[clang] [clang] Fix false positive -Wmissing-field-initializer for anonymous unions (PR #70829)
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cfe-commits at lists.llvm.org
Tue Oct 31 10:01:40 PDT 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Mariya Podchishchaeva (Fznamznon)
<details>
<summary>Changes</summary>
Normally warning is not reported when a field has default initializer. Do so for anonymous unions with default initializers as well. No release note since it is a regression in clang 18.
Fixes https://github.com/llvm/llvm-project/issues/70384
---
Full diff: https://github.com/llvm/llvm-project/pull/70829.diff
2 Files Affected:
- (modified) clang/lib/Sema/SemaInit.cpp (+57-42)
- (modified) clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp (+65-1)
``````````diff
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index ec796def96ad3d8..881e67587e430e7 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -349,17 +349,13 @@ class InitListChecker {
bool SubobjectIsDesignatorContext, unsigned &Index,
InitListExpr *StructuredList,
unsigned &StructuredIndex);
- bool CheckDesignatedInitializer(const InitializedEntity &Entity,
- InitListExpr *IList, DesignatedInitExpr *DIE,
- unsigned DesigIdx,
- QualType &CurrentObjectType,
- RecordDecl::field_iterator *NextField,
- llvm::APSInt *NextElementIndex,
- unsigned &Index,
- InitListExpr *StructuredList,
- unsigned &StructuredIndex,
- bool FinishSubobjectInit,
- bool TopLevelObject);
+ bool CheckDesignatedInitializer(
+ const InitializedEntity &Entity, InitListExpr *IList,
+ DesignatedInitExpr *DIE, unsigned DesigIdx, QualType &CurrentObjectType,
+ RecordDecl::field_iterator *NextField, llvm::APSInt *NextElementIndex,
+ unsigned &Index, InitListExpr *StructuredList, unsigned &StructuredIndex,
+ bool FinishSubobjectInit, bool TopLevelObject,
+ llvm::SmallPtrSetImpl<FieldDecl *> *InitializedFields = nullptr);
InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
QualType CurrentObjectType,
InitListExpr *StructuredList,
@@ -2248,7 +2244,8 @@ void InitListChecker::CheckStructUnionTypes(
// the next field that we'll be initializing.
bool DesignatedInitFailed = CheckDesignatedInitializer(
Entity, IList, DIE, 0, DeclType, &Field, nullptr, Index,
- StructuredList, StructuredIndex, true, TopLevelObject);
+ StructuredList, StructuredIndex, true, TopLevelObject,
+ &InitializedFields);
if (DesignatedInitFailed)
hadError = true;
@@ -2256,7 +2253,6 @@ void InitListChecker::CheckStructUnionTypes(
DesignatedInitExpr::Designator *D = DIE->getDesignator(0);
if (!VerifyOnly && D->isFieldDesignator()) {
FieldDecl *F = D->getFieldDecl();
- InitializedFields.insert(F);
if (!DesignatedInitFailed) {
QualType ET = SemaRef.Context.getBaseElementType(F->getType());
if (checkDestructorReference(ET, InitLoc, SemaRef)) {
@@ -2365,21 +2361,43 @@ void InitListChecker::CheckStructUnionTypes(
!RD->isUnion()) {
// It is possible we have one or more unnamed bitfields remaining.
// Find first (if any) named field and emit warning.
- for (RecordDecl::field_iterator it = HasDesignatedInit ? RD->field_begin()
- : Field,
- end = RD->field_end();
- it != end; ++it) {
- if (HasDesignatedInit && InitializedFields.count(*it))
- continue;
+ auto MissingFieldCheck = [&](const RecordDecl *Record,
+ RecordDecl::field_iterator StartField,
+ auto &&MissingFieldCheck) -> bool {
+ FieldDecl *FirstUninitialized = nullptr;
+ for (RecordDecl::field_iterator it = StartField,
+ end = Record->field_end();
+ it != end; ++it) {
+ bool AllSet = false;
+ if (it->isAnonymousStructOrUnion()) {
+ RecordDecl *RDAnon = it->getType()->getAsRecordDecl();
+ AllSet = MissingFieldCheck(RDAnon, RDAnon->field_begin(),
+ MissingFieldCheck);
+ }
+
+ if ((HasDesignatedInit && InitializedFields.count(*it)) ||
+ it->hasInClassInitializer() || AllSet) {
+ if (Record->isUnion())
+ return true;
+ continue;
+ }
- if (!it->isUnnamedBitfield() && !it->hasInClassInitializer() &&
- !it->getType()->isIncompleteArrayType()) {
+ if (!it->isUnnamedBitfield() &&
+ !it->getType()->isIncompleteArrayType() &&
+ !it->isAnonymousStructOrUnion() && !FirstUninitialized)
+ FirstUninitialized = *it;
+ }
+
+ if (FirstUninitialized) {
SemaRef.Diag(IList->getSourceRange().getEnd(),
diag::warn_missing_field_initializers)
- << *it;
- break;
+ << FirstUninitialized;
+ return false;
}
- }
+ return true;
+ };
+ MissingFieldCheck(RD, HasDesignatedInit ? RD->field_begin() : Field,
+ MissingFieldCheck);
}
// Check that any remaining fields can be value-initialized if we're not
@@ -2537,19 +2555,13 @@ class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
/// actually be initialized.
///
/// @returns true if there was an error, false otherwise.
-bool
-InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
- InitListExpr *IList,
- DesignatedInitExpr *DIE,
- unsigned DesigIdx,
- QualType &CurrentObjectType,
- RecordDecl::field_iterator *NextField,
- llvm::APSInt *NextElementIndex,
- unsigned &Index,
- InitListExpr *StructuredList,
- unsigned &StructuredIndex,
- bool FinishSubobjectInit,
- bool TopLevelObject) {
+bool InitListChecker::CheckDesignatedInitializer(
+ const InitializedEntity &Entity, InitListExpr *IList,
+ DesignatedInitExpr *DIE, unsigned DesigIdx, QualType &CurrentObjectType,
+ RecordDecl::field_iterator *NextField, llvm::APSInt *NextElementIndex,
+ unsigned &Index, InitListExpr *StructuredList, unsigned &StructuredIndex,
+ bool FinishSubobjectInit, bool TopLevelObject,
+ llvm::SmallPtrSetImpl<FieldDecl *> *InitializedFields) {
if (DesigIdx == DIE->size()) {
// C++20 designated initialization can result in direct-list-initialization
// of the designated subobject. This is the only way that we can end up
@@ -2853,8 +2865,11 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
// Update the designator with the field declaration.
- if (!VerifyOnly)
+ if (!VerifyOnly) {
D->setFieldDecl(*Field);
+ if (InitializedFields)
+ InitializedFields->insert(*Field);
+ }
// Make sure that our non-designated initializer list has space
// for a subobject corresponding to this field.
@@ -2929,10 +2944,10 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
InitializedEntity MemberEntity =
InitializedEntity::InitializeMember(*Field, &Entity);
- if (CheckDesignatedInitializer(MemberEntity, IList, DIE, DesigIdx + 1,
- FieldType, nullptr, nullptr, Index,
- StructuredList, newStructuredIndex,
- FinishSubobjectInit, false))
+ if (CheckDesignatedInitializer(
+ MemberEntity, IList, DIE, DesigIdx + 1, FieldType, nullptr,
+ nullptr, Index, StructuredList, newStructuredIndex,
+ FinishSubobjectInit, false, InitializedFields))
return true;
}
diff --git a/clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp b/clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp
index 510ace58c35a6aa..87bc01a51d2f297 100644
--- a/clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp
+++ b/clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp
@@ -4,7 +4,7 @@
// RUN: %clang_cc1 -std=c++20 %s -verify=cxx20,expected,reorder -Wno-c99-designator -Werror=reorder-init-list -Wno-initializer-overrides
// RUN: %clang_cc1 -std=c++20 %s -verify=cxx20,expected,override -Wno-c99-designator -Wno-reorder-init-list -Werror=initializer-overrides
// RUN: %clang_cc1 -std=c++20 %s -verify=cxx20,expected -Wno-c99-designator -Wno-reorder-init-list -Wno-initializer-overrides
-// RUN: %clang_cc1 -std=c++20 %s -verify=cxx20,expected,wmissing -Wmissing-field-initializers -Wno-c99-designator -Wno-reorder-init-list -Wno-initializer-overrides
+// RUN: %clang_cc1 -std=c++20 %s -verify=cxx20,expected,wmissing -Wmissing-field-initializers -Wno-c99-designator -Wno-reorder-init-list -Wno-initializer-overrides -D NON_PEDANTIC
namespace class_with_ctor {
@@ -247,3 +247,67 @@ void foo() {
//
}
}
+
+namespace GH70384 {
+
+struct A {
+ int m;
+ union { int a; float n = 0; };
+};
+
+struct B {
+ int m;
+ int b;
+ union { int a ; };
+};
+
+union CU {
+ int a = 1;
+ double b;
+};
+
+struct C {
+ int a;
+ union { int b; CU c;};
+};
+
+struct CC {
+ int a;
+ CU c;
+};
+
+void foo() {
+ A a = A{.m = 0};
+ A aa = {0};
+ A aaa = {.a = 7}; // wmissing-warning {{missing field 'm' initializer}}
+ B b = {.m = 1, .b = 3 }; //wmissing-warning {{missing field 'a' initializer}}
+ B bb = {1}; // wmissing-warning {{missing field 'b' initializer}}
+ // wmissing-warning at -1 {{missing field 'a' initializer}}
+ C c = {.a = 1}; // wmissing-warning {{missing field 'b' initializer}}
+ CC cc = {.a = 1}; //// wmissing-warning {{missing field 'c' initializer}}
+}
+
+#if defined NON_PEDANTIC
+struct C1 {
+ int m;
+ union { float b; union {int n = 1; }; };
+};
+
+struct C2 {
+ int m;
+ struct { float b; int n = 1; };
+};
+
+struct C3 {
+ int m;
+ struct { float b = 1; union {int a;}; int n = 1; };
+};
+
+C1 c = C1{.m = 1};
+C1 cc = C1{.b = 1}; // wmissing-warning {{missing field 'm' initializer}}
+C2 c1 = C2{.m = 1}; // wmissing-warning {{missing field 'b' initializer}}
+C2 c22 = C2{.m = 1, .b = 1};
+C3 c2 = C3{.b = 1}; // wmissing-warning {{missing field 'a' initializer}}
+ // wmissing-warning at -1 {{missing field 'm' initializer}}
+#endif // NON_PEDANTIC
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/70829
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