[PATCH] D32263: Preprocessor: Suppress -Wnonportable-include-path for header maps

[Duncan P. N. Exon Smith via Phabricator via cfe-commits]

dexonsmith created this revision.

If a file search involves a header map, suppress
-Wnonportable-include-path.  It's firing lots of false positives for
framework authors internally, and it's not trivial to fix.

Consider a framework called "Foo" with a main (installed) framework header
"Foo/Foo.h".  It's atypical for "Foo.h" to actually live inside a
directory called "Foo" in the source repository.  Instead, the
build system generates a header map while building the framework.
If Foo.h lives at the top-level of the source repository (common), and
the git repo is called ssh://some.url/foo.git, then the header map will
have something like:

  Foo/Foo.h -> /Users/myname/code/foo/Foo.h

where "/Users/myname/code/foo" is the clone of ssh://some.url/foo.git.

After #import <Foo/Foo.h>, the current implementation of
-Wnonportable-include-path will falsely assume that Foo.h was found in a
nonportable way, because of the name of the git clone (.../foo/Foo.h).
However, that directory name was not involved in the header search at
all.

This commit adds an extra parameter to Preprocessor::LookupFile and
HeaderSearch::LookupFile to track if the search used a header map,
making it easy to suppress the warning.  Longer term, once we find a way
to avoid the false positive, we should turn the warning back on.

rdar://problem/29849743


https://reviews.llvm.org/D32263

Files:
  clang/include/clang/Lex/HeaderSearch.h
  clang/include/clang/Lex/Preprocessor.h
  clang/lib/Lex/HeaderSearch.cpp
  clang/lib/Lex/PPDirectives.cpp
  clang/test/Preprocessor/Inputs/nonportable-hmaps/foo.hmap
  clang/test/Preprocessor/Inputs/nonportable-hmaps/headers/foo/Foo.h
  clang/test/Preprocessor/nonportable-include-with-hmap.c

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