[sdcc-devel] [ sdcc-Bugs-1652207 ] SDCC SIGSEGV's

[SourceForge.net <no...@so...>]

Bugs item #1652207, was opened at 2007-02-05 09:06
Message generated for change (Comment added) made by bernhardheld
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=1652207&group_id=599

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Live range problems
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Weston T. Schmidt (schmidtw)
Assigned to: Bernhard Held (bernhardheld)
Summary: SDCC SIGSEGV's

Initial Comment:
I'm running a locally built version of SDCC based on revision 4608 in Subversion.  I only made very minor build related changes - no changes to any of the source code.

In the attached source code, the error happens because I added line 402 in src/util/circular.c

To reproduce the problem:
==================================================
1. untar the attached file
2. cd into src
3. type 'make'
4. see the SIGSEGV error

Command-line that the make file uses:
==================================================
sdcc --model-large --xram-size 2048 --code-size 61440 -o util/circular.rel -c util/circular.c

Output:
==================================================
[schmidtw@wes src]$ make
Compiling ... board/mcu/audio.c
Compiling ... board/mcu/mmc.c
Compiling ... board/mcu/mp3.c
Compiling ... board/mcu/pll.c
Compiling ... board/mcu/spi.c
Compiling ... board/mcu/uart.c
Compiling ... board/dac.c
Compiling ... board/debug.c
Compiling ... board/serial.c
Compiling ... board/time.c
Compiling ... util/circular.c
util/circular.c:298: warning 126: unreachable code
util/circular.c:416: warning 84: 'auto' variable '(null)' may be used before initialization
Caught signal 11: SIGSEGV
make: *** [util/circular.rel] Error 1


----------------------------------------------------------------------

>Comment By: Bernhard Held (bernhardheld)
Date: 2007-02-05 23:04

Message:
Logged In: YES 
user_id=203539
Originator: NO

I found a bug, I'll commit the fix tomorrow.
Does circular.c now work as expected?

$ svn diff SDCCBBlock.c
Index: SDCCBBlock.c
===================================================================
--- SDCCBBlock.c        (Revision 4617)
+++ SDCCBBlock.c        (Arbeitskopie)
@@ -463,7 +463,10 @@
   /* if this is true then we put it before the condition else */
   /* we put it before if, this is to reduce register pressure, */
   /* we don't have to hold  condition too long in a register  */
-  if (ebp->ech->op == IFX)
+
+  /* loop induction sometimes appends a GOTO instruction; */
+  /* never put it before an IFX */
+  if (ebp->ech->op == IFX && ic->op != GOTO)
     {
       iCode *ipoint;


----------------------------------------------------------------------

Comment By: Bernhard Held (bernhardheld)
Date: 2007-02-05 22:13

Message:
Logged In: YES 
user_id=203539
Originator: NO

Quick response: --noinduction keeps sdcc from segfaulting.
Please give me short feedback, if the code behaves as expected with
--noinduction.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=1652207&group_id=599