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[Clang] Fix 'counted_by' for nested struct pointers #110437

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[Clang] Fix 'counted_by' for nested struct pointers #110437

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8 changes: 4 additions & 4 deletions clang/lib/CodeGen/CGExpr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1165,15 +1165,15 @@ llvm::Value *CodeGenFunction::EmitLoadOfCountedByField(
Res = EmitDeclRefLValue(DRE).getPointer(*this);
Res = Builder.CreateAlignedLoad(ConvertType(DRE->getType()), Res,
getPointerAlign(), "dre.load");
} else if (const MemberExpr *ME = dyn_cast<MemberExpr>(StructBase)) {
LValue LV = EmitMemberExpr(ME);
Address Addr = LV.getAddress();
Res = Addr.emitRawPointer(*this);
} else if (StructBase->getType()->isPointerType()) {
LValueBaseInfo BaseInfo;
TBAAAccessInfo TBAAInfo;
Address Addr = EmitPointerWithAlignment(StructBase, &BaseInfo, &TBAAInfo);
Res = Addr.emitRawPointer(*this);
} else if (const MemberExpr *ME = dyn_cast<MemberExpr>(StructBase)) {
LValue LV = EmitMemberExpr(ME);
Address Addr = LV.getAddress();
Res = Addr.emitRawPointer(*this);
} else {
return nullptr;
}
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40 changes: 40 additions & 0 deletions clang/test/CodeGen/attr-counted-by-pr110385.c
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@@ -0,0 +1,40 @@
// 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

// See #110385
// Based on reproducer from Kees Cook:
// https://lore.kernel.org/all/202409170436.C3C6E7F7A@keescook/

struct variable {
int a;
int b;
int length;
short array[] __attribute__((counted_by(length)));
};

struct bucket {
int a;
struct variable *growable;
int b;
};

void init(void * __attribute__((pass_dynamic_object_size(0))));

// CHECK-LABEL: define dso_local void @test1(
// CHECK-SAME: ptr nocapture noundef readonly [[FOO:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[GROWABLE:%.*]] = getelementptr inbounds nuw i8, ptr [[FOO]], i64 8
// CHECK-NEXT: [[TMP0:%.*]] = load ptr, ptr [[GROWABLE]], align 8, !tbaa [[TBAA2:![0-9]+]]
// CHECK-NEXT: [[ARRAY:%.*]] = getelementptr inbounds nuw i8, ptr [[TMP0]], i64 12
// CHECK-NEXT: [[DOT_COUNTED_BY_GEP:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i64 8
// CHECK-NEXT: [[DOT_COUNTED_BY_LOAD:%.*]] = load i32, ptr [[DOT_COUNTED_BY_GEP]], align 4
// CHECK-NEXT: [[TMP1:%.*]] = sext i32 [[DOT_COUNTED_BY_LOAD]] to i64
// CHECK-NEXT: [[TMP2:%.*]] = shl nsw i64 [[TMP1]], 1
// CHECK-NEXT: [[TMP3:%.*]] = icmp sgt i32 [[DOT_COUNTED_BY_LOAD]], -1
// CHECK-NEXT: [[TMP4:%.*]] = select i1 [[TMP3]], i64 [[TMP2]], i64 0
// CHECK-NEXT: tail call void @init(ptr noundef nonnull [[ARRAY]], i64 noundef [[TMP4]]) #[[ATTR2:[0-9]+]]
// CHECK-NEXT: ret void
//
void test1(struct bucket *foo) {
init(foo->growable->array);
}
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