[Clang] Loop over FieldDecls instead of all Decls (#99574)

Summary:
Only FieldDecls are important when determining GEP indices. A struct
defined within another struct has the same semantics as if it were
defined outside of the struct. So there's no need to look into
RecordDecls that aren't a field.

See commit 5bcf31e ("[Clang] Loop over FieldDecls instead of all
Decls (#89453)")

Fixes 2039.

Test Plan: 

Reviewers: 

Subscribers: 

Tasks: 

Tags: 


Differential Revision: https://phabricator.intern.facebook.com/D60250945

Author: bwendling

clang/lib/CodeGen/CGExpr.cpp

@@ -1071,21 +1071,20 @@ using RecIndicesTy =
     SmallVector<std::pair<const RecordDecl *, llvm::Value *>, 8>;
 
 static bool getGEPIndicesToField(CodeGenFunction &CGF, const RecordDecl *RD,
-                                 const FieldDecl *FD, RecIndicesTy &Indices) {
+                                 const FieldDecl *Field,
+                                 RecIndicesTy &Indices) {
   const CGRecordLayout &Layout = CGF.CGM.getTypes().getCGRecordLayout(RD);
   int64_t FieldNo = -1;
-  for (const Decl *D : RD->decls()) {
-    if (const auto *Field = dyn_cast<FieldDecl>(D)) {
-      FieldNo = Layout.getLLVMFieldNo(Field);
-      if (FD == Field) {
-        Indices.emplace_back(std::make_pair(RD, CGF.Builder.getInt32(FieldNo)));
-        return true;
-      }
+  for (const FieldDecl *FD : RD->fields()) {
+    FieldNo = Layout.getLLVMFieldNo(FD);
+    if (FD == Field) {
+      Indices.emplace_back(std::make_pair(RD, CGF.Builder.getInt32(FieldNo)));
+      return true;
     }
 
-    if (const auto *Record = dyn_cast<RecordDecl>(D)) {
-      ++FieldNo;
-      if (getGEPIndicesToField(CGF, Record, FD, Indices)) {
+    QualType Ty = FD->getType();
+    if (Ty->isRecordType()) {
+      if (getGEPIndicesToField(CGF, Ty->getAsRecordDecl(), Field, Indices)) {
         if (RD->isUnion())
           FieldNo = 0;
         Indices.emplace_back(std::make_pair(RD, CGF.Builder.getInt32(FieldNo)));

clang/test/CodeGen/attr-counted-by.c

@@ -1852,3 +1852,57 @@ struct annotated_struct_array {
 void test29(struct annotated_struct_array *ann, int idx1, int idx2) {
   ann->ann_array[idx1]->array[idx2] = __builtin_dynamic_object_size(ann->ann_array[idx1]->array, 1);
 }
+
+typedef struct {
+  char __padding[0];
+} test30_spinlock_t;
+
+struct test30_struct {
+  struct test30_decl *name_node;
+  int priv_len;
+  test30_spinlock_t pcpu_refcnt;
+  char priv[] __counted_by(priv_len);
+};
+
+// SANITIZE-WITH-ATTR-LABEL: define dso_local void @test30(
+// SANITIZE-WITH-ATTR-SAME: ptr noundef [[PTR:%.*]], i32 noundef [[IDX:%.*]]) local_unnamed_addr #[[ATTR5]] {
+// SANITIZE-WITH-ATTR-NEXT:  entry:
+// SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = zext i32 [[IDX]] to i64, !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB39:[0-9]+]], i64 [[TMP0]]) #[[ATTR10]], !nosanitize [[META2]]
+// SANITIZE-WITH-ATTR-NEXT:    unreachable, !nosanitize [[META2]]
+//
+// NO-SANITIZE-WITH-ATTR-LABEL: define dso_local void @test30(
+// NO-SANITIZE-WITH-ATTR-SAME: ptr nocapture noundef [[PTR:%.*]], i32 noundef [[IDX:%.*]]) local_unnamed_addr #[[ATTR1]] {
+// NO-SANITIZE-WITH-ATTR-NEXT:  entry:
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i64 8
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOT_COUNTED_BY_LOAD:%.*]] = load i32, ptr [[DOT_COUNTED_BY_GEP]], align 4
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP0:%.*]] = tail call i32 @llvm.smax.i32(i32 [[DOT_COUNTED_BY_LOAD]], i32 4)
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[DOTINV:%.*]] = icmp slt i32 [[DOT_COUNTED_BY_LOAD]], 0
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP1:%.*]] = trunc i32 [[TMP0]] to i8
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[TMP2:%.*]] = add i8 [[TMP1]], 12
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[CONV:%.*]] = select i1 [[DOTINV]], i8 0, i8 [[TMP2]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[PCPU_REFCNT:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i64 12
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[IDXPROM:%.*]] = sext i32 [[IDX]] to i64
+// NO-SANITIZE-WITH-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [0 x i8], ptr [[PCPU_REFCNT]], i64 0, i64 [[IDXPROM]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    store i8 [[CONV]], ptr [[ARRAYIDX]], align 1, !tbaa [[TBAA6]]
+// NO-SANITIZE-WITH-ATTR-NEXT:    ret void
+//
+// SANITIZE-WITHOUT-ATTR-LABEL: define dso_local void @test30(
+// SANITIZE-WITHOUT-ATTR-SAME: ptr noundef [[PTR:%.*]], i32 noundef [[IDX:%.*]]) local_unnamed_addr #[[ATTR3]] {
+// SANITIZE-WITHOUT-ATTR-NEXT:  entry:
+// SANITIZE-WITHOUT-ATTR-NEXT:    [[TMP0:%.*]] = zext i32 [[IDX]] to i64, !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR-NEXT:    tail call void @__ubsan_handle_out_of_bounds_abort(ptr nonnull @[[GLOB15:[0-9]+]], i64 [[TMP0]]) #[[ATTR8]], !nosanitize [[META9]]
+// SANITIZE-WITHOUT-ATTR-NEXT:    unreachable, !nosanitize [[META9]]
+//
+// NO-SANITIZE-WITHOUT-ATTR-LABEL: define dso_local void @test30(
+// NO-SANITIZE-WITHOUT-ATTR-SAME: ptr noundef [[PTR:%.*]], i32 noundef [[IDX:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:  entry:
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    [[PCPU_REFCNT:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i64 12
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    [[IDXPROM:%.*]] = sext i32 [[IDX]] to i64
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [0 x i8], ptr [[PCPU_REFCNT]], i64 0, i64 [[IDXPROM]]
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    store i8 -1, ptr [[ARRAYIDX]], align 1, !tbaa [[TBAA6]]
+// NO-SANITIZE-WITHOUT-ATTR-NEXT:    ret void
+//
+void test30(struct test30_struct *ptr, int idx) {
+  ptr->pcpu_refcnt.__padding[idx] = __builtin_dynamic_object_size(ptr, 1);
+}