Coverage Report

Created: 2021-08-24 07:12

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Analysis/Analyses/CalledOnceCheck.h
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//===- CalledOnceCheck.h - Check 'called once' parameters -------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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//  This file defines a check for function-like parameters that should be
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//  called exactly one time.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_CALLEDONCECHECK_H
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#define LLVM_CLANG_ANALYSIS_ANALYSES_CALLEDONCECHECK_H
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namespace clang {
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class AnalysisDeclContext;
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class BlockDecl;
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class CFG;
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class Decl;
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class DeclContext;
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class Expr;
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class ParmVarDecl;
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class Stmt;
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/// Classification of situations when parameter is not called on every path.
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/// \enum IfThen -- then branch of the if statement has no call.
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/// \enum IfElse -- else branch of the if statement has no call.
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/// \enum Switch -- one of the switch cases doesn't have a call.
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/// \enum SwitchSkipped -- there is no call if none of the cases appies.
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/// \enum LoopEntered -- no call when the loop is entered.
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/// \enum LoopSkipped -- no call when the loop is not entered.
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/// \enum FallbackReason -- fallback case when we were not able to figure out
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/// the reason.
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enum class NeverCalledReason {
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  IfThen,
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  IfElse,
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  Switch,
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  SwitchSkipped,
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  LoopEntered,
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  LoopSkipped,
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  FallbackReason,
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  LARGEST_VALUE = FallbackReason
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};
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class CalledOnceCheckHandler {
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public:
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  CalledOnceCheckHandler() = default;
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  virtual ~CalledOnceCheckHandler() = default;
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  /// Called when parameter is called twice.
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  /// \param Parameter -- parameter that should be called once.
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  /// \param Call -- call to report the warning.
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  /// \param PrevCall -- previous call.
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  /// \param IsCompletionHandler -- true, if parameter is a completion handler.
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  /// \param Poised -- true, if the second call is guaranteed to happen after
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  /// the first call.
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  virtual void handleDoubleCall(const ParmVarDecl *Parameter, const Expr *Call,
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                                const Expr *PrevCall, bool IsCompletionHandler,
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                                bool Poised) {}
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  /// Called when parameter is not called at all.
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  /// \param Parameter -- parameter that should be called once.
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  /// \param IsCompletionHandler -- true, if parameter is a completion handler.
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  virtual void handleNeverCalled(const ParmVarDecl *Parameter,
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                                 bool IsCompletionHandler) {}
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  /// Called when captured parameter is not called at all.
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  /// \param Parameter -- parameter that should be called once.
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  /// \param Where -- declaration that captures \p Parameter
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  /// \param IsCompletionHandler -- true, if parameter is a completion handler.
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  virtual void handleCapturedNeverCalled(const ParmVarDecl *Parameter,
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                                         const Decl *Where,
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                                         bool IsCompletionHandler) {}
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  /// Called when parameter is not called on one of the paths.
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  /// Usually we try to find a statement that is the least common ancestor of
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  /// the path containing the call and not containing the call.  This helps us
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  /// to pinpoint a bad path for the user.
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  /// \param Parameter -- parameter that should be called once.
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  /// \param Function -- function declaration where the problem occured.
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  /// \param Where -- the least common ancestor statement.
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  /// \param Reason -- a reason describing the path without a call.
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  /// \param IsCalledDirectly -- true, if parameter actually gets called on
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  /// the other path.  It is opposed to be used in some other way (added to some
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  /// collection, passed as a parameter, etc.).
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  /// \param IsCompletionHandler -- true, if parameter is a completion handler.
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  virtual void handleNeverCalled(const ParmVarDecl *Parameter,
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                                 const Decl *Function, const Stmt *Where,
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                                 NeverCalledReason Reason,
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                                 bool IsCalledDirectly,
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                                 bool IsCompletionHandler) {}
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  /// Called when the block is guaranteed to be called exactly once.
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  /// It means that we can be stricter with what we report on that block.
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  /// \param Block -- block declaration that is known to be called exactly once.
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  virtual void
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  handleBlockThatIsGuaranteedToBeCalledOnce(const BlockDecl *Block) {}
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  /// Called when the block has no guarantees about how many times it can get
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  /// called.
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  /// It means that we should be more lenient with reporting warnings in it.
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  /// \param Block -- block declaration in question.
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  virtual void handleBlockWithNoGuarantees(const BlockDecl *Block) {}
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};
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/// Check given CFG for 'called once' parameter violations.
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///
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/// It traverses the function and tracks how such parameters are used.
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/// It detects two main violations:
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///   * parameter is called twice
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///   * parameter is not called
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///
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/// \param AC -- context.
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/// \param Handler -- a handler for found violations.
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/// \param CheckConventionalParameters -- true, if we want to check parameters
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/// not explicitly marked as 'called once', but having the same requirements
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/// according to conventions.
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void checkCalledOnceParameters(AnalysisDeclContext &AC,
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                               CalledOnceCheckHandler &Handler,
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                               bool CheckConventionalParameters);
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} // end namespace clang
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#endif /* LLVM_CLANG_ANALYSIS_ANALYSES_CALLEDONCECHECK_H */