AArch64 TLSDESC for local symbol in shared objects are implemented in a
arch specific manner where the TLSDESC dynamic relocation addend is the
symbol VM inside the TLS block. For instance, with a shared library
created from the code:
--
static __thread int32_t x1;
static __thread int64_t x2;
int32_t foo1 (int32_t x)
{
x1 += x;
return x;
}
int64_t foo2 (int64_t x)
{
x2 += x;
return x;
}
--
The dynamic relocation should be create as:
Relocations [
Section (N) .rela.dyn {
<Address1> R_AARCH64_TLSDESC - 0x0
<Address2> R_AARCH64_TLSDESC - 0x8
}
]
Where 0x0 addend in first dynamic relocation is the address of 'x1'
in TLS block and '0x8' is the address of 'x2'.
Checked against test-suite on aarch64-linux-gnu.
llvm-svn: 290099
This is mostly extracted from http://reviews.llvm.org/D18960.
The general idea for tlsdesc is that the two GD got entries are used
for a function pointer and its argument. The dynamic linker sets
both. In the non-dlopen case the dynamic linker sets the function to
the identity and the argument to the offset in the tls block.
All that the static linker has to do in the non-dlopen case is
relocate the code to point to the got entries and create a dynamic
relocation.
The dlopen case is more complicated, but can be implemented in another patch.
llvm-svn: 271569
Adhemerval Zanella