void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
BugReporter &B,
ExprEngine &Eng) const {
CFGBlocksSet reachable, visited;
if (Eng.hasWorkRemaining())
return;
const Decl *D = nullptr;
CFG *C = nullptr;
ParentMap *PM = nullptr;
const LocationContext *LC = nullptr;
// Iterate over ExplodedGraph
for (ExplodedGraph::node_iterator I = G.nodes_begin(), E = G.nodes_end();
I != E; ++I) {
const ProgramPoint &P = I->getLocation();
LC = P.getLocationContext();
if (!LC->inTopFrame())
continue;
if (!D)
D = LC->getAnalysisDeclContext()->getDecl();
// Save the CFG if we don't have it already
if (!C)
C = LC->getAnalysisDeclContext()->getUnoptimizedCFG();
if (!PM)
PM = &LC->getParentMap();
if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
const CFGBlock *CB = BE->getBlock();
reachable.insert(CB->getBlockID());
}
}
// Bail out if we didn't get the CFG or the ParentMap.
if (!D || !C || !PM)
return;
// Don't do anything for template instantiations. Proving that code
// in a template instantiation is unreachable means proving that it is
// unreachable in all instantiations.
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
if (FD->isTemplateInstantiation())
return;
// Find CFGBlocks that were not covered by any node
for (CFG::const_iterator I = C->begin(), E = C->end(); I != E; ++I) {
const CFGBlock *CB = *I;
// Check if the block is unreachable
if (reachable.count(CB->getBlockID()))
continue;
// Check if the block is empty (an artificial block)
if (isEmptyCFGBlock(CB))
continue;
// Find the entry points for this block
if (!visited.count(CB->getBlockID()))
FindUnreachableEntryPoints(CB, reachable, visited);
// This block may have been pruned; check if we still want to report it
if (reachable.count(CB->getBlockID()))
continue;
// Check for false positives
if (isInvalidPath(CB, *PM))
continue;
// It is good practice to always have a "default" label in a "switch", even
// if we should never get there. It can be used to detect errors, for
// instance. Unreachable code directly under a "default" label is therefore
// likely to be a false positive.
if (const Stmt *label = CB->getLabel())
if (label->getStmtClass() == Stmt::DefaultStmtClass)
continue;
// Special case for __builtin_unreachable.
// FIXME: This should be extended to include other unreachable markers,
// such as llvm_unreachable.
if (!CB->empty()) {
bool foundUnreachable = false;
for (CFGBlock::const_iterator ci = CB->begin(), ce = CB->end();
ci != ce; ++ci) {
if (Optional<CFGStmt> S = (*ci).getAs<CFGStmt>())
if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
if (CE->getBuiltinCallee() == Builtin::BI__builtin_unreachable ||
CE->isBuiltinAssumeFalse(Eng.getContext())) {
foundUnreachable = true;
break;
}
}
}
if (foundUnreachable)
continue;
}
// We found a block that wasn't covered - find the statement to report
SourceRange SR;
PathDiagnosticLocation DL;
SourceLocation SL;
if (const Stmt *S = getUnreachableStmt(CB)) {
// In macros, 'do {...} while (0)' is often used. Don't warn about the
// condition 0 when it is unreachable.
if (S->getBeginLoc().isMacroID())
if (const auto *I = dyn_cast<IntegerLiteral>(S))
if (I->getValue() == 0ULL)
if (const Stmt *Parent = PM->getParent(S))
if (isa<DoStmt>(Parent))
continue;
SR = S->getSourceRange();
DL = PathDiagnosticLocation::createBegin(S, B.getSourceManager(), LC);
SL = DL.asLocation();
if (SR.isInvalid() || !SL.isValid())
continue;
}
else
continue;
// Check if the SourceLocation is in a system header
const SourceManager &SM = B.getSourceManager();
if (SM.isInSystemHeader(SL) || SM.isInExternCSystemHeader(SL))
continue;
B.EmitBasicReport(D, this, "Unreachable code", "Dead code",
"This statement is never executed", DL, SR);
}
}
void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
BugReporter &B,
ExprEngine &Eng) const {
const CFG *C = 0;
const SourceManager &SM = B.getSourceManager();
llvm::SmallPtrSet<const CFGBlock*, 256> reachable;
// Root node should have the location context of the top most function.
const ExplodedNode *GraphRoot = *G.roots_begin();
const LocationContext *LC = GraphRoot->getLocation().getLocationContext();
const Decl *D = LC->getDecl();
// Iterate over the exploded graph.
for (ExplodedGraph::node_iterator I = G.nodes_begin();
I != G.nodes_end(); ++I) {
const ProgramPoint &P = I->getLocation();
// Only check the coverage in the top level function (optimization).
if (D != P.getLocationContext()->getDecl())
continue;
if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
const CFGBlock *CB = BE->getBlock();
reachable.insert(CB);
}
}
// Get the CFG and the Decl of this block.
C = LC->getCFG();
unsigned total = 0, unreachable = 0;
// Find CFGBlocks that were not covered by any node
for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
const CFGBlock *CB = *I;
++total;
// Check if the block is unreachable
if (!reachable.count(CB)) {
++unreachable;
}
}
// We never 'reach' the entry block, so correct the unreachable count
unreachable--;
// There is no BlockEntrance corresponding to the exit block as well, so
// assume it is reached as well.
unreachable--;
// Generate the warning string
SmallString<128> buf;
llvm::raw_svector_ostream output(buf);
PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
if (!Loc.isValid())
return;
if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
const NamedDecl *ND = cast<NamedDecl>(D);
output << *ND;
}
else if (isa<BlockDecl>(D)) {
output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
}
NumBlocksUnreachable += unreachable;
NumBlocks += total;
std::string NameOfRootFunction = output.str();
output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
<< unreachable << " | Exhausted Block: "
<< (Eng.wasBlocksExhausted() ? "yes" : "no")
<< " | Empty WorkList: "
<< (Eng.hasEmptyWorkList() ? "yes" : "no");
B.EmitBasicReport(D, "Analyzer Statistics", "Internal Statistics",
output.str(), PathDiagnosticLocation(D, SM));
// Emit warning for each block we bailed out on.
typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
const CoreEngine &CE = Eng.getCoreEngine();
for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
E = CE.blocks_exhausted_end(); I != E; ++I) {
const BlockEdge &BE = I->first;
const CFGBlock *Exit = BE.getDst();
const CFGElement &CE = Exit->front();
if (const CFGStmt *CS = dyn_cast<CFGStmt>(&CE)) {
SmallString<128> bufI;
llvm::raw_svector_ostream outputI(bufI);
outputI << "(" << NameOfRootFunction << ")" <<
": The analyzer generated a sink at this point";
B.EmitBasicReport(D, "Sink Point", "Internal Statistics", outputI.str(),
PathDiagnosticLocation::createBegin(CS->getStmt(),
SM, LC));
}
}
}
void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
BugReporter &B,
ExprEngine &Eng) const {
CFGBlocksSet reachable, visited;
if (Eng.hasWorkRemaining())
return;
CFG *C = 0;
ParentMap *PM = 0;
// Iterate over ExplodedGraph
for (ExplodedGraph::node_iterator I = G.nodes_begin(), E = G.nodes_end();
I != E; ++I) {
const ProgramPoint &P = I->getLocation();
const LocationContext *LC = P.getLocationContext();
// Save the CFG if we don't have it already
if (!C)
C = LC->getAnalysisContext()->getUnoptimizedCFG();
if (!PM)
PM = &LC->getParentMap();
if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
const CFGBlock *CB = BE->getBlock();
reachable.insert(CB->getBlockID());
}
}
// Bail out if we didn't get the CFG or the ParentMap.
if (!C || !PM)
return;
ASTContext &Ctx = B.getContext();
// Find CFGBlocks that were not covered by any node
for (CFG::const_iterator I = C->begin(), E = C->end(); I != E; ++I) {
const CFGBlock *CB = *I;
// Check if the block is unreachable
if (reachable.count(CB->getBlockID()))
continue;
// Check if the block is empty (an artificial block)
if (isEmptyCFGBlock(CB))
continue;
// Find the entry points for this block
if (!visited.count(CB->getBlockID()))
FindUnreachableEntryPoints(CB, reachable, visited);
// This block may have been pruned; check if we still want to report it
if (reachable.count(CB->getBlockID()))
continue;
// Check for false positives
if (CB->size() > 0 && isInvalidPath(CB, *PM))
continue;
// Special case for __builtin_unreachable.
// FIXME: This should be extended to include other unreachable markers,
// such as llvm_unreachable.
if (!CB->empty()) {
CFGElement First = CB->front();
if (const CFGStmt *S = First.getAs<CFGStmt>()) {
if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
if (CE->isBuiltinCall(Ctx) == Builtin::BI__builtin_unreachable)
continue;
}
}
}
// We found a block that wasn't covered - find the statement to report
SourceRange SR;
SourceLocation SL;
if (const Stmt *S = getUnreachableStmt(CB)) {
SR = S->getSourceRange();
SL = S->getLocStart();
if (SR.isInvalid() || SL.isInvalid())
continue;
}
else
continue;
// Check if the SourceLocation is in a system header
const SourceManager &SM = B.getSourceManager();
if (SM.isInSystemHeader(SL) || SM.isInExternCSystemHeader(SL))
continue;
B.EmitBasicReport("Unreachable code", "Dead code", "This statement is never"
" executed", SL, SR);
}
}
void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
BugReporter &B,
ExprEngine &Eng) const {
const CFG *C = 0;
const Decl *D = 0;
const LocationContext *LC = 0;
const SourceManager &SM = B.getSourceManager();
llvm::SmallPtrSet<const CFGBlock*, 256> reachable;
// Iterate over explodedgraph
for (ExplodedGraph::node_iterator I = G.nodes_begin();
I != G.nodes_end(); ++I) {
const ProgramPoint &P = I->getLocation();
// Save the LocationContext if we don't have it already
if (!LC)
LC = P.getLocationContext();
if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
const CFGBlock *CB = BE->getBlock();
reachable.insert(CB);
}
}
// Get the CFG and the Decl of this block
C = LC->getCFG();
D = LC->getAnalysisContext()->getDecl();
unsigned total = 0, unreachable = 0;
// Find CFGBlocks that were not covered by any node
for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
const CFGBlock *CB = *I;
++total;
// Check if the block is unreachable
if (!reachable.count(CB)) {
++unreachable;
}
}
// We never 'reach' the entry block, so correct the unreachable count
unreachable--;
// Generate the warning string
llvm::SmallString<128> buf;
llvm::raw_svector_ostream output(buf);
PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
if (Loc.isValid()) {
output << Loc.getFilename() << " : ";
if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
const NamedDecl *ND = cast<NamedDecl>(D);
output << ND;
}
else if (isa<BlockDecl>(D)) {
output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
}
}
output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
<< unreachable << " | Exhausted Block: "
<< (Eng.wasBlocksExhausted() ? "yes" : "no")
<< " | Empty WorkList: "
<< (Eng.hasEmptyWorkList() ? "yes" : "no");
B.EmitBasicReport("Analyzer Statistics", "Internal Statistics", output.str(),
PathDiagnosticLocation(D, SM));
// Emit warning for each block we bailed out on
typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
const CoreEngine &CE = Eng.getCoreEngine();
for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
E = CE.blocks_exhausted_end(); I != E; ++I) {
const BlockEdge &BE = I->first;
const CFGBlock *Exit = BE.getDst();
const CFGElement &CE = Exit->front();
if (const CFGStmt *CS = dyn_cast<CFGStmt>(&CE))
B.EmitBasicReport("Bailout Point", "Internal Statistics", "The analyzer "
"stopped analyzing at this point",
PathDiagnosticLocation::createBegin(CS->getStmt(), SM, LC));
}
}