Fix the paths up a little, and address a linking issue on Windows.

The path to the runtime should be something like

  /usr/lib/swift/libswiftCore.dylib

So we want to strip lib/swift/ off to get the Swift root.

We also want auxiliary executables in

  /usr/libexec/swift

rather than just

  /usr/libexec

(While still supporting flat layout for Windows.)

rdar://103071801

Author: al45tair

stdlib/public/runtime/Paths.cpp

@@ -99,11 +99,13 @@ _swift_getDefaultRootPath()
   const char *ptr = runtimePath + runtimePathLen;
   while (ptr > runtimePath && !_swift_isPathSep(*--ptr));
 
-  // Remove the "lib" directory if it's present
-  if (ptr - runtimePath >= 4
-      && _swift_isPathSep(ptr[-4])
-      && std::strncmp(ptr - 3, "lib", 3) == 0) {
-    ptr -= 4;
+  // Remove lib/swift/ if present
+  if (ptr - runtimePath >= 10
+      && _swift_isPathSep(ptr[-10])
+      && std::strncmp(ptr - 9, "lib", 3) == 0
+      && _swift_isPathSep(ptr[-6])
+      && std::strncmp(ptr - 5, "swift", 5) == 0) {
+    ptr -= 10;
   }
 
   // If the result is empty, return "./" or ".\\"
@@ -152,9 +154,9 @@ swift_getAuxiliaryExecutablePath(const char *name)
 {
   const char *rootPath = swift_getRootPath();
 
-  // Form <rootPath>/libexec/
+  // Form <rootPath>/libexec/swift/
   size_t rootPathLen = std::strlen(rootPath);
-  const char *libexecStr = PATHSEP_STR "libexec" PATHSEP_STR;
+  const char *libexecStr = PATHSEP_STR "libexec" PATHSEP_STR "swift" PATHSEP_STR;
   size_t libexecLen = std::strlen(libexecStr);
   char *libexecPath = (char *)malloc(rootPathLen + libexecLen + 1);
   std::memcpy(libexecPath, rootPath, rootPathLen);

test/Runtime/Paths.cpp

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang %s -std=c++11 -I %swift_src_root/include -I %swift_src_root/stdlib/public/SwiftShims -I %clang-include-dir -isysroot %sdk %platform-dylib-dir/%target-library-name(swiftCore) -o %t/paths-test
+// RUN: %target-clang %s -std=c++11 -I %swift_src_root/include -I %swift_src_root/stdlib/public/SwiftShims -I %clang-include-dir -isysroot %sdk -L %swift_obj_root/lib/swift/%target-sdk-name -lswiftCore -o %t/paths-test
 // RUN: %target-codesign %t/paths-test
 // RUN: %target-run %t/paths-test | %FileCheck %s
 
@@ -45,6 +45,11 @@ isfile(const char *path) {
   return stat(path, &st) == 0 && !(st.st_mode & S_IFDIR);
 }
 
+static bool
+containsLibSwift(const char *path) {
+  return strstr(path, "/lib/swift/") != 0 || strstr(path, "\\lib\\swift\\") != 0;
+}
+
 int main(void) {
   const char *runtimePath = swift_getRuntimePath();
 
@@ -64,6 +69,12 @@ int main(void) {
   printf("root path: %s\n", rootPath ? rootPath : "<NULL>");
   printf("root is a directory: %s\n", isdir(rootPath) ? "yes" : "no");
 
+  // Root path should not contain /lib/swift
+
+  // CHECK: root path contains /lib/swift: no
+  printf("root path contains /lib/swift: %s\n",
+         containsLibSwift(rootPath) ? "yes" : "no");
+
   // Auxiliary executable path must be in swift-root/libexec.
 #define UNLIKELY_NAME "anUnlikelyExecutableName"