https://github.com/dougsonos created
https://github.com/llvm/llvm-project/pull/121525
`FunctionEffectsRef::get()` is supposed to strip off layers of indirection
(pointers/references, type sugar) to get to a `FunctionProtoType` (if any) and
return its effects (if any).
It wasn't correctly dealing with situations where the compiler implicitly
converts an array to a pointer.
This fixes the immediate bug by checking for array types, though I do wonder if
this still isn't sufficient if the array type is wrapped in sugar...
>From 6abcaf1be17d6f8b4412a20347f19972a7b73d91 Mon Sep 17 00:00:00 2001
From: Doug Wyatt <dwy...@apple.com>
Date: Thu, 2 Jan 2025 14:28:48 -0800
Subject: [PATCH] [Clang] FunctionEffects: Correctly navigate through array
types in FunctionEffectsRef::get().
---
clang/include/clang/AST/Type.h | 17 +++++++++++++----
.../test/Sema/attr-nonblocking-constraints.cpp | 10 ++++++++++
2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index 09c98f642852fc..782c32f41852e2 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -8836,13 +8836,22 @@ void FixedPointValueToString(SmallVectorImpl<char>
&Str, llvm::APSInt Val,
unsigned Scale);
inline FunctionEffectsRef FunctionEffectsRef::get(QualType QT) {
+ const Type *TypePtr = QT.getTypePtr();
while (true) {
- QualType Pointee = QT->getPointeeType();
- if (Pointee.isNull())
+ // Note that getPointeeType() seems to successfully navigate some
constructs
+ // for which isAnyPointerType() returns false (e.g.
+ // pointer-to-member-function).
+ QualType Pointee = TypePtr->getPointeeType();
+ if (Pointee.isNull()) {
+ if (TypePtr->isArrayType()) {
+ TypePtr = TypePtr->getBaseElementTypeUnsafe();
+ continue;
+ }
break;
- QT = Pointee;
+ }
+ TypePtr = Pointee.getTypePtr();
}
- if (const auto *FPT = QT->getAs<FunctionProtoType>())
+ if (const auto *FPT = TypePtr->getAs<FunctionProtoType>())
return FPT->getFunctionEffects();
return {};
}
diff --git a/clang/test/Sema/attr-nonblocking-constraints.cpp
b/clang/test/Sema/attr-nonblocking-constraints.cpp
index bbc909f627f4c3..8304a38f9af500 100644
--- a/clang/test/Sema/attr-nonblocking-constraints.cpp
+++ b/clang/test/Sema/attr-nonblocking-constraints.cpp
@@ -246,6 +246,16 @@ void PTMFTester::convert() [[clang::nonblocking]]
(this->*mConvertFunc)();
}
+// Allow implicit conversion from array to pointer.
+void nb14(unsigned idx) [[clang::nonblocking]]
+{
+ using FP = void (*)() [[clang::nonblocking]];
+ auto nb = +[]() [[clang::nonblocking]] {};
+
+ FP array[4] = { nb, nb, nb, nb };
+ FP f = array[idx]; // This should not generate a warning.
+}
+
// Block variables
void nb17(void (^blk)() [[clang::nonblocking]]) [[clang::nonblocking]] {
blk();
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