[PATCH, ARM] Enable shrink-wrap for apcs frame

[Richard Earnshaw]

On 25/03/14 08:13, Zhenqiang Chen wrote:
> Hi
> 
> The patch enables shrink-wrap for apcs frame.
> 
> Bootstrap and no make check regression in ARM, THUMB1 and THUMB2 modes.
> No make check regression with "-g/-mapcs/-marm".
> Build linux-3.14-rc7 without error.
> 
> Is it OK for next stage1?
> 
> Thanks!
> -Zhenqiang
> 
> ChangeLog:
> 2014-03-25  Zhenqiang Chen  <zhenqiang.chen@linaro.org>
> 
>         * config/arm/arm.c (arm_option_override): Enable shrink-wrap for
>         TARGET_APCS_FRAME.
>         (arm_emit_multi_reg_pop): Set correct dwarf info.
>         (arm_expand_epilogue_apcs_frame): Add more dwarf info.
> 
> testsuite/ChangeLog:
> 2014-03-25  Zhenqiang Chen  <zhenqiang.chen@linaro.org>
> 
>         * gcc.target/arm/shrink-wrap-alloca.c: New test case.
>         * gcc.target/arm/shrink-wrap-sibcall.c: New test case.
> 
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 0240cc7..fa86942 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -2811,9 +2811,6 @@ arm_option_override (void)
>       generate additional returns.  */
>    if (optimize_function_for_size_p (cfun) && TARGET_THUMB2)
>      flag_shrink_wrap = false;
> -  /* TBD: Dwarf info for apcs frame is not handled yet.  */
> -  if (TARGET_APCS_FRAME)
> -    flag_shrink_wrap = false;
> 
>    /* We only support -mslow-flash-data on armv7-m targets.  */
>    if (target_slow_flash_data
> @@ -19840,7 +19837,14 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
>      par = emit_insn (par);
> 
>    REG_NOTES (par) = dwarf;
> -  if (!return_in_pc)
> +
> +  if (!emit_update)
> +    {
> +      /* SP is restored from stack.  So reset the frame info.  */
> +      RTX_FRAME_RELATED_P (par) = 1;
> +      add_reg_note (par, REG_CFA_DEF_CFA, stack_pointer_rtx);
> +    }
> +  else if (!return_in_pc)
>      arm_add_cfa_adjust_cfa_note (par, UNITS_PER_WORD * num_regs,
>                   stack_pointer_rtx, stack_pointer_rtx);
>  }
> @@ -27226,6 +27230,9 @@ arm_expand_epilogue_apcs_frame (bool really_return)
>        REG_NOTES (insn) = alloc_reg_note (REG_CFA_RESTORE,
>                                           gen_rtx_REG (SImode, IP_REGNUM),
>                                           NULL_RTX);
> +      arm_add_cfa_adjust_cfa_note (insn, UNITS_PER_WORD,
> +                   stack_pointer_rtx,
> +                   stack_pointer_rtx);

This can't be related to $SUBJECT, surely?  Shrink-wrapping an interrupt
routine?

If this is as I think, please resubmit that part as a separate patch.

The other changes look ok.

R.

>      }
> 
>    if (!really_return || (saved_regs_mask & (1 << PC_REGNUM)))
> diff --git a/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
> b/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
> new file mode 100644
> index 0000000..318240b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g -mapcs " } */
> +
> +int *p;
> +
> +void
> +test (int a)
> +{
> +  if (a > 0)
> +    p = __builtin_alloca (4);
> +}
> diff --git a/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
> b/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
> new file mode 100644
> index 0000000..2efe5d0
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
> @@ -0,0 +1,26 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g -mapcs " } */
> +
> +unsigned char a, b, d, f, g;
> +
> +int test (void);
> +
> +int
> +baz (int c)
> +{
> +  if (c == 0) return test ();
> +  if (b & 1)
> +    {
> +      g = 0;
> +      int e = (a & 0x0f) - (g & 0x0f);
> +
> +      if (!a)  b |= 0x80;
> +      a = e + test ();
> +     f = g/5 + a*3879 + b *2985;
> +    }
> +   else
> +   {
> +     f = g + a*39879 + b *25;
> +   }
> +  return test ();
> +}
>