[llvm-branch-commits] [clang] 8c5c652 - [clang][ExprConstant] Fix crash on uninitialized base class subobject
Tobias Hieta via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Wed Aug 30 08:08:24 PDT 2023
Author: Takuya Shimizu
Date: 2023-08-30T16:59:25+02:00
New Revision: 8c5c652ed71ba3948f52f707d8022eb5ec87d802
URL: https://github.com/llvm/llvm-project/commit/8c5c652ed71ba3948f52f707d8022eb5ec87d802
DIFF: https://github.com/llvm/llvm-project/commit/8c5c652ed71ba3948f52f707d8022eb5ec87d802.diff
LOG: [clang][ExprConstant] Fix crash on uninitialized base class subobject
This patch fixes the reported regression caused by D146358 through adding notes about an uninitialized base class when we diagnose uninitialized constructor.
This also changes the wording from the old one in order to make it clear that the uninitialized subobject is a base class and its constructor is not called.
Wording changes:
BEFORE: `subobject of type 'Base' is not initialized`
AFTER: `constructor of base class 'Base' is not called`
Fixes https://github.com/llvm/llvm-project/issues/63496
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D153969
Added:
clang/test/Misc/constexpr-subobj-init-source-ranges.cpp
clang/test/SemaCXX/constexpr-subobj-initialization.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticASTKinds.td
clang/lib/AST/ExprConstant.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d755626f795d51..3d9774d5c7ff2d 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -472,6 +472,8 @@ Improvements to Clang's diagnostics
- Clang now emits ``-Wconstant-logical-operand`` warning even when constant logical
operand is on left side.
(`#37919 <https://github.com/llvm/llvm-project/issues/37919>`_)
+- Clang contexpr evaluator now displays notes as well as an error when a constructor
+ of a base class is not called in the constructor of its derived class.
Bug Fixes in This Version
-------------------------
diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index 566cdc3406058f..0794ed7ba68373 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -70,6 +70,8 @@ def note_consteval_address_accessible : Note<
"is not a constant expression">;
def note_constexpr_uninitialized : Note<
"subobject %0 is not initialized">;
+def note_constexpr_uninitialized_base : Note<
+ "constructor of base class %0 is not called">;
def note_constexpr_static_local : Note<
"control flows through the definition of a %select{static|thread_local}0 variable">;
def note_constexpr_subobject_declared_here : Note<
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 2f2f4eef852fdc..f1bad0c7f7f227 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2418,9 +2418,16 @@ static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
unsigned BaseIndex = 0;
for (const CXXBaseSpecifier &BS : CD->bases()) {
- if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
- Value.getStructBase(BaseIndex), Kind,
- /*SubobjectDecl=*/nullptr, CheckedTemps))
+ const APValue &BaseValue = Value.getStructBase(BaseIndex);
+ if (!BaseValue.hasValue()) {
+ SourceLocation TypeBeginLoc = BS.getBaseTypeLoc();
+ Info.FFDiag(TypeBeginLoc, diag::note_constexpr_uninitialized_base)
+ << BS.getType() << SourceRange(TypeBeginLoc, BS.getEndLoc());
+ return false;
+ }
+ if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(), BaseValue,
+ Kind, /*SubobjectDecl=*/nullptr,
+ CheckedTemps))
return false;
++BaseIndex;
}
diff --git a/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp b/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp
new file mode 100644
index 00000000000000..342da2d8866687
--- /dev/null
+++ b/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp
@@ -0,0 +1,11 @@
+// RUN: not %clang_cc1 -fsyntax-only -fdiagnostics-print-source-range-info %s 2>&1 | FileCheck %s --strict-whitespace
+
+struct DelBase {
+ constexpr DelBase() = delete;
+};
+
+// CHECK: :{[[@LINE+1]]:21-[[@LINE+1]]:28}
+struct Foo : public DelBase {
+ constexpr Foo() {};
+};
+constexpr Foo f;
diff --git a/clang/test/SemaCXX/constexpr-subobj-initialization.cpp b/clang/test/SemaCXX/constexpr-subobj-initialization.cpp
new file mode 100644
index 00000000000000..cd096a92709378
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-subobj-initialization.cpp
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+namespace baseclass_uninit {
+struct DelBase {
+ constexpr DelBase() = delete; // expected-note {{'DelBase' has been explicitly marked deleted here}}
+};
+
+struct Foo : DelBase { // expected-note 2{{constructor of base class 'DelBase' is not called}}
+ constexpr Foo() {}; // expected-error {{call to deleted constructor of 'DelBase'}}
+};
+constexpr Foo f; // expected-error {{must be initialized by a constant expression}}
+struct Bar : Foo {
+ constexpr Bar() {};
+};
+constexpr Bar bar; // expected-error {{must be initialized by a constant expression}}
+
+struct Base {};
+struct A : Base { // expected-note {{constructor of base class 'Base' is not called}}
+ constexpr A() : value() {} // expected-error {{member initializer 'value' does not name a non-static data member or base class}}
+};
+
+constexpr A a; // expected-error {{must be initialized by a constant expression}}
+
+struct B : Base { // expected-note {{constructor of base class 'Base' is not called}}
+ constexpr B() : {} // expected-error {{expected class member or base class name}}
+};
+
+constexpr B b; // expected-error {{must be initialized by a constant expression}}
+} // namespace baseclass_uninit
+
+
+struct Foo {
+ constexpr Foo(); // expected-note 2{{declared here}}
+};
+
+constexpr Foo ff; // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{undefined constructor 'Foo' cannot be used in a constant expression}}
+
+struct Bar : protected Foo {
+ int i;
+ constexpr Bar() : i(12) {} // expected-note {{undefined constructor 'Foo' cannot be used in a constant expression}}
+};
+
+constexpr Bar bb; // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{in call to 'Bar()'}}
+
+template <typename Ty>
+struct Baz {
+ constexpr Baz(); // expected-note {{declared here}}
+};
+
+struct Quux : Baz<Foo>, private Bar {
+ int i;
+ constexpr Quux() : i(12) {} // expected-note {{undefined constructor 'Baz' cannot be used in a constant expression}}
+};
+
+constexpr Quux qx; // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{in call to 'Quux()'}}
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