[clang] [CodeGen] Fix handling of nullptr in initializers (PR #137364)
Alexander Kornienko via cfe-commits
cfe-commits at lists.llvm.org
Fri Apr 25 11:54:52 PDT 2025
https://github.com/alexfh updated https://github.com/llvm/llvm-project/pull/137364
>From 5431de1664814a7a2dcc93695eed8745ae6bfef5 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 17:51:03 +0200
Subject: [PATCH 1/5] [CodeGen] Fix handling of nullptr in initializers
Fixes https://github.com/llvm/llvm-project/issues/137276.
---
clang/lib/CodeGen/CodeGenTypes.cpp | 6 ++++--
clang/test/CodeGenCXX/pr137276.cpp | 13 +++++++++++++
2 files changed, 17 insertions(+), 2 deletions(-)
create mode 100644 clang/test/CodeGenCXX/pr137276.cpp
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index b94c11802a268..d1b292f23c2d2 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -850,12 +850,14 @@ CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) {
}
bool CodeGenTypes::isPointerZeroInitializable(QualType T) {
- assert((T->isAnyPointerType() || T->isBlockPointerType()) && "Invalid type");
+ assert((T->isAnyPointerType() || T->isBlockPointerType() ||
+ T->isNullPtrType()) &&
+ "Invalid type");
return isZeroInitializable(T);
}
bool CodeGenTypes::isZeroInitializable(QualType T) {
- if (T->getAs<PointerType>())
+ if (T->getAs<PointerType>() || T->isNullPtrType())
return Context.getTargetNullPointerValue(T) == 0;
if (const auto *AT = Context.getAsArrayType(T)) {
diff --git a/clang/test/CodeGenCXX/pr137276.cpp b/clang/test/CodeGenCXX/pr137276.cpp
new file mode 100644
index 0000000000000..0664a121ad6a0
--- /dev/null
+++ b/clang/test/CodeGenCXX/pr137276.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-linux-gnu -emit-llvm -o - %s | FileCheck %s
+
+using ulong = unsigned long;
+template <class... Ts>
+void g(Ts... args) {
+ ulong arr[3] = {ulong(args)...};
+ (void)arr;
+}
+extern void f() {
+ g(nullptr, 17);
+}
+
+// CHECK: {{^}} store i64 0, ptr %arr, align 8{{$}}
>From a0e4f300a8171bec3a267c446e0a10dc1bf6f57f Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 19:21:59 +0200
Subject: [PATCH 2/5] Update CK_NullToPointer comment
---
clang/include/clang/AST/OperationKinds.def | 1 +
1 file changed, 1 insertion(+)
diff --git a/clang/include/clang/AST/OperationKinds.def b/clang/include/clang/AST/OperationKinds.def
index 790dd572a7c99..1c03610affffe 100644
--- a/clang/include/clang/AST/OperationKinds.def
+++ b/clang/include/clang/AST/OperationKinds.def
@@ -121,6 +121,7 @@ CAST_OPERATION(FunctionToPointerDecay)
/// CK_NullToPointer - Null pointer constant to pointer, ObjC
/// pointer, or block pointer.
/// (void*) 0
+/// (void*) nullptr
/// void (^block)() = 0;
CAST_OPERATION(NullToPointer)
>From 74e4ed26a4e88126fb0ebcd3a1ae3ca0b0f80f48 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 19:55:42 +0200
Subject: [PATCH 3/5] Move the test to nullptr.cpp, simplified it, added
CHECK-LABEL.
---
clang/test/CodeGenCXX/nullptr.cpp | 7 +++++++
clang/test/CodeGenCXX/pr137276.cpp | 13 -------------
2 files changed, 7 insertions(+), 13 deletions(-)
delete mode 100644 clang/test/CodeGenCXX/pr137276.cpp
diff --git a/clang/test/CodeGenCXX/nullptr.cpp b/clang/test/CodeGenCXX/nullptr.cpp
index 0d8837b216bec..3c35bb1b64a6f 100644
--- a/clang/test/CodeGenCXX/nullptr.cpp
+++ b/clang/test/CodeGenCXX/nullptr.cpp
@@ -70,3 +70,10 @@ namespace PR39528 {
void f(nullptr_t);
void g() { f(null); }
}
+
+// CHECK-LABEL: define {{.*}}pr137276
+// CHECK: {{^}} store i64 0, ptr %arr, align 8{{$}}
+void pr137276(nullptr_t np, int i) {
+ long arr[] = { long(np), i, 0 };
+ (void)arr;
+}
diff --git a/clang/test/CodeGenCXX/pr137276.cpp b/clang/test/CodeGenCXX/pr137276.cpp
deleted file mode 100644
index 0664a121ad6a0..0000000000000
--- a/clang/test/CodeGenCXX/pr137276.cpp
+++ /dev/null
@@ -1,13 +0,0 @@
-// RUN: %clang_cc1 -std=c++20 -triple x86_64-linux-gnu -emit-llvm -o - %s | FileCheck %s
-
-using ulong = unsigned long;
-template <class... Ts>
-void g(Ts... args) {
- ulong arr[3] = {ulong(args)...};
- (void)arr;
-}
-extern void f() {
- g(nullptr, 17);
-}
-
-// CHECK: {{^}} store i64 0, ptr %arr, align 8{{$}}
>From f5d1430379d2edc1ec27e2a8acd3926c75715926 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 20:29:06 +0200
Subject: [PATCH 4/5] Update CK_NullToPointer comment
---
clang/include/clang/AST/OperationKinds.def | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/include/clang/AST/OperationKinds.def b/clang/include/clang/AST/OperationKinds.def
index 1c03610affffe..4437c450a7097 100644
--- a/clang/include/clang/AST/OperationKinds.def
+++ b/clang/include/clang/AST/OperationKinds.def
@@ -121,7 +121,7 @@ CAST_OPERATION(FunctionToPointerDecay)
/// CK_NullToPointer - Null pointer constant to pointer, ObjC
/// pointer, or block pointer.
/// (void*) 0
-/// (void*) nullptr
+/// (std::nullptr_t) x
/// void (^block)() = 0;
CAST_OPERATION(NullToPointer)
>From c68b2efb185d2cd28fb63cdf35b74e2b5223c953 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh at google.com>
Date: Fri, 25 Apr 2025 20:54:42 +0200
Subject: [PATCH 5/5] Update OperationKinds.def
---
clang/include/clang/AST/OperationKinds.def | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/include/clang/AST/OperationKinds.def b/clang/include/clang/AST/OperationKinds.def
index 4437c450a7097..d33d608a16f24 100644
--- a/clang/include/clang/AST/OperationKinds.def
+++ b/clang/include/clang/AST/OperationKinds.def
@@ -119,9 +119,9 @@ CAST_OPERATION(ArrayToPointerDecay)
CAST_OPERATION(FunctionToPointerDecay)
/// CK_NullToPointer - Null pointer constant to pointer, ObjC
-/// pointer, or block pointer.
+/// pointer, or block pointer. The result of this conversion can
+/// still be a null pointer constant if it has type std::nullptr_t.
/// (void*) 0
-/// (std::nullptr_t) x
/// void (^block)() = 0;
CAST_OPERATION(NullToPointer)
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