Hi, this is a regression present for x86-64 on mainline and 4.6 branch with the options -Os -mpreferred-stack-boundary=5 -fstack-check -fno-omit-frame-pointer. This improbable combination of options is necessary because you need to have stack checking + stack realignment + !ACCUMULATE_OUTGOING_ARGS. In this case, the DW_CFA_GNU_args_size CFIs must be correct in spite of the frame pointer.
Tested on {i586,x86_64}-suse-linux, OK for mainline and 4.6 branch? 2011-03-30 Eric Botcazou <ebotca...@adacore.com> PR target/48142 * config/i386/i386.c (ix86_adjust_stack_and_probe): Differentiate frame-related from frame-unrelated adjustments to the stack pointer. 2011-03-30 Eric Botcazou <ebotca...@adacore.com> * g++.dg/other/pr48142.C: New test. -- Eric Botcazou
// PR target/48142 // Testcase by Zdenek Sojka <zso...@seznam.cz> // { dg-do run { target i?86-*-* x86_64-*-* } } // { dg-options "-Os -mpreferred-stack-boundary=5 -fstack-check -fno-omit-frame-pointer" } int main() { try { throw 0; } catch (...) {} return 0; }
Index: config/i386/i386.c =================================================================== --- config/i386/i386.c (revision 171716) +++ config/i386/i386.c (working copy) @@ -10006,7 +10006,7 @@ ix86_adjust_stack_and_probe (const HOST_ probe that many bytes past the specified size to maintain a protection area at the botton of the stack. */ const int dope = 4 * UNITS_PER_WORD; - rtx size_rtx = GEN_INT (size); + rtx size_rtx = GEN_INT (size), last; /* See if we have a constant small number of probes to generate. If so, that's the easy case. The run-time loop is made up of 11 insns in the @@ -10046,9 +10046,9 @@ ix86_adjust_stack_and_probe (const HOST_ emit_stack_probe (stack_pointer_rtx); /* Adjust back to account for the additional first interval. */ - emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx, - plus_constant (stack_pointer_rtx, - PROBE_INTERVAL + dope))); + last = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx, + plus_constant (stack_pointer_rtx, + PROBE_INTERVAL + dope))); } /* Otherwise, do the same as above, but in a loop. Note that we must be @@ -10109,15 +10109,33 @@ ix86_adjust_stack_and_probe (const HOST_ } /* Adjust back to account for the additional first interval. */ - emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx, - plus_constant (stack_pointer_rtx, - PROBE_INTERVAL + dope))); + last = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx, + plus_constant (stack_pointer_rtx, + PROBE_INTERVAL + dope))); release_scratch_register_on_entry (&sr); } gcc_assert (cfun->machine->fs.cfa_reg != stack_pointer_rtx); - cfun->machine->fs.sp_offset += size; + + /* Even if the stack pointer isn't the CFA register, we need to correctly + describe the adjustments made to it, in particular differentiate the + frame-related ones from the frame-unrelated ones. */ + if (size > 0) + { + rtx expr = gen_rtx_SEQUENCE (VOIDmode, rtvec_alloc (2)); + XVECEXP (expr, 0, 0) + = gen_rtx_SET (VOIDmode, stack_pointer_rtx, + plus_constant (stack_pointer_rtx, -size)); + XVECEXP (expr, 0, 1) + = gen_rtx_SET (VOIDmode, stack_pointer_rtx, + plus_constant (stack_pointer_rtx, + PROBE_INTERVAL + dope + size)); + add_reg_note (last, REG_FRAME_RELATED_EXPR, expr); + RTX_FRAME_RELATED_P (last) = 1; + + cfun->machine->fs.sp_offset += size; + } /* Make sure nothing is scheduled before we are done. */ emit_insn (gen_blockage ());