Vary Windows toolchain selection by -fuse-ld

[kastiglione]

Summary

This change allows binutils to be used for linking with MSVC. Currently, when
using an MSVC target and -fuse-ld=bfd, the driver produces an invalid linker
invocation.

[kastiglione]

Use "link" as default when inspecting -fuse-ld=

[smeenai]

lib/Driver/Driver.cpp

3884 ↗

(On Diff #121185)

lld-link is a valid invocation for LLD as well, so I'd either add that option, change the equality option to a start check, or invert the check and check for an -fuse-ld= option starting with bfd (since we want the MSVC toolchain to be the default).

[smeenai]

Also title says -fused-ld instead of -fuse-ld

[kastiglione]

Base decision on "bfd" prefix

[kastiglione]

Inline the arg variable

cfe/trunk/lib/Driver/Driver.cpp

case llvm::Triple::Win32:
         TC = llvm::make_unique<toolchains::MinGW>(*this, Target, Args);
         break;
       case llvm::Triple::Itanium:
         TC = llvm::make_unique<toolchains::CrossWindowsToolChain>(*this, Target,
                                                                   Args);
         break;
       case llvm::Triple::MSVC:
       case llvm::Triple::UnknownEnvironment:
-        TC = llvm::make_unique<toolchains::MSVCToolChain>(*this, Target, Args);
+        if (Args.getLastArgValue(options::OPT_fuse_ld_EQ)
+                .startswith_lower("bfd"))
+          TC = llvm::make_unique<toolchains::CrossWindowsToolChain>(
+              *this, Target, Args);
+        else
+          TC =
+              llvm::make_unique<toolchains::MSVCToolChain>(*this, Target, Args);
         break;
       }
       break;
     case llvm::Triple::PS4:
       TC = llvm::make_unique<toolchains::PS4CPU>(*this, Target, Args);
       break;
     case llvm::Triple::Contiki:
       TC = llvm::make_unique<toolchains::Contiki>(*this, Target, Args);

cfe/trunk/test/Driver/fuse-ld.c

 // 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
+
+
+// RUN: %clang %s -### -fuse-ld=link \
+// RUN:     -target i686-unknown-windows-msvc 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-WINDOWS-MSVC-LINK
+// CHECK-WINDOWS-MSVC-LINK: "{{.*}}link.exe"
+// CHECK-WINDOWS-MSVC-LINK-SAME: "-out:{{.*}}"
+
+// RUN: %clang %s -### -fuse-ld=lld \
+// RUN:     -target i686-unknown-windows-msvc 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-WINDOWS-MSVC-LLD
+// CHECK-WINDOWS-MSVC-LLD: "{{.*}}lld-link"
+// CHECK-WINDOWS-MSVC-LLD-SAME: "-out:{{.*}}"
+
+// RUN: %clang %s -### -fuse-ld=lld-link \
+// RUN:     -target i686-unknown-windows-msvc 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-WINDOWS-MSVC-LLD-LINK
+// CHECK-WINDOWS-MSVC-LLD-LINK: "{{.*}}lld-link"
+// CHECK-WINDOWS-MSVC-LLD-LINK-SAME: "-out:{{.*}}"
+
+// RUN: %clang %s -### -fuse-ld=bfd \
+// RUN:     -target i686-unknown-windows-msvc \
+// RUN:     -B %S/Inputs/Windows/usr/bin 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-WINDOWS-MSVC-BFD
+// CHECK-WINDOWS-MSVC-BFD: "{{.*}}ld.bfd"
+// CHECK-WINDOWS-MSVC-BFD-SAME: "-o"