[patch] Make _thread_db_sizeof_pthread public for Sanitizers

[Jan Kratochvil]

On Fri, 01 Jan 2021 13:42:43 +0100, Florian Weimer wrote:
> Do you know why the GetTLS function needs to know the size of the
> thread descriptor?  And why it adds it to the start address of the TLS
> area, without subtracting it from the area size?  I think this
> identifies the wrong memory region as TLS.

I do not know the memory layout of glibc TLSes (all of their kinds there are).

I just find my proposed fix a better one than to play the catch-up with each
glibc version. If you can find some better fix I sure welcome it.

https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp#L468
https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp#L237
=
static void GetTls(uptr *addr, uptr *size) {
#if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
  *addr = ThreadSelf();
  *size = GetTlsSize(); // get_tls_static_info_ptr()->dl_tls_static_size
  *addr -= *size;
  *addr += ThreadDescriptorSize();


Jan