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[sanitizer] Switch from lazy ThreadDescriptorSize #108923

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Merged
merged 6 commits into from
Sep 18, 2024
Merged

[sanitizer] Switch from lazy ThreadDescriptorSize #108923

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166fb73
[𝘀𝗽𝗿] changes to main this commit is based on
vitalybuka Sep 17, 2024
5750354
[𝘀𝗽𝗿] initial version
vitalybuka Sep 17, 2024
f9f4559
[𝘀𝗽𝗿] changes introduced through rebase
vitalybuka Sep 17, 2024
7da3cad
rebase
vitalybuka Sep 17, 2024
3e35f76
[𝘀𝗽𝗿] changes introduced through rebase
vitalybuka Sep 18, 2024
4e08384
rebase
vitalybuka Sep 18, 2024
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30 changes: 15 additions & 15 deletions compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -224,7 +224,7 @@ static void GetGLibcVersion(int *major, int *minor, int *patch) {
// to get the pointer to thread-specific data keys in the thread control block.
# if (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
// sizeof(struct pthread) from glibc.
static atomic_uintptr_t thread_descriptor_size;
static uptr thread_descriptor_size;

// FIXME: Implementation is very GLIBC specific, but it's used by FREEBSD.
static uptr ThreadDescriptorSizeFallback() {
Expand Down Expand Up @@ -305,20 +305,7 @@ static uptr ThreadDescriptorSizeFallback() {
# endif
}

uptr ThreadDescriptorSize() {
uptr val = atomic_load_relaxed(&thread_descriptor_size);
if (val)
return val;
// _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
// glibc 2.34 and later.
if (unsigned *psizeof = static_cast<unsigned *>(
dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread")))
val = *psizeof;
if (!val)
val = ThreadDescriptorSizeFallback();
atomic_store_relaxed(&thread_descriptor_size, val);
return val;
}
uptr ThreadDescriptorSize() { return thread_descriptor_size; }

# if SANITIZER_GLIBC
__attribute__((unused)) static size_t g_tls_size;
Expand All @@ -330,6 +317,15 @@ void InitTlsSize() {
GetGLibcVersion(&major, &minor, &patch);
g_use_dlpi_tls_data = major == 2 && minor >= 25;

if (major == 2 && minor >= 34) {
// _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
// glibc 2.34 and later.
if (unsigned *psizeof = static_cast<unsigned *>(
dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread"))) {
thread_descriptor_size = *psizeof;
}
}

# if defined(__aarch64__) || defined(__x86_64__) || \
defined(__powerpc64__) || defined(__loongarch__)
auto *get_tls_static_info = (void (*)(size_t *, size_t *))dlsym(
Expand All @@ -339,7 +335,11 @@ void InitTlsSize() {
if (get_tls_static_info)
get_tls_static_info(&g_tls_size, &tls_align);
# endif

# endif // SANITIZER_GLIBC

if (!thread_descriptor_size)
thread_descriptor_size = ThreadDescriptorSizeFallback();
}

# if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 || \
Expand Down
2 changes: 2 additions & 0 deletions compiler-rt/lib/sanitizer_common/tests/sanitizer_linux_test.cpp
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Expand Up @@ -202,6 +202,8 @@ TEST(SanitizerLinux, ThreadDescriptorSize) {
void *result;
ASSERT_EQ(0, pthread_create(&tid, 0, thread_descriptor_size_test_func, 0));
ASSERT_EQ(0, pthread_join(tid, &result));
EXPECT_EQ(0u, ThreadDescriptorSize());
InitTlsSize();
EXPECT_EQ((uptr)result, ThreadDescriptorSize());
}
# endif
Expand Down
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