From d2ad1701f60fb85b924be04ba3c9848ceb8f51a2 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Tue, 16 Sep 2014 19:22:00 +0000
Subject: [PATCH] Fix forwarding -l to MSVC's link.exe

Translate -lfoo to -lfoo.lib while making sure that -lfoo.lib stays as
-lfoo.lib. Also, these arguments were being passed twice: once
explicitly via AddAllArgs, and again implicitly as linker inputs. Now
they are passed once.

Fixes PR20868.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217895 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/Tools.cpp       | 30 ++++++++++++++++++++++++------
 test/Driver/msvc_forward.c |  4 +++-
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 0262764591..8d9af96913 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -7825,15 +7825,33 @@ void visualstudio::Link::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
-  Args.AddAllArgValues(CmdArgs, options::OPT_l);
   Args.AddAllArgValues(CmdArgs, options::OPT__SLASH_link);
 
-  // Add filenames immediately.
-  for (const auto &Input : Inputs)
-    if (Input.isFilename())
+  // Add filenames, libraries, and other linker inputs.
+  for (const auto &Input : Inputs) {
+    if (Input.isFilename()) {
       CmdArgs.push_back(Input.getFilename());
-    else
-      Input.getInputArg().renderAsInput(Args, CmdArgs);
+      continue;
+    }
+
+    const Arg &A = Input.getInputArg();
+
+    // Render -l options differently for the MSVC linker.
+    if (A.getOption().matches(options::OPT_l)) {
+      StringRef Lib = A.getValue();
+      const char *LinkLibArg;
+      if (Lib.endswith(".lib"))
+        LinkLibArg = Args.MakeArgString(Lib);
+      else
+        LinkLibArg = Args.MakeArgString(Lib + ".lib");
+      CmdArgs.push_back(LinkLibArg);
+      continue;
+    }
+
+    // Otherwise, this is some other kind of linker input option like -Wl, -z,
+    // or -L. Render it, even if MSVC doesn't understand it.
+    A.renderAsInput(Args, CmdArgs);
+  }
 
   const char *Exec =
     Args.MakeArgString(getToolChain().GetProgramPath("link.exe"));
diff --git a/test/Driver/msvc_forward.c b/test/Driver/msvc_forward.c
index fe0ae84790..15f941ef95 100644
--- a/test/Driver/msvc_forward.c
+++ b/test/Driver/msvc_forward.c
@@ -1,5 +1,7 @@
-// RUN: %clang -target i686-pc-win32 -lkernel32.lib -luser32.lib -### %s 2>&1 | FileCheck %s
+// RUN: %clang -target i686-pc-win32 -loldnames -lkernel32.lib -luser32.lib -### %s 2>&1 | FileCheck %s
+// CHECK-NOT: "-loldnames.lib"
 // CHECK-NOT: "-lkernel32.lib"
 // CHECK-NOT: "-luser32.lib"
+// CHECK: "oldnames.lib"
 // CHECK: "kernel32.lib"
 // CHECK: "user32.lib"
-- 
2.50.1