Previously, given a CompilationDatabase with two commands for the same
source file we would report that file twice with the union of the
dependencies for each command both times.
This was due to the way `ClangTool` runs actions given an input source
file (see the comment in `DependencyScanningTool.cpp`). This commit adds
a `SingleCommandCompilationDatabase` that is created with each
`CompileCommand` in the original CDB, which is then used for each
`ClangTool` invocation. This gives us a single run of
`DependencyScanningAction` per `CompileCommand`.
I looked at using `AllTUsToolExecutor` which is a parallel tool
executor, but I'm not sure it's suitable for `clang-scan-deps` as it
does a lot more sharing of state than `AllTUsToolExecutor` expects.
Differential Revision: https://reviews.llvm.org/D69643
thread worker code and better error handling
This commit extracts out the code that will powers the fast scanning
worker into a new file in a new DependencyScanning library. The error
and output handling is improved so that the clients can gather
errors/results from the worker directly.
Differential Revision: https://reviews.llvm.org/D63681
llvm-svn: 364474
Michael Spencer