forked from OSchip/llvm-project
166 lines
7.0 KiB
C++
166 lines
7.0 KiB
C++
//===--- SimplifyBooleanExpr.h clang-tidy -----------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_SIMPLIFY_BOOLEAN_EXPR_H
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#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_SIMPLIFY_BOOLEAN_EXPR_H
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#include "../ClangTidy.h"
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namespace clang {
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namespace tidy {
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namespace readability {
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/// Looks for boolean expressions involving boolean constants and simplifies
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/// them to use the appropriate boolean expression directly.
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///
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/// Examples:
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///
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/// =========================================== ================
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/// Initial expression Result
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/// ------------------------------------------- ----------------
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/// `if (b == true)` `if (b)`
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/// `if (b == false)` `if (!b)`
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/// `if (b && true)` `if (b)`
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/// `if (b && false)` `if (false)`
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/// `if (b || true)` `if (true)`
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/// `if (b || false)` `if (b)`
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/// `e ? true : false` `e`
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/// `e ? false : true` `!e`
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/// `if (true) t(); else f();` `t();`
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/// `if (false) t(); else f();` `f();`
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/// `if (e) return true; else return false;` `return e;`
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/// `if (e) return false; else return true;` `return !e;`
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/// `if (e) b = true; else b = false;` `b = e;`
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/// `if (e) b = false; else b = true;` `b = !e;`
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/// `if (e) return true; return false;` `return e;`
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/// `if (e) return false; return true;` `return !e;`
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/// =========================================== ================
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///
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/// The resulting expression `e` is modified as follows:
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/// 1. Unnecessary parentheses around the expression are removed.
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/// 2. Negated applications of `!` are eliminated.
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/// 3. Negated applications of comparison operators are changed to use the
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/// opposite condition.
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/// 4. Implicit conversions of pointer to `bool` are replaced with explicit
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/// comparisons to `nullptr`.
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/// 5. Implicit casts to `bool` are replaced with explicit casts to `bool`.
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/// 6. Object expressions with `explicit operator bool` conversion operators
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/// are replaced with explicit casts to `bool`.
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///
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/// Examples:
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/// 1. The ternary assignment `bool b = (i < 0) ? true : false;` has redundant
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/// parentheses and becomes `bool b = i < 0;`.
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///
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/// 2. The conditional return `if (!b) return false; return true;` has an
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/// implied double negation and becomes `return b;`.
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///
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/// 3. The conditional return `if (i < 0) return false; return true;` becomes
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/// `return i >= 0;`.
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///
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/// The conditional return `if (i != 0) return false; return true;` becomes
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/// `return i == 0;`.
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///
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/// 4. The conditional return `if (p) return true; return false;` has an
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/// implicit conversion of a pointer to `bool` and becomes
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/// `return p != nullptr;`.
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///
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/// The ternary assignment `bool b = (i & 1) ? true : false;` has an
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/// implicit conversion of `i & 1` to `bool` and becomes
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/// `bool b = static_cast<bool>(i & 1);`.
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///
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/// 5. The conditional return `if (i & 1) return true; else return false;` has
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/// an implicit conversion of an integer quantity `i & 1` to `bool` and
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/// becomes `return static_cast<bool>(i & 1);`
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///
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/// 6. Given `struct X { explicit operator bool(); };`, and an instance `x` of
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/// `struct X`, the conditional return `if (x) return true; return false;`
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/// becomes `return static_cast<bool>(x);`
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///
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/// When a conditional boolean return or assignment appears at the end of a
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/// chain of `if`, `else if` statements, the conditional statement is left
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/// unchanged unless the option `ChainedConditionalReturn` or
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/// `ChainedConditionalAssignment`, respectively, is specified as non-zero.
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/// The default value for both options is zero.
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///
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class SimplifyBooleanExprCheck : public ClangTidyCheck {
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public:
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SimplifyBooleanExprCheck(StringRef Name, ClangTidyContext *Context);
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void storeOptions(ClangTidyOptions::OptionMap &Options) override;
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void registerMatchers(ast_matchers::MatchFinder *Finder) override;
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void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
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private:
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void matchBoolBinOpExpr(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef OperatorName, StringRef BooleanId);
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void matchExprBinOpBool(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef OperatorName, StringRef BooleanId);
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void matchBoolCompOpExpr(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef OperatorName, StringRef BooleanId);
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void matchExprCompOpBool(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef OperatorName, StringRef BooleanId);
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void matchBoolCondition(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef BooleanId);
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void matchTernaryResult(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef TernaryId);
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void matchIfReturnsBool(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef Id);
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void matchIfAssignsBool(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef Id);
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void matchCompoundIfReturnsBool(ast_matchers::MatchFinder *Finder, bool Value,
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StringRef Id);
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void
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replaceWithExpression(const ast_matchers::MatchFinder::MatchResult &Result,
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const CXXBoolLiteralExpr *BoolLiteral, bool UseLHS,
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bool Negated = false);
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void
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replaceWithThenStatement(const ast_matchers::MatchFinder::MatchResult &Result,
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const CXXBoolLiteralExpr *BoolLiteral);
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void
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replaceWithElseStatement(const ast_matchers::MatchFinder::MatchResult &Result,
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const CXXBoolLiteralExpr *FalseConditionRemoved);
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void
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replaceWithCondition(const ast_matchers::MatchFinder::MatchResult &Result,
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const ConditionalOperator *Ternary,
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bool Negated = false);
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void replaceWithReturnCondition(
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const ast_matchers::MatchFinder::MatchResult &Result, const IfStmt *If,
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bool Negated = false);
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void
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replaceWithAssignment(const ast_matchers::MatchFinder::MatchResult &Result,
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const IfStmt *If, bool Negated = false);
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void replaceCompoundReturnWithCondition(
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const ast_matchers::MatchFinder::MatchResult &Result,
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const CompoundStmt *Compound, bool Negated = false);
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const bool ChainedConditionalReturn;
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const bool ChainedConditionalAssignment;
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};
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} // namespace readability
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} // namespace tidy
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} // namespace clang
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#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_SIMPLIFY_BOOLEAN_EXPR_H
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