[PATCH] D150892: [clang][ExprConstant] fix __builtin_object_size for flexible array members
Nick Desaulniers via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Thu May 18 11:40:13 PDT 2023
nickdesaulniers updated this revision to Diff 523476.
nickdesaulniers added a comment.
- add release note
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D150892/new/
https://reviews.llvm.org/D150892
Files:
clang/docs/ReleaseNotes.rst
clang/lib/AST/ExprConstant.cpp
clang/test/CodeGen/object-size.c
Index: clang/test/CodeGen/object-size.c
===================================================================
--- clang/test/CodeGen/object-size.c
+++ clang/test/CodeGen/object-size.c
@@ -525,6 +525,16 @@
gi = OBJECT_SIZE_BUILTIN(&dsv[9].snd[0], 1);
}
+// CHECK-LABEL: @test32
+static struct DynStructVar D = {
+ .fst = {},
+ .snd = { 0, 1, 2, },
+};
+unsigned long test32(void) {
+ // CHECK: ret i64 19
+ return __builtin_object_size(&D, 1);
+}
+
// CHECK-LABEL: @PR30346
void PR30346(void) {
struct sa_family_t {};
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -11732,7 +11732,14 @@
auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
return false;
- return HandleSizeof(Info, ExprLoc, Ty, Result);
+ bool Ret = HandleSizeof(Info, ExprLoc, Ty, Result);
+ if (Ty->isStructureType() &&
+ Ty->getAsStructureType()->getDecl()->hasFlexibleArrayMember()) {
+ const auto *VD =
+ cast<VarDecl>(LVal.getLValueBase().get<const ValueDecl *>());
+ Result += VD->getFlexibleArrayInitChars(Info.Ctx);
+ }
+ return Ret;
};
// We want to evaluate the size of the entire object. This is a valid fallback
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -51,6 +51,10 @@
foo: asm goto ("# %0 %1"::"i"(&&foo)::foo);
+- ``__builtin_object_size`` now adds the ``sizeof`` the elements specified in
+ designated initializers of flexible array members. This change is more
+ consistent with the behavior of GCC.
+
C++ Specific Potentially Breaking Changes
-----------------------------------------
- Clang won't search for coroutine_traits in std::experimental namespace any more.
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