[YAMLTraits] Add filename support to yaml::Input

Summary:
The current yaml::Input constructor takes a StringRef of data as its
first parameter, discarding any filename information that may have been
present when a YAML file was opened. Add an alterate yaml::Input
constructor that takes a MemoryBufferRef, which can have a filename
associated with it. This leads to clearer diagnostic messages.

Sponsored By: DARPA, AFRL

Reviewed By: arphaman

Differential Revision: https://reviews.llvm.org/D35398

Patch by: Jonathan Anderson (trombonehero)

llvm-svn: 308172

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/unittests/Support/YAMLIOTest.cpp b/llvm/unittests/Support/YAMLIOTest.cpp
index 5cf0e9d0f5b..120773a0c8d 100644
--- a/llvm/unittests/Support/YAMLIOTest.cpp
+++ b/llvm/unittests/Support/YAMLIOTest.cpp
@@ -232,6 +232,22 @@ TEST(YAMLIO, TestSequenceMapWriteAndRead) {
   }
 }
 
+//
+// Test YAML filename handling.
+//
+static void testErrorFilename(const llvm::SMDiagnostic &Error, void *) {
+  EXPECT_EQ(Error.getFilename(), "foo.yaml");
+}
+
+TEST(YAMLIO, TestGivenFilename) {
+  auto Buffer = llvm::MemoryBuffer::getMemBuffer("{ x: 42 }", "foo.yaml");
+  Input yin(*Buffer, nullptr, testErrorFilename);
+  FooBar Value;
+  yin >> Value;
+
+  EXPECT_TRUE(!!yin.error());
+}
+
 
 //===----------------------------------------------------------------------===//
 //  Test built-in types