
}
}
+ // Set context flag for overflow behavior type assignment analysis, use RAII
+ // pattern to handle nested assignments.
+ llvm::SaveAndRestore OBTAssignmentContext(
+ S.InOverflowBehaviorAssignmentContext, true);
+
AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
// Diagnose implicitly sequentially-consistent atomic assignment.
@@ -12250,6 +12263,8 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
}
}
+ CheckOverflowBehaviorTypeConversion(E, T, CC);
+
// If the we're converting a constant to an ObjC BOOL on a platform where BOOL
// is a typedef for signed char (macOS), then that constant value has to be 1
// or 0.
@@ -12582,6 +12597,15 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
IntRange TargetRange = IntRange::forTargetOfCanonicalType(Context, Target);
if (LikelySourceRange->Width > TargetRange.Width) {
+ // Check if target is a wrapping OBT - if so, don't warn about constant
+ // conversion as this type may be used intentionally with implicit
+ // truncation, especially during assignments.
+ if (const auto *TargetOBT = Target->getAs<OverflowBehaviorType>()) {
+ if (TargetOBT->isWrapKind()) {
+ return;
+ }
+ }
+
// If the source is a constant, use a default-on diagnostic.
// TODO: this should happen for bitfield stores, too.
Expr::EvalResult Result;
@@ -13254,6 +13278,36 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
<< FixItHint::CreateInsertion(getLocForEndOfToken(E->getEndLoc()), "()");
}
+bool Sema::CheckOverflowBehaviorTypeConversion(Expr *E, QualType T,
+ SourceLocation CC) {
+ QualType Source = E->getType();
+ QualType Target = T;
+
+ if (const auto *OBT = Source->getAs<OverflowBehaviorType>()) {
+ if (Target->isIntegerType() && !Target->isOverflowBehaviorType()) {
+ // Overflow behavior type is being stripped - issue warning
+ if (OBT->isUnsignedIntegerType() && OBT->isWrapKind() &&
+ Target->isUnsignedIntegerType()) {
+ DiagnoseImpCast(*this, E, T, CC,
+ diag::warn_impcast_overflow_behavior_pedantic);
+ } else {
+ unsigned DiagId = InOverflowBehaviorAssignmentContext
+ ? diag::warn_impcast_overflow_behavior_assignment
+ : diag::warn_impcast_overflow_behavior;
+ DiagnoseImpCast(*this, E, T, CC, DiagId);
+ }
+ }
+ }
+
+ if (const auto *TargetOBT = Target->getAs<OverflowBehaviorType>()) {
+ if (TargetOBT->isWrapKind()) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
// Don't diagnose in unevaluated contexts.
if (isUnevaluatedContext())
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 7c1459e320167..2ab3f9f888957 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -13998,6 +13998,10 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
// struct T { S a, b; } t = { Temp(), Temp() }
//
// we should destroy the first Temp before constructing the second.
+
+ // Set context flag for OverflowBehaviorType initialization analysis
+ llvm::SaveAndRestore OBTAssignmentContext(InOverflowBehaviorAssignmentContext,
+ true);
ExprResult Result =
ActOnFinishFullExpr(Init, VDecl->getLocation(),
/*DiscardedValue*/ false, VDecl->isConstexpr());
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index aba00dc8ff9b6..ee025e6557f7f 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -1410,6 +1410,36 @@ static QualType handleComplexIntConversion(Sema &S, ExprResult &LHS,
return ComplexType;
}
+static QualType handleOverflowBehaviorTypeConversion(Sema &S, ExprResult &LHS,
+ ExprResult &RHS,
+ bool IsCompAssign) {
+ QualType LHSType = LHS.get()->getType().getUnqualifiedType();
+ QualType RHSType = RHS.get()->getType().getUnqualifiedType();
+
+ const OverflowBehaviorType *LhsOBT = LHSType->getAs<OverflowBehaviorType>();
+ const OverflowBehaviorType *RhsOBT = RHSType->getAs<OverflowBehaviorType>();
+
+ assert(LHSType->isIntegerType() && RHSType->isIntegerType() &&
+ "Non-integer type conversion not supported for OverflowBehaviorTypes");
+
+ if (LhsOBT && RhsOBT) {
+ if (LhsOBT->getBehaviorKind() == RhsOBT->getBehaviorKind())
+ return handleIntegerConversion<doIntegralCast, doIntegralCast>(
+ S, LHS, RHS, LHSType, RHSType, IsCompAssign);
+ }
+
+ // NoWrap has precedence over Wrap; eagerly cast Wrap types to NoWrap types
+ if ((LhsOBT && !RhsOBT) || (LhsOBT && RhsOBT && !RhsOBT->isNoWrapKind())) {
+ RHS = doIntegralCast(S, RHS.get(), LHSType);
+ return LHSType;
+ }
+
+ if (!IsCompAssign)
+ LHS = doIntegralCast(S, LHS.get(), RHSType);
+
+ return RHSType;
+}
+
/// Return the rank of a given fixed point or integer type. The value itself
/// doesn't matter, but the values must be increasing with proper increasing
/// rank as described in N1169 4.1.1.
@@ -1667,14 +1697,20 @@ QualType Sema::UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
LHSType = AtomicLHS->getValueType();
// If both types are identical, no conversion is needed.
- if (Context.hasSameType(LHSType, RHSType))
+ if (Context.hasSameType(LHSType, RHSType)) {
return Context.getCommonSugaredType(LHSType, RHSType);
+ }
// If either side is a non-arithmetic type (e.g. a pointer), we are done.
// The caller can deal with this (e.g. pointer + int).
if (!LHSType->isArithmeticType() || !RHSType->isArithmeticType())
return QualType();
+ if (LHSType->isOverflowBehaviorType() || RHSType->isOverflowBehaviorType()) {
+ return handleOverflowBehaviorTypeConversion(
+ *this, LHS, RHS, ACK == ArithConvKind::CompAssign);
+ }
+
// Apply unary and bitfield promotions to the LHS's type.
QualType LHSUnpromotedType = LHSType;
if (Context.isPromotableIntegerType(LHSType))
@@ -1919,16 +1955,33 @@ ExprResult Sema::CreateGenericSelectionExpr(
for (unsigned i = 0; i < NumAssocs; ++i) {
if (!Types[i])
DefaultIndex = i;
- else if (ControllingExpr &&
- Context.typesAreCompatible(
- ControllingExpr->getType().getCanonicalType(),
- Types[i]->getType()))
- CompatIndices.push_back(i);
- else if (ControllingType &&
- Context.typesAreCompatible(
- ControllingType->getType().getCanonicalType(),
- Types[i]->getType()))
- CompatIndices.push_back(i);
+ else {
+ bool Compatible;
+ QualType ControllingQT =
+ ControllingExpr ? ControllingExpr->getType().getCanonicalType()
+ : ControllingType->getType().getCanonicalType();
+ QualType AssocQT = Types[i]->getType();
+
+ const auto *ControllingOBT = ControllingQT->getAs<OverflowBehaviorType>();
+ const auto *AssocOBT =
+ AssocQT.getCanonicalType()->getAs<OverflowBehaviorType>();
+
+ if (ControllingOBT || AssocOBT) {
+ if (ControllingOBT && AssocOBT) {
+ if (ControllingOBT->getBehaviorKind() == AssocOBT->getBehaviorKind())
+ Compatible =
+ Context.typesAreCompatible(ControllingOBT->getUnderlyingType(),
+ AssocOBT->getUnderlyingType());
+ else
+ Compatible = false;
+ } else
+ Compatible = false;
+ } else
+ Compatible = Context.typesAreCompatible(ControllingQT, AssocQT);
+
+ if (Compatible)
+ CompatIndices.push_back(i);
+ }
}
auto GetControllingRangeAndType = [](Expr *ControllingExpr,
@@ -4541,6 +4594,7 @@ static void captureVariablyModifiedType(ASTContext &Context, QualType T,
case Type::UnaryTransform:
case Type::Attributed:
case Type::BTFTagAttributed:
+ case Type::OverflowBehavior:
case Type::HLSLAttributedResource:
case Type::SubstTemplateTypeParm:
case Type::MacroQualified:
@@ -9129,6 +9183,25 @@ static AssignConvertType checkPointerTypesForAssignment(Sema &S,
// C99 6.5.16.1p1 (constraint 3): both operands are pointers to qualified or
// unqualified versions of compatible types, ...
QualType ltrans = QualType(lhptee, 0), rtrans = QualType(rhptee, 0);
+
+ if (ltrans->isOverflowBehaviorType() || rtrans->isOverflowBehaviorType()) {
+ if (!S.Context.hasSameType(ltrans, rtrans)) {
+ QualType LUnderlying =
+ ltrans->isOverflowBehaviorType()
+ ? ltrans->castAs<OverflowBehaviorType>()->getUnderlyingType()
+ : ltrans;
+ QualType RUnderlying =
+ rtrans->isOverflowBehaviorType()
+ ? rtrans->castAs<OverflowBehaviorType>()->getUnderlyingType()
+ : rtrans;
+
+ if (S.Context.hasSameType(LUnderlying, RUnderlying))
+ return AssignConvertType::IncompatiblePointerDiscardsOverflowBehavior;
+
+ return AssignConvertType::IncompatiblePointer;
+ }
+ }
+
if (!S.Context.typesAreCompatible(ltrans, rtrans)) {
// Check if the pointee types are compatible ignoring the sign.
// We explicitly check for char so that we catch "char" vs
@@ -14340,6 +14413,8 @@ static QualType CheckIncrementDecrementOperand(Sema &S, Expr *Op,
// C99 6.5.2.4p2, 6.5.6p2
if (!checkArithmeticOpPointerOperand(S, OpLoc, Op))
return QualType();
+ } else if (ResType->isOverflowBehaviorType()) {
+ // OK!
} else if (ResType->isObjCObjectPointerType()) {
// On modern runtimes, ObjC pointer arithmetic is forbidden.
// Otherwise, we just need a complete type.
@@ -17206,6 +17281,12 @@ bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
llvm_unreachable("unknown error case for discarding qualifiers!");
// fallthrough
}
+ case AssignConvertType::IncompatiblePointerDiscardsOverflowBehavior:
+ if (SrcType->isArrayType())
+ SrcType = Context.getArrayDecayedType(SrcType);
+
+ DiagKind = diag::ext_typecheck_convert_discards_overflow_behavior;
+ break;
case AssignConvertType::CompatiblePointerDiscardsQualifiers:
// If the qualifiers lost were because we were applying the
// (deprecated) C++ conversion from a string literal to a char*
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index c97129336736b..50c9958b8113f 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -9744,6 +9744,16 @@ static void DiagnoseNarrowingInInitList(Sema &S,
case NK_Constant_Narrowing: {
// A constant value was narrowed.
+
+ // Overflow behavior destination types with a 'wrap' kind can elide
+ // narrowing diagnostics.
+ QualType DestType = EntityType.getNonReferenceType();
+ if (const auto *DestOBT = DestType->getAs<OverflowBehaviorType>()) {
+ if (DestOBT->isWrapKind()) {
+ return;
+ }
+ }
+
MakeDiag(EntityType.getNonReferenceType() != EntityType,
diag::ext_init_list_constant_narrowing,
diag::ext_init_list_constant_narrowing_const_reference,
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 54918c560b655..7cdd5da50e4d7 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -3303,6 +3303,8 @@ addAssociatedClassesAndNamespaces(AssociatedLookup &Result, QualType Ty) {
// Inline SPIR-V types are treated as fundamental types.
case Type::HLSLInlineSpirv:
break;
+ case Type::OverflowBehavior:
+ T = cast<OverflowBehaviorType>(T)->getUnderlyingType().getTypePtr();
}
if (Queue.empty())
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 941542247e240..5f62194d25dcb 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -117,6 +117,11 @@ CompareQualificationConversions(Sema &S,
const StandardConversionSequence& SCS1,
const StandardConversionSequence& SCS2);
+static ImplicitConversionSequence::CompareKind
+CompareOverflowBehaviorConversions(Sema &S,
+ const StandardConversionSequence &SCS1,
+ const StandardConversionSequence &SCS2);
+
static ImplicitConversionSequence::CompareKind
CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
const StandardConversionSequence& SCS1,
@@ -2228,6 +2233,12 @@ static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
StandardConversionSequence &SCS,
bool CStyle);
+static bool tryOverflowBehaviorTypeConversion(Sema &S, Expr *From,
+ QualType ToType,
+ bool InOverloadResolution,
+ StandardConversionSequence &SCS,
+ bool CStyle);
+
/// IsStandardConversion - Determines whether there is a standard
/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
/// expression From to the type ToType. Standard conversion sequences
@@ -2418,9 +2429,16 @@ static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
// Complex promotion (Clang extension)
SCS.Second = ICK_Complex_Promotion;
FromType = ToType.getUnqualifiedType();
+ } else if (S.IsOverflowBehaviorTypePromotion(FromType, ToType)) {
+ // OverflowBehaviorType promotions
+ SCS.Second = ICK_Integral_Promotion;
+ FromType = ToType.getUnqualifiedType();
+ } else if (S.IsOverflowBehaviorTypeConversion(FromType, ToType)) {
+ // OverflowBehaviorType conversions
+ SCS.Second = ICK_Integral_Conversion;
+ FromType = ToType.getUnqualifiedType();
} else if (ToType->isBooleanType() &&
- (FromType->isArithmeticType() ||
- FromType->isAnyPointerType() ||
+ (FromType->isArithmeticType() || FromType->isAnyPointerType() ||
FromType->isBlockPointerType() ||
FromType->isMemberPointerType())) {
// Boolean conversions (C++ 4.12).
@@ -2486,6 +2504,9 @@ static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
// tryAtomicConversion has updated the standard conversion sequence
// appropriately.
return true;
+ } else if (tryOverflowBehaviorTypeConversion(
+ S, From, ToType, InOverloadResolution, SCS, CStyle)) {
+ return true;
} else if (ToType->isEventT() &&
From->isIntegerConstantExpr(S.getASTContext()) &&
From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
@@ -2836,6 +2857,41 @@ bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
ToComplex->getElementType());
}
+bool Sema::IsOverflowBehaviorTypePromotion(QualType FromType, QualType ToType) {
+ if (!getLangOpts().OverflowBehaviorTypes)
+ return false;
+
+ if (!FromType->isOverflowBehaviorType() || !ToType->isOverflowBehaviorType())
+ return false;
+
+ return Context.getTypeSize(FromType) < Context.getTypeSize(ToType);
+}
+
+bool Sema::IsOverflowBehaviorTypeConversion(QualType FromType,
+ QualType ToType) {
+ if (!getLangOpts().OverflowBehaviorTypes)
+ return false;
+
+ if (FromType->isOverflowBehaviorType() && !ToType->isOverflowBehaviorType()) {
+ // Don't allow implicit conversion from OverflowBehaviorType to scoped enum
+ if (const EnumType *ToEnumType = ToType->getAs<EnumType>()) {
+ const EnumDecl *ToED =
+ ToEnumType->getOriginalDecl()->getDefinitionOrSelf();
+ if (ToED->isScoped())
+ return false;
+ }
+ return true;
+ }
+
+ if (!FromType->isOverflowBehaviorType() && ToType->isOverflowBehaviorType())
+ return true;
+
+ if (FromType->isOverflowBehaviorType() && ToType->isOverflowBehaviorType())
+ return Context.getTypeSize(FromType) > Context.getTypeSize(ToType);
+
+ return false;
+}
+
/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
/// the pointer type FromPtr to a pointer to type ToPointee, with the
/// same type qualifiers as FromPtr has on its pointee type. ToType,
@@ -3868,6 +3924,30 @@ static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
return true;
}
+static bool tryOverflowBehaviorTypeConversion(Sema &S, Expr *From,
+ QualType ToType,
+ bool InOverloadResolution,
+ StandardConversionSequence &SCS,
+ bool CStyle) {
+ const OverflowBehaviorType *ToOBT = ToType->getAs<OverflowBehaviorType>();
+ if (!ToOBT)
+ return false;
+
+ StandardConversionSequence InnerSCS;
+ if (!IsStandardConversion(S, From, ToOBT->getUnderlyingType(),
+ InOverloadResolution, InnerSCS, CStyle,
+ /*AllowObjCWritebackConversion=*/false))
+ return false;
+
+ SCS.Second = InnerSCS.Second;
+ SCS.setToType(1, InnerSCS.getToType(1));
+ SCS.Third = InnerSCS.Third;
+ SCS.QualificationIncludesObjCLifetime =
+ InnerSCS.QualificationIncludesObjCLifetime;
+ SCS.setToType(2, InnerSCS.getToType(2));
+ return true;
+}
+
static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
CXXConstructorDecl *Constructor,
QualType Type) {
@@ -4653,6 +4733,10 @@ CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
= CompareQualificationConversions(S, SCS1, SCS2))
return QualCK;
+ if (ImplicitConversionSequence::CompareKind ObtCK =
+ CompareOverflowBehaviorConversions(S, SCS1, SCS2))
+ return ObtCK;
+
if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
// C++ [over.ics.rank]p3b4:
// -- S1 and S2 are reference bindings (8.5.3), and the types to
@@ -4765,6 +4849,25 @@ CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
return ImplicitConversionSequence::Indistinguishable;
}
+/// CompareOverflowBehaviorConversions - Compares two standard conversion
+/// sequences to determine whether they can be ranked based on their
+/// OverflowBehaviorType's underlying type.
+static ImplicitConversionSequence::CompareKind
+CompareOverflowBehaviorConversions(Sema &S,
+ const StandardConversionSequence &SCS1,
+ const StandardConversionSequence &SCS2) {
+
+ if (SCS1.getFromType()->isOverflowBehaviorType() &&
+ SCS1.getToType(2)->isOverflowBehaviorType())
+ return ImplicitConversionSequence::Better;
+
+ if (SCS2.getFromType()->isOverflowBehaviorType() &&
+ SCS2.getToType(2)->isOverflowBehaviorType())
+ return ImplicitConversionSequence::Worse;
+
+ return ImplicitConversionSequence::Indistinguishable;
+}
+
/// CompareQualificationConversions - Compares two standard conversion
/// sequences to determine whether they can be ranked based on their
/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 58dae32569bcc..12200402685ca 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -6417,6 +6417,11 @@ bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
return Visit(T->getValueType());
}
+bool UnnamedLocalNoLinkageFinder::VisitOverflowBehaviorType(
+ const OverflowBehaviorType *T) {
+ return Visit(T->getUnderlyingType());
+}
+
bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
return false;
}
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index cce40c0c91f95..5807e80a2f91e 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -2546,6 +2546,7 @@ static TemplateDeductionResult DeduceTemplateArgumentsByTypeMatch(
case Type::ArrayParameter:
case Type::HLSLAttributedResource:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
// No template argument deduction for these types
return TemplateDeductionResult::Success;
@@ -7132,6 +7133,7 @@ MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
case Type::Pipe:
case Type::BitInt:
case Type::HLSLInlineSpirv:
+ case Type::OverflowBehavior:
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define DEPENDENT_TYPE(Class, Base)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 0f655d7f684a5..43a391db39883 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -300,6 +300,14 @@ namespace {
return sema.Context.getBTFTagAttributedType(BTFAttr, WrappedType);
}
+ /// Get a OverflowBehaviorType type for the overflow_behavior type
+ /// attribute.
+ QualType
+ getOverflowBehaviorType(OverflowBehaviorType::OverflowBehaviorKind Kind,
+ QualType UnderlyingType) {
+ return sema.Context.getOverflowBehaviorType(Kind, UnderlyingType);
+ }
+
/// Completely replace the \c auto in \p TypeWithAuto by
/// \p Replacement. Also replace \p TypeWithAuto in \c TypeAttrPair if
/// necessary.
@@ -5888,6 +5896,9 @@ namespace {
void VisitBTFTagAttributedTypeLoc(BTFTagAttributedTypeLoc TL) {
Visit(TL.getWrappedLoc());
}
+ void VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc TL) {
+ Visit(TL.getWrappedLoc());
+ }
void VisitHLSLAttributedResourceTypeLoc(HLSLAttributedResourceTypeLoc TL) {
Visit(TL.getWrappedLoc());
fillHLSLAttributedResourceTypeLoc(TL, State);
@@ -6182,6 +6193,9 @@ namespace {
void VisitBTFTagAttributedTypeLoc(BTFTagAttributedTypeLoc TL) {
// nothing
}
+ void VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc TL) {
+ // nothing
+ }
void VisitAdjustedTypeLoc(AdjustedTypeLoc TL) {
// nothing
}
@@ -6632,6 +6646,90 @@ static void HandleAddressSpaceTypeAttribute(QualType &Type,
}
}
+static void HandleOverflowBehaviorAttr(QualType &Type, const ParsedAttr &Attr,
+ TypeProcessingState &State) {
+ Sema &S = State.getSema();
+
+ // Check for -foverflow-behavior-types
+ if (!S.getLangOpts().OverflowBehaviorTypes) {
+ S.Diag(Attr.getLoc(), diag::warn_overflow_behavior_attribute_disabled)
+ << Attr << 1;
+ Attr.setInvalid();
+ return;
+ }
+
+ // Check the number of attribute arguments.
+ if (Attr.getNumArgs() != 1) {
+ S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
+ << Attr << 1;
+ Attr.setInvalid();
+ return;
+ }
+
+ // Check that the underlying type is an integer type
+ if (!Type->isIntegerType()) {
+ S.Diag(Attr.getLoc(), diag::warn_overflow_behavior_non_integer_type)
+ << Attr << Type.getAsString();
+ Attr.setInvalid();
+ return;
+ }
+
+ StringRef KindName = "";
+ IdentifierInfo *Ident = nullptr;
+
+ if (Attr.isArgIdent(0)) {
+ Ident = Attr.getArgAsIdent(0)->getIdentifierInfo();
+ KindName = Ident->getName();
+ }
+
+ // Support identifier or string argument types. Failure to provide one of
+ // these two types results in a diagnostic that hints towards using string
+ // arguments (either "wrap" or "no_wrap") as this is the most common use
+ // pattern.
+ if (!Ident) {
+ auto *Str = dyn_cast<StringLiteral>(Attr.getArgAsExpr(0));
+ if (Str)
+ KindName = Str->getString();
+ else {
+ S.Diag(Attr.getLoc(), diag::err_attribute_argument_type)
+ << Attr << AANT_ArgumentString;
+ Attr.setInvalid();
+ return;
+ }
+ }
+
+ OverflowBehaviorType::OverflowBehaviorKind Kind;
+ if (KindName == "wrap") {
+ Kind = OverflowBehaviorType::OverflowBehaviorKind::Wrap;
+ } else if (KindName == "no_wrap") {
+ Kind = OverflowBehaviorType::OverflowBehaviorKind::NoWrap;
+ } else {
+ S.Diag(Attr.getLoc(), diag::err_overflow_behavior_unknown_ident)
+ << KindName << Attr;
+ Attr.setInvalid();
+ return;
+ }
+
+ // Check for conflicting overflow behavior attributes
+ if (const auto *ExistingOBT = Type->getAs<OverflowBehaviorType>()) {
+ OverflowBehaviorType::OverflowBehaviorKind ExistingKind =
+ ExistingOBT->getBehaviorKind();
+ if (ExistingKind != Kind) {
+ // Conflicting attributes - issue warning and let no_wrap take precedence
+ S.Diag(Attr.getLoc(),
+ diag::warn_conflicting_overflow_behavior_attributes);
+ if (Kind == OverflowBehaviorType::OverflowBehaviorKind::NoWrap) {
+ // Current is no_wrap, replace existing
+ Type = State.getOverflowBehaviorType(Kind,
+ ExistingOBT->getUnderlyingType());
+ }
+ return;
+ }
+ } else {
+ Type = State.getOverflowBehaviorType(Kind, Type);
+ }
+}
+
/// handleObjCOwnershipTypeAttr - Process an objc_ownership
/// attribute on the specified type.
///
@@ -8974,6 +9072,10 @@ static void processTypeAttrs(TypeProcessingState &state, QualType &type,
if (TAL == TAL_DeclChunk)
HandleLifetimeCaptureByAttr(state, type, attr);
break;
+ case ParsedAttr::AT_OverflowBehavior:
+ HandleOverflowBehaviorAttr(type, attr, state);
+ attr.setUsedAsTypeAttr();
+ break;
case ParsedAttr::AT_NoDeref: {
// FIXME: `noderef` currently doesn't work correctly in [[]] syntax.
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 0587a7decbd8d..a5a694f8a5c22 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -7657,6 +7657,27 @@ QualType TreeTransform<Derived>::TransformBTFTagAttributedType(
llvm_unreachable("Unexpected TreeTransform for BTFTagAttributedType");
}
+template <typename Derived>
+QualType TreeTransform<Derived>::TransformOverflowBehaviorType(
+ TypeLocBuilder &TLB, OverflowBehaviorTypeLoc TL) {
+ const OverflowBehaviorType *OldTy = TL.getTypePtr();
+ QualType InnerTy = getDerived().TransformType(TLB, TL.getWrappedLoc());
+ if (InnerTy.isNull())
+ return QualType();
+
+ QualType Result = TL.getType();
+ if (getDerived().AlwaysRebuild() || InnerTy != OldTy->getUnderlyingType()) {
+ Result = SemaRef.Context.getOverflowBehaviorType(OldTy->getBehaviorKind(),
+ InnerTy);
+ if (Result.isNull())
+ return QualType();
+ }
+
+ OverflowBehaviorTypeLoc NewTL = TLB.push<OverflowBehaviorTypeLoc>(Result);
+ NewTL.initializeLocal(SemaRef.Context, TL.getAttrLoc());
+ return Result;
+}
+
template <typename Derived>
QualType TreeTransform<Derived>::TransformHLSLAttributedResourceType(
TypeLocBuilder &TLB, HLSLAttributedResourceTypeLoc TL) {
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 1b3a8b13f1fb1..6dae7fd6a382c 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7477,6 +7477,10 @@ void TypeLocReader::VisitBTFTagAttributedTypeLoc(BTFTagAttributedTypeLoc TL) {
// Nothing to do.
}
+void TypeLocReader::VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc TL) {
+ // Nothing to do.
+}
+
void TypeLocReader::VisitHLSLAttributedResourceTypeLoc(
HLSLAttributedResourceTypeLoc TL) {
// Nothing to do.
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 8e219e54bf251..7f67cd336557f 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -604,6 +604,10 @@ void TypeLocWriter::VisitBTFTagAttributedTypeLoc(BTFTagAttributedTypeLoc TL) {
// Nothing to do.
}
+void TypeLocWriter::VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc TL) {
+ // Nothing to do.
+}
+
void TypeLocWriter::VisitHLSLAttributedResourceTypeLoc(
HLSLAttributedResourceTypeLoc TL) {
// Nothing to do.
diff --git a/clang/test/CodeGen/mangle-ms-overflow-behavior.cpp b/clang/test/CodeGen/mangle-ms-overflow-behavior.cpp
new file mode 100644
index 0000000000000..da49d0c540a82
--- /dev/null
+++ b/clang/test/CodeGen/mangle-ms-overflow-behavior.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -emit-llvm %s -o - -fms-extensions -triple=x86_64-pc-win32 -foverflow-behavior-types | FileCheck %s
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap int_wrap;
+
+// CHECK: define dso_local void @"?test_wrap_int@@YAXU?$ObtWrap_ at H@__clang@@@Z"
+void test_wrap_int(int_wrap x) {}
+
+// CHECK: define dso_local void @"?test_no_wrap_int@@YAXU?$ObtNoWrap_ at H@__clang@@@Z"
+void test_no_wrap_int(int __no_wrap y) {}
diff --git a/clang/test/CodeGen/overflow-behavior-types-extensions.c b/clang/test/CodeGen/overflow-behavior-types-extensions.c
new file mode 100644
index 0000000000000..6e05a2db41161
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types-extensions.c
@@ -0,0 +1,50 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types -std=c2x %s -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __nowrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap w_int;
+typedef int __nowrap nw_int;
+
+// CHECK-LABEL: define {{.*}} @generic_selection_test_nomatch
+int generic_selection_test_nomatch(int x) {
+ // CHECK: ret i32 3
+ return _Generic(x, w_int: 1, nw_int: 2, default: 3);
+}
+
+// CHECK-LABEL: define {{.*}} @generic_selection_test_obtmatch
+int generic_selection_test_obtmatch(w_int x) {
+ // CHECK: ret i32 1
+ return _Generic(x, w_int: 1, nw_int: 2, default: 3);
+}
+
+// CHECK-LABEL: define {{.*}} @generic_selection_test_obt_nomatch
+int generic_selection_test_obt_nomatch(w_int x) {
+ // CHECK: ret i32 3
+ return _Generic(x, int: 1, char: 2, default: 3);
+}
+
+// CHECK-LABEL: define {{.*}} @signed_bitint_test
+void signed_bitint_test(_BitInt(4) __nowrap a, _BitInt(8) __nowrap b, _BitInt(99) __wrap c) {
+ // CHECK: call { i4, i1 } @llvm.sadd.with.overflow.i4(i4
+ (a + 1);
+
+ // CHECK: call { i8, i1 } @llvm.sadd.with.overflow.i8(i8
+ (b + 1);
+
+ // CHECK: add i99 {{.*}}, 1
+ (c + 1);
+}
+
+// CHECK-LABEL: define {{.*}} @unsigned_bitint_test
+void unsigned_bitint_test(unsigned _BitInt(4) __nowrap a, unsigned _BitInt(8) __nowrap b, unsigned _BitInt(99) __wrap c) {
+ // CHECK: call { i4, i1 } @llvm.uadd.with.overflow.i4(i4
+ (a + 1);
+
+ // CHECK: call { i8, i1 } @llvm.uadd.with.overflow.i8(i8
+ (b + 1);
+
+ // CHECK: add i99 {{.*}}, 1
+ (c + 1);
+}
+
diff --git a/clang/test/CodeGen/overflow-behavior-types-operators.cpp b/clang/test/CodeGen/overflow-behavior-types-operators.cpp
new file mode 100644
index 0000000000000..8049ece3af696
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types-operators.cpp
@@ -0,0 +1,70 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %s -foverflow-behavior-types \
+// RUN: -fsanitize=signed-integer-overflow -emit-llvm -o - -std=c++14 | FileCheck %s
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __nowrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap wrap_int;
+typedef int __nowrap nowrap_int;
+typedef unsigned int __wrap u_wrap_int;
+typedef unsigned int __nowrap u_nowrap_int;
+
+//===----------------------------------------------------------------------===//
+// Compound Assignment Operators
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: define {{.*}} @_Z28compound_assignment_operatorv
+void compound_assignment_operator() {
+ wrap_int a = 1;
+ // CHECK: add i32
+ a += 1;
+
+ nowrap_int b = 1;
+ // CHECK: llvm.sadd.with.overflow.i32
+ b += 1;
+
+ u_wrap_int c = 1;
+ // CHECK: sub i32
+ c -= 1;
+
+ u_nowrap_int d = 1;
+ // CHECK: llvm.usub.with.overflow.i32
+ d -= 1;
+
+ wrap_int e = 2;
+ // CHECK: mul i32
+ e *= 2;
+
+ nowrap_int f = 2;
+ // CHECK: llvm.smul.with.overflow.i32
+ f *= 2;
+}
+
+//===----------------------------------------------------------------------===//
+// Bitwise and Shift Operators
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: define {{.*}} @_Z27bitwise_and_shift_operatorsv
+void bitwise_and_shift_operators() {
+ wrap_int a = 1;
+ // CHECK: shl i32
+ // No overflow check for shifts
+ a <<= 1;
+
+ nowrap_int b = 1;
+ // CHECK: ashr i32
+ // No overflow check for shifts
+ b >>= 1;
+
+ wrap_int c = 1;
+ // CHECK: and i32
+ c &= 1;
+
+ nowrap_int d = 1;
+ // CHECK: xor i32
+ d ^= 1;
+
+ u_wrap_int e = 1;
+ // CHECK: or i32
+ e |= 1;
+}
diff --git a/clang/test/CodeGen/overflow-behavior-types-promotions.cpp b/clang/test/CodeGen/overflow-behavior-types-promotions.cpp
new file mode 100644
index 0000000000000..795439d2578c3
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types-promotions.cpp
@@ -0,0 +1,50 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %s -foverflow-behavior-types \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow -emit-llvm -o - -std=c++14 | FileCheck %s
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __nowrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap wrap_int;
+typedef char __wrap wrap_char;
+typedef int __nowrap nowrap_int;
+typedef unsigned int __wrap u_wrap_int;
+typedef unsigned int __nowrap u_nowrap_int;
+
+// CHECK-LABEL: define {{.*}} @_Z30conditional_operator_promotionbU11ObtWrap_cU13ObtNoWrap_ii
+void conditional_operator_promotion(bool cond, wrap_char w, nowrap_int nw, int i) {
+ // OBT wins over regular integer.
+ // CHECK: cond.end:
+ // CHECK-NEXT: %cond1 = phi i8
+ // CHECK-NEXT: store i8 %cond1, ptr %r1
+ // CHECK-NEXT: %{{.*}} = load i8, ptr %r1
+ // CHECK-NEXT: add i8
+ auto r1 = cond ? w : i;
+ (void)(r1 + 2147483647);
+
+ // nowrap wins over wrap.
+ // CHECK: cond.end6:
+ // CHECK-NEXT: %cond7 = phi i32
+ // CHECK-NEXT: store i32 %cond7, ptr %r2
+ // CHECK-NEXT: %{{.*}} = load i32, ptr %r2
+ // CHECK-NEXT: call { i32, i1 } @llvm.sadd.with.overflow.i32
+ auto r2 = cond ? w : nw;
+ (void)(r2 + 2147483647);
+}
+
+// CHECK-LABEL: define {{.*}} @_Z20promotion_rules_testU11ObtWrap_iU13ObtNoWrap_iU11ObtWrap_jU13ObtNoWrap_j
+void promotion_rules_test(wrap_int sw, nowrap_int snw, u_wrap_int uw, u_nowrap_int unw) {
+ // Unsigned is favored over signed for same-behavior OBTs.
+ // CHECK: add i32
+ auto r1 = sw + uw;
+ (void)r1;
+
+ // nowrap is favored over wrap. Result is unsigned nowrap.
+ // CHECK: call { i32, i1 } @llvm.uadd.with.overflow.i32
+ auto r2 = sw + unw;
+ (void)r2;
+
+ // nowrap is favored over wrap. Result is signed nowrap.
+ // CHECK: call { i32, i1 } @llvm.sadd.with.overflow.i32
+ auto r3 = uw + snw;
+ (void)r3;
+}
diff --git a/clang/test/CodeGen/overflow-behavior-types-scl.c b/clang/test/CodeGen/overflow-behavior-types-scl.c
new file mode 100644
index 0000000000000..2abf0cb2fbbb7
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types-scl.c
@@ -0,0 +1,43 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %t/test.c -fsanitize-ignorelist=%t/sio.scl -foverflow-behavior-types -fsanitize=signed-integer-overflow -emit-llvm -o - | FileCheck %s --check-prefix=SIO
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %t/test.c -fsanitize-ignorelist=%t/uio.scl -foverflow-behavior-types -fsanitize=unsigned-integer-overflow -emit-llvm -o - | FileCheck %s --check-prefix=UIO
+
+//--- sio.scl
+[signed-integer-overflow]
+# ignore signed-integer-overflow instrumentation across all types
+type:*
+
+//--- uio.scl
+[unsigned-integer-overflow]
+# ignore unsigned-integer-overflow instrumentation across all types
+type:*
+
+//--- test.c
+#define __wrap __attribute__((overflow_behavior("wrap")))
+#define __nowrap __attribute__((overflow_behavior("no_wrap")))
+
+// SIO-LABEL: define {{.*}} @foo
+// UIO-LABEL: define {{.*}} @foo
+void foo(void) {
+ // SIO-LABEL: load volatile i32, ptr @a, align 4
+ volatile extern int a;
+ volatile extern char b;
+ volatile extern char __nowrap c; // nowrap has precedence over scl entries
+
+ // SIO: add nsw i32
+ (a + 1);
+ // SIO: add nsw i32
+ (b + 1);
+ // SIO: @llvm.sadd.with.overflow.i8
+ (c + 1);
+
+ // UIO-LABEL: load volatile i32, ptr @d, align 4
+ volatile extern unsigned int d;
+ volatile extern unsigned short __nowrap e;
+ // UIO: add i32
+ (d + 1);
+ // UIO: @llvm.uadd.with.overflow.i16
+ (e + 1);
+}
diff --git a/clang/test/CodeGen/overflow-behavior-types.c b/clang/test/CodeGen/overflow-behavior-types.c
new file mode 100644
index 0000000000000..bc01f4184fb8d
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types.c
@@ -0,0 +1,148 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow,implicit-signed-integer-truncation,implicit-unsigned-integer-truncation \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s -ftrapv \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow,implicit-signed-integer-truncation,implicit-unsigned-integer-truncation \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s \
+// RUN: -ftrapv -ftrapv-handler OVERFLOW_HANDLER \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=TRAPV-HANDLER
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s -fwrapv \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow,implicit-signed-integer-truncation,implicit-unsigned-integer-truncation \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s \
+// RUN: -fsanitize-undefined-ignore-overflow-pattern=all \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow,implicit-signed-integer-truncation,implicit-unsigned-integer-truncation \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=EXCL
+
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -foverflow-behavior-types %s \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=NOSAN
+
+#define __wrap __attribute__((overflow_behavior("wrap")))
+#define __nowrap __attribute__((overflow_behavior("no_wrap")))
+
+// DEFAULT-LABEL: define {{.*}} @test1
+// TRAPV-HANDLER-LABEL: define {{.*}} @test1
+// NOSAN-LABEL: define {{.*}} @test1
+void test1(int __wrap a, int __nowrap b) {
+ // DEFAULT: add i32
+ // TRAPV-HANDLER: add i32
+ // NOSAN: add i32
+ (a + 1);
+
+ // DEFAULT: llvm.sadd.with.overflow.i32
+ // TRAPV-HANDLER: %[[T0:.*]] = load i32, ptr %b
+ // TRAPV-HANDLER: call {{.*}} @OVERFLOW_HANDLER(i64 %[[T0]]
+ // NOSAN: %[[T0:.*]] = load i32, ptr %b
+ // NOSAN-NEXT: %[[T1:.*]] = call {{.*}} @llvm.sadd.with.overflow.i32(i32 %[[T0]]
+ // NOSAN: %[[OF:.*]] = extractvalue {{.*}} %[[T1]], 1
+ // NOSAN-NEXT: %[[XOR:.*]] = xor i1 %[[OF]]
+ // NOSAN-NEXT: br i1 %[[XOR]]{{.*}}cont, label %[[TRAP:.*]], !prof
+ // NOSAN: [[TRAP]]:
+ // NOSAN-NEXT: call void @llvm.ubsantrap
+ (b + 1);
+
+ // DEFAULT: sub i32 0
+ (-a);
+
+ // DEFAULT: llvm.ssub.with.overflow.i32
+ (-b);
+
+ // DEFAULT: add i32
+ a++;
+ // DEFAULT: llvm.sadd.with.overflow.i32
+ b++;
+
+ // DEFAULT: add i32
+ ++a;
+ // DEFAULT: llvm.sadd.with.overflow.i32
+ ++b;
+
+ volatile extern int divisor;
+ // DEFAULT: %[[T0:.*]] = load i32, ptr %a
+ // DEFAULT-NEXT: %[[T1:.*]] = load volatile i32, ptr @divisor
+ // DEFAULT-NOT: br {{.*}} %handler.divrem_overflow
+ // DEFAULT: sdiv i32 %[[T0]], %[[T1]]
+ a/divisor;
+
+ // DEFAULT: %[[T0:.*]] = load i32, ptr %b
+ // DEFAULT-NEXT: %[[T1:.*]] = load volatile i32, ptr @divisor
+ // DEFAULT: br {{.*}} %handler.divrem_overflow
+ b/divisor;
+}
+
+// DEFAULT-LABEL: define {{.*}} @test2
+void test2(unsigned char __wrap a, unsigned char __nowrap b) {
+ // DEFAULT: add i8
+ (a + 1);
+ // DEFAULT: llvm.uadd.with.overflow.i8
+ (b + 1);
+
+ // DEFAULT: %[[T0:.*]] = load volatile i64, ptr @big
+ // DEFAULT: %[[TRUNC1:.*]] = icmp eq i64 {{.*}} %[[T0]]
+ // DEFAULT-NOT: br i1 %[[TRUNC1]], {{.*}} %handler.implicit_conversion
+ volatile extern unsigned long long big;
+ a = big;
+
+ // DEFAULT: %[[T1:.*]] = load volatile i64, ptr @big
+ // DEFAULT: %[[TRUNC2:.*]] = icmp eq i64 {{.*}} %[[T1]]
+ // DEFAULT: br i1 %[[TRUNC2]], {{.*}} %handler.implicit_conversion
+ b = big;
+}
+
+// DEFAULT-LABEL: define {{.*}} @test3
+void test3(void) {
+ volatile extern char __wrap a;
+ volatile extern short __wrap b;
+ // less-than-int arithmetic is possible when one or more wrapping types are
+ // present. When both operands are wrapping types, the larger of the two
+ // types should be used as the result of the arithmetic.
+
+ // DEFAULT: add i16
+ (a + b);
+
+ // nowrap has precedence over wrap, regardless of bit widths
+ volatile extern unsigned long long __wrap c;
+ volatile extern char __nowrap d;
+
+ // DEFAULT: %[[T0:.*]] = load volatile i64, ptr @c
+ // DEFAULT: %[[TRUNC1:.*]] = icmp eq i64 {{.*}} %[[T0]]
+ // DEFAULT: br i1 %[[TRUNC1]]
+ // DEFAULT: %[[T1:.*]] = load volatile i8, ptr @d
+ // DEFAULT-NEXT: @llvm.sadd.with.overflow.i8
+ (c + d);
+
+ volatile extern int __nowrap e;
+ volatile extern unsigned int __wrap f;
+
+ // DEFAULT: @llvm.ssub.with.overflow.i32
+ (e - f);
+}
+
+typedef int __attribute__((overflow_behavior(wrap))) wrap_int;
+typedef int __attribute__((overflow_behavior(no_wrap))) nowrap_int;
+// DEFAULT-LABEL: define {{.*}} @typedefs
+void typedefs(nowrap_int a, wrap_int b) {
+ // DEFAULT: llvm.sadd.with.overflow.i32
+ (a + 100);
+
+ // DEFAULT: add i32
+ (b + 100);
+}
+
+// EXCL-LABEL: define {{.*}} @ignored_patterns
+void ignored_patterns(unsigned long __attribute__((overflow_behavior(no_wrap))) a) {
+ // EXCL: %[[T0:.*]] = load i64, ptr %a.addr
+ // EXCL-NEXT: add i64 %[[T0]], -1
+ while (a--) { /*...*/ }
+
+ // EXCL: %[[T1:.*]] = load i64, ptr %a.addr
+ // EXCL: %[[T2:.*]] = load volatile i64, ptr %b
+ // EXCL-NEXT: add i64 %[[T1]], %[[T2]]
+ volatile unsigned long __attribute__((overflow_behavior(no_wrap))) b;
+ if (a + b < a) { /*...*/ }
+}
diff --git a/clang/test/CodeGen/overflow-behavior-types.cpp b/clang/test/CodeGen/overflow-behavior-types.cpp
new file mode 100644
index 0000000000000..527fa8c5b79e9
--- /dev/null
+++ b/clang/test/CodeGen/overflow-behavior-types.cpp
@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %s -foverflow-behavior-types \
+// RUN: -fsanitize=signed-integer-overflow,unsigned-integer-overflow,implicit-signed-integer-truncation,implicit-unsigned-integer-truncation \
+// RUN: -emit-llvm -o - | FileCheck %s --check-prefix=DEFAULT
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+class Foo {
+public:
+ unsigned long other;
+ char __wrap a;
+
+ Foo() = delete;
+ Foo(char _a) : a(_a) {}
+
+ decltype(a) getA() const { return a; }
+};
+
+// DEFAULT-LABEL: define {{.*}} @_Z12test_membersc
+void test_members(char some) {
+ Foo foo{some};
+
+ // DEFAULT: %[[A:.*]] = getelementptr inbounds nuw %class.Foo, ptr %foo, i32 0, i32 1
+ // DEFAULT-NEXT: %[[T1:.*]] = load i8, ptr %[[A]], align 8
+ // DEFAULT-NEXT: %inc{{\d*}} = add i8 %[[T1]], 1
+ (++foo.a);
+
+ // DEFAULT: %[[CALL:.*]] = call noundef i8 @_ZNK3Foo4getAEv
+ // DEFAULT-NEXT: add i8 %[[CALL]], 1
+ (void)(foo.getA() + 1);
+}
+
+// DEFAULT-LABEL: define {{.*}} @_Z9test_autoU11ObtWrap_c
+void test_auto(char __wrap a) {
+ auto b = a;
+
+ // DEFAULT: %[[T1:.*]] = load i8, ptr %b
+ // DEFAULT-NEXT: sub i8 %[[T1]], 1
+ (b - 1); // no instrumentation
+}
+
+
+int overloadme(__no_wrap int a) { return 0; }
+int overloadme(int a) { return 1; } // make sure we pick this one
+// DEFAULT-LABEL: define {{.*}}test_overload_set_exact_match
+int test_overload_set_exact_match(int a) {
+ // DEFAULT: call {{.*}} @_Z10overloadmei
+ return overloadme(a);
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 37ff33e5a1523..c325e56726b72 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -166,6 +166,7 @@
// CHECK-NEXT: OpenCLIntelReqdSubGroupSize (SubjectMatchRule_function)
// CHECK-NEXT: OpenCLNoSVM (SubjectMatchRule_variable)
// CHECK-NEXT: OptimizeNone (SubjectMatchRule_function, SubjectMatchRule_objc_method)
+// CHECK-NEXT: OverflowBehavior (SubjectMatchRule_variable, SubjectMatchRule_type_alias, SubjectMatchRule_field)
// CHECK-NEXT: Overloadable (SubjectMatchRule_function)
// CHECK-NEXT: Owner (SubjectMatchRule_record_not_is_union)
// CHECK-NEXT: ParamTypestate (SubjectMatchRule_variable_is_parameter)
diff --git a/clang/test/Sema/attr-overflow-behavior-constexpr.cpp b/clang/test/Sema/attr-overflow-behavior-constexpr.cpp
new file mode 100644
index 0000000000000..171c620712c99
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior-constexpr.cpp
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %s -foverflow-behavior-types -verify -fsyntax-only -std=c++14
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __nowrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap wrap_int;
+typedef int __nowrap nowrap_int;
+
+constexpr wrap_int add(wrap_int a, wrap_int b) {
+ return a + b;
+}
+
+constexpr nowrap_int sub(nowrap_int a, nowrap_int b) {
+ return a - b; // expected-note {{-2147483649 is outside the range of representable values}}
+}
+
+void constexpr_test() {
+ constexpr wrap_int max = 2147483647;
+ constexpr wrap_int one = 1;
+ static_assert(add(max, one) == -2147483648, "constexpr wrapping failed");
+
+ constexpr nowrap_int min = -2147483648;
+ constexpr nowrap_int one_nw = 1;
+ constexpr nowrap_int res = sub(min, one_nw); // expected-error {{constexpr variable 'res' must be initialized by a constant expression}} expected-note {{in call to 'sub(-2147483648, 1)'}}
+}
+
+template <typename T>
+void check_deduction_wrap(T) {
+ static_assert(__is_same(T, wrap_int), "T should be deduced as wrap_int");
+}
+
+template <typename T>
+void check_deduction_nowrap(T) {
+ static_assert(__is_same(T, nowrap_int), "T should be deduced as nowrap_int");
+}
+
+void template_deduction_test() {
+ wrap_int w = 0;
+ check_deduction_wrap(w);
+
+ nowrap_int nw = 0;
+ check_deduction_nowrap(nw);
+}
diff --git a/clang/test/Sema/attr-overflow-behavior-format-strings.c b/clang/test/Sema/attr-overflow-behavior-format-strings.c
new file mode 100644
index 0000000000000..40ef80e3fad47
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior-format-strings.c
@@ -0,0 +1,93 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wformat -foverflow-behavior-types -isystem %S/Inputs %s
+
+// Test format string checking with overflow behavior types
+// This ensures that OverflowBehaviorTypes work seamlessly with printf/scanf
+// without spurious format warnings.
+
+int printf(const char *restrict, ...);
+int sprintf(char *restrict, const char *restrict, ...);
+int snprintf(char *restrict, __SIZE_TYPE__, const char *restrict, ...);
+
+int scanf(const char *restrict, ...);
+int sscanf(const char *restrict, const char *restrict, ...);
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+typedef int __wrap wrap_int;
+typedef int __no_wrap nowrap_int;
+typedef unsigned int __wrap wrap_uint;
+typedef unsigned int __no_wrap nowrap_uint;
+typedef short __wrap wrap_short;
+typedef long __no_wrap nowrap_long;
+
+void test_printf_compatibility() {
+ wrap_int wi = 42;
+ nowrap_int ni = 42;
+ wrap_uint wu = 42U;
+ nowrap_uint nu = 42U;
+ wrap_short ws = 42;
+ nowrap_long nl = 42L;
+
+ // These should all work without warnings - OBTs should be treated as their underlying types
+ printf("%d", wi);
+ printf("%d", ni);
+ printf("%u", wu);
+ printf("%u", nu);
+ printf("%hd", ws);
+ printf("%ld", nl);
+ printf("%x", wu);
+ printf("%o", nu);
+
+ printf("%s", wi); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
+ printf("%f", wi); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
+ printf("%ld", wi); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
+}
+
+void test_scanf_compatibility() {
+ wrap_int wi;
+ nowrap_int ni;
+ wrap_uint wu;
+ nowrap_uint nu;
+ wrap_short ws;
+ nowrap_long nl;
+
+ // These should all work without warnings - pointers to OBTs should be treated as pointers to underlying types
+ scanf("%d", &wi);
+ scanf("%d", &ni);
+ scanf("%u", &wu);
+ scanf("%u", &nu);
+ scanf("%hd", &ws);
+ scanf("%ld", &nl);
+ scanf("%x", &wu);
+ scanf("%o", &nu);
+
+ scanf("%s", &wi); // expected-warning{{format specifies type 'char *' but the argument has type 'wrap_int *'}}
+ scanf("%f", &wi); // expected-warning{{format specifies type 'float *' but the argument has type 'wrap_int *'}}
+ scanf("%ld", &wi); // expected-warning{{format specifies type 'long *' but the argument has type 'wrap_int *'}}
+}
+
+void test_mixed_formats() {
+ wrap_int wi = 42;
+ int regular_int = 42;
+
+ printf("%d + %d = %d", wi, regular_int, wi + regular_int);
+ scanf("%d %d", &wi, ®ular_int);
+}
+
+typedef unsigned char __wrap wrap_byte;
+typedef long long __no_wrap safe_longlong;
+
+void test_typedef_formats() {
+ wrap_byte wb = 255;
+ safe_longlong sll = 123456789LL;
+
+ printf("%hhu", wb); // OK: wrap_byte -> unsigned char for %hhu
+ printf("%lld", sll); // OK: safe_longlong -> long long for %lld
+
+ scanf("%hhu", &wb); // OK: &wb treated as unsigned char* for %hhu
+ scanf("%lld", &sll); // OK: &sll treated as long long* for %lld
+
+ printf("%d", wb); // expected-warning{{format specifies type 'int' but the argument has type 'unsigned char'}}
+ printf("%d", sll); // expected-warning{{format specifies type 'int' but the argument has type 'long long'}}
+}
diff --git a/clang/test/Sema/attr-overflow-behavior-off.c b/clang/test/Sema/attr-overflow-behavior-off.c
new file mode 100644
index 0000000000000..2aac2a887e060
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior-off.c
@@ -0,0 +1,3 @@
+// RUN: %clang_cc1 %s -Winteger-overflow -Wno-unused-value -verify -fsyntax-only
+
+typedef int __attribute__((overflow_behavior(wrap))) wrap_int; // expected-warning {{'overflow_behavior' attribute is ignored because it is not enabled;}}
diff --git a/clang/test/Sema/attr-overflow-behavior-templates.cpp b/clang/test/Sema/attr-overflow-behavior-templates.cpp
new file mode 100644
index 0000000000000..de1e5cad06b2a
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior-templates.cpp
@@ -0,0 +1,72 @@
+// RUN: %clang_cc1 %s -foverflow-behavior-types -verify -fsyntax-only
+// expected-no-diagnostics
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+template<typename T>
+constexpr int template_overload_test(T) {
+ return 10;
+}
+
+constexpr int template_overload_test(int) {
+ return 20;
+}
+
+constexpr int template_overload_test(__wrap int) {
+ return 30;
+}
+
+constexpr int template_overload_test(__no_wrap int) {
+ return 40;
+}
+
+void test_template_overload_resolution() {
+ static_assert(template_overload_test(42) == 20, "int should pick int overload");
+ static_assert(template_overload_test((__wrap int)42) == 30, "__wrap int should pick __wrap int overload");
+ static_assert(template_overload_test((__no_wrap int)42) == 40, "__no_wrap int should pick __no_wrap int overload");
+}
+
+template<typename T>
+struct MultiSpecTester {
+ static constexpr int value = 0;
+};
+
+template<>
+struct MultiSpecTester<int> {
+ static constexpr int value = 1;
+};
+
+void test_choosing_generic_when_only_underlying_present() {
+ static_assert(MultiSpecTester<int>::value == 1, "int should match int specialization");
+ // OBTs don't choose template specialization based on underlying type, they should go with the generic
+ static_assert(MultiSpecTester<__wrap int>::value == 0, "__wrap int should match generic when there isn't a __wrap specialization");
+ static_assert(MultiSpecTester<__no_wrap int>::value == 0, "__no_wrap int should match generic when there isn't a __no_wrap specialization");
+}
+
+template<typename T = int>
+constexpr int only_int_template(int value) {
+ return value + 100;
+}
+
+void test_template_conversion_fallback() {
+ static_assert(only_int_template<int>(42) == 142, "int direct match should work");
+ static_assert(only_int_template<int>((__wrap int)42) == 142, "__wrap int implicit conversion should work");
+ static_assert(only_int_template<int>((__no_wrap int)42) == 142, "__no_wrap int implicit conversion should work");
+}
+
+void simple_overload_test(int);
+void simple_overload_test(__wrap int);
+
+template<typename T>
+void simple_overload_test(T) {}
+
+void test_function_vs_template_overload() {
+ int regular = 42;
+ __wrap int wrapped = 42;
+ __no_wrap int no_wrap = 42;
+
+ simple_overload_test(regular);
+ simple_overload_test(wrapped);
+ simple_overload_test(no_wrap);
+}
diff --git a/clang/test/Sema/attr-overflow-behavior.c b/clang/test/Sema/attr-overflow-behavior.c
new file mode 100644
index 0000000000000..ae78207f5b389
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior.c
@@ -0,0 +1,196 @@
+// RUN: %clang_cc1 %s -Winteger-overflow -Wno-unused-value -foverflow-behavior-types -Woverflow-behavior-conversion -Wconstant-conversion -verify -fsyntax-only -std=c11
+
+typedef int __attribute__((overflow_behavior)) bad_arg_count; // expected-error {{'overflow_behavior' attribute takes one argument}}
+typedef int __attribute__((overflow_behavior(not_real))) bad_arg_spec; // expected-error {{'not_real' is not a valid argument to attribute 'overflow_behavior'}}
+typedef int __attribute__((overflow_behavior("not_real"))) bad_arg_spec_str; // expected-error {{'not_real' is not a valid argument to attribute 'overflow_behavior'}}
+typedef char* __attribute__((overflow_behavior("wrap"))) bad_type; // expected-warning {{'overflow_behavior' attribute cannot be applied to non-integer type 'char *'; attribute ignored}}
+
+typedef int __attribute__((overflow_behavior(wrap))) ok_wrap; // OK
+typedef long __attribute__((overflow_behavior(no_wrap))) ok_nowrap; // OK
+typedef unsigned long __attribute__((overflow_behavior("wrap"))) str_ok_wrap; // OK
+typedef char __attribute__((overflow_behavior("no_wrap"))) str_ok_nowrap; // OK
+
+void foo() {
+ (2147483647 + 100); // expected-warning {{overflow in expression; result is }}
+ (ok_wrap)2147483647 + 100; // no warn
+}
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+void ptr(int a) {
+ int __no_wrap *p = &a; // expected-warning {{initializing '__no_wrap int *' with an expression of type 'int *' discards overflow behavior}}
+}
+
+void ptr2(__no_wrap int a) {
+ int *p = &a; // expected-warning {{initializing 'int *' with an expression of type '__no_wrap int *' discards overflow behavior}}
+}
+
+
+// verify semantics of -Wimplicitly-discarded-overflow-behavior{,-pedantic}
+void imp_disc_pedantic(unsigned a) {}
+void imp_disc(int a) {}
+void imp_disc_test(unsigned __attribute__((overflow_behavior(wrap))) a) {
+ imp_disc_pedantic(a); // expected-warning {{implicit conversion from '__wrap unsigned int' to 'unsigned int' discards overflow behavior}}
+ imp_disc(a); // expected-warning {{implicit conversion from '__wrap unsigned int' to 'int' discards overflow behavior}}
+}
+
+// -Wconversion for assignments that discard overflow behavior
+void assignment_disc(unsigned __attribute__((overflow_behavior(wrap))) a) {
+ int b = a; // expected-warning {{implicit conversion from '__wrap unsigned int' to 'int' during assignment discards overflow behavior}}
+ int c = (int)a; // OK
+}
+
+void constant_conversion() {
+ // expected-warning at +2 {{implicit conversion from '__wrap int' to 'short' changes value from 100000 to -31072}}
+ // expected-warning at +1 {{implicit conversion from '__wrap int' to 'short' during assignment discards overflow behavior}}
+ short x1 = (int __wrap)100000;
+ short __wrap x2 = (int)100000; // No warning expected
+ // expected-warning at +1 {{implicit conversion from 'int' to '__no_wrap short' changes value from 100000 to -31072}}
+ short __no_wrap x3 = (int)100000;
+ // expected-warning at +2 {{implicit conversion from '__no_wrap int' to 'short' changes value from 100000 to -31072}}
+ // expected-warning at +1 {{implicit conversion from '__no_wrap int' to 'short' during assignment discards overflow behavior}}
+ short x4 = (int __no_wrap)100000;
+
+ unsigned short __wrap ux1 = (unsigned int)100000; // No warning - wrapping expected
+ // expected-warning at +2 {{implicit conversion from '__wrap unsigned int' to 'unsigned short' changes value from 100000 to 34464}}
+ // expected-warning at +1 {{implicit conversion from '__wrap unsigned int' to 'unsigned short' discards overflow behavior}}
+ unsigned short ux2 = (unsigned int __wrap)100000;
+ unsigned short __no_wrap ux3 = (unsigned int)100000; // expected-warning {{implicit conversion from 'unsigned int' to '__no_wrap unsigned short' changes value from 100000 to 34464}}
+ unsigned short __no_wrap ux4 = (unsigned int __no_wrap)100000; // expected-warning {{implicit conversion from '__no_wrap unsigned int' to '__no_wrap unsigned short' changes value from 100000 to 34464}}
+ unsigned short __no_wrap ux5 = (unsigned int __wrap)100000; // expected-warning {{implicit conversion from '__wrap unsigned int' to '__no_wrap unsigned short' changes value from 100000 to 34464}}
+}
+
+typedef long s64_typedef1;
+typedef s64_typedef1 __attribute__((overflow_behavior(no_wrap))) nw_s64_typedef2;
+nw_s64_typedef2 global_var;
+void test_nested_typedef_control_flow() {
+ // We had a crash during Sema with nested typedefs and control flow, make
+ // sure we don't crash and just warn.
+ if (global_var) {} // expected-warning {{implicit conversion from 'nw_s64_typedef2'}}
+}
+
+int test_discard_on_return(unsigned long __no_wrap a) {
+ return a; // expected-warning {{implicit conversion from '__no_wrap unsigned long' to 'int' discards overflow behavior}}
+}
+
+// Test OBT pointer compatibility
+void test_obt_pointer_compatibility() {
+ unsigned long x = 42;
+ unsigned long __no_wrap y = 42;
+ unsigned long __wrap z = 42;
+
+ unsigned long *px = &x;
+ unsigned long __no_wrap *py = &y;
+ unsigned long __wrap *pz = &z;
+
+ // Same types - should not warn
+ px = &x; // OK
+ py = &y; // OK
+ pz = &z; // OK
+
+ // Different OBT annotations - should warn but allow
+ // expected-warning at +1 {{assigning to 'unsigned long *' from '__no_wrap unsigned long *' discards overflow behavior}}
+ px = py;
+ // expected-warning at +1 {{assigning to 'unsigned long *' from '__wrap unsigned long *' discards overflow behavior}}
+ px = pz;
+ // expected-warning at +1 {{assigning to '__no_wrap unsigned long *' from 'unsigned long *' discards overflow behavior}}
+ py = px;
+ // expected-warning at +1 {{assigning to '__wrap unsigned long *' from 'unsigned long *' discards overflow behavior}}
+ pz = px;
+ // expected-warning at +1 {{assigning to '__no_wrap unsigned long *' from '__wrap unsigned long *' discards overflow behavior}}
+ py = pz;
+ // expected-warning at +1 {{assigning to '__wrap unsigned long *' from '__no_wrap unsigned long *' discards overflow behavior}}
+ pz = py;
+}
+
+// Test function parameter passing
+// expected-note at +2 {{passing argument to parameter 'p' here}}
+// expected-note at +1 {{passing argument to parameter 'p' here}}
+void func_takes_regular_ptr(unsigned long *p) {}
+// expected-note at +1 {{passing argument to parameter 'p' here}}
+void func_takes_no_wrap_ptr(unsigned long __no_wrap *p) {}
+ // expected-note at +1 {{passing argument to parameter 'p' here}}
+void func_takes_wrap_ptr(unsigned long __wrap *p) {}
+
+void test_function_parameters() {
+ unsigned long x = 42;
+ unsigned long __no_wrap y = 42;
+ unsigned long __wrap z = 42;
+
+ unsigned long *px = &x;
+ unsigned long __no_wrap *py = &y;
+ unsigned long __wrap *pz = &z;
+
+ // Same types - should not warn
+ func_takes_regular_ptr(px); // OK
+ func_takes_no_wrap_ptr(py); // OK
+ func_takes_wrap_ptr(pz); // OK
+
+ // Different OBT annotations - should warn but allow
+ // expected-warning at +1 {{passing '__no_wrap unsigned long *' to parameter of type 'unsigned long *' discards overflow behavior}}
+ func_takes_regular_ptr(py);
+ // expected-warning at +1 {{passing '__wrap unsigned long *' to parameter of type 'unsigned long *' discards overflow behavior}}
+ func_takes_regular_ptr(pz);
+ // expected-warning at +1 {{passing 'unsigned long *' to parameter of type '__no_wrap unsigned long *' discards overflow behavior}}
+ func_takes_no_wrap_ptr(px);
+ // expected-warning at +1 {{passing 'unsigned long *' to parameter of type '__wrap unsigned long *' discards overflow behavior}}
+ func_takes_wrap_ptr(px);
+}
+
+void test_different_underlying_types_for_pointers() {
+ int x = 42;
+ unsigned long __no_wrap y = 42;
+
+ int *px = &x;
+ unsigned long __no_wrap *py = &y;
+
+ px = py; // expected-warning {{incompatible pointer types assigning to 'int *' from '__no_wrap unsigned long *'}}
+}
+
+// expected-warning at +1 {{conflicting 'overflow_behavior' attributes on the same type; 'no_wrap' takes precedence over 'wrap'}}
+typedef int __attribute__((overflow_behavior(wrap))) __attribute__((overflow_behavior(no_wrap))) conflicting_no_wrap_wins;
+// expected-warning at +1 {{conflicting 'overflow_behavior' attributes on the same type; 'no_wrap' takes precedence over 'wrap'}}
+typedef int __attribute__((overflow_behavior(no_wrap))) __attribute__((overflow_behavior(wrap))) conflicting_wrap_ignored;
+
+void test_conflicting_behavior_kinds() {
+ conflicting_no_wrap_wins x = 42;
+ conflicting_wrap_ignored y = 42;
+
+ int __no_wrap *px = &x;
+ int __no_wrap *py = &y;
+}
+
+typedef int __attribute__((overflow_behavior(wrap))) __attribute__((overflow_behavior(wrap))) duplicate_wrap; // no warn
+typedef int __attribute__((overflow_behavior(no_wrap))) __attribute__((overflow_behavior(no_wrap))) duplicate_no_wrap; // no warn
+
+// Test type merging behavior for OBTs on top of typedefs
+typedef int pid_t;
+typedef int clockid_t;
+
+void test_obt_type_merging() {
+ pid_t __wrap a = 1;
+ clockid_t __wrap b = 2;
+ pid_t __wrap c = 4;
+ _Static_assert(_Generic((a + b), int __wrap: 1, default: 0), "a + b should be __wrap int");
+ _Static_assert(_Generic((a + c), pid_t __wrap: 1, default: 0), "a + c should be __wrap pid_t");
+}
+
+typedef unsigned long __no_wrap test_size_t;
+typedef int __wrap test_wrap_int;
+
+void test_pointer_arithmetic_crash_fix() {
+ int a = 42;
+ test_size_t offset = 10;
+ test_wrap_int w_offset = 5;
+
+ int *ptr1 = &a + offset;
+ int *ptr2 = &a + w_offset;
+ int *ptr3 = offset + &a;
+
+ test_size_t bad1 = &a + offset; // expected-error {{incompatible pointer to integer conversion}}
+ test_wrap_int bad2 = &a + w_offset; // expected-error {{incompatible pointer to integer conversion}}
+ test_size_t b = &a + b; // expected-error {{incompatible pointer to integer conversion}}
+ int arr[10];
+ test_size_t diff = &arr[5] - &arr[0]; // OK: pointer difference assigned to OBT
+}
diff --git a/clang/test/Sema/attr-overflow-behavior.cpp b/clang/test/Sema/attr-overflow-behavior.cpp
new file mode 100644
index 0000000000000..2c834d88a0669
--- /dev/null
+++ b/clang/test/Sema/attr-overflow-behavior.cpp
@@ -0,0 +1,145 @@
+// RUN: %clang_cc1 %s -Winteger-overflow -Wno-unused-value -foverflow-behavior-types -Wconstant-conversion -verify -fsyntax-only
+
+typedef int __attribute__((overflow_behavior)) bad_arg_count; // expected-error {{'overflow_behavior' attribute takes one argument}}
+typedef int __attribute__((overflow_behavior(not_real))) bad_arg_spec; // expected-error {{'not_real' is not a valid argument to attribute 'overflow_behavior'}}
+typedef int __attribute__((overflow_behavior("not_real"))) bad_arg_spec_str; // expected-error {{'not_real' is not a valid argument to attribute 'overflow_behavior'}}
+typedef char* __attribute__((overflow_behavior("wrap"))) bad_type; // expected-warning {{'overflow_behavior' attribute cannot be applied to non-integer type 'char *'; attribute ignored}}
+
+typedef int __attribute__((overflow_behavior(wrap))) ok_wrap; // OK
+typedef long __attribute__((overflow_behavior(no_wrap))) ok_nowrap; // OK
+typedef unsigned long __attribute__((overflow_behavior("wrap"))) str_ok_wrap; // OK
+typedef char __attribute__((overflow_behavior("no_wrap"))) str_ok_nowrap; // OK
+
+#define __wrap __attribute__((overflow_behavior(wrap)))
+#define __no_wrap __attribute__((overflow_behavior(no_wrap)))
+
+struct struct_not_allowed {
+ int i;
+} __attribute__((overflow_behavior(wrap))); // expected-warning {{'overflow_behavior' attribute only applies to variables, typedefs, and non-static data members}}
+
+void foo() {
+ (2147483647 + 100); // expected-warning {{overflow in expression; result is }}
+ (ok_wrap)2147483647 + 100; // no warn
+}
+
+// C++ stuff expects no warns
+typedef int __attribute__((overflow_behavior(wrap))) wrap_int;
+
+template <typename T>
+T bar(T a) {
+ return 1UL;
+}
+
+void f() {
+ wrap_int a = 4;
+ bar(a);
+}
+
+class TestOverload {
+ public:
+ void operator<<(int other); // expected-note {{candidate function}}
+ void operator<<(char other); // expected-note {{candidate function}}
+};
+
+void test_overload1() {
+ wrap_int a = 4;
+ TestOverload TO;
+ TO << a; // expected-error {{use of overloaded operator '<<' is ambiguous}}
+}
+
+// expected-note at +1 {{candidate function}}
+int add_one(long a) { // expected-note {{candidate function}}
+ return (a + 1);
+}
+
+// expected-note at +1 {{candidate function}}
+int add_one(char a) { // expected-note {{candidate function}}
+ return (a + 1);
+}
+
+// expected-note at +1 {{candidate function}}
+int add_one(int a) { // expected-note {{candidate function}}
+ return (a + 1);
+}
+
+void test_overload2(wrap_int a) {
+ // to be clear, this is the same ambiguity expected when using a non-OBT int type.
+ add_one(a); // expected-error {{call to 'add_one' is ambiguous}}
+ long __attribute__((overflow_behavior(no_wrap))) b; // don't consider underlying type an exact match.
+ add_one(b); // expected-error {{call to 'add_one' is ambiguous}}
+}
+
+void func(__no_wrap int i);
+void func(int i); // Overload, not invalid redeclaration
+
+template <typename Ty>
+void func2(__no_wrap Ty i) {} // expected-warning {{'overflow_behavior' attribute cannot be applied to non-integer type 'Ty'; attribute ignored}}
+
+template <typename Ty>
+struct S {};
+
+template <>
+struct S<__no_wrap int> {};
+
+template <>
+struct S<int> {};
+
+void ptr(int a) {
+ int __no_wrap *p = &a; // expected-error-re {{cannot initialize a variable of type '__no_wrap int *' {{.*}}with an rvalue of type 'int *'}}
+}
+
+void ptr2(__no_wrap int a) {
+ int *p = &a; // expected-error-re {{cannot initialize a variable of type 'int *' {{.*}}with an rvalue of type '__no_wrap int *'}}
+}
+
+void overloadme(__no_wrap int a); // expected-note {{candidate function}}
+void overloadme(short a); // expected-note {{candidate function}}
+
+void test_overload_ambiguity() {
+ int a;
+ overloadme(a); // expected-error {{call to 'overloadme' is ambiguous}}
+}
+
+void f(void) __attribute__((overflow_behavior(wrap))); // expected-warning {{'overflow_behavior' attribute cannot be applied to non-integer type 'void (void)'; attribute ignored}}
+
+typedef float __attribute__((overflow_behavior(wrap))) wrap_float; // expected-warning {{'overflow_behavior' attribute cannot be applied to non-integer type 'float'; attribute ignored}}
+
+void pointer_compatibility(int* i_ptr) {
+ __no_wrap int* nowrap_ptr;
+
+ // static_cast should fail.
+ nowrap_ptr = static_cast<__no_wrap int*>(i_ptr); // expected-error {{static_cast from 'int *' to '__no_wrap int *' is not allowed}}
+
+ // reinterpret_cast should succeed.
+ nowrap_ptr = reinterpret_cast<__no_wrap int*>(i_ptr);
+ (void)nowrap_ptr;
+}
+
+void cpp_constexpr_bracket_initialization() {
+ constexpr short cx1 = {(int __wrap)100000}; // expected-error {{constant expression evaluates to 100000 which cannot be narrowed to type 'short'}}
+ // expected-warning at -1 {{implicit conversion from '__wrap int' to 'const short' changes value from 100000 to -31072}}
+ // expected-note at -2 {{insert an explicit cast to silence this issue}}
+
+ constexpr short __wrap cx2 = {(int)100000}; // OK - wrapping destination
+
+ constexpr short __no_wrap cx3 = {(int)100000}; // expected-error {{constant expression evaluates to 100000 which cannot be narrowed to type '__no_wrap short'}}
+ // expected-warning at -1 {{implicit conversion from 'int' to '__no_wrap short const' changes value from 100000 to -31072}}
+
+ constexpr short cx4 = {(int __no_wrap)100000}; // expected-error {{constant expression evaluates to 100000 which cannot be narrowed to type 'short'}}
+ // expected-warning at -1 {{implicit conversion from '__no_wrap int' to 'const short' changes value from 100000 to -31072}}
+ // expected-note at -2 {{insert an explicit cast to silence this issue}}
+}
+
+// ensure that all qualifier placements result in the same canonical type
+void test_qualifier_placements() {
+ using ConstInt = const int;
+ using WrapConstInt1 = ConstInt __attribute__((overflow_behavior(wrap)));
+ using WrapConstInt2 = const int __attribute__((overflow_behavior(wrap)));
+ typedef const int __wrap const_int_wrap;
+ typedef int __wrap const int_wrap_const;
+ typedef int __no_wrap const int_no_wrap_const;
+
+ static_assert(__is_same(WrapConstInt1, WrapConstInt2));
+ static_assert(__is_same(const_int_wrap, int_wrap_const));
+ static_assert(!__is_same(const_int_wrap, int_no_wrap_const));
+}
diff --git a/clang/test/SemaCXX/sugar-common-types.cpp b/clang/test/SemaCXX/sugar-common-types.cpp
index dd5fc4a654795..7fc7a29ccc9e2 100644
--- a/clang/test/SemaCXX/sugar-common-types.cpp
+++ b/clang/test/SemaCXX/sugar-common-types.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++20 -x objective-c++ -fobjc-arc -fenable-matrix -triple i686-pc-win32
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++20 -x objective-c++ -fobjc-arc -fenable-matrix -foverflow-behavior-types -triple i686-pc-win32
enum class N {};
@@ -188,6 +188,45 @@ namespace arrays {
} // namespace balanced_qualifiers
} // namespace arrays
+namespace overflow_behavior_types {
+ namespace same_canonical {
+ using WrapB1 = B1 __attribute__((overflow_behavior(wrap)));
+ using WrapB1_2 = B1 __attribute__((overflow_behavior(wrap)));
+ WrapB1 a = 0;
+ WrapB1_2 b = 0;
+ N ta = a;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'WrapB1' (aka '__wrap B1')}}
+ N tb = b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'WrapB1_2' (aka '__wrap B1')}}
+ N tc = 0 ? a : b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type '__wrap B1'}}
+ } // namespace same_canonical
+ namespace same_underlying {
+ using WrapX1 = X1 __attribute__((overflow_behavior(wrap)));
+ using WrapY1 = Y1 __attribute__((overflow_behavior(wrap)));
+ WrapX1 a = 0;
+ WrapY1 b = 0;
+ N ta = a;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'WrapX1' (aka '__wrap X1')}}
+ N tb = b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'WrapY1' (aka '__wrap Y1')}}
+ N tc = 0 ? a : b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type '__wrap B1'}}
+ } // namespace same_underlying
+ namespace balanced_qualifiers {
+ using ConstWrapX1 = const volatile X1 __attribute__((overflow_behavior(wrap)));
+ using WrapY1 = volatile Y1 __attribute__((overflow_behavior(wrap)));
+ volatile ConstWrapX1 a = 0;
+ const volatile WrapY1 b = 0;
+ N ta = a;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'volatile ConstWrapX1' (aka '__wrap X1 const volatile')}}
+ N tb = b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type 'const volatile WrapY1' (aka '__wrap Y1 const volatile')}}
+ N tc = 0 ? a : b;
+ // expected-error at -1 {{cannot initialize a variable of type 'N' with an lvalue of type '__wrap B1 const volatile'}}
+ } // namespace balanced_qualifiers
+} // namespace overflow_behavior_types
+
namespace member_pointers {
template <class T> struct W {
X1 a;
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index 0ed029c39885f..d8982d2a7d708 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -1747,6 +1747,10 @@ bool CursorVisitor::VisitBTFTagAttributedTypeLoc(BTFTagAttributedTypeLoc TL) {
return Visit(TL.getWrappedLoc());
}
+bool CursorVisitor::VisitOverflowBehaviorTypeLoc(OverflowBehaviorTypeLoc TL) {
+ return Visit(TL.getWrappedLoc());
+}
+
bool CursorVisitor::VisitHLSLAttributedResourceTypeLoc(
HLSLAttributedResourceTypeLoc TL) {
return Visit(TL.getWrappedLoc());
>From 48bf3b9c3ede73ad6d1986238ca46604db92453f Mon Sep 17 00:00:00 2001
From: Justin Stitt <justinstitt at google.com>
Date: Tue, 9 Sep 2025 10:28:57 -0700
Subject: [PATCH 2/2] add OverflowBehaviorType to lldb switches
Signed-off-by: Justin Stitt <justinstitt at google.com>
---
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp | 3 +++
1 file changed, 3 insertions(+)
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 39aacdb58e694..23e7f5020b4d2 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -4184,6 +4184,7 @@ TypeSystemClang::GetTypeClass(lldb::opaque_compiler_type_t type) {
// Ext-Int is just an integer type.
case clang::Type::BitInt:
case clang::Type::DependentBitInt:
+ case clang::Type::OverflowBehavior:
return lldb::eTypeClassBuiltin;
case clang::Type::ObjCObjectPointer:
return lldb::eTypeClassObjCObjectPointer;
@@ -4887,6 +4888,7 @@ lldb::Encoding TypeSystemClang::GetEncoding(lldb::opaque_compiler_type_t type,
case clang::Type::BitInt:
case clang::Type::DependentBitInt:
+ case clang::Type::OverflowBehavior:
return qual_type->isUnsignedIntegerType() ? lldb::eEncodingUint
: lldb::eEncodingSint;
@@ -5188,6 +5190,7 @@ lldb::Format TypeSystemClang::GetFormat(lldb::opaque_compiler_type_t type) {
case clang::Type::BitInt:
case clang::Type::DependentBitInt:
+ case clang::Type::OverflowBehavior:
return qual_type->isUnsignedIntegerType() ? lldb::eFormatUnsigned
: lldb::eFormatDecimal;
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