[vfs] Allow root paths relative to the vfsoverlay YAML file

This change adds 'root-relative' option in vfsoverlay YAML file format
so the root patchs can be relative to the YAML file directory instead of
the current working directory.

Differential Revision: https://reviews.llvm.org/D137473

1 files changed, 70 insertions, 5 deletions

diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index e4f93ca..242bb76 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -1456,18 +1456,20 @@ public:
 
   std::unique_ptr<vfs::FileSystem>
   getFromYAMLRawString(StringRef Content,
-                       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS) {
+                       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS,
+                       StringRef YAMLFilePath = "") {
     std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBuffer(Content);
-    return getVFSFromYAML(std::move(Buffer), CountingDiagHandler, "", this,
-                          ExternalFS);
+    return getVFSFromYAML(std::move(Buffer), CountingDiagHandler, YAMLFilePath,
+                          this, ExternalFS);
   }
 
   std::unique_ptr<vfs::FileSystem> getFromYAMLString(
       StringRef Content,
-      IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem()) {
+      IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem(),
+      StringRef YAMLFilePath = "") {
     std::string VersionPlusContent("{\n  'version':0,\n");
     VersionPlusContent += Content.slice(Content.find('{') + 1, StringRef::npos);
-    return getFromYAMLRawString(VersionPlusContent, ExternalFS);
+    return getFromYAMLRawString(VersionPlusContent, ExternalFS, YAMLFilePath);
   }
 
   // This is intended as a "XFAIL" for windows hosts.
@@ -1853,6 +1855,69 @@ TEST_F(VFSFromYAMLTest, ReturnsExternalPathVFSHit) {
   EXPECT_EQ(0, NumDiagnostics);
 }
 
+TEST_F(VFSFromYAMLTest, RootRelativeTest) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addDirectory("//root/foo/bar");
+  Lower->addRegularFile("//root/foo/bar/a");
+  IntrusiveRefCntPtr<vfs::FileSystem> FS =
+      getFromYAMLString("{\n"
+                        "  'case-sensitive': false,\n"
+                        "  'root-relative': 'overlay-dir',\n"
+                        "  'roots': [\n"
+                        "    { 'name': 'b', 'type': 'file',\n"
+                        "      'external-contents': '//root/foo/bar/a'\n"
+                        "    }\n"
+                        "  ]\n"
+                        "}",
+                        Lower, "//root/foo/bar/overlay");
+
+  ASSERT_NE(FS.get(), nullptr);
+  ErrorOr<vfs::Status> S = FS->status("//root/foo/bar/b");
+  ASSERT_FALSE(S.getError());
+  EXPECT_EQ("//root/foo/bar/a", S->getName());
+
+  // On Windows, with overlay-relative set to true, the relative
+  // path in external-contents field will be prepend by OverlayDir
+  // with native path separator, regardless of the actual path separator
+  // used in YAMLFilePath field.
+#ifndef _WIN32
+  FS = getFromYAMLString("{\n"
+                         "  'case-sensitive': false,\n"
+                         "  'overlay-relative': true,\n"
+                         "  'root-relative': 'overlay-dir',\n"
+                         "  'roots': [\n"
+                         "    { 'name': 'b', 'type': 'file',\n"
+                         "      'external-contents': 'a'\n"
+                         "    }\n"
+                         "  ]\n"
+                         "}",
+                         Lower, "//root/foo/bar/overlay");
+  ASSERT_NE(FS.get(), nullptr);
+  S = FS->status("//root/foo/bar/b");
+  ASSERT_FALSE(S.getError());
+  EXPECT_EQ("//root/foo/bar/a", S->getName());
+#else
+  IntrusiveRefCntPtr<DummyFileSystem> LowerWindows(new DummyFileSystem());
+  LowerWindows->addDirectory("\\\\root\\foo\\bar");
+  LowerWindows->addRegularFile("\\\\root\\foo\\bar\\a");
+  FS = getFromYAMLString("{\n"
+                         "  'case-sensitive': false,\n"
+                         "  'overlay-relative': true,\n"
+                         "  'root-relative': 'overlay-dir',\n"
+                         "  'roots': [\n"
+                         "    { 'name': 'b', 'type': 'file',\n"
+                         "      'external-contents': 'a'\n"
+                         "    }\n"
+                         "  ]\n"
+                         "}",
+                         LowerWindows, "\\\\root\\foo\\bar\\overlay");
+  ASSERT_NE(FS.get(), nullptr);
+  S = FS->status("\\\\root\\foo\\bar\\b");
+  ASSERT_FALSE(S.getError());
+  EXPECT_EQ("\\\\root\\foo\\bar\\a", S->getName());
+#endif
+}
+
 TEST_F(VFSFromYAMLTest, ReturnsInternalPathVFSHit) {
   IntrusiveRefCntPtr<vfs::InMemoryFileSystem> BaseFS(
       new vfs::InMemoryFileSystem);