[LLVMdev] Cannot use function pass in a module pass

[John Criswell]

On 6/15/11 6:46 PM, Alexey Bakhirkin wrote:
> Hi. I'm trying to implement a module pass which can be dynamically
> loaded by `opt` (against up-to-date llvm from svn).
> Despite what the tutorial
> (http://llvm.org/docs/WritingAnLLVMPass.html) states in my module pass
> I cannot perform getAnalysis and fetch the function pass result.
> When trying to do so `opt` fails with the following mesage:

This may not be your problem, but in older versions of LLVM, you cannot 
call getAnalysis<FunctionPassName>(F) if F is a function with no body.  
You need to do something like:

if (!(F->isDeclaration())) {
     getAnalysis<FunctionPassName>(F);
     ...
}

-- John T.

> [***@*** ***]$ opt -load ~/llvm/Debug+Asserts/lib/MyPassLibrary.so
> -mymodulepass<  input.bc>/dev/null
> MyModulePass::runOnModule
> MyFunctionPass::runOnFunction(process)
> opt: /***/llvm/include/llvm/MyFunctionPass.h:241: AnalysisType&
> llvm::Pass::getAnalysisID(llvm::AnalysisID, llvm::Function&) [with
> AnalysisType = {anonymous}::MyFunctionPass, llvm::AnalysisID = const
> void*]: Assertion `ResultPass&&  "Unable to find requested analysis
> info"' failed.
> 0  opt             0x0000000000dbcd86
> 1  opt             0x0000000000dbcb82
> 2  libpthread.so.0 0x0000003b8f00eeb0
> 3  libc.so.6       0x0000003b8e835285 gsignal + 53
> 4  libc.so.6       0x0000003b8e836b9b abort + 379
> 5  libc.so.6       0x0000003b8e82dc0e
> 6  libc.so.6       0x0000003b8e82dcb2
> 7  MyPassLibrary.so 0x00007fb2989ce7e8
> 8  MyPassLibrary.so 0x00007fb2989ce59f
> 9  MyPassLibrary.so 0x00007fb2989ce401
> 10 opt             0x0000000000d39af7
> llvm::MPPassManager::runOnModule(llvm::Module&) + 453
> 11 opt             0x0000000000d39ff8
> llvm::PassManagerImpl::run(llvm::Module&) + 130
> 12 opt             0x0000000000d3a3ff llvm::PassManager::run(llvm::Module&) + 39
> 13 opt             0x00000000008c6803 main + 4561
> 14 libc.so.6       0x0000003b8e82139d __libc_start_main + 237
> 15 opt             0x00000000008b7b69
> Stack dump:
> 0.	Program arguments: opt -load
> /***/llvm/Debug+Asserts/lib/MyPassLibrary.so -mymodulepass
> 1.	Running pass 'My module pass' on module '<stdin>'.
> Aborted
>
> --------
>
> My code is similar to the following:
>
> #include "llvm/Pass.h"
> #include "llvm/Function.h"
> #include "llvm/Module.h"
> #include "llvm/Support/raw_ostream.h"
>
> using namespace llvm;
>
> namespace {
>    struct MyFunctionPass : public FunctionPass {
>      static char ID;
>      MyFunctionPass() : FunctionPass(ID) {};
>
>      virtual bool runOnFunction(Function&F) {
>        errs()<<  "MyFunctionPass::runOnFunction("<<  F.getName()<<  ")"<<  '\n';
>        return false;
>      }
>    };
> }
>
> char MyFunctionPass::ID = 0;
> static RegisterPass<MyFunctionPass>  MyFunctionPassPass("myfunctionpass",
>    "My function pass");
>
> namespace {
>    struct MyModulePass : public ModulePass {
>      static char ID;
>      MyModulePass() : ModulePass(ID) {};
>
>      virtual bool runOnModule(Module&M) {
>        errs()<<  "MyModulePass::runOnModule"<<  '\n';
>
>        for(Module::iterator FI=M.begin(), E=M.end(); FI!=E; ++FI) {
>          getAnalysis<MyFunctionPass>(*FI);
>        }
>
>        return false;
>      }
>
>      virtual void getAnalysisUsage(AnalysisUsage&AU) const {
>        AU.addRequired<MyFunctionPass>();
>      }
>    };
> }
>
> char MyModulePass::ID = 0;
> static RegisterPass<MyModulePass>  MyModulePassPass("mymodulepass",
>    "My module pass");
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