CODEWITHSUNDEEP
llvminlinellvm-c++-api
user552285
user552285

Reputation: 409

llvm inliner pass doesn't work

I have wrote a wrapper over a function and i want to inline it (this wrapper just maps the arguments for the original function in another way). I am trying to call the inliner in llvm over my module after my changes and it doesn't do the work, although i tried calling the pass from opt tool and it worked, Any idea what's may be wrong ?

Here is how i call the inliner pass:

llvm::PassManager my_passes;
my_passes.add(llvm::createFunctionInliningPass(4096));
my_passes.run(module);

Upvotes: 5

Views: 1084

Answers (1)

AlexK
AlexK

Reputation: 205

I've managed to get the "AlwaysInline" pass working. The steps were much like what you describe:

llvm::Module m("MyJIT", llvm::getGlobalContext());
llvm::PassManager pm;
pm.add(llvm::createAlwaysInlinerPass());
...

llvm::Function* f = buildMyFunction();
f->addAttribute(llvm::AttributeSet::FunctionIndex, llvm::Attribute::AlwaysInline);
...

llvm::DebugFlag = true;
pm.runOnModule(m);
m.dump();

Note the llvm::DebugFlag variable, which will cause the llvm code generation machinery to spew a healthy amount of diagnostic output. It's declared in llvm/Support/Debug.h and can be changed from your code or from gdb via set llvm::DebugFlag = 1.

Also try poking around the llvm source; the relevant bits will be in ${llvm_root_dir}/lib/Transforms/IPO/Inliner.cpp

Upvotes: 3

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