[flang] First cut at parser instrumentation with pass/fail counters.

Original-commit: flang-compiler/f18@21ed700afa6b7d7ec9ee5477d7d16a01ead42557
Reviewed-on: https://github.com/flang-compiler/f18/pull/62
Tree-same-pre-rewrite: false

1 files changed, 59 insertions, 0 deletions

diff --git a/flang/lib/parser/instrumented-parser.h b/flang/lib/parser/instrumented-parser.h
new file mode 100644
index 000000000000..e4786303ac84
--- /dev/null
+++ b/flang/lib/parser/instrumented-parser.h
@@ -0,0 +1,59 @@
+#ifndef FORTRAN_PARSER_INSTRUMENTED_PARSER_H_
+#define FORTRAN_PARSER_INSTRUMENTED_PARSER_H_
+
+#include "message.h"
+#include "parse-state.h"
+#include "user-state.h"
+#include <cstddef>
+#include <map>
+#include <ostream>
+
+namespace Fortran {
+namespace parser {
+
+class ParsingLog {
+public:
+  void Note(const char *at, const MessageFixedText &tag, bool pass);
+  void Dump(std::ostream &) const;
+
+private:
+  struct LogForPosition {
+    struct Entries {
+      int passes{0};
+      int failures{0};
+    };
+    std::map<MessageFixedText, Entries> perTag;
+  };
+  std::map<std::size_t, LogForPosition> perPos_;
+};
+
+template<typename PA> class InstrumentedParser {
+public:
+  using resultType = typename PA::resultType;
+  constexpr InstrumentedParser(const InstrumentedParser &) = default;
+  constexpr InstrumentedParser(const MessageFixedText &tag, const PA &parser)
+    : tag_{tag}, parser_{parser} {}
+  std::optional<resultType> Parse(ParseState *state) const {
+    const char *at{state->GetLocation()};
+    std::optional<resultType> result{parser_.Parse(state)};
+    if (UserState * ustate{state->userState()}) {
+      if (ParsingLog * log{ustate->log()}) {
+        log->Note(at, tag_, result.has_value());
+      }
+    }
+    return result;
+  }
+
+private:
+  const MessageFixedText tag_;
+  const PA parser_;
+};
+
+template<typename PA>
+inline constexpr auto instrumented(
+    const MessageFixedText &tag, const PA &parser) {
+  return InstrumentedParser{tag, parser};
+}
+}  // namespace parser
+}  // namespace Fortran
+#endif  // FORTRAN_PARSER_INSTRUMENTED_PARSER_H_