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[libcxxabi] Make InitByteGlobalMutex check GetThreadID instead of PlatformThreadID 

By relying on PlatformSupportsThreadID, InitByteGlobalMutex disregards
the GetThreadID template argument, rendering it useless.

This is the 2nd of 5 changes to overhaul cxa_guard.
See D108343 for what the final result will be.

Depends on D109539

Reviewed By: ldionne, #libc_abi

Differential Revision: https://reviews.llvm.org/D110088
This commit is contained in:
Daniel McIntosh 2021-08-16 14:07:55 -04:00
parent e42eeb88d7
commit 3601ee6cfd
2 changed files with 10 additions and 9 deletions
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10
libcxxabi/src/cxa_guard_impl.h
View File

@ -156,8 +156,6 @@ uint32_t PlatformThreadID() {
constexpr uint32_t (*PlatformThreadID)() = nullptr;
#endif
constexpr bool PlatformSupportsThreadID() { return +PlatformThreadID != nullptr; }
//===----------------------------------------------------------------------===//
// GuardBase
//===----------------------------------------------------------------------===//
@ -289,7 +287,7 @@ struct InitByteGlobalMutex : GuardObject<InitByteGlobalMutex<Mutex, CondVar, glo
using BaseT::BaseT;
explicit InitByteGlobalMutex(uint32_t* g) : BaseT(g), has_thread_id_support(false) {}
explicit InitByteGlobalMutex(uint64_t* g) : BaseT(g), has_thread_id_support(PlatformSupportsThreadID()) {}
explicit InitByteGlobalMutex(uint64_t* g) : BaseT(g), has_thread_id_support(GetThreadID != nullptr) {}
public:
AcquireResult acquire_init_byte() {
@ -404,12 +402,14 @@ struct InitByteFutex : GuardObject<InitByteFutex<Wait, Wake, GetThreadIDArg>> {
/// ARM Constructor
explicit InitByteFutex(uint32_t* g)
: BaseT(g), init_byte(this->init_byte_address), has_thread_id_support(this->thread_id_address && GetThreadIDArg),
: BaseT(g), init_byte(this->init_byte_address),
has_thread_id_support(this->thread_id_address && GetThreadIDArg != nullptr),
thread_id(this->thread_id_address) {}
/// Itanium Constructor
explicit InitByteFutex(uint64_t* g)
: BaseT(g), init_byte(this->init_byte_address), has_thread_id_support(this->thread_id_address && GetThreadIDArg),
: BaseT(g), init_byte(this->init_byte_address),
has_thread_id_support(this->thread_id_address && GetThreadIDArg != nullptr),
thread_id(this->thread_id_address) {}
public:

9
libcxxabi/test/guard_test_basic.pass.cpp
View File

@ -12,9 +12,10 @@
#include "../src/cxa_guard_impl.h"
#include <cassert>
// Disable GCC warning about tautological comparison of a function's address
#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic ignored "-Waddress"
#if defined(__clang__)
# pragma clang diagnostic ignored "-Wtautological-pointer-compare"
#elif defined(__GNUC__)
# pragma GCC diagnostic ignored "-Waddress"
#endif
using namespace __cxxabiv1;
@ -135,7 +136,7 @@ int main(int, char**) {
#if (defined(__APPLE__) || defined(__linux__)) && !defined(_LIBCXXABI_HAS_NO_THREADS)
assert(PlatformThreadID);
#endif
if (PlatformSupportsThreadID()) {
if (PlatformThreadID != nullptr) {
assert(PlatformThreadID() != 0);
assert(PlatformThreadID() == PlatformThreadID());
}