Linter Demo

Errors: 6

Warnings: 8

File: /home/fstrocco/Dart/dart/benchmark/compiler/lib/src/tree_ir/tree_ir_integrity.dart

library tree_ir.integrity; import 'tree_ir_nodes.dart'; /// Performs integrity checks on the tree_ir. /// /// Should only be run for debugging purposes, not in production. /// /// - Reference counts on must match the actual number of references. /// - Labels must be in scope when referenced. /// - Breaks must target a [LabeledStatement]. /// - Continues must target a [Loop]. /// - Variables must only be used after their first assignment /// (checked on a best-effort basis). /// - Variables with a declaration must only be referenced in scope. /// - Variables must not have more than one declaration. /// class CheckTreeIntegrity extends RecursiveVisitor { RootNode topLevelNode; Map<Variable, int> varReads = <Variable, int>{}; Map<Variable, int> varWrites = <Variable, int>{}; Map<Label, int> labelUses = <Label, int>{}; Map<Label, JumpTarget> label2declaration = <Label, JumpTarget>{}; /// Variables that are currently in scope. Set<Variable> scope = new Set<Variable>(); /// Variables for which we have seen a declaration. Set<Variable> seenDeclaration = new Set<Variable>(); void write(Variable variable) { if (!seenDeclaration.contains(variable)) { // Implicitly-declared variables are in scope after the first assignment. scope.add(variable); } else if (!scope.contains(variable)) { // There is a declaration for variable but it is no longer in scope. error('$variable assigned out of scope'); } varWrites.putIfAbsent(variable, () => 0); varWrites[variable]++; } void read(Variable variable) { if (!scope.contains(variable)) { error('$variable used out of scope'); } varReads.putIfAbsent(variable, () => 0); varReads[variable]++; } void declare(Variable variable) { if (!scope.add(variable) || !seenDeclaration.add(variable)) { error('Redeclared $variable'); } varWrites.putIfAbsent(variable, () => 0); varWrites[variable]++; } void undeclare(Variable variable) { scope.remove(variable); } visitVariableUse(VariableUse node) { read(node.variable); } visitAssign(Assign node) { visitExpression(node.value); if (node.isDeclaration) { declare(node.variable); } else { write(node.variable); } visitStatement(node.next); if (node.isDeclaration) { undeclare(node.variable); } } visitTry(Try node) { visitStatement(node.tryBody); node.catchParameters.forEach(declare); visitStatement(node.catchBody); node.catchParameters.forEach(undeclare); } visitFunctionDeclaration(FunctionDeclaration node) { declare(node.variable); checkBody(node.definition); visitStatement(node.next); undeclare(node.variable); if (varWrites[node.variable] > 1) { error('Assignment to function declaration ${node.variable}'); } } visitJumpTargetBody(JumpTarget target) { Label label = target.label; if (label2declaration.containsKey(label)) { error('Duplicate declaration of label $label'); } label2declaration[label] = target; labelUses[label] = 0; visitStatement(target.body); label2declaration.remove(target); if (labelUses[label] != label.useCount) { error('Label $label has ${labelUses[label]} uses ' 'but its reference count is ${label.useCount}'); } } visitLabeledStatement(LabeledStatement node) { visitJumpTargetBody(node); visitStatement(node.next); } visitWhileTrue(WhileTrue node) { visitJumpTargetBody(node); } visitWhileCondition(WhileCondition node) { visitExpression(node.condition); visitJumpTargetBody(node); visitStatement(node.next); } visitBreak(Break node) { if (!label2declaration.containsKey(node.target)) { error('Break to label that is not in scope'); } if (label2declaration[node.target] is! LabeledStatement) { error('Break to non-labeled statement ${label2declaration[node.target]}'); } labelUses[node.target]++; } visitContinue(Continue node) { if (!label2declaration.containsKey(node.target)) { error('Continue to label that is not in scope'); } if (label2declaration[node.target] is! Loop) { error('Continue to non-loop statement ${label2declaration[node.target]}'); } labelUses[node.target]++; } visitInnerFunction(FunctionDefinition node) { checkBody(node); } void checkBody(RootNode node) { node.parameters.forEach(declare); node.forEachBody(visitStatement); node.parameters.forEach(undeclare); } dynamic error(String message) { throw 'Tree IR integrity violation in ${topLevelNode.element}:\n$message'; } void check(RootNode node) { topLevelNode = node; checkBody(node); // Verify reference counters for all variables. List<Variable> seenVariables = new List<Variable>(); seenVariables.addAll(varReads.keys); seenVariables.addAll(varWrites.keys); for (Variable variable in seenVariables) { int reads = varReads.putIfAbsent(variable, () => 0); int writes = varWrites.putIfAbsent(variable, () => 0); if (reads != variable.readCount || writes != variable.writeCount) { error('Invalid reference count for $variable:\n' '- Variable has $reads reads and $writes writes\n' '- Reference count is ${variable.readCount} reads and ' '${variable.writeCount} writes'); } } } }