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
c03a554103