105 lines
4.1 KiB
C++
105 lines
4.1 KiB
C++
//===-- UncheckedOptionalAccessModel.h --------------------------*- 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 dataflow analysis that detects unsafe uses of optional
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// values.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H
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#define CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H
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#include "clang/AST/ASTContext.h"
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#include "clang/Analysis/CFG.h"
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#include "clang/Analysis/FlowSensitive/CFGMatchSwitch.h"
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#include "clang/Analysis/FlowSensitive/CachedConstAccessorsLattice.h"
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#include "clang/Analysis/FlowSensitive/DataflowAnalysis.h"
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#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
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#include "clang/Analysis/FlowSensitive/MatchSwitch.h"
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#include "clang/Analysis/FlowSensitive/NoopLattice.h"
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#include "clang/Basic/SourceLocation.h"
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#include "llvm/ADT/SmallVector.h"
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namespace clang {
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namespace dataflow {
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// FIXME: Explore using an allowlist-approach, where constructs supported by the
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// analysis are always enabled and additional constructs are enabled through the
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// `Options`.
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struct UncheckedOptionalAccessModelOptions {
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/// In generating diagnostics, ignore optionals reachable through overloaded
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/// `operator*` or `operator->` (other than those of the optional type
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/// itself). The analysis does not equate the results of such calls, so it
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/// can't identify when their results are used safely (across calls),
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/// resulting in false positives in all such cases. Note: this option does not
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/// cover access through `operator[]`.
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///
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/// FIXME: we now cache and equate the result of const accessors
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/// that look like unique_ptr, have both `->` (returning a pointer type) and
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/// `*` (returning a reference type). This includes mixing `->` and
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/// `*` in a sequence of calls as long as the object is not modified. Once we
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/// are confident in this const accessor caching, we shouldn't need the
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/// IgnoreSmartPointerDereference option anymore.
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bool IgnoreSmartPointerDereference = false;
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/// In generating diagnostics, ignore calls to `optional::value()`.
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bool IgnoreValueCalls = false;
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};
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using UncheckedOptionalAccessLattice = CachedConstAccessorsLattice<NoopLattice>;
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/// Dataflow analysis that models whether optionals hold values or not.
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///
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/// Models the `std::optional`, `absl::optional`, and `base::Optional` types.
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class UncheckedOptionalAccessModel
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: public DataflowAnalysis<UncheckedOptionalAccessModel,
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UncheckedOptionalAccessLattice> {
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public:
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UncheckedOptionalAccessModel(ASTContext &Ctx, dataflow::Environment &Env);
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/// Returns a matcher for the optional classes covered by this model.
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static ast_matchers::DeclarationMatcher optionalClassDecl();
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static UncheckedOptionalAccessLattice initialElement() { return {}; }
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void transfer(const CFGElement &Elt, UncheckedOptionalAccessLattice &L,
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Environment &Env);
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private:
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CFGMatchSwitch<TransferState<UncheckedOptionalAccessLattice>>
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TransferMatchSwitch;
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};
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/// Diagnostic information for an unchecked optional access.
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struct UncheckedOptionalAccessDiagnostic {
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CharSourceRange Range;
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};
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class UncheckedOptionalAccessDiagnoser {
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public:
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UncheckedOptionalAccessDiagnoser(
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UncheckedOptionalAccessModelOptions Options = {});
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llvm::SmallVector<UncheckedOptionalAccessDiagnostic>
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operator()(const CFGElement &Elt, ASTContext &Ctx,
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const TransferStateForDiagnostics<UncheckedOptionalAccessLattice>
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&State) {
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return DiagnoseMatchSwitch(Elt, Ctx, State.Env);
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}
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private:
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CFGMatchSwitch<const Environment,
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llvm::SmallVector<UncheckedOptionalAccessDiagnostic>>
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DiagnoseMatchSwitch;
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};
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} // namespace dataflow
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} // namespace clang
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#endif // CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H
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