Call tls_get_addr via GOT for GNU TLS if possible

Programming / Compilers / GCC - hjl [138bc75d-0d04-0410-961f-82ee72b054a4] - 24 June 2016 12:32 UTC

There are extensions to x86-64 psABI:

https://groups.google.com/forum/#!topic/x86-64-abi/de5_KnLHxtI

and i386 psABI:

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

to call tls_get_addr via GOT. X86 assembler and linker in binutils 2.27 implemented

call *__tls_get_addr@GOTPCREL(%rip)

in 64-bit and

call *___tls_get_addr@GOT(%reg)

in 32-bit to access global and local thread loal variables in shared library. We check if 32-bit x86 assembler and linker work with

call *___tls_get_addr@GOT(%reg)

as 32-bit and 64-bit assembler and linker are enabled togther.

In 32-bit, since any integer register except EAX, which is used to pass parameter to ___tls_get_addr, and ESP, can be used as GOT base, a new register class, TLS_GOTBASE_REGS, along with a new constraint, Yb, are added. They are used to improve register allocation for 32-bit dynamic TLS patterns.

gcc/

- configure.ac (calling ___tls_get_addr via GOT): New assembler/linker check. (HAVE_AS_IX86_TLS_GET_ADDR_GOT): New. Defined to 1 if 32-bit assembler and linker supports calling ___tls_get_addr via GOT. Otherise, defined to 0.
- config.in: Regenerated.
- configure: Likewise.
- config/i386/constraints.md (Yb): New constraint.
- config/i386/i386.h (reg_class): Add TLS_GOTBASE_REGS. (REG_CLASS_NAMES): Likewise. (REG_CLASS_CONTENTS): Likewise.
- config/i386/i386.md (*tls_global_dynamic_32_gnu): Replace the b constraint with the Yb constraint. Call ___tls_get_addr
via GOT for GNU TLS with -fno-plt if HAVE_AS_IX86_TLS_GET_ADDR_GOT is 1. (*tls_local_dynamic_base_32_gnu): Likewise. (*tls_global_dynamic_64_): Call _tls_get_addr via GOT for GNU TLS with -fno-plt if HAVE_AS_IX86_TLS_GET_ADDR_GOT is 1. (*tls_local_dynamic_base_64_): Likewise.

gcc/testsuite/

- gcc.target/i386/noplt-gd-1.c: New test.
- gcc.target/i386/noplt-gd-2.c: Likewise.
- gcc.target/i386/noplt-gd-3.c: Likewise.
- gcc.target/i386/noplt-ld-1.c: Likewise.
- gcc.target/i386/noplt-ld-2.c: Likewise.
- gcc.target/i386/noplt-ld-3.c: Likewise.
- lib/target-supports.exp (check_effective_target_tls_get_addr_via_got): New.

c7f16cf Call tls_get_addr via GOT for GNU TLS if possible
gcc/config.in | 7 ++++
gcc/config/i386/constraints.md | 11 ++++++
gcc/config/i386/i386.h | 3 ++
gcc/config/i386/i386.md | 33 ++++++++++++-----
gcc/configure | 53 ++++++++++++++++++++++++++++
gcc/configure.ac | 30 ++++++++++++++++
gcc/testsuite/gcc.target/i386/noplt-gd-1.c | 27 ++++++++++++++
gcc/testsuite/gcc.target/i386/noplt-gd-2.c | 28 +++++++++++++++
gcc/testsuite/gcc.target/i386/noplt-gd-3.c | 12 +++++++
gcc/testsuite/gcc.target/i386/noplt-ld-1.c | 27 ++++++++++++++
gcc/testsuite/gcc.target/i386/noplt-ld-2.c | 21 +++++++++++
gcc/testsuite/gcc.target/i386/noplt-ld-3.c | 12 +++++++
gcc/testsuite/lib/target-supports.exp | 51 ++++++++++++++++++++++++++
13 files changed, 306 insertions(+), 9 deletions(-)

Upstream: gcc.gnu.org

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