[LLVMdev] How to get llvm bitcode executed

[Xiaolong Tang]

Hi Duncan, 

Thanks again. 

> > As Duncan described, "lli -load=libstdc++.dylib ..." works. I,
> > however, encounted an "Illegal instruction" message, while I was
> > trying to interpret a large program.
> 
> are you using the interpreter or the JIT?

I think, I am using the JIT, as passing -force-interpreter=true gives
rise to "Could not resolve external global address: __dso_handle". 
The "Illegal instruction" issue might be caused by the program I
attempted to run; I am investigating this issue.


>   So, does lli have a debug switch
> > for dumping out the details for errors?
> >
> > Using llc is not that simple, and I have not gotten through the
> > compilation process. For instance, "llc -o test.s test.bc" works and
> > generates "test.s"; "g++ -o test.o test.s" throws out "Unknown
> > pseudo-op: .cfi_startproc" messages, however. Not sure about the
> > reasons yet.
> 
> This means that your binutils is too old.  Try passing -disable-cfi
> to llc.
> 

This option works. Actually, the version of my assembler (as) is GNU
assembler version 1.38. I have no idea of the up-to-date version for
working with llc, but the "-disable-cfi" options helps out, even under
my outdated binutils.

Best, 
Xiaolong



> >>
> >>> I have a program that uses C++ STL a lot. To have the source code for
> >>> STL functions, I undefined "_GLIBCXX_EXTERN_TEMPLATE" in
> >>> c++config.h. In spite of this, after compilation (via clang) and
> >>> linking (via llvm-ld), the resulting bitcode contains a few declared
> >>> functions (with no definitions).
> >>>
> >>> My question is: In the scenario where some function definitions are
> >>> missing in a llvm bitcode, can we get a way to run this module via llc
> >>> or lli? Or is there any way to make these function definitions
> >>> available in the llvm bitcode?
> >>
> >> with lli, you should be able to do it by adding
> >>     -load=libstdc++.so
> >> to the lli command line (maybe with a full path).  With llc, use g++
> >> to the linking.  For example, if llc turned bitcode.bc into bitcode.s,
> >> do
> >>     g++ -o bitcode bitcode.s
> >> since g++ automagically passes libstdc++ to the linker.  You can also
> >> use the system linker directly, adding the missing libraries.
> >>
> >>>
> >>> Specifically, these missing functions are as below:
> >>>
> >>>     declare i8* @llvm.eh.exception() nounwind readonly
> >>
> >> This is an LLVM intrinsic, so isn't really missing.
> >>
> >>>     declare i32 @__gxx_personality_v0(...)
> >>
> >> This should be in libstdc++.
> >>
> >>>     declare i32 @llvm.eh.selector(i8*, i8*, ...) nounwind
> >>>     declare void @llvm.eh.resume(i8*, i32)
> >>
> >> LLVM intrinsics.
> >>
> >>>     declare void @_ZSt9terminatev()
> >>
> >> This should be in libstdc++.
> >>
> >>>     declare i32 @memcmp(i8*, i8*, i64)
> >>
> >> In libc (libc.so) which should be pulled in by libstdc++.
> >>
> >>>     declare i64 @llvm.expect.i64(i64, i64) nounwind readnone
> >>
> >> LLVM intrinsic.
> >>
> >>>     declare void @_ZSt19__throw_logic_errorPKc(i8*) noreturn
> >>>     declare i8* @__cxa_begin_catch(i8*)
> >>>     declare void @__cxa_rethrow()
> >>>     declare void @__cxa_end_catch()
> >>>     declare void @__cxa_call_unexpected(i8*)
> >>>     declare void @_ZdlPv(i8*) nounwind
> >>>     declare void @_ZSt20__throw_length_errorPKc(i8*) noreturn
> >>>     declare void @_ZSt17__throw_bad_allocv() noreturn
> >>>     declare noalias i8* @_Znwm(i64)
> >>
> >> These should all be in libstdc++.
> >>
> >>>     declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
> >>>     declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
> >>>     declare i32 @llvm.atomic.load.add.i32.p0i32(i32* nocapture, i32) nounwind
> >>>     declare void @llvm.memory.barrier(i1, i1, i1, i1, i1) nounwind
> >>
> >> LLVM intrinsics.
> >>
> >>>     declare void @_ZSt20__throw_out_of_rangePKc(i8*) noreturn
> >>
> >> This should be in libstdc++.
> >>
> >>>     declare i64 @strlen(i8*)
> >>>     declare void @abort()
> >>
> >> In libc (libc.so) which should be pulled in by libstdc++.
> >>
> >> Ciao, Duncan.
> >>
> >>>
> >>>
> >>> Xiaolong
> >>> _______________________________________________
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> >>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >>
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