From b57e640f3a7775203f24190c4b13240bf6c2c7d4 Mon Sep 17 00:00:00 2001
From: Shoaib Meenai <smeenai@fb.com>
Date: Tue, 24 Oct 2017 21:19:22 +0000
Subject: [PATCH] [COFF] Add support for /WX

link.exe supports this option to convert warnings into errors, and it's
useful to support in LLD as well.

Differential Revision: https://reviews.llvm.org/D39148

llvm-svn: 316502
---
 lld/COFF/Config.h        |  1 +
 lld/COFF/DriverUtils.cpp |  3 +++
 lld/COFF/Error.cpp       |  5 +++++
 lld/COFF/Options.td      |  3 +--
 lld/test/COFF/wx.s       | 17 +++++++++++++++++
 5 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 lld/test/COFF/wx.s

diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
index 7a281b3..e6ade3b 100644
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -90,6 +90,7 @@ struct Configuration {
   uint64_t ErrorLimit = 20;
   bool Relocatable = true;
   bool Force = false;
+  bool FatalWarnings = false;
   bool Debug = false;
   bool WriteSymtab = true;
   unsigned DebugTypes = static_cast<unsigned>(DebugType::None);
diff --git a/lld/COFF/DriverUtils.cpp b/lld/COFF/DriverUtils.cpp
index a7e1b4e..a892d1a 100644
--- a/lld/COFF/DriverUtils.cpp
+++ b/lld/COFF/DriverUtils.cpp
@@ -738,6 +738,9 @@ opt::InputArgList ArgParser::parse(ArrayRef<const char *> Argv) {
     message(Msg);
   }
 
+  // Handle /WX early since it converts missing argument warnings to errors.
+  Config->FatalWarnings = Args.hasFlag(OPT_WX, OPT_WX_no, false);
+
   if (MissingCount)
     fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
diff --git a/lld/COFF/Error.cpp b/lld/COFF/Error.cpp
index 550d9b9..4b9c377 100644
--- a/lld/COFF/Error.cpp
+++ b/lld/COFF/Error.cpp
@@ -106,6 +106,11 @@ void fatal(llvm::Error &Err, const Twine &Msg) {
 }
 
 void warn(const Twine &Msg) {
+  if (Config->FatalWarnings) {
+    error(Msg);
+    return;
+  }
+
   std::lock_guard<std::mutex> Lock(Mu);
   print("warning: ", raw_ostream::MAGENTA);
   *ErrorOS << Msg << "\n";
diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
index 7ad269c..638516b 100644
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -85,6 +85,7 @@ def wholearchive_flag : F<"wholearchive">;
 def force : F<"force">,
     HelpText<"Allow undefined symbols when creating executables">;
 def force_unresolved : F<"force:unresolved">;
+defm WX : B<"WX", "Treat warnings as errors", "Don't treat warnings as errors">;
 
 defm allowbind : B<"allowbind", "Enable DLL binding (default)",
                    "Disable DLL binding">;
@@ -162,5 +163,3 @@ def tlbid : QF<"tlbid">;
 def tlbout : QF<"tlbout">;
 def verbose_all : QF<"verbose">;
 def guardsym : QF<"guardsym">;
-
-defm wx : QB<"wx">;
diff --git a/lld/test/COFF/wx.s b/lld/test/COFF/wx.s
new file mode 100644
index 0000000..3a470ed
--- /dev/null
+++ b/lld/test/COFF/wx.s
@@ -0,0 +1,17 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -triple=x86_64-windows-msvc -filetype=obj -o %t.obj %s
+# RUN: not lld-link /out:%t.exe /entry:main -notarealoption /WX %t.obj 2>&1 | \
+# RUN:   FileCheck -check-prefix=ERROR %s
+# RUN: not lld-link /out:%t.exe /entry:main -notarealoption /WX:NO /WX %t.obj 2>&1 | \
+# RUN:   FileCheck -check-prefix=ERROR %s
+# RUN: lld-link /out:%t.exe /entry:main -notarealoption /WX /WX:NO %t.obj 2>&1 | \
+# RUN:   FileCheck -check-prefix=WARNING %s
+
+# ERROR: error: ignoring unknown argument: -notarealoption
+# WARNING: warning: ignoring unknown argument: -notarealoption
+
+.text
+.global main
+main:
+	ret
-- 
2.7.4