RHEL: Look in more places to find g++ headers and runtime.

Some distros with ten years of support ship an old gcc but later offer
more recent versions for installation in parallel. These versions are
typically not only needed for the compilation of llvm/clang, but also to
properly use the clang binary that comes out.

Clang already searches /usr at runtime for the most recent installation
of gcc. This patch appends paths for add-on installations of gcc in
RHEL.

Patch by Michael Lampe.

llvm-svn: 268912

1 files changed, 10 insertions, 2 deletions

diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 1bf17e480d5..613ddb80f7e 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -1410,9 +1410,17 @@ void Generic_GCC::GCCInstallationDetector::init(
     // Then look for gcc installed alongside clang.
     Prefixes.push_back(D.InstalledDir + "/..");
 
-    // And finally in /usr.
-    if (D.SysRoot.empty())
+    // Then look for distribution supplied gcc installations.
+    if (D.SysRoot.empty()) {
+      // Look for RHEL devtoolsets.
+      Prefixes.push_back("/opt/rh/devtoolset-4/root/usr");
+      Prefixes.push_back("/opt/rh/devtoolset-3/root/usr");
+      Prefixes.push_back("/opt/rh/devtoolset-2/root/usr");
+      Prefixes.push_back("/opt/rh/devtoolset-1.1/root/usr");
+      Prefixes.push_back("/opt/rh/devtoolset-1.0/root/usr");
+      // And finally in /usr.
       Prefixes.push_back("/usr");
+    }
   }
 
   // Loop over the various components which exist and select the best GCC