Reland r341390 clang-cl: Pass /Brepro to linker if it was passed to t…

…he compiler

The test was missing  '--' on mac as pointed out by -Wslash-u-filename:
<stdin>:5:69: note: possible intended match here
clang: warning: '/Users/thakis/src/llvm-mono/clang/test/Driver/msvc-link.c' treated as the '/U' option [-Wslash-u-filename]

Differential Revision: https://reviews.llvm.org/D51635

llvm-svn: 341654

clang/lib/Driver/ToolChains/MSVC.cpp

@@ -355,6 +355,15 @@ void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                   options::OPT__SLASH_Zd))
     CmdArgs.push_back("-debug");
 
+  // Pass on /Brepro if it was passed to the compiler.
+  // Note that /Brepro maps to -mno-incremental-linker-compatible.
+  bool DefaultIncrementalLinkerCompatible =
+      C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment();
+  if (!Args.hasFlag(options::OPT_mincremental_linker_compatible,
+                    options::OPT_mno_incremental_linker_compatible,
+                    DefaultIncrementalLinkerCompatible))
+    CmdArgs.push_back("-Brepro");
+
   bool DLL = Args.hasArg(options::OPT__SLASH_LD, options::OPT__SLASH_LDd,
                          options::OPT_shared);
   if (DLL) {

clang/test/Driver/msvc-link.c

@@ -3,6 +3,7 @@
 // BASIC: "-out:a.exe"
 // BASIC: "-defaultlib:libcmt"
 // BASIC: "-nologo"
+// BASIC-NOT: "-Brepro"
 
 // RUN: %clang -target i686-pc-windows-msvc -shared -o a.dll -### %s 2>&1 | FileCheck --check-prefix=DLL %s
 // DLL: link.exe"
@@ -16,3 +17,14 @@
 // LIBPATH: "-libpath:/usr/lib"
 // LIBPATH: "-nologo"
 
+// RUN: %clang_cl /Brepro -### -- %s 2>&1 | FileCheck --check-prefix=REPRO %s
+// REPRO: link.exe"
+// REPRO: "-out:msvc-link.exe"
+// REPRO: "-nologo"
+// REPRO: "-Brepro"
+
+// RUN: %clang_cl /Brepro- -### -- %s 2>&1 | FileCheck --check-prefix=NOREPRO %s
+// NOREPRO: link.exe"
+// NOREPRO: "-out:msvc-link.exe"
+// NOREPRO: "-nologo"
+// NOREPRO-NOT: "-Brepro"