[PATCH] D83154: clang: Add -fcoverage-prefix-map

[Reid "Away June-Sep" Kleckner via Phabricator via cfe-commits]

rnk added inline comments.


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Comment at: clang/lib/CodeGen/CoverageMappingGen.cpp:1334
+  llvm::SmallString<256> Path(Filename);
+  llvm::sys::fs::make_absolute(Path);
+  llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
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keith wrote:
> rnk wrote:
> > Please only make the path absolute if nothing in the prefix map matches. Otherwise, the user must embed the CWD into the prefix map, which is needlessly difficult for the build system. I believe it is also consistent with the way that the debug info prefix map works. It appears to operate on the possibly relative source paths received on the command line (-I...).
> Are you suggesting that I try to remap them relatively, and if that fails, absolutize it and attempt the remapping again? Or don't absolutize them at all anymore?
I'd prefer to do the remapping once without any absolutization, and if that fails, preserve the behavior of absolutizing.

It would be my preference to not absolutize paths at all, since that is what is done for debug info. However, @vsk implemented things this way, and I do understand that this is convenient default behavior for most users: the paths in the coverage are valid anywhere on their system. So, changing this behavior is out of scope for this patch.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D83154/new/

https://reviews.llvm.org/D83154