llvm-profdata - Profile data tool


llvm-profdata command [args…]


The llvm-profdata tool is a small utility for working with profile data files.




llvm-profdata merge [options] [filename…]


llvm-profdata merge takes several profile data files generated by PGO instrumentation and merges them together into a single indexed profile data file.

By default profile data is merged without modification. This means that the relative importance of each input file is proportional to the number of samples or counts it contains. In general, the input from a longer training run will be interpreted as relatively more important than a shorter run. Depending on the nature of the training runs it may be useful to adjust the weight given to each input file by using the -weighted-input option.

Profiles passed in via -weighted-input, -input-files, or via positional arguments are processed once for each time they are seen.



Print a summary of command line options.

-output=output, -o=output

Specify the output file name. Output cannot be - as the resulting indexed profile data can’t be written to standard output.


Specify an input file name along with a weight. The profile counts of the supplied filename will be scaled (multiplied) by the supplied weight, where where weight is a decimal integer >= 1. Input files specified without using this option are assigned a default weight of 1. Examples are shown below.

-input-files=path, -f=path

Specify a file which contains a list of files to merge. The entries in this file are newline-separated. Lines starting with ‘#’ are skipped. Entries may be of the form <filename> or <weight>,<filename>.

-remapping-file=path, -r=path

Specify a file which contains a remapping from symbol names in the input profile to the symbol names that should be used in the output profile. The file should consist of lines of the form <input-symbol> <output-symbol>. Blank lines and lines starting with # are skipped.

The llvm-cxxmap tool can be used to generate the symbol remapping file.

-instr (default)

Specify that the input profile is an instrumentation-based profile.


Specify that the input profile is a sample-based profile.

The format of the generated file can be generated in one of three ways:

-binary (default)

Emit the profile using a binary encoding. For instrumentation-based profile the output format is the indexed binary format.


Emit the profile in text mode. This option can also be used with both sample-based and instrumentation-based profile. When this option is used the profile will be dumped in the text format that is parsable by the profile reader.


Emit the profile using GCC’s gcov format (Not yet supported).


Do not emit function records with 0 execution count. Can only be used in conjunction with -instr. Defaults to false, since it can inhibit compiler optimization during PGO.

-num-threads=N, -j=N

Use N threads to perform profile merging. When N=0, llvm-profdata auto-detects an appropriate number of threads to use. This is the default.


Basic Usage

Merge three profiles:

llvm-profdata merge foo.profdata bar.profdata baz.profdata -output merged.profdata

Weighted Input

The input file foo.profdata is especially important, multiply its counts by 10:

llvm-profdata merge -weighted-input=10,foo.profdata bar.profdata baz.profdata -output merged.profdata

Exactly equivalent to the previous invocation (explicit form; useful for programmatic invocation):

llvm-profdata merge -weighted-input=10,foo.profdata -weighted-input=1,bar.profdata -weighted-input=1,baz.profdata -output merged.profdata



llvm-profdata show [options] [filename]


llvm-profdata show takes a profile data file and displays the information about the profile counters for this file and for any of the specified function(s).

If filename is omitted or is -, then llvm-profdata show reads its input from standard input.



Print details for every function.


Print the counter values for the displayed functions.


Print details for a function if the function’s name contains the given string.


Print a summary of command line options.

-output=output, -o=output

Specify the output file name. If output is - or it isn’t specified, then the output is sent to standard output.

-instr (default)

Specify that the input profile is an instrumentation-based profile.


Instruct the profile dumper to show profile counts in the text format of the instrumentation-based profile data representation. By default, the profile information is dumped in a more human readable form (also in text) with annotations.


Instruct the profile dumper to show the top n functions with the hottest basic blocks in the summary section. By default, the topn functions are not dumped.


Specify that the input profile is a sample-based profile.


Show the profiled sizes of the memory intrinsic calls for shown functions.


Show only those functions whose max count values are greater or equal to n. By default, the value-cutoff is set to 0.


Only output names of functions whose max count value are below the cutoff value.


llvm-profdata returns 1 if the command is omitted or is invalid, if it cannot read input files, or if there is a mismatch between their data.