[cmake] Fix relative paths in prefix map #74132
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Previously, building a debug version of LLVM when -ffile-prefix-map would cause llvm project paths to be prefixed by the build directory, so source locations would be "../build/llvm/...". This happened because the relative path went in the wrong direction, from source-dir to build-dir instead of from build-dir to source-dir. This patch swaps the directionality of the relative paths so that they get a proper prefix from the build directory. Given a build dir at /build and a project directory at /llvm-project, we get source locations like: "../llvm-project/llvm/lib/Transforms/...", which a debugger can resolve once pointed to the correct directory.
petrhosek
approved these changes
Dec 1, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When building debug version of LLVM with
LLVM_USE_RELATIVE_PATHS_IN_FILES=Onwould cause source paths to be incorrect, and be prefixed by the build directory. This lead to source locations like the following:../build/llvm/.... Such paths do not exist, and existing debuggers can't adjust their search location because of the incorrect prefix. Ultimately, this happened because the relative path creation goes in the wrong direction, from source-dir to build-dir instead of from build-dir to source-dir.This patch swaps the directionality of the relative paths so that they get a proper prefix from the build directory. Given a build dir at
/buildand a project directory at/llvm-project, we get source locations like:../llvm-project/llvm/lib/Transforms/..., which a debugger can resolve once pointed to the correct project directory.