Interpreter does not support the vaarg instruction

[llvmbot]

Bugzilla Link	99
Resolution	FIXED
Resolved on	Feb 22, 2010 12:45
Version	trunk
OS	All
Reporter	LLVM Bugzilla Contributor
CC	@lattner

Extended Description

%tmp.10 = vaarg sbyte* %ap.0, sbyte* ; <sbyte*> [#uses=1]
lli: Interpreter.h:135: void Interpreter::visitInstruction(Instruction&):
Assertion `0 && "Instruction not interpretable yet!"' failed.

The interpreter should support the 'vaarg' instruction, and it currently does
not. I get the above assertion failure when testing 2003-05-07-VarArgs with lli.

[llvmbot]

2003-05-07-VarArgs and many other vaarg tests work now, but 2003-08-11-VaListArg
still crashes.

[llvmbot]

narrowed it down to:

#include <stdio.h>
#include <stdarg.h>

void test(char *fmt, va_list ap) {
char *s;
switch(*fmt++) {
case 's':
s = va_arg(ap, char *);
printf("string %s\n", s);
break;
}
va_end(ap);
}

void testVaListArg(char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
test(fmt, ap);
va_end(ap);
}

int main() {
testVaListArg("s", "abc");
return 0;
}

[llvmbot]

This may be fixable by representing a va_list as a pair
{ ExecutionContext *, int }
or (better?)
as an iterator into the std::vector that we use
to store varargs, instead of just an int.

[llvmbot]

This bug is now fixed. The interpreter now does no worse than any other backend
on the SingleSource/UnitTests!

http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20031110/009480.html