gold: Support 386 TLS code sequences without PLT
authorH.J. Lu <hjl.tools@gmail.com>
Wed, 29 Jun 2016 15:38:43 +0000 (08:38 -0700)
committerH.J. Lu <hjl.tools@gmail.com>
Wed, 29 Jun 2016 15:38:58 +0000 (08:38 -0700)
commitb287eca391bbb10e709fb8ba9a56be166ab2ff1d
tree5a26635b87621c0df49ebaac6ccdcc456f92e974
parentad961eab9a010e79d17a4ea7e6bb977fe6dd86c2
gold: Support 386 TLS code sequences without PLT

There are extensions to 386 psABI:

https://groups.google.com/forum/#!topic/ia32-abi/awsRSvJOJfs

to call tls_get_addr via GOT:

call *___tls_get_addr@GOT(%reg)

where EBX register isn't required as GOT base.

Since direct call is 4-byte long and indirect call, is 5-byte long, the
extra one byte must be handled properly.

For general dynamic model, 7-byte lea instruction before call
instruction is replaced by 6-byte one to make room for indirect call.
For local dynamic model, we simply use 5-byte indirect call.

TLS linker optimization is updated to recognize new instruction
patterns.  For local dynamic model to local exec model transition,
we generate a 6-byte lea instruction as nop, instead of a 1-byte nop
plus a 4-byte lea instruction.

PR gold/20308
* i386.cc (Target_i386::Relocate::relocate): Allow
R_386_GOT32X relocation against ___tls_get_addr.
(Target_i386::Relocate::tls_gd_to_ie): Support indirect
call to __tls_get_addr.
(Target_i386::Relocate::tls_gd_to_le): Likewise.
(Target_i386::Relocate::tls_ld_to_le): Likewise.
* testsuite/Makefile.am (check_PROGRAMS): Add pr20308a_test,
pr20308b_test, pr20308c_test, pr20308d_test, pr20308e_test.
(pr20308a_test_SOURCES): New.
(pr20308a_test_DEPENDENCIES): Likewise.
(pr20308a_test_CFLAGS): Likewise.
(pr20308a_test_LDFLAGS): Likewise.
(pr20308a_test_LDADD): Likewise.
(pr20308b_test_SOURCES): Likewise.
(pr20308b_test_DEPENDENCIES): Likewise.
(pr20308b_test_CFLAGS): Likewise.
(pr20308b_test_LDFLAGS): Likewise.
(pr20308b_test_LDADD): Likewise.
(pr20308c_test_SOURCES): Likewise.
(pr20308c_test_DEPENDENCIES): Likewise.
(pr20308c_test_CFLAGS): Likewise.
(pr20308c_test_LDFLAGS): Likewise.
(pr20308c_test_LDADD): Likewise.
(pr20308d_test_SOURCES): Likewise.
(pr20308d_test_DEPENDENCIES): Likewise.
(pr20308d_test_CFLAGS): Likewise.
(pr20308d_test_LDFLAGS): Likewise.
(pr20308d_test_LDADD): Likewise.
(pr20308e_test_SOURCES): Likewise.
(pr20308e_test_DEPENDENCIES): Likewise.
(pr20308e_test_CFLAGS): Likewise.
(pr20308e_test_LDFLAGS): Likewise.
(pr20308e_test_LDADD): Likewise.
(pr20308a.so): Likewise.
(pr20308b.so): Likewise.
(pr20308_gd.o): Likewise.
(pr20308_ld.o): Likewise.
(MOSTLYCLEANFILES): Add pr20308a.so pr20308b.so.
* testsuite/Makefile.in: Regenerated.
* testsuite/pr20308_def.c: New file.
* testsuite/pr20308_gd.S: Likewise.
* testsuite/pr20308_ld.S: Likewise.
* testsuite/pr20308_main.c: Likewise.
gold/ChangeLog
gold/i386.cc
gold/testsuite/Makefile.am
gold/testsuite/Makefile.in
gold/testsuite/pr20308_def.c [new file with mode: 0644]
gold/testsuite/pr20308_gd.S [new file with mode: 0644]
gold/testsuite/pr20308_ld.S [new file with mode: 0644]
gold/testsuite/pr20308_main.c [new file with mode: 0644]