Problem initializing a JIT via C bindings

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#1

Hi all,

I have some code that uses the x86 JIT via the C bindings that I'm trying to migrate from targeting LLVM 2.5 to the top of tree, but I'm running into a linking problem I can't figure out.

Here's how I'm invoking the JIT in 2.5.

LLVMInitializeNativeTarget(); <-- for the updated version
LLVMCreateMemoryBufferWithContentsOfFile("code.bc", &buffer, &err);
LLVMGetBitcodeModuleProvider(buffer, &provider, &err);
LLVMCreateJITCompiler(&engine, provider, 1, &err);

After that LLVMFindFunction and RunFunction work wonderfully on 2.5. The TOT version errors out on the CreateJITCompiler call with a "JIT has not been linked in" message.

I'm compiling it as follows, which completes with no errors on either LLVM version.

LLVM_CONFIG=<the llvm-config from the version I want to use>
gcc `$LLVM_CONFIG --cflags` -o main.o -c main.c
g++ `$LLVM_CONFIG --cflags` \
    `$LLVM_CONFIG --ldflags` \
    main.o `$(LLVM_CONFIG) --libfiles engine BitReader`

Am I missing some other post 2.5 API change or am I building things wrong?

Thanks,

- Dave

#2

Keppler, Dave wrote:

Hi all,

I have some code that uses the x86 JIT via the C bindings that I'm trying to migrate from targeting LLVM 2.5 to the top of tree, but I'm running into a linking problem I can't figure out.

Here's how I'm invoking the JIT in 2.5.

LLVMInitializeNativeTarget(); <-- for the updated version
LLVMCreateMemoryBufferWithContentsOfFile("code.bc", &buffer, &err);
LLVMGetBitcodeModuleProvider(buffer, &provider, &err);
LLVMCreateJITCompiler(&engine, provider, 1, &err);

After that LLVMFindFunction and RunFunction work wonderfully on 2.5. The TOT version errors out on the CreateJITCompiler call with a "JIT has not been linked in" message.

I'm compiling it as follows, which completes with no errors on either LLVM version.

LLVM_CONFIG=<the llvm-config from the version I want to use>
gcc `$LLVM_CONFIG --cflags` -o main.o -c main.c
g++ `$LLVM_CONFIG --cflags` \
    `$LLVM_CONFIG --ldflags` \
    main.o `$(LLVM_CONFIG) --libfiles engine BitReader`

Am I missing some other post 2.5 API change or am I building things wrong?

Add "jit native" to the list of components you're passing to llvm-config.

Nick

#3

I'm compiling it as follows, which completes with no errors on either

LLVM version.

LLVM_CONFIG=<the llvm-config from the version I want to use>
gcc `$LLVM_CONFIG --cflags` -o main.o -c main.c
g++ `$LLVM_CONFIG --cflags` \
    `$LLVM_CONFIG --ldflags` \
    main.o `$(LLVM_CONFIG) --libfiles engine BitReader`

Am I missing some other post 2.5 API change or am I building things

wrong?

Add "jit native" to the list of components you're passing to llvm-config.

Nick

For me 'jit native' and 'engine' produce equivalent lists of libraries.

Did my code look correct otherwise? There must be something broken on my system if that's the case.

- Dave

#4

Keppler, Dave wrote:

I'm compiling it as follows, which completes with no errors on either

LLVM version.

LLVM_CONFIG=<the llvm-config from the version I want to use>
gcc `$LLVM_CONFIG --cflags` -o main.o -c main.c
g++ `$LLVM_CONFIG --cflags` \
    `$LLVM_CONFIG --ldflags` \
    main.o `$(LLVM_CONFIG) --libfiles engine BitReader`

Am I missing some other post 2.5 API change or am I building things

wrong?

Add "jit native" to the list of components you're passing to llvm-config.

Nick

For me 'jit native' and 'engine' produce equivalent lists of libraries.

Did my code look correct otherwise? There must be something broken on my system if that's the case.

I think you should use --cxxflags when running with g++, but that wouldn't cause this error. I don't see anything obviously wrong here.

Nick