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[libc++abi] Create a macro for the 32 bit guard setting on ARM platforms 

Summary:
The goal is to use a descriptive name for this feature, instead of just
using __arm__.

Reviewers: EricWF

Subscribers: javed.absar, kristof.beyls, christof, jkorous, dexonsmith, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D60520

llvm-svn: 358106
This commit is contained in:
Louis Dionne 2019-04-10 17:12:06 +00:00
parent 9e0eeba569
commit fa4b0b08ea
3 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
libcxxabi/include/__cxxabi_config.h
View File

@ -69,4 +69,8 @@
#define _LIBCXXABI_NO_CFI
#endif
#if defined(__arm__)
# define _LIBCXXABI_GUARD_ABI_ARM
#endif
#endif // ____CXXABI_CONFIG_H

2
libcxxabi/include/cxxabi.h
View File

@ -77,7 +77,7 @@ extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_pure_virtual(void);
extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_deleted_virtual(void);
// 3.3.2 One-time Construction API
#ifdef __arm__
#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 *);

20
libcxxabi/src/cxa_guard.cpp
View File

@ -35,7 +35,7 @@ enum InitializationResult {
INIT_NOT_COMPLETE,
};
#ifdef __arm__
#if defined(_LIBCXXABI_GUARD_ABI_ARM)
// A 32-bit, 4-byte-aligned static data value. The least significant 2 bits must
// be statically initialized to 0.
typedef uint32_t guard_type;
@ -44,7 +44,7 @@ typedef uint64_t guard_type;
#endif
#if !defined(_LIBCXXABI_HAS_NO_THREADS) && defined(__APPLE__) && \
!defined(__arm__)
!defined(_LIBCXXABI_GUARD_ABI_ARM)
// This is a special-case pthread dependency for Mac. We can't pull this
// out into libcxx's threading API (__threading_support) because not all
// supported Mac environments provide this function (in pthread.h). To
@ -239,7 +239,7 @@ GuardValue GuardValue::ZERO() { return GuardValue(0); }
GuardValue GuardValue::INIT_COMPLETE() {
guard_type value = {0};
#ifdef __arm__
#if defined(_LIBCXXABI_GUARD_ABI_ARM)
value |= 1;
#else
char* init_bit = (char*)&value;
@ -253,7 +253,7 @@ GuardValue GuardValue::INIT_PENDING() {
}
bool GuardValue::is_initialization_complete() const {
#ifdef __arm__
#if defined(_LIBCXXABI_GUARD_ABI_ARM)
return value & 1;
#else
const char* init_bit = (const char*)&value;
@ -271,31 +271,31 @@ lock_type GuardValue::get_lock_value() const {
// Create a guard object with the lock set to the specified value.
guard_type GuardValue::guard_value_from_lock(lock_type l) {
#if defined(__APPLE__) && !defined(__arm__)
#if defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
#if __LITTLE_ENDIAN__
return static_cast<guard_type>(l) << 32;
#else
return static_cast<guard_type>(l);
#endif
#else // defined(__APPLE__) && !defined(__arm__)
#else // defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
guard_type f = {0};
memcpy(static_cast<char*>(static_cast<void*>(&f)) + 1, &l, sizeof(lock_type));
return f;
#endif // defined(__APPLE__) && !defined(__arm__)
#endif // defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
}
lock_type GuardValue::lock_value_from_guard(guard_type g) {
#if defined(__APPLE__) && !defined(__arm__)
#if defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
#if __LITTLE_ENDIAN__
return static_cast<lock_type>(g >> 32);
#else
return static_cast<lock_type>(g);
#endif
#else // defined(__APPLE__) && !defined(__arm__)
#else // defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
uint8_t guard_bytes[sizeof(guard_type)];
memcpy(&guard_bytes, &g, sizeof(guard_type));
return guard_bytes[1] != 0;
#endif // defined(__APPLE__) && !defined(__arm__)
#endif // defined(__APPLE__) && !defined(_LIBCXXABI_GUARD_ABI_ARM)
}
} // __cxxabiv1