Object: replace backslashes with slashes in embedded relative thin archive paths on Windows.

[pcc]

Summary

This makes these thin archives portable between *nix and Windows.

[ruiu]

LGTM

As a side note, I like the way how Go standard library handles pathnames. In that language, '/' is always a path separator even on Windows, and that makes a lot of things much easier.

[grimar]

We had similar change in LLD, but did not use LLVM_ON_WIN32 define. May be it can be eliminated ?

[davide]

In D26696#597061, @grimar wrote:

We had similar change in LLD, but did not use LLVM_ON_WIN32 define. May be it can be eliminated ?

There's no point in replacing on *NIX as / is naturally the path separator there.

[grimar]

In D26696#597063, @davide wrote:

In D26696#597061, @grimar wrote:

We had similar change in LLD, but did not use LLVM_ON_WIN32 define. May be it can be eliminated ?

There's no point in replacing on *NIX as / is naturally the path separator there.

Yeah, I know. I mean that just helps to avoid use of define. Was just a suggestion, since we do in that way in LLD.

llvm/trunk/lib/Object/ArchiveWriter.cpp

static std::string computeRelativePath(StringRef From, StringRef To) {
 
   SmallString<128> Relative;
   for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
     sys::path::append(Relative, "..");
 
   for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
     sys::path::append(Relative, *ToI);
 
+#ifdef LLVM_ON_WIN32
+  // Replace backslashes with slashes so that the path is portable between *nix
+  // and Windows.
+  std::replace(Relative.begin(), Relative.end(), '\\', '/');
+#endif
+
   return Relative.str();
 }
 
 static void writeStringTable(raw_fd_ostream &Out, StringRef ArcName,
                              ArrayRef<NewArchiveMember> Members,
                              std::vector<unsigned> &StringMapIndexes,
                              bool Thin) {
   unsigned StartOffset = 0;

llvm/trunk/test/Object/archive-thin-paths.test

+REQUIRES: system-windows
+
+RUN: cd %T
+RUN: mkdir -p archive-thin-paths.dir
+RUN: echo foo > archive-thin-paths.dir/foo.o
+
+RUN: rm -f archive-thin-paths.a
+RUN: llvm-ar rcsT archive-thin-paths.a archive-thin-paths.dir\foo.o
+RUN: grep archive-thin-paths.dir/foo.o archive-thin-paths.a