[llvm] b0391df - [clang][Codegen] Introduce the disable_sanitizer_instrumentation attribute
Alexander Potapenko via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 20 05:06:13 PDT 2021
Author: Alexander Potapenko
Date: 2021-08-20T14:01:06+02:00
New Revision: b0391dfc737ede147e128fe877045f61fc5e4905
URL: https://github.com/llvm/llvm-project/commit/b0391dfc737ede147e128fe877045f61fc5e4905
DIFF: https://github.com/llvm/llvm-project/commit/b0391dfc737ede147e128fe877045f61fc5e4905.diff
LOG: [clang][Codegen] Introduce the disable_sanitizer_instrumentation attribute
The purpose of __attribute__((disable_sanitizer_instrumentation)) is to
prevent all kinds of sanitizer instrumentation applied to a certain
function, Objective-C method, or global variable.
The no_sanitize(...) attribute drops instrumentation checks, but may
still insert code preventing false positive reports. In some cases
though (e.g. when building Linux kernel with -fsanitize=kernel-memory
or -fsanitize=thread) the users may want to avoid any kind of
instrumentation.
Differential Revision: https://reviews.llvm.org/D108029
Added:
clang/test/CodeGen/attr-disable-sanitizer-instrumentation.c
Modified:
clang/include/clang/Basic/Attr.td
clang/include/clang/Basic/AttrDocs.td
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/CodeGen/CodeGenFunction.h
clang/test/Misc/pragma-attribute-supported-attributes-list.test
llvm/docs/BitCodeFormat.rst
llvm/docs/LangRef.rst
llvm/include/llvm/AsmParser/LLToken.h
llvm/include/llvm/Bitcode/LLVMBitCodes.h
llvm/include/llvm/IR/Attributes.td
llvm/lib/AsmParser/LLLexer.cpp
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
llvm/lib/Transforms/Utils/CodeExtractor.cpp
llvm/test/Bitcode/attributes.ll
llvm/test/Bitcode/compatibility.ll
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 13d8c15001c92..f9ae1b8d86281 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2948,6 +2948,13 @@ def NoSanitizeSpecific : InheritableAttr {
let ASTNode = 0;
}
+def DisableSanitizerInstrumentation : InheritableAttr {
+ let Spellings = [Clang<"disable_sanitizer_instrumentation">];
+ let Subjects = SubjectList<[Function, ObjCMethod, GlobalVar]>;
+ let Documentation = [DisableSanitizerInstrumentationDocs];
+ let SimpleHandler = 1;
+}
+
def CFICanonicalJumpTable : InheritableAttr {
let Spellings = [Clang<"cfi_canonical_jump_table">];
let Subjects = SubjectList<[Function], ErrorDiag>;
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index a1206347ae454..5c63c8440ad80 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -2602,6 +2602,18 @@ full list of supported sanitizer flags.
}];
}
+def DisableSanitizerInstrumentationDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+Use the ``disable_sanitizer_instrumentation`` attribute on a function,
+Objective-C method, or global variable, to specify that no sanitizer
+instrumentation should be applied.
+
+This is not the same as ``__attribute__((no_sanitize(...)))``, which depending
+on the tool may still insert instrumentation to prevent false positive reports.
+ }];
+}
+
def NoSanitizeAddressDocs : Documentation {
let Category = DocCatFunction;
// This function has multiple distinct spellings, and so it requires a custom
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index dca42045325df..e3a66318c086c 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -381,6 +381,9 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
"__cyg_profile_func_exit");
}
+ if (ShouldSkipSanitizerInstrumentation())
+ CurFn->addFnAttr(llvm::Attribute::DisableSanitizerInstrumentation);
+
// Emit debug descriptor for function end.
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitFunctionEnd(Builder, CurFn);
@@ -519,6 +522,12 @@ bool CodeGenFunction::ShouldInstrumentFunction() {
return true;
}
+bool CodeGenFunction::ShouldSkipSanitizerInstrumentation() {
+ if (!CurFuncDecl)
+ return false;
+ return CurFuncDecl->hasAttr<DisableSanitizerInstrumentationAttr>();
+}
+
/// ShouldXRayInstrument - Return true if the current function should be
/// instrumented with XRay nop sleds.
bool CodeGenFunction::ShouldXRayInstrumentFunction() const {
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 0baa45e6b9f27..f74bff91f007c 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -2286,6 +2286,10 @@ class CodeGenFunction : public CodeGenTypeCache {
/// instrumented with __cyg_profile_func_* calls
bool ShouldInstrumentFunction();
+ /// ShouldSkipSanitizerInstrumentation - Return true if the current function
+ /// should not be instrumented with sanitizers.
+ bool ShouldSkipSanitizerInstrumentation();
+
/// ShouldXRayInstrument - Return true if the current function should be
/// instrumented with XRay nop sleds.
bool ShouldXRayInstrumentFunction() const;
diff --git a/clang/test/CodeGen/attr-disable-sanitizer-instrumentation.c b/clang/test/CodeGen/attr-disable-sanitizer-instrumentation.c
new file mode 100644
index 0000000000000..74ebe1b548807
--- /dev/null
+++ b/clang/test/CodeGen/attr-disable-sanitizer-instrumentation.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -debug-info-kind=limited %s -emit-llvm -o - | FileCheck %s
+
+void t1() __attribute__((disable_sanitizer_instrumentation)) {
+}
+// CHECK: disable_sanitizer_instrumentation
+// CHECK-NEXT: void @t1
+
+// CHECK-NOT: disable_sanitizer_instrumentation
+// CHECK: void @t2
+void t2() {
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index bf960ca046821..88488d210945f 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -57,6 +57,7 @@
// CHECK-NEXT: DLLExport (SubjectMatchRule_function, SubjectMatchRule_variable, SubjectMatchRule_record, SubjectMatchRule_objc_interface)
// CHECK-NEXT: DLLImport (SubjectMatchRule_function, SubjectMatchRule_variable, SubjectMatchRule_record, SubjectMatchRule_objc_interface)
// CHECK-NEXT: Destructor (SubjectMatchRule_function)
+// CHECK-NEXT: DisableSanitizerInstrumentation (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_variable_is_global)
// CHECK-NEXT: DisableTailCalls (SubjectMatchRule_function, SubjectMatchRule_objc_method)
// CHECK-NEXT: EnableIf (SubjectMatchRule_function)
// CHECK-NEXT: EnforceTCB (SubjectMatchRule_function)
diff --git a/llvm/docs/BitCodeFormat.rst b/llvm/docs/BitCodeFormat.rst
index fcc10d5efe5b7..32f87fe719f88 100644
--- a/llvm/docs/BitCodeFormat.rst
+++ b/llvm/docs/BitCodeFormat.rst
@@ -1075,6 +1075,8 @@ The integer codes are mapped to well-known attributes as follows.
* code 74: ``vscale_range(<Min>[, <Max>])``
* code 75: ``swiftasync``
* code 76: ``nosanitize_coverage``
+* code 77: ``elementtype``
+* code 78: ``disable_sanitizer_instrumentation``
.. note::
The ``allocsize`` attribute has a special encoding for its arguments. Its two
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index dd7ea4c58b755..543783a8a90d2 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1582,6 +1582,19 @@ example:
can prove that the function does not execute any convergent operations.
Similarly, the optimizer may remove ``convergent`` on calls/invokes when it
can prove that the call/invoke cannot call a convergent function.
+``disable_sanitizer_instrumentation``
+ When instrumenting code with sanitizers, it can be important to skip certain
+ functions to ensure no instrumentation is applied to them.
+
+ This attribute is not always similar to absent ``sanitize_<name>``
+ attributes: depending on the specific sanitizer, code can be inserted into
+ functions regardless of the ``sanitize_<name>`` attribute to prevent false
+ positive reports.
+
+ ``disable_sanitizer_instrumentation`` disables all kinds of instrumentation,
+ taking precedence over the ``sanitize_<name>`` attributes and other compiler
+ flags.
+
``"frame-pointer"``
This attribute tells the code generator whether the function
should keep the frame pointer. The code generator may emit the frame pointer
diff --git a/llvm/include/llvm/AsmParser/LLToken.h b/llvm/include/llvm/AsmParser/LLToken.h
index e38b7fd0f3ea9..bc35f6381c0db 100644
--- a/llvm/include/llvm/AsmParser/LLToken.h
+++ b/llvm/include/llvm/AsmParser/LLToken.h
@@ -190,6 +190,7 @@ enum Kind {
kw_convergent,
kw_dereferenceable,
kw_dereferenceable_or_null,
+ kw_disable_sanitizer_instrumentation,
kw_elementtype,
kw_inaccessiblememonly,
kw_inaccessiblemem_or_argmemonly,
diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index 28870afb2fcb3..04eb2739cbd5a 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -671,6 +671,7 @@ enum AttributeKindCodes {
ATTR_KIND_SWIFT_ASYNC = 75,
ATTR_KIND_NO_SANITIZE_COVERAGE = 76,
ATTR_KIND_ELEMENTTYPE = 77,
+ ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION = 78,
};
enum ComdatSelectionKindCodes {
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 99b474161df7a..de25b51a62927 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -86,6 +86,9 @@ def Dereferenceable : IntAttr<"dereferenceable", [ParamAttr, RetAttr]>;
def DereferenceableOrNull : IntAttr<"dereferenceable_or_null",
[ParamAttr, RetAttr]>;
+/// Do not instrument function with sanitizers.
+def DisableSanitizerInstrumentation: EnumAttr<"disable_sanitizer_instrumentation", [FnAttr]>;
+
/// Provide pointer element type to intrinsic.
def ElementType : TypeAttr<"elementtype", [ParamAttr]>;
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index 4f72c6f9921a9..bee3d947de930 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -643,6 +643,7 @@ lltok::Kind LLLexer::LexIdentifier() {
KEYWORD(convergent);
KEYWORD(dereferenceable);
KEYWORD(dereferenceable_or_null);
+ KEYWORD(disable_sanitizer_instrumentation);
KEYWORD(elementtype);
KEYWORD(inaccessiblememonly);
KEYWORD(inaccessiblemem_or_argmemonly);
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index eb6a7f39b9341..49ba562d8ab7b 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1388,6 +1388,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
return Attribute::Cold;
case bitc::ATTR_KIND_CONVERGENT:
return Attribute::Convergent;
+ case bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION:
+ return Attribute::DisableSanitizerInstrumentation;
case bitc::ATTR_KIND_ELEMENTTYPE:
return Attribute::ElementType;
case bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY:
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index c5d8c553a340a..1d578a9674296 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -626,6 +626,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
return bitc::ATTR_KIND_IN_ALLOCA;
case Attribute::Cold:
return bitc::ATTR_KIND_COLD;
+ case Attribute::DisableSanitizerInstrumentation:
+ return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
case Attribute::Hot:
return bitc::ATTR_KIND_HOT;
case Attribute::ElementType:
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index ccd62b7bbd41e..0411c9bfab5d7 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -943,6 +943,7 @@ Function *CodeExtractor::constructFunction(const ValueSet &inputs,
// Those attributes should be safe to propagate to the extracted function.
case Attribute::AlwaysInline:
case Attribute::Cold:
+ case Attribute::DisableSanitizerInstrumentation:
case Attribute::Hot:
case Attribute::NoRecurse:
case Attribute::InlineHint:
diff --git a/llvm/test/Bitcode/attributes.ll b/llvm/test/Bitcode/attributes.ll
index 6ba8ce2854d6b..4ec827fe63e0c 100644
--- a/llvm/test/Bitcode/attributes.ll
+++ b/llvm/test/Bitcode/attributes.ll
@@ -472,6 +472,12 @@ define void @f79() {
ret void
}
+; CHECK: define void @f80() #50
+define void @f80() disable_sanitizer_instrumentation
+{
+ ret void;
+}
+
; CHECK: attributes #0 = { noreturn }
; CHECK: attributes #1 = { nounwind }
; CHECK: attributes #2 = { readnone }
@@ -522,4 +528,5 @@ define void @f79() {
; CHECK: attributes #47 = { vscale_range(1,0) }
; CHECK: attributes #48 = { nosanitize_coverage }
; CHECK: attributes #49 = { noprofile }
+; CHECK: attributes #50 = { disable_sanitizer_instrumentation }
; CHECK: attributes #[[NOBUILTIN]] = { nobuiltin }
diff --git a/llvm/test/Bitcode/compatibility.ll b/llvm/test/Bitcode/compatibility.ll
index c2bfb3a3523d3..2281938c6d834 100644
--- a/llvm/test/Bitcode/compatibility.ll
+++ b/llvm/test/Bitcode/compatibility.ll
@@ -1510,7 +1510,7 @@ exit:
; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
call void @f.nobuiltin() builtin
- ; CHECK: call void @f.nobuiltin() #45
+ ; CHECK: call void @f.nobuiltin() #46
call fastcc noalias i32* @f.noalias() noinline
; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1907,6 +1907,9 @@ define void @instructions.strictfp() strictfp {
declare void @f.nosanitize_coverage() nosanitize_coverage
; CHECK: declare void @f.nosanitize_coverage() #44
+declare void @f.disable_sanitizer_instrumentation() disable_sanitizer_instrumentation
+; CHECK: declare void @f.disable_sanitizer_instrumentation() #45
+
; immarg attribute
declare void @llvm.test.immarg.intrinsic(i32 immarg)
; CHECK: declare void @llvm.test.immarg.intrinsic(i32 immarg)
@@ -1965,7 +1968,8 @@ declare void @byval_named_type(%named_type* byval(%named_type))
; CHECK: attributes #42 = { speculatable }
; CHECK: attributes #43 = { strictfp }
; CHECK: attributes #44 = { nosanitize_coverage }
-; CHECK: attributes #45 = { builtin }
+; CHECK: attributes #45 = { disable_sanitizer_instrumentation }
+; CHECK: attributes #46 = { builtin }
;; Metadata
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