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runtime-linux/antlr4-runtime/atn/ProfilingATNSimulator.cpp

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+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#include "atn/PredicateEvalInfo.h"
+#include "atn/LookaheadEventInfo.h"
+#include "Parser.h"
+#include "atn/ATNConfigSet.h"
+#include "support/CPPUtils.h"
+
+#include "atn/ProfilingATNSimulator.h"
+
+using namespace antlr4;
+using namespace antlr4::atn;
+using namespace antlr4::dfa;
+using namespace antlrcpp;
+
+using namespace std::chrono;
+
+ProfilingATNSimulator::ProfilingATNSimulator(Parser *parser)
+  : ParserATNSimulator(parser, parser->getInterpreter<ParserATNSimulator>()->atn,
+                       parser->getInterpreter<ParserATNSimulator>()->decisionToDFA,
+                       parser->getInterpreter<ParserATNSimulator>()->getSharedContextCache()) {
+  for (size_t i = 0; i < atn.decisionToState.size(); i++) {
+    _decisions.push_back(DecisionInfo(i));
+  }
+}
+
+size_t ProfilingATNSimulator::adaptivePredict(TokenStream *input, size_t decision, ParserRuleContext *outerContext) {
+  auto onExit = finally([this](){
+    _currentDecision = 0; // Originally -1, but that makes no sense (index into a vector and init value is also 0).
+  });
+
+  _sllStopIndex = -1;
+  _llStopIndex = -1;
+  _currentDecision = decision;
+  high_resolution_clock::time_point start = high_resolution_clock::now(); // expensive but useful info
+  size_t alt = ParserATNSimulator::adaptivePredict(input, decision, outerContext);
+  high_resolution_clock::time_point stop = high_resolution_clock::now();
+  _decisions[decision].timeInPrediction += duration_cast<nanoseconds>(stop - start).count();
+  _decisions[decision].invocations++;
+
+  long long SLL_k = _sllStopIndex - _startIndex + 1;
+  _decisions[decision].SLL_TotalLook += SLL_k;
+  _decisions[decision].SLL_MinLook = _decisions[decision].SLL_MinLook == 0 ? SLL_k : std::min(_decisions[decision].SLL_MinLook, SLL_k);
+  if (SLL_k > _decisions[decision].SLL_MaxLook) {
+    _decisions[decision].SLL_MaxLook = SLL_k;
+    _decisions[decision].SLL_MaxLookEvent = std::make_shared<LookaheadEventInfo>(decision, nullptr, alt, input, _startIndex, _sllStopIndex, false);
+  }
+
+  if (_llStopIndex >= 0) {
+    long long LL_k = _llStopIndex - _startIndex + 1;
+    _decisions[decision].LL_TotalLook += LL_k;
+    _decisions[decision].LL_MinLook = _decisions[decision].LL_MinLook == 0 ? LL_k : std::min(_decisions[decision].LL_MinLook, LL_k);
+    if (LL_k > _decisions[decision].LL_MaxLook) {
+      _decisions[decision].LL_MaxLook = LL_k;
+      _decisions[decision].LL_MaxLookEvent = std::make_shared<LookaheadEventInfo>(decision, nullptr, alt, input, _startIndex, _llStopIndex, true);
+    }
+  }
+
+  return alt;
+}
+
+DFAState* ProfilingATNSimulator::getExistingTargetState(DFAState *previousD, size_t t) {
+  // this method is called after each time the input position advances
+  // during SLL prediction
+  _sllStopIndex = (int)_input->index();
+
+  DFAState *existingTargetState = ParserATNSimulator::getExistingTargetState(previousD, t);
+  if (existingTargetState != nullptr) {
+    _decisions[_currentDecision].SLL_DFATransitions++; // count only if we transition over a DFA state
+    if (existingTargetState == ERROR.get()) {
+      _decisions[_currentDecision].errors.push_back(
+        ErrorInfo(_currentDecision, previousD->configs.get(), _input, _startIndex, _sllStopIndex, false)
+      );
+    }
+  }
+
+  _currentState = existingTargetState;
+  return existingTargetState;
+}
+
+DFAState* ProfilingATNSimulator::computeTargetState(DFA &dfa, DFAState *previousD, size_t t) {
+  DFAState *state = ParserATNSimulator::computeTargetState(dfa, previousD, t);
+  _currentState = state;
+  return state;
+}
+
+std::unique_ptr<ATNConfigSet> ProfilingATNSimulator::computeReachSet(ATNConfigSet *closure, size_t t, bool fullCtx) {
+  if (fullCtx) {
+    // this method is called after each time the input position advances
+    // during full context prediction
+    _llStopIndex = (int)_input->index();
+  }
+
+  std::unique_ptr<ATNConfigSet> reachConfigs = ParserATNSimulator::computeReachSet(closure, t, fullCtx);
+  if (fullCtx) {
+    _decisions[_currentDecision].LL_ATNTransitions++; // count computation even if error
+    if (reachConfigs != nullptr) {
+    } else { // no reach on current lookahead symbol. ERROR.
+      // TO_DO: does not handle delayed errors per getSynValidOrSemInvalidAltThatFinishedDecisionEntryRule()
+      _decisions[_currentDecision].errors.push_back(ErrorInfo(_currentDecision, closure, _input, _startIndex, _llStopIndex, true));
+    }
+  } else {
+    ++_decisions[_currentDecision].SLL_ATNTransitions;
+    if (reachConfigs != nullptr) {
+    } else { // no reach on current lookahead symbol. ERROR.
+      _decisions[_currentDecision].errors.push_back(ErrorInfo(_currentDecision, closure, _input, _startIndex, _sllStopIndex, false));
+    }
+  }
+  return reachConfigs;
+}
+
+bool ProfilingATNSimulator::evalSemanticContext(Ref<SemanticContext> const& pred, ParserRuleContext *parserCallStack,
+                                                size_t alt, bool fullCtx) {
+  bool result = ParserATNSimulator::evalSemanticContext(pred, parserCallStack, alt, fullCtx);
+  if (!(std::dynamic_pointer_cast<SemanticContext::PrecedencePredicate>(pred) != nullptr)) {
+    bool fullContext = _llStopIndex >= 0;
+    int stopIndex = fullContext ? _llStopIndex : _sllStopIndex;
+    _decisions[_currentDecision].predicateEvals.push_back(
+      PredicateEvalInfo(_currentDecision, _input, _startIndex, stopIndex, pred, result, alt, fullCtx));
+  }
+
+  return result;
+}
+
+void ProfilingATNSimulator::reportAttemptingFullContext(DFA &dfa, const BitSet &conflictingAlts, ATNConfigSet *configs,
+                                                        size_t startIndex, size_t stopIndex) {
+  if (conflictingAlts.count() > 0) {
+    conflictingAltResolvedBySLL = conflictingAlts.nextSetBit(0);
+  } else {
+    conflictingAltResolvedBySLL = configs->getAlts().nextSetBit(0);
+  }
+  _decisions[_currentDecision].LL_Fallback++;
+  ParserATNSimulator::reportAttemptingFullContext(dfa, conflictingAlts, configs, startIndex, stopIndex);
+}
+
+void ProfilingATNSimulator::reportContextSensitivity(DFA &dfa, size_t prediction, ATNConfigSet *configs,
+                                                     size_t startIndex, size_t stopIndex) {
+  if (prediction != conflictingAltResolvedBySLL) {
+    _decisions[_currentDecision].contextSensitivities.push_back(
+      ContextSensitivityInfo(_currentDecision, configs, _input, startIndex, stopIndex)
+    );
+  }
+  ParserATNSimulator::reportContextSensitivity(dfa, prediction, configs, startIndex, stopIndex);
+}
+
+void ProfilingATNSimulator::reportAmbiguity(DFA &dfa, DFAState *D, size_t startIndex, size_t stopIndex, bool exact,
+                                            const BitSet &ambigAlts, ATNConfigSet *configs) {
+  size_t prediction;
+  if (ambigAlts.count() > 0) {
+    prediction = ambigAlts.nextSetBit(0);
+  } else {
+    prediction = configs->getAlts().nextSetBit(0);
+  }
+  if (configs->fullCtx && prediction != conflictingAltResolvedBySLL) {
+    // Even though this is an ambiguity we are reporting, we can
+    // still detect some context sensitivities.  Both SLL and LL
+    // are showing a conflict, hence an ambiguity, but if they resolve
+    // to different minimum alternatives we have also identified a
+    // context sensitivity.
+    _decisions[_currentDecision].contextSensitivities.push_back(
+      ContextSensitivityInfo(_currentDecision, configs, _input, startIndex, stopIndex)
+    );
+  }
+  _decisions[_currentDecision].ambiguities.push_back(
+    AmbiguityInfo(_currentDecision, configs, ambigAlts, _input, startIndex, stopIndex, configs->fullCtx)
+  );
+  ParserATNSimulator::reportAmbiguity(dfa, D, startIndex, stopIndex, exact, ambigAlts, configs);
+}
+
+std::vector<DecisionInfo> ProfilingATNSimulator::getDecisionInfo() const {
+  return _decisions;
+}
+
+DFAState* ProfilingATNSimulator::getCurrentState() const {
+  return _currentState;
+}