Re: toolchain/45837: perl is miscompiled on sparc64-current

[christos%zoulas.com@localhost (Christos Zoulas)]

The following reply was made to PR toolchain/45837; it has been noted by GNATS.

From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, toolchain-manager%netbsd.org@localhost, 
        gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Cc: 
Subject: Re: toolchain/45837: perl is miscompiled on sparc64-current
Date: Sun, 15 Jan 2012 11:20:45 -0500

 On Jan 15,  8:05am, martin%NetBSD.org@localhost (martin%NetBSD.org@localhost) 
wrote:
 -- Subject: toolchain/45837: perl is miscompiled on sparc64-current
 
 | >Number:         45837
 | >Category:       toolchain
 | >Synopsis:       perl is miscompiled on sparc64-current
 | >Confidential:   no
 | >Severity:       serious
 | >Priority:       medium
 | >Responsible:    toolchain-manager
 | >State:          open
 | >Class:          sw-bug
 | >Submitter-Id:   net
 | >Arrival-Date:   Sun Jan 15 08:05:00 +0000 2012
 | >Originator:     Martin Husemann
 | >Release:        NetBSD 5.99.59
 | >Organization:
 | The NetBSD Foundation, Inc.
 | >Environment:
 | System: NetBSD nelly.aprisoft.de 5.99.59 NetBSD 5.99.59 (NELLY.MP) #186: Fri 
Jan 13 12:43:00 CET 2012 
martin%emmas.aprisoft.de@localhost:/nelly/usr/src/sys/arch/sparc64/compile/NELLY.MP
 sparc64
 | Architecture: sparc64
 | Machine: sparc64
 | >Description:
 | 
 | When perl compiles a perl regexp and midway finds a UTF8 encoded part inside
 | the pattern it dies with a core dump due to a NULL pointer dereference.
 | 
 | The problem hits in perl regcomp.s line 4563:
 | 
 |    4560     /****************** LONG JUMP TARGET HERE***********************/
 |    4561     /* Longjmp back to here if have to switch in midstream to utf8 */
 |    4562     if (! RExC_orig_utf8) {
 |    4563         JMPENV_PUSH(jump_ret);
 |    4564         used_setjump = TRUE;
 |    4565     }
 | 
 | The macro JMPENV_PUSH is used in excepiton handling/unwinding and does
 | this:
 | 
 | #define JMPENV_PUSH(v) \
 |     STMT_START {                                                        \
 |         DEBUG_l({                                                       \
 |             int i = 0; JMPENV *p = PL_top_env;                          \
 |             while (p) { i++; p = p->je_prev; }                          \
 |             Perl_deb(aTHX_ "JUMPENV_PUSH level=%d at %s:%d\n",          \
 |                          i,  __FILE__, __LINE__);})                     \
 |         cur_env.je_prev = PL_top_env;                                   \
 |         OP_REG_TO_MEM;                                                  \
 |         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, 
SCOPE_SAVES_SIGNAL_M$
 |         OP_MEM_TO_REG;                                                  \
 |         PL_top_env = &cur_env;                                          \
 |         cur_env.je_mustcatch = FALSE;                                   \
 |         (v) = cur_env.je_ret;                                           \
 |     } STMT_END
 | 
 | 
 | Finally PerlProc_setjmp is a sigsetjmp(). Now the compiler generates this
 | code for the above invocation:
 | 
 |    0x4058f89c <Perl_re_compile+988>:    ldx  [ %i0 + 0x270 ], %g1
 |    0x4058f8a0 <Perl_re_compile+992>:    add  %fp, 0x69f, %o0
 |    0x4058f8a4 <Perl_re_compile+996>:    clr  %o1
 |    0x4058f8a8 <Perl_re_compile+1000>:   call  0x40780520 <__sigsetjmp14@plt>
 |    0x4058f8ac <Perl_re_compile+1004>:   stx  %g1, [ %fp + 0x697 ]
 |    0x4058f8b0 <Perl_re_compile+1008>:   add  %fp, 0x697, %g1
 |    0x4058f8b4 <Perl_re_compile+1012>:   st  %o0, [ %fp + 0x717 ]
 |    0x4058f8b8 <Perl_re_compile+1016>:   andcc  %o0, 0xff, %o1
 | => 0x4058f8bc <Perl_re_compile+1020>:   stx  %g1, [ %i0 + 0x270 ]
 | 
 | All fine, but after calling sigsetjmp, %i0 should be considered clobbered
 | as it is caller-saved. Still it just uses it in the marked instructions
 | and dies - because it is NULL now.
 | 
 | Am I missing something?
 
 Try sprinking volatile...
 
 christos