[compiler-rt] 4c87793 - sanitizer_allocator.cpp: Ensure at least sizeof(void*) alignment

[via llvm-commits]

Author: Alexander Richardson
Date: 2024-10-24T14:09:05-07:00
New Revision: 4c8779388fd2f25730a1b044f9f10d6717833fce

URL: https://github.com/llvm/llvm-project/commit/4c8779388fd2f25730a1b044f9f10d6717833fce
DIFF: https://github.com/llvm/llvm-project/commit/4c8779388fd2f25730a1b044f9f10d6717833fce.diff

LOG: sanitizer_allocator.cpp: Ensure at least sizeof(void*) alignment

Some platforms (e.g. 64-bit CHERI) have stronger alignment requirements
on values returned from allocators. For all other platforms this does
not result in any functional change.

Reviewed By: cjappl, vitalybuka

Pull Request: https://github.com/llvm/llvm-project/pull/84440

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_allocator.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cpp
index 1d5058c81acbcd..9d899371c2dd90 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cpp
@@ -59,7 +59,7 @@ static void *RawInternalAlloc(uptr size, InternalAllocatorCache *cache,
 
 static void *RawInternalRealloc(void *ptr, uptr size,
                                 InternalAllocatorCache *cache) {
-  uptr alignment = 8;
+  constexpr usize alignment = Max<usize>(8, sizeof(void *));
   if (cache == 0) {
     SpinMutexLock l(&internal_allocator_cache_mu);
     return internal_allocator()->Reallocate(&internal_allocator_cache, ptr,
@@ -137,7 +137,8 @@ void InternalAllocatorUnlock() SANITIZER_NO_THREAD_SAFETY_ANALYSIS {
 }
 
 // LowLevelAllocator
-constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
+constexpr usize kLowLevelAllocatorDefaultAlignment =
+    Max<usize>(8, sizeof(void *));
 constexpr uptr kMinNumPagesRounded = 16;
 constexpr uptr kMinRoundedSize = 65536;
 static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;