Make a good guess about where MSVC and Windows SDK libraries are for linking.

When a user has not configured a standard Visual Studio environment
by running vcvarsall, clang tries its best to find Visual Studio
include files and executables anyway.  This patch makes clang also
try to find system and Windows SDK libraries for linking against,
as well.

Reviewed by: Hans Wennborg
Differential Revision: http://reviews.llvm.org/D5873

llvm-svn: 220425

1 files changed, 33 insertions, 0 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 1c0a6ff..6e7060f 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -7854,6 +7854,39 @@ void visualstudio::Link::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-defaultlib:libcmt");
   }
 
+  if (!llvm::sys::Process::GetEnv("LIB")) {
+    // If the VC environment hasn't been configured (perhaps because the user
+    // did not run vcvarsall), try to build a consistent link environment.  If
+    // the environment variable is set however, assume the user knows what he's
+    // doing.
+    std::string VisualStudioDir;
+    const auto &MSVC = static_cast<const toolchains::MSVCToolChain &>(getToolChain());
+    if (MSVC.getVisualStudioInstallDir(VisualStudioDir)) {
+      SmallString<128> LibDir(VisualStudioDir);
+      llvm::sys::path::append(LibDir, "VC", "lib");
+      switch (MSVC.getArch()) {
+      case llvm::Triple::x86:
+        // x86 just puts the libraries directly in lib
+        break;
+      case llvm::Triple::x86_64:
+        llvm::sys::path::append(LibDir, "amd64");
+        break;
+      case llvm::Triple::arm:
+        llvm::sys::path::append(LibDir, "arm");
+        break;
+      default:
+        break;
+      }
+      CmdArgs.push_back(
+          Args.MakeArgString(std::string("-libpath:") + LibDir.c_str()));
+    }
+
+    std::string WindowsSdkLibPath;
+    if (MSVC.getWindowsSDKLibraryPath(WindowsSdkLibPath))
+      CmdArgs.push_back(Args.MakeArgString(std::string("-libpath:") +
+                                           WindowsSdkLibPath.c_str()));
+  }
+
   CmdArgs.push_back("-nologo");
 
   if (Args.hasArg(options::OPT_g_Group)) {