[libcxx-commits] [PATCH] D85873: Add cold attribute to one time construction APIs

[Aditya Kumar via Phabricator via libcxx-commits]

hiraditya created this revision.
hiraditya added reviewers: mclow.lists, ldionne, jfb, yfeldblum.
Herald added subscribers: libcxx-commits, dexonsmith.
hiraditya requested review of this revision.

_cxa_guard_acquire is used for only one purpose, namely guarding local static variable initialization, and since that purpose is definitionally cold, it should be attributed as cold.
Similarly for __cxa_guard_release and __cxa_guard_abort


Repository:
  rCXXA libc++abi

https://reviews.llvm.org/D85873

Files:
  libcxxabi/include/cxxabi.h


Index: libcxxabi/include/cxxabi.h
===================================================================
--- libcxxabi/include/cxxabi.h
+++ libcxxabi/include/cxxabi.h
@@ -21,6 +21,7 @@
 
 #define _LIBCPPABI_VERSION 1002
 #define _LIBCXXABI_NORETURN  __attribute__((noreturn))
+#define _LIBCXXABI_ALWAYS_COLD __attribute__((cold))
 
 #ifdef __cplusplus
 
@@ -78,13 +79,13 @@
 
 // 3.3.2 One-time Construction API
 #if defined(_LIBCXXABI_GUARD_ABI_ARM)
-extern _LIBCXXABI_FUNC_VIS int __cxa_guard_acquire(uint32_t *);
-extern _LIBCXXABI_FUNC_VIS void __cxa_guard_release(uint32_t *);
-extern _LIBCXXABI_FUNC_VIS void __cxa_guard_abort(uint32_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD int __cxa_guard_acquire(uint32_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_release(uint32_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_abort(uint32_t *);
 #else
-extern _LIBCXXABI_FUNC_VIS int __cxa_guard_acquire(uint64_t *);
-extern _LIBCXXABI_FUNC_VIS void __cxa_guard_release(uint64_t *);
-extern _LIBCXXABI_FUNC_VIS void __cxa_guard_abort(uint64_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD int __cxa_guard_acquire(uint64_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_release(uint64_t *);
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_abort(uint64_t *);
 #endif
 
 // 3.3.3 Array Construction and Destruction API


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