Add vfs::FileSystem::getRealPath

[ioeric]

Summary

And change FileManager::getCanonicalName to use getRealPath.

[ioeric]

• Add vfs::FileSystem::getRealPath; change getCanonicalName to use getRealPath

[bkramer]

Looks good. Please watch the windows buildbots carefully after landing this.

lib/Basic/FileManager.cpp

542

PATH_MAX is not a standard thing and probably not there on windows. I'd just hardcode it to 256.

[ioeric]

• s/PATH_MAX/4096/

lib/Basic/FileManager.cpp

542

PATH_MAX on unit is 4096. Let's go with 4096.

lib/Basic/FileManager.cpp

 
 StringRef FileManager::getCanonicalName(const DirectoryEntry *Dir) {
   // FIXME: use llvm::sys::fs::canonical() when it gets implemented
   llvm::DenseMap<const DirectoryEntry *, llvm::StringRef>::iterator Known
     = CanonicalDirNames.find(Dir);
   if (Known != CanonicalDirNames.end())
     return Known->second;
 
-  StringRef CanonicalName(Dir->getName());
+  // Canonical name should still be an absolute path even if realpath fails.
+  llvm::SmallString<128> AbsDirPath(Dir->getName());
+  makeAbsolutePath(AbsDirPath);
+  StringRef CanonicalName = AbsDirPath.str().copy(CanonicalNameStorage);
 
 #ifdef LLVM_ON_UNIX
   char CanonicalNameBuf[PATH_MAX];
-  if (realpath(Dir->getName().str().c_str(), CanonicalNameBuf))
+  if (realpath(AbsDirPath.c_str(), CanonicalNameBuf))
     CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage);
 #else
   SmallString<256> CanonicalNameBuf(CanonicalName);
-  llvm::sys::fs::make_absolute(CanonicalNameBuf);
   llvm::sys::path::native(CanonicalNameBuf);
   // We've run into needing to remove '..' here in the wild though, so
   // remove it.
   // On Windows, symlinks are significantly less prevalent, so removing
   // '..' is pretty safe.
   // Ideally we'd have an equivalent of `realpath` and could implement
   // sys::fs::canonical across all the platforms.
   llvm::sys::path::remove_dots(CanonicalNameBuf, /* remove_dot_dot */ true);

unittests/Basic/FileManagerTest.cpp

#endif
 
   SmallString<64> ExpectedResult(CustomWorkingDir);
   llvm::sys::path::append(ExpectedResult, Path);
 
   ASSERT_TRUE(Manager.makeAbsolutePath(Path));
   EXPECT_EQ(Path, ExpectedResult);
 }
 
+TEST_F(FileManagerTest, GetCanonicalNameReturnsAbsolutePathOnVFS) {
+  SmallString<64> CustomWorkingDir;
+#ifdef _WIN32
+  CustomWorkingDir = "C:\\test";
+#else
+  CustomWorkingDir = "/test";
+#endif
+  llvm::sys::path::append(CustomWorkingDir, "some", "weird", "path");
+
+  auto FS =
+      IntrusiveRefCntPtr<vfs::InMemoryFileSystem>(new vfs::InMemoryFileSystem);
+  // setCurrentworkingdirectory must finish without error.
+  ASSERT_TRUE(!FS->setCurrentWorkingDirectory(CustomWorkingDir));
+  SmallString<64> FooPath("weird/foo/foo.cpp");
+  FS->addFile(FooPath.str(), 0, llvm::MemoryBuffer::getMemBuffer(""));
+
+  FileSystemOptions Opts;
+  FileManager Manager(Opts, FS);
+
+  // Use relative path to open the directory.
+  const DirectoryEntry *Dir =
+      Manager.getDirectory(llvm::sys::path::parent_path(FooPath.str()));
+  EXPECT_TRUE(Dir != nullptr);
+  EXPECT_FALSE(llvm::sys::path::is_absolute(Dir->getName()));
+
+  SmallString<64> AbsFooPath(CustomWorkingDir);
+  llvm::sys::path::append(AbsFooPath, FooPath);
+  EXPECT_EQ(Manager.getCanonicalName(Dir),
+            llvm::sys::path::parent_path(AbsFooPath.str()));
+}
+
 } // anonymous namespace