[PATCH] D41911: [clangd] Include scanner that finds compile commands for headers.

[Sam McCall via Phabricator via cfe-commits]

sammccall marked 2 inline comments as done.
sammccall added a comment.

Context here, this patch is over a year old and predates the work on heuristically picking a compile command from another file in the CDB.

I don't think anyone has concrete plans to revive this, the heuristics work well enough and often enough. I should probably have abandoned this patch, sorry for the time lost in detailed comments.

However there's certainly some value in indexing the include graph and/or determining main-file/header pairs.
e.g. to improve switchsourceheader, to enable cross-file refactorings like "out-line implementation". And maybe to improve compile command accuracy too.

This patch was pretty narrowly tailored at getting compile commands quickly, if we developed this approach it should probably be more general purpose, part of the index, and maybe take symbol declaration/definition into account rather than just #includes.



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Comment at: clangd/IncludeScanner.cpp:131
+  IgnoringDiagConsumer IgnoreDiags;
+  // XXX the VFS working directory is global state, this is unsafe.
+  Cmd.VFS->setCurrentWorkingDirectory(Cmd.Directory);
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klimek wrote:
> I assume that's a note to you that you want to change this?
This has since been fixed, it's no longer global state :-)


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Comment at: clangd/IncludeScanner.cpp:159
+  // When reusing flags, we add an explicit `-x cpp` to override the extension.
+  // TODO: copying CompilerInvocation would avoid this, and is more robust.
+  if (std::find(Cmd.CommandLine.begin(), Cmd.CommandLine.end(), "-x") ==
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klimek wrote:
> Wondering why we can't use one of the tooling abstractions here...
As far as I can tell, the only abstraction Tooling offers here is CompileCommand, the only way to robustly manipulate it is through the Driver (the semantics here are too subtle for brute-force string manipulation). InterpolatingCompilationDatabase does this, but doesn't expose the primitives publicly. It could if there was a need.


Repository:
  rCTE Clang Tools Extra

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  https://reviews.llvm.org/D41911/new/

https://reviews.llvm.org/D41911