Google Git
Sign in
llvm / clang / 3f4b39141dfb8d13649da48635393e35e03054f3 / . / lib / StaticAnalyzer / Core / BugReporter.cpp
blob: 1864bcef9b8733619b5901541defb04c03e3b9d2 [file] [log] [blame]
//===- BugReporter.cpp - Generate PathDiagnostics for bugs ----------------===//
//
// 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 BugReporter, a utility class for generating
// PathDiagnostics.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Analysis/AnalysisDeclContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/CFGStmtMap.h"
#include "clang/Analysis/PathDiagnostic.h"
#include "clang/Analysis/ProgramPoint.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/StaticAnalyzer/Core/AnalyzerOptions.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <iterator>
#include <memory>
#include <queue>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace clang;
using namespace ento;
using namespace llvm;
#define DEBUG_TYPE "BugReporter"
STATISTIC(MaxBugClassSize,
"The maximum number of bug reports in the same equivalence class");
STATISTIC(MaxValidBugClassSize,
"The maximum number of bug reports in the same equivalence class "
"where at least one report is valid (not suppressed)");
BugReporterVisitor::~BugReporterVisitor() = default;
void BugReporterContext::anchor() {}
//===----------------------------------------------------------------------===//
// PathDiagnosticBuilder and its associated routines and helper objects.
//===----------------------------------------------------------------------===//
namespace {
/// A (CallPiece, node assiciated with its CallEnter) pair.
using CallWithEntry =
std::pair<PathDiagnosticCallPiece *, const ExplodedNode *>;
using CallWithEntryStack = SmallVector<CallWithEntry, 6>;
/// Map from each node to the diagnostic pieces visitors emit for them.
using VisitorsDiagnosticsTy =
llvm::DenseMap<const ExplodedNode *, std::vector<PathDiagnosticPieceRef>>;
/// A map from PathDiagnosticPiece to the LocationContext of the inlined
/// function call it represents.
using LocationContextMap =
llvm::DenseMap<const PathPieces *, const LocationContext *>;
/// A helper class that contains everything needed to construct a
/// PathDiagnostic object. It does no much more then providing convenient
/// getters and some well placed asserts for extra security.
class PathDiagnosticConstruct {
/// The consumer we're constructing the bug report for.
const PathDiagnosticConsumer *Consumer;
/// Our current position in the bug path, which is owned by
/// PathDiagnosticBuilder.
const ExplodedNode *CurrentNode;
/// A mapping from parts of the bug path (for example, a function call, which
/// would span backwards from a CallExit to a CallEnter with the nodes in
/// between them) with the location contexts it is associated with.
LocationContextMap LCM;
const SourceManager &SM;
public:
/// We keep stack of calls to functions as we're ascending the bug path.
/// TODO: PathDiagnostic has a stack doing the same thing, shouldn't we use
/// that instead?
CallWithEntryStack CallStack;
/// The bug report we're constructing. For ease of use, this field is kept
/// public, though some "shortcut" getters are provided for commonly used
/// methods of PathDiagnostic.
std::unique_ptr<PathDiagnostic> PD;
public:
PathDiagnosticConstruct(const PathDiagnosticConsumer *PDC,
const ExplodedNode *ErrorNode,
const PathSensitiveBugReport *R);
/// \returns the location context associated with the current position in the
/// bug path.
const LocationContext *getCurrLocationContext() const {
assert(CurrentNode && "Already reached the root!");
return CurrentNode->getLocationContext();
}
/// Same as getCurrLocationContext (they should always return the same
/// location context), but works after reaching the root of the bug path as
/// well.
const LocationContext *getLocationContextForActivePath() const {
return LCM.find(&PD->getActivePath())->getSecond();
}
const ExplodedNode *getCurrentNode() const { return CurrentNode; }
/// Steps the current node to its predecessor.
/// \returns whether we reached the root of the bug path.
bool ascendToPrevNode() {
CurrentNode = CurrentNode->getFirstPred();
return static_cast<bool>(CurrentNode);
}
const ParentMap &getParentMap() const {
return getCurrLocationContext()->getParentMap();
}
const SourceManager &getSourceManager() const { return SM; }
const Stmt *getParent(const Stmt *S) const {
return getParentMap().getParent(S);
}
void updateLocCtxMap(const PathPieces *Path, const LocationContext *LC) {
assert(Path && LC);
LCM[Path] = LC;
}
const LocationContext *getLocationContextFor(const PathPieces *Path) const {
assert(LCM.count(Path) &&
"Failed to find the context associated with these pieces!");
return LCM.find(Path)->getSecond();
}
bool isInLocCtxMap(const PathPieces *Path) const { return LCM.count(Path); }
PathPieces &getActivePath() { return PD->getActivePath(); }
PathPieces &getMutablePieces() { return PD->getMutablePieces(); }
bool shouldAddPathEdges() const { return Consumer->shouldAddPathEdges(); }
bool shouldGenerateDiagnostics() const {
return Consumer->shouldGenerateDiagnostics();
}
bool supportsLogicalOpControlFlow() const {
return Consumer->supportsLogicalOpControlFlow();
}
};
/// Contains every contextual information needed for constructing a
/// PathDiagnostic object for a given bug report. This class and its fields are
/// immutable, and passes a BugReportConstruct object around during the
/// construction.
class PathDiagnosticBuilder : public BugReporterContext {
/// A linear path from the error node to the root.
std::unique_ptr<const ExplodedGraph> BugPath;
/// The bug report we're describing. Visitors create their diagnostics with
/// them being the last entities being able to modify it (for example,
/// changing interestingness here would cause inconsistencies as to how this
/// file and visitors construct diagnostics), hence its const.
const PathSensitiveBugReport *R;
/// The leaf of the bug path. This isn't the same as the bug reports error
/// node, which refers to the *original* graph, not the bug path.
const ExplodedNode *const ErrorNode;
/// The diagnostic pieces visitors emitted, which is expected to be collected
/// by the time this builder is constructed.
std::unique_ptr<const VisitorsDiagnosticsTy> VisitorsDiagnostics;
public:
/// Find a non-invalidated report for a given equivalence class, and returns
/// a PathDiagnosticBuilder able to construct bug reports for different
/// consumers. Returns None if no valid report is found.
static Optional<PathDiagnosticBuilder>
findValidReport(ArrayRef<PathSensitiveBugReport *> &bugReports,
PathSensitiveBugReporter &Reporter);
PathDiagnosticBuilder(
BugReporterContext BRC, std::unique_ptr<ExplodedGraph> BugPath,
PathSensitiveBugReport *r, const ExplodedNode *ErrorNode,
std::unique_ptr<VisitorsDiagnosticsTy> VisitorsDiagnostics);
/// This function is responsible for generating diagnostic pieces that are
/// *not* provided by bug report visitors.
/// These diagnostics may differ depending on the consumer's settings,
/// and are therefore constructed separately for each consumer.
///
/// There are two path diagnostics generation modes: with adding edges (used
/// for plists) and without (used for HTML and text). When edges are added,
/// the path is modified to insert artificially generated edges.
/// Otherwise, more detailed diagnostics is emitted for block edges,
/// explaining the transitions in words.
std::unique_ptr<PathDiagnostic>
generate(const PathDiagnosticConsumer *PDC) const;
private:
void updateStackPiecesWithMessage(PathDiagnosticPieceRef P,
const CallWithEntryStack &CallStack) const;
void generatePathDiagnosticsForNode(PathDiagnosticConstruct &C,
PathDiagnosticLocation &PrevLoc) const;
void generateMinimalDiagForBlockEdge(PathDiagnosticConstruct &C,
BlockEdge BE) const;
PathDiagnosticPieceRef
generateDiagForGotoOP(const PathDiagnosticConstruct &C, const Stmt *S,
PathDiagnosticLocation &Start) const;
PathDiagnosticPieceRef
generateDiagForSwitchOP(const PathDiagnosticConstruct &C, const CFGBlock *Dst,
PathDiagnosticLocation &Start) const;
PathDiagnosticPieceRef
generateDiagForBinaryOP(const PathDiagnosticConstruct &C, const Stmt *T,
const CFGBlock *Src, const CFGBlock *DstC) const;
PathDiagnosticLocation
ExecutionContinues(const PathDiagnosticConstruct &C) const;
PathDiagnosticLocation
ExecutionContinues(llvm::raw_string_ostream &os,
const PathDiagnosticConstruct &C) const;
const PathSensitiveBugReport *getBugReport() const { return R; }
};
} // namespace
//===----------------------------------------------------------------------===//
// Base implementation of stack hint generators.
//===----------------------------------------------------------------------===//
StackHintGenerator::~StackHintGenerator() = default;
std::string StackHintGeneratorForSymbol::getMessage(const ExplodedNode *N){
if (!N)
return getMessageForSymbolNotFound();
ProgramPoint P = N->getLocation();
CallExitEnd CExit = P.castAs<CallExitEnd>();
// FIXME: Use CallEvent to abstract this over all calls.
const Stmt *CallSite = CExit.getCalleeContext()->getCallSite();
const auto *CE = dyn_cast_or_null<CallExpr>(CallSite);
if (!CE)
return {};
// Check if one of the parameters are set to the interesting symbol.
unsigned ArgIndex = 0;
for (CallExpr::const_arg_iterator I = CE->arg_begin(),
E = CE->arg_end(); I != E; ++I, ++ArgIndex){
SVal SV = N->getSVal(*I);
// Check if the variable corresponding to the symbol is passed by value.
SymbolRef AS = SV.getAsLocSymbol();
if (AS == Sym) {
return getMessageForArg(*I, ArgIndex);
}
// Check if the parameter is a pointer to the symbol.
if (Optional<loc::MemRegionVal> Reg = SV.getAs<loc::MemRegionVal>()) {
// Do not attempt to dereference void*.
if ((*I)->getType()->isVoidPointerType())
continue;
SVal PSV = N->getState()->getSVal(Reg->getRegion());
SymbolRef AS = PSV.getAsLocSymbol();
if (AS == Sym) {
return getMessageForArg(*I, ArgIndex);
}
}
}
// Check if we are returning the interesting symbol.
SVal SV = N->getSVal(CE);
SymbolRef RetSym = SV.getAsLocSymbol();
if (RetSym == Sym) {
return getMessageForReturn(CE);
}
return getMessageForSymbolNotFound();
}
std::string StackHintGeneratorForSymbol::getMessageForArg(const Expr *ArgE,
unsigned ArgIndex) {
// Printed parameters start at 1, not 0.
++ArgIndex;
return (llvm::Twine(Msg) + " via " + std::to_string(ArgIndex) +
llvm::getOrdinalSuffix(ArgIndex) + " parameter").str();
}
//===----------------------------------------------------------------------===//
// Diagnostic cleanup.
//===----------------------------------------------------------------------===//
static PathDiagnosticEventPiece *
eventsDescribeSameCondition(PathDiagnosticEventPiece *X,
PathDiagnosticEventPiece *Y) {
// Prefer diagnostics that come from ConditionBRVisitor over
// those that came from TrackConstraintBRVisitor,
// unless the one from ConditionBRVisitor is
// its generic fallback diagnostic.
const void *tagPreferred = ConditionBRVisitor::getTag();
const void *tagLesser = TrackConstraintBRVisitor::getTag();
if (X->getLocation() != Y->getLocation())
return nullptr;
if (X->getTag() == tagPreferred && Y->getTag() == tagLesser)
return ConditionBRVisitor::isPieceMessageGeneric(X) ? Y : X;
if (Y->getTag() == tagPreferred && X->getTag() == tagLesser)
return ConditionBRVisitor::isPieceMessageGeneric(Y) ? X : Y;
return nullptr;
}
/// An optimization pass over PathPieces that removes redundant diagnostics
/// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both
/// BugReporterVisitors use different methods to generate diagnostics, with
/// one capable of emitting diagnostics in some cases but not in others. This
/// can lead to redundant diagnostic pieces at the same point in a path.
static void removeRedundantMsgs(PathPieces &path) {
unsigned N = path.size();
if (N < 2)
return;
// NOTE: this loop intentionally is not using an iterator. Instead, we
// are streaming the path and modifying it in place. This is done by
// grabbing the front, processing it, and if we decide to keep it append
// it to the end of the path. The entire path is processed in this way.
for (unsigned i = 0; i < N; ++i) {
auto piece = std::move(path.front());
path.pop_front();
switch (piece->getKind()) {
case PathDiagnosticPiece::Call:
removeRedundantMsgs(cast<PathDiagnosticCallPiece>(*piece).path);
break;
case PathDiagnosticPiece::Macro:
removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(*piece).subPieces);
break;
case PathDiagnosticPiece::Event: {
if (i == N-1)
break;
if (auto *nextEvent =
dyn_cast<PathDiagnosticEventPiece>(path.front().get())) {
auto *event = cast<PathDiagnosticEventPiece>(piece.get());
// Check to see if we should keep one of the two pieces. If we
// come up with a preference, record which piece to keep, and consume
// another piece from the path.
if (auto *pieceToKeep =
eventsDescribeSameCondition(event, nextEvent)) {
piece = std::move(pieceToKeep == event ? piece : path.front());
path.pop_front();
++i;
}
}
break;
}
case PathDiagnosticPiece::ControlFlow:
case PathDiagnosticPiece::Note:
case PathDiagnosticPiece::PopUp:
break;
}
path.push_back(std::move(piece));
}
}
/// Recursively scan through a path and prune out calls and macros pieces
/// that aren't needed. Return true if afterwards the path contains
/// "interesting stuff" which means it shouldn't be pruned from the parent path.
static bool removeUnneededCalls(const PathDiagnosticConstruct &C,
PathPieces &pieces,
const PathSensitiveBugReport *R,
bool IsInteresting = false) {
bool containsSomethingInteresting = IsInteresting;
const unsigned N = pieces.size();
for (unsigned i = 0 ; i < N ; ++i) {
// Remove the front piece from the path. If it is still something we
// want to keep once we are done, we will push it back on the end.
auto piece = std::move(pieces.front());
pieces.pop_front();
switch (piece->getKind()) {
case PathDiagnosticPiece::Call: {
auto &call = cast<PathDiagnosticCallPiece>(*piece);
// Check if the location context is interesting.
if (!removeUnneededCalls(
C, call.path, R,
R->isInteresting(C.getLocationContextFor(&call.path))))
continue;
containsSomethingInteresting = true;
break;
}
case PathDiagnosticPiece::Macro: {
auto &macro = cast<PathDiagnosticMacroPiece>(*piece);
if (!removeUnneededCalls(C, macro.subPieces, R, IsInteresting))
continue;
containsSomethingInteresting = true;
break;
}
case PathDiagnosticPiece::Event: {
auto &event = cast<PathDiagnosticEventPiece>(*piece);
// We never throw away an event, but we do throw it away wholesale
// as part of a path if we throw the entire path away.
containsSomethingInteresting |= !event.isPrunable();
break;
}
case PathDiagnosticPiece::ControlFlow:
case PathDiagnosticPiece::Note:
case PathDiagnosticPiece::PopUp:
break;
}
pieces.push_back(std::move(piece));
}
return containsSomethingInteresting;
}
/// Same logic as above to remove extra pieces.
static void removePopUpNotes(PathPieces &Path) {
for (unsigned int i = 0; i < Path.size(); ++i) {
auto Piece = std::move(Path.front());
Path.pop_front();
if (!isa<PathDiagnosticPopUpPiece>(*Piece))
Path.push_back(std::move(Piece));
}
}
/// Returns true if the given decl has been implicitly given a body, either by
/// the analyzer or by the compiler proper.
static bool hasImplicitBody(const Decl *D) {
assert(D);
return D->isImplicit() || !D->hasBody();
}
/// Recursively scan through a path and make sure that all call pieces have
/// valid locations.
static void
adjustCallLocations(PathPieces &Pieces,
PathDiagnosticLocation *LastCallLocation = nullptr) {
for (const auto &I : Pieces) {
auto *Call = dyn_cast<PathDiagnosticCallPiece>(I.get());
if (!Call)
continue;
if (LastCallLocation) {
bool CallerIsImplicit = hasImplicitBody(Call->getCaller());
if (CallerIsImplicit || !Call->callEnter.asLocation().isValid())
Call->callEnter = *LastCallLocation;
if (CallerIsImplicit || !Call->callReturn.asLocation().isValid())
Call->callReturn = *LastCallLocation;
}
// Recursively clean out the subclass. Keep this call around if
// it contains any informative diagnostics.
PathDiagnosticLocation *ThisCallLocation;
if (Call->callEnterWithin.asLocation().isValid() &&
!hasImplicitBody(Call->getCallee()))
ThisCallLocation = &Call->callEnterWithin;
else
ThisCallLocation = &Call->callEnter;
assert(ThisCallLocation && "Outermost call has an invalid location");
adjustCallLocations(Call->path, ThisCallLocation);
}
}
/// Remove edges in and out of C++ default initializer expressions. These are
/// for fields that have in-class initializers, as opposed to being initialized
/// explicitly in a constructor or braced list.
static void removeEdgesToDefaultInitializers(PathPieces &Pieces) {
for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
removeEdgesToDefaultInitializers(C->path);
if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
removeEdgesToDefaultInitializers(M->subPieces);
if (auto *CF = dyn_cast<PathDiagnosticControlFlowPiece>(I->get())) {
const Stmt *Start = CF->getStartLocation().asStmt();
const Stmt *End = CF->getEndLocation().asStmt();
if (Start && isa<CXXDefaultInitExpr>(Start)) {
I = Pieces.erase(I);
continue;
} else if (End && isa<CXXDefaultInitExpr>(End)) {
PathPieces::iterator Next = std::next(I);
if (Next != E) {
if (auto *NextCF =
dyn_cast<PathDiagnosticControlFlowPiece>(Next->get())) {
NextCF->setStartLocation(CF->getStartLocation());
}
}
I = Pieces.erase(I);
continue;
}
}
I++;
}
}
/// Remove all pieces with invalid locations as these cannot be serialized.
/// We might have pieces with invalid locations as a result of inlining Body
/// Farm generated functions.
static void removePiecesWithInvalidLocations(PathPieces &Pieces) {
for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
removePiecesWithInvalidLocations(C->path);
if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
removePiecesWithInvalidLocations(M->subPieces);
if (!(*I)->getLocation().isValid() ||
!(*I)->getLocation().asLocation().isValid()) {
I = Pieces.erase(I);
continue;
}
I++;
}
}
PathDiagnosticLocation PathDiagnosticBuilder::ExecutionContinues(
const PathDiagnosticConstruct &C) const {
if (const Stmt *S = C.getCurrentNode()->getNextStmtForDiagnostics())
return PathDiagnosticLocation(S, getSourceManager(),
C.getCurrLocationContext());
return PathDiagnosticLocation::createDeclEnd(C.getCurrLocationContext(),
getSourceManager());
}
PathDiagnosticLocation PathDiagnosticBuilder::ExecutionContinues(
llvm::raw_string_ostream &os, const PathDiagnosticConstruct &C) const {
// Slow, but probably doesn't matter.
if (os.str().empty())
os << ' ';
const PathDiagnosticLocation &Loc = ExecutionContinues(C);
if (Loc.asStmt())
os << "Execution continues on line "
<< getSourceManager().getExpansionLineNumber(Loc.asLocation())
<< '.';
else {
os << "Execution jumps to the end of the ";
const Decl *D = C.getCurrLocationContext()->getDecl();
if (isa<ObjCMethodDecl>(D))
os << "method";
else if (isa<FunctionDecl>(D))
os << "function";
else {
assert(isa<BlockDecl>(D));
os << "anonymous block";
}
os << '.';
}
return Loc;
}
static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) {
if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
return PM.getParentIgnoreParens(S);
const Stmt *Parent = PM.getParentIgnoreParens(S);
if (!Parent)
return nullptr;
switch (Parent->getStmtClass()) {
case Stmt::ForStmtClass:
case Stmt::DoStmtClass:
case Stmt::WhileStmtClass:
case Stmt::ObjCForCollectionStmtClass:
case Stmt::CXXForRangeStmtClass:
return Parent;
default:
break;
}
return nullptr;
}
static PathDiagnosticLocation
getEnclosingStmtLocation(const Stmt *S, const LocationContext *LC,
bool allowNestedContexts = false) {
if (!S)
return {};
const SourceManager &SMgr = LC->getDecl()->getASTContext().getSourceManager();
while (const Stmt *Parent = getEnclosingParent(S, LC->getParentMap())) {
switch (Parent->getStmtClass()) {
case Stmt::BinaryOperatorClass: {
const auto *B = cast<BinaryOperator>(Parent);
if (B->isLogicalOp())
return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC);
break;
}
case Stmt::CompoundStmtClass:
case Stmt::StmtExprClass:
return PathDiagnosticLocation(S, SMgr, LC);
case Stmt::ChooseExprClass:
// Similar to '?' if we are referring to condition, just have the edge
// point to the entire choose expression.
if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S)
return PathDiagnosticLocation(Parent, SMgr, LC);
else
return PathDiagnosticLocation(S, SMgr, LC);
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass:
// For '?', if we are referring to condition, just have the edge point
// to the entire '?' expression.
if (allowNestedContexts ||
cast<AbstractConditionalOperator>(Parent)->getCond() == S)
return PathDiagnosticLocation(Parent, SMgr, LC);
else
return PathDiagnosticLocation(S, SMgr, LC);
case Stmt::CXXForRangeStmtClass:
if (cast<CXXForRangeStmt>(Parent)->getBody() == S)
return PathDiagnosticLocation(S, SMgr, LC);
break;
case Stmt::DoStmtClass:
return PathDiagnosticLocation(S, SMgr, LC);
case Stmt::ForStmtClass:
if (cast<ForStmt>(Parent)->getBody() == S)
return PathDiagnosticLocation(S, SMgr, LC);
break;
case Stmt::IfStmtClass:
if (cast<IfStmt>(Parent)->getCond() != S)
return PathDiagnosticLocation(S, SMgr, LC);
break;
case Stmt::ObjCForCollectionStmtClass:
if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
return PathDiagnosticLocation(S, SMgr, LC);
break;
case Stmt::WhileStmtClass:
if (cast<WhileStmt>(Parent)->getCond() != S)
return PathDiagnosticLocation(S, SMgr, LC);
break;
default:
break;
}
S = Parent;
}
assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
return PathDiagnosticLocation(S, SMgr, LC);
}
//===----------------------------------------------------------------------===//
// "Minimal" path diagnostic generation algorithm.
//===----------------------------------------------------------------------===//
/// If the piece contains a special message, add it to all the call pieces on
/// the active stack. For example, my_malloc allocated memory, so MallocChecker
/// will construct an event at the call to malloc(), and add a stack hint that
/// an allocated memory was returned. We'll use this hint to construct a message
/// when returning from the call to my_malloc
///
/// void *my_malloc() { return malloc(sizeof(int)); }
/// void fishy() {
/// void *ptr = my_malloc(); // returned allocated memory
/// } // leak
void PathDiagnosticBuilder::updateStackPiecesWithMessage(
PathDiagnosticPieceRef P, const CallWithEntryStack &CallStack) const {
if (R->hasCallStackHint(P))
for (const auto &I : CallStack) {
PathDiagnosticCallPiece *CP = I.first;
const ExplodedNode *N = I.second;
std::string stackMsg = R->getCallStackMessage(P, N);
// The last message on the path to final bug is the most important
// one. Since we traverse the path backwards, do not add the message
// if one has been previously added.
if (!CP->hasCallStackMessage())
CP->setCallStackMessage(stackMsg);
}
}
static void CompactMacroExpandedPieces(PathPieces &path,
const SourceManager& SM);
PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForSwitchOP(
const PathDiagnosticConstruct &C, const CFGBlock *Dst,
PathDiagnosticLocation &Start) const {
const SourceManager &SM = getSourceManager();
// Figure out what case arm we took.
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
PathDiagnosticLocation End;
if (const Stmt *S = Dst->getLabel()) {
End = PathDiagnosticLocation(S, SM, C.getCurrLocationContext());
switch (S->getStmtClass()) {
default:
os << "No cases match in the switch statement. "
"Control jumps to line "
<< End.asLocation().getExpansionLineNumber();
break;
case Stmt::DefaultStmtClass:
os << "Control jumps to the 'default' case at line "
<< End.asLocation().getExpansionLineNumber();
break;
case Stmt::CaseStmtClass: {
os << "Control jumps to 'case ";
const auto *Case = cast<CaseStmt>(S);
const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
// Determine if it is an enum.
bool GetRawInt = true;
if (const auto *DR = dyn_cast<DeclRefExpr>(LHS)) {
// FIXME: Maybe this should be an assertion. Are there cases
// were it is not an EnumConstantDecl?
const auto *D = dyn_cast<EnumConstantDecl>(DR->getDecl());
if (D) {
GetRawInt = false;
os << *D;
}
}
if (GetRawInt)
os << LHS->EvaluateKnownConstInt(getASTContext());
os << ":' at line " << End.asLocation().getExpansionLineNumber();
break;
}
}
} else {
os << "'Default' branch taken. ";
End = ExecutionContinues(os, C);
}
return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str());
}
PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForGotoOP(
const PathDiagnosticConstruct &C, const Stmt *S,
PathDiagnosticLocation &Start) const {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
const PathDiagnosticLocation &End =
getEnclosingStmtLocation(S, C.getCurrLocationContext());
os << "Control jumps to line " << End.asLocation().getExpansionLineNumber();
return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str());
}
PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForBinaryOP(
const PathDiagnosticConstruct &C, const Stmt *T, const CFGBlock *Src,
const CFGBlock *Dst) const {
const SourceManager &SM = getSourceManager();
const auto *B = cast<BinaryOperator>(T);
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Left side of '";
PathDiagnosticLocation Start, End;
if (B->getOpcode() == BO_LAnd) {
os << "&&"
<< "' is ";
if (*(Src->succ_begin() + 1) == Dst) {
os << "false";
End = PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
Start =
PathDiagnosticLocation::createOperatorLoc(B, SM);
} else {
os << "true";
Start =
PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
End = ExecutionContinues(C);
}
} else {
assert(B->getOpcode() == BO_LOr);
os << "||"
<< "' is ";
if (*(Src->succ_begin() + 1) == Dst) {
os << "false";
Start =
PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
End = ExecutionContinues(C);
} else {
os << "true";
End = PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
Start =
PathDiagnosticLocation::createOperatorLoc(B, SM);
}
}
return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str());
}
void PathDiagnosticBuilder::generateMinimalDiagForBlockEdge(
PathDiagnosticConstruct &C, BlockEdge BE) const {
const SourceManager &SM = getSourceManager();
const LocationContext *LC = C.getCurrLocationContext();
const CFGBlock *Src = BE.getSrc();
const CFGBlock *Dst = BE.getDst();
const Stmt *T = Src->getTerminatorStmt();
if (!T)
return;
auto Start = PathDiagnosticLocation::createBegin(T, SM, LC);
switch (T->getStmtClass()) {
default:
break;
case Stmt::GotoStmtClass:
case Stmt::IndirectGotoStmtClass: {
if (const Stmt *S = C.getCurrentNode()->getNextStmtForDiagnostics())
C.getActivePath().push_front(generateDiagForGotoOP(C, S, Start));
break;
}
case Stmt::SwitchStmtClass: {
C.getActivePath().push_front(generateDiagForSwitchOP(C, Dst, Start));
break;
}
case Stmt::BreakStmtClass:
case Stmt::ContinueStmtClass: {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
PathDiagnosticLocation End = ExecutionContinues(os, C);
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
break;
}
// Determine control-flow for ternary '?'.
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass: {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "'?' condition is ";
if (*(Src->succ_begin() + 1) == Dst)
os << "false";
else
os << "true";
PathDiagnosticLocation End = ExecutionContinues(C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
break;
}
// Determine control-flow for short-circuited '&&' and '||'.
case Stmt::BinaryOperatorClass: {
if (!C.supportsLogicalOpControlFlow())
break;
C.getActivePath().push_front(generateDiagForBinaryOP(C, T, Src, Dst));
break;
}
case Stmt::DoStmtClass:
if (*(Src->succ_begin()) == Dst) {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Loop condition is true. ";
PathDiagnosticLocation End = ExecutionContinues(os, C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
} else {
PathDiagnosticLocation End = ExecutionContinues(C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Loop condition is false. Exiting loop"));
}
break;
case Stmt::WhileStmtClass:
case Stmt::ForStmtClass:
if (*(Src->succ_begin() + 1) == Dst) {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Loop condition is false. ";
PathDiagnosticLocation End = ExecutionContinues(os, C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
} else {
PathDiagnosticLocation End = ExecutionContinues(C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Loop condition is true. Entering loop body"));
}
break;
case Stmt::IfStmtClass: {
PathDiagnosticLocation End = ExecutionContinues(C);
if (const Stmt *S = End.asStmt())
End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
if (*(Src->succ_begin() + 1) == Dst)
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Taking false branch"));
else
C.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Taking true branch"));
break;
}
}
}
//===----------------------------------------------------------------------===//
// Functions for determining if a loop was executed 0 times.
//===----------------------------------------------------------------------===//
static bool isLoop(const Stmt *Term) {
switch (Term->getStmtClass()) {
case Stmt::ForStmtClass:
case Stmt::WhileStmtClass:
case Stmt::ObjCForCollectionStmtClass:
case Stmt::CXXForRangeStmtClass:
return true;
default:
// Note that we intentionally do not include do..while here.
return false;
}
}
static bool isJumpToFalseBranch(const BlockEdge *BE) {
const CFGBlock *Src = BE->getSrc();
assert(Src->succ_size() == 2);
return (*(Src->succ_begin()+1) == BE->getDst());
}
static bool isContainedByStmt(const ParentMap &PM, const Stmt *S,
const Stmt *SubS) {
while (SubS) {
if (SubS == S)
return true;
SubS = PM.getParent(SubS);
}
return false;
}
static const Stmt *getStmtBeforeCond(const ParentMap &PM, const Stmt *Term,
const ExplodedNode *N) {
while (N) {
Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>();
if (SP) {
const Stmt *S = SP->getStmt();
if (!isContainedByStmt(PM, Term, S))
return S;
}
N = N->getFirstPred();
}
return nullptr;
}
static bool isInLoopBody(const ParentMap &PM, const Stmt *S, const Stmt *Term) {
const Stmt *LoopBody = nullptr;
switch (Term->getStmtClass()) {
case Stmt::CXXForRangeStmtClass: {
const auto *FR = cast<CXXForRangeStmt>(Term);
if (isContainedByStmt(PM, FR->getInc(), S))
return true;
if (isContainedByStmt(PM, FR->getLoopVarStmt(), S))
return true;
LoopBody = FR->getBody();
break;
}
case Stmt::ForStmtClass: {
const auto *FS = cast<ForStmt>(Term);
if (isContainedByStmt(PM, FS->getInc(), S))
return true;
LoopBody = FS->getBody();
break;
}
case Stmt::ObjCForCollectionStmtClass: {
const auto *FC = cast<ObjCForCollectionStmt>(Term);
LoopBody = FC->getBody();
break;
}
case Stmt::WhileStmtClass:
LoopBody = cast<WhileStmt>(Term)->getBody();
break;
default:
return false;
}
return isContainedByStmt(PM, LoopBody, S);
}
/// Adds a sanitized control-flow diagnostic edge to a path.
static void addEdgeToPath(PathPieces &path,
PathDiagnosticLocation &PrevLoc,
PathDiagnosticLocation NewLoc) {
if (!NewLoc.isValid())
return;
SourceLocation NewLocL = NewLoc.asLocation();
if (NewLocL.isInvalid())
return;
if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) {
PrevLoc = NewLoc;
return;
}
// Ignore self-edges, which occur when there are multiple nodes at the same
// statement.
if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt())
return;
path.push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(NewLoc, PrevLoc));
PrevLoc = NewLoc;
}
/// A customized wrapper for CFGBlock::getTerminatorCondition()
/// which returns the element for ObjCForCollectionStmts.
static const Stmt *getTerminatorCondition(const CFGBlock *B) {
const Stmt *S = B->getTerminatorCondition();
if (const auto *FS = dyn_cast_or_null<ObjCForCollectionStmt>(S))
return FS->getElement();
return S;
}
constexpr llvm::StringLiteral StrEnteringLoop = "Entering loop body";
constexpr llvm::StringLiteral StrLoopBodyZero = "Loop body executed 0 times";
constexpr llvm::StringLiteral StrLoopRangeEmpty =
"Loop body skipped when range is empty";
constexpr llvm::StringLiteral StrLoopCollectionEmpty =
"Loop body skipped when collection is empty";
static std::unique_ptr<FilesToLineNumsMap>
findExecutedLines(const SourceManager &SM, const ExplodedNode *N);
void PathDiagnosticBuilder::generatePathDiagnosticsForNode(
PathDiagnosticConstruct &C, PathDiagnosticLocation &PrevLoc) const {
ProgramPoint P = C.getCurrentNode()->getLocation();
const SourceManager &SM = getSourceManager();
// Have we encountered an entrance to a call? It may be
// the case that we have not encountered a matching
// call exit before this point. This means that the path
// terminated within the call itself.
if (auto CE = P.getAs<CallEnter>()) {
if (C.shouldAddPathEdges()) {
// Add an edge to the start of the function.
const StackFrameContext *CalleeLC = CE->getCalleeContext();
const Decl *D = CalleeLC->getDecl();
// Add the edge only when the callee has body. We jump to the beginning
// of the *declaration*, however we expect it to be followed by the
// body. This isn't the case for autosynthesized property accessors in
// Objective-C. No need for a similar extra check for CallExit points
// because the exit edge comes from a statement (i.e. return),
// not from declaration.
if (D->hasBody())
addEdgeToPath(C.getActivePath(), PrevLoc,
PathDiagnosticLocation::createBegin(D, SM));
}
// Did we visit an entire call?
bool VisitedEntireCall = C.PD->isWithinCall();
C.PD->popActivePath();
PathDiagnosticCallPiece *Call;
if (VisitedEntireCall) {
Call = cast<PathDiagnosticCallPiece>(C.getActivePath().front().get());
} else {
// The path terminated within a nested location context, create a new
// call piece to encapsulate the rest of the path pieces.
const Decl *Caller = CE->getLocationContext()->getDecl();
Call = PathDiagnosticCallPiece::construct(C.getActivePath(), Caller);
assert(C.getActivePath().size() == 1 &&
C.getActivePath().front().get() == Call);
// Since we just transferred the path over to the call piece, reset the
// mapping of the active path to the current location context.
assert(C.isInLocCtxMap(&C.getActivePath()) &&
"When we ascend to a previously unvisited call, the active path's "
"address shouldn't change, but rather should be compacted into "
"a single CallEvent!");
C.updateLocCtxMap(&C.getActivePath(), C.getCurrLocationContext());
// Record the location context mapping for the path within the call.
assert(!C.isInLocCtxMap(&Call->path) &&
"When we ascend to a previously unvisited call, this must be the "
"first time we encounter the caller context!");
C.updateLocCtxMap(&Call->path, CE->getCalleeContext());
}
Call->setCallee(*CE, SM);
// Update the previous location in the active path.
PrevLoc = Call->getLocation();
if (!C.CallStack.empty()) {
assert(C.CallStack.back().first == Call);
C.CallStack.pop_back();
}
return;
}
assert(C.getCurrLocationContext() == C.getLocationContextForActivePath() &&
"The current position in the bug path is out of sync with the "
"location context associated with the active path!");
// Have we encountered an exit from a function call?
if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
// We are descending into a call (backwards). Construct
// a new call piece to contain the path pieces for that call.
auto Call = PathDiagnosticCallPiece::construct(*CE, SM);
// Record the mapping from call piece to LocationContext.
assert(!C.isInLocCtxMap(&Call->path) &&
"We just entered a call, this must've been the first time we "
"encounter its context!");
C.updateLocCtxMap(&Call->path, CE->getCalleeContext());
if (C.shouldAddPathEdges()) {
// Add the edge to the return site.
addEdgeToPath(C.getActivePath(), PrevLoc, Call->callReturn);
PrevLoc.invalidate();
}
auto *P = Call.get();
C.getActivePath().push_front(std::move(Call));
// Make the contents of the call the active path for now.
C.PD->pushActivePath(&P->path);
C.CallStack.push_back(CallWithEntry(P, C.getCurrentNode()));
return;
}
if (auto PS = P.getAs<PostStmt>()) {
if (!C.shouldAddPathEdges())
return;
// Add an edge. If this is an ObjCForCollectionStmt do
// not add an edge here as it appears in the CFG both
// as a terminator and as a terminator condition.
if (!isa<ObjCForCollectionStmt>(PS->getStmt())) {
PathDiagnosticLocation L =
PathDiagnosticLocation(PS->getStmt(), SM, C.getCurrLocationContext());
addEdgeToPath(C.getActivePath(), PrevLoc, L);
}
} else if (auto BE = P.getAs<BlockEdge>()) {
if (!C.shouldAddPathEdges()) {
generateMinimalDiagForBlockEdge(C, *BE);
return;
}
// Are we jumping to the head of a loop? Add a special diagnostic.
if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
PathDiagnosticLocation L(Loop, SM, C.getCurrLocationContext());
const Stmt *Body = nullptr;
if (const auto *FS = dyn_cast<ForStmt>(Loop))
Body = FS->getBody();
else if (const auto *WS = dyn_cast<WhileStmt>(Loop))
Body = WS->getBody();
else if (const auto *OFS = dyn_cast<ObjCForCollectionStmt>(Loop)) {
Body = OFS->getBody();
} else if (const auto *FRS = dyn_cast<CXXForRangeStmt>(Loop)) {
Body = FRS->getBody();
}
// do-while statements are explicitly excluded here
auto p = std::make_shared<PathDiagnosticEventPiece>(
L, "Looping back to the head "
"of the loop");
p->setPrunable(true);
addEdgeToPath(C.getActivePath(), PrevLoc, p->getLocation());
C.getActivePath().push_front(std::move(p));
if (const auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
addEdgeToPath(C.getActivePath(), PrevLoc,
PathDiagnosticLocation::createEndBrace(CS, SM));
}
}
const CFGBlock *BSrc = BE->getSrc();
const ParentMap &PM = C.getParentMap();
if (const Stmt *Term = BSrc->getTerminatorStmt()) {
// Are we jumping past the loop body without ever executing the
// loop (because the condition was false)?
if (isLoop(Term)) {
const Stmt *TermCond = getTerminatorCondition(BSrc);
bool IsInLoopBody = isInLoopBody(
PM, getStmtBeforeCond(PM, TermCond, C.getCurrentNode()), Term);
StringRef str;
if (isJumpToFalseBranch(&*BE)) {
if (!IsInLoopBody) {
if (isa<ObjCForCollectionStmt>(Term)) {
str = StrLoopCollectionEmpty;
} else if (isa<CXXForRangeStmt>(Term)) {
str = StrLoopRangeEmpty;
} else {
str = StrLoopBodyZero;
}
}
} else {
str = StrEnteringLoop;
}
if (!str.empty()) {
PathDiagnosticLocation L(TermCond ? TermCond : Term, SM,
C.getCurrLocationContext());
auto PE = std::make_shared<PathDiagnosticEventPiece>(L, str);
PE->setPrunable(true);
addEdgeToPath(C.getActivePath(), PrevLoc, PE->getLocation());
C.getActivePath().push_front(std::move(PE));
}
} else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) ||
isa<GotoStmt>(Term)) {
PathDiagnosticLocation L(Term, SM, C.getCurrLocationContext());
addEdgeToPath(C.getActivePath(), PrevLoc, L);
}
}
}
}
static std::unique_ptr<PathDiagnostic>
generateDiagnosticForBasicReport(const BasicBugReport *R) {
const BugType &BT = R->getBugType();
return std::make_unique<PathDiagnostic>(
BT.getCheckerName(), R->getDeclWithIssue(), BT.getDescription(),
R->getDescription(), R->getShortDescription(/*UseFallback=*/false),
BT.getCategory(), R->getUniqueingLocation(), R->getUniqueingDecl(),
std::make_unique<FilesToLineNumsMap>());
}
static std::unique_ptr<PathDiagnostic>
generateEmptyDiagnosticForReport(const PathSensitiveBugReport *R,
const SourceManager &SM) {
const BugType &BT = R->getBugType();
return std::make_unique<PathDiagnostic>(
BT.getCheckerName(), R->getDeclWithIssue(), BT.getDescription(),
R->getDescription(), R->getShortDescription(/*UseFallback=*/false),
BT.getCategory(), R->getUniqueingLocation(), R->getUniqueingDecl(),
findExecutedLines(SM, R->getErrorNode()));
}
static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) {
if (!S)
return nullptr;
while (true) {
S = PM.getParentIgnoreParens(S);
if (!S)
break;
if (isa<FullExpr>(S) ||
isa<CXXBindTemporaryExpr>(S) ||
isa<SubstNonTypeTemplateParmExpr>(S))
continue;
break;
}
return S;
}
static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) {
switch (S->getStmtClass()) {
case Stmt::BinaryOperatorClass: {
const auto *BO = cast<BinaryOperator>(S);
if (!BO->isLogicalOp())
return false;
return BO->getLHS() == Cond || BO->getRHS() == Cond;
}
case Stmt::IfStmtClass:
return cast<IfStmt>(S)->getCond() == Cond;
case Stmt::ForStmtClass:
return cast<ForStmt>(S)->getCond() == Cond;
case Stmt::WhileStmtClass:
return cast<WhileStmt>(S)->getCond() == Cond;
case Stmt::DoStmtClass:
return cast<DoStmt>(S)->getCond() == Cond;
case Stmt::ChooseExprClass:
return cast<ChooseExpr>(S)->getCond() == Cond;
case Stmt::IndirectGotoStmtClass:
return cast<IndirectGotoStmt>(S)->getTarget() == Cond;
case Stmt::SwitchStmtClass:
return cast<SwitchStmt>(S)->getCond() == Cond;
case Stmt::BinaryConditionalOperatorClass:
return cast<BinaryConditionalOperator>(S)->getCond() == Cond;
case Stmt::ConditionalOperatorClass: {
const auto *CO = cast<ConditionalOperator>(S);
return CO->getCond() == Cond ||
CO->getLHS() == Cond ||
CO->getRHS() == Cond;
}
case Stmt::ObjCForCollectionStmtClass:
return cast<ObjCForCollectionStmt>(S)->getElement() == Cond;
case Stmt::CXXForRangeStmtClass: {
const auto *FRS = cast<CXXForRangeStmt>(S);
return FRS->getCond() == Cond || FRS->getRangeInit() == Cond;
}
default:
return false;
}
}
static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) {
if (const auto *FS = dyn_cast<ForStmt>(FL))
return FS->getInc() == S || FS->getInit() == S;
if (const auto *FRS = dyn_cast<CXXForRangeStmt>(FL))
return FRS->getInc() == S || FRS->getRangeStmt() == S ||
FRS->getLoopVarStmt() || FRS->getRangeInit() == S;
return false;
}
using OptimizedCallsSet = llvm::DenseSet<const PathDiagnosticCallPiece *>;
/// Adds synthetic edges from top-level statements to their subexpressions.
///
/// This avoids a "swoosh" effect, where an edge from a top-level statement A
/// points to a sub-expression B.1 that's not at the start of B. In these cases,
/// we'd like to see an edge from A to B, then another one from B to B.1.
static void addContextEdges(PathPieces &pieces, const LocationContext *LC) {
const ParentMap &PM = LC->getParentMap();
PathPieces::iterator Prev = pieces.end();
for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E;
Prev = I, ++I) {
auto *Piece = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!Piece)
continue;
PathDiagnosticLocation SrcLoc = Piece->getStartLocation();
SmallVector<PathDiagnosticLocation, 4> SrcContexts;
PathDiagnosticLocation NextSrcContext = SrcLoc;
const Stmt *InnerStmt = nullptr;
while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) {
SrcContexts.push_back(NextSrcContext);
InnerStmt = NextSrcContext.asStmt();
NextSrcContext = getEnclosingStmtLocation(InnerStmt, LC,
/*allowNested=*/true);
}
// Repeatedly split the edge as necessary.
// This is important for nested logical expressions (||, &&, ?:) where we
// want to show all the levels of context.
while (true) {
const Stmt *Dst = Piece->getEndLocation().getStmtOrNull();
// We are looking at an edge. Is the destination within a larger
// expression?
PathDiagnosticLocation DstContext =
getEnclosingStmtLocation(Dst, LC, /*allowNested=*/true);
if (!DstContext.isValid() || DstContext.asStmt() == Dst)
break;
// If the source is in the same context, we're already good.
if (llvm::find(SrcContexts, DstContext) != SrcContexts.end())
break;
// Update the subexpression node to point to the context edge.
Piece->setStartLocation(DstContext);
// Try to extend the previous edge if it's at the same level as the source
// context.
if (Prev != E) {
auto *PrevPiece = dyn_cast<PathDiagnosticControlFlowPiece>(Prev->get());
if (PrevPiece) {
if (const Stmt *PrevSrc =
PrevPiece->getStartLocation().getStmtOrNull()) {
const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM);
if (PrevSrcParent ==
getStmtParent(DstContext.getStmtOrNull(), PM)) {
PrevPiece->setEndLocation(DstContext);
break;
}
}
}
}
// Otherwise, split the current edge into a context edge and a
// subexpression edge. Note that the context statement may itself have
// context.
auto P =
std::make_shared<PathDiagnosticControlFlowPiece>(SrcLoc, DstContext);
Piece = P.get();
I = pieces.insert(I, std::move(P));
}
}
}
/// Move edges from a branch condition to a branch target
/// when the condition is simple.
///
/// This restructures some of the work of addContextEdges. That function
/// creates edges this may destroy, but they work together to create a more
/// aesthetically set of edges around branches. After the call to
/// addContextEdges, we may have (1) an edge to the branch, (2) an edge from
/// the branch to the branch condition, and (3) an edge from the branch
/// condition to the branch target. We keep (1), but may wish to remove (2)
/// and move the source of (3) to the branch if the branch condition is simple.
static void simplifySimpleBranches(PathPieces &pieces) {
for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) {
const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI)
continue;
const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
if (!s1Start || !s1End)
continue;
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
PathDiagnosticControlFlowPiece *PieceNextI = nullptr;
while (true) {
if (NextI == E)
break;
const auto *EV = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
if (EV) {
StringRef S = EV->getString();
if (S == StrEnteringLoop || S == StrLoopBodyZero ||
S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) {
++NextI;
continue;
}
break;
}
PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
break;
}
if (!PieceNextI)
continue;
const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
if (!s2Start || !s2End || s1End != s2Start)
continue;
// We only perform this transformation for specific branch kinds.
// We don't want to do this for do..while, for example.
if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) ||
isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) ||
isa<CXXForRangeStmt>(s1Start)))
continue;
// Is s1End the branch condition?
if (!isConditionForTerminator(s1Start, s1End))
continue;
// Perform the hoisting by eliminating (2) and changing the start
// location of (3).
PieceNextI->setStartLocation(PieceI->getStartLocation());
I = pieces.erase(I);
}
}
/// Returns the number of bytes in the given (character-based) SourceRange.
///
/// If the locations in the range are not on the same line, returns None.
///
/// Note that this does not do a precise user-visible character or column count.
static Optional<size_t> getLengthOnSingleLine(const SourceManager &SM,
SourceRange Range) {
SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()),
SM.getExpansionRange(Range.getEnd()).getEnd());
FileID FID = SM.getFileID(ExpansionRange.getBegin());
if (FID != SM.getFileID(ExpansionRange.getEnd()))
return None;
bool Invalid;
const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid);
if (Invalid)
return None;
unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin());
unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd());
StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset);
// We're searching the raw bytes of the buffer here, which might include
// escaped newlines and such. That's okay; we're trying to decide whether the
// SourceRange is covering a large or small amount of space in the user's
// editor.
if (Snippet.find_first_of("\r\n") != StringRef::npos)
return None;
// This isn't Unicode-aware, but it doesn't need to be.
return Snippet.size();
}
/// \sa getLengthOnSingleLine(SourceManager, SourceRange)
static Optional<size_t> getLengthOnSingleLine(const SourceManager &SM,
const Stmt *S) {
return getLengthOnSingleLine(SM, S->getSourceRange());
}
/// Eliminate two-edge cycles created by addContextEdges().
///
/// Once all the context edges are in place, there are plenty of cases where
/// there's a single edge from a top-level statement to a subexpression,
/// followed by a single path note, and then a reverse edge to get back out to
/// the top level. If the statement is simple enough, the subexpression edges
/// just add noise and make it harder to understand what's going on.
///
/// This function only removes edges in pairs, because removing only one edge
/// might leave other edges dangling.
///
/// This will not remove edges in more complicated situations:
/// - if there is more than one "hop" leading to or from a subexpression.
/// - if there is an inlined call between the edges instead of a single event.
/// - if the whole statement is large enough that having subexpression arrows
/// might be helpful.
static void removeContextCycles(PathPieces &Path, const SourceManager &SM) {
for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) {
// Pattern match the current piece and its successor.
const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI) {
++I;
continue;
}
const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
const auto *PieceNextI =
dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
if (!PieceNextI) {
if (isa<PathDiagnosticEventPiece>(NextI->get())) {
++NextI;
if (NextI == E)
break;
PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
}
if (!PieceNextI) {
++I;
continue;
}
}
const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) {
const size_t MAX_SHORT_LINE_LENGTH = 80;
Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start);
if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) {
Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start);
if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) {
Path.erase(I);
I = Path.erase(NextI);
continue;
}
}
}
++I;
}
}
/// Return true if X is contained by Y.
static bool lexicalContains(const ParentMap &PM, const Stmt *X, const Stmt *Y) {
while (X) {
if (X == Y)
return true;
X = PM.getParent(X);
}
return false;
}
// Remove short edges on the same line less than 3 columns in difference.
static void removePunyEdges(PathPieces &path, const SourceManager &SM,
const ParentMap &PM) {
bool erased = false;
for (PathPieces::iterator I = path.begin(), E = path.end(); I != E;
erased ? I : ++I) {
erased = false;
const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI)
continue;
const Stmt *start = PieceI->getStartLocation().getStmtOrNull();
const Stmt *end = PieceI->getEndLocation().getStmtOrNull();
if (!start || !end)
continue;
const Stmt *endParent = PM.getParent(end);
if (!endParent)
continue;
if (isConditionForTerminator(end, endParent))
continue;
SourceLocation FirstLoc = start->getBeginLoc();
SourceLocation SecondLoc = end->getBeginLoc();
if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc))
continue;
if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc))
std::swap(SecondLoc, FirstLoc);
SourceRange EdgeRange(FirstLoc, SecondLoc);
Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange);
// If the statements are on different lines, continue.
if (!ByteWidth)
continue;
const size_t MAX_PUNY_EDGE_LENGTH = 2;
if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) {
// FIXME: There are enough /bytes/ between the endpoints of the edge, but
// there might not be enough /columns/. A proper user-visible column count
// is probably too expensive, though.
I = path.erase(I);
erased = true;
continue;
}
}
}
static void removeIdenticalEvents(PathPieces &path) {
for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) {
const auto *PieceI = dyn_cast<PathDiagnosticEventPiece>(I->get());
if (!PieceI)
continue;
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
return;
const auto *PieceNextI = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
if (!PieceNextI)
continue;
// Erase the second piece if it has the same exact message text.
if (PieceI->getString() == PieceNextI->getString()) {
path.erase(NextI);
}
}
}
static bool optimizeEdges(const PathDiagnosticConstruct &C, PathPieces &path,
OptimizedCallsSet &OCS) {
bool hasChanges = false;
const LocationContext *LC = C.getLocationContextFor(&path);
assert(LC);
const ParentMap &PM = LC->getParentMap();
const SourceManager &SM = C.getSourceManager();
for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) {
// Optimize subpaths.
if (auto *CallI = dyn_cast<PathDiagnosticCallPiece>(I->get())) {
// Record the fact that a call has been optimized so we only do the
// effort once.
if (!OCS.count(CallI)) {
while (optimizeEdges(C, CallI->path, OCS)) {
}
OCS.insert(CallI);
}
++I;
continue;
}
// Pattern match the current piece and its successor.
auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI) {
++I;
continue;
}
const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
const Stmt *level1 = getStmtParent(s1Start, PM);
const Stmt *level2 = getStmtParent(s1End, PM);
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
const auto *PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
if (!PieceNextI) {
++I;
continue;
}
const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
const Stmt *level3 = getStmtParent(s2Start, PM);
const Stmt *level4 = getStmtParent(s2End, PM);
// Rule I.
//
// If we have two consecutive control edges whose end/begin locations
// are at the same level (e.g. statements or top-level expressions within
// a compound statement, or siblings share a single ancestor expression),
// then merge them if they have no interesting intermediate event.
//
// For example:
//
// (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common
// parent is '1'. Here 'x.y.z' represents the hierarchy of statements.
//
// NOTE: this will be limited later in cases where we add barriers
// to prevent this optimization.
if (level1 && level1 == level2 && level1 == level3 && level1 == level4) {
PieceI->setEndLocation(PieceNextI->getEndLocation());
path.erase(NextI);
hasChanges = true;
continue;
}
// Rule II.
//
// Eliminate edges between subexpressions and parent expressions
// when the subexpression is consumed.
//
// NOTE: this will be limited later in cases where we add barriers
// to prevent this optimization.
if (s1End && s1End == s2Start && level2) {
bool removeEdge = false;
// Remove edges into the increment or initialization of a
// loop that have no interleaving event. This means that
// they aren't interesting.
if (isIncrementOrInitInForLoop(s1End, level2))
removeEdge = true;
// Next only consider edges that are not anchored on
// the condition of a terminator. This are intermediate edges
// that we might want to trim.
else if (!isConditionForTerminator(level2, s1End)) {
// Trim edges on expressions that are consumed by
// the parent expression.
if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) {
removeEdge = true;
}
// Trim edges where a lexical containment doesn't exist.
// For example:
//
// X -> Y -> Z
//
// If 'Z' lexically contains Y (it is an ancestor) and
// 'X' does not lexically contain Y (it is a descendant OR
// it has no lexical relationship at all) then trim.
//
// This can eliminate edges where we dive into a subexpression
// and then pop back out, etc.
else if (s1Start && s2End &&
lexicalContains(PM, s2Start, s2End) &&
!lexicalContains(PM, s1End, s1Start)) {
removeEdge = true;
}
// Trim edges from a subexpression back to the top level if the
// subexpression is on a different line.
//
// A.1 -> A -> B
// becomes
// A.1 -> B
//
// These edges just look ugly and don't usually add anything.
else if (s1Start && s2End &&
lexicalContains(PM, s1Start, s1End)) {
SourceRange EdgeRange(PieceI->getEndLocation().asLocation(),
PieceI->getStartLocation().asLocation());
if (!getLengthOnSingleLine(SM, EdgeRange).hasValue())
removeEdge = true;
}
}
if (removeEdge) {
PieceI->setEndLocation(PieceNextI->getEndLocation());
path.erase(NextI);
hasChanges = true;
continue;
}
}
// Optimize edges for ObjC fast-enumeration loops.
//
// (X -> collection) -> (collection -> element)
//
// becomes:
//
// (X -> element)
if (s1End == s2Start) {
const auto *FS = dyn_cast_or_null<ObjCForCollectionStmt>(level3);
if (FS && FS->getCollection()->IgnoreParens() == s2Start &&
s2End == FS->getElement()) {
PieceI->setEndLocation(PieceNextI->getEndLocation());
path.erase(NextI);
hasChanges = true;
continue;
}
}
// No changes at this index? Move to the next one.
++I;
}
if (!hasChanges) {
// Adjust edges into subexpressions to make them more uniform
// and aesthetically pleasing.
addContextEdges(path, LC);
// Remove "cyclical" edges that include one or more context edges.
removeContextCycles(path, SM);
// Hoist edges originating from branch conditions to branches
// for simple branches.
simplifySimpleBranches(path);
// Remove any puny edges left over after primary optimization pass.
removePunyEdges(path, SM, PM);
// Remove identical events.
removeIdenticalEvents(path);
}
return hasChanges;
}
/// Drop the very first edge in a path, which should be a function entry edge.
///
/// If the first edge is not a function entry edge (say, because the first
/// statement had an invalid source location), this function does nothing.
// FIXME: We should just generate invalid edges anyway and have the optimizer
// deal with them.
static void dropFunctionEntryEdge(const PathDiagnosticConstruct &C,
PathPieces &Path) {
const auto *FirstEdge =
dyn_cast<PathDiagnosticControlFlowPiece>(Path.front().get());
if (!FirstEdge)
return;
const Decl *D = C.getLocationContextFor(&Path)->getDecl();
PathDiagnosticLocation EntryLoc =
PathDiagnosticLocation::createBegin(D, C.getSourceManager());
if (FirstEdge->getStartLocation() != EntryLoc)
return;
Path.pop_front();
}
/// Populate executes lines with lines containing at least one diagnostics.
static void updateExecutedLinesWithDiagnosticPieces(PathDiagnostic &PD) {
PathPieces path = PD.path.flatten(/*ShouldFlattenMacros=*/true);
FilesToLineNumsMap &ExecutedLines = PD.getExecutedLines();
for (const auto &P : path) {
FullSourceLoc Loc = P->getLocation().asLocation().getExpansionLoc();
FileID FID = Loc.getFileID();
unsigned LineNo = Loc.getLineNumber();
assert(FID.isValid());
ExecutedLines[FID].insert(LineNo);
}
}
PathDiagnosticConstruct::PathDiagnosticConstruct(
const PathDiagnosticConsumer *PDC, const ExplodedNode *ErrorNode,
const PathSensitiveBugReport *R)
: Consumer(PDC), CurrentNode(ErrorNode),
SM(CurrentNode->getCodeDecl().getASTContext().getSourceManager()),
PD(generateEmptyDiagnosticForReport(R, getSourceManager())) {
LCM[&PD->getActivePath()] = ErrorNode->getLocationContext();
}
PathDiagnosticBuilder::PathDiagnosticBuilder(
BugReporterContext BRC, std::unique_ptr<ExplodedGraph> BugPath,
PathSensitiveBugReport *r, const ExplodedNode *ErrorNode,
std::unique_ptr<VisitorsDiagnosticsTy> VisitorsDiagnostics)
: BugReporterContext(BRC), BugPath(std::move(BugPath)), R(r),
ErrorNode(ErrorNode),
VisitorsDiagnostics(std::move(VisitorsDiagnostics)) {}
std::unique_ptr<PathDiagnostic>
PathDiagnosticBuilder::generate(const PathDiagnosticConsumer *PDC) const {
PathDiagnosticConstruct Construct(PDC, ErrorNode, R);
const SourceManager &SM = getSourceManager();
const AnalyzerOptions &Opts = getAnalyzerOptions();
StringRef ErrorTag = ErrorNode->getLocation().getTag()->getTagDescription();
// See whether we need to silence the checker/package.
// FIXME: This will not work if the report was emitted with an incorrect tag.
for (const std::string &CheckerOrPackage : Opts.SilencedCheckersAndPackages) {
if (ErrorTag.startswith(CheckerOrPackage))
return nullptr;
}
if (!PDC->shouldGenerateDiagnostics())
return generateEmptyDiagnosticForReport(R, getSourceManager());
// Construct the final (warning) event for the bug report.
auto EndNotes = VisitorsDiagnostics->find(ErrorNode);
PathDiagnosticPieceRef LastPiece;
if (EndNotes != VisitorsDiagnostics->end()) {
assert(!EndNotes->second.empty());
LastPiece = EndNotes->second[0];
} else {
LastPiece = BugReporterVisitor::getDefaultEndPath(*this, ErrorNode,
*getBugReport());
}
Construct.PD->setEndOfPath(LastPiece);
PathDiagnosticLocation PrevLoc = Construct.PD->getLocation();
// From the error node to the root, ascend the bug path and construct the bug
// report.
while (Construct.ascendToPrevNode()) {
generatePathDiagnosticsForNode(Construct, PrevLoc);
auto VisitorNotes = VisitorsDiagnostics->find(Construct.getCurrentNode());
if (VisitorNotes == VisitorsDiagnostics->end())
continue;
// This is a workaround due to inability to put shared PathDiagnosticPiece
// into a FoldingSet.
std::set<llvm::FoldingSetNodeID> DeduplicationSet;
// Add pieces from custom visitors.
for (const PathDiagnosticPieceRef &Note : VisitorNotes->second) {
llvm::FoldingSetNodeID ID;
Note->Profile(ID);
if (!DeduplicationSet.insert(ID).second)
continue;
if (PDC->shouldAddPathEdges())
addEdgeToPath(Construct.getActivePath(), PrevLoc, Note->getLocation());
updateStackPiecesWithMessage(Note, Construct.CallStack);
Construct.getActivePath().push_front(Note);
}
}
if (PDC->shouldAddPathEdges()) {
// Add an edge to the start of the function.
// We'll prune it out later, but it helps make diagnostics more uniform.
const StackFrameContext *CalleeLC =
Construct.getLocationContextForActivePath()->getStackFrame();
const Decl *D = CalleeLC->getDecl();
addEdgeToPath(Construct.getActivePath(), PrevLoc,
PathDiagnosticLocation::createBegin(D, SM));
}
// Finally, prune the diagnostic path of uninteresting stuff.
if (!Construct.PD->path.empty()) {
if (R->shouldPrunePath() && Opts.ShouldPrunePaths) {
bool stillHasNotes =
removeUnneededCalls(Construct, Construct.getMutablePieces(), R);
assert(stillHasNotes);
(void)stillHasNotes;
}
// Remove pop-up notes if needed.
if (!Opts.ShouldAddPopUpNotes)
removePopUpNotes(Construct.getMutablePieces());
// Redirect all call pieces to have valid locations.
adjustCallLocations(Construct.getMutablePieces());
removePiecesWithInvalidLocations(Construct.getMutablePieces());
if (PDC->shouldAddPathEdges()) {
// Reduce the number of edges from a very conservative set
// to an aesthetically pleasing subset that conveys the
// necessary information.
OptimizedCallsSet OCS;
while (optimizeEdges(Construct, Construct.getMutablePieces(), OCS)) {
}
// Drop the very first function-entry edge. It's not really necessary
// for top-level functions.
dropFunctionEntryEdge(Construct, Construct.getMutablePieces());
}
// Remove messages that are basically the same, and edges that may not
// make sense.
// We have to do this after edge optimization in the Extensive mode.
removeRedundantMsgs(Construct.getMutablePieces());
removeEdgesToDefaultInitializers(Construct.getMutablePieces());
}
if (Opts.ShouldDisplayMacroExpansions)
CompactMacroExpandedPieces(Construct.getMutablePieces(), SM);
return std::move(Construct.PD);
}
//===----------------------------------------------------------------------===//
// Methods for BugType and subclasses.
//===----------------------------------------------------------------------===//
void BugType::anchor() {}
void BuiltinBug::anchor() {}
//===----------------------------------------------------------------------===//
// Methods for BugReport and subclasses.
//===----------------------------------------------------------------------===//
void PathSensitiveBugReport::addVisitor(
std::unique_ptr<BugReporterVisitor> visitor) {
if (!visitor)
return;
llvm::FoldingSetNodeID ID;
visitor->Profile(ID);
void *InsertPos = nullptr;
if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) {
return;
}
Callbacks.push_back(std::move(visitor));
}
void PathSensitiveBugReport::clearVisitors() {
Callbacks.clear();
}
const Decl *PathSensitiveBugReport::getDeclWithIssue() const {
const ExplodedNode *N = getErrorNode();
if (!N)
return nullptr;
const LocationContext *LC = N->getLocationContext();
return LC->getStackFrame()->getDecl();
}
void BasicBugReport::Profile(llvm::FoldingSetNodeID& hash) const {
hash.AddInteger(static_cast<int>(getKind()));
hash.AddPointer(&BT);
hash.AddString(Description);
assert(Location.isValid());
Location.Profile(hash);
for (SourceRange range : Ranges) {
if (!range.isValid())
continue;
hash.AddInteger(range.getBegin().getRawEncoding());
hash.AddInteger(range.getEnd().getRawEncoding());
}
}
void PathSensitiveBugReport::Profile(llvm::FoldingSetNodeID &hash) const {
hash.AddInteger(static_cast<int>(getKind()));
hash.AddPointer(&BT);
hash.AddString(Description);
PathDiagnosticLocation UL = getUniqueingLocation();
if (UL.isValid()) {
UL.Profile(hash);
} else {
// TODO: The statement may be null if the report was emitted before any
// statements were executed. In particular, some checkers by design
// occasionally emit their reports in empty functions (that have no
// statements in their body). Do we profile correctly in this case?
hash.AddPointer(ErrorNode->getCurrentOrPreviousStmtForDiagnostics());
}
for (SourceRange range : Ranges) {
if (!range.isValid())
continue;
hash.AddInteger(range.getBegin().getRawEncoding());
hash.AddInteger(range.getEnd().getRawEncoding());
}
}
template <class T>
static void insertToInterestingnessMap(
llvm::DenseMap<T, bugreporter::TrackingKind> &InterestingnessMap, T Val,
bugreporter::TrackingKind TKind) {
auto Result = InterestingnessMap.insert({Val, TKind});
if (Result.second)
return;
// Even if this symbol/region was already marked as interesting as a
// condition, if we later mark it as interesting again but with
// thorough tracking, overwrite it. Entities marked with thorough
// interestiness are the most important (or most interesting, if you will),
// and we wouldn't like to downplay their importance.
switch (TKind) {
case bugreporter::TrackingKind::Thorough:
Result.first->getSecond() = bugreporter::TrackingKind::Thorough;
return;
case bugreporter::TrackingKind::Condition:
return;
}
llvm_unreachable(
"BugReport::markInteresting currently can only handle 2 different "
"tracking kinds! Please define what tracking kind should this entitiy"
"have, if it was already marked as interesting with a different kind!");
}
void PathSensitiveBugReport::markInteresting(SymbolRef sym,
bugreporter::TrackingKind TKind) {
if (!sym)
return;
insertToInterestingnessMap(InterestingSymbols, sym, TKind);
if (const auto *meta = dyn_cast<SymbolMetadata>(sym))
markInteresting(meta->getRegion(), TKind);
}
void PathSensitiveBugReport::markInteresting(const MemRegion *R,
bugreporter::TrackingKind TKind) {
if (!R)
return;
R = R->getBaseRegion();
insertToInterestingnessMap(InterestingRegions, R, TKind);
if (const auto *SR = dyn_cast<SymbolicRegion>(R))
markInteresting(SR->getSymbol(), TKind);
}
void PathSensitiveBugReport::markInteresting(SVal V,
bugreporter::TrackingKind TKind) {
markInteresting(V.getAsRegion(), TKind);
markInteresting(V.getAsSymbol(), TKind);
}
void PathSensitiveBugReport::markInteresting(const LocationContext *LC) {
if (!LC)
return;
InterestingLocationContexts.insert(LC);
}
Optional<bugreporter::TrackingKind>
PathSensitiveBugReport::getInterestingnessKind(SVal V) const {
auto RKind = getInterestingnessKind(V.getAsRegion());
auto SKind = getInterestingnessKind(V.getAsSymbol());
if (!RKind)
return SKind;
if (!SKind)
return RKind;
// If either is marked with throrough tracking, return that, we wouldn't like
// to downplay a note's importance by 'only' mentioning it as a condition.
switch(*RKind) {
case bugreporter::TrackingKind::Thorough:
return RKind;
case bugreporter::TrackingKind::Condition:
return SKind;
}
llvm_unreachable(
"BugReport::getInterestingnessKind currently can only handle 2 different "
"tracking kinds! Please define what tracking kind should we return here "
"when the kind of getAsRegion() and getAsSymbol() is different!");
return None;
}
Optional<bugreporter::TrackingKind>
PathSensitiveBugReport::getInterestingnessKind(SymbolRef sym) const {
if (!sym)
return None;
// We don't currently consider metadata symbols to be interesting
// even if we know their region is interesting. Is that correct behavior?
auto It = InterestingSymbols.find(sym);
if (It == InterestingSymbols.end())
return None;
return It->getSecond();
}
Optional<bugreporter::TrackingKind>
PathSensitiveBugReport::getInterestingnessKind(const MemRegion *R) const {
if (!R)
return None;
R = R->getBaseRegion();
auto It = InterestingRegions.find(R);
if (It != InterestingRegions.end())
return It->getSecond();
if (const auto *SR = dyn_cast<SymbolicRegion>(R))
return getInterestingnessKind(SR->getSymbol());
return None;
}
bool PathSensitiveBugReport::isInteresting(SVal V) const {
return getInterestingnessKind(V).hasValue();
}
bool PathSensitiveBugReport::isInteresting(SymbolRef sym) const {
return getInterestingnessKind(sym).hasValue();
}
bool PathSensitiveBugReport::isInteresting(const MemRegion *R) const {
return getInterestingnessKind(R).hasValue();
}
bool PathSensitiveBugReport::isInteresting(const LocationContext *LC) const {
if (!LC)
return false;
return InterestingLocationContexts.count(LC);
}
const Stmt *PathSensitiveBugReport::getStmt() const {
if (!ErrorNode)
return nullptr;
ProgramPoint ProgP = ErrorNode->getLocation();
const Stmt *S = nullptr;
if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) {
CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
if (BE->getBlock() == &Exit)
S = ErrorNode->getPreviousStmtForDiagnostics();
}
if (!S)
S = ErrorNode->getStmtForDiagnostics();
return S;
}
ArrayRef<SourceRange>
PathSensitiveBugReport::getRanges() const {
// If no custom ranges, add the range of the statement corresponding to
// the error node.
if (Ranges.empty() && isa_and_nonnull<Expr>(getStmt()))
return ErrorNodeRange;
return Ranges;
}
PathDiagnosticLocation
PathSensitiveBugReport::getLocation() const {
assert(ErrorNode && "Cannot create a location with a null node.");
const Stmt *S = ErrorNode->getStmtForDiagnostics();
ProgramPoint P = ErrorNode->getLocation();
const LocationContext *LC = P.getLocationContext();
SourceManager &SM =
ErrorNode->getState()->getStateManager().getContext().getSourceManager();
if (!S) {
// If this is an implicit call, return the implicit call point location.
if (Optional<PreImplicitCall> PIE = P.getAs<PreImplicitCall>())
return PathDiagnosticLocation(PIE->getLocation(), SM);
if (auto FE = P.getAs<FunctionExitPoint>()) {
if (const ReturnStmt *RS = FE->getStmt())
return PathDiagnosticLocation::createBegin(RS, SM, LC);
}
S = ErrorNode->getNextStmtForDiagnostics();
}
if (S) {
// For member expressions, return the location of the '.' or '->'.
if (const auto *ME = dyn_cast<MemberExpr>(S))
return PathDiagnosticLocation::createMemberLoc(ME, SM);
// For binary operators, return the location of the operator.
if (const auto *B = dyn_cast<BinaryOperator>(S))
return PathDiagnosticLocation::createOperatorLoc(B, SM);
if (P.getAs<PostStmtPurgeDeadSymbols>())
return PathDiagnosticLocation::createEnd(S, SM, LC);
if (S->getBeginLoc().isValid())
return PathDiagnosticLocation(S, SM, LC);
return PathDiagnosticLocation(
PathDiagnosticLocation::getValidSourceLocation(S, LC), SM);
}
return PathDiagnosticLocation::createDeclEnd(ErrorNode->getLocationContext(),
SM);
}
//===----------------------------------------------------------------------===//
// Methods for BugReporter and subclasses.
//===----------------------------------------------------------------------===//
const ExplodedGraph &PathSensitiveBugReporter::getGraph() const {
return Eng.getGraph();
}
ProgramStateManager &PathSensitiveBugReporter::getStateManager() const {
return Eng.getStateManager();
}
BugReporter::~BugReporter() {
// Make sure reports are flushed.
assert(StrBugTypes.empty() &&
"Destroying BugReporter before diagnostics are emitted!");
// Free the bug reports we are tracking.
for (const auto I : EQClassesVector)
delete I;
}
void BugReporter::FlushReports() {
// We need to flush reports in deterministic order to ensure the order
// of the reports is consistent between runs.
for (const auto EQ : EQClassesVector)
FlushReport(*EQ);
// BugReporter owns and deletes only BugTypes created implicitly through
// EmitBasicReport.
// FIXME: There are leaks from checkers that assume that the BugTypes they
// create will be destroyed by the BugReporter.
llvm::DeleteContainerSeconds(StrBugTypes);
}
//===----------------------------------------------------------------------===//
// PathDiagnostics generation.
//===----------------------------------------------------------------------===//
namespace {
/// A wrapper around an ExplodedGraph that contains a single path from the root
/// to the error node.
class BugPathInfo {
public:
std::unique_ptr<ExplodedGraph> BugPath;
PathSensitiveBugReport *Report;
const ExplodedNode *ErrorNode;
};
/// A wrapper around an ExplodedGraph whose leafs are all error nodes. Can
/// conveniently retrieve bug paths from a single error node to the root.
class BugPathGetter {
std::unique_ptr<ExplodedGraph> TrimmedGraph;
using PriorityMapTy = llvm::DenseMap<const ExplodedNode *, unsigned>;
/// Assign each node with its distance from the root.
PriorityMapTy PriorityMap;
/// Since the getErrorNode() or BugReport refers to the original ExplodedGraph,
/// we need to pair it to the error node of the constructed trimmed graph.
using ReportNewNodePair =
std::pair<PathSensitiveBugReport *, const ExplodedNode *>;
SmallVector<ReportNewNodePair, 32> ReportNodes;
BugPathInfo CurrentBugPath;
/// A helper class for sorting ExplodedNodes by priority.
template <bool Descending>
class PriorityCompare {
const PriorityMapTy &PriorityMap;
public:
PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {}
bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const {
PriorityMapTy::const_iterator LI = PriorityMap.find(LHS);
PriorityMapTy::const_iterator RI = PriorityMap.find(RHS);
PriorityMapTy::const_iterator E = PriorityMap.end();
if (LI == E)
return Descending;
if (RI == E)
return !Descending;
return Descending ? LI->second > RI->second
: LI->second < RI->second;
}
bool operator()(const ReportNewNodePair &LHS,
const ReportNewNodePair &RHS) const {
return (*this)(LHS.second, RHS.second);
}
};
public:
BugPathGetter(const ExplodedGraph *OriginalGraph,
ArrayRef<PathSensitiveBugReport *> &bugReports);
BugPathInfo *getNextBugPath();
};
} // namespace
BugPathGetter::BugPathGetter(const ExplodedGraph *OriginalGraph,
ArrayRef<PathSensitiveBugReport *> &bugReports) {
SmallVector<const ExplodedNode *, 32> Nodes;
for (const auto I : bugReports) {
assert(I->isValid() &&
"We only allow BugReporterVisitors and BugReporter itself to "
"invalidate reports!");
Nodes.emplace_back(I->getErrorNode());
}
// The trimmed graph is created in the body of the constructor to ensure
// that the DenseMaps have been initialized already.
InterExplodedGraphMap ForwardMap;
TrimmedGraph = OriginalGraph->trim(Nodes, &ForwardMap);
// Find the (first) error node in the trimmed graph. We just need to consult
// the node map which maps from nodes in the original graph to nodes
// in the new graph.
llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes;
for (PathSensitiveBugReport *Report : bugReports) {
const ExplodedNode *NewNode = ForwardMap.lookup(Report->getErrorNode());
assert(NewNode &&
"Failed to construct a trimmed graph that contains this error "
"node!");
ReportNodes.emplace_back(Report, NewNode);
RemainingNodes.insert(NewNode);
}
assert(!RemainingNodes.empty() && "No error node found in the trimmed graph");
// Perform a forward BFS to find all the shortest paths.
std::queue<const ExplodedNode *> WS;
assert(TrimmedGraph->num_roots() == 1);
WS.push(*TrimmedGraph->roots_begin());
unsigned Priority = 0;
while (!WS.empty()) {
const ExplodedNode *Node = WS.front();
WS.pop();
PriorityMapTy::iterator PriorityEntry;
bool IsNew;
std::tie(PriorityEntry, IsNew) = PriorityMap.insert({Node, Priority});
++Priority;
if (!IsNew) {
assert(PriorityEntry->second <= Priority);
continue;
}
if (RemainingNodes.erase(Node))
if (RemainingNodes.empty())
break;
for (const ExplodedNode *Succ : Node->succs())
WS.push(Succ);
}
// Sort the error paths from longest to shortest.
llvm::sort(ReportNodes, PriorityCompare<true>(PriorityMap));
}
BugPathInfo *BugPathGetter::getNextBugPath() {
if (ReportNodes.empty())
return nullptr;
const ExplodedNode *OrigN;
std::tie(CurrentBugPath.Report, OrigN) = ReportNodes.pop_back_val();
assert(PriorityMap.find(OrigN) != PriorityMap.end() &&
"error node not accessible from root");
// Create a new graph with a single path. This is the graph that will be
// returned to the caller.
auto GNew = std::make_unique<ExplodedGraph>();
// Now walk from the error node up the BFS path, always taking the
// predeccessor with the lowest number.
ExplodedNode *Succ = nullptr;
while (true) {
// Create the equivalent node in the new graph with the same state
// and location.
ExplodedNode *NewN = GNew->createUncachedNode(
OrigN->getLocation(), OrigN->getState(),
OrigN->getID(), OrigN->isSink());
// Link up the new node with the previous node.
if (Succ)
Succ->addPredecessor(NewN, *GNew);
else
CurrentBugPath.ErrorNode = NewN;
Succ = NewN;
// Are we at the final node?
if (OrigN->pred_empty()) {
GNew->addRoot(NewN);
break;
}
// Find the next predeccessor node. We choose the node that is marked
// with the lowest BFS number.
OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(),
PriorityCompare<false>(PriorityMap));
}
CurrentBugPath.BugPath = std::move(GNew);
return &CurrentBugPath;
}
/// CompactMacroExpandedPieces - This function postprocesses a PathDiagnostic
/// object and collapses PathDiagosticPieces that are expanded by macros.
static void CompactMacroExpandedPieces(PathPieces &path,
const SourceManager& SM) {
using MacroStackTy = std::vector<
std::pair<std::shared_ptr<PathDiagnosticMacroPiece>, SourceLocation>>;
using PiecesTy = std::vector<PathDiagnosticPieceRef>;
MacroStackTy MacroStack;
PiecesTy Pieces;
for (PathPieces::const_iterator I = path.begin(), E = path.end();
I != E; ++I) {
const auto &piece = *I;
// Recursively compact calls.
if (auto *call = dyn_cast<PathDiagnosticCallPiece>(&*piece)) {
CompactMacroExpandedPieces(call->path, SM);
}
// Get the location of the PathDiagnosticPiece.
const FullSourceLoc Loc = piece->getLocation().asLocation();
// Determine the instantiation location, which is the location we group
// related PathDiagnosticPieces.
SourceLocation InstantiationLoc = Loc.isMacroID() ?
SM.getExpansionLoc(Loc) :
SourceLocation();
if (Loc.isFileID()) {
MacroStack.clear();
Pieces.push_back(piece);
continue;
}
assert(Loc.isMacroID());
// Is the PathDiagnosticPiece within the same macro group?
if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
MacroStack.back().first->subPieces.push_back(piece);
continue;
}
// We aren't in the same group. Are we descending into a new macro
// or are part of an old one?
std::shared_ptr<PathDiagnosticMacroPiece> MacroGroup;
SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
SM.getExpansionLoc(Loc) :
SourceLocation();
// Walk the entire macro stack.
while (!MacroStack.empty()) {
if (InstantiationLoc == MacroStack.back().second) {
MacroGroup = MacroStack.back().first;
break;
}
if (ParentInstantiationLoc == MacroStack.back().second) {
MacroGroup = MacroStack.back().first;
break;
}
MacroStack.pop_back();
}
if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
// Create a new macro group and add it to the stack.
auto NewGroup = std::make_shared<PathDiagnosticMacroPiece>(
PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
if (MacroGroup)
MacroGroup->subPieces.push_back(NewGroup);
else {
assert(InstantiationLoc.isFileID());
Pieces.push_back(NewGroup);
}
MacroGroup = NewGroup;
MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
}
// Finally, add the PathDiagnosticPiece to the group.
MacroGroup->subPieces.push_back(piece);
}
// Now take the pieces and construct a new PathDiagnostic.
path.clear();
path.insert(path.end(), Pieces.begin(), Pieces.end());
}
/// Generate notes from all visitors.
/// Notes associated with {@code ErrorNode} are generated using
/// {@code getEndPath}, and the rest are generated with {@code VisitNode}.
static std::unique_ptr<VisitorsDiagnosticsTy>
generateVisitorsDiagnostics(PathSensitiveBugReport *R,
const ExplodedNode *ErrorNode,
BugReporterContext &BRC) {
std::unique_ptr<VisitorsDiagnosticsTy> Notes =
std::make_unique<VisitorsDiagnosticsTy>();
PathSensitiveBugReport::VisitorList visitors;
// Run visitors on all nodes starting from the node *before* the last one.
// The last node is reserved for notes generated with {@code getEndPath}.
const ExplodedNode *NextNode = ErrorNode->getFirstPred();
while (NextNode) {
// At each iteration, move all visitors from report to visitor list. This is
// important, because the Profile() functions of the visitors make sure that
// a visitor isn't added multiple times for the same node, but it's fine
// to add the a visitor with Profile() for different nodes (e.g. tracking
// a region at different points of the symbolic execution).
for (std::unique_ptr<BugReporterVisitor> &Visitor : R->visitors())
visitors.push_back(std::move(Visitor));
R->clearVisitors();
const ExplodedNode *Pred = NextNode->getFirstPred();
if (!Pred) {
PathDiagnosticPieceRef LastPiece;
for (auto &V : visitors) {
V->finalizeVisitor(BRC, ErrorNode, *R);
if (auto Piece = V->getEndPath(BRC, ErrorNode, *R)) {
assert(!LastPiece &&
"There can only be one final piece in a diagnostic.");
assert(Piece->getKind() == PathDiagnosticPiece::Kind::Event &&
"The final piece must contain a message!");
LastPiece = std::move(Piece);
(*Notes)[ErrorNode].push_back(LastPiece);
}
}
break;
}
for (auto &V : visitors) {
auto P = V->VisitNode(NextNode, BRC, *R);
if (P)
(*Notes)[NextNode].push_back(std::move(P));
}
if (!R->isValid())
break;
NextNode = Pred;
}
return Notes;
}
Optional<PathDiagnosticBuilder> PathDiagnosticBuilder::findValidReport(
ArrayRef<PathSensitiveBugReport *> &bugReports,
PathSensitiveBugReporter &Reporter) {
BugPathGetter BugGraph(&Reporter.getGraph(), bugReports);
while (BugPathInfo *BugPath = BugGraph.getNextBugPath()) {
// Find the BugReport with the original location.
PathSensitiveBugReport *R = BugPath->Report;
assert(R && "No original report found for sliced graph.");
assert(R->isValid() && "Report selected by trimmed graph marked invalid.");
const ExplodedNode *ErrorNode = BugPath->ErrorNode;
// Register refutation visitors first, if they mark the bug invalid no
// further analysis is required
R->addVisitor(std::make_unique<LikelyFalsePositiveSuppressionBRVisitor>());
// Register additional node visitors.
R->addVisitor(std::make_unique<NilReceiverBRVisitor>());
R->addVisitor(std::make_unique<ConditionBRVisitor>());
R->addVisitor(std::make_unique<TagVisitor>());
BugReporterContext BRC(Reporter);
// Run all visitors on a given graph, once.
std::unique_ptr<VisitorsDiagnosticsTy> visitorNotes =
generateVisitorsDiagnostics(R, ErrorNode, BRC);
if (R->isValid()) {
if (Reporter.getAnalyzerOptions().ShouldCrosscheckWithZ3) {
// If crosscheck is enabled, remove all visitors, add the refutation
// visitor and check again
R->clearVisitors();
R->addVisitor(std::make_unique<FalsePositiveRefutationBRVisitor>());
// We don't overrite the notes inserted by other visitors because the
// refutation manager does not add any new note to the path
generateVisitorsDiagnostics(R, BugPath->ErrorNode, BRC);
}
// Check if the bug is still valid
if (R->isValid())
return PathDiagnosticBuilder(
std::move(BRC), std::move(BugPath->BugPath), BugPath->Report,
BugPath->ErrorNode, std::move(visitorNotes));
}
}
return {};
}
std::unique_ptr<DiagnosticForConsumerMapTy>
PathSensitiveBugReporter::generatePathDiagnostics(
ArrayRef<PathDiagnosticConsumer *> consumers,
ArrayRef<PathSensitiveBugReport *> &bugReports) {
assert(!bugReports.empty());
auto Out = std::make_unique<DiagnosticForConsumerMapTy>();
Optional<PathDiagnosticBuilder> PDB =
PathDiagnosticBuilder::findValidReport(bugReports, *this);
if (PDB) {
for (PathDiagnosticConsumer *PC : consumers) {
if (std::unique_ptr<PathDiagnostic> PD = PDB->generate(PC)) {
(*Out)[PC] = std::move(PD);
}
}
}
return Out;
}
void BugReporter::emitReport(std::unique_ptr<BugReport> R