[YAMLParser] Support block nodes when parsing YAML strings.

[zjaffal]

Summary

Previously if a string is in the format

|
      val
      val2
      val3

Yaml parser will error out without parsing the string. The mentioned pattern is a valid yaml str and should be parsed.

[thegameg]

LGTM

[fhahn]

Great to see this fixed! LGTM, thanks!

llvm/lib/Remarks/YAMLRemarkParser.cpp

Expected<StringRef> YAMLRemarkParser::parseKey(yaml::KeyValueNode &Node) {
   if (auto *Key = dyn_cast<yaml::ScalarNode>(Node.getKey()))
     return Key->getRawValue();
 
   return error("key is not a string.", Node);
 }
 
 Expected<StringRef> YAMLRemarkParser::parseStr(yaml::KeyValueNode &Node) {
   auto *Value = dyn_cast<yaml::ScalarNode>(Node.getValue());
-  if (!Value)
+  yaml::BlockScalarNode *ValueBlock;
+  StringRef Result;
+  if (!Value) {
+    // Try to parse the value as a block node.
+    ValueBlock = dyn_cast<yaml::BlockScalarNode>(Node.getValue());
+    if (!ValueBlock)
       return error("expected a value of scalar type.", Node);
-  StringRef Result = Value->getRawValue();
+    Result = ValueBlock->getValue();
+  } else
+    Result = Value->getRawValue();
 
   if (Result.front() == '\'')
     Result = Result.drop_front();
 
   if (Result.back() == '\'')
     Result = Result.drop_back();
 
   return Result;
Expected<std::unique_ptr<Remark>> YAMLRemarkParser::next() {
 
   ++YAMLIt;
 
   return std::move(*MaybeResult);
 }
 
 Expected<StringRef> YAMLStrTabRemarkParser::parseStr(yaml::KeyValueNode &Node) {
   auto *Value = dyn_cast<yaml::ScalarNode>(Node.getValue());
-  if (!Value)
-    return error("expected a value of scalar type.", Node);
+  yaml::BlockScalarNode *ValueBlock;
   StringRef Result;
+  if (!Value) {
+    // Try to parse the value as a block node.
+    ValueBlock = dyn_cast<yaml::BlockScalarNode>(Node.getValue());
+    if (!ValueBlock)
+      return error("expected a value of scalar type.", Node);
+    Result = ValueBlock->getValue();
+  } else
+    Result = Value->getRawValue();
   // If we have a string table, parse it as an unsigned.
   unsigned StrID = 0;
   if (Expected<unsigned> MaybeStrID = parseUnsigned(Node))
     StrID = *MaybeStrID;
   else
     return MaybeStrID.takeError();
 
   if (Expected<StringRef> Str = (*StrTab)[StrID])

llvm/unittests/Remarks/YAMLRemarksParsingTest.cpp

parseGood("\n"
             "Args:\n"
             "  - Callee: bar\n"
             "  - String: ' will not be inlined into '\n"
             "  - Caller: foo\n"
             "    DebugLoc: { File: file.c, Line: 2, Column: 0 }\n"
             "  - String: ' because its definition is unavailable'\n"
             "Pass: inline\n"
             "");
+
+  // Block Remark.
+  parseGood("\n"
+            "--- !Missed\n"
+            "Function: foo\n"
+            "Name: NoDefinition\n"
+            "Args:\n"
+            "  - String:           |\n      \n      \n      blocks\n"
+            "Pass: inline\n"
+            "");
 }
 
 // Mandatory common part of a remark.
 #define COMMON_REMARK "\nPass: inline\nName: NoDefinition\nFunction: foo\n\n"
 // Test all the types.
 TEST(YAMLRemarks, ParsingTypes) {
   // Type: Passed
   parseGood("--- !Passed" COMMON_REMARK);