[LLVMdev] problem with lli (llvm 1.3)

[Shukang Zhou]

Hi,

I am working with llvm 1.3 on a sparcv9 machine. I have successfully built
llvm and llvm-gcc frontend. I can run many tools including llvmgcc,
llvm-dis, and llc. After using /opt/SUNWspro/bin/cc to assemble .s file
into a program binary, I can run the binary correctly as well.

I am interested in the JIT compiler (lli). When I directly run the
LLVM bytecode using interpretation ("lli -force-interpreter=true test.bc),
it works fine. But if I use the JIT compiler ("lli
-force-interpreter=false test.bc"), I got a Segmentation Fault error,
even for a small program like helloworld.

If running with gdb, the error looks like

---------------------
(gdb) r test2.bc
Starting program: /a/athena/uf24/zhou/research/llvm/src/tools/Debug/lli
test2.bc

Program received signal SIGSEGV, Segmentation fault.
0xff18505c in _doprnt () from /usr/lib/libc.so.1
(gdb) bt
#0  0xff18505c in _doprnt () from /usr/lib/libc.so.1
#1  0xff1885fc in printf () from /usr/lib/libc.so.1
#2  0xfe07ffe4 in ?? ()
#3  0xfe07ffe4 in ?? ()
Previous frame identical to this frame (corrupt stack?)
---------------------

I think the error comes because there is a system call (printf) in the
test program. I wrote another small program which explicitly uses
three system calls (fopen, fwrite, and fclose). And I also got a
segmentation fault, as:

----------------------
(gdb) r test3.bc
Starting program: /a/athena/uf24/zhou/research/llvm/src/tools/Debug/lli
test3.bc

Program received signal SIGSEGV, Segmentation fault.
0xff370730 in memcpy () from
/usr/platform/SUNW,Sun-Fire-280R/lib/libc_psr.so.1
(gdb) bt
#0  0xff370730 in memcpy ()
   from /usr/platform/SUNW,Sun-Fire-280R/lib/libc_psr.so.1
#1  0xfe07ffe4 in ?? ()
#2  0xfe07ffe4 in ?? ()
Previous frame identical to this frame (corrupt stack?)
----------------------

However, if the program doesn't do anything (i.e., an empty main()
function). The lli won't crash.

I traced lli using gdb, and found that it crashes within
JIT::runFunction(). In particular, the problem is in line 70 of JIT.cpp:

    int ExitCode = PF(ArgValues[0].IntVal, (char **) GVTOP (ArgValues[1]),
                      (const char **) GVTOP (ArgValues[2]));

Is anybody having any idea about this? Thanks a lot.


Shukang Zhou