Fix llvm-config support for CMake build-mode-style builds

[jordan_rose]

Summary

At some point we and/or CMake changed our build-mode-style builds from $LLVM_OBJ_ROOT/bin/$CMAKE_CFG_INTDIR/ to $LLVM_OBJ_ROOT/$CMAKE_CFG_INTDIR/bin/, which is way easier to use. But no one updated llvm-config.

Discovered when attempting to build libcxx with Xcode via Swift's build script, something that's probably not an interesting configuration to LLVM (or even so much to Swift). But it's good to be correct, right?

[jordan_rose]

tools/llvm-config/llvm-config.cpp

330

I'm not actually sure if LLVM_LIBDIR_SUFFIX is used here either, but it's not more wrong than it was before.

[beanz]

This fix looks good, although I would suggest that when building libcxx, using the LLVM CMake exports should be more reliable than llvm-confit.

[jordan_rose]

libcxx is using llvm-config to find the CMake exports; that's actually what prompted this change.

[jordan_rose]

Committed as rL369129.

tools/llvm-config/llvm-config.cpp

CurrentExecPrefix =
       sys::path::parent_path(sys::path::parent_path(CurrentPath)).str();
 
   // Check to see if we are inside a development tree by comparing to possible
   // locations (prefix style or CMake style).
   if (sys::fs::equivalent(CurrentExecPrefix, LLVM_OBJ_ROOT)) {
     IsInDevelopmentTree = true;
     DevelopmentTreeLayout = CMakeStyle;
     ActiveObjRoot = LLVM_OBJ_ROOT;
-  } else if (sys::fs::equivalent(CurrentExecPrefix,
-                                 Twine(LLVM_OBJ_ROOT) + "/bin")) {
+  } else if (sys::fs::equivalent(sys::path::parent_path(CurrentExecPrefix),
+                                 LLVM_OBJ_ROOT)) {
     IsInDevelopmentTree = true;
     DevelopmentTreeLayout = CMakeBuildModeStyle;
     ActiveObjRoot = LLVM_OBJ_ROOT;
   } else {
     IsInDevelopmentTree = false;
     DevelopmentTreeLayout = CMakeStyle; // Initialized to avoid warnings.
   }
 
if (IsInDevelopmentTree) {
     // layout.
     switch (DevelopmentTreeLayout) {
     case CMakeStyle:
       ActiveBinDir = ActiveObjRoot + "/bin";
       ActiveLibDir = ActiveObjRoot + "/lib" + LLVM_LIBDIR_SUFFIX;
       ActiveCMakeDir = ActiveLibDir + "/cmake/llvm";
       break;
     case CMakeBuildModeStyle:
+      // FIXME: Should we consider the build-mode-specific path as the prefix?
       ActivePrefix = ActiveObjRoot;
-      ActiveBinDir = ActiveObjRoot + "/bin/" + build_mode;
+      ActiveBinDir = ActiveObjRoot + "/" + build_mode + "/bin";
       ActiveLibDir =
-          ActiveObjRoot + "/lib" + LLVM_LIBDIR_SUFFIX + "/" + build_mode;
-      ActiveCMakeDir = ActiveLibDir + "/cmake/llvm";
+          ActiveObjRoot + "/" + build_mode + "/lib" + LLVM_LIBDIR_SUFFIX;
+      // The CMake directory isn't separated by build mode.
+      ActiveCMakeDir =
+          ActivePrefix + "/lib" + LLVM_LIBDIR_SUFFIX + "/cmake/llvm";
       break;
     }
 
     // We need to include files from both the source and object trees.
     ActiveIncludeOption =
         ("-I" + ActiveIncludeDir + " " + "-I" + ActiveObjRoot + "/include");
   } else {
     ActivePrefix = CurrentExecPrefix;