Take a better approach to detecting and selecting multiarch include

directories. This way we stop at the first multiarch directory found on
the system. This achieves the real intended result of pruning
non-existent directories.

llvm-svn: 143866

1 files changed, 35 insertions, 14 deletions

diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 3d4f12cb865..df01fc9d789 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -1995,23 +1995,44 @@ void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
   // Lacking those, try to detect the correct set of system includes for the
   // target triple.
 
-  // Generic Debian multiarch support:
+  // Implement generic Debian multiarch support.
+  const StringRef X86_64MultiarchIncludeDirs[] = {
+    "/usr/include/x86_64-linux-gnu",
+
+    // FIXME: These are older forms of multiarch. It's not clear that they're
+    // in use in any released version of Debian, so we should consider
+    // removing them.
+    "/usr/include/i686-linux-gnu/64",
+    "/usr/include/i486-linux-gnu/64"
+  };
+  const StringRef X86MultiarchIncludeDirs[] = {
+    "/usr/include/i386-linux-gnu",
+
+    // FIXME: These are older forms of multiarch. It's not clear that they're
+    // in use in any released version of Debian, so we should consider
+    // removing them.
+    "/usr/include/x86_64-linux-gnu/32",
+    "/usr/include/i686-linux-gnu",
+    "/usr/include/i486-linux-gnu"
+  };
+  const StringRef ARMMultiarchIncludeDirs[] = {
+    "/usr/include/arm-linux-gnueabi"
+  };
+  ArrayRef<StringRef> MultiarchIncludeDirs;
   if (getTriple().getArch() == llvm::Triple::x86_64) {
-    addExternCSystemInclude(DriverArgs, CC1Args,
-                            "/usr/include/x86_64-linux-gnu");
-    addExternCSystemInclude(DriverArgs, CC1Args,
-                            "/usr/include/i686-linux-gnu/64");
-    addExternCSystemInclude(DriverArgs, CC1Args,
-                            "/usr/include/i486-linux-gnu/64");
+    MultiarchIncludeDirs = X86_64MultiarchIncludeDirs;
   } else if (getTriple().getArch() == llvm::Triple::x86) {
-    addExternCSystemInclude(DriverArgs, CC1Args,
-                            "/usr/include/x86_64-linux-gnu/32");
-    addExternCSystemInclude(DriverArgs, CC1Args, "/usr/include/i686-linux-gnu");
-    addExternCSystemInclude(DriverArgs, CC1Args, "/usr/include/i486-linux-gnu");
-    addExternCSystemInclude(DriverArgs, CC1Args, "/usr/include/i386-linux-gnu");
+    MultiarchIncludeDirs = X86MultiarchIncludeDirs;
   } else if (getTriple().getArch() == llvm::Triple::arm) {
-    addExternCSystemInclude(DriverArgs, CC1Args,
-                            "/usr/include/arm-linux-gnueabi");
+    MultiarchIncludeDirs = ARMMultiarchIncludeDirs;
+  }
+  for (ArrayRef<StringRef>::iterator I = MultiarchIncludeDirs.begin(),
+                                     E = MultiarchIncludeDirs.end();
+       I != E; ++I) {
+    if (llvm::sys::fs::exists(*I)) {
+      addExternCSystemInclude(DriverArgs, CC1Args, D.SysRoot + *I);
+      break;
+    }
   }
 
   if (getTriple().getOS() == llvm::Triple::RTEMS)