path: root/sys-devel/llvm/files/3.9.1/clang/gcc-config.patch

From a0b8bc9ef667ed7158400f7cbf772e470661d203 Mon Sep 17 00:00:00 2001
From: Michal Gorny <mgorny@gentoo.org>
Date: Tue, 25 Oct 2016 15:07:41 +0000
Subject: [PATCH] (squashed gcc-config patch, from commits:)

[Driver] Support obtaining active toolchain from gcc-config on Gentoo

Support using gcc-config to determine the correct GCC toolchain location
on Gentoo. In order to do that, attempt to read gcc-config configuration
form [[sysroot]]/etc/env.d/gcc, if no custom toolchain location is
provided.

Differential Revision: https://reviews.llvm.org/D25661

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@285074 91177308-0d34-0410-b5e6-96231b3b80d8

[Driver] Fix finding multilib gcc install on Gentoo (with gcc-config)

Fix the gcc-config code to support multilib gcc installs properly. This
solves two problems: -mx32 using the 64-bit gcc directory (due to matching
installation triple), and -m32 not respecting gcc-config at all (due to
mismatched installation triple).

In order to fix the former issue, split the multilib scan out of
Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple() (the code
is otherwise unchanged), and call it for each installation found via
gcc-config.

In order to fix the latter issue, split the gcc-config processing out of
Generic_GCC::GCCInstallationDetector::init() and repeat it for all
triples, including extra and biarch triples. The only change
in the gcc-config code itself is adding the call to multilib scan.

Convert the gentoo_linux_gcc_multi_version_tree test input to multilib
x86_64+32+x32 install, and add appropriate tests to linux-header-search
and linux-ld.

Differential Revision: https://reviews.llvm.org/D26887

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289436 91177308-0d34-0410-b5e6-96231b3b80d8

[Driver] Attempt to fix new linux-ld tests on Windows

(broken by r289436)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289440 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/ToolChains.cpp                          | 104 +++++++++++++++++----
 lib/Driver/ToolChains.h                            |  10 ++
 .../etc/env.d/gcc/config-x86_64-pc-linux-gnu       |   1 +
 .../etc/env.d/gcc/x86_64-pc-linux-gnu-4.9.3        |  10 ++
 .../etc/gentoo-release                             |   1 +
 .../usr/include/.keep                              |   0
 .../gcc/x86_64-pc-linux-gnu/4.9.3/32/crtbegin.o    |   0
 .../lib/gcc/x86_64-pc-linux-gnu/4.9.3/crtbegin.o   |   0
 .../4.9.3/include/g++-v4.9.3/.keep                 |   0
 .../gcc/x86_64-pc-linux-gnu/4.9.3/x32/crtbegin.o   |   0
 .../gcc/x86_64-pc-linux-gnu/5.4.0/32/crtbegin.o    |   0
 .../lib/gcc/x86_64-pc-linux-gnu/5.4.0/crtbegin.o   |   0
 .../5.4.0/include/g++-v5.4.0/.keep                 |   0
 .../gcc/x86_64-pc-linux-gnu/5.4.0/x32/crtbegin.o   |   0
 .../usr/x86_64-pc-linux-gnu/lib/.keep              |   0
 test/Driver/linux-header-search.cpp                |  42 +++++++++
 test/Driver/linux-ld.c                             |  53 +++++++++++
 17 files changed, 204 insertions(+), 17 deletions(-)
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/config-x86_64-pc-linux-gnu
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/x86_64-pc-linux-gnu-4.9.3
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/gentoo-release
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/include/.keep
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/.keep
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/x32/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/32/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/include/g++-v5.4.0/.keep
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/x32/crtbegin.o
 create mode 100644 test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/x86_64-pc-linux-gnu/lib/.keep

diff --git a/tools/clang/lib/Driver/ToolChains.cpp b/tools/clang/lib/Driver/ToolChains.cpp
index 1b02f467c1..84123ea132 100644
--- a/tools/clang/lib/Driver/ToolChains.cpp
+++ b/tools/clang/lib/Driver/ToolChains.cpp
@@ -1420,6 +1420,25 @@ void Generic_GCC::GCCInstallationDetector::init(
     }
   }
 
+  // Try to respect gcc-config on Gentoo. However, do that only
+  // if --gcc-toolchain is not provided or equal to the Gentoo install
+  // in /usr. This avoids accidentally enforcing the system GCC version
+  // when using a custom toolchain.
+  if (GCCToolchainDir == "" || GCCToolchainDir == D.SysRoot + "/usr") {
+    for (StringRef CandidateTriple : ExtraTripleAliases) {
+      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple))
+        return;
+    }
+    for (StringRef CandidateTriple : CandidateTripleAliases) {
+      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple))
+        return;
+    }
+    for (StringRef CandidateTriple : CandidateBiarchTripleAliases) {
+      if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple, true))
+        return;
+    }
+  }
+
   // Loop over the various components which exist and select the best GCC
   // installation available. GCC installs are ranked by version number.
   Version = GCCVersion::Parse("0.0.0");
@@ -2546,6 +2565,33 @@ void Generic_GCC::GCCInstallationDetector::scanLibDirForGCCTripleSolaris(
   }
 }
 
+bool Generic_GCC::GCCInstallationDetector::ScanGCCForMultilibs(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    StringRef Path, bool NeedsBiarchSuffix) {
+  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
+  DetectedMultilibs Detected;
+
+  // Android standalone toolchain could have multilibs for ARM and Thumb.
+  // Debian mips multilibs behave more like the rest of the biarch ones,
+  // so handle them there
+  if (isArmOrThumbArch(TargetArch) && TargetTriple.isAndroid()) {
+    // It should also work without multilibs in a simplified toolchain.
+    findAndroidArmMultilibs(D, TargetTriple, Path, Args, Detected);
+  } else if (isMipsArch(TargetArch)) {
+    if (!findMIPSMultilibs(D, TargetTriple, Path, Args, Detected))
+      return false;
+  } else if (!findBiarchMultilibs(D, TargetTriple, Path, Args,
+                                  NeedsBiarchSuffix, Detected)) {
+    return false;
+  }
+
+  Multilibs = Detected.Multilibs;
+  SelectedMultilib = Detected.SelectedMultilib;
+  BiarchSibling = Detected.BiarchSibling;
+
+  return true;
+}
+
 void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
     const llvm::Triple &TargetTriple, const ArgList &Args,
     const std::string &LibDir, StringRef CandidateTriple,
@@ -2601,25 +2647,10 @@ void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
       if (CandidateVersion <= Version)
         continue;
 
-      DetectedMultilibs Detected;
-
-      // Android standalone toolchain could have multilibs for ARM and Thumb.
-      // Debian mips multilibs behave more like the rest of the biarch ones,
-      // so handle them there
-      if (isArmOrThumbArch(TargetArch) && TargetTriple.isAndroid()) {
-        // It should also work without multilibs in a simplified toolchain.
-        findAndroidArmMultilibs(D, TargetTriple, LI->getName(), Args, Detected);
-      } else if (isMipsArch(TargetArch)) {
-        if (!findMIPSMultilibs(D, TargetTriple, LI->getName(), Args, Detected))
-          continue;
-      } else if (!findBiarchMultilibs(D, TargetTriple, LI->getName(), Args,
-                                      NeedsBiarchSuffix, Detected)) {
+      if (!ScanGCCForMultilibs(TargetTriple, Args, LI->getName(),
+                               NeedsBiarchSuffix))
         continue;
-      }
 
-      Multilibs = Detected.Multilibs;
-      SelectedMultilib = Detected.SelectedMultilib;
-      BiarchSibling = Detected.BiarchSibling;
       Version = CandidateVersion;
       GCCTriple.setTriple(CandidateTriple);
       // FIXME: We hack together the directory name here instead of
@@ -2633,6 +2664,45 @@ void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
   }
 }
 
+bool Generic_GCC::GCCInstallationDetector::ScanGentooGccConfig(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    StringRef CandidateTriple, bool NeedsBiarchSuffix) {
+  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
+      D.getVFS().getBufferForFile(D.SysRoot + "/etc/env.d/gcc/config-" +
+                                  CandidateTriple.str());
+  if (File) {
+    SmallVector<StringRef, 2> Lines;
+    File.get()->getBuffer().split(Lines, "\n");
+    for (StringRef Line : Lines) {
+      // CURRENT=triple-version
+      if (Line.startswith("CURRENT=")) {
+        const std::pair<StringRef, StringRef> ActiveVersion =
+          Line.substr(8).rsplit('-');
+        // Note: Strictly speaking, we should be reading
+        // /etc/env.d/gcc/${CURRENT} now. However, the file doesn't
+        // contain anything new or especially useful to us.
+        const std::string GentooPath = D.SysRoot + "/usr/lib/gcc/" +
+                                       ActiveVersion.first.str() + "/" +
+                                       ActiveVersion.second.str();
+        if (D.getVFS().exists(GentooPath + "/crtbegin.o")) {
+          if (!ScanGCCForMultilibs(TargetTriple, Args, GentooPath,
+                                   NeedsBiarchSuffix))
+            return false;
+
+          Version = GCCVersion::Parse(ActiveVersion.second);
+          GCCInstallPath = GentooPath;
+          GCCParentLibPath = GentooPath + "/../../..";
+          GCCTriple.setTriple(ActiveVersion.first);
+          IsValid = true;
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
 Generic_GCC::Generic_GCC(const Driver &D, const llvm::Triple &Triple,
                          const ArgList &Args)
     : ToolChain(D, Triple, Args), GCCInstallation(D), CudaInstallation(D) {
diff --git a/tools/clang/lib/Driver/ToolChains.h b/tools/clang/lib/Driver/ToolChains.h
index 369712fa93..6c2d0cb201 100644
--- a/tools/clang/lib/Driver/ToolChains.h
+++ b/tools/clang/lib/Driver/ToolChains.h
@@ -143,6 +143,11 @@ public:
                              SmallVectorImpl<StringRef> &BiarchLibDirs,
                              SmallVectorImpl<StringRef> &BiarchTripleAliases);
 
+    bool ScanGCCForMultilibs(const llvm::Triple &TargetTriple,
+                             const llvm::opt::ArgList &Args,
+                             StringRef Path,
+                             bool NeedsBiarchSuffix = false);
+
     void ScanLibDirForGCCTriple(const llvm::Triple &TargetArch,
                                 const llvm::opt::ArgList &Args,
                                 const std::string &LibDir,
@@ -154,6 +159,11 @@ public:
                                        const std::string &LibDir,
                                        StringRef CandidateTriple,
                                        bool NeedsBiarchSuffix = false);
+
+    bool ScanGentooGccConfig(const llvm::Triple &TargetTriple,
+                             const llvm::opt::ArgList &Args,
+                             StringRef CandidateTriple,
+                             bool NeedsBiarchSuffix = false);
   };
 
 protected:
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/config-x86_64-pc-linux-gnu b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/config-x86_64-pc-linux-gnu
new file mode 100644
index 0000000000..5ef56a33a6
--- /dev/null
+++ b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/config-x86_64-pc-linux-gnu
@@ -0,0 +1 @@
+CURRENT=x86_64-pc-linux-gnu-4.9.3
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/x86_64-pc-linux-gnu-4.9.3 b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/x86_64-pc-linux-gnu-4.9.3
new file mode 100644
index 0000000000..9ff406284f
--- /dev/null
+++ b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/env.d/gcc/x86_64-pc-linux-gnu-4.9.3
@@ -0,0 +1,10 @@
+PATH="/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.3"
+ROOTPATH="/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.3"
+GCC_PATH="/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.3"
+LDPATH="/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3:/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32"
+MANPATH="/usr/share/gcc-data/x86_64-pc-linux-gnu/4.9.3/man"
+INFOPATH="/usr/share/gcc-data/x86_64-pc-linux-gnu/4.9.3/info"
+STDCXX_INCDIR="g++-v4"
+CTARGET="x86_64-pc-linux-gnu"
+GCC_SPECS=""
+MULTIOSDIRS="../lib64:../lib32"
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/gentoo-release b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/gentoo-release
new file mode 100644
index 0000000000..5f0944f7d9
--- /dev/null
+++ b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/etc/gentoo-release
@@ -0,0 +1 @@
+Gentoo Base System release 2.3
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/include/.keep b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/include/.keep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/.keep b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/.keep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/x32/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/x32/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/32/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/32/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/include/g++-v5.4.0/.keep b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/include/g++-v5.4.0/.keep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/x32/crtbegin.o b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/lib/gcc/x86_64-pc-linux-gnu/5.4.0/x32/crtbegin.o
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/x86_64-pc-linux-gnu/lib/.keep b/tools/clang/test/Driver/Inputs/gentoo_linux_gcc_multi_version_tree/usr/x86_64-pc-linux-gnu/lib/.keep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tools/clang/test/Driver/linux-header-search.cpp b/tools/clang/test/Driver/linux-header-search.cpp
index 5f6ac504a0..274895fb4f 100644
--- a/tools/clang/test/Driver/linux-header-search.cpp
+++ b/tools/clang/test/Driver/linux-header-search.cpp
@@ -301,6 +301,48 @@
 // CHECK-GENTOO-4-9-3: "-internal-externc-isystem" "[[SYSROOT]]/include"
 // CHECK-GENTOO-4-9-3: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
 //
+// Test support for Gentoo's gcc-config -- clang should prefer the older
+// (4.9.3) version over the newer (5.4.0) due to preference specified
+// in /etc/env.d/gcc/x86_64-pc-linux-gnu.
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
+// RUN:     -target x86_64-unknown-linux-gnu -stdlib=libstdc++ \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-GENTOO-4-9-3 %s
+//
+// Test that gcc-config support does not break multilib.
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
+// RUN:     -target x86_64-unknown-linux-gnux32 -stdlib=libstdc++ \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-GENTOO-4-9-3-X32 %s
+// CHECK-GENTOO-4-9-3-X32: "{{.*}}clang{{.*}}" "-cc1"
+// CHECK-GENTOO-4-9-3-X32: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-GENTOO-4-9-3-X32: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-GENTOO-4-9-3-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3"
+// CHECK-GENTOO-4-9-3-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/x86_64-pc-linux-gnu/x32"
+// CHECK-GENTOO-4-9-3-X32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/backward"
+// CHECK-GENTOO-4-9-3-X32: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-GENTOO-4-9-3-X32: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-GENTOO-4-9-3-X32: "-internal-externc-isystem" "[[SYSROOT]]/include"
+// CHECK-GENTOO-4-9-3-X32: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
+//
+// RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
+// RUN:     -target i386-unknown-linux-gnu -stdlib=libstdc++ \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-GENTOO-4-9-3-32 %s
+// CHECK-GENTOO-4-9-3-32: "{{.*}}clang{{.*}}" "-cc1"
+// CHECK-GENTOO-4-9-3-32: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-GENTOO-4-9-3-32: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-GENTOO-4-9-3-32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3"
+// CHECK-GENTOO-4-9-3-32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/x86_64-pc-linux-gnu/32"
+// CHECK-GENTOO-4-9-3-32: "-internal-isystem" "[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/include/g++-v4.9.3/backward"
+// CHECK-GENTOO-4-9-3-32: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-GENTOO-4-9-3-32: "-internal-isystem" "[[RESOURCE_DIR]]{{/|\\\\}}include"
+// CHECK-GENTOO-4-9-3-32: "-internal-externc-isystem" "[[SYSROOT]]/include"
+// CHECK-GENTOO-4-9-3-32: "-internal-externc-isystem" "[[SYSROOT]]/usr/include"
+//
 // Check header search on Debian 6 / MIPS64
 // RUN: %clang -no-canonical-prefixes %s -### -fsyntax-only 2>&1 \
 // RUN:     -target mips64-unknown-linux-gnuabi64 -stdlib=libstdc++ \
diff --git a/tools/clang/test/Driver/linux-ld.c b/tools/clang/test/Driver/linux-ld.c
index f9f4b482c9..ee995ac2d6 100644
--- a/tools/clang/test/Driver/linux-ld.c
+++ b/tools/clang/test/Driver/linux-ld.c
@@ -1650,3 +1650,56 @@
 // CHECK-MUSL-ARMEBHF:    "-dynamic-linker" "/lib/ld-musl-armebhf.so.1"
 // CHECK-MUSL-AARCH64:    "-dynamic-linker" "/lib/ld-musl-aarch64.so.1"
 // CHECK-MUSL-AARCH64_BE: "-dynamic-linker" "/lib/ld-musl-aarch64_be.so.1"
+
+// Check whether multilib gcc install works fine on Gentoo with gcc-config
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-unknown-linux-gnu -rtlib=platform \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-GENTOO %s
+// CHECK-LD-GENTOO-NOT: warning:
+// CHECK-LD-GENTOO: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-LD-GENTOO: "--eh-frame-hdr"
+// CHECK-LD-GENTOO: "-m" "elf_x86_64"
+// CHECK-LD-GENTOO: "-dynamic-linker"
+// CHECK-LD-GENTOO: "{{.*}}/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3{{/|\\\\}}crtbegin.o"
+// CHECK-LD-GENTOO: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3"
+// CHECK-LD-GENTOO: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../../../x86_64-pc-linux-gnu/lib"
+// CHECK-LD-GENTOO: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../.."
+// CHECK-LD-GENTOO: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// CHECK-LD-GENTOO: "-lc"
+// CHECK-LD-GENTOO: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=i686-unknown-linux-gnu -rtlib=platform \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-GENTOO-32 %s
+// CHECK-LD-GENTOO-32-NOT: warning:
+// CHECK-LD-GENTOO-32: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-LD-GENTOO-32: "--eh-frame-hdr"
+// CHECK-LD-GENTOO-32: "-m" "elf_i386"
+// CHECK-LD-GENTOO-32: "-dynamic-linker"
+// CHECK-LD-GENTOO-32: "{{.*}}/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32{{/|\\\\}}crtbegin.o"
+// CHECK-LD-GENTOO-32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/32"
+// CHECK-LD-GENTOO-32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../../../x86_64-pc-linux-gnu/lib"
+// CHECK-LD-GENTOO-32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../.."
+// CHECK-LD-GENTOO-32: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// CHECK-LD-GENTOO-32: "-lc"
+// CHECK-LD-GENTOO-32: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-unknown-linux-gnux32 -rtlib=platform \
+// RUN:     --sysroot=%S/Inputs/gentoo_linux_gcc_multi_version_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-LD-GENTOO-X32 %s
+// CHECK-LD-GENTOO-X32-NOT: warning:
+// CHECK-LD-GENTOO-X32: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-LD-GENTOO-X32: "--eh-frame-hdr"
+// CHECK-LD-GENTOO-X32: "-m" "elf32_x86_64"
+// CHECK-LD-GENTOO-X32: "-dynamic-linker"
+// CHECK-LD-GENTOO-X32: "{{.*}}/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/x32{{/|\\\\}}crtbegin.o"
+// CHECK-LD-GENTOO-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/x32"
+// CHECK-LD-GENTOO-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../../../x86_64-pc-linux-gnu/lib"
+// CHECK-LD-GENTOO-X32: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../.."
+// CHECK-LD-GENTOO-X32: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// CHECK-LD-GENTOO-X32: "-lc"
+// CHECK-LD-GENTOO-X32: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
-- 
2.11.0