Package org.antlr.runtime.debug

Class Profiler

  • All Implemented Interfaces:
    DebugEventListener
    public class Profiler
extends BlankDebugEventListener
    Using the debug event interface, track what is happening in the parser and record statistics about the runtime.

    • Constructor Detail

      • Profiler

        public Profiler()

    • Method Detail

      • enterRule

        public void enterRule​(String grammarFileName,
                      String ruleName)
        Description copied from interface: DebugEventListener
        The parser has just entered a rule. No decision has been made about which alt is predicted. This is fired AFTER init actions have been executed. Attributes are defined and available etc... The grammarFileName allows composite grammars to jump around among multiple grammar files.
        Specified by:
        enterRule in interface DebugEventListener
        Overrides:
        enterRule in class BlankDebugEventListener

      • exitRule

        public void exitRule​(String grammarFileName,
                     String ruleName)
        Description copied from interface: DebugEventListener
        This is the last thing executed before leaving a rule. It is executed even if an exception is thrown. This is triggered after error reporting and recovery have occurred (unless the exception is not caught in this rule). This implies an "exitAlt" event. The grammarFileName allows composite grammars to jump around among multiple grammar files.
        Specified by:
        exitRule in interface DebugEventListener
        Overrides:
        exitRule in class BlankDebugEventListener

      • examineRuleMemoization

        public void examineRuleMemoization​(IntStream input,
                                   int ruleIndex,
                                   int stopIndex,
                                   String ruleName)
        Track memoization; this is not part of standard debug interface but is triggered by profiling. Code gen inserts an override for this method in the recognizer, which triggers this method. Called from alreadyParsedRule().

      • memoize

        public void memoize​(IntStream input,
                    int ruleIndex,
                    int ruleStartIndex,
                    String ruleName)
        Warning: doesn't track success/failure, just unique recording event

      • location

        public void location​(int line,
                     int pos)
        Description copied from interface: DebugEventListener
        To watch a parser move through the grammar, the parser needs to inform the debugger what line/charPos it is passing in the grammar. For now, this does not know how to switch from one grammar to the other and back for island grammars etc... This should also allow breakpoints because the debugger can stop the parser whenever it hits this line/pos.
        Specified by:
        location in interface DebugEventListener
        Overrides:
        location in class BlankDebugEventListener

      • enterDecision

        public void enterDecision​(int decisionNumber,
                          boolean couldBacktrack)
        Description copied from interface: DebugEventListener
        Every decision, fixed k or arbitrary, has an enter/exit event so that a GUI can easily track what LT/consume events are associated with prediction. You will see a single enter/exit subrule but multiple enter/exit decision events, one for each loop iteration.
        Specified by:
        enterDecision in interface DebugEventListener
        Overrides:
        enterDecision in class BlankDebugEventListener

      • inDecision

        public boolean inDecision()
        The parser is in a decision if the decision depth > 0. This works for backtracking also, which can have nested decisions.

      • beginBacktrack

        public void beginBacktrack​(int level)
        Track backtracking decisions. You'll see a fixed or cyclic decision and then a backtrack. enter rule ... enter decision LA and possibly consumes (for cyclic DFAs) begin backtrack level mark m rewind m end backtrack level, success exit decision ... exit rule
        Specified by:
        beginBacktrack in interface DebugEventListener
        Overrides:
        beginBacktrack in class BlankDebugEventListener

      • rewind

        public void rewind​(int i)
        Description copied from interface: DebugEventListener
        After an arbitrairly long lookahead as with a cyclic DFA (or with any backtrack), this informs the debugger that stream should be rewound to the position associated with marker.
        Specified by:
        rewind in interface DebugEventListener
        Overrides:
        rewind in class BlankDebugEventListener

      • rewind

        public void rewind()
        Description copied from interface: DebugEventListener
        Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still.
        Specified by:
        rewind in interface DebugEventListener
        Overrides:
        rewind in class BlankDebugEventListener

      • recognitionException

        public void recognitionException​(RecognitionException e)
        Description copied from interface: DebugEventListener
        A recognition exception occurred such as NoViableAltException. I made this a generic event so that I can alter the exception hierachy later without having to alter all the debug objects. Upon error, the stack of enter rule/subrule must be properly unwound. If no viable alt occurs it is within an enter/exit decision, which also must be rewound. Even the rewind for each mark must be unwount. In the Java target this is pretty easy using try/finally, if a bit ugly in the generated code. The rewind is generated in DFA.predict() actually so no code needs to be generated for that. For languages w/o this "finally" feature (C++?), the target implementor will have to build an event stack or something. Across a socket for remote debugging, only the RecognitionException data fields are transmitted. The token object or whatever that caused the problem was the last object referenced by LT. The immediately preceding LT event should hold the unexpected Token or char. Here is a sample event trace for grammar: b : C ({;}A|B) // {;} is there to prevent A|B becoming a set | D ; The sequence for this rule (with no viable alt in the subrule) for input 'c c' (there are 3 tokens) is: commence LT(1) enterRule b location 7 1 enter decision 3 LT(1) exit decision 3 enterAlt1 location 7 5 LT(1) consumeToken [c/<4>,1:0] location 7 7 enterSubRule 2 enter decision 2 LT(1) LT(1) recognitionException NoViableAltException 2 1 2 exit decision 2 exitSubRule 2 beginResync LT(1) consumeToken [c/<4>,1:1] LT(1) endResync LT(-1) exitRule b terminate
        Specified by:
        recognitionException in interface DebugEventListener
        Overrides:
        recognitionException in class BlankDebugEventListener

      • terminate

        public void terminate()
        Description copied from interface: DebugEventListener
        Parsing is over; successfully or not. Mostly useful for telling remote debugging listeners that it's time to quit. When the rule invocation level goes to zero at the end of a rule, we are done parsing.
        Specified by:
        terminate in interface DebugEventListener
        Overrides:
        terminate in class BlankDebugEventListener

      • setParser

        public void setParser​(DebugParser parser)

      • toNotifyString

        public String toNotifyString()

      • getDecisionStatsDump

        public String getDecisionStatsDump()

      • trim

        protected int[] trim​(int[] X,
                     int n)

      • toArray

        protected int[] toArray​(List<Integer> a)

      • getNumberOfHiddenTokens

        public int getNumberOfHiddenTokens​(int i,
                                   int j)
        Get num hidden tokens between i..j inclusive

      • locationDescription

        protected String locationDescription()

      • locationDescription

        protected String locationDescription​(String file,
                                     String rule,
                                     int line,
                                     int pos)