prepare_call_address in calls.c is the wrong place to handle -fno-plt.
We shoudn't force function address into register and hope that load
function address via GOT and indirect call via register will be folded
into indirect call via GOT, which doesn't always happen. Also non-PIC
case can only be handled in backend. Instead, backend should expand
external function call into indirect call via GOT for -fno-plt.
This patch reverts -fno-plt in prepare_call_address and handles it in
ix86_expand_call. Other backends may need similar changes to support
-fno-plt. Alternately, we can introduce a target hook to indicate
whether an external function should be called via register for -fno-plt
so that i386 backend can disable it in prepare_call_address.
gcc/
PR target/67215
* calls.c (prepare_call_address): Don't handle -fno-plt here.
* config/i386/i386.c (ix86_expand_call): Generate indirect call
via GOT for -fno-plt. Support indirect call via GOT for x32.
* config/i386/predicates.md (sibcall_memory_operand): Allow
GOT memory operand.
442e79d...
by
hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>
Allow indirect sibcall with register arguments
Indirect sibcall with register arguments is OK when there is register
available for argument passing.
gcc/
PR target/66819
* config/i386/i386.c (ix86_function_ok_for_sibcall): Allow
indirect sibcall with register arguments if register available
for argument passing.
(init_cumulative_args): Set cfun->machine->arg_reg_available
to (cum->nregs > 0) or to true if function has a variable
argument list.
(function_arg_advance_32): Set cfun->machine->arg_reg_available
to false if cum->nregs <= 0.
* config/i386/i386.h (machine_function): Add arg_reg_available.
ddce735...
by
tmsriram <tmsriram@138bc75d-0d04-0410-961f-82ee72b054a4>
2015-06-04 Sriraman Tallam <email address hidden>
* c-family/c-common.c (noplt): New attribute.
(handle_noplt_attribute): New handler.
* calls.c (prepare_call_address): Check for noplt
attribute.
* config/i386/i386.c (ix86_expand_call): Check
for noplt attribute.
(ix86_nopic_noplt_attribute_p): New function.
(ix86_output_call_insn): Output indirect call for non-pic
no plt calls.
* doc/extend.texi (noplt): Document new attribute.
* doc/invoke.texi: Document new attribute.
* testsuite/gcc.target/i386/noplt-1.c: New test.
* testsuite/gcc.target/i386/noplt-2.c: New test.
* testsuite/gcc.target/i386/noplt-3.c: New test.
* testsuite/gcc.target/i386/noplt-4.c: New test.
This patch does two things:
* Adds new generic function attribute "noplt" that is similar in functionality
to -fno-plt except that it applies only to calls to functions that are marked
with this attribute.
* For x86_64, it makes -fno-plt(and the attribute) also work for non-PIC code by
directly generating an indirect call via a GOT entry.
fad38a0...
by
hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>
Allow indirect branch via GOT slot for x32
X32 doesn't support indirect branch via 32-bit memory slot since
indirect branch will load 64-bit address from 64-bit memory slot.
Since x32 GOT slot is 64-bit, we should allow indirect branch via GOT
slot for x32.
gcc/
PR target/66232
* config/i386/constraints.md (Bg): New constraint for GOT memory
operand.
* config/i386/i386.md (*call_got_x32): New pattern.
(*call_value_got_x32): Likewise.
* config/i386/predicates.md (GOT_memory_operand): New predicate.
045ed2e...
by
amonakov <amonakov@138bc75d-0d04-0410-961f-82ee72b054a4>
* calls.c (prepare_call_address): Transform PLT call to GOT lookup and
indirect call by forcing address into a pseudo with -fno-plt.
* common.opt (flag_plt): New option.
* doc/invoke.texi (Code Generation Options): Add -fno-plt.
([-fno-plt]): Document.
