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Differential D85873

Add cold attribute to one time construction APIs
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Authored by hiraditya on Aug 12 2020, 10:14 PM.

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mclow.lists
ldionne
jfb
yfeldblum
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Restricted Project
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rGd54f5979bb82: Add cold attribute to one time construction APIs
Summary

__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

Diff Detail

Event Timeline

hiraditya created this revision.Aug 12 2020, 10:14 PM
Herald added subscribers: libcxx-commits, dexonsmith. · View Herald TranscriptAug 12 2020, 10:14 PM
hiraditya requested review of this revision.Aug 12 2020, 10:14 PM
hiraditya mentioned this in D85628: [HotColdSplitting] Add command line options for supplying cold function names via user input..Aug 12 2020, 10:24 PM
hiraditya edited the summary of this revision. (Show Details)Aug 12 2020, 10:30 PM
ldionne accepted this revision.Aug 13 2020, 5:42 AM
This revision is now accepted and ready to land.Aug 13 2020, 5:42 AM
Closed by commit rGd54f5979bb82: Add cold attribute to one time construction APIs (authored by hiraditya). · Explain WhyAug 13 2020, 9:30 AM
This revision was automatically updated to reflect the committed changes.
hiraditya added a commit: rGd54f5979bb82: Add cold attribute to one time construction APIs.
Herald added a project: Restricted Project. · View Herald TranscriptAug 13 2020, 9:30 AM
Herald added a reviewer: Restricted Project. · View Herald Transcript
hiraditya added a comment.Aug 13 2020, 9:59 AM

FYI: libstdc++ patch sent for review: https://gcc.gnu.org/pipermail/gcc-patches/2020-August/551934.html

Revision Contents

PathSize
libcxxabi/
include/
13 lines

Diff 285405

libcxxabi/include/cxxabi.h

Show All 15 Lines
#include <stddef.h> #include <stddef.h>
#include <stdint.h> #include <stdint.h>
#include <__cxxabi_config.h> #include <__cxxabi_config.h>
#define _LIBCPPABI_VERSION 1002 #define _LIBCPPABI_VERSION 1002
#define _LIBCXXABI_NORETURN __attribute__((noreturn)) #define _LIBCXXABI_NORETURN __attribute__((noreturn))
#define _LIBCXXABI_ALWAYS_COLD __attribute__((cold))
#ifdef __cplusplus #ifdef __cplusplus
namespace std { namespace std {
#if defined(_WIN32) #if defined(_WIN32)
class _LIBCXXABI_TYPE_VIS type_info; // forward declaration class _LIBCXXABI_TYPE_VIS type_info; // forward declaration
#else #else
class type_info; // forward declaration class type_info; // forward declaration
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// 3.2.6 Pure Virtual Function API // 3.2.6 Pure Virtual Function API
extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_pure_virtual(void); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_pure_virtual(void);
// 3.2.7 Deleted Virtual Function API // 3.2.7 Deleted Virtual Function API
extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_deleted_virtual(void); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_deleted_virtual(void);
// 3.3.2 One-time Construction API // 3.3.2 One-time Construction API
#if defined(_LIBCXXABI_GUARD_ABI_ARM) #if defined(_LIBCXXABI_GUARD_ABI_ARM)
extern _LIBCXXABI_FUNC_VIS int __cxa_guard_acquire(uint32_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD int __cxa_guard_acquire(uint32_t *);
extern _LIBCXXABI_FUNC_VIS void __cxa_guard_release(uint32_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_release(uint32_t *);
extern _LIBCXXABI_FUNC_VIS void __cxa_guard_abort(uint32_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_abort(uint32_t *);
#else #else
extern _LIBCXXABI_FUNC_VIS int __cxa_guard_acquire(uint64_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD int __cxa_guard_acquire(uint64_t *);
extern _LIBCXXABI_FUNC_VIS void __cxa_guard_release(uint64_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_release(uint64_t *);
extern _LIBCXXABI_FUNC_VIS void __cxa_guard_abort(uint64_t *); extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_ALWAYS_COLD void __cxa_guard_abort(uint64_t *);
#endif #endif
// 3.3.3 Array Construction and Destruction API // 3.3.3 Array Construction and Destruction API
extern _LIBCXXABI_FUNC_VIS void * extern _LIBCXXABI_FUNC_VIS void *
__cxa_vec_new(size_t element_count, size_t element_size, size_t padding_size, __cxa_vec_new(size_t element_count, size_t element_size, size_t padding_size,
void (*constructor)(void *), void (*destructor)(void *)); void (*constructor)(void *), void (*destructor)(void *));
extern _LIBCXXABI_FUNC_VIS void * extern _LIBCXXABI_FUNC_VIS void *
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