On Thu, May 28, 2015 at 4:54 PM, Sriraman Tallam <tmsri...@google.com> wrote: > On Thu, May 28, 2015 at 2:52 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >> On Thu, May 28, 2015 at 2:27 PM, Sriraman Tallam <tmsri...@google.com> wrote: >>> On Thu, May 28, 2015 at 2:01 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>> On Thu, May 28, 2015 at 1:54 PM, Sriraman Tallam <tmsri...@google.com> >>>> wrote: >>>>> On Thu, May 28, 2015 at 12:05 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>>>> On Thu, May 28, 2015 at 11:50 AM, Sriraman Tallam <tmsri...@google.com> >>>>>> wrote: >>>>>>> On Thu, May 28, 2015 at 11:42 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>>>>>> On Thu, May 28, 2015 at 11:34 AM, Sriraman Tallam >>>>>>>> <tmsri...@google.com> wrote: >>>>>>>>> I have attached a patch that adds the new attribute "noplt". Please >>>>>>>>> review. >>>>>>>>> >>>>>>>>> * config/i386/i386.c (avoid_plt_to_call): New function. >>>>>>>>> (ix86_output_call_insn): Generate indirect call for functions >>>>>>>>> marked with "noplt" attribute. >>>>>>>>> (attribute_spec ix86_attribute_): Define new attribute "noplt". >>>>>>>>> * doc/extend.texi: Document new attribute "noplt". >>>>>>>>> * gcc.target/i386/noplt-1.c: New testcase. >>>>>>>>> * gcc.target/i386/noplt-2.c: New testcase. >>>>>>>>> >>>>>>>> >>>>>>>> 2 comments: >>>>>>>> >>>>>>>> 1. Don't remove "%!" prefix before call/jmp. It is needed for MPX. >>>>>>>> 2. Don't you need to check >>>>>>>> >>>>>>>> && !TARGET_MACHO >>>>>>>> && !TARGET_SEH >>>>>>>> && !TARGET_PECOFF >>>>>>>> >>>>>>>> since it only works for ELF. >>>>>>> >>>>>>> Ok, I will make this change. OTOH, is it just better to piggy-back on >>>>>>> existing -fno-plt change by Alex in calls.c >>>>>>> and do this: >>>>>>> >>>>>>> Index: calls.c >>>>>>> =================================================================== >>>>>>> --- calls.c (revision 223720) >>>>>>> +++ calls.c (working copy) >>>>>>> @@ -226,9 +226,11 @@ prepare_call_address (tree fndecl_or_type, rtx fun >>>>>>> && targetm.small_register_classes_for_mode_p (FUNCTION_MODE)) >>>>>>> ? force_not_mem (memory_address (FUNCTION_MODE, funexp)) >>>>>>> : memory_address (FUNCTION_MODE, funexp)); >>>>>>> - else if (flag_pic && !flag_plt && fndecl_or_type >>>>>>> + else if (fndecl_or_type >>>>>>> && TREE_CODE (fndecl_or_type) == FUNCTION_DECL >>>>>>> - && !targetm.binds_local_p (fndecl_or_type)) >>>>>>> + && !targetm.binds_local_p (fndecl_or_type) >>>>>>> + && ((flag_pic && !flag_plt) >>>>>>> + || (lookup_attribute ("noplt", >>>>>>> DECL_ATTRIBUTES(fndecl_or_type))))) >>>>>>> { >>>>>>> funexp = force_reg (Pmode, funexp); >>>>>>> } >>>>>>> >>>>>> >>>>>> Does it work on non-PIC calls? >>>>> >>>>> You are right, it doesnt work. I have attached the patch with the >>>>> changes you mentioned. >>>>> >>>> >>>> Since direct_p is true, do wee need >>>> >>>> + if (GET_CODE (call_op) != SYMBOL_REF >>>> + || SYMBOL_REF_LOCAL_P (call_op)) >>>> + return false; >>> >>> We do need it right because for this case below, I do not want an >>> indirect call: >>> >>> __attribute__((noplt)) >>> int foo() { >>> return 0; >>> } >>> >>> int main() >>> { >>> return foo(); >>> } >>> >>> Assuming foo is not inlined, if I remove the lines you mentioned, I >>> will get an indirect call which is unnecessary. >>> >> >> I meant the "GET_CODE (call_op) != SYMBOL_REF" part isn't >> needed. > > I should have realized that :), sorry. Patch fixed. >
--- testsuite/gcc.target/i386/noplt-1.c (revision 0) +++ testsuite/gcc.target/i386/noplt-1.c (working copy) @@ -0,0 +1,13 @@ +/* { dg-do compile { target x86_64-*-* } } */ ... +/* { dg-final { scan-assembler "call\[ \t\]\\*.*foo.*@GOTPCREL\\(%rip\\)" } } */ The test will fail on Windows and Darwin. -- H.J.