[Clang] Improve testing for the flexible array member (#89462)
Testing for the name of the flexible array member isn't as robust as
testing the FieldDecl pointers.
GitOrigin-RevId: 712d7dba4f27a1990241e02435d765a5a3808aea
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 7e5f2ed..e67a600 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -822,8 +822,9 @@
return ConstantInt::get(ResType, ObjectSize, /*isSigned=*/true);
}
-const FieldDecl *CodeGenFunction::FindFlexibleArrayMemberField(
- ASTContext &Ctx, const RecordDecl *RD, StringRef Name, uint64_t &Offset) {
+const FieldDecl *CodeGenFunction::FindFlexibleArrayMemberFieldAndOffset(
+ ASTContext &Ctx, const RecordDecl *RD, const FieldDecl *FAMDecl,
+ uint64_t &Offset) {
const LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel =
getLangOpts().getStrictFlexArraysLevel();
uint32_t FieldNo = 0;
@@ -832,7 +833,7 @@
return nullptr;
for (const FieldDecl *FD : RD->fields()) {
- if ((Name.empty() || FD->getNameAsString() == Name) &&
+ if ((!FAMDecl || FD == FAMDecl) &&
Decl::isFlexibleArrayMemberLike(
Ctx, FD, FD->getType(), StrictFlexArraysLevel,
/*IgnoreTemplateOrMacroSubstitution=*/true)) {
@@ -843,8 +844,8 @@
QualType Ty = FD->getType();
if (Ty->isRecordType()) {
- if (const FieldDecl *Field = FindFlexibleArrayMemberField(
- Ctx, Ty->getAsRecordDecl(), Name, Offset)) {
+ if (const FieldDecl *Field = FindFlexibleArrayMemberFieldAndOffset(
+ Ctx, Ty->getAsRecordDecl(), FAMDecl, Offset)) {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
Offset += Layout.getFieldOffset(FieldNo);
return Field;
@@ -930,12 +931,14 @@
// Get the flexible array member Decl.
const RecordDecl *OuterRD = nullptr;
- std::string FAMName;
+ const FieldDecl *FAMDecl = nullptr;
if (const auto *ME = dyn_cast<MemberExpr>(Base)) {
// Check if \p Base is referencing the FAM itself.
const ValueDecl *VD = ME->getMemberDecl();
OuterRD = VD->getDeclContext()->getOuterLexicalRecordContext();
- FAMName = VD->getNameAsString();
+ FAMDecl = dyn_cast<FieldDecl>(VD);
+ if (!FAMDecl)
+ return nullptr;
} else if (const auto *DRE = dyn_cast<DeclRefExpr>(Base)) {
// Check if we're pointing to the whole struct.
QualType Ty = DRE->getDecl()->getType();
@@ -974,9 +977,11 @@
if (!OuterRD)
return nullptr;
+ // We call FindFlexibleArrayMemberAndOffset even if FAMDecl is non-null to
+ // get its offset.
uint64_t Offset = 0;
- const FieldDecl *FAMDecl =
- FindFlexibleArrayMemberField(Ctx, OuterRD, FAMName, Offset);
+ FAMDecl =
+ FindFlexibleArrayMemberFieldAndOffset(Ctx, OuterRD, FAMDecl, Offset);
Offset = Ctx.toCharUnitsFromBits(Offset).getQuantity();
if (!FAMDecl || !FAMDecl->getType()->isCountAttributedType())
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index ff18733..a751649 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -3204,12 +3204,12 @@
llvm::Value *Index, QualType IndexType,
QualType IndexedType, bool Accessed);
- // Find a struct's flexible array member. It may be embedded inside multiple
- // sub-structs, but must still be the last field.
- const FieldDecl *FindFlexibleArrayMemberField(ASTContext &Ctx,
- const RecordDecl *RD,
- StringRef Name,
- uint64_t &Offset);
+ // Find a struct's flexible array member and get its offset. It may be
+ // embedded inside multiple sub-structs, but must still be the last field.
+ const FieldDecl *
+ FindFlexibleArrayMemberFieldAndOffset(ASTContext &Ctx, const RecordDecl *RD,
+ const FieldDecl *FAMDecl,
+ uint64_t &Offset);
/// Find the FieldDecl specified in a FAM's "counted_by" attribute. Returns
/// \p nullptr if either the attribute or the field doesn't exist.
