[gcc] Eliminate control integrity pass in favor of nacl instructions generation from the start.

gcc/gcc/config/i386/i386.c

Index: gcc/gcc/config/i386/i386.c
diff --git a/gcc/gcc/config/i386/i386.c b/gcc/gcc/config/i386/i386.c
index 42c2dbfe995581075a9f038f3ec4c31bad087673..24a9cf0e5614205f39b507d335484f697da90f61 100644
--- a/gcc/gcc/config/i386/i386.c
+++ b/gcc/gcc/config/i386/i386.c
@@ -19111,7 +19111,13 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
       fnaddr = gen_rtx_MEM (QImode, fnaddr);
     }
 
-  call = gen_rtx_CALL (VOIDmode, fnaddr, callarg1);
+  if (!TARGET_NACL
+      || (GET_CODE (fnaddr) == MEM
+          && constant_call_address_operand (XEXP (fnaddr, 0), Pmode)))
+    call = gen_rtx_CALL (VOIDmode, fnaddr, callarg1);
+  else
+    call = gen_rtx_UNSPEC (VOIDmode, gen_rtvec (2, fnaddr, callarg1),

[pasko-google - do not use, 2010/06/21 21:42:11]

did you investigate the possibility to make a (call (unspec ...))

this way we would be able to say things like "this insn is a call" and some
rules can be applied to that (say, register save/restore, or PIC?). Though it's
the backend where this information is probably already have been used. Not sure.


Please, also run the GCC testsuite with this change.

[eaeltsin, 2010/06/22 04:04:55]

I generate rtl that is matchable with naclcall define_insns. Their patterns are
unspec _instead_of_ call.

At some point it may be worth trying what you suggest, but this will require
changing all naclcall define_insns rtl patterns.
This is still a CALL_INSN, so the stuff you mention applies.

However, making its rtl to have a CALL expression may help gcc to optimize. It
is worth investigating, but as the performance didn't regress with this change,
it is of low priority.

+                           UNSPEC_NACLCALL);
   if (retval)
     call = gen_rtx_SET (VOIDmode, retval, call);
   if (pop)