[flang] flang-omp-report replace std::map with llvm::DenseMap

[josh.mottley.arm]

Summary

This patch replaces the uses of std::map with llvm::DenseMap in the
flang-omp-report plugin. It also removed the 'constructClauseCount' map
due to no longer being needed after the plugin was stripped down.
This is a one of several patches focusing on switching containers from STL to LLVM's ADT library.

[kiranchandramohan]

LGTM.

flang/examples/flang-omp-report-plugin/flang-omp-report-visitor.h

 //===-- examples/flang-omp-report-plugin/flang-omp-report-visitor.h -------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef FORTRAN_FLANG_OMP_REPORT_VISITOR_H
 #define FORTRAN_FLANG_OMP_REPORT_VISITOR_H
 
 #include "flang/Parser/parse-tree-visitor.h"
 #include "flang/Parser/parse-tree.h"
 #include "flang/Parser/parsing.h"
 
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 
 #include <deque>
-#include <map>
 #include <string>
 
 namespace Fortran {
 namespace parser {
 struct ClauseInfo {
   std::string clause;
   std::string clauseDetails;
   ClauseInfo() {}
struct OpenMPCounterVisitor {
   void Post(const OmpScheduleClause::ScheduleType &c);
   void Post(const OmpIfClause::DirectiveNameModifier &c);
   void Post(const OmpCancelType::Type &c);
   void Post(const OmpClause &c);
   void PostClauseCommon(const ClauseInfo &ci);
   void Post(const DoConstruct &);
 
   std::string clauseDetails{""};
-  std::map<std::pair<std::string, std::string>, int> constructClauseCount;
 
   // curLoopLogRecord and loopLogRecordStack store
   // pointers to this datastructure's entries. Hence a
   // vector cannot be used since pointers are invalidated
   // on resize. Next best option seems to be deque. Also a
   // list cannot be used since YAML gen requires a
   // datastructure which can be accessed through indices.
   std::deque<LogRecord> constructClauses;
 
   LogRecord *curLoopLogRecord{nullptr};
   llvm::SmallVector<LogRecord *> loopLogRecordStack;
   llvm::SmallVector<OmpWrapperType *> ompWrapperStack;
-  std::map<OmpWrapperType *, llvm::SmallVector<ClauseInfo>> clauseStrings;
+  llvm::DenseMap<OmpWrapperType *, llvm::SmallVector<ClauseInfo>> clauseStrings;
   Parsing *parsing{nullptr};
 };
 } // namespace parser
 } // namespace Fortran
 
 #endif /* FORTRAN_FLANG_OMP_REPORT_VISITOR_H */

flang/examples/flang-omp-report-plugin/flang-omp-report-visitor.cpp

void OpenMPCounterVisitor::PostClauseCommon(const ClauseInfo &ci) {
   // the OpenMP construct for the loop construct. So the end loop is left
   // hanging as a separate executable construct. If a nowait clause is seen in
   // an end loop construct we have to find the associated loop construct and
   // add nowait to its list of clauses. Note: This is not a bug in flang, the
   // parse tree is corrected during semantic analysis.
   if (ci.clause == "nowait") {
     assert(curLoopLogRecord &&
         "loop Construct should be visited before a nowait clause");
-    constructClauseCount[std::make_pair(
-        curLoopLogRecord->construct, ci.clause)]++;
     curLoopLogRecord->clauses.push_back(ci);
   } else {
     assert(!ompWrapperStack.empty() &&
         "Construct should be visited before clause");
-    constructClauseCount[std::make_pair(
-        getName(*ompWrapperStack.back()), ci.clause)]++;
     clauseStrings[ompWrapperStack.back()].push_back(ci);
   }
 }
 void OpenMPCounterVisitor::Post(const DoConstruct &) {
   curLoopLogRecord = loopLogRecordStack.back();
   loopLogRecordStack.pop_back();
 }
 } // namespace parser
 } // namespace Fortran