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usr / src / contrib / llvm-project / clang / lib / StaticAnalyzer / Checkers /

📁 ..
📄 AllocationState.h(1.41 KB)
📄 AnalysisOrderChecker.cpp(8.62 KB)
📄 AnalyzerStatsChecker.cpp(5.04 KB)
📄 ArrayBoundChecker.cpp(3.22 KB)
📄 ArrayBoundCheckerV2.cpp(13.07 KB)
📄 BasicObjCFoundationChecks.cpp(43.82 KB)
📄 BlockInCriticalSectionChecker.cpp(6.69 KB)
📄 BoolAssignmentChecker.cpp(3.45 KB)
📄 BuiltinFunctionChecker.cpp(5 KB)
📄 CStringChecker.cpp(93.24 KB)
📄 CStringSyntaxChecker.cpp(9.8 KB)
📄 CXXSelfAssignmentChecker.cpp(3.08 KB)
📄 CallAndMessageChecker.cpp(26.57 KB)
📄 CastSizeChecker.cpp(4.96 KB)
📄 CastToStructChecker.cpp(4.43 KB)
📄 CastValueChecker.cpp(19.65 KB)
📄 CheckObjCDealloc.cpp(37.83 KB)
📄 CheckObjCInstMethSignature.cpp(4.8 KB)
📄 CheckPlacementNew.cpp(11.91 KB)
📄 CheckSecuritySyntaxOnly.cpp(38.79 KB)
📄 CheckSizeofPointer.cpp(3.16 KB)
📄 CheckerDocumentation.cpp(14.64 KB)
📄 ChrootChecker.cpp(4.88 KB)
📄 CloneChecker.cpp(8.28 KB)
📄 ContainerModeling.cpp(39.85 KB)
📄 ConversionChecker.cpp(7.11 KB)
📄 DeadStoresChecker.cpp(17.82 KB)
📄 DebugCheckers.cpp(10.41 KB)
📄 DebugContainerModeling.cpp(4.94 KB)
📄 DebugIteratorModeling.cpp(5.15 KB)
📄 DeleteWithNonVirtualDtorChecker.cpp(5.35 KB)
📄 DereferenceChecker.cpp(10.54 KB)
📄 DirectIvarAssignment.cpp(8.02 KB)
📄 DivZeroChecker.cpp(3.42 KB)
📄 DynamicTypeChecker.cpp(7.31 KB)
📄 DynamicTypePropagation.cpp(42.11 KB)
📄 EnumCastOutOfRangeChecker.cpp(5.75 KB)
📄 ExprInspectionChecker.cpp(15.6 KB)
📄 FixedAddressChecker.cpp(2.33 KB)
📄 FuchsiaHandleChecker.cpp(23.1 KB)
📄 GCDAntipatternChecker.cpp(7.85 KB)
📄 GTestChecker.cpp(10.52 KB)
📄 GenericTaintChecker.cpp(34.31 KB)
📄 IdenticalExprChecker.cpp(18.88 KB)
📄 InnerPointerChecker.cpp(11.54 KB)
📄 InterCheckerAPI.h(1.09 KB)
📄 InvalidatedIteratorChecker.cpp(4.93 KB)
📄 Iterator.cpp(10.62 KB)
📄 Iterator.h(6.32 KB)
📄 IteratorModeling.cpp(31.33 KB)
📄 IteratorRangeChecker.cpp(12.64 KB)
📄 IvarInvalidationChecker.cpp(27.63 KB)
📄 LLVMConventionsChecker.cpp(9.9 KB)
📄 LocalizationChecker.cpp(52.38 KB)
📄 MIGChecker.cpp(11.3 KB)
📁 MPI-Checker
📄 MacOSKeychainAPIChecker.cpp(25.21 KB)
📄 MacOSXAPIChecker.cpp(6.61 KB)
📄 MallocChecker.cpp(127.38 KB)
📄 MallocOverflowSecurityChecker.cpp(11.91 KB)
📄 MallocSizeofChecker.cpp(8.03 KB)
📄 MismatchedIteratorChecker.cpp(11.01 KB)
📄 MmapWriteExecChecker.cpp(3.22 KB)
📄 Move.h(1.07 KB)
📄 MoveChecker.cpp(27 KB)
📄 NSAutoreleasePoolChecker.cpp(2.93 KB)
📄 NSErrorChecker.cpp(10.6 KB)
📄 NoReturnFunctionChecker.cpp(5.48 KB)
📄 NonNullParamChecker.cpp(11.22 KB)
📄 NonnullGlobalConstantsChecker.cpp(5.09 KB)
📄 NullabilityChecker.cpp(46.95 KB)
📄 NumberObjectConversionChecker.cpp(13.69 KB)
📄 OSObjectCStyleCast.cpp(3.14 KB)
📄 ObjCAtSyncChecker.cpp(3.34 KB)
📄 ObjCAutoreleaseWriteChecker.cpp(8.62 KB)
📄 ObjCContainersASTChecker.cpp(5.5 KB)
📄 ObjCContainersChecker.cpp(6.71 KB)
📄 ObjCMissingSuperCallChecker.cpp(9.23 KB)
📄 ObjCPropertyChecker.cpp(3.03 KB)
📄 ObjCSelfInitChecker.cpp(16.21 KB)
📄 ObjCSuperDeallocChecker.cpp(9.33 KB)
📄 ObjCUnusedIVarsChecker.cpp(6.01 KB)
📄 PaddingChecker.cpp(14.26 KB)
📄 PointerArithChecker.cpp(12.18 KB)
📄 PointerIterationChecker.cpp(3.79 KB)
📄 PointerSortingChecker.cpp(4.5 KB)
📄 PointerSubChecker.cpp(2.56 KB)
📄 PthreadLockChecker.cpp(28.42 KB)
📁 RetainCountChecker
📄 ReturnPointerRangeChecker.cpp(3.39 KB)
📄 ReturnUndefChecker.cpp(4.1 KB)
📄 ReturnValueChecker.cpp(5.79 KB)
📄 RunLoopAutoreleaseLeakChecker.cpp(7.2 KB)
📄 STLAlgorithmModeling.cpp(7 KB)
📄 SimpleStreamChecker.cpp(9.43 KB)
📄 SmartPtr.h(1.17 KB)
📄 SmartPtrChecker.cpp(2.68 KB)
📄 SmartPtrModeling.cpp(8.05 KB)
📄 StackAddrEscapeChecker.cpp(15 KB)
📄 StdLibraryFunctionsChecker.cpp(74.86 KB)
📄 StreamChecker.cpp(37.36 KB)
📄 Taint.cpp(9.04 KB)
📄 Taint.h(4.19 KB)
📄 TaintTesterChecker.cpp(2.17 KB)
📄 TestAfterDivZeroChecker.cpp(8.19 KB)
📄 TraversalChecker.cpp(4.38 KB)
📄 TrustNonnullChecker.cpp(9.12 KB)
📄 UndefBranchChecker.cpp(3.82 KB)
📄 UndefCapturedBlockVarChecker.cpp(3.64 KB)
📄 UndefResultChecker.cpp(7.19 KB)
📄 UndefinedArraySubscriptChecker.cpp(2.36 KB)
📄 UndefinedAssignmentChecker.cpp(3.74 KB)
📁 UninitializedObject
📄 UnixAPIChecker.cpp(18.05 KB)
📄 UnreachableCodeChecker.cpp(9.59 KB)
📄 VLASizeChecker.cpp(10.95 KB)
📄 ValistChecker.cpp(15.65 KB)
📄 VforkChecker.cpp(7.67 KB)
📄 VirtualCallChecker.cpp(8.11 KB)
📁 WebKit
📄 Yaml.h(2.06 KB)
📁 cert

Editing: GCDAntipatternChecker.cpp

//===- GCDAntipatternChecker.cpp ---------------------------------*- C++ -*-==//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines GCDAntipatternChecker which checks against a common
// antipattern when synchronous API is emulated from asynchronous callbacks
// using a semaphore:
//
//   dispatch_semaphore_t sema = dispatch_semaphore_create(0);
//
//   AnyCFunctionCall(^{
//     // code…
//     dispatch_semaphore_signal(sema);
//   })
//   dispatch_semaphore_wait(sema, *)
//
// Such code is a common performance problem, due to inability of GCD to
// properly handle QoS when a combination of queues and semaphores is used.
// Good code would either use asynchronous API (when available), or perform
// the necessary action in asynchronous callback.
//
// Currently, the check is performed using a simple heuristical AST pattern
// matching.
//
//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
#include "llvm/Support/Debug.h"

using namespace clang;
using namespace ento;
using namespace ast_matchers;

namespace {

// ID of a node at which the diagnostic would be emitted.
const char *WarnAtNode = "waitcall";

class GCDAntipatternChecker : public Checker<check::ASTCodeBody> {
public:
  void checkASTCodeBody(const Decl *D,
                        AnalysisManager &AM,
                        BugReporter &BR) const;
};

decltype(auto) callsName(const char *FunctionName) {
  return callee(functionDecl(hasName(FunctionName)));
}

decltype(auto) equalsBoundArgDecl(int ArgIdx, const char *DeclName) {
  return hasArgument(ArgIdx, ignoringParenCasts(declRefExpr(
                                 to(varDecl(equalsBoundNode(DeclName))))));
}

decltype(auto) bindAssignmentToDecl(const char *DeclName) {
  return hasLHS(ignoringParenImpCasts(
                         declRefExpr(to(varDecl().bind(DeclName)))));
}

/// The pattern is very common in tests, and it is OK to use it there.
/// We have to heuristics for detecting tests: method name starts with "test"
/// (used in XCTest), and a class name contains "mock" or "test" (used in
/// helpers which are not tests themselves, but used exclusively in tests).
static bool isTest(const Decl *D) {
  if (const auto* ND = dyn_cast<NamedDecl>(D)) {
    std::string DeclName = ND->getNameAsString();
    if (StringRef(DeclName).startswith("test"))
      return true;
  }
  if (const auto *OD = dyn_cast<ObjCMethodDecl>(D)) {
    if (const auto *CD = dyn_cast<ObjCContainerDecl>(OD->getParent())) {
      std::string ContainerName = CD->getNameAsString();
      StringRef CN(ContainerName);
      if (CN.contains_lower("test") || CN.contains_lower("mock"))
        return true;
    }
  }
  return false;
}

static auto findGCDAntiPatternWithSemaphore() -> decltype(compoundStmt()) {

const char *SemaphoreBinding = "semaphore_name";
  auto SemaphoreCreateM = callExpr(allOf(
      callsName("dispatch_semaphore_create"),
      hasArgument(0, ignoringParenCasts(integerLiteral(equals(0))))));

auto SemaphoreBindingM = anyOf(
      forEachDescendant(
          varDecl(hasDescendant(SemaphoreCreateM)).bind(SemaphoreBinding)),
      forEachDescendant(binaryOperator(bindAssignmentToDecl(SemaphoreBinding),
                     hasRHS(SemaphoreCreateM))));

auto HasBlockArgumentM = hasAnyArgument(hasType(
            hasCanonicalType(blockPointerType())
            ));

auto ArgCallsSignalM = hasAnyArgument(stmt(hasDescendant(callExpr(
          allOf(
              callsName("dispatch_semaphore_signal"),
              equalsBoundArgDecl(0, SemaphoreBinding)
              )))));

auto HasBlockAndCallsSignalM = allOf(HasBlockArgumentM, ArgCallsSignalM);

auto HasBlockCallingSignalM =
    forEachDescendant(
      stmt(anyOf(
        callExpr(HasBlockAndCallsSignalM),
        objcMessageExpr(HasBlockAndCallsSignalM)
           )));

auto SemaphoreWaitM = forEachDescendant(
    callExpr(
      allOf(
        callsName("dispatch_semaphore_wait"),
        equalsBoundArgDecl(0, SemaphoreBinding)
      )
    ).bind(WarnAtNode));

return compoundStmt(
      SemaphoreBindingM, HasBlockCallingSignalM, SemaphoreWaitM);
}

static auto findGCDAntiPatternWithGroup() -> decltype(compoundStmt()) {

const char *GroupBinding = "group_name";
  auto DispatchGroupCreateM = callExpr(callsName("dispatch_group_create"));

auto GroupBindingM = anyOf(
      forEachDescendant(
          varDecl(hasDescendant(DispatchGroupCreateM)).bind(GroupBinding)),
      forEachDescendant(binaryOperator(bindAssignmentToDecl(GroupBinding),
                     hasRHS(DispatchGroupCreateM))));

auto GroupEnterM = forEachDescendant(
      stmt(callExpr(allOf(callsName("dispatch_group_enter"),
                          equalsBoundArgDecl(0, GroupBinding)))));

auto HasBlockArgumentM = hasAnyArgument(hasType(
            hasCanonicalType(blockPointerType())
            ));

auto ArgCallsSignalM = hasAnyArgument(stmt(hasDescendant(callExpr(
          allOf(
              callsName("dispatch_group_leave"),
              equalsBoundArgDecl(0, GroupBinding)
              )))));

auto HasBlockAndCallsLeaveM = allOf(HasBlockArgumentM, ArgCallsSignalM);

auto AcceptsBlockM =
    forEachDescendant(
      stmt(anyOf(
        callExpr(HasBlockAndCallsLeaveM),
        objcMessageExpr(HasBlockAndCallsLeaveM)
           )));

auto GroupWaitM = forEachDescendant(
    callExpr(
      allOf(
        callsName("dispatch_group_wait"),
        equalsBoundArgDecl(0, GroupBinding)
      )
    ).bind(WarnAtNode));

return compoundStmt(GroupBindingM, GroupEnterM, AcceptsBlockM, GroupWaitM);
}

static void emitDiagnostics(const BoundNodes &Nodes,
                            const char* Type,
                            BugReporter &BR,
                            AnalysisDeclContext *ADC,
                            const GCDAntipatternChecker *Checker) {
  const auto *SW = Nodes.getNodeAs<CallExpr>(WarnAtNode);
  assert(SW);

std::string Diagnostics;
  llvm::raw_string_ostream OS(Diagnostics);
  OS << "Waiting on a callback using a " << Type << " creates useless threads "
     << "and is subject to priority inversion; consider "
     << "using a synchronous API or changing the caller to be asynchronous";

BR.EmitBasicReport(
    ADC->getDecl(),
    Checker,
    /*Name=*/"GCD performance anti-pattern",
    /*BugCategory=*/"Performance",
    OS.str(),
    PathDiagnosticLocation::createBegin(SW, BR.getSourceManager(), ADC),
    SW->getSourceRange());
}

void GCDAntipatternChecker::checkASTCodeBody(const Decl *D,
                                             AnalysisManager &AM,
                                             BugReporter &BR) const {
  if (isTest(D))
    return;

AnalysisDeclContext *ADC = AM.getAnalysisDeclContext(D);

auto SemaphoreMatcherM = findGCDAntiPatternWithSemaphore();
  auto Matches = match(SemaphoreMatcherM, *D->getBody(), AM.getASTContext());
  for (BoundNodes Match : Matches)
    emitDiagnostics(Match, "semaphore", BR, ADC, this);

auto GroupMatcherM = findGCDAntiPatternWithGroup();
  Matches = match(GroupMatcherM, *D->getBody(), AM.getASTContext());
  for (BoundNodes Match : Matches)
    emitDiagnostics(Match, "group", BR, ADC, this);
}

} // end of anonymous namespace

void ento::registerGCDAntipattern(CheckerManager &Mgr) {
  Mgr.registerChecker<GCDAntipatternChecker>();
}

bool ento::shouldRegisterGCDAntipattern(const CheckerManager &mgr) {
  return true;
}

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Editing: GCDAntipatternChecker.cpp

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