[libc-commits] [libc] 8ea6b73 - [libc] Fix alignment issue for HermeticTestUtils.cpp. (#128426)

[via libc-commits]

Author: lntue
Date: 2025-02-23T13:41:51-05:00
New Revision: 8ea6b735a64da7d97a556832209c0bb70ea00a21

URL: https://github.com/llvm/llvm-project/commit/8ea6b735a64da7d97a556832209c0bb70ea00a21
DIFF: https://github.com/llvm/llvm-project/commit/8ea6b735a64da7d97a556832209c0bb70ea00a21.diff

LOG: [libc] Fix alignment issue for HermeticTestUtils.cpp. (#128426)

Full build precommit bots were failing due to mis-alignment of atomics
in hermetic tests. This PR enforces the alignment for the bump allocator
of hermetic test framework.

Fixes https://github.com/llvm/llvm-project/issues/128185.

Added: 
    

Modified: 
    libc/test/UnitTest/HermeticTestUtils.cpp

Removed: 
    


################################################################################
diff  --git a/libc/test/UnitTest/HermeticTestUtils.cpp b/libc/test/UnitTest/HermeticTestUtils.cpp
index 47f813b0b7a4e..a9494af746d52 100644
--- a/libc/test/UnitTest/HermeticTestUtils.cpp
+++ b/libc/test/UnitTest/HermeticTestUtils.cpp
@@ -33,6 +33,8 @@ int atexit(void (*func)(void));
 
 } // namespace LIBC_NAMESPACE_DECL
 
+constexpr uint64_t ALIGNMENT = alignof(uintptr_t);
+
 namespace {
 
 // Integration tests cannot use the SCUDO standalone allocator as SCUDO pulls
@@ -42,7 +44,7 @@ namespace {
 // which just hands out continuous blocks from a statically allocated chunk of
 // memory.
 static constexpr uint64_t MEMORY_SIZE = 65336;
-static uint8_t memory[MEMORY_SIZE];
+alignas(ALIGNMENT) static uint8_t memory[MEMORY_SIZE];
 static uint8_t *ptr = memory;
 
 } // anonymous namespace
@@ -74,8 +76,6 @@ void *memset(void *ptr, int value, size_t count) {
 // This is needed if the test was compiled with '-fno-use-cxa-atexit'.
 int atexit(void (*func)(void)) { return LIBC_NAMESPACE::atexit(func); }
 
-constexpr uint64_t ALIGNMENT = alignof(uintptr_t);
-
 void *malloc(size_t s) {
   // Keep the bump pointer aligned on an eight byte boundary.
   s = ((s + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT;