[llvm-branch-commits] [CodeGen][CFI] Generalize transparent union parameters (PR #158193)
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llvm-branch-commits at lists.llvm.org
Thu Sep 11 21:46:26 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Vitaly Buka (vitalybuka)
<details>
<summary>Changes</summary>
According GCC documentation transparent union
calling convention is the same as the type of the
first member of the union.
C++ ignores attribute.
---
Full diff: https://github.com/llvm/llvm-project/pull/158193.diff
5 Files Affected:
- (modified) clang/lib/CodeGen/CodeGenModule.cpp (+17-1)
- (modified) clang/test/CodeGen/cfi-icall-generalize.c (+4-4)
- (modified) clang/test/CodeGen/cfi-icall-normalize2.c (+2-2)
- (modified) clang/test/CodeGen/kcfi-generalize.c (+4-4)
- (modified) clang/test/CodeGen/kcfi-normalize.c (+6-4)
``````````diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c647003ff389d..46dbd85665e5d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2339,13 +2339,29 @@ llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
}
+static QualType GeneralizeTransparentUnion(QualType Ty) {
+ const RecordType *UT = Ty->getAsUnionType();
+ if (!UT)
+ return Ty;
+ const RecordDecl *UD = UT->getOriginalDecl()->getDefinitionOrSelf();
+ if (!UD->hasAttr<TransparentUnionAttr>())
+ return Ty;
+ for (const auto *it : UD->fields()) {
+ return it->getType();
+ }
+ return Ty;
+}
+
+static QualType GeneralizeTransparentUnion(QualType Ty) {
+}
+
// Generalize pointer types to a void pointer with the qualifiers of the
// originally pointed-to type, e.g. 'const char *' and 'char * const *'
// generalize to 'const void *' while 'char *' and 'const char **' generalize to
// 'void *'.
static QualType GeneralizeType(ASTContext &Ctx, QualType Ty,
bool GeneralizePointers) {
- // TODO: Add other generalizations.
+ Ty = GeneralizeTransparentUnion(Ty);
if (!GeneralizePointers || !Ty->isPointerType())
return Ty;
diff --git a/clang/test/CodeGen/cfi-icall-generalize.c b/clang/test/CodeGen/cfi-icall-generalize.c
index 116a99e4e2859..5359134805198 100644
--- a/clang/test/CodeGen/cfi-icall-generalize.c
+++ b/clang/test/CodeGen/cfi-icall-generalize.c
@@ -22,13 +22,13 @@ union Union {
// CHECK: define{{.*}} void @uni({{.*}} !type [[TYPE2:![0-9]+]] !type [[TYPE2_GENERALIZED:![0-9]+]]
void uni(void (*fn)(union Union), union Union arg1) {
- // UNGENERALIZED: call i1 @llvm.type.test(ptr {{.*}}, metadata !"_ZTSFv5UnionE")
- // GENERALIZED: call i1 @llvm.type.test(ptr {{.*}}, metadata !"_ZTSFv5UnionE.generalized")
+ // UNGENERALIZED: call i1 @llvm.type.test(ptr {{.*}}, metadata !"_ZTSFvPcE")
+ // GENERALIZED: call i1 @llvm.type.test(ptr {{.*}}, metadata !"_ZTSFvPvE.generalized")
fn(arg1);
}
// CHECK: [[TYPE]] = !{i64 0, !"_ZTSFPPiPKcPS2_E"}
// CHECK: [[TYPE_GENERALIZED]] = !{i64 0, !"_ZTSFPvPKvS_E.generalized"}
-// CHECK: [[TYPE2]] = !{i64 0, !"_ZTSFvPFv5UnionES_E"}
-// CHECK: [[TYPE2_GENERALIZED]] = !{i64 0, !"_ZTSFvPv5UnionE.generalized"}
+// CHECK: [[TYPE2]] = !{i64 0, !"_ZTSFvPFv5UnionEPcE"}
+// CHECK: [[TYPE2_GENERALIZED]] = !{i64 0, !"_ZTSFvPvS_E.generalized"}
diff --git a/clang/test/CodeGen/cfi-icall-normalize2.c b/clang/test/CodeGen/cfi-icall-normalize2.c
index c88ecc9f0c3f7..b9d9af7c8a47b 100644
--- a/clang/test/CodeGen/cfi-icall-normalize2.c
+++ b/clang/test/CodeGen/cfi-icall-normalize2.c
@@ -32,11 +32,11 @@ union Union {
void uni(void (*fn)(union Union), union Union arg1) {
// CHECK-LABEL: define{{.*}}uni
// CHECK-SAME: {{.*}}!type ![[TYPE4:[0-9]+]] !type !{{[0-9]+}}
- // CHECK: call i1 @llvm.type.test({{i8\*|ptr}} {{%f|%0}}, metadata !"_ZTSFv5UnionE.normalized")
+ // CHECK: call i1 @llvm.type.test({{i8\*|ptr}} {{%f|%0}}, metadata !"_ZTSFvPu2i8E.normalized")
fn(arg1);
}
// CHECK: ![[TYPE1]] = !{i64 0, !"_ZTSFvPFvu3i32ES_E.normalized"}
// CHECK: ![[TYPE2]] = !{i64 0, !"_ZTSFvPFvu3i32S_ES_S_E.normalized"}
// CHECK: ![[TYPE3]] = !{i64 0, !"_ZTSFvPFvu3i32S_S_ES_S_S_E.normalized"}
-// CHECK: ![[TYPE4]] = !{i64 0, !"_ZTSFvPFv5UnionES_E.normalized"}
+// CHECK: ![[TYPE4]] = !{i64 0, !"_ZTSFvPFv5UnionEPu2i8E.normalized"}
diff --git a/clang/test/CodeGen/kcfi-generalize.c b/clang/test/CodeGen/kcfi-generalize.c
index 89b298f3e2faa..24e054549d527 100644
--- a/clang/test/CodeGen/kcfi-generalize.c
+++ b/clang/test/CodeGen/kcfi-generalize.c
@@ -33,8 +33,8 @@ union Union {
// CHECK: define{{.*}} void @uni({{.*}} !kcfi_type [[TYPE2:![0-9]+]]
void uni(void (*fn)(union Union), union Union arg1) {
- // UNGENERALIZED: call {{.*}} [ "kcfi"(i32 -1037059548) ]
- // GENERALIZED: call {{.*}} [ "kcfi"(i32 422130955) ]
+ // UNGENERALIZED: call {{.*}} [ "kcfi"(i32 -587217045) ]
+ // GENERALIZED: call {{.*}} [ "kcfi"(i32 2139530422) ]
fn(arg1);
}
@@ -44,5 +44,5 @@ void uni(void (*fn)(union Union), union Union arg1) {
// UNGENERALIZED: [[TYPE3]] = !{i32 874141567}
// GENERALIZED: [[TYPE3]] = !{i32 954385378}
-// UNGENERALIZED: [[TYPE2]] = !{i32 981319178}
-// GENERALIZED: [[TYPE2]] = !{i32 -1599950473}
\ No newline at end of file
+// UNGENERALIZED: [[TYPE2]] = !{i32 -1619636625}
+// GENERALIZED: [[TYPE2]] = !{i32 -125078496}
\ No newline at end of file
diff --git a/clang/test/CodeGen/kcfi-normalize.c b/clang/test/CodeGen/kcfi-normalize.c
index cde784962d11a..08f5249b6d6c3 100644
--- a/clang/test/CodeGen/kcfi-normalize.c
+++ b/clang/test/CodeGen/kcfi-normalize.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers -x c++ -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers -o - %s | FileCheck %s --check-prefixes=CHECK,C
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers -x c++ -o - %s | FileCheck %s --check-prefixes=CHECK,CPP
#if !__has_feature(kcfi)
#error Missing kcfi?
#endif
@@ -36,7 +36,8 @@ union Union {
void uni(void (*fn)(union Union), union Union arg1) {
// CHECK-LABEL: define{{.*}}uni
// CHECK-SAME: {{.*}}!kcfi_type ![[TYPE4:[0-9]+]]
- // CHECK: call void %0(ptr %1) [ "kcfi"(i32 -1430221633) ]
+ // C: call void %0(ptr %1) [ "kcfi"(i32 1819770848) ]
+ // CPP: call void %0(ptr %1) [ "kcfi"(i32 -1430221633) ]
fn(arg1);
}
@@ -44,4 +45,5 @@ void uni(void (*fn)(union Union), union Union arg1) {
// CHECK: ![[TYPE1]] = !{i32 -1143117868}
// CHECK: ![[TYPE2]] = !{i32 -460921415}
// CHECK: ![[TYPE3]] = !{i32 -333839615}
-// CHECK: ![[TYPE4]] = !{i32 1766237188}
\ No newline at end of file
+// C: ![[TYPE4]] = !{i32 -650530463}
+// CPP: ![[TYPE4]] = !{i32 1766237188}
\ No newline at end of file
``````````
</details>
https://github.com/llvm/llvm-project/pull/158193
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