One of the goals of the dependency scanner is to generate command-lines that can be used to explicitly build modular dependencies of a translation unit. The only modifications to these command-lines should be for the purposes of explicit modular build.
However, the current version of dependency scanner leaks its implementation details into the command-lines.
The first problem is that the `clang-scan-deps` tool adjusts the original textual command-line (adding `-Eonly -M -MT <target> -sys-header-deps -Wno-error -o /dev/null `, removing `--serialize-diagnostics`) in order to set up the `DependencyScanning` library. This has been addressed in D103461, D104012, D104030, D104031, D104033. With these patches, the `DependencyScanning` library receives the unmodified `CompilerInvocation`, sets it up and uses it for the implicit modular build.
Finally, to prevent leaking the implementation details to the resulting command-lines, this patch generates them from the **original** unmodified `CompilerInvocation` rather than from the one that drives the implicit build.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D104036
Jan Svoboda