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Lincoln
Lincoln

Reputation: 1108

How to profile a program with llvm tools with llvm 3.5 or greater?

I am looking into using llvm tools to generate block level profile of small programs. It looks like in older versions this was as simple as running:

perl utils/profile.pl -block program.bc

How is profiling done in newer versions of LLVM?

Upvotes: 0

Views: 1727

Answers (1)

Shurannn
Shurannn

Reputation: 36

Use Clang and llvm-profdata

Visit the Clang User's Manual profile with instrumentation

llvm doc llvm-profdata

In summary:

  1. Build an instrumented version of the code 

    clang -O2 -fprofile-instr-generate code.c

  2. Run the instrumented executable to get the profile data file

    ./a.out

  3. Combine profiles from multiple runs and format the files by running

    llvm-profdata merge *.profraw -output=code.profdata

  4. Build the code again

    clang -O2 -fprofile-instr-use=code.profdata code.c

(Optional?) 5. Display the profile counters for this file and for any of the specified function(s)

    llvm-profdata show -all-functions code.profdata

Upvotes: 2

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