mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-12-15 04:31:49 +08:00
f0158f4416
This patch fixes a number of issues with powerpc dynamic relocations. 1) Both ppc and ppc64 were emitting more dynamic symbols and relocations than necessary, due to not supporting static linker resolution of tls_index entries for __tls_get_addr_opt. This meant that any @got@tlsgd or @got@tlsld reloc needed to make their symbols dynamic and generate dptmod and dtprel relocs for the dynamic linker. That would have been passable, but what happened was that practically all @got relocations resulted in their symbols being made dynamic and dynamic relocations emitted against the GOT entries. (Mostly visible on ppc32 executables since ppc64 gcc really only uses @got style relocs for TLS.) 2) The PowerOpen syntax was not supported with __tls_get_addr_opt. DTPMOD/DTPREL relocs on tls_index TOC entries did not use the trick of forcing dynamic symbols and relocations so those entries always resulted in the full __tls_get_addr processing. gcc doesn't use the PowerOpen syntax for TLS, and normally such code would be optimized to TLS IE or LE so the impact of missing this support was minimal. 3) In an executable, relocations against GNU indirect functions always used the value of their PLT stub. While this is correct, it is better in some cases to use a dynamic relocation. An extra dynamic relocation can mean that calls via function pointers need not bounce through the PLT stub at runtime. The patch also tidies the PLT handling code in ppc32 allocate_dynrelocs. Allocating PLT entries after other dynamic relocs allows the PLT loop to omit special handling for undefined weak symbols, and that in turn allows the loop to be simplified. bfd/ * elf32-ppc.c (ppc_elf_adjust_dynamic_symbol): Merge two cases where dynamic relocs are preferable. Allow ifunc too. (ensure_undefweak_dynamic): New function. (allocate_dynrelocs): Use it here. Move plt handling last and don't make symbols dynamic, simplifying loop. Only make undef weak symbols with GOT entries dynamic. Correct condition for GOT relocs. Handle dynamic relocs on ifuncs. Correct comments. Remove goto. (ppc_elf_relocate_section): Correct test for using dynamic symbol on GOT relocs. Rearrange test for emitting GOT relocs to suit. Set up explicit tls_index entries and implicit GOT tls_index entries resolvable at link time for __tls_get_addr_opt. Simplify test to clear mem for prelink. * elf64-ppc.c (allocate_got): Correct condition for GOT relocs. (ensure_undefweak_dynamic): New function. (allocate_dynrelocs): Use it here. Only make undef weak symbols with GOT entries dynamic. Remove unnecessary test of WILL_CALL_FINISH_DYNAMIC_SYMBOL in PLT handling. (ppc64_elf_relocate_section): Correct test for using dynamic symbol on GOT relocs. Rearrange test for emitting GOT relocs to suit. Set up explicit tls_index entries and implicit GOT tls_index entries resolvable at link time for __tls_get_addr_opt. Simplify expression to clear mem for prelink. ld/ * testsuite/ld-powerpc/tlsexe.r: Update for fewer dynamic relocs and symbols. * testsuite/ld-powerpc/tlsexe.d: Likewise. * testsuite/ld-powerpc/tlsexe.g: Likewise.
13 lines
326 B
Plaintext
13 lines
326 B
Plaintext
#source: tls.s
|
|
#as: -a64
|
|
#ld: tmpdir/libtlslib.so
|
|
#objdump: -sj.got
|
|
#target: powerpc64*-*-*
|
|
|
|
.*
|
|
|
|
Contents of section \.got:
|
|
10010600 (00000000|00860110) (10018600|00000000) (ffffffff|1880ffff) (ffff8018|ffffffff) .*
|
|
.* 00000000 00000000 00000000 00000000 .*
|
|
.* 00000000 00000000 (ffffffff|5080ffff) (ffff8050|ffffffff) .*
|