compiler construction - LLVM How to detect when a specific ASM instruction sequence is generated -


i compiling c program using llvm. want know if particular assembly sequence generated , if generated, source code line associated with. example , want log every time push %eax instruction generated. there way approach problem?

in case others stumble upon similar problem.

the place looked @ llvms backend code. in particular concerned x86 assembly generation.

there 2 main areas modify , add tests.

  1. asmprinter class @ lib/codegen/asmprinter/asmprinter.cpp has different emit functions deal functions, basic blocks etc. go through them. these functions iterate through each machine instructions mi has functions getoperand() , getopcode() check specific instructions per requirement.

each specific opcode , actual instructions specified in target specific files eg.lib/target/x86/x86geninstrinfo.inc

  1. the above functions in turn call target specific subclass functions. in case x86asmprinter , similar classes.

to poke around add log statments such 

errs()<<"opcode "<<mi.getopcode()<<"\n"; mi.dump();

and can see these error messages when running llc file.bc

hope helps


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