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[sanitizer] Extract SANITIZER_FREEBSD version of ThreadDescriptorSizeFallback #109743

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Merged
merged 2 commits into from
Sep 25, 2024
Merged

[sanitizer] Extract SANITIZER_FREEBSD version of ThreadDescriptorSizeFallback #109743

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dbfb4b5
[𝘀𝗽𝗿] initial version
vitalybuka Sep 24, 2024
d4bc0b7
no redundant #if
vitalybuka Sep 25, 2024
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55 changes: 42 additions & 13 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 @@ -217,27 +217,14 @@ static void GetGLibcVersion(int *major, int *minor, int *patch) {
*minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
*patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
}
# endif // SANITIZER_GLIBC && !SANITIZER_GO

// On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
// of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
// 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 uptr thread_descriptor_size;

// FIXME: Implementation is very GLIBC specific, but it's used by FreeBSD.
static uptr ThreadDescriptorSizeFallback() {
# if defined(__x86_64__) || defined(__i386__) || defined(__arm__) || \
SANITIZER_RISCV64
# if SANITIZER_GLIBC
int major;
int minor;
int patch;
GetGLibcVersion(&major, &minor, &patch);
# else // SANITIZER_GLIBC
return 0;
# endif // SANITIZER_GLIBC
# endif

# if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
Expand Down Expand Up @@ -304,6 +291,48 @@ static uptr ThreadDescriptorSizeFallback() {
return 1776; // from glibc.ppc64le 2.20-8.fc21
# endif
}
# endif // SANITIZER_GLIBC && !SANITIZER_GO

# if SANITIZER_FREEBSD && !SANITIZER_GO
// FIXME: Implementation is very GLIBC specific, but it's used by FreeBSD.
static uptr ThreadDescriptorSizeFallback() {
# if defined(__s390__) || defined(__sparc__)
// The size of a prefix of TCB including pthread::{specific_1stblock,specific}
// suffices. Just return offsetof(struct pthread, specific_used), which hasn't
// changed since 2007-05. Technically this applies to i386/x86_64 as well but
// we call _dl_get_tls_static_info and need the precise size of struct
// pthread.
return FIRST_32_SECOND_64(524, 1552);
# endif

# if defined(__mips__)
// TODO(sagarthakur): add more values as per different glibc versions.
return FIRST_32_SECOND_64(1152, 1776);
# endif

# if SANITIZER_LOONGARCH64
return 1856; // from glibc 2.36
# endif

# if defined(__aarch64__)
// The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
return 1776;
# endif

# if defined(__powerpc64__)
return 1776; // from glibc.ppc64le 2.20-8.fc21
# endif

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I have a hard time believing that that's any point in this: apart from being glibc-specific, as of FreeBSD 14.1 there isn't a s390, sparc, mips, or loongarch64 port of FreeBSD.

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If you are confident, I can drop them in followup PR, so bisecting could be easiers.

According to https://www.freebsd.org/platforms/
Recent Tier 1 are only x86_64 and aarch64, the former works with 0.

I guess implication of having these values invalid is incorrect DTLS detection which will false positive for msan and lsan.

return 0;
}
# endif // SANITIZER_FREEBSD && !SANITIZER_GO

# if (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
// On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
// of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
// to get the pointer to thread-specific data keys in the thread control block.
// sizeof(struct pthread) from glibc.
static uptr thread_descriptor_size;

uptr ThreadDescriptorSize() { return thread_descriptor_size; }

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