Teach Clang to look in its installation libdir for libraries (such as

libc++) when the installation is within the system root.

This doesn't really help cross compiles much, but we don't (currently)
have a great story around libc++, cross compiles, and who is responsible
for building and/or installing the libraries. However, it handles the
very common case of non-cross builds in a way entirely consistent with
GCC, so I'm hopeful this won't really hose anyone.

This is the second patch that I think should be backported to 3.4 to
give folks an easy to checkout and install working Clang+libc++
toolchain.

llvm-svn: 199769

2 files changed, 46 insertions, 0 deletions

diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index b8d9639e9c2..b7cb874e079 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -2695,6 +2695,17 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
       addPathIfExists(LibPath + "/../" + Multilib, Paths);
     }
   }
+
+  // Similar to the logic for GCC above, if we currently running Clang inside
+  // of the requested system root, add its parent multilib library paths to
+  // those 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)) {
+    addPathIfExists(D.Dir + "/../lib/" + MultiarchTriple, Paths);
+    addPathIfExists(D.Dir + "/../" + Multilib, Paths);
+  }
+
   addPathIfExists(SysRoot + "/lib/" + MultiarchTriple, Paths);
   addPathIfExists(SysRoot + "/lib/../" + Multilib, Paths);
   addPathIfExists(SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
@@ -2723,6 +2734,15 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
     if (StringRef(LibPath).startswith(SysRoot))
       addPathIfExists(LibPath, Paths);
   }
+
+  // Similar to the logic for GCC above, if we are currently running Clang
+  // inside of the requested system root, add its parent library path to those
+  // 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))
+    addPathIfExists(D.Dir + "/../lib", Paths);
+
   addPathIfExists(SysRoot + "/lib", Paths);
   addPathIfExists(SysRoot + "/usr/lib", Paths);
 }
diff --git a/clang/test/Driver/linux-ld.c b/clang/test/Driver/linux-ld.c
index 9e9aa3508d7..52f015f3625 100644
--- a/clang/test/Driver/linux-ld.c
+++ b/clang/test/Driver/linux-ld.c
@@ -214,6 +214,32 @@
 // CHECK-GCC-VERSION4: "{{.*}}/Inputs/gcc_version_parsing4/bin/../lib/gcc/i386-unknown-linux/4.7.99{{/|\\\\}}crtbegin.o"
 // CHECK-GCC-VERSION4: "-L{{.*}}/Inputs/gcc_version_parsing4/bin/../lib/gcc/i386-unknown-linux/4.7.99"
 //
+// Test a simulated installation of libc++ on Linux, both through sysroot and
+// the installation path of Clang.
+// RUN: %clangxx -no-canonical-prefixes -x c++ %s -### -o %t.o 2>&1 \
+// RUN:     -target x86_64-unknown-linux-gnu \
+// RUN:     -stdlib=libc++ \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-SYSROOT %s
+// CHECK-BASIC-LIBCXX-SYSROOT: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
+// CHECK-BASIC-LIBCXX-SYSROOT: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-BASIC-LIBCXX-SYSROOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
+// CHECK-BASIC-LIBCXX-SYSROOT: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-BASIC-LIBCXX-SYSROOT: "--sysroot=[[SYSROOT]]"
+// RUN: %clang -no-canonical-prefixes -x c++ %s -### -o %t.o 2>&1 \
+// RUN:     -target x86_64-unknown-linux-gnu \
+// RUN:     -stdlib=libc++ \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_libcxx_tree/usr/bin \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-INSTALL %s
+// CHECK-BASIC-LIBCXX-INSTALL: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
+// CHECK-BASIC-LIBCXX-INSTALL: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-BASIC-LIBCXX-INSTALL: "-internal-isystem" "[[SYSROOT]]/usr/bin/../include/c++/v1"
+// CHECK-BASIC-LIBCXX-INSTALL: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-BASIC-LIBCXX-INSTALL: "--sysroot=[[SYSROOT]]"
+// CHECK-BASIC-LIBCXX-INSTALL: "-L[[SYSROOT]]/usr/bin/../lib"
+//
 // Test a very broken version of multiarch that shipped in Ubuntu 11.04.
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     --target=i386-unknown-linux \