[Gm2] gm2 segfault

[Dmitry Shatrov]

The following program causes a segmentation fault (I do "gm2 -c
test.mod")


MODULE test;

VAR A : CARDINAL;

CONST B = A;

END test.


I've tested it with the current gm2 from CVS, gm2 from gcc-4.1.2
+gm2-20070818.tar.gz tarball, and "-D 20060623" CVS branch with
gcc-3.3.6. All these combinations fail in the same way.

Here's a backtrace for current gm2 from CVS:

(gdb) bt
#0  internal_error_function (msgid=0xb7b67d51 "%s", ap=0xbfc01e10)
    at ../../gcc/gm2/gccgm2.c:2130
#1  0x08169011 in diagnostic_report_diagnostic (context=0x94a97c0, 
    diagnostic=0xbfc01df0) at ../../gcc/diagnostic.c:192
#2  0x08169212 in internal_error (gmsgid=0x848066c "%s")
    at ../../gcc/diagnostic.c:548
#3  0x08316ff4 in crash_signal (signo=11) at ../../gcc/toplev.c:587
#4  <signal handler called>
#5  0x0804e31f in constant_expression_warning (value=0x0)
    at ../../gcc/gm2/gccgm2.c:3320
#6  0x0805337c in gccgm2_DeclareKnownConstant (type=0xb7a4c958,
value=0x0)
    at ../../gcc/gm2/gccgm2.c:6095
#7  0x080a079e in CheckConstant (des=270, expr=269)
    at gm2/gm2-compiler-boot/M2GenGCC.c:1904
#8  0x080a190d in CodeBecomes (quad=7, op1=270, op2=0, op3=269)
    at gm2/gm2-compiler-boot/M2GenGCC.c:2438
#9  0x0809e4dd in CodeStatement (q=7) at
gm2/gm2-compiler-boot/M2GenGCC.c:741
#10 0x0809e236 in M2GenGCC_ConvertQuadsToTree (Start=7, End=10)
    at gm2/gm2-compiler-boot/M2GenGCC.c:655
#11 0x080bae65 in M2Scope_ForeachScopeBlockDo (sb_=0x95c5168, 
    p=0x809e225 <M2GenGCC_ConvertQuadsToTree>)
    at gm2/gm2-compiler-boot/M2Scope.c:316
#12 0x0809e1b2 in M2Code_CodeBlock (scope=85)
---Type <return> to continue, or q <return> to quit---
    at gm2/gm2-compiler-boot/M2Code.c:578
#13 0x0809d9c7 in M2Code_Code () at gm2/gm2-compiler-boot/M2Code.c:298
#14 0x0807e6eb in M2Comp_Compile (s_=0x95b6a50)
    at gm2/gm2-compiler-boot/M2Comp.c:225
#15 0x08069fe9 in StartParsing () at gm2/gm2-compiler-boot/gm2.c:132
#16 0x0806a012 in _M2_gm2_init (argc=15, argv=0xbfc02424)
    at gm2/gm2-compiler-boot/gm2.c:140
#17 0x08067fc8 in gccgm2front (argc=15, argv=0xbfc02424)
    at gm2/gm2-compiler-boot/mod_init.c:127
#18 0x0804c437 in gm2_parse_file (debug_flag=0)
at ../../gcc/gm2/gccgm2.c:2198
#19 0x0831846d in toplev_main (argc=15, argv=0xbfc02424)
    at ../../gcc/toplev.c:991
#20 0x080f51b2 in main (argc=Cannot access memory at address 0x0
) at ../../gcc/main.c:35