Add -mfunction-return= option to convert function return to call and
return thunks. The default is 'keep', which keeps function return
unmodified. 'thunk' converts function return to call and return thunk.
'thunk-inline' converts function return to inlined call and return thunk.
'thunk-extern' converts function return to external call and return
thunk provided in a separate object file. You can control this behavior
for a specific function by using the function attribute function_return.
Function return thunk is the same as memory thunk for -mindirect-branch=
where the return address is at the top of the stack:
__x86_return_thunk:
call L2
L1:
pause
lfence
jmp L1
L2:
lea 8(%rsp), %rsp|lea 4(%esp), %esp
ret
and function return becomes
jmp __x86_return_thunk
-mindirect-branch= tests are updated with -mfunction-return=keep to
avoid false test failures when -mfunction-return=thunk is added to
RUNTESTFLAGS for "make check".
gcc/
Backport from mainline
2018-01-14 H.J. Lu <hongjiu.lu@intel.com>
* config/i386/i386-protos.h (ix86_output_function_return): New.
* config/i386/i386.c (ix86_set_indirect_branch_type): Also
set function_return_type.
(indirect_thunk_name): Add ret_p to indicate thunk for function
return.
(output_indirect_thunk_function): Pass false to
indirect_thunk_name.
(ix86_output_indirect_branch_via_reg): Likewise.
(ix86_output_indirect_branch_via_push): Likewise.
(output_indirect_thunk_function): Create alias for function
return thunk if regno < 0.
(ix86_output_function_return): New function.
(ix86_handle_fndecl_attribute): Handle function_return.
(ix86_attribute_table): Add function_return.
* config/i386/i386.h (machine_function): Add
function_return_type.
* config/i386/i386.md (simple_return_internal): Use
ix86_output_function_return.
(simple_return_internal_long): Likewise.
* config/i386/i386.opt (mfunction-return=): New option.
(indirect_branch): Mention -mfunction-return=.
* doc/extend.texi: Document function_return function attribute.
* doc/invoke.texi: Document -mfunction-return= option.
gcc/testsuite/
Backport from mainline
2018-01-14 H.J. Lu <hongjiu.lu@intel.com>
* gcc.target/i386/indirect-thunk-1.c (dg-options): Add
-mfunction-return=keep.
* gcc.target/i386/indirect-thunk-2.c: Likewise.
* gcc.target/i386/indirect-thunk-3.c: Likewise.
* gcc.target/i386/indirect-thunk-4.c: Likewise.
* gcc.target/i386/indirect-thunk-5.c: Likewise.
* gcc.target/i386/indirect-thunk-6.c: Likewise.
* gcc.target/i386/indirect-thunk-7.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-1.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-2.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-3.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-4.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-5.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-6.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-7.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-8.c: Likewise.
* gcc.target/i386/indirect-thunk-bnd-1.c: Likewise.
* gcc.target/i386/indirect-thunk-bnd-2.c: Likewise.
* gcc.target/i386/indirect-thunk-bnd-3.c: Likewise.
* gcc.target/i386/indirect-thunk-bnd-4.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-1.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-2.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-3.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-4.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-5.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-6.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-7.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-1.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-2.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-3.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-4.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-5.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-6.c: Likewise.
* gcc.target/i386/indirect-thunk-inline-7.c: Likewise.
* gcc.target/i386/ret-thunk-1.c: New test.
* gcc.target/i386/ret-thunk-10.c: Likewise.
* gcc.target/i386/ret-thunk-11.c: Likewise.
* gcc.target/i386/ret-thunk-12.c: Likewise.
* gcc.target/i386/ret-thunk-13.c: Likewise.
* gcc.target/i386/ret-thunk-14.c: Likewise.
* gcc.target/i386/ret-thunk-15.c: Likewise.
* gcc.target/i386/ret-thunk-16.c: Likewise.
* gcc.target/i386/ret-thunk-2.c: Likewise.
* gcc.target/i386/ret-thunk-3.c: Likewise.
* gcc.target/i386/ret-thunk-4.c: Likewise.
* gcc.target/i386/ret-thunk-5.c: Likewise.
* gcc.target/i386/ret-thunk-6.c: Likewise.
* gcc.target/i386/ret-thunk-7.c: Likewise.
* gcc.target/i386/ret-thunk-8.c: Likewise.
* gcc.target/i386/ret-thunk-9.c: Likewise.
i386: Don't use ASM_OUTPUT_DEF for TARGET_MACHO
ASM_OUTPUT_DEF isn't defined for TARGET_MACHO. Use ASM_OUTPUT_LABEL to
generate the __x86_return_thunk label, instead of the set directive.
Update testcase to remove the __x86_return_thunk label check. Since
-fno-pic is ignored on Darwin, update testcases to sscan or "push"
only on Linux.
gcc/
Backport from mainline
2018-01-15 H.J. Lu <hongjiu.lu@intel.com>
PR target/83839
* config/i386/i386.c (output_indirect_thunk_function): Use
ASM_OUTPUT_LABEL, instead of ASM_OUTPUT_DEF, for TARGET_MACHO
for __x86.return_thunk.
gcc/testsuite/
Backport from mainline
2018-01-15 H.J. Lu <hongjiu.lu@intel.com>
PR target/83839
* gcc.target/i386/indirect-thunk-1.c: Scan for "push" only on
Linux.
* gcc.target/i386/indirect-thunk-2.c: Likewise.
* gcc.target/i386/indirect-thunk-3.c: Likewise.
* gcc.target/i386/indirect-thunk-4.c: Likewise.
* gcc.target/i386/indirect-thunk-7.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-1.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-2.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-5.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-6.c: Likewise.
* gcc.target/i386/indirect-thunk-attr-7.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-1.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-2.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-3.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-4.c: Likewise.
* gcc.target/i386/indirect-thunk-extern-7.c: Likewise.
* gcc.target/i386/indirect-thunk-register-1.c: Likewise.
* gcc.target/i386/indirect-thunk-register-3.c: Likewise.
* gcc.target/i386/indirect-thunk-register-4.c: Likewise.
* gcc.target/i386/ret-thunk-10.c: Likewise.
* gcc.target/i386/ret-thunk-11.c: Likewise.
* gcc.target/i386/ret-thunk-12.c: Likewise.
* gcc.target/i386/ret-thunk-13.c: Likewise.
* gcc.target/i386/ret-thunk-14.c: Likewise.
* gcc.target/i386/ret-thunk-15.c: Likewise.
* gcc.target/i386/ret-thunk-9.c: Don't check the
__x86_return_thunk label.
Scan for "push" only for Linux.
From-SVN: r256734
This directory contains the GNU Compiler Collection (GCC).
The GNU Compiler Collection is free software. See the files whose
names start with COPYING for copying permission. The manuals, and
some of the runtime libraries, are under different terms; see the
individual source files for details.
The directory INSTALL contains copies of the installation information
as HTML and plain text. The source of this information is
gcc/doc/install.texi. The installation information includes details
of what is included in the GCC sources and what files GCC installs.
See the file gcc/doc/gcc.texi (together with other files that it
includes) for usage and porting information. An online readable
version of the manual is in the files gcc/doc/gcc.info*.
See http://gcc.gnu.org/bugs/ for how to report bugs usefully.
Copyright years on GCC source files may be listed using range
notation, e.g., 1987-2012, indicating that every year in the range,
inclusive, is a copyrightable year that could otherwise be listed
individually.
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