1 files changed, 19 insertions, 6 deletions
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 1eb7c9cdf2..67697569c4 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -2059,10 +2059,20 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
     addPathIfExists((GCCInstallation.getInstallPath() +
                      GCCInstallation.getMultiarchSuffix()),
                     Paths);
-    addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib/../" + Multilib,
-                    Paths);
-    addPathIfExists(LibPath + "/" + MultiarchTriple, Paths);
-    addPathIfExists(LibPath + "/../" + Multilib, Paths);
+
+    // If the GCC installation we found is inside of the sysroot, we want to
+    // prefer libraries installed in the parent prefix of the GCC installation.
+    // It is important to *not* use these paths when the GCC installation is
+    // outside of the system root as that can pick up un-intented libraries.
+    // This usually happens when there is an external cross compiler on the
+    // host system, and a more minimal sysroot available that is the target of
+    // the cross.
+    if (StringRef(LibPath).startswith(SysRoot)) {
+      addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib/../" + Multilib,
+                      Paths);
+      addPathIfExists(LibPath + "/" + MultiarchTriple, Paths);
+      addPathIfExists(LibPath + "/../" + Multilib, Paths);
+    }
   }
   addPathIfExists(SysRoot + "/lib/" + MultiarchTriple, Paths);
   addPathIfExists(SysRoot + "/lib/../" + Multilib, Paths);
@@ -2081,8 +2091,11 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
     const llvm::Triple &GCCTriple = GCCInstallation.getTriple();
     if (!GCCInstallation.getMultiarchSuffix().empty())
       addPathIfExists(GCCInstallation.getInstallPath(), Paths);
-    addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib", Paths);
-    addPathIfExists(LibPath, Paths);
+
+    if (StringRef(LibPath).startswith(SysRoot)) {
+      addPathIfExists(LibPath + "/../" + GCCTriple.str() + "/lib", Paths);
+      addPathIfExists(LibPath, Paths);
+    }
   }
   addPathIfExists(SysRoot + "/lib", Paths);
   addPathIfExists(SysRoot + "/usr/lib", Paths);