llvm dev - Mar 2011 - [LLVMdev] Calling external functions failed on PowerPC

Hi, all

  I have a trouble with calling external functions on PowerPC.
What I am doing is generating a LLVM IR first like this,

- x86

 call void @helper_shack_flush(%struct.CPUX86State* %62) noinline, !flags !12

- ppc

 call void @helper_shack_flush(%struct.CPUX86State* %62) noinline, !flags !10
   
After lowering above LLVM IR for x86 and ppc, it becomes:

- x86

 %RAX<def> = MOV64ri <ga:@helper_shack_flush>
 %RDI<def> = COPY %RBX
 CALL64r %RAX<kill>, %RDI<kill>, %RAX<imp-def,dead>,
%RCX<imp-def,dead>, %RDX<imp-def,dead>, %RSI<imp-def,dead>,
%%RDI<imp-def,dead>, %R8<imp-def,dead>,
%EFLAGS<imp-def,dead>, %RSP<imp-use>, ...

- ppc

 %X4<def> = LDtoc <ga:@helper_shack_flush>, %X2

  The x86 JIT can call the external function correctly, but
the ppc JIT give me the error belows,

  %X4<def> = LDtoc <ga:@helper_shack_flush>, %X2
UNREACHABLE executed!
Stack dump:
0.      Running pass 'PowerPC Machine Code Emitter' on function
'@"8048150"'
Aborted

  Is this a bug in ppc JIT? Or I have to do something else
so that ppc JIT can call external functions?

  Thanks!

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Parallel Processing Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667

Hi, all

  I found the example code examples/HowToUseJIT.cpp also shows
the same error.

  Attachment is the LLVM module created by HowToUseJIT. And here
is the error,

Running foo:   %X4<def> = LDtoc <ga:@add1>, %X2
UNREACHABLE executed!
Stack dump:
0.      Running pass 'PowerPC Machine Code Emitter' on function
'@foo'
Aborted

  Currently, I use gdb try to track down where the problem is. Here
is the backtrace,

(gdb) bt
#0  0x00000fffb7b84090 in .raise () from /lib/libc.so.6
#1  0x00000fffb7b85ca4 in .abort () from /lib/libc.so.6
#2  0x0000000010517b9c in ._ZN4llvm25llvm_unreachable_internalEPKcS1_j ()
#3  0x0000000010047aa0 in
._ZN12_GLOBAL__N_114PPCCodeEmitter17getMachineOpValueERKN4llvm12MachineInstrERKNS1_14MachineOperandE
()
#4  0x0000000010048ff4 in
._ZN12_GLOBAL__N_114PPCCodeEmitter14emitBasicBlockERN4llvm17MachineBasicBlockE
()
#5  0x000000001004940c in
._ZN12_GLOBAL__N_114PPCCodeEmitter20runOnMachineFunctionERN4llvm15MachineFunctionE
()
#6  0x00000000101f26f4 in
._ZN4llvm19MachineFunctionPass13runOnFunctionERNS_8FunctionE ()
#7  0x00000000104b8634 in ._ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE
()
#8  0x00000000104b883c in ._ZN4llvm23FunctionPassManagerImpl3runERNS_8FunctionE
()
#9  0x00000000104b8b1c in ._ZN4llvm19FunctionPassManager3runERNS_8FunctionE ()
#10 0x0000000010020f64 in
._ZN4llvm3JIT14jitTheFunctionEPNS_8FunctionERKNS_10MutexGuardE ()
#11 0x0000000010021314 in
._ZN4llvm3JIT24runJITOnFunctionUnlockedEPNS_8FunctionERKNS_10MutexGuardE ()
#12 0x000000001002155c in ._ZN4llvm3JIT20getPointerToFunctionEPNS_8FunctionE ()
#13 0x00000000100236e4 in
._ZN4llvm3JIT11runFunctionEPNS_8FunctionERKSt6vectorINS_12GenericValueESaIS4_EE
()
#14 0x000000001000918c in main () at HowToUseJIT.cpp:116

  Any idea how can I further spot where is the bug? Thanks!

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Parallel Processing Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667

Forgot the attachment, sorry.

-- 
Wei-Ren Chen (陳韋任)
Parallel Processing Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
-------------- next part --------------
; ModuleID = 'test'

define i32 @add1(i32 %AnArg) {
EntryBlock:
  %addresult = add i32 1, %AnArg
  ret i32 %addresult
}

define i32 @foo() {
EntryBlock:
  %add1 = tail call i32 @add1(i32 10)
  ret i32 %add1
}

declare void @abort()

Hi, folks

  I saw the comments at the top of PowerPC/PPCCodeEmitter.cpp,
the ppc JIT is for PowerPC32 machine. But I am running a PowerPC64
machine. Could it be the reason why the ppc JIT cannot call external
functions?

  Thanks!

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Parallel Processing Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667

Hi, all
>   I found the example code examples/HowToUseJIT.cpp also shows
> the same error.
  At the end of inserting instruction into the Module created in
HowToUseJIT.cpp, I call function verifyModule to verify if everything
is O.K.. This time, it gave me much readable output,

Running foo: HowToUseJIT:
/tmp/chenwj/llvm-2.8/lib/Target/PowerPC/PPCCodeEmitter.cpp:156: unsigned
int<unnamed>::PPCCodeEmitter::getMachineOpValue(const
llvm::MachineInstr&, const llvm::MachineOperand&): Assertion
`MovePCtoLROffset && "MovePCtoLR not seen yet?"' failed.
Stack dump:
0.      Running pass 'PowerPC Machine Code Emitter' on function
'@foo'
Aborted

  The assert comes from PPCCodeEmitter.cpp.

if (TM.getRelocationModel() == Reloc::PIC_) {
  assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
}

  Which direction I should look into? Thanks!

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer System Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667