86 lines
2.2 KiB
D
86 lines
2.2 KiB
D
// Copyright Brian Schott (Hackerpilot) 2014.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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module dscanner.analysis.length_subtraction;
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import std.stdio;
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import dparse.ast;
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import dparse.lexer;
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import dscanner.analysis.base;
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import dscanner.analysis.helpers;
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import dsymbol.scope_;
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/**
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* Checks for subtraction from a .length property. This is usually a bug.
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*/
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final class LengthSubtractionCheck : BaseAnalyzer
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{
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private enum string KEY = "dscanner.suspicious.length_subtraction";
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alias visit = BaseAnalyzer.visit;
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mixin AnalyzerInfo!"length_subtraction_check";
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this(BaseAnalyzerArguments args)
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{
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super(args);
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}
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override void visit(const AddExpression addExpression)
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{
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if (addExpression.operator == tok!"-")
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{
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const UnaryExpression l = cast(const UnaryExpression) addExpression.left;
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const UnaryExpression r = cast(const UnaryExpression) addExpression.right;
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if (l is null || r is null)
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goto end;
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if (r.primaryExpression is null || r.primaryExpression.primary.type != tok!"intLiteral")
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goto end;
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if (l.identifierOrTemplateInstance is null
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|| l.identifierOrTemplateInstance.identifier.text != "length")
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goto end;
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addErrorMessage(addExpression, KEY,
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"Avoid subtracting from '.length' as it may be unsigned.",
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[
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AutoFix.insertionBefore(l.tokens[0], "cast(ptrdiff_t) ", "Cast to ptrdiff_t")
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]);
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}
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end:
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addExpression.accept(this);
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}
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}
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unittest
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{
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import dscanner.analysis.config : StaticAnalysisConfig, Check, disabledConfig;
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StaticAnalysisConfig sac = disabledConfig();
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sac.length_subtraction_check = Check.enabled;
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assertAnalyzerWarnings(q{
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void testSizeT()
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{
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if (i < a.length - 1) /+
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^^^^^^^^^^^^ [warn]: Avoid subtracting from '.length' as it may be unsigned. +/
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writeln("something");
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}
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}c, sac);
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assertAutoFix(q{
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void testSizeT()
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{
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if (i < a.length - 1) // fix
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writeln("something");
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}
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}c, q{
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void testSizeT()
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{
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if (i < cast(ptrdiff_t) a.length - 1) // fix
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writeln("something");
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}
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}c, sac);
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stderr.writeln("Unittest for IfElseSameCheck passed.");
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}
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