UnsafeBufferUsageExtractor.cpp

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//===- UnsafeBufferUsageExtractor.cpp -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#include "SSAFAnalysesCommon.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DynamicRecursiveASTVisitor.h"
#include "clang/Analysis/Analyses/UnsafeBufferUsage.h"
#include "clang/Frontend/SSAFOptions.h"
#include "clang/ScalableStaticAnalysis/Analyses/EntityPointerLevel/EntityPointerLevel.h"
#include "clang/ScalableStaticAnalysis/Analyses/UnsafeBufferUsage/UnsafeBufferUsage.h"
#include "clang/ScalableStaticAnalysis/Core/TUSummary/ExtractorRegistry.h"
#include "clang/ScalableStaticAnalysis/Core/TUSummary/TUSummaryBuilder.h"
#include "clang/ScalableStaticAnalysis/Core/TUSummary/TUSummaryExtractor.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/Support/ErrorHandling.h"
#include <memory>
 
using namespace clang;
using namespace ssaf;
 
namespace clang::ssaf {
class UnsafeBufferUsageTUSummaryExtractor : public TUSummaryExtractor {
public:
  UnsafeBufferUsageTUSummaryExtractor(TUSummaryBuilder &Builder)
      : TUSummaryExtractor(Builder) {}
 
  /// \return a non-null unique pointer to a UnsafeBufferUsageEntitySummary
  std::unique_ptr<UnsafeBufferUsageEntitySummary>
  extractEntitySummary(const std::vector<const NamedDecl *> &ContributorDecls,
                       ASTContext &Ctx);
  void HandleTranslationUnit(ASTContext &Ctx) override;
};
} // namespace clang::ssaf
 
std::unique_ptr<UnsafeBufferUsageEntitySummary>
clang::ssaf::UnsafeBufferUsageTUSummaryExtractor::extractEntitySummary(
    const std::vector<const NamedDecl *> &ContributorDecls, ASTContext &Ctx) {
  std::set<const Expr *> UnsafePointers;
  auto MatchAction = [&UnsafePointers, &Ctx](const DynTypedNode &Node) {
    matchUnsafePointers(Node, Ctx, UnsafePointers);
  };
 
  for (const auto *Contrib : ContributorDecls)
    findMatchesIn(Contrib, MatchAction);
 
  EntityPointerLevelSet Results;
 
  for (const Expr *Ptr : UnsafePointers) {
    Expected<EntityPointerLevelSet> Translation =
        translateEntityPointerLevel(Ptr, Ctx, *this);
 
    if (Translation) {
      // Filter out those temporary invalid EntityPointerLevels associated
      // with `&E` pointers. They need no transformation of entities:
      auto FilteredTranslation = llvm::make_filter_range(
          *Translation, [](const EntityPointerLevel &E) -> bool {
            return E.getPointerLevel() > 0;
          });
      Results.insert(FilteredTranslation.begin(), FilteredTranslation.end());
      continue;
    }
    logWarningFromError(Translation.takeError());
  }
 
  return std::make_unique<UnsafeBufferUsageEntitySummary>(
      UnsafeBufferUsageEntitySummary(std::move(Results)));
}
 
void clang::ssaf::UnsafeBufferUsageTUSummaryExtractor::HandleTranslationUnit(
    ASTContext &Ctx) {
  extractAndAddSummaries(
      *this, SummaryBuilder, Ctx,
      [&](const std::vector<const NamedDecl *> &Decls) {
        return extractEntitySummary(Decls, Ctx);
      },
      "UnsafeBufferUsage");
}
namespace clang::ssaf {
// NOLINTNEXTLINE(misc-use-internal-linkage)
volatile int UnsafeBufferUsageExtractorAnchorSource = 0;
} // namespace clang::ssaf
 
static clang::ssaf::TUSummaryExtractorRegistry::Add<
    UnsafeBufferUsageTUSummaryExtractor>
    RegisterExtractor(UnsafeBufferUsageEntitySummary::Name,
                      "Extract unsafe buffer pointers");