michael@0: 
michael@0: /**
michael@0:  * A test case spec is an array of objects of the following kind:
michael@0:  *  { 'match': Num|Str|Null,
michael@0:  *    'body': Num|Str|Null,
michael@0:  *    'fallthrough': Boolean }
michael@0:  *
michael@0:  * If the 'match' is null, then it represents a 'default:'
michael@0:  * If the 'match' is not null, it represents a 'case X:' where X is the value.
michael@0:  * If the 'body' is null, then it means that the case body is empty.  Otherwise,
michael@0:  * it means that the case body is a single 'arr.push(V);' where "arr" is an input
michael@0:  * array to the function containing the switch statement, and V is the value.
michael@0:  * If 'fallthrough' is false, then the body is terminated with a break, otherwise
michael@0:  * it is not.
michael@0:  *
michael@0:  * So a spec: [{'match':3, 'body':null, 'fallthrough':false}, {'match':null, 'body':"foo", 'fallthrough':true}]
michael@0:  * Represents a switch function:
michael@0:  *  function(x, arr) {
michael@0:  *      switch(x) {
michael@0:  *      case 3:
michael@0:  *          break;
michael@0:  *      default:
michael@0:  *          arr.push('foo');
michael@0:  *      }
michael@0:  *  }
michael@0:  *
michael@0:  * GenerateSpecPermutes generates a bunch of relevant specs, using the given case match-values,
michael@0:  * and appends them to result the array passed into it.
michael@0:  *
michael@0:  * InterpretSwitch takes a spec, a value, and a result array, and behaves as if the switch specified
michael@0:  * by the spec had been called on the value and the result array.
michael@0:  *
michael@0:  * VerifySwitchSpec is there but not used in the code.  I was using it while testing the test case
michael@0:  * generator.  It verifies that a switch spec is sane.
michael@0:  *
michael@0:  * RunSpec uses eval to run the test directly.  It's not used currently.
michael@0:  *
michael@0:  * GenerateSwitchCode generates a string of the form "function NAME(x, arg) { .... }" which
michael@0:  * contains the switch modeled by its input spec.
michael@0:  *
michael@0:  * RunTest is there to be used from within the generated script.  Its code is dumped out
michael@0:  * to the generated script text, and invoked there.
michael@0:  *
michael@0:  * Hope all of this makes some sort of sense.
michael@0:  *  -kannan
michael@0:  */
michael@0: 
michael@0: /** HELPERS **/
michael@0: 
michael@0: function ASSERT(cond, msg) { assertEq(cond, true, msg); }
michael@0: 
michael@0: function IsUndef(x) { return typeof(x) == 'undefined'; }
michael@0: function IsNull(x) { return typeof(x) == 'object' && x == null; }
michael@0: function IsNum(x) { return typeof(x) == 'number'; }
michael@0: function IsStr(x) { return typeof(x) == 'string'; }
michael@0: function IsBool(x) { return typeof(x) == 'boolean'; }
michael@0: 
michael@0: function Repr(x) {
michael@0:     ASSERT(IsNum(x) || IsStr(x), "Repr");
michael@0:     if(IsNum(x)) { return ""+x; }
michael@0:     else { return "'"+x+"'"; }
michael@0: }
michael@0: 
michael@0: function RandBool() { return Math.random() >= 0.5; }
michael@0: function RandInt(max) {
michael@0:     if(IsUndef(max)) { max = 0x7fffffff; }
michael@0:     return (Math.random() * max)|0;
michael@0: }
michael@0: 
michael@0: var CHARS = "abcdefghijklmnopqrstuvywxyzABCDEFGHIJKLMNOPQRSTUVYWXYZ0123456789~!@#$%^&*()-_=+{}[]";
michael@0: function RandStr() {
michael@0:     var arr = [];
michael@0:     var len = Math.floor(Math.random() * 10) + 1;
michael@0:     for(var i = 0; i < len; i++) {
michael@0:         var c = Math.floor(Math.random() * CHARS.length);
michael@0:         arr.push(CHARS[c]);
michael@0:     }
michael@0:     return arr.join('');
michael@0: }
michael@0: 
michael@0: function RandVal() { return RandBool() ? RandInt() : RandStr(); }
michael@0: 
michael@0: /**
michael@0:  * Compare two arrays and ensure they are equal.
michael@0:  */
michael@0: function ArraysEqual(arr1, arr2) {
michael@0:     ASSERT(arr1.length == arr2.length, "Lengths not equal");
michael@0:     for(var i = 0; i < arr1.length; i++) {
michael@0:         ASSERT(typeof(arr1[i]) == typeof(arr2[i]), "Types not equal for position " + i);
michael@0:         ASSERT(arr1[i] == arr2[i], "Values not equal for position " + i);
michael@0:     }
michael@0: }
michael@0: 
michael@0: function VerifySwitchSpec(spec) {
michael@0:     var foundDefault = undefined;
michael@0:     for(var i = 0; i < spec.length; i++) {
michael@0:         var caseSpec = spec[i],
michael@0:             match = caseSpec.match,
michael@0:             body = caseSpec.body,
michael@0:             fallthrough = caseSpec.fallthrough;
michael@0:         ASSERT(IsNum(match) || IsStr(match) || IsNull(match), "Invalid case match for " + i);
michael@0:         ASSERT(IsNum(body) || IsStr(body) || IsNull(body), "Invalid case body for " + i);
michael@0:         ASSERT(IsBool(fallthrough), "Invalid fallthrough for " + i);
michael@0: 
michael@0:         if(IsNull(match)) {
michael@0:             ASSERT(IsUndef(foundDefault), "Duplicate default found at " + i);
michael@0:             foundDefault = i;
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Do a manual interpretation of a particular spec, given an input
michael@0:  * and outputting to an output array.
michael@0:  */
michael@0: function InterpretSwitch(spec, input, outputArray) {
michael@0:     var foundMatch = undefined, foundDefault = undefined;
michael@0:     // Go through cases, trying to find a matching clause.
michael@0:     for(var i = 0; i < spec.length; i++) {
michael@0:         var caseSpec = spec[i], match = caseSpec.match;
michael@0: 
michael@0:         if(IsNull(match)) {
michael@0:             foundDefault = i;
michael@0:             continue;
michael@0:         } else if(match === input) {
michael@0:             foundMatch = i;
michael@0:             break;
michael@0:         }
michael@0:     }
michael@0:     // Select either matching clause or default.
michael@0:     var matchI = IsNum(foundMatch) ? foundMatch : foundDefault;
michael@0: 
michael@0:     // If match or default was found, interpret body from that point on.
michael@0:     if(IsNum(matchI)) {
michael@0:         for(var i = matchI; i < spec.length; i++) {
michael@0:             var caseSpec = spec[i],
michael@0:                 match = caseSpec.match,
michael@0:                 body = caseSpec.body,
michael@0:                 fallthrough = caseSpec.fallthrough;
michael@0:             if(!IsNull(body)) { outputArray.push(body); }
michael@0:             if(!fallthrough) { break; }
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Generate the code string for a javascript function containing the
michael@0:  * switch specified by the spec, in pure JS syntax.
michael@0:  */
michael@0: function GenerateSwitchCode(spec, name) {
michael@0:     var lines = [];
michael@0:     if(!name) { name = ""; }
michael@0: 
michael@0:     lines.push("function "+name+"(x, arr) {");
michael@0:     lines.push("    switch(x) {");
michael@0:     for(var i = 0; i < spec.length; i++) {
michael@0:         var caseSpec = spec[i],
michael@0:             match = caseSpec.match,
michael@0:             body = caseSpec.body,
michael@0:             fallthrough = caseSpec.fallthrough;
michael@0: 
michael@0:         if(IsNull(match))   { lines.push("    default:"); }
michael@0:         else                { lines.push("    case "+Repr(match)+":"); }
michael@0: 
michael@0:         if(!IsNull(body))   { lines.push("        arr.push("+Repr(body)+");"); }
michael@0:         if(!fallthrough)    { lines.push("        break;"); }
michael@0:     }
michael@0:     lines.push("    }");
michael@0:     lines.push("}");
michael@0:     return lines.join("\n");
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Generates all possible specs for a given set of case match values.
michael@0:  */
michael@0: function GenerateSpecPermutes(matchVals, resultArray) {
michael@0:     ASSERT((0 < matchVals.length) && (matchVals.length <= 5), "Invalid matchVals");
michael@0:     var maxPermuteBody = (1 << matchVals.length) - 1;
michael@0:     for(var bod_pm = 0; bod_pm <= maxPermuteBody; bod_pm++) {
michael@0:         var maxPermuteFallthrough = (1 << matchVals.length) - 1;
michael@0: 
michael@0:         for(var ft_pm = 0; ft_pm <= maxPermuteFallthrough; ft_pm++) {
michael@0:             // use bod_m and ft_pm to decide the placement of null vs value bodies,
michael@0:             // and the placement of fallthroughs vs breaks.
michael@0:             // Empty bodies always fall through, so fallthrough bitmask 1s must be
michael@0:             // a subset of the body bitmask 1s.
michael@0:             if((bod_pm | ft_pm) != bod_pm) {
michael@0:                 continue;
michael@0:             }
michael@0: 
michael@0:             var spec = [];
michael@0:             for(var k = 0; k < matchVals.length; k++) {
michael@0:                 var match = matchVals[k];
michael@0:                 var body = ((bod_pm & (1 << k)) > 0) ? null : RandVal();
michael@0:                 var fallthrough = ((ft_pm & (1 << k)) > 0) ? true : false;
michael@0:                 var caseSpec = {'match':match, 'body':body, 'fallthrough':fallthrough};
michael@0:                 spec.push(caseSpec);
michael@0:             }
michael@0: 
michael@0:             // Variant specs for following cases:
michael@0: 
michael@0:             // Default with empty body, fallthrough
michael@0:             GenerateDefaultPermutes(spec, null, true, resultArray);
michael@0:             // Default with nonempty body, fallthrough
michael@0:             GenerateDefaultPermutes(spec, RandVal(), true, resultArray);
michael@0:             // Default with nonempty body, break
michael@0:             GenerateDefaultPermutes(spec, RandVal(), false, resultArray);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: function GenerateDefaultPermutes(spec, body, fallthrough, resultArray) {
michael@0:     if(spec.length <= 2) {
michael@0:         for(var i = 0; i <= spec.length; i++) {
michael@0:             var copy = CopySpec(spec);
michael@0:             if(IsNull(body)) {
michael@0:                 copy.splice(i,0,{'match':null, 'body':null, 'fallthrough':true});
michael@0:             } else {
michael@0:                 copy.splice(i,0,{'match':null, 'body':body, 'fallthrough':fallthrough});
michael@0:             }
michael@0:             resultArray.push(copy);
michael@0:         }
michael@0:     } else {
michael@0:         var posns = [0, Math.floor(spec.length / 2), spec.length];
michael@0:         posns.forEach(function (i) {
michael@0:             var copy = CopySpec(spec);
michael@0:             if(IsNull(body)) {
michael@0:                 copy.splice(i,0,{'match':null, 'body':null, 'fallthrough':true});
michael@0:             } else {
michael@0:                 copy.splice(i,0,{'match':null, 'body':body, 'fallthrough':fallthrough});
michael@0:             }
michael@0:             resultArray.push(copy);
michael@0:         });
michael@0:     }
michael@0: }
michael@0: function CopySpec(spec) {
michael@0:     var newSpec = [];
michael@0:     for(var i = 0; i < spec.length; i++) {
michael@0:         var caseSpec = spec[i];
michael@0:         newSpec.push({'match':caseSpec.match,
michael@0:                       'body':caseSpec.body,
michael@0:                       'fallthrough':caseSpec.fallthrough});
michael@0:     }
michael@0:     return newSpec;
michael@0: }
michael@0: 
michael@0: 
michael@0: function RunSpec(spec, matchVals) {
michael@0:     var code = GenerateSwitchCode(spec);
michael@0: 
michael@0:     // Generate roughly 200 inputs for the test case spec, exercising
michael@0:     // every match value, as well as 3 randomly generated values for every
michael@0:     // iteration of the match values.
michael@0:     var inputs = [];
michael@0:     while(inputs.length < 500) {
michael@0:         for(var i = 0; i < matchVals.length; i++) { inputs.push(matchVals[i]); }
michael@0:         for(var i = 0; i < 3; i++) { inputs.push(RandVal()); }
michael@0:     }
michael@0: 
michael@0:     // Interpret the lookupswitch with the inputs.
michael@0:     var interpResults = [];
michael@0:     for(var i = 0; i < inputs.length; i++) {
michael@0:         InterpretSwitch(spec, inputs[i], interpResults);
michael@0:     }
michael@0: 
michael@0:     // Run compiled lookupswitch with the inputs.
michael@0:     var fn = eval("_ = " + code);
michael@0:     print("Running spec: " + code);
michael@0:     var compileResults = RunCompiled(fn, inputs);
michael@0:     print("Done Running spec");
michael@0: 
michael@0:     // Verify that they produce the same output.
michael@0:     ASSERT(interpResults.length == compileResults.length, "Length mismatch");
michael@0:     for(var i = 0; i < interpResults.length; i++) {
michael@0:         ASSERT(interpResults[i] == compileResults[i], "Value mismatch");
michael@0:     }
michael@0: }
michael@0: function RunCompiled(fn, inputs) {
michael@0:     var results = [];
michael@0:     var len = inputs.length;
michael@0:     for(var i = 0; i < len; i++) { fn(inputs[i], results); }
michael@0:     return results;
michael@0: }
michael@0: 
michael@0: function PrintSpec(spec, inputs, fname) {
michael@0:     var code = GenerateSwitchCode(spec, fname);
michael@0:     var input_s = fname + ".INPUTS = [" + inputs.map(Repr).join(', ') + "];";
michael@0:     var spec_s = fname + ".SPEC = " + JSON.stringify(spec) + ";";
michael@0:     print(code + "\n" + input_s + "\n" + spec_s);
michael@0: }
michael@0: 
michael@0: function RunTest(test) {
michael@0:     // Exercise every test case as well as one case which won't match with any of the
michael@0:     // ("But what if it randomly generates a string case match whose value is
michael@0:     //   UNMATCHED_CASE?!", you ask incredulously.  Well, RandStr limits itself to 11 chars.
michael@0:     //   So there.)
michael@0:     var inputs = test.INPUTS;
michael@0:     inputs.push("UNMATCHED_CASE");
michael@0:     var spec = test.SPEC;
michael@0: 
michael@0:     var results1 = [];
michael@0:     for(var i = 0; i < 80; i++) {
michael@0:         for(var j = 0; j < inputs.length; j++) {
michael@0:             test(inputs[j], results1);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     var results2 = [];
michael@0:     for(var i = 0; i < 80; i++) {
michael@0:         for(var j = 0; j < inputs.length; j++) {
michael@0:             InterpretSwitch(spec, inputs[j], results2);
michael@0:         }
michael@0:     }
michael@0:     ArraysEqual(results1, results2);
michael@0: }
michael@0: 
michael@0: // NOTES:
michael@0: //  * RunTest is used within the generated test script.
michael@0: //  * InterpretSwitch is printed out into the generated test script.
michael@0: 
michael@0: print("/////////////////////////////////////////");
michael@0: print("// This is a generated file!");
michael@0: print("// See jit-tests/etc/generate-lookupswitch-tests.js for the code");
michael@0: print("// that generated this code!");
michael@0: print("/////////////////////////////////////////");
michael@0: print("");
michael@0: print("/////////////////////////////////////////");
michael@0: print("// PRELUDE                             //");
michael@0: print("/////////////////////////////////////////");
michael@0: print("");
michael@0: print("// Avoid eager compilation of the global-scope.");
michael@0: print("try{} catch (x) {};");
michael@0: print("");
michael@0: print(ASSERT);
michael@0: print(IsNull);
michael@0: print(IsNum);
michael@0: print(ArraysEqual);
michael@0: print(InterpretSwitch);
michael@0: print(RunTest);
michael@0: print("");
michael@0: print("/////////////////////////////////////////");
michael@0: print("// TEST CASES                          //");
michael@0: print("/////////////////////////////////////////");
michael@0: print("");
michael@0: print("var TESTS = [];");
michael@0: var MATCH_SETS = [["foo", "bar", "zing"]];
michael@0: var count = 0;
michael@0: for(var i = 0; i < MATCH_SETS.length; i++) {
michael@0:     var matchSet = MATCH_SETS[i];
michael@0:     var specs = [];
michael@0:     GenerateSpecPermutes(matchSet, specs);
michael@0:     for(var j = 0; j < specs.length; j++) {
michael@0:         count++;
michael@0:         PrintSpec(specs[j], matchSet.slice(), 'test_'+count);
michael@0:         print("TESTS.push(test_"+count+");\n");
michael@0:     }
michael@0: }
michael@0: 
michael@0: print("");
michael@0: print("/////////////////////////////////////////");
michael@0: print("// RUNNER                              //");
michael@0: print("/////////////////////////////////////////");
michael@0: print("");
michael@0: print("for(var i = 0; i < TESTS.length; i++) {");
michael@0: print("  RunTest(TESTS[i]);");
michael@0: print("}");