[driver] Pass a resource dir without the '/../' part.

This get the resource dir string to match with the one from libclang (which is not adding '/../'),
and allows clang to accept a modules-enabled PCH that was created by libclang.

llvm-svn: 296262

2 files changed, 20 insertions, 1 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index b8ae7e4c312..6defb204134 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -79,7 +79,8 @@ Driver::Driver(StringRef ClangExecutable, StringRef DefaultTargetTriple,
     llvm::sys::path::append(P, ClangResourceDir);
   } else {
     StringRef ClangLibdirSuffix(CLANG_LIBDIR_SUFFIX);
-    llvm::sys::path::append(P, "..", Twine("lib") + ClangLibdirSuffix, "clang",
+    P = llvm::sys::path::parent_path(Dir);
+    llvm::sys::path::append(P, Twine("lib") + ClangLibdirSuffix, "clang",
                             CLANG_VERSION_STRING);
   }
   ResourceDir = P.str();
diff --git a/clang/test/Index/pch-from-libclang.c b/clang/test/Index/pch-from-libclang.c
new file mode 100644
index 00000000000..e1bbe7cbd12
--- /dev/null
+++ b/clang/test/Index/pch-from-libclang.c
@@ -0,0 +1,18 @@
+// Check that clang can use a PCH created from libclang.
+// RUN: c-index-test -write-pch %t.h.pch %s -fmodules -fmodules-cache-path=%t.mcp
+// RUN: %clang -fsyntax-only -include %t.h %s -Xclang -verify -fmodules -fmodules-cache-path=%t.mcp -Xclang -detailed-preprocessing-record
+
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+struct S { int x; };
+
+#else
+
+void test(struct S *s) {
+  s->x = 0;
+}
+
+#endif