ben.boeckel added a comment. In D139168#4027637 <https://reviews.llvm.org/D139168#4027637>, @ChuanqiXu wrote:
> Currently, clang-scan-deps won't check for this. If we have multiple command > lines with different `-MF` value, the make-style dependency information will > be written to these different depfiles. IMO, this is not suitable; there must be *one* depfile for Ninja to work (otherwise build tools will need to manually collate all of this into one for `ninja`. > I feel like we have 2 (or 3) options > > 1. (The current way) Extract `-MF` in the command line of clang (from > compilation database or from the args after `--`) See above; it works for the file-by-file, but falls over with batch scanning. > 2. (The original way) Specify `-MF` in the command line of clang-scan-deps. I feel this scales and communicates what is happening much better because it actually is a flag for `clang-scan-deps` itself. > 3. (Not good) Do nothing. I feel like it is possible for build systems to get > the make-style dependency information by scanning twice. One for P1689 > <https://reviews.llvm.org/P1689> format and one for make-format. It may be > workable but it sounds a little bit silly. In what mode will `clang` output `#include` information without erroring about missing `.pcm` files for `import` statements? `-E -fdirectives-only` perhaps? This further exacerbates the need for "fake" command lines and costs on platforms with expensive process execution. > the make-style dependency information of input_file in <dep_file> will be > overwritten. Or would cmake like to concat the results manually? Every command gets its own unique `<dep_file>`. Scanning, compilation, etc. Overlapping is just asking for race conditions in the build. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D139168/new/ https://reviews.llvm.org/D139168 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
