[PATCH] D140730: 59559 Explain code coverage with Lit in docs/SourceBasedCodeCoverage.rst

[Flash Sheridan via Phabricator via cfe-commits]

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The documentation for code coverage in docs/SourceBasedCodeCoverage.rst omits a couple of crucial steps when using it with Lit. I’d suggest the following additions:
At the end of “Running the instrumented program”:

> For a program such as the :doc:Lit <CommandGuide/lit> testing tool which
> invokes other programs, it may be necessary to set LLVM_PROFILE_FILE for
> each invocation. The pattern strings "%p" or "%Nm" may help to avoid
> corruption due to concurrency.

18 lines later, after “code-block:: console”:

> For an example of merging multiple profiles created by testing,
> see the LLVM coverage build script https://github.com/llvm/llvm-zorg/blob/main/zorg/jenkins/jobs/jobs/llvm-coverage_.




Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D140730

Files:
  clang/docs/SourceBasedCodeCoverage.rst


Index: clang/docs/SourceBasedCodeCoverage.rst
===================================================================
--- clang/docs/SourceBasedCodeCoverage.rst
+++ clang/docs/SourceBasedCodeCoverage.rst
@@ -127,6 +127,11 @@
 other platforms by passing the ``-runtime-counter-relocation`` option to the
 backend during compilation.
 
+For a program such as the :doc:`Lit <CommandGuide/lit>` testing tool which
+invokes other programs, it may be necessary to set ``LLVM_PROFILE_FILE`` for
+each invocation. The pattern strings "%p" or "%Nm" may help to avoid
+corruption due to concurrency.
+
 .. code-block:: console
 
     % clang++ -fprofile-instr-generate -fcoverage-mapping -mllvm -runtime-counter-relocation foo.cc -o foo
@@ -143,6 +148,9 @@
     # Step 3(a): Index the raw profile.
     % llvm-profdata merge -sparse foo.profraw -o foo.profdata
 
+For an example of merging multiple profiles created by testing,
+see the LLVM `coverage build script <https://github.com/llvm/llvm-zorg/blob/main/zorg/jenkins/jobs/jobs/llvm-coverage>`_.
+
 There are multiple different ways to render coverage reports. The simplest
 option is to generate a line-oriented report:
 


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