llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Bill Wendling (bwendling)
<details>
<summary>Changes</summary>
A struct that declares an inner struct, but no fields, won't have a field
count. So getting the offset of the inner struct fails. This happens in both C
and C++:
struct foo {
struct bar {
int Quantizermatrix[];
};
};
Here 'struct foo' has no fields.
Fixes: https://github.com/llvm/llvm-project/issues/88931
---
Full diff: https://github.com/llvm/llvm-project/pull/89126.diff
3 Files Affected:
- (modified) clang/lib/CodeGen/CGBuiltin.cpp (+14-1)
- (added) clang/test/CodeGen/attr-counted-by-pr88931.c (+22)
- (added) clang/test/CodeGen/attr-counted-by-pr88931.cpp (+21)
``````````diff
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index a05874e63c73c2..bee12c4469e7f7 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -829,6 +829,9 @@ const FieldDecl
*CodeGenFunction::FindFlexibleArrayMemberField(
unsigned FieldNo = 0;
bool IsUnion = RD->isUnion();
+ if (RD->isImplicit())
+ return nullptr;
+
for (const Decl *D : RD->decls()) {
if (const auto *Field = dyn_cast<FieldDecl>(D);
Field && (Name.empty() || Field->getNameAsString() == Name) &&
@@ -844,7 +847,17 @@ const FieldDecl
*CodeGenFunction::FindFlexibleArrayMemberField(
if (const FieldDecl *Field =
FindFlexibleArrayMemberField(Ctx, Record, Name, Offset)) {
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
- Offset += Layout.getFieldOffset(FieldNo);
+ if (Layout.getFieldCount()) {
+ // A struct that holds only an inner struct won't have any fields.
E.g.
+ //
+ // struct foo {
+ // struct bar {
+ // int count;
+ // int array[];
+ // };
+ // };
+ Offset += Layout.getFieldOffset(FieldNo);
+ }
return Field;
}
diff --git a/clang/test/CodeGen/attr-counted-by-pr88931.c
b/clang/test/CodeGen/attr-counted-by-pr88931.c
new file mode 100644
index 00000000000000..baa1bbc8397456
--- /dev/null
+++ b/clang/test/CodeGen/attr-counted-by-pr88931.c
@@ -0,0 +1,22 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
UTC_ARGS: --version 4
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -O2
-Wno-missing-declarations -emit-llvm -o - %s | FileCheck %s
+
+struct foo {
+ struct bar {
+ int count;
+ int array[] __attribute__((counted_by(count)));
+ };
+};
+
+void init(void * __attribute__((pass_dynamic_object_size(0))));
+
+// CHECK-LABEL: define dso_local void @test1(
+// CHECK-SAME: ptr noundef [[P:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT: entry:
+// CHECK-NEXT: [[ARRAY:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 4
+// CHECK-NEXT: tail call void @init(ptr noundef nonnull [[ARRAY]], i64
noundef -1) #[[ATTR2:[0-9]+]]
+// CHECK-NEXT: ret void
+//
+void test1(struct bar *p) {
+ init(p->array);
+}
diff --git a/clang/test/CodeGen/attr-counted-by-pr88931.cpp
b/clang/test/CodeGen/attr-counted-by-pr88931.cpp
new file mode 100644
index 00000000000000..2a8cc1d07e50d9
--- /dev/null
+++ b/clang/test/CodeGen/attr-counted-by-pr88931.cpp
@@ -0,0 +1,21 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
UTC_ARGS: --version 4
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -O2 -Wall -emit-llvm -o -
%s | FileCheck %s
+
+struct foo {
+ struct bar {
+ int array[];
+ bar();
+ };
+};
+
+void init(void * __attribute__((pass_dynamic_object_size(0))));
+
+// CHECK-LABEL: define dso_local void @_ZN3foo3barC1Ev(
+// CHECK-SAME: ptr noundef nonnull align 4 dereferenceable(1) [[THIS:%.*]])
unnamed_addr #[[ATTR0:[0-9]+]] align 2 {
+// CHECK-NEXT: entry:
+// CHECK-NEXT: tail call void @_Z4initPvU25pass_dynamic_object_size0(ptr
noundef nonnull [[THIS]], i64 noundef -1) #[[ATTR2:[0-9]+]]
+// CHECK-NEXT: ret void
+//
+foo::bar::bar() {
+ init(array);
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/89126
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