[Frontend] SetUpDiagnosticLog should handle unowned diagnostic consumer

in the compiler

The function SetUpDiagnosticLog that was called from createDiagnostics didn't
handle the case where the diagnostics engine didn't own the diagnostics consumer.
This is a potential problem for a clang tool, in particular some of the follow-up
patches for clang-scan-deps will need this fix.

Differential Revision: https://reviews.llvm.org/D63101

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@363009 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 0 deletions

diff --git a/unittests/Frontend/CompilerInstanceTest.cpp b/unittests/Frontend/CompilerInstanceTest.cpp
index 1c3803289b..3ef13d32ca 100644
--- a/unittests/Frontend/CompilerInstanceTest.cpp
+++ b/unittests/Frontend/CompilerInstanceTest.cpp
@@ -8,6 +8,7 @@
 
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/ToolOutputFile.h"
@@ -70,4 +71,21 @@ TEST(CompilerInstance, DefaultVFSOverlayFromInvocation) {
   ASSERT_TRUE(Instance.getFileManager().getFile("vfs-virtual.file"));
 }
 
+TEST(CompilerInstance, AllowDiagnosticLogWithUnownedDiagnosticConsumer) {
+  auto DiagOpts = new DiagnosticOptions();
+  DiagOpts->DiagnosticLogFile = "log.diags";
+
+  // Create the diagnostic engine with unowned consumer.
+  std::string DiagnosticOutput;
+  llvm::raw_string_ostream DiagnosticsOS(DiagnosticOutput);
+  auto DiagPrinter = llvm::make_unique<TextDiagnosticPrinter>(
+      DiagnosticsOS, new DiagnosticOptions());
+  CompilerInstance Instance;
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags = Instance.createDiagnostics(
+      DiagOpts, DiagPrinter.get(), /*ShouldOwnClient=*/false);
+
+  Diags->Report(diag::err_expected) << "no crash";
+  ASSERT_EQ(DiagnosticsOS.str(), "error: expected no crash\n");
+}
+
 } // anonymous namespace