[Driver] Set the default driver mode based on the executable.

Currently, if --driver-mode is not passed at all, it will default
to GCC style driver.  This is never an issue for clang because
it manually constructs a --driver-mode option and passes it.

However, we should still try to do as good as we can even if no
--driver-mode is passed.  LibTooling, for example, does not pass
a --driver-mode option and while it could, it seems like we should
still fallback to the best possible default we can.

This is one of two steps necessary to get clang-tidy working on Windows.

Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D23454

llvm-svn: 278535

1 files changed, 25 insertions, 0 deletions

diff --git a/clang/unittests/Driver/ToolChainTest.cpp b/clang/unittests/Driver/ToolChainTest.cpp
index ef21e2d17c6..f7ba3eeab21 100644
--- a/clang/unittests/Driver/ToolChainTest.cpp
+++ b/clang/unittests/Driver/ToolChainTest.cpp
@@ -117,4 +117,29 @@ TEST(ToolChainTest, VFSGCCInstallationRelativeDir) {
             S);
 }
 
+TEST(ToolChainTest, DefaultDriverMode) {
+  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
+
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  struct TestDiagnosticConsumer : public DiagnosticConsumer {};
+  DiagnosticsEngine Diags(DiagID, &*DiagOpts, new TestDiagnosticConsumer);
+  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new vfs::InMemoryFileSystem);
+
+  Driver CCDriver("/home/test/bin/clang", "arm-linux-gnueabi", Diags,
+                  InMemoryFileSystem);
+  Driver CXXDriver("/home/test/bin/clang++", "arm-linux-gnueabi", Diags,
+                   InMemoryFileSystem);
+  Driver CLDriver("/home/test/bin/clang-cl", "arm-linux-gnueabi", Diags,
+                  InMemoryFileSystem);
+
+  std::unique_ptr<Compilation> CC(CCDriver.BuildCompilation({"foo.cpp"}));
+  std::unique_ptr<Compilation> CXX(CXXDriver.BuildCompilation({"foo.cpp"}));
+  std::unique_ptr<Compilation> CL(CLDriver.BuildCompilation({"foo.cpp"}));
+
+  EXPECT_TRUE(CCDriver.CCCIsCC());
+  EXPECT_TRUE(CXXDriver.CCCIsCXX());
+  EXPECT_TRUE(CLDriver.IsCLMode());
+}
+
 } // end anonymous namespace