[clang] 24c91d4 - [clang][ExprConstant] Fix crash on uninitialized base class subobject
Takuya Shimizu via cfe-commits
cfe-commits at lists.llvm.org
Mon Aug 7 23:56:28 PDT 2023
Author: Takuya Shimizu
Date: 2023-08-08T15:53:17+09:00
New Revision: 24c91d443222bdb20205630d300ae61bfa07067e
URL: https://github.com/llvm/llvm-project/commit/24c91d443222bdb20205630d300ae61bfa07067e
DIFF: https://github.com/llvm/llvm-project/commit/24c91d443222bdb20205630d300ae61bfa07067e.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 44f6ad807daf8f..babade1c70b067 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -121,6 +121,8 @@ Improvements to Clang's diagnostics
-----------------------------------
- Clang constexpr evaluator now prints template arguments when displaying
template-specialization function calls.
+- 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 f73a289f80ca95..d2656310e79c9b 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 361e8efe4cdf33..7d6796dd9d3598 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2450,9 +2450,16 @@ 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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