https://github.com/awilfox created
https://github.com/llvm/llvm-project/pull/111995
On big-endian systems, narrow casting will read the higher bits of the value.
LazyOffsetPtr's `getAddressOfPointer` returns the address-of `Ptr` which was
unconditionally a 64-bit value. On 32-bit big endian systems, reading this
value as a 32-bit pointer returns invalid data.
Fixes: bc73ef0031 ("PR60985: Fix merging of lambda closure types across
modules.")
Closes: #111993
>From 3c9198421a44f32d00c2ebe4ee0bf5a6ec67e9ac Mon Sep 17 00:00:00 2001
From: "A. Wilcox" <awil...@wilcox-tech.com>
Date: Fri, 11 Oct 2024 07:54:43 -0500
Subject: [PATCH] [clang] LazyOffsetPtr: Use native pointer width
On big-endian systems, narrow casting will read the higher bits of the
value. LazyOffsetPtr's `getAddressOfPointer` returns the address-of
`Ptr` which was unconditionally a 64-bit value. On 32-bit big endian
systems, reading this value as a 32-bit pointer returns invalid data.
Fixes: bc73ef0031 ("PR60985: Fix merging of lambda closure types across
modules.")
Closes: #111993
---
clang/include/clang/AST/ExternalASTSource.h | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/clang/include/clang/AST/ExternalASTSource.h
b/clang/include/clang/AST/ExternalASTSource.h
index 385c32edbae0fd..f5ce1a916fbee8 100644
--- a/clang/include/clang/AST/ExternalASTSource.h
+++ b/clang/include/clang/AST/ExternalASTSource.h
@@ -326,25 +326,25 @@ struct LazyOffsetPtr {
///
/// If the low bit is clear, a pointer to the AST node. If the low
/// bit is set, the upper 63 bits are the offset.
- mutable uint64_t Ptr = 0;
+ mutable uintptr_t Ptr = 0;
public:
LazyOffsetPtr() = default;
- explicit LazyOffsetPtr(T *Ptr) : Ptr(reinterpret_cast<uint64_t>(Ptr)) {}
+ explicit LazyOffsetPtr(T *Ptr) : Ptr(reinterpret_cast<uintptr_t>(Ptr)) {}
- explicit LazyOffsetPtr(uint64_t Offset) : Ptr((Offset << 1) | 0x01) {
- assert((Offset << 1 >> 1) == Offset && "Offsets must require < 63 bits");
+ explicit LazyOffsetPtr(uintptr_t Offset) : Ptr((Offset << 1) | 0x01) {
+ assert((Offset << 1 >> 1) == Offset && "Offsets must fit in addressable
bits");
if (Offset == 0)
Ptr = 0;
}
LazyOffsetPtr &operator=(T *Ptr) {
- this->Ptr = reinterpret_cast<uint64_t>(Ptr);
+ this->Ptr = reinterpret_cast<uintptr_t>(Ptr);
return *this;
}
- LazyOffsetPtr &operator=(uint64_t Offset) {
- assert((Offset << 1 >> 1) == Offset && "Offsets must require < 63 bits");
+ LazyOffsetPtr &operator=(uintptr_t Offset) {
+ assert((Offset << 1 >> 1) == Offset && "Offsets must fit in addressable
bits");
if (Offset == 0)
Ptr = 0;
else
@@ -375,7 +375,7 @@ struct LazyOffsetPtr {
if (isOffset()) {
assert(Source &&
"Cannot deserialize a lazy pointer without an AST source");
- Ptr = reinterpret_cast<uint64_t>((Source->*Get)(OffsT(Ptr >> 1)));
+ Ptr = reinterpret_cast<uintptr_t>((Source->*Get)(OffsT(Ptr >> 1)));
}
return reinterpret_cast<T*>(Ptr);
}
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