[Interpreter] Clean up the /usr/lib/swift fallback code.

- Check the target triple at runtime to decide whether to use the fallback.
- Change isInResourceDir to actually check the resource dir.
- Use ArrayRef<std::string> instead of std::vector<std::string>.

Author: mikeash

lib/Frontend/CompilerInvocation.cpp

@@ -30,10 +30,8 @@
 using namespace swift;
 using namespace llvm::opt;
 
-#if defined(__APPLE__) && defined(__MACH__)
-/// The path for Swift libraries in the OS.
-#define OS_LIBRARY_PATH "/usr/lib/swift"
-#endif
+/// The path for Swift libraries in the OS on Darwin.
+#define DARWIN_OS_LIBRARY_PATH "/usr/lib/swift"
 
 swift::CompilerInvocation::CompilerInvocation() {
   setTargetTriple(llvm::sys::getDefaultTargetTriple());
@@ -73,9 +71,8 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
   llvm::sys::path::append(LibPath, getPlatformNameForTriple(Triple));
   SearchPathOpts.RuntimeLibraryPaths.clear();
   SearchPathOpts.RuntimeLibraryPaths.push_back(LibPath.str());
-#if defined(__APPLE__) && defined(__MACH__)
-  SearchPathOpts.RuntimeLibraryPaths.push_back(OS_LIBRARY_PATH);
-#endif
+  if (Triple.isOSDarwin())
+    SearchPathOpts.RuntimeLibraryPaths.push_back(DARWIN_OS_LIBRARY_PATH);
 
   // Set up the import paths containing the swiftmodules for the libraries in
   // RuntimeLibraryPath.

lib/Frontend/ParseableInterfaceModuleLoader.cpp

@@ -1066,12 +1066,9 @@ class ParseableInterfaceModuleLoaderImpl {
   }
 
   bool isInResourceDir(StringRef path) {
-    for (auto &RuntimeLibraryPath : ctx.SearchPathOpts.RuntimeLibraryPaths) {
-      if (path.startswith(RuntimeLibraryPath)) {
-        return true;
-      }
-    }
-    return false;
+    StringRef resourceDir = ctx.SearchPathOpts.RuntimeResourcePath;
+    if (resourceDir.empty()) return false;
+    return path.startswith(resourceDir);
   }
 
   /// Finds the most appropriate .swiftmodule, whose dependencies are up to

lib/Immediate/Immediate.cpp

@@ -59,24 +59,25 @@ static void *loadRuntimeLib(StringRef runtimeLibPathWithName) {
 #endif
 }
 
-static void *loadRuntimeLib(StringRef sharedLibName, StringRef runtimeLibPath) {
+static void *loadRuntimeLibAtPath(StringRef sharedLibName,
+                                  StringRef runtimeLibPath) {
   // FIXME: Need error-checking.
   llvm::SmallString<128> Path = runtimeLibPath;
   llvm::sys::path::append(Path, sharedLibName);
   return loadRuntimeLib(Path);
 }
 
 static void *loadRuntimeLib(StringRef sharedLibName,
-                            const std::vector<std::string> runtimeLibPaths) {
+                            ArrayRef<std::string> runtimeLibPaths) {
   for (auto &runtimeLibPath : runtimeLibPaths) {
-    if (void *handle = loadRuntimeLib(sharedLibName, runtimeLibPath))
+    if (void *handle = loadRuntimeLibAtPath(sharedLibName, runtimeLibPath))
       return handle;
   }
   return nullptr;
 }
 
-void *swift::immediate::loadSwiftRuntime(const std::vector<std::string>
-                                         &runtimeLibPaths) {
+void *swift::immediate::loadSwiftRuntime(ArrayRef<std::string>
+                                         runtimeLibPaths) {
   return loadRuntimeLib("libswiftCore" LTDL_SHLIB_EXT, runtimeLibPaths);
 }
 

lib/Immediate/ImmediateImpl.h

@@ -37,8 +37,8 @@ namespace immediate {
 /// Returns a handle to the runtime suitable for other \c dlsym or \c dlclose
 /// calls or \c null if an error occurred.
 ///
-/// \param runtimeLibPath Path to search for compiler-relative stdlib dylibs.
-void *loadSwiftRuntime(const std::vector<std::string> &runtimeLibPaths);
+/// \param runtimeLibPaths Paths to search for stdlib dylibs.
+void *loadSwiftRuntime(ArrayRef<std::string> runtimeLibPaths);
 bool tryLoadLibraries(ArrayRef<LinkLibrary> LinkLibraries,
                       SearchPathOptions SearchPathOpts,
                       DiagnosticEngine &Diags);