From 73c00d40bd49ae022f6fbba7200f05facb533e3b Mon Sep 17 00:00:00 2001
From: Kadir Cetinkaya <kadircet@google.com>
Date: Tue, 7 Sep 2021 15:15:21 +0200
Subject: [PATCH] [clang][Driver] Pick the last --driver-mode in case of
 multiple ones

This was an accidental behaviour change in D106789 and this patch
restores it back to original state.

Differential Revision: https://reviews.llvm.org/D109361
---
 clang/lib/Driver/Driver.cpp              | 1 -
 clang/unittests/Driver/ToolChainTest.cpp | 7 +++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 4b56a97da717..a92b6e8c0908 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -5569,7 +5569,6 @@ llvm::StringRef clang::driver::getDriverMode(StringRef ProgName,
     if (!Arg.startswith(OptName))
       continue;
     Opt = Arg;
-    break;
   }
   if (Opt.empty())
     Opt = ToolChain::getTargetAndModeFromProgramName(ProgName).DriverMode;
diff --git a/clang/unittests/Driver/ToolChainTest.cpp b/clang/unittests/Driver/ToolChainTest.cpp
index 253c65d0e29f..f11747295778 100644
--- a/clang/unittests/Driver/ToolChainTest.cpp
+++ b/clang/unittests/Driver/ToolChainTest.cpp
@@ -16,6 +16,7 @@
 #include "clang/Basic/LLVM.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/VirtualFileSystem.h"
@@ -357,4 +358,10 @@ TEST(ToolChainTest, PostCallback) {
   EXPECT_TRUE(CallbackHasCalled);
 }
 
+TEST(GetDriverMode, PrefersLastDriverMode) {
+  static constexpr const char *Args[] = {"clang-cl", "--driver-mode=foo",
+                                         "--driver-mode=bar", "foo.cpp"};
+  EXPECT_EQ(getDriverMode(Args[0], llvm::makeArrayRef(Args).slice(1)), "bar");
+}
+
 } // end anonymous namespace.