This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PING] 3 patches waiting for approval/review

On 10/10/13 18:41, Jeff Law wrote:
> On 10/10/13 04:00, Andreas Krebbel wrote:
>> On 09/10/13 21:46, Jeff Law wrote:
>>> On 08/21/13 03:21, Andreas Krebbel wrote:
>>>> [RFC] Allow functions calling mcount before prologue to be leaf functions
>>> I don't think this is necessarily correct for all targets.  ISTM the
>>> ability to consider a function calling mcount as a leaf needs to be a
>>> property of the target.
>> We have already "profile_before_prologue" as a target property. Shouldn't this be enough to decide
>> upon this? When a function calls mcount before the prologue it shouldn't matter whether the function
>> is leaf or not.
> I don't think so, I think it'd break the PA's 32 bit ABI, maybe the 64 
> bit ABI as well.  It's the caller's responsibility to build a mini stack 
> frame if the function makes any calls.  If the code in the prologue 
> expander uses "leafness" to make the decision about whether or not to 
> allocate the mini frame, then it'd do the wrong thing here.

Since it seems to be about PROFILE_HOOKS vs FUNCTION_PROFILER targets what about the following patch:

Index: gcc/final.c
*** gcc/final.c.orig    2013-10-11 18:51:53.928452672 +0200
--- gcc/final.c 2013-10-11 18:56:20.761359142 +0200
*************** leaf_function_p (void)
*** 4237,4244 ****
    rtx insn;

!   if (crtl->profile || profile_arc_flag)
      return 0;

    for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
--- 4237,4253 ----
    rtx insn;

!   /* PROFILE_HOOK emits code always after prologue.  */
!   if (crtl->profile)
      return 0;
+ #else
+   /* This is for targets using the FUNCTION_PROFILER hook.  If the
+      code is emitted before prologue the function might still be a
+      leaf function.  */
+   if (!targetm.profile_before_prologue () && crtl->profile)
+     return 0;
+ #endif

    for (insn = get_insns (); insn; insn = NEXT_INSN (insn))

I've verified with a cross that on hppa target nothing changes when using -pg.



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]