#include "CodeGenTarget.h"
#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include <list>
// Another way of thinking about this transition is we are mapping a NDFA with
// two states [0x01] and [0x10] into a DFA with a single state [0x01, 0x10].
//
+// A State instance also contains a collection of transitions from that state:
+// a map from inputs to new states.
//
namespace {
class State {
public:
static int currentStateNum;
- int stateNum;
- bool isInitial;
- std::set<unsigned> stateInfo;
+ // stateNum is the only member used for equality/ordering, all other members
+ // can be mutated even in const State objects.
+ const int stateNum;
+ mutable bool isInitial;
+ mutable std::set<unsigned> stateInfo;
+ typedef std::map<unsigned, const State *> TransitionMap;
+ mutable TransitionMap Transitions;
State();
- State(const State &S);
+
+ bool operator<(const State &s) const {
+ return stateNum < s.stateNum;
+ }
//
// canAddInsnClass - Returns true if an instruction of type InsnClass is a
// AddInsnClass - Return all combinations of resource reservation
// which are possible from this state (PossibleStates).
//
- void AddInsnClass(unsigned InsnClass, std::set<unsigned> &PossibleStates);
-};
-} // End anonymous namespace.
-
-
-namespace {
-struct Transition {
- public:
- static int currentTransitionNum;
- int transitionNum;
- State *from;
- unsigned input;
- State *to;
-
- Transition(State *from_, unsigned input_, State *to_);
-};
-} // End anonymous namespace.
-
-
-//
-// Comparators to keep set of states sorted.
-//
-namespace {
-struct ltState {
- bool operator()(const State *s1, const State *s2) const;
-};
-
-struct ltTransition {
- bool operator()(const Transition *s1, const Transition *s2) const;
+ void AddInsnClass(unsigned InsnClass, std::set<unsigned> &PossibleStates) const;
+ //
+ // addTransition - Add a transition from this state given the input InsnClass
+ //
+ void addTransition(unsigned InsnClass, const State *To) const;
+ //
+ // hasTransition - Returns true if there is a transition from this state
+ // given the input InsnClass
+ //
+ bool hasTransition(unsigned InsnClass) const;
};
} // End anonymous namespace.
-
//
// class DFA: deterministic finite automaton for processor resource tracking.
//
DFA();
// Set of states. Need to keep this sorted to emit the transition table.
- std::set<State*, ltState> states;
+ typedef std::set<State> StateSet;
+ StateSet states;
- // Map from a state to the list of transitions with that state as source.
- std::map<State*, std::set<Transition*, ltTransition>, ltState>
- stateTransitions;
State *currentState;
- // Highest valued Input seen.
- unsigned LargestInput;
-
//
// Modify the DFA.
//
- void initialize();
- void addState(State *);
- void addTransition(Transition *);
-
- //
- // getTransition - Return the state when a transition is made from
- // State From with Input I. If a transition is not found, return NULL.
- //
- State *getTransition(State *, unsigned);
-
- //
- // isValidTransition: Predicate that checks if there is a valid transition
- // from state From on input InsnClass.
- //
- bool isValidTransition(State *From, unsigned InsnClass);
+ const State &newState();
//
// writeTable: Print out a table representing the DFA.
//
-// Constructors for State, Transition, and DFA
+// Constructors and destructors for State and DFA
//
State::State() :
stateNum(currentStateNum++), isInitial(false) {}
+DFA::DFA(): currentState(nullptr) {}
-State::State(const State &S) :
- stateNum(currentStateNum++), isInitial(S.isInitial),
- stateInfo(S.stateInfo) {}
-
-
-Transition::Transition(State *from_, unsigned input_, State *to_) :
- transitionNum(currentTransitionNum++), from(from_), input(input_),
- to(to_) {}
-
-
-DFA::DFA() :
- LargestInput(0) {}
-
-
-bool ltState::operator()(const State *s1, const State *s2) const {
- return (s1->stateNum < s2->stateNum);
+//
+// addTransition - Add a transition from this state given the input InsnClass
+//
+void State::addTransition(unsigned InsnClass, const State *To) const {
+ assert(!Transitions.count(InsnClass) &&
+ "Cannot have multiple transitions for the same input");
+ Transitions[InsnClass] = To;
}
-bool ltTransition::operator()(const Transition *s1, const Transition *s2) const {
- return (s1->input < s2->input);
+//
+// hasTransition - Returns true if there is a transition from this state
+// given the input InsnClass
+//
+bool State::hasTransition(unsigned InsnClass) const {
+ return Transitions.count(InsnClass) > 0;
}
//
// which are possible from this state (PossibleStates).
//
void State::AddInsnClass(unsigned InsnClass,
- std::set<unsigned> &PossibleStates) {
+ std::set<unsigned> &PossibleStates) const {
//
// Iterate over all resource states in currentState.
//
// be added to the packet represented by this state.
//
bool State::canAddInsnClass(unsigned InsnClass) const {
- for (std::set<unsigned>::iterator SI = stateInfo.begin();
+ for (std::set<unsigned>::const_iterator SI = stateInfo.begin();
SI != stateInfo.end(); ++SI) {
if (~*SI & InsnClass)
return true;
}
-void DFA::initialize() {
- currentState->isInitial = true;
-}
-
-
-void DFA::addState(State *S) {
- assert(!states.count(S) && "State already exists");
- states.insert(S);
-}
-
-
-void DFA::addTransition(Transition *T) {
- // Update LargestInput.
- if (T->input > LargestInput)
- LargestInput = T->input;
-
- // Add the new transition.
- bool Added = stateTransitions[T->from].insert(T).second;
- assert(Added && "Cannot have multiple states for the same input");
- (void)Added;
-}
-
-
-//
-// getTransition - Return the state when a transition is made from
-// State From with Input I. If a transition is not found, return NULL.
-//
-State *DFA::getTransition(State *From, unsigned I) {
- // Do we have a transition from state From?
- if (!stateTransitions.count(From))
- return NULL;
-
- // Do we have a transition from state From with Input I?
- Transition TVal(NULL, I, NULL);
- // Do not count this temporal instance
- Transition::currentTransitionNum--;
- std::set<Transition*, ltTransition>::iterator T =
- stateTransitions[From].find(&TVal);
- if (T != stateTransitions[From].end())
- return (*T)->to;
-
- return NULL;
-}
-
-
-bool DFA::isValidTransition(State *From, unsigned InsnClass) {
- return (getTransition(From, InsnClass) != NULL);
+const State &DFA::newState() {
+ auto IterPair = states.insert(State());
+ assert(IterPair.second && "State already exists");
+ return *IterPair.first;
}
int State::currentStateNum = 0;
-int Transition::currentTransitionNum = 0;
DFAPacketizerEmitter::DFAPacketizerEmitter(RecordKeeper &R):
TargetName(CodeGenTarget(R).getName()),
//
//
void DFA::writeTableAndAPI(raw_ostream &OS, const std::string &TargetName) {
- std::set<State*, ltState>::iterator SI = states.begin();
+ static const std::string SentinelEntry = "{-1, -1}";
+ DFA::StateSet::iterator SI = states.begin();
// This table provides a map to the beginning of the transitions for State s
// in DFAStateInputTable.
std::vector<int> StateEntry(states.size());
// to construct the StateEntry table.
int ValidTransitions = 0;
for (unsigned i = 0; i < states.size(); ++i, ++SI) {
+ assert ((SI->stateNum == (int) i) && "Mismatch in state numbers");
StateEntry[i] = ValidTransitions;
- for (unsigned j = 0; j <= LargestInput; ++j) {
- assert (((*SI)->stateNum == (int) i) && "Mismatch in state numbers");
- State *To = getTransition(*SI, j);
- if (To == NULL)
- continue;
-
- OS << "{" << j << ", "
- << To->stateNum
+ for (State::TransitionMap::iterator
+ II = SI->Transitions.begin(), IE = SI->Transitions.end();
+ II != IE; ++II) {
+ OS << "{" << II->first << ", "
+ << II->second->stateNum
<< "}, ";
- ++ValidTransitions;
}
+ ValidTransitions += SI->Transitions.size();
// If there are no valid transitions from this stage, we need a sentinel
// transition.
if (ValidTransitions == StateEntry[i]) {
- OS << "{-1, -1},";
+ OS << SentinelEntry << ",";
++ValidTransitions;
}
OS << "\n";
}
+
+ // Print out a sentinel entry at the end of the StateInputTable. This is
+ // needed to iterate over StateInputTable in DFAPacketizer::ReadTable()
+ OS << SentinelEntry << "\n";
+
OS << "};\n\n";
OS << "const unsigned int " << TargetName << "DFAStateEntryTable[] = {\n";
for (unsigned i = 0; i < states.size(); ++i)
OS << StateEntry[i] << ", ";
+ // Print out the index to the sentinel entry in StateInputTable
+ OS << ValidTransitions << ", ";
+
OS << "\n};\n";
OS << "} // namespace\n";
// Run a worklist algorithm to generate the DFA.
//
DFA D;
- State *Initial = new State;
+ const State *Initial = &D.newState();
Initial->isInitial = true;
Initial->stateInfo.insert(0x0);
- D.addState(Initial);
- SmallVector<State*, 32> WorkList;
- std::map<std::set<unsigned>, State*> Visited;
+ SmallVector<const State*, 32> WorkList;
+ std::map<std::set<unsigned>, const State*> Visited;
WorkList.push_back(Initial);
// Add S' to Visited
//
while (!WorkList.empty()) {
- State *current = WorkList.pop_back_val();
+ const State *current = WorkList.pop_back_val();
for (DenseSet<unsigned>::iterator CI = allInsnClasses.begin(),
CE = allInsnClasses.end(); CI != CE; ++CI) {
unsigned InsnClass = *CI;
// If we haven't already created a transition for this input
// and the state can accommodate this InsnClass, create a transition.
//
- if (!D.getTransition(current, InsnClass) &&
+ if (!current->hasTransition(InsnClass) &&
current->canAddInsnClass(InsnClass)) {
- State *NewState = NULL;
+ const State *NewState;
current->AddInsnClass(InsnClass, NewStateResources);
- assert(NewStateResources.size() && "New states must be generated");
+ assert(!NewStateResources.empty() && "New states must be generated");
//
// If we have seen this state before, then do not create a new state.
//
//
- std::map<std::set<unsigned>, State*>::iterator VI;
- if ((VI = Visited.find(NewStateResources)) != Visited.end())
+ auto VI = Visited.find(NewStateResources);
+ if (VI != Visited.end())
NewState = VI->second;
else {
- NewState = new State;
+ NewState = &D.newState();
NewState->stateInfo = NewStateResources;
- D.addState(NewState);
Visited[NewStateResources] = NewState;
WorkList.push_back(NewState);
}
-
- Transition *NewTransition = new Transition(current, InsnClass,
- NewState);
- D.addTransition(NewTransition);
+
+ current->addTransition(InsnClass, NewState);
}
}
}
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