Implement the -fuse-ld= option.

This commit implements the -fuse-ld= option, so that the user
can specify -fuse-ld=bfd to use ld.bfd.

This commit re-applies r194328 with some test case changes.
It seems that r194328 was breaking macosx or mingw build
because clang can't find ld.bfd or ld.gold in the given sysroot.
We should use -B to specify the executable search path instead.

Patch originally by David Chisnall.

llvm-svn: 211785

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -22,6 +22,8 @@ def err_drv_unknown_stdin_type_clang_cl : Error<
 def err_drv_unknown_language : Error<"language not recognized: '%0'">;
 def err_drv_invalid_arch_name : Error<
   "invalid arch name '%0'">;
+def err_drv_invalid_linker_name : Error<
+  "invalid linker name in argument '%0'">;
 def err_drv_invalid_rtlib_name : Error<
   "invalid runtime library name in argument '%0'">;
 def err_drv_unsupported_rtlib_for_platform : Error<

clang/include/clang/Driver/Options.td

@@ -1542,7 +1542,7 @@ def fprofile_dir : Joined<["-"], "fprofile-dir=">, Group<clang_ignored_f_Group>;
 
 defm profile_use : BooleanFFlag<"profile-use">, Group<clang_ignored_f_Group>;
 def fprofile_use_EQ : Joined<["-"], "fprofile-use=">, Group<clang_ignored_f_Group>;
-def fuse_ld_EQ : Joined<["-"], "fuse-ld=">, Group<clang_ignored_f_Group>;
+def fuse_ld_EQ : Joined<["-"], "fuse-ld=">, Group<f_Group>;
 
 defm align_functions : BooleanFFlag<"align-functions">, Group<clang_ignored_f_Group>;
 def falign_functions_EQ : Joined<["-"], "falign-functions=">, Group<clang_ignored_f_Group>;

clang/include/clang/Driver/ToolChain.h

@@ -158,6 +158,10 @@ public:
   std::string GetFilePath(const char *Name) const;
   std::string GetProgramPath(const char *Name) const;
 
+  /// Returns the linker path, respecting the -fuse-ld= argument to determine
+  /// the linker suffix or name.
+  std::string GetLinkerPath() const;
+
   /// \brief Dispatch to the specific toolchain for verbose printing.
   ///
   /// This is used when handling the verbose option to print detailed,

clang/lib/Driver/ToolChain.cpp

@@ -15,6 +15,7 @@
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
 #include "clang/Driver/ToolChain.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
@@ -147,6 +148,30 @@ std::string ToolChain::GetProgramPath(const char *Name) const {
   return D.GetProgramPath(Name, *this);
 }
 
+std::string ToolChain::GetLinkerPath() const {
+  if (Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
+    StringRef Suffix = A->getValue();
+
+    // If we're passed -fuse-ld= with no argument, or with the argument ld,
+    // then use whatever the default system linker is.
+    if (Suffix.empty() || Suffix == "ld")
+      return GetProgramPath("ld");
+
+    llvm::SmallString<8> LinkerName("ld.");
+    LinkerName.append(Suffix);
+
+    std::string LinkerPath(GetProgramPath(LinkerName.c_str()));
+    if (llvm::sys::fs::exists(LinkerPath))
+      return LinkerPath;
+
+    getDriver().Diag(diag::err_drv_invalid_linker_name) << A->getAsString(Args);
+    return "";
+  }
+
+  return GetProgramPath("ld");
+}
+
+
 types::ID ToolChain::LookupTypeForExtension(const char *Ext) const {
   return types::lookupTypeForExtension(Ext);
 }

clang/lib/Driver/ToolChains.cpp

@@ -3001,7 +3001,7 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
   PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
                          GCCInstallation.getTriple().str() + "/bin").str());
 
-  Linker = GetProgramPath("ld");
+  Linker = GetLinkerPath();
 
   Distro Distro = DetectDistro(Arch);
 

clang/lib/Driver/Tools.cpp

@@ -5614,7 +5614,7 @@ void darwin::Link::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddAllArgs(CmdArgs, options::OPT_F);
 
   const char *Exec =
-    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -5804,7 +5804,7 @@ void solaris::Link::ConstructJob(Compilation &C, const JobAction &JA,
   addProfileRT(getToolChain(), Args, CmdArgs);
 
   const char *Exec =
-    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -5912,7 +5912,7 @@ void auroraux::Link::ConstructJob(Compilation &C, const JobAction &JA,
   addProfileRT(getToolChain(), Args, CmdArgs);
 
   const char *Exec =
-    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -6114,7 +6114,7 @@ void openbsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   const char *Exec =
-    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -6250,7 +6250,7 @@ void bitrig::Link::ConstructJob(Compilation &C, const JobAction &JA,
   }
 
   const char *Exec =
-    Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -6514,7 +6514,7 @@ void freebsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
   addProfileRT(ToolChain, Args, CmdArgs);
 
   const char *Exec =
-    Args.MakeArgString(ToolChain.GetProgramPath("ld"));
+    Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -6767,7 +6767,7 @@ void netbsd::Link::ConstructJob(Compilation &C, const JobAction &JA,
 
   addProfileRT(getToolChain(), Args, CmdArgs);
 
-  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  const char *Exec = Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -7325,7 +7325,7 @@ void minix::Link::ConstructJob(Compilation &C, const JobAction &JA,
          Args.MakeArgString(getToolChain().GetFilePath("crtend.o")));
   }
 
-  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  const char *Exec = Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 
@@ -7503,7 +7503,7 @@ void dragonfly::Link::ConstructJob(Compilation &C, const JobAction &JA,
 
   addProfileRT(getToolChain(), Args, CmdArgs);
 
-  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("ld"));
+  const char *Exec = Args.MakeArgString(getToolChain().GetLinkerPath());
   C.addCommand(new Command(JA, *this, Exec, CmdArgs));
 }
 

clang/test/Driver/fuse-ld.c

@@ -0,0 +1,63 @@
+// RUN: %clang %s -### \
+// RUN:     -target x86_64-unknown-freebsd 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-FREEBSD-LD
+// CHECK-FREEBSD-LD: ld
+
+// RUN: %clang %s -### -fuse-ld=bfd \
+// RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
+// RUN:     -target x86_64-unknown-freebsd \
+// RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-BFD
+// CHECK-FREEBSD-BFD: Inputs/basic_freebsd_tree/usr/bin/ld.bfd
+
+// RUN: %clang %s -### -fuse-ld=gold \
+// RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
+// RUN:     -target x86_64-unknown-freebsd \
+// RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-GOLD
+// CHECK-FREEBSD-GOLD: Inputs/basic_freebsd_tree/usr/bin/ld.gold
+
+// RUN: %clang %s -### -fuse-ld=plib \
+// RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
+// RUN:     -target x86_64-unknown-freebsd \
+// RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-PLIB
+// CHECK-FREEBSD-PLIB: error: invalid linker name
+
+
+
+// RUN: %clang %s -### \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-ANDROID-ARM-LD
+// CHECK-ANDROID-ARM-LD: Inputs/basic_android_tree/bin/arm-linux-androideabi-ld
+
+// RUN: %clang %s -### -fuse-ld=bfd \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-BFD
+// CHECK-ANDROID-ARM-BFD: Inputs/basic_android_tree/bin/arm-linux-androideabi-ld.bfd
+
+// RUN: %clang %s -### -fuse-ld=gold \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-GOLD
+// CHECK-ANDROID-ARM-GOLD: Inputs/basic_android_tree/bin/arm-linux-androideabi-ld.gold
+
+// RUN: %clang %s -### \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -gcc-toolchain %S/Inputs/basic_android_tree 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-ANDROID-ARM-LD-TC
+// CHECK-ANDROID-ARM-LD-TC: Inputs/basic_android_tree/lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld
+
+// RUN: %clang %s -### -fuse-ld=bfd \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -gcc-toolchain %S/Inputs/basic_android_tree 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-BFD-TC
+// CHECK-ANDROID-ARM-BFD-TC: Inputs/basic_android_tree/lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld.bfd
+
+// RUN: %clang %s -### -fuse-ld=gold \
+// RUN:     -target arm-linux-androideabi \
+// RUN:     -gcc-toolchain %S/Inputs/basic_android_tree 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-GOLD-TC
+// CHECK-ANDROID-ARM-GOLD-TC: Inputs/basic_android_tree/lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld.gold