aCC generates backtrace when using va_list.

[Eugene Gruber]

I'm porting a large library from gcc 2.95.2 on Solaris to aCC on HP-UX. I have one module from the hundreds I've compiled for which the compiler generates a call stack trace.

The swlist command on our HP-UX 11.0 system shows:

PHSS_24627 1.0 HP aC++ -AA runtime libraries (aCC A.03.33)
PHSS_25170 1.0 HP aC++ Compiler (aCC A.03.31)

The problem appears to be related to va_list.
When compiling the module I'm porting, the
compiler reported a system error. When
compiling a simple sample to demonstrate the
problem, the compiler generated an internal
error.

It should be noted that the internal error was
generated by both
aCC -Ae -c GGtest.c
and
aCC -c GGtest.c

Included below are my simple sample program,
the call stack from the attempted compilation
of that, and the call stack from the module
I'm porting.

Any suggestions of work-arounds, or
observation of error on my part, are greatly
appreciated.

/* GGtest.c.
*
* Try out varargs and see if it will compile with aCC -Ae.
*/
#include

int main (int argc, char** argv)
{
va_list ap;
char *fmt = argv[1];

va_start(ap, fmt);
va_end(ap);
return 0;
}

Here's the call stack from the compile of my
sample program:

( 0) 0x002adcf8 toolError__12ErrorHandlerF11StringTokenRC8Positione + 0x58 [/opt/aCC/lbin/ctcom.pa20]
( 1) 0x00339f54 fe_error + 0x204 [/opt/aCC/lbin/ctcom.pa20]
( 2) 0x008591f8 print_undef + 0x24 [/opt/aCC/lbin/ctcom.pa20]
( 3) 0x0025ef14 scan_symbols + 0x170 [/opt/aCC/lbin/ctcom.pa20]
( 4) 0x00138218 pass1_sllic + 0x34 [/opt/aCC/lbin/ctcom.pa20]
( 5) 0x001448e4 process_sllic_graph + 0xac
[/opt/aCC/lbin/ctcom.pa20]
( 6) 0x00119064 finish_program + 0x94 [/opt/aCC/lbin/ctcom.pa20]
( 7) 0x0010c348 cg_stp + 0xe4 [/opt/aCC/lbin/ctcom.pa20]
( 8) 0x0035c124 be_stp + 0x1c [/opt/aCC/lbin/ctcom.pa20]
( 9) 0x002903e8 ucodeCodeGenTerm__Fv + 0x70 [/opt/aCC/lbin/ctcom.pa20]
(10) 0x00282f60 main + 0x6a8 [/opt/aCC/lbin/ctcom.pa20]
(11) 0xc013e604 _start + 0xc8 [/usr/lib/libc.2]
(12) 0x0010d930 $START$ + 0x1a0 [/opt/aCC/lbin/ctcom.pa20]
Error (internal problem) 7403: Exact position unknown; near
["/usr/include/varargs.h", line 85].
# undefined label - (7403)


The call stack from the compile of the module I'm porting showed a more severe error:

Signal 11
( 0) 0x002a2530 sighandler__FiT1 + 0x148 [/opt/aCC/lbin/ctcom.pa20]
( 1) 0xc01f2de8 _sigreturn [/usr/lib/libc.2]
( 2) 0x001ea744 doReduction3__FiR12ScannerValueP12ScannerValue + 0xb934 [/opt/aCC/lbin/ctcom.pa20]
( 3) 0x001ec7fc yyparse__Fv + 0xc28 [/opt/aCC/lbin/ctcom.pa20]
( 4) 0x00275698 DoCompile__8CompilerFv + 0x20c [/opt/aCC/lbin/ctcom.pa20]
( 5) 0x0010e5ec DoCompile__8CompilerFP6Buffer + 0x34 [/opt/aCC/lbin/ctcom.pa20]
( 6) 0x00118110 DoCompileFile__8CompilerFPc + 0x25c [/opt/aCC/lbin/ctcom.pa20]
( 7) 0x00282ef4 main + 0x63c [/opt/aCC/lbin/ctcom.pa20]
( 8) 0xc013e604 _start + 0xc8 [/usr/lib/libc.2]
( 9) 0x0010d930 $START$ + 0x1a0 [/opt/aCC/lbin/ctcom.pa20]
Error (system problem) 689:
# Compiler received signal 11

[Gregory Fruth]

Perhaps this is specific to your cut-down example,
but I don't think it makes any sense to use va_start(),
va_end(), etc. inside a function with a fixed
argument list such as main(). AFAIK the behavior
is undefined and mayhem will ensue. However, I
do agree that the compiler shouldn't biff on it. gcc,
for example, warns you:

myprog.c: In function `main':
myprog.c:8: `va_start' used in function with fixed args

HP's C compiler doesn't complain, but it doesn't
crash on it either.

If you're trying to process the command line
arguments you can just iterate through argv[]
from 1 through argc-1. Otherwise, perhaps
you could provide an example which has
a variable argument list.

[Eugene Gruber]

Thanks, Gregory.

I took your advice, and built a new cut-down sample. Unfortunately for me, this sample works. So now I have to go back to the module I'm porting and see if I can find anything else there that looks suspicious, that could be causing the:

Error (system problem) 689:
# Compiler received signal 11

[T. M. Louah]

aCC release information can be found here:
http://h21007.www2.hp.com/dspp/tech/tech_TechSoftwareDetailPage_IDX/1,1703,1743,00.html