be06761545
This fixes two problems with the 2-stage PGO builds. The first problem was that the stage2-instrumented and stage2 targets would not be built on the second ninja invocation. For example: This would work as expected. $ ninja -v -C build stage2-instrumented-generate-profdata Edit a file. $ touch llvm/lib/Support/StringExtras.cpp This would rebuild stage1 only and not build stage2-instrumented or regenerate the profile data. $ ninja -v -C build stage2-instrumented-generate-profdata The second problem was that in some cases, the profile data would be regenerated, but not all of the stage2 targets would be rebuilt. One common scenario where this would happen is: This would work as expected. $ ninja -C build stage2-check-all This would regenerate the profile data, but then only build the targets that were needed for install, but weren't needed for check-all. This would cause errors like: ld.lld: error: Function Import: link error: linking module flags 'ProfileSummary': IDs have conflicting values in ... This is because the executibles being built for the install target used the new profile data, but they were linking with libraries that used the old profile data. $ ninja -C build stage2-install With this change we can re-enable PGO for the release builds.
========================== Performance Training Data ========================== This directory contains simple source files for use as training data for generating PGO data and linker order files for clang.