Re: [SFN+LVU+IEPM v4 9/9] [IEPM] Introduce inline entry point markers

[Alexandre Oliva <aoliva at redhat dot com>]

Hi, Joseph,

On Feb  9, 2018, Joseph Myers <joseph@codesourcery.com> wrote:

> sh4 is:

> during RTL pass: final
> In file included from strtof_l.c:45:
> strtod_l.c: In function '____strtof_l_internal':
> strtod_l.c:1769:1: internal compiler error: Segmentation fault
>  }
>  ^
> 0xb98e3f crash_signal
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/toplev.c:325
> 0x856b18 maybe_output_next_view
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:1726
> 0x856b18 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2714
> 0xef36bc print_slot
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/config/sh/sh.c:2557
> 0xef6520 output_far_jump(rtx_insn*, rtx_def*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/config/sh/sh.c:2617
> 0x857098 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:3101
> 0x856c26 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2806
> 0x858469 final_1
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2088
> 0x8591d8 rest_of_handle_final
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:4637
> 0x8591d8 execute
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:4711


> Since it's in maybe_output_next_view, I think it probably comes from these 
> patches.

Thanks for the backtraces.  The problem is that ports call
final_scan_insn recursively passing NULL for seen, but now there is code
that actually cares about carrying information around in it.  I decided
against silencing the errors by testing seen for non-NULL before
dereferencing it, and instead arranging for the outermost pointer to be
recovered in recursive calls.  I hope this is enough to cover all the
cases of final_scan_insn being called from ports.  Could you possibly
give it a spin, pretty please with sugar on top? ;-)  Thanks a ton,

(I'll provide a ChangeLog for formal review and hopefully approval once
it has gone through more than my initial smoke testing on x86_64, but my
own testing will take some time, and I wanted to give you something that
at least stood a chance of fixing the problem before crashing in bed :-)


[LVU] deal with md final_scan_insn

From: Alexandre Oliva <aoliva@redhat.com>

Ports call final_scan_insn with seen == NULL, and then
maybe_output_next_view crashes because it assumes it's
non-NULL.  Oops.  Fixed.
---
 gcc/final.c |   34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/gcc/final.c b/gcc/final.c
index c311c198da67..a60be5ddc31c 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -2236,9 +2236,9 @@ asm_show_source (const char *filename, int linenum)
    debug information.  We force the emission of a line note after
    both NOTE_INSN_PROLOGUE_END and NOTE_INSN_FUNCTION_BEG.  */
 
-rtx_insn *
-final_scan_insn (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
-		 int nopeepholes ATTRIBUTE_UNUSED, int *seen)
+static rtx_insn *
+final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
+		   int nopeepholes ATTRIBUTE_UNUSED, int *seen)
 {
 #if HAVE_cc0
   rtx set;
@@ -3204,6 +3204,34 @@ final_scan_insn (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
     }
   return NEXT_INSN (insn);
 }
+
+/* This is a wrapper around final_scan_insn_1 that allows ports to
+   call it recursively without a known value for SEEN.  The value is
+   saved at the outermost call, and recovered for recursive calls.  */
+
+rtx_insn *
+final_scan_insn (rtx_insn *insn, FILE *file, int optimize_p,
+		 int nopeepholes, int *seen)
+{
+  static int *enclosing_seen;
+  static int recursion_counter;
+
+  gcc_assert (seen || recursion_counter);
+  gcc_assert (!recursion_counter || !seen || seen == enclosing_seen);
+
+  if (!recursion_counter++)
+    enclosing_seen = seen;
+  else if (!seen)
+    seen = enclosing_seen;
+
+  rtx_insn *ret = final_scan_insn_1 (insn, file, optimize_p, nopeepholes, seen);
+  
+  if (!--recursion_counter)
+    enclosing_seen = NULL;
+
+  return ret;
+}
+
 
 /* Return whether a source line note needs to be emitted before INSN.
    Sets IS_STMT to TRUE if the line should be marked as a possible




>> (It's possible more failures might appear on other architectures once the 
>> bot builds the glibc testsuite, that's just failures from building GCC and 
>> glibc.)

> hppa has a similar ICE building glibc tests, also in 
> maybe_output_next_view, so probably also from these patches:

> during RTL pass: final
> test-tgmath2.c: In function 'test_fma_3':
> test-tgmath2.c:421:1: internal compiler error: Segmentation fault
>  }
>  ^
> 0xb7525f crash_signal
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/toplev.c:325
> 0x835f14 maybe_output_next_view
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:1726
> 0x835f14 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2714
> 0xed7761 pa_output_call(rtx_insn*, rtx_def*, int)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/config/pa/pa.c:8019
> 0x83642b final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:3101
> 0x836026 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2806
> 0x837629 final_1
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:2088
> 0x8389d6 rest_of_handle_final
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:4637
> 0x8389d6 execute
>         /scratch/jmyers/glibc-bot/src/gcc/gcc/final.c:4711

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer