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// BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- C++ -*--//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines BugReporter, a utility class for generating
// PathDiagnostics.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/CFGStmtMap.h"
#include "clang/Analysis/ProgramPoint.h"
#include "clang/Basic/SourceManager.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/raw_ostream.h"
#include <memory>
#include <queue>
using namespace clang;
using namespace ento;
#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() {}
void BugReporterContext::anchor() {}
//===----------------------------------------------------------------------===//
// Helper routines for walking the ExplodedGraph and fetching statements.
//===----------------------------------------------------------------------===//
static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
for (N = N->getFirstPred(); N; N = N->getFirstPred())
if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
return S;
return nullptr;
}
static inline const Stmt*
GetCurrentOrPreviousStmt(const ExplodedNode *N) {
if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
return S;
return GetPreviousStmt(N);
}
//===----------------------------------------------------------------------===//
// 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::ControlFlow:
break;
case PathDiagnosticPiece::Event: {
if (i == N-1)
break;
if (PathDiagnosticEventPiece *nextEvent =
dyn_cast<PathDiagnosticEventPiece>(path.front().get())) {
PathDiagnosticEventPiece *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::Note:
break;
}
path.push_back(std::move(piece));
}
}
/// A map from PathDiagnosticPiece to the LocationContext of the inlined
/// function call it represents.
typedef llvm::DenseMap<const PathPieces *, const LocationContext *>
LocationContextMap;
/// 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(PathPieces &pieces, BugReport *R,
LocationContextMap &LCM) {
bool containsSomethingInteresting = false;
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.
assert(LCM.count(&call.path));
if (R->isInteresting(LCM[&call.path])) {
containsSomethingInteresting = true;
break;
}
if (!removeUnneededCalls(call.path, R, LCM))
continue;
containsSomethingInteresting = true;
break;
}
case PathDiagnosticPiece::Macro: {
auto &macro = cast<PathDiagnosticMacroPiece>(*piece);
if (!removeUnneededCalls(macro.subPieces, R, LCM))
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:
break;
case PathDiagnosticPiece::Note:
break;
}
pieces.push_back(std::move(piece));
}
return containsSomethingInteresting;
}
/// 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 (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) {
PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(I->get());
if (!Call) {
assert((*I)->getLocation().asLocation().isValid());
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++;
}
}
//===----------------------------------------------------------------------===//
// PathDiagnosticBuilder and its associated routines and helper objects.
//===----------------------------------------------------------------------===//
namespace {
class NodeMapClosure : public BugReport::NodeResolver {
InterExplodedGraphMap &M;
public:
NodeMapClosure(InterExplodedGraphMap &m) : M(m) {}
const ExplodedNode *getOriginalNode(const ExplodedNode *N) override {
return M.lookup(N);
}
};
class PathDiagnosticBuilder : public BugReporterContext {
BugReport *R;
PathDiagnosticConsumer *PDC;
NodeMapClosure NMC;
public:
const LocationContext *LC;
PathDiagnosticBuilder(GRBugReporter &br,
BugReport *r, InterExplodedGraphMap &Backmap,
PathDiagnosticConsumer *pdc)
: BugReporterContext(br),
R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext())
{}
PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
const ExplodedNode *N);
BugReport *getBugReport() { return R; }
Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
ParentMap& getParentMap() { return LC->getParentMap(); }
const Stmt *getParent(const Stmt *S) {
return getParentMap().getParent(S);
}
NodeMapClosure& getNodeResolver() override { return NMC; }
PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const {
return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive;
}
bool supportsLogicalOpControlFlow() const {
return PDC ? PDC->supportsLogicalOpControlFlow() : true;
}
};
} // end anonymous namespace
PathDiagnosticLocation
PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N))
return PathDiagnosticLocation(S, getSourceManager(), LC);
return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(),
getSourceManager());
}
PathDiagnosticLocation
PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
const ExplodedNode *N) {
// Slow, but probably doesn't matter.
if (os.str().empty())
os << ' ';
const PathDiagnosticLocation &Loc = ExecutionContinues(N);
if (Loc.asStmt())
os << "Execution continues on line "
<< getSourceManager().getExpansionLineNumber(Loc.asLocation())
<< '.';
else {
os << "Execution jumps to the end of the ";
const Decl *D = N->getLocationContext()->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, SourceManager &SMgr, const ParentMap &P,
const LocationContext *LC, bool allowNestedContexts) {
if (!S)
return PathDiagnosticLocation();
while (const Stmt *Parent = getEnclosingParent(S, P)) {
switch (Parent->getStmtClass()) {
case Stmt::BinaryOperatorClass: {
const BinaryOperator *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);
}
PathDiagnosticLocation
PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
assert(S && "Null Stmt passed to getEnclosingStmtLocation");
return ::getEnclosingStmtLocation(S, getSourceManager(), getParentMap(), LC,
/*allowNestedContexts=*/false);
}
//===----------------------------------------------------------------------===//
// "Visitors only" path diagnostic generation algorithm.
//===----------------------------------------------------------------------===//
static bool GenerateVisitorsOnlyPathDiagnostic(
PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
// All path generation skips the very first node (the error node).
// This is because there is special handling for the end-of-path note.
N = N->getFirstPred();
if (!N)
return true;
BugReport *R = PDB.getBugReport();
while (const ExplodedNode *Pred = N->getFirstPred()) {
for (auto &V : visitors)
// Visit all the node pairs, but throw the path pieces away.
V->VisitNode(N, Pred, PDB, *R);
N = Pred;
}
return R->isValid();
}
//===----------------------------------------------------------------------===//
// "Minimal" path diagnostic generation algorithm.
//===----------------------------------------------------------------------===//
typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair;
typedef SmallVector<StackDiagPair, 6> StackDiagVector;
static void updateStackPiecesWithMessage(PathDiagnosticPiece &P,
StackDiagVector &CallStack) {
// If the piece contains a special message, add it to all the call
// pieces on the active stack.
if (PathDiagnosticEventPiece *ep = dyn_cast<PathDiagnosticEventPiece>(&P)) {
if (ep->hasCallStackHint())
for (StackDiagVector::iterator I = CallStack.begin(),
E = CallStack.end(); I != E; ++I) {
PathDiagnosticCallPiece *CP = I->first;
const ExplodedNode *N = I->second;
std::string stackMsg = ep->getCallStackMessage(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 CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
static bool GenerateMinimalPathDiagnostic(
PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
LocationContextMap &LCM,
ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
SourceManager& SMgr = PDB.getSourceManager();
const LocationContext *LC = PDB.LC;
const ExplodedNode *NextNode = N->pred_empty()
? nullptr : *(N->pred_begin());
StackDiagVector CallStack;
while (NextNode) {
N = NextNode;
PDB.LC = N->getLocationContext();
NextNode = N->getFirstPred();
ProgramPoint P = N->getLocation();
do {
if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
auto C = PathDiagnosticCallPiece::construct(N, *CE, SMgr);
// Record the mapping from call piece to LocationContext.
LCM[&C->path] = CE->getCalleeContext();
auto *P = C.get();
PD.getActivePath().push_front(std::move(C));
PD.pushActivePath(&P->path);
CallStack.push_back(StackDiagPair(P, N));
break;
}
if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
// Flush all locations, and pop the active path.
bool VisitedEntireCall = PD.isWithinCall();
PD.popActivePath();
// Either we just added a bunch of stuff to the top-level path, or
// we have a previous CallExitEnd. If the former, it means that the
// path terminated within a function call. We must then take the
// current contents of the active path and place it within
// a new PathDiagnosticCallPiece.
PathDiagnosticCallPiece *C;
if (VisitedEntireCall) {
C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
} else {
const Decl *Caller = CE->getLocationContext()->getDecl();
C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
// Record the mapping from call piece to LocationContext.
LCM[&C->path] = CE->getCalleeContext();
}
C->setCallee(*CE, SMgr);
if (!CallStack.empty()) {
assert(CallStack.back().first == C);
CallStack.pop_back();
}
break;
}
if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
const CFGBlock *Src = BE->getSrc();
const CFGBlock *Dst = BE->getDst();
const Stmt *T = Src->getTerminator();
if (!T)
break;
PathDiagnosticLocation Start =
PathDiagnosticLocation::createBegin(T, SMgr,
N->getLocationContext());
switch (T->getStmtClass()) {
default:
break;
case Stmt::GotoStmtClass:
case Stmt::IndirectGotoStmtClass: {
const Stmt *S = PathDiagnosticLocation::getNextStmt(N);
if (!S)
break;
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
os << "Control jumps to line "
<< End.asLocation().getExpansionLineNumber();
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
break;
}
case Stmt::SwitchStmtClass: {
// Figure out what case arm we took.
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
if (const Stmt *S = Dst->getLabel()) {
PathDiagnosticLocation End(S, SMgr, LC);
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 CaseStmt *Case = cast<CaseStmt>(S);
const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
// Determine if it is an enum.
bool GetRawInt = true;
if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
// FIXME: Maybe this should be an assertion. Are there cases
// were it is not an EnumConstantDecl?
const EnumConstantDecl *D =
dyn_cast<EnumConstantDecl>(DR->getDecl());
if (D) {
GetRawInt = false;
os << *D;
}
}
if (GetRawInt)
os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
os << ":' at line "
<< End.asLocation().getExpansionLineNumber();
break;
}
}
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
else {
os << "'Default' branch taken. ";
const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
break;
}
case Stmt::BreakStmtClass:
case Stmt::ContinueStmtClass: {
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
PD.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 = PDB.ExecutionContinues(N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
break;
}
// Determine control-flow for short-circuited '&&' and '||'.
case Stmt::BinaryOperatorClass: {
if (!PDB.supportsLogicalOpControlFlow())
break;
const BinaryOperator *B = cast<BinaryOperator>(T);
std::string sbuf;
llvm::raw_string_ostream os(sbuf);
os << "Left side of '";
if (B->getOpcode() == BO_LAnd) {
os << "&&" << "' is ";
if (*(Src->succ_begin()+1) == Dst) {
os << "false";
PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
PathDiagnosticLocation Start =
PathDiagnosticLocation::createOperatorLoc(B, SMgr);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
else {
os << "true";
PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
PathDiagnosticLocation End = PDB.ExecutionContinues(N);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
}
else {
assert(B->getOpcode() == BO_LOr);
os << "||" << "' is ";
if (*(Src->succ_begin()+1) == Dst) {
os << "false";
PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
PathDiagnosticLocation End = PDB.ExecutionContinues(N);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
else {
os << "true";
PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
PathDiagnosticLocation Start =
PathDiagnosticLocation::createOperatorLoc(B, SMgr);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
}
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 = PDB.ExecutionContinues(os, N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
else {
PathDiagnosticLocation End = PDB.ExecutionContinues(N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
PD.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 = PDB.ExecutionContinues(os, N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
os.str()));
}
else {
PathDiagnosticLocation End = PDB.ExecutionContinues(N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Loop condition is true. Entering loop body"));
}
break;
}
case Stmt::IfStmtClass: {
PathDiagnosticLocation End = PDB.ExecutionContinues(N);
if (const Stmt *S = End.asStmt())
End = PDB.getEnclosingStmtLocation(S);
if (*(Src->succ_begin()+1) == Dst)
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Taking false branch"));
else
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(
Start, End, "Taking true branch"));
break;
}
}
}
} while(0);
if (NextNode) {
// Add diagnostic pieces from custom visitors.
BugReport *R = PDB.getBugReport();
for (auto &V : visitors) {
if (auto p = V->VisitNode(N, NextNode, PDB, *R)) {
updateStackPiecesWithMessage(*p, CallStack);
PD.getActivePath().push_front(std::move(p));
}
}
}
}
if (!PDB.getBugReport()->isValid())
return false;
// After constructing the full PathDiagnostic, do a pass over it to compact
// PathDiagnosticPieces that occur within a macro.
CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager());
return true;
}
//===----------------------------------------------------------------------===//
// "Extensive" PathDiagnostic generation.
//===----------------------------------------------------------------------===//
static bool IsControlFlowExpr(const Stmt *S) {
const Expr *E = dyn_cast<Expr>(S);
if (!E)
return false;
E = E->IgnoreParenCasts();
if (isa<AbstractConditionalOperator>(E))
return true;
if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
if (B->isLogicalOp())
return true;
return false;
}
namespace {
class ContextLocation : public PathDiagnosticLocation {
bool IsDead;
public:
ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
: PathDiagnosticLocation(L), IsDead(isdead) {}
void markDead() { IsDead = true; }
bool isDead() const { return IsDead; }
};
static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
const LocationContext *LC,
bool firstCharOnly = false) {
if (const Stmt *S = L.asStmt()) {
const Stmt *Original = S;
while (1) {
// Adjust the location for some expressions that are best referenced
// by one of their subexpressions.
switch (S->getStmtClass()) {
default:
break;
case Stmt::ParenExprClass:
case Stmt::GenericSelectionExprClass:
S = cast<Expr>(S)->IgnoreParens();
firstCharOnly = true;
continue;
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass:
S = cast<AbstractConditionalOperator>(S)->getCond();
firstCharOnly = true;
continue;
case Stmt::ChooseExprClass:
S = cast<ChooseExpr>(S)->getCond();
firstCharOnly = true;
continue;
case Stmt::BinaryOperatorClass:
S = cast<BinaryOperator>(S)->getLHS();
firstCharOnly = true;
continue;
}
break;
}
if (S != Original)
L = PathDiagnosticLocation(S, L.getManager(), LC);
}
if (firstCharOnly)
L = PathDiagnosticLocation::createSingleLocation(L);
return L;
}
class EdgeBuilder {
std::vector<ContextLocation> CLocs;
typedef std::vector<ContextLocation>::iterator iterator;
PathDiagnostic &PD;
PathDiagnosticBuilder &PDB;
PathDiagnosticLocation PrevLoc;
bool IsConsumedExpr(const PathDiagnosticLocation &L);
bool containsLocation(const PathDiagnosticLocation &Container,
const PathDiagnosticLocation &Containee);
PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
void popLocation() {
if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
// For contexts, we only one the first character as the range.
rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true));
}
CLocs.pop_back();
}
public:
EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
: PD(pd), PDB(pdb) {
// If the PathDiagnostic already has pieces, add the enclosing statement
// of the first piece as a context as well.
if (!PD.path.empty()) {
PrevLoc = (*PD.path.begin())->getLocation();
if (const Stmt *S = PrevLoc.asStmt())
addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
}
}
~EdgeBuilder() {
while (!CLocs.empty()) popLocation();
// Finally, add an initial edge from the start location of the first
// statement (if it doesn't already exist).
PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin(
PDB.LC,
PDB.getSourceManager());
if (L.isValid())
rawAddEdge(L);
}
void flushLocations() {
while (!CLocs.empty())
popLocation();
PrevLoc = PathDiagnosticLocation();
}
void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false,
bool IsPostJump = false);
void rawAddEdge(PathDiagnosticLocation NewLoc);
void addContext(const Stmt *S);
void addContext(const PathDiagnosticLocation &L);
void addExtendedContext(const Stmt *S);
};
} // end anonymous namespace
PathDiagnosticLocation
EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
if (const Stmt *S = L.asStmt()) {
if (IsControlFlowExpr(S))
return L;
return PDB.getEnclosingStmtLocation(S);
}
return L;
}
bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
const PathDiagnosticLocation &Containee) {
if (Container == Containee)
return true;
if (Container.asDecl())
return true;
if (const Stmt *S = Containee.asStmt())
if (const Stmt *ContainerS = Container.asStmt()) {
while (S) {
if (S == ContainerS)
return true;
S = PDB.getParent(S);
}
return false;
}
// Less accurate: compare using source ranges.
SourceRange ContainerR = Container.asRange();
SourceRange ContaineeR = Containee.asRange();
SourceManager &SM = PDB.getSourceManager();
SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
assert(ContainerBegLine <= ContainerEndLine);
assert(ContaineeBegLine <= ContaineeEndLine);
return (ContainerBegLine <= ContaineeBegLine &&
ContainerEndLine >= ContaineeEndLine &&
(ContainerBegLine != ContaineeBegLine ||
SM.getExpansionColumnNumber(ContainerRBeg) <=
SM.getExpansionColumnNumber(ContaineeRBeg)) &&
(ContainerEndLine != ContaineeEndLine ||
SM.getExpansionColumnNumber(ContainerREnd) >=
SM.getExpansionColumnNumber(ContaineeREnd)));
}
void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
if (!PrevLoc.isValid()) {
PrevLoc = NewLoc;
return;
}
const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC);
const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC);
if (PrevLocClean.asLocation().isInvalid()) {
PrevLoc = NewLoc;
return;
}
if (NewLocClean.asLocation() == PrevLocClean.asLocation())
return;
// FIXME: Ignore intra-macro edges for now.
if (NewLocClean.asLocation().getExpansionLoc() ==
PrevLocClean.asLocation().getExpansionLoc())
return;
PD.getActivePath().push_front(
std::make_shared<PathDiagnosticControlFlowPiece>(NewLocClean,
PrevLocClean));
PrevLoc = NewLoc;
}
void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd,
bool IsPostJump) {
if (!alwaysAdd && NewLoc.asLocation().isMacroID())
return;
const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
while (!CLocs.empty()) {
ContextLocation &TopContextLoc = CLocs.back();
// Is the top location context the same as the one for the new location?
if (TopContextLoc == CLoc) {
if (alwaysAdd) {
if (IsConsumedExpr(TopContextLoc))
TopContextLoc.markDead();
rawAddEdge(NewLoc);
}
if (IsPostJump)
TopContextLoc.markDead();
return;
}
if (containsLocation(TopContextLoc, CLoc)) {
if (alwaysAdd) {
rawAddEdge(NewLoc);
if (IsConsumedExpr(CLoc)) {
CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true));
return;
}
}
CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump));
return;
}
// Context does not contain the location. Flush it.
popLocation();
}
// If we reach here, there is no enclosing context. Just add the edge.
rawAddEdge(NewLoc);
}
bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
return false;
}
void EdgeBuilder::addExtendedContext(const Stmt *S) {
if (!S)
return;
const Stmt *Parent = PDB.getParent(S);
while (Parent) {
if (isa<CompoundStmt>(Parent))
Parent = PDB.getParent(Parent);
else
break;
}
if (Parent) {
switch (Parent->getStmtClass()) {
case Stmt::DoStmtClass:
case Stmt::ObjCAtSynchronizedStmtClass:
addContext(Parent);
default:
break;
}
}
addContext(S);
}
void EdgeBuilder::addContext(const Stmt *S) {
if (!S)
return;
PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
addContext(L);
}
void EdgeBuilder::addContext(const PathDiagnosticLocation &L) {
while (!CLocs.empty()) {
const PathDiagnosticLocation &TopContextLoc = CLocs.back();
// Is the top location context the same as the one for the new location?
if (TopContextLoc == L)
return;
if (containsLocation(TopContextLoc, L)) {
CLocs.push_back(L);
return;
}
// Context does not contain the location. Flush it.
popLocation();
}
CLocs.push_back(L);
}
// Cone-of-influence: support the reverse propagation of "interesting" symbols
// and values by tracing interesting calculations backwards through evaluated
// expressions along a path. This is probably overly complicated, but the idea
// is that if an expression computed an "interesting" value, the child
// expressions are are also likely to be "interesting" as well (which then
// propagates to the values they in turn compute). This reverse propagation
// is needed to track interesting correlations across function call boundaries,
// where formal arguments bind to actual arguments, etc. This is also needed
// because the constraint solver sometimes simplifies certain symbolic values
// into constants when appropriate, and this complicates reasoning about
// interesting values.
typedef llvm::DenseSet<const Expr *> InterestingExprs;
static void reversePropagateIntererstingSymbols(BugReport &R,
InterestingExprs &IE,
const ProgramState *State,
const Expr *Ex,
const LocationContext *LCtx) {
SVal V = State->getSVal(Ex, LCtx);
if (!(R.isInteresting(V) || IE.count(Ex)))
return;
switch (Ex->getStmtClass()) {
default:
if (!isa<CastExpr>(Ex))
break;
// Fall through.
case Stmt::BinaryOperatorClass:
case Stmt::UnaryOperatorClass: {
for (const Stmt *SubStmt : Ex->children()) {
if (const Expr *child = dyn_cast_or_null<Expr>(SubStmt)) {
IE.insert(child);
SVal ChildV = State->getSVal(child, LCtx);
R.markInteresting(ChildV);
}
}
break;
}
}
R.markInteresting(V);
}
static void reversePropagateInterestingSymbols(BugReport &R,
InterestingExprs &IE,
const ProgramState *State,
const LocationContext *CalleeCtx,
const LocationContext *CallerCtx)
{
// FIXME: Handle non-CallExpr-based CallEvents.
const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame();
const Stmt *CallSite = Callee->getCallSite();
if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) {
FunctionDecl::param_const_iterator PI = FD->param_begin(),
PE = FD->param_end();
CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
for (; AI != AE && PI != PE; ++AI, ++PI) {
if (const Expr *ArgE = *AI) {
if (const ParmVarDecl *PD = *PI) {
Loc LV = State->getLValue(PD, CalleeCtx);
if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV)))
IE.insert(ArgE);
}
}
}
}
}
}
//===----------------------------------------------------------------------===//
// 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());
}
/// Return true if the terminator is a loop and the destination is the
/// false branch.
static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) {
if (!isLoop(Term))
return false;
// Did we take the false branch?
return isJumpToFalseBranch(BE);
}
static bool isContainedByStmt(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(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(ParentMap &PM, const Stmt *S, const Stmt *Term) {
const Stmt *LoopBody = nullptr;
switch (Term->getStmtClass()) {
case Stmt::CXXForRangeStmtClass: {
const CXXForRangeStmt *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 ForStmt *FS = cast<ForStmt>(Term);
if (isContainedByStmt(PM, FS->getInc(), S))
return true;
LoopBody = FS->getBody();
break;
}
case Stmt::ObjCForCollectionStmtClass: {
const ObjCForCollectionStmt *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);
}
//===----------------------------------------------------------------------===//
// Top-level logic for generating extensive path diagnostics.
//===----------------------------------------------------------------------===//
static bool GenerateExtensivePathDiagnostic(
PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
LocationContextMap &LCM,
ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
EdgeBuilder EB(PD, PDB);
const SourceManager& SM = PDB.getSourceManager();
StackDiagVector CallStack;
InterestingExprs IE;
const ExplodedNode *NextNode = N->pred_empty() ? nullptr : *(N->pred_begin());
while (NextNode) {
N = NextNode;
NextNode = N->getFirstPred();
ProgramPoint P = N->getLocation();
do {
if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
if (const Expr *Ex = PS->getStmtAs<Expr>())
reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
N->getState().get(), Ex,
N->getLocationContext());
}
if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
const Stmt *S = CE->getCalleeContext()->getCallSite();
if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
N->getState().get(), Ex,
N->getLocationContext());
}
auto C = PathDiagnosticCallPiece::construct(N, *CE, SM);
LCM[&C->path] = CE->getCalleeContext();
EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true);
EB.flushLocations();
auto *P = C.get();
PD.getActivePath().push_front(std::move(C));
PD.pushActivePath(&P->path);
CallStack.push_back(StackDiagPair(P, N));
break;
}
// Pop the call hierarchy if we are done walking the contents
// of a function call.
if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
// Add an edge to the start of the function.
const Decl *D = CE->getCalleeContext()->getDecl();
PathDiagnosticLocation pos =
PathDiagnosticLocation::createBegin(D, SM);
EB.addEdge(pos);
// Flush all locations, and pop the active path.
bool VisitedEntireCall = PD.isWithinCall();
EB.flushLocations();
PD.popActivePath();
PDB.LC = N->getLocationContext();
// Either we just added a bunch of stuff to the top-level path, or
// we have a previous CallExitEnd. If the former, it means that the
// path terminated within a function call. We must then take the
// current contents of the active path and place it within
// a new PathDiagnosticCallPiece.
PathDiagnosticCallPiece *C;
if (VisitedEntireCall) {
C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
} else {
const Decl *Caller = CE->getLocationContext()->getDecl();
C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
LCM[&C->path] = CE->getCalleeContext();
}
C->setCallee(*CE, SM);
EB.addContext(C->getLocation());
if (!CallStack.empty()) {
assert(CallStack.back().first == C);
CallStack.pop_back();
}
break;
}
// Note that is important that we update the LocationContext
// after looking at CallExits. CallExit basically adds an
// edge in the *caller*, so we don't want to update the LocationContext
// too soon.
PDB.LC = N->getLocationContext();
// Block edges.
if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
// Does this represent entering a call? If so, look at propagating
// interesting symbols across call boundaries.
if (NextNode) {
const LocationContext *CallerCtx = NextNode->getLocationContext();
const LocationContext *CalleeCtx = PDB.LC;
if (CallerCtx != CalleeCtx) {
reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
N->getState().get(),
CalleeCtx, CallerCtx);
}
}
// Are we jumping to the head of a loop? Add a special diagnostic.
if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
PathDiagnosticLocation L(Loop, SM, PDB.LC);
const CompoundStmt *CS = nullptr;
if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
CS = dyn_cast<CompoundStmt>(FS->getBody());
else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
CS = dyn_cast<CompoundStmt>(WS->getBody());
auto p = std::make_shared<PathDiagnosticEventPiece>(
L, "Looping back to the head of the loop");
p->setPrunable(true);
EB.addEdge(p->getLocation(), true);
PD.getActivePath().push_front(std::move(p));
if (CS) {
PathDiagnosticLocation BL =
PathDiagnosticLocation::createEndBrace(CS, SM);
EB.addEdge(BL);
}
}
const CFGBlock *BSrc = BE->getSrc();
ParentMap &PM = PDB.getParentMap();
if (const Stmt *Term = BSrc->getTerminator()) {
// Are we jumping past the loop body without ever executing the
// loop (because the condition was false)?
if (isLoopJumpPastBody(Term, &*BE) &&
!isInLoopBody(PM,
getStmtBeforeCond(PM,
BSrc->getTerminatorCondition(),
N),
Term)) {
PathDiagnosticLocation L(Term, SM, PDB.LC);
auto PE = std::make_shared<PathDiagnosticEventPiece>(
L, "Loop body executed 0 times");
PE->setPrunable(true);
EB.addEdge(PE->getLocation(), true);
PD.getActivePath().push_front(std::move(PE));
}
// In any case, add the terminator as the current statement
// context for control edges.
EB.addContext(Term);
}
break;
}
if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
Optional<CFGElement> First = BE->getFirstElement();
if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) {
const Stmt *stmt = S->getStmt();
if (IsControlFlowExpr(stmt)) {
// Add the proper context for '&&', '||', and '?'.
EB.addContext(stmt);
}
else
EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
}
break;
}
} while (0);
if (!NextNode)
continue;
// Add pieces from custom visitors.
BugReport *R = PDB.getBugReport();
for (auto &V : visitors) {
if (auto p = V->VisitNode(N, NextNode, PDB, *R)) {
const PathDiagnosticLocation &Loc = p->getLocation();
EB.addEdge(Loc, true);
updateStackPiecesWithMessage(*p, CallStack);
PD.getActivePath().push_front(std::move(p));
if (const Stmt *S = Loc.asStmt())
EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
}
}
}
return PDB.getBugReport()->isValid();
}
/// \brief Adds a sanitized control-flow diagnostic edge to a path.
static void addEdgeToPath(PathPieces &path,
PathDiagnosticLocation &PrevLoc,
PathDiagnosticLocation NewLoc,
const LocationContext *LC) {
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 ObjCForCollectionStmt *FS =
dyn_cast_or_null<ObjCForCollectionStmt>(S))
return FS->getElement();
return S;
}
static const char StrEnteringLoop[] = "Entering loop body";
static const char StrLoopBodyZero[] = "Loop body executed 0 times";
static const char StrLoopRangeEmpty[] =
"Loop body skipped when range is empty";
static const char StrLoopCollectionEmpty[] =
"Loop body skipped when collection is empty";
static bool GenerateAlternateExtensivePathDiagnostic(
PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
LocationContextMap &LCM,
ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
BugReport *report = PDB.getBugReport();
const SourceManager& SM = PDB.getSourceManager();
StackDiagVector CallStack;
InterestingExprs IE;
PathDiagnosticLocation PrevLoc = PD.getLocation();
const ExplodedNode *NextNode = N->getFirstPred();
while (NextNode) {
N = NextNode;
NextNode = N->getFirstPred();
ProgramPoint P = N->getLocation();
do {
// 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 (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
// 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(PD.getActivePath(), PrevLoc,
PathDiagnosticLocation::createBegin(D, SM), CalleeLC);
// Did we visit an entire call?
bool VisitedEntireCall = PD.isWithinCall();
PD.popActivePath();
PathDiagnosticCallPiece *C;
if (VisitedEntireCall) {
PathDiagnosticPiece *P = PD.getActivePath().front().get();
C = cast<PathDiagnosticCallPiece>(P);
} else {
const Decl *Caller = CE->getLocationContext()->getDecl();
C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
// Since we just transferred the path over to the call piece,
// reset the mapping from active to location context.
assert(PD.getActivePath().size() == 1 &&
PD.getActivePath().front().get() == C);
LCM[&PD.getActivePath()] = nullptr;
// Record the location context mapping for the path within
// the call.
assert(LCM[&C->path] == nullptr ||
LCM[&C->path] == CE->getCalleeContext());
LCM[&C->path] = CE->getCalleeContext();
// If this is the first item in the active path, record
// the new mapping from active path to location context.
const LocationContext *&NewLC = LCM[&PD.getActivePath()];
if (!NewLC)
NewLC = N->getLocationContext();
PDB.LC = NewLC;
}
C->setCallee(*CE, SM);
// Update the previous location in the active path.
PrevLoc = C->getLocation();
if (!CallStack.empty()) {
assert(CallStack.back().first == C);
CallStack.pop_back();
}
break;
}
// Query the location context here and the previous location
// as processing CallEnter may change the active path.
PDB.LC = N->getLocationContext();
// Record the mapping from the active path to the location
// context.
assert(!LCM[&PD.getActivePath()] ||
LCM[&PD.getActivePath()] == PDB.LC);
LCM[&PD.getActivePath()] = PDB.LC;
// Have we encountered an exit from a function call?
if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
const Stmt *S = CE->getCalleeContext()->getCallSite();
// Propagate the interesting symbols accordingly.
if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
N->getState().get(), Ex,
N->getLocationContext());
}
// We are descending into a call (backwards). Construct
// a new call piece to contain the path pieces for that call.
auto C = PathDiagnosticCallPiece::construct(N, *CE, SM);
// Record the location context for this call piece.
LCM[&C->path] = CE->getCalleeContext();
// Add the edge to the return site.
addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC);
auto *P = C.get();
PD.getActivePath().push_front(std::move(C));
PrevLoc.invalidate();
// Make the contents of the call the active path for now.
PD.pushActivePath(&P->path);
CallStack.push_back(StackDiagPair(P, N));
break;
}
if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
// For expressions, make sure we propagate the
// interesting symbols correctly.
if (const Expr *Ex = PS->getStmtAs<Expr>())
reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
N->getState().get(), Ex,
N->getLocationContext());
// 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, PDB.LC);
addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
}
break;
}
// Block edges.
if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
// Does this represent entering a call? If so, look at propagating
// interesting symbols across call boundaries.
if (NextNode) {
const LocationContext *CallerCtx = NextNode->getLocationContext();
const LocationContext *CalleeCtx = PDB.LC;
if (CallerCtx != CalleeCtx) {
reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
N->getState().get(),
CalleeCtx, CallerCtx);
}
}
// Are we jumping to the head of a loop? Add a special diagnostic.
if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
PathDiagnosticLocation L(Loop, SM, PDB.LC);
const Stmt *Body = nullptr;
if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
Body = FS->getBody();
else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
Body = WS->getBody();
else if (const ObjCForCollectionStmt *OFS =
dyn_cast<ObjCForCollectionStmt>(Loop)) {
Body = OFS->getBody();
} else if (const CXXForRangeStmt *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(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
PD.getActivePath().push_front(std::move(p));
if (const CompoundStmt *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
addEdgeToPath(PD.getActivePath(), PrevLoc,
PathDiagnosticLocation::createEndBrace(CS, SM),
PDB.LC);
}
}
const CFGBlock *BSrc = BE->getSrc();
ParentMap &PM = PDB.getParentMap();
if (const Stmt *Term = BSrc->getTerminator()) {
// 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, N), Term);
const char *str = nullptr;
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) {
PathDiagnosticLocation L(TermCond ? TermCond : Term, SM, PDB.LC);
auto PE = std::make_shared<PathDiagnosticEventPiece>(L, str);
PE->setPrunable(true);
addEdgeToPath(PD.getActivePath(), PrevLoc,
PE->getLocation(), PDB.LC);
PD.getActivePath().push_front(std::move(PE));
}
} else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) ||
isa<GotoStmt>(Term)) {
PathDiagnosticLocation L(Term, SM, PDB.LC);
addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
}
}
break;
}
} while (0);
if (!NextNode)
continue;
// Add pieces from custom visitors.
for (auto &V : visitors) {
if (auto p = V->VisitNode(N, NextNode, PDB, *report)) {
addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
updateStackPiecesWithMessage(*p, CallStack);
PD.getActivePath().push_front(std::move(p));
}
}
}
// 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 = PDB.LC->getCurrentStackFrame();
const Decl *D = CalleeLC->getDecl();
addEdgeToPath(PD.getActivePath(), PrevLoc,
PathDiagnosticLocation::createBegin(D, SM),
CalleeLC);
return report->isValid();
}
static const Stmt *getLocStmt(PathDiagnosticLocation L) {
if (!L.isValid())
return nullptr;
return L.asStmt();
}
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<ExprWithCleanups>(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 BinaryOperator *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 ConditionalOperator *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 CXXForRangeStmt *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 ForStmt *FS = dyn_cast<ForStmt>(FL))
return FS->getInc() == S || FS->getInit() == S;
if (const CXXForRangeStmt *FRS = dyn_cast<CXXForRangeStmt>(FL))
return FRS->getInc() == S || FRS->getRangeStmt() == S ||
FRS->getLoopVarStmt() || FRS->getRangeInit() == S;
return false;
}
typedef llvm::DenseSet<const PathDiagnosticCallPiece *>
OptimizedCallsSet;
/// 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, SourceManager &SM,
const ParentMap &PM, const LocationContext *LCtx) {
PathPieces::iterator Prev = pieces.end();
for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E;
Prev = I, ++I) {
PathDiagnosticControlFlowPiece *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, SM, PM, LCtx,
/*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 = getLocStmt(Piece->getEndLocation());
// We are looking at an edge. Is the destination within a larger
// expression?
PathDiagnosticLocation DstContext =
getEnclosingStmtLocation(Dst, SM, PM, LCtx, /*allowNested=*/true);
if (!DstContext.isValid() || DstContext.asStmt() == Dst)
break;
// If the source is in the same context, we're already good.
if (std::find(SrcContexts.begin(), SrcContexts.end(), 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 = getLocStmt(PrevPiece->getStartLocation())) {
const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM);
if (PrevSrcParent == getStmtParent(getLocStmt(DstContext), 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));
}
}
}
/// \brief 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) {
auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI)
continue;
const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
if (!s1Start || !s1End)
continue;
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
PathDiagnosticControlFlowPiece *PieceNextI = nullptr;
while (true) {
if (NextI == E)
break;
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 = getLocStmt(PieceNextI->getStartLocation());
const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
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(SourceManager &SM,
SourceRange Range) {
SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()),
SM.getExpansionRange(Range.getEnd()).second);
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(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, SourceManager &SM,
ParentMap &PM) {
for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) {
// Pattern match the current piece and its successor.
PathDiagnosticControlFlowPiece *PieceI =
dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI) {
++I;
continue;
}
const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
PathDiagnosticControlFlowPiece *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 = getLocStmt(PieceNextI->getStartLocation());
const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
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;
}
}
/// \brief Return true if X is contained by Y.
static bool lexicalContains(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,
SourceManager &SM,
ParentMap &PM) {
bool erased = false;
for (PathPieces::iterator I = path.begin(), E = path.end(); I != E;
erased ? I : ++I) {
erased = false;
auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
if (!PieceI)
continue;
const Stmt *start = getLocStmt(PieceI->getStartLocation());
const Stmt *end = getLocStmt(PieceI->getEndLocation());
if (!start || !end)
continue;
const Stmt *endParent = PM.getParent(end);
if (!endParent)
continue;
if (isConditionForTerminator(end, endParent))
continue;
SourceLocation FirstLoc = start->getLocStart();
SourceLocation SecondLoc = end->getLocStart();
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) {
auto *PieceI = dyn_cast<PathDiagnosticEventPiece>(I->get());
if (!PieceI)
continue;
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
return;
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(PathPieces &path, SourceManager &SM,
OptimizedCallsSet &OCS,
LocationContextMap &LCM) {
bool hasChanges = false;
const LocationContext *LC = LCM[&path];
assert(LC);
ParentMap &PM = LC->getParentMap();
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(CallI->path, SM, OCS, LCM)) {}
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 = getLocStmt(PieceI->getStartLocation());
const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
const Stmt *level1 = getStmtParent(s1Start, PM);
const Stmt *level2 = getStmtParent(s1End, PM);
PathPieces::iterator NextI = I; ++NextI;
if (NextI == E)
break;
auto *PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
if (!PieceNextI) {
++I;
continue;
}
const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
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 ObjCForCollectionStmt *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, SM, PM, LC);
// Remove "cyclical" edges that include one or more context edges.
removeContextCycles(path, SM, PM);
// 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(PathPieces &Path,
LocationContextMap &LCM,
SourceManager &SM) {
const auto *FirstEdge =
dyn_cast<PathDiagnosticControlFlowPiece>(Path.front().get());
if (!FirstEdge)
return;
const Decl *D = LCM[&Path]->getDecl();
PathDiagnosticLocation EntryLoc = PathDiagnosticLocation::createBegin(D, SM);
if (FirstEdge->getStartLocation() != EntryLoc)
return;
Path.pop_front();
}
//===----------------------------------------------------------------------===//
// Methods for BugType and subclasses.
//===----------------------------------------------------------------------===//
void BugType::anchor() { }
void BugType::FlushReports(BugReporter &BR) {}
void BuiltinBug::anchor() {}
//===----------------------------------------------------------------------===//
// Methods for BugReport and subclasses.
//===----------------------------------------------------------------------===//
void BugReport::NodeResolver::anchor() {}
void BugReport::addVisitor(std::unique_ptr<BugReporterVisitor> visitor) {
if (!visitor)
return;
llvm::FoldingSetNodeID ID;
visitor->Profile(ID);
void *InsertPos;
if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos))
return;
CallbacksSet.InsertNode(visitor.get(), InsertPos);
Callbacks.push_back(std::move(visitor));
++ConfigurationChangeToken;
}
BugReport::~BugReport() {
while (!interestingSymbols.empty()) {
popInterestingSymbolsAndRegions();
}
}
const Decl *BugReport::getDeclWithIssue() const {
if (DeclWithIssue)
return DeclWithIssue;
const ExplodedNode *N = getErrorNode();
if (!N)
return nullptr;
const LocationContext *LC = N->getLocationContext();
return LC->getCurrentStackFrame()->getDecl();
}
void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
hash.AddPointer(&BT);
hash.AddString(Description);
PathDiagnosticLocation UL = getUniqueingLocation();
if (UL.isValid()) {
UL.Profile(hash);
} else if (Location.isValid()) {
Location.Profile(hash);
} else {
assert(ErrorNode);
hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode));
}
for (SourceRange range : Ranges) {
if (!range.isValid())
continue;
hash.AddInteger(range.getBegin().getRawEncoding());
hash.AddInteger(range.getEnd().getRawEncoding());
}
}
void BugReport::markInteresting(SymbolRef sym) {
if (!sym)
return;
// If the symbol wasn't already in our set, note a configuration change.
if (getInterestingSymbols().insert(sym).second)
++ConfigurationChangeToken;
if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym))
getInterestingRegions().insert(meta->getRegion());
}
void BugReport::markInteresting(const MemRegion *R) {
if (!R)
return;
// If the base region wasn't already in our set, note a configuration change.
R = R->getBaseRegion();
if (getInterestingRegions().insert(R).second)
++ConfigurationChangeToken;
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
getInterestingSymbols().insert(SR->getSymbol());
}
void BugReport::markInteresting(SVal V) {
markInteresting(V.getAsRegion());
markInteresting(V.getAsSymbol());
}
void BugReport::markInteresting(const LocationContext *LC) {
if (!LC)
return;
InterestingLocationContexts.insert(LC);
}
bool BugReport::isInteresting(SVal V) {
return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol());
}
bool BugReport::isInteresting(SymbolRef sym) {
if (!sym)
return false;
// We don't currently consider metadata symbols to be interesting
// even if we know their region is interesting. Is that correct behavior?
return getInterestingSymbols().count(sym);
}
bool BugReport::isInteresting(const MemRegion *R) {
if (!R)
return false;
R = R->getBaseRegion();
bool b = getInterestingRegions().count(R);
if (b)
return true;
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
return getInterestingSymbols().count(SR->getSymbol());
return false;
}
bool BugReport::isInteresting(const LocationContext *LC) {
if (!LC)
return false;
return InterestingLocationContexts.count(LC);
}
void BugReport::lazyInitializeInterestingSets() {
if (interestingSymbols.empty()) {
interestingSymbols.push_back(new Symbols());
interestingRegions.push_back(new Regions());
}
}
BugReport::Symbols &BugReport::getInterestingSymbols() {
lazyInitializeInterestingSets();
return *interestingSymbols.back();
}
BugReport::Regions &BugReport::getInterestingRegions() {
lazyInitializeInterestingSets();
return *interestingRegions.back();
}
void BugReport::pushInterestingSymbolsAndRegions() {
interestingSymbols.push_back(new Symbols(getInterestingSymbols()));
interestingRegions.push_back(new Regions(getInterestingRegions()));
}
void BugReport::popInterestingSymbolsAndRegions() {
delete interestingSymbols.pop_back_val();
delete interestingRegions.pop_back_val();
}
const Stmt *BugReport::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 = GetPreviousStmt(ErrorNode);
}
if (!S)
S = PathDiagnosticLocation::getStmt(ErrorNode);
return S;
}
llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() {
// If no custom ranges, add the range of the statement corresponding to
// the error node.
if (Ranges.empty()) {
if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
addRange(E->getSourceRange());
else
return llvm::make_range(ranges_iterator(), ranges_iterator());
}
// User-specified absence of range info.
if (Ranges.size() == 1 && !Ranges.begin()->isValid())
return llvm::make_range(ranges_iterator(), ranges_iterator());
return llvm::make_range(Ranges.begin(), Ranges.end());
}
PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const {
if (ErrorNode) {
assert(!Location.isValid() &&
"Either Location or ErrorNode should be specified but not both.");
return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM);
}
assert(Location.isValid());
return Location;
}
//===----------------------------------------------------------------------===//
// Methods for BugReporter and subclasses.
//===----------------------------------------------------------------------===//
BugReportEquivClass::~BugReportEquivClass() { }
GRBugReporter::~GRBugReporter() { }
BugReporterData::~BugReporterData() {}
ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
ProgramStateManager&
GRBugReporter::getStateManager() { return Eng.getStateManager(); }
BugReporter::~BugReporter() {
FlushReports();
// Free the bug reports we are tracking.
typedef std::vector<BugReportEquivClass *> ContTy;
for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end();
I != E; ++I) {
delete *I;
}
}
void BugReporter::FlushReports() {
if (BugTypes.isEmpty())
return;
// First flush the warnings for each BugType. This may end up creating new
// warnings and new BugTypes.
// FIXME: Only NSErrorChecker needs BugType's FlushReports.
// Turn NSErrorChecker into a proper checker and remove this.
SmallVector<const BugType *, 16> bugTypes(BugTypes.begin(), BugTypes.end());
for (SmallVectorImpl<const BugType *>::iterator
I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
const_cast<BugType*>(*I)->FlushReports(*this);
// We need to flush reports in deterministic order to ensure the order
// of the reports is consistent between runs.
typedef std::vector<BugReportEquivClass *> ContVecTy;
for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end();
EI != EE; ++EI){
BugReportEquivClass& EQ = **EI;
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);
// Remove all references to the BugType objects.
BugTypes = F.getEmptySet();
}
//===----------------------------------------------------------------------===//
// PathDiagnostics generation.
//===----------------------------------------------------------------------===//
namespace {
/// A wrapper around a report graph, which contains only a single path, and its
/// node maps.