[clang] d280a76 - [Driver][Linux] Fix regression when -DLIBCXX_LIBDIR_SUFFIX=64

[Fangrui Song via cfe-commits]

Author: Lin Sun
Date: 2021-08-25T23:50:17-07:00
New Revision: d280a76908e841da9e956a113d219e35247272bf

URL: https://github.com/llvm/llvm-project/commit/d280a76908e841da9e956a113d219e35247272bf
DIFF: https://github.com/llvm/llvm-project/commit/d280a76908e841da9e956a113d219e35247272bf.diff

LOG: [Driver][Linux] Fix regression when -DLIBCXX_LIBDIR_SUFFIX=64

This patch allows an installed (`ninja install-clang`) Clang to find
`../lib64/libc++.so`

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D108286

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/Linux.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
index caebab3a9aeb..3604a222ba4b 100644
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -303,8 +303,13 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
   // searched.
   // FIXME: It's not clear whether we should use the driver's installed
   // directory ('Dir' below) or the ResourceDir.
-  if (StringRef(D.Dir).startswith(SysRoot))
+  if (StringRef(D.Dir).startswith(SysRoot)) {
+    // Even if OSLibDir != "lib", this is needed for Clang in the build
+    // directory (not installed) to find libc++.
     addPathIfExists(D, D.Dir + "/../lib", Paths);
+    if (OSLibDir != "lib")
+      addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
+  }
 
   addPathIfExists(D, SysRoot + "/lib", Paths);
   addPathIfExists(D, SysRoot + "/usr/lib", Paths);