[clang-tidy] Add diagnostics level to YAML output

[DmitryPolukhin]

Summary

Also added BuildDirectory for completness and removed unused Fix.

Test Plan: check-all

[DmitryPolukhin]

@alexfh and @gribozavr2 friendly ping could you please take a look

[DmitryPolukhin]

@alexfh, @gribozavr2, @aaron.ballman - friendly ping, please take a look to this diff. It is just trivial implementation of TODO in the code.

[aaron.ballman]

clang/include/clang/Tooling/DiagnosticsYaml.h

109

Do we have to handle notes as well?

[DmitryPolukhin]

clang/include/clang/Tooling/DiagnosticsYaml.h

109

clang::tooling::Diagnostic::Level supports only 2 levels error and warning:
https://github.com/llvm/llvm-project/blob/master/clang/include/clang/Tooling/Core/Diagnostic.h#L65

[aaron.ballman]

LGTM!

clang/include/clang/Tooling/DiagnosticsYaml.h

109

Huh, good to know!

[DmitryPolukhin]

@aaron.ballman thank you for review and quick response!

clang-tools-extra/test/clang-tidy/infrastructure/export-diagnostics.cpp

 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t-input.cpp
-// RUN: clang-tidy %t-input.cpp -checks='-*,google-explicit-constructor,clang-diagnostic-missing-prototypes' -export-fixes=%t.yaml -- -Wmissing-prototypes > %t.msg 2>&1
+// RUN: not clang-tidy %t-input.cpp -checks='-*,google-explicit-constructor,clang-diagnostic-missing-prototypes' -export-fixes=%t.yaml -- -Wmissing-prototypes > %t.msg 2>&1
 // RUN: FileCheck -input-file=%t.msg -check-prefix=CHECK-MESSAGES %s -implicit-check-not='{{warning|error|note}}:'
 // RUN: FileCheck -input-file=%t.yaml -check-prefix=CHECK-YAML %s
 #define X(n) void n ## n() {}
 X(f)
+int a[-1];
 
 // CHECK-MESSAGES: -input.cpp:2:1: warning: no previous prototype for function 'ff' [clang-diagnostic-missing-prototypes]
 // CHECK-MESSAGES: -input.cpp:1:19: note: expanded from macro 'X'
 // CHECK-MESSAGES: {{^}}note: expanded from here{{$}}
 // CHECK-MESSAGES: -input.cpp:2:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
 // CHECK-MESSAGES: -input.cpp:1:14: note: expanded from macro 'X'
+// CHECK-MESSAGES: -input.cpp:3:7: error: 'a' declared as an array with a negative size [clang-diagnostic-error]
 
 // CHECK-YAML: ---
 // CHECK-YAML-NEXT: MainSourceFile:  '{{.*}}-input.cpp'
 // CHECK-YAML-NEXT: Diagnostics:
 // CHECK-YAML-NEXT:   - DiagnosticName:  clang-diagnostic-missing-prototypes
 // CHECK-YAML-NEXT:     DiagnosticMessage:
 // CHECK-YAML-NEXT:       Message:         'no previous prototype for function
 // ''ff'''

 // CHECK-YAML-NEXT:           - FilePath:        '{{.*}}-input.cpp'
 // CHECK-YAML-NEXT:             Offset:          30
 // CHECK-YAML-NEXT:             Length:          0
 // CHECK-YAML-NEXT:             ReplacementText: 'static '
 // CHECK-YAML-NEXT:       - Message:         'expanded from macro ''X'''
 // CHECK-YAML-NEXT:         FilePath:        '{{.*}}-input.cpp'
 // CHECK-YAML-NEXT:         FileOffset:      13
 // CHECK-YAML-NEXT:         Replacements:    []
+// CHECK-YAML-NEXT:     Level:           Warning
+// CHECK-YAML-NEXT:     BuildDirectory:  '{{.*}}'
+// CHECK-YAML-NEXT:   - DiagnosticName:  clang-diagnostic-error
+// CHECK-YAML-NEXT:     DiagnosticMessage:
+// CHECK-YAML-NEXT:       Message:         '''a'' declared as an array with a negative size'
+// CHECK-YAML-NEXT:       FilePath:        '{{.*}}-input.cpp'
+// CHECK-YAML-NEXT:       FileOffset:      41
+// CHECK-YAML-NEXT:       Replacements:    []
+// CHECK-YAML-NEXT:     Level:           Error
+// CHECK-YAML-NEXT:     BuildDirectory:  '{{.*}}'
+// CHECK-YAML-NEXT:     Ranges:
+// CHECK-YAML-NEXT:      - FilePath:        '{{.*}}-input.cpp'
+// CHECK-YAML-NEXT:         FileOffset:      41
+// CHECK-YAML-NEXT:         Length:          1
 // CHECK-YAML-NEXT: ...

clang/include/clang/Tooling/DiagnosticsYaml.h

public:
 
     clang::tooling::Diagnostic denormalize(const IO &) {
       return clang::tooling::Diagnostic(DiagnosticName, Message, Notes,
                                         DiagLevel, BuildDirectory, Ranges);
     }
 
     std::string DiagnosticName;
     clang::tooling::DiagnosticMessage Message;
-    llvm::StringMap<clang::tooling::Replacements> Fix;
     SmallVector<clang::tooling::DiagnosticMessage, 1> Notes;
     clang::tooling::Diagnostic::Level DiagLevel;
     std::string BuildDirectory;
     SmallVector<clang::tooling::FileByteRange, 1> Ranges;
   };
 
   static void mapping(IO &Io, clang::tooling::Diagnostic &D) {
     MappingNormalization<NormalizedDiagnostic, clang::tooling::Diagnostic> Keys(
         Io, D);
     Io.mapRequired("DiagnosticName", Keys->DiagnosticName);
     Io.mapRequired("DiagnosticMessage", Keys->Message);
     Io.mapOptional("Notes", Keys->Notes);
+    Io.mapOptional("Level", Keys->DiagLevel);
+    Io.mapOptional("BuildDirectory", Keys->BuildDirectory);
     Io.mapOptional("Ranges", Keys->Ranges);
-
-    // FIXME: Export properly all the different fields.
   }
 };
 
 /// Specialized MappingTraits to describe how a
 /// TranslationUnitDiagnostics is (de)serialized.
 template <> struct MappingTraits<clang::tooling::TranslationUnitDiagnostics> {
   static void mapping(IO &Io, clang::tooling::TranslationUnitDiagnostics &Doc) {
     Io.mapRequired("MainSourceFile", Doc.MainSourceFile);
     Io.mapRequired("Diagnostics", Doc.Diagnostics);
   }
 };
+
+template <> struct ScalarEnumerationTraits<clang::tooling::Diagnostic::Level> {
+  static void enumeration(IO &IO, clang::tooling::Diagnostic::Level &Value) {
+    IO.enumCase(Value, "Warning", clang::tooling::Diagnostic::Warning);
+    IO.enumCase(Value, "Error", clang::tooling::Diagnostic::Error);
+  }
+};
+
 } // end namespace yaml
 } // end namespace llvm
 
 #endif // LLVM_CLANG_TOOLING_DIAGNOSTICSYAML_H

clang/unittests/Tooling/DiagnosticsYamlTest.cpp

static const char *YAMLContent =
     "      Message:         'message #1'\n"
     "      FilePath:        'path/to/source.cpp'\n"
     "      FileOffset:      55\n"
     "      Replacements:\n"
     "        - FilePath:        'path/to/source.cpp'\n"
     "          Offset:          100\n"
     "          Length:          12\n"
     "          ReplacementText: 'replacement #1'\n"
+    "    Level:           Warning\n"
+    "    BuildDirectory:  'path/to/build/directory'\n"
     "  - DiagnosticName:  'diagnostic#2'\n"
     "    DiagnosticMessage:\n"
     "      Message:         'message #2'\n"
     "      FilePath:        'path/to/header.h'\n"
     "      FileOffset:      60\n"
     "      Replacements:\n"
     "        - FilePath:        'path/to/header.h'\n"
     "          Offset:          62\n"
     "          Length:          2\n"
     "          ReplacementText: 'replacement #2'\n"
+    "    Level:           Warning\n"
+    "    BuildDirectory:  'path/to/build/directory'\n"
     "    Ranges:\n"
     "      - FilePath:        'path/to/source.cpp'\n"
     "        FileOffset:      10\n"
     "        Length:          10\n"
     "  - DiagnosticName:  'diagnostic#3'\n"
     "    DiagnosticMessage:\n"
     "      Message:         'message #3'\n"
     "      FilePath:        'path/to/source2.cpp'\n"
     "      FileOffset:      72\n"
     "      Replacements:    []\n"
     "    Notes:\n"
     "      - Message:         Note1\n"
     "        FilePath:        'path/to/note1.cpp'\n"
     "        FileOffset:      88\n"
     "        Replacements:    []\n"
     "      - Message:         Note2\n"
     "        FilePath:        'path/to/note2.cpp'\n"
     "        FileOffset:      99\n"
     "        Replacements:    []\n"
+    "    Level:           Warning\n"
+    "    BuildDirectory:  'path/to/build/directory'\n"
     "...\n";
 
 TEST(DiagnosticsYamlTest, serializesDiagnostics) {
   TranslationUnitDiagnostics TUD;
   TUD.MainSourceFile = "path/to/source.cpp";
 
   StringMap<Replacements> Fix1 = {
       {"path/to/source.cpp",