diff options
Diffstat (limited to 'contrib/llvm/tools/clang/lib/Analysis')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/AnalysisContext.cpp | 325 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/CFG.cpp | 2380 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/CMakeLists.txt | 12 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/LiveVariables.cpp | 382 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/Makefile | 21 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/PrintfFormatString.cpp | 584 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/ReachableCode.cpp | 278 | ||||
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/UninitializedValues.cpp | 314 |
8 files changed, 4296 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Analysis/AnalysisContext.cpp b/contrib/llvm/tools/clang/lib/Analysis/AnalysisContext.cpp new file mode 100644 index 0000000..06d8aec --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/AnalysisContext.cpp @@ -0,0 +1,325 @@ +//== AnalysisContext.cpp - Analysis context for Path Sens analysis -*- 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 AnalysisContext, a class that manages the analysis context +// data for path sensitive analysis. +// +//===----------------------------------------------------------------------===// + +#include "clang/AST/Decl.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/DeclTemplate.h" +#include "clang/AST/ParentMap.h" +#include "clang/AST/StmtVisitor.h" +#include "clang/Analysis/Analyses/LiveVariables.h" +#include "clang/Analysis/AnalysisContext.h" +#include "clang/Analysis/CFG.h" +#include "clang/Analysis/Support/BumpVector.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/Support/ErrorHandling.h" + +using namespace clang; + +void AnalysisContextManager::clear() { + for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I) + delete I->second; + Contexts.clear(); +} + +Stmt *AnalysisContext::getBody() { + if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) + return FD->getBody(); + else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) + return MD->getBody(); + else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) + return BD->getBody(); + else if (const FunctionTemplateDecl *FunTmpl + = dyn_cast_or_null<FunctionTemplateDecl>(D)) + return FunTmpl->getTemplatedDecl()->getBody(); + + llvm_unreachable("unknown code decl"); +} + +const ImplicitParamDecl *AnalysisContext::getSelfDecl() const { + if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) + return MD->getSelfDecl(); + + return NULL; +} + +CFG *AnalysisContext::getCFG() { + if (!builtCFG) { + cfg = CFG::buildCFG(D, getBody(), &D->getASTContext(), AddEHEdges); + // Even when the cfg is not successfully built, we don't + // want to try building it again. + builtCFG = true; + } + return cfg; +} + +ParentMap &AnalysisContext::getParentMap() { + if (!PM) + PM = new ParentMap(getBody()); + return *PM; +} + +LiveVariables *AnalysisContext::getLiveVariables() { + if (!liveness) { + CFG *c = getCFG(); + if (!c) + return 0; + + liveness = new LiveVariables(*this); + liveness->runOnCFG(*c); + liveness->runOnAllBlocks(*c, 0, true); + } + + return liveness; +} + +AnalysisContext *AnalysisContextManager::getContext(const Decl *D) { + AnalysisContext *&AC = Contexts[D]; + if (!AC) + AC = new AnalysisContext(D); + + return AC; +} + +//===----------------------------------------------------------------------===// +// FoldingSet profiling. +//===----------------------------------------------------------------------===// + +void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID, + ContextKind ck, + AnalysisContext *ctx, + const LocationContext *parent, + const void* data) { + ID.AddInteger(ck); + ID.AddPointer(ctx); + ID.AddPointer(parent); + ID.AddPointer(data); +} + +void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) { + Profile(ID, getAnalysisContext(), getParent(), CallSite, Block, Index); +} + +void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) { + Profile(ID, getAnalysisContext(), getParent(), Enter); +} + +void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) { + Profile(ID, getAnalysisContext(), getParent(), BD); +} + +//===----------------------------------------------------------------------===// +// LocationContext creation. +//===----------------------------------------------------------------------===// + +template <typename LOC, typename DATA> +const LOC* +LocationContextManager::getLocationContext(AnalysisContext *ctx, + const LocationContext *parent, + const DATA *d) { + llvm::FoldingSetNodeID ID; + LOC::Profile(ID, ctx, parent, d); + void *InsertPos; + + LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos)); + + if (!L) { + L = new LOC(ctx, parent, d); + Contexts.InsertNode(L, InsertPos); + } + return L; +} + +const StackFrameContext* +LocationContextManager::getStackFrame(AnalysisContext *ctx, + const LocationContext *parent, + const Stmt *s, const CFGBlock *blk, + unsigned idx) { + llvm::FoldingSetNodeID ID; + StackFrameContext::Profile(ID, ctx, parent, s, blk, idx); + void *InsertPos; + StackFrameContext *L = + cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos)); + if (!L) { + L = new StackFrameContext(ctx, parent, s, blk, idx); + Contexts.InsertNode(L, InsertPos); + } + return L; +} + +const ScopeContext * +LocationContextManager::getScope(AnalysisContext *ctx, + const LocationContext *parent, + const Stmt *s) { + return getLocationContext<ScopeContext, Stmt>(ctx, parent, s); +} + +//===----------------------------------------------------------------------===// +// LocationContext methods. +//===----------------------------------------------------------------------===// + +const StackFrameContext *LocationContext::getCurrentStackFrame() const { + const LocationContext *LC = this; + while (LC) { + if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) + return SFC; + LC = LC->getParent(); + } + return NULL; +} + +const StackFrameContext * +LocationContext::getStackFrameForDeclContext(const DeclContext *DC) const { + const LocationContext *LC = this; + while (LC) { + if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) { + if (cast<DeclContext>(SFC->getDecl()) == DC) + return SFC; + } + LC = LC->getParent(); + } + return NULL; +} + +bool LocationContext::isParentOf(const LocationContext *LC) const { + do { + const LocationContext *Parent = LC->getParent(); + if (Parent == this) + return true; + else + LC = Parent; + } while (LC); + + return false; +} + +//===----------------------------------------------------------------------===// +// Lazily generated map to query the external variables referenced by a Block. +//===----------------------------------------------------------------------===// + +namespace { +class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{ + BumpVector<const VarDecl*> &BEVals; + BumpVectorContext &BC; + llvm::DenseMap<const VarDecl*, unsigned> Visited; + llvm::SmallSet<const DeclContext*, 4> IgnoredContexts; +public: + FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals, + BumpVectorContext &bc) + : BEVals(bevals), BC(bc) {} + + bool IsTrackedDecl(const VarDecl *VD) { + const DeclContext *DC = VD->getDeclContext(); + return IgnoredContexts.count(DC) == 0; + } + + void VisitStmt(Stmt *S) { + for (Stmt::child_iterator I = S->child_begin(), E = S->child_end();I!=E;++I) + if (Stmt *child = *I) + Visit(child); + } + + void VisitDeclRefExpr(const DeclRefExpr *DR) { + // Non-local variables are also directly modified. + if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) + if (!VD->hasLocalStorage()) { + unsigned &flag = Visited[VD]; + if (!flag) { + flag = 1; + BEVals.push_back(VD, BC); + } + } + } + + void VisitBlockDeclRefExpr(BlockDeclRefExpr *DR) { + if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { + unsigned &flag = Visited[VD]; + if (!flag) { + flag = 1; + if (IsTrackedDecl(VD)) + BEVals.push_back(VD, BC); + } + } + } + + void VisitBlockExpr(BlockExpr *BR) { + // Blocks containing blocks can transitively capture more variables. + IgnoredContexts.insert(BR->getBlockDecl()); + Visit(BR->getBlockDecl()->getBody()); + } +}; +} // end anonymous namespace + +typedef BumpVector<const VarDecl*> DeclVec; + +static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD, + void *&Vec, + llvm::BumpPtrAllocator &A) { + if (Vec) + return (DeclVec*) Vec; + + BumpVectorContext BC(A); + DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>(); + new (BV) DeclVec(BC, 10); + + // Find the referenced variables. + FindBlockDeclRefExprsVals F(*BV, BC); + F.Visit(BD->getBody()); + + Vec = BV; + return BV; +} + +std::pair<AnalysisContext::referenced_decls_iterator, + AnalysisContext::referenced_decls_iterator> +AnalysisContext::getReferencedBlockVars(const BlockDecl *BD) { + if (!ReferencedBlockVars) + ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>(); + + DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A); + return std::make_pair(V->begin(), V->end()); +} + +//===----------------------------------------------------------------------===// +// Cleanup. +//===----------------------------------------------------------------------===// + +AnalysisContext::~AnalysisContext() { + delete cfg; + delete liveness; + delete PM; + delete ReferencedBlockVars; +} + +AnalysisContextManager::~AnalysisContextManager() { + for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I) + delete I->second; +} + +LocationContext::~LocationContext() {} + +LocationContextManager::~LocationContextManager() { + clear(); +} + +void LocationContextManager::clear() { + for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(), + E = Contexts.end(); I != E; ) { + LocationContext *LC = &*I; + ++I; + delete LC; + } + + Contexts.clear(); +} + diff --git a/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp b/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp new file mode 100644 index 0000000..6f2cb41 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp @@ -0,0 +1,2380 @@ +//===--- CFG.cpp - Classes for representing and building CFGs----*- 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 the CFG and CFGBuilder classes for representing and +// building Control-Flow Graphs (CFGs) from ASTs. +// +//===----------------------------------------------------------------------===// + +#include "clang/Analysis/Support/SaveAndRestore.h" +#include "clang/Analysis/CFG.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtVisitor.h" +#include "clang/AST/PrettyPrinter.h" +#include "llvm/Support/GraphWriter.h" +#include "llvm/Support/Allocator.h" +#include "llvm/Support/Format.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/OwningPtr.h" + +using namespace clang; + +namespace { + +static SourceLocation GetEndLoc(Decl* D) { + if (VarDecl* VD = dyn_cast<VarDecl>(D)) + if (Expr* Ex = VD->getInit()) + return Ex->getSourceRange().getEnd(); + + return D->getLocation(); +} + +class AddStmtChoice { +public: + enum Kind { NotAlwaysAdd = 0, + AlwaysAdd = 1, + AsLValueNotAlwaysAdd = 2, + AlwaysAddAsLValue = 3 }; + + AddStmtChoice(Kind kind) : k(kind) {} + + bool alwaysAdd() const { return (unsigned)k & 0x1; } + bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } + +private: + Kind k; +}; + +/// CFGBuilder - This class implements CFG construction from an AST. +/// The builder is stateful: an instance of the builder should be used to only +/// construct a single CFG. +/// +/// Example usage: +/// +/// CFGBuilder builder; +/// CFG* cfg = builder.BuildAST(stmt1); +/// +/// CFG construction is done via a recursive walk of an AST. We actually parse +/// the AST in reverse order so that the successor of a basic block is +/// constructed prior to its predecessor. This allows us to nicely capture +/// implicit fall-throughs without extra basic blocks. +/// +class CFGBuilder { + ASTContext *Context; + llvm::OwningPtr<CFG> cfg; + + CFGBlock* Block; + CFGBlock* Succ; + CFGBlock* ContinueTargetBlock; + CFGBlock* BreakTargetBlock; + CFGBlock* SwitchTerminatedBlock; + CFGBlock* DefaultCaseBlock; + CFGBlock* TryTerminatedBlock; + + // LabelMap records the mapping from Label expressions to their blocks. + typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; + LabelMapTy LabelMap; + + // A list of blocks that end with a "goto" that must be backpatched to their + // resolved targets upon completion of CFG construction. + typedef std::vector<CFGBlock*> BackpatchBlocksTy; + BackpatchBlocksTy BackpatchBlocks; + + // A list of labels whose address has been taken (for indirect gotos). + typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; + LabelSetTy AddressTakenLabels; + +public: + explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG + Block(NULL), Succ(NULL), + ContinueTargetBlock(NULL), BreakTargetBlock(NULL), + SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), + TryTerminatedBlock(NULL) {} + + // buildCFG - Used by external clients to construct the CFG. + CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, bool AddEHEdges, + bool AddScopes); + +private: + // Visitors to walk an AST and construct the CFG. + CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); + CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); + CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); + CFGBlock *VisitBreakStmt(BreakStmt *B); + CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); + CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); + CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); + CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); + CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); + CFGBlock *VisitCaseStmt(CaseStmt *C); + CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); + CFGBlock *VisitCompoundStmt(CompoundStmt *C); + CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); + CFGBlock *VisitContinueStmt(ContinueStmt *C); + CFGBlock *VisitDeclStmt(DeclStmt *DS); + CFGBlock *VisitDeclSubExpr(Decl* D); + CFGBlock *VisitDefaultStmt(DefaultStmt *D); + CFGBlock *VisitDoStmt(DoStmt *D); + CFGBlock *VisitForStmt(ForStmt *F); + CFGBlock *VisitGotoStmt(GotoStmt* G); + CFGBlock *VisitIfStmt(IfStmt *I); + CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); + CFGBlock *VisitLabelStmt(LabelStmt *L); + CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); + CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); + CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); + CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); + CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); + CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); + CFGBlock *VisitReturnStmt(ReturnStmt* R); + CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); + CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); + CFGBlock *VisitSwitchStmt(SwitchStmt *S); + CFGBlock *VisitWhileStmt(WhileStmt *W); + + CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); + CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); + CFGBlock *VisitChildren(Stmt* S); + + // NYS == Not Yet Supported + CFGBlock* NYS() { + badCFG = true; + return Block; + } + + CFGBlock *StartScope(Stmt *S, CFGBlock *B) { + if (!AddScopes) + return B; + + if (B == 0) + B = createBlock(); + B->StartScope(S, cfg->getBumpVectorContext()); + return B; + } + + void EndScope(Stmt *S) { + if (!AddScopes) + return; + + if (Block == 0) + Block = createBlock(); + Block->EndScope(S, cfg->getBumpVectorContext()); + } + + void autoCreateBlock() { if (!Block) Block = createBlock(); } + CFGBlock *createBlock(bool add_successor = true); + bool FinishBlock(CFGBlock* B); + CFGBlock *addStmt(Stmt *S, AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { + return Visit(S, asc); + } + + void AppendStmt(CFGBlock *B, Stmt *S, + AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { + B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); + } + + void AddSuccessor(CFGBlock *B, CFGBlock *S) { + B->addSuccessor(S, cfg->getBumpVectorContext()); + } + + /// TryResult - a class representing a variant over the values + /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, + /// and is used by the CFGBuilder to decide if a branch condition + /// can be decided up front during CFG construction. + class TryResult { + int X; + public: + TryResult(bool b) : X(b ? 1 : 0) {} + TryResult() : X(-1) {} + + bool isTrue() const { return X == 1; } + bool isFalse() const { return X == 0; } + bool isKnown() const { return X >= 0; } + void negate() { + assert(isKnown()); + X ^= 0x1; + } + }; + + /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 + /// if we can evaluate to a known value, otherwise return -1. + TryResult TryEvaluateBool(Expr *S) { + Expr::EvalResult Result; + if (!S->isTypeDependent() && !S->isValueDependent() && + S->Evaluate(Result, *Context) && Result.Val.isInt()) + return Result.Val.getInt().getBoolValue(); + + return TryResult(); + } + + bool badCFG; + + // True iff EH edges on CallExprs should be added to the CFG. + bool AddEHEdges; + + // True iff scope start and scope end notes should be added to the CFG. + bool AddScopes; +}; + +// FIXME: Add support for dependent-sized array types in C++? +// Does it even make sense to build a CFG for an uninstantiated template? +static VariableArrayType* FindVA(Type* t) { + while (ArrayType* vt = dyn_cast<ArrayType>(t)) { + if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) + if (vat->getSizeExpr()) + return vat; + + t = vt->getElementType().getTypePtr(); + } + + return 0; +} + +/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an +/// arbitrary statement. Examples include a single expression or a function +/// body (compound statement). The ownership of the returned CFG is +/// transferred to the caller. If CFG construction fails, this method returns +/// NULL. +CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, + bool addehedges, bool AddScopes) { + AddEHEdges = addehedges; + Context = C; + assert(cfg.get()); + if (!Statement) + return NULL; + + this->AddScopes = AddScopes; + badCFG = false; + + // Create an empty block that will serve as the exit block for the CFG. Since + // this is the first block added to the CFG, it will be implicitly registered + // as the exit block. + Succ = createBlock(); + assert(Succ == &cfg->getExit()); + Block = NULL; // the EXIT block is empty. Create all other blocks lazily. + + // Visit the statements and create the CFG. + CFGBlock* B = addStmt(Statement); + + if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { + // FIXME: Add code for base initializers and member initializers. + (void)CD; + } + if (!B) + B = Succ; + + if (B) { + // Finalize the last constructed block. This usually involves reversing the + // order of the statements in the block. + if (Block) FinishBlock(B); + + // Backpatch the gotos whose label -> block mappings we didn't know when we + // encountered them. + for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), + E = BackpatchBlocks.end(); I != E; ++I ) { + + CFGBlock* B = *I; + GotoStmt* G = cast<GotoStmt>(B->getTerminator()); + LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); + + // If there is no target for the goto, then we are looking at an + // incomplete AST. Handle this by not registering a successor. + if (LI == LabelMap.end()) continue; + + AddSuccessor(B, LI->second); + } + + // Add successors to the Indirect Goto Dispatch block (if we have one). + if (CFGBlock* B = cfg->getIndirectGotoBlock()) + for (LabelSetTy::iterator I = AddressTakenLabels.begin(), + E = AddressTakenLabels.end(); I != E; ++I ) { + + // Lookup the target block. + LabelMapTy::iterator LI = LabelMap.find(*I); + + // If there is no target block that contains label, then we are looking + // at an incomplete AST. Handle this by not registering a successor. + if (LI == LabelMap.end()) continue; + + AddSuccessor(B, LI->second); + } + + Succ = B; + } + + // Create an empty entry block that has no predecessors. + cfg->setEntry(createBlock()); + + return badCFG ? NULL : cfg.take(); +} + +/// createBlock - Used to lazily create blocks that are connected +/// to the current (global) succcessor. +CFGBlock* CFGBuilder::createBlock(bool add_successor) { + CFGBlock* B = cfg->createBlock(); + if (add_successor && Succ) + AddSuccessor(B, Succ); + return B; +} + +/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. +bool CFGBuilder::FinishBlock(CFGBlock* B) { + if (badCFG) + return false; + + assert(B); + return true; +} + +/// Visit - Walk the subtree of a statement and add extra +/// blocks for ternary operators, &&, and ||. We also process "," and +/// DeclStmts (which may contain nested control-flow). +CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { +tryAgain: + if (!S) { + badCFG = true; + return 0; + } + switch (S->getStmtClass()) { + default: + return VisitStmt(S, asc); + + case Stmt::AddrLabelExprClass: + return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); + + case Stmt::BinaryOperatorClass: + return VisitBinaryOperator(cast<BinaryOperator>(S), asc); + + case Stmt::BlockExprClass: + return VisitBlockExpr(cast<BlockExpr>(S), asc); + + case Stmt::BreakStmtClass: + return VisitBreakStmt(cast<BreakStmt>(S)); + + case Stmt::CallExprClass: + return VisitCallExpr(cast<CallExpr>(S), asc); + + case Stmt::CaseStmtClass: + return VisitCaseStmt(cast<CaseStmt>(S)); + + case Stmt::ChooseExprClass: + return VisitChooseExpr(cast<ChooseExpr>(S), asc); + + case Stmt::CompoundStmtClass: + return VisitCompoundStmt(cast<CompoundStmt>(S)); + + case Stmt::ConditionalOperatorClass: + return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); + + case Stmt::ContinueStmtClass: + return VisitContinueStmt(cast<ContinueStmt>(S)); + + case Stmt::CXXCatchStmtClass: + return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); + + case Stmt::CXXMemberCallExprClass: + return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); + + case Stmt::CXXThrowExprClass: + return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); + + case Stmt::CXXTryStmtClass: + return VisitCXXTryStmt(cast<CXXTryStmt>(S)); + + case Stmt::DeclStmtClass: + return VisitDeclStmt(cast<DeclStmt>(S)); + + case Stmt::DefaultStmtClass: + return VisitDefaultStmt(cast<DefaultStmt>(S)); + + case Stmt::DoStmtClass: + return VisitDoStmt(cast<DoStmt>(S)); + + case Stmt::ForStmtClass: + return VisitForStmt(cast<ForStmt>(S)); + + case Stmt::GotoStmtClass: + return VisitGotoStmt(cast<GotoStmt>(S)); + + case Stmt::IfStmtClass: + return VisitIfStmt(cast<IfStmt>(S)); + + case Stmt::IndirectGotoStmtClass: + return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); + + case Stmt::LabelStmtClass: + return VisitLabelStmt(cast<LabelStmt>(S)); + + case Stmt::MemberExprClass: + return VisitMemberExpr(cast<MemberExpr>(S), asc); + + case Stmt::ObjCAtCatchStmtClass: + return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); + + case Stmt::ObjCAtSynchronizedStmtClass: + return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); + + case Stmt::ObjCAtThrowStmtClass: + return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); + + case Stmt::ObjCAtTryStmtClass: + return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); + + case Stmt::ObjCForCollectionStmtClass: + return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); + + case Stmt::ParenExprClass: + S = cast<ParenExpr>(S)->getSubExpr(); + goto tryAgain; + + case Stmt::NullStmtClass: + return Block; + + case Stmt::ReturnStmtClass: + return VisitReturnStmt(cast<ReturnStmt>(S)); + + case Stmt::SizeOfAlignOfExprClass: + return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); + + case Stmt::StmtExprClass: + return VisitStmtExpr(cast<StmtExpr>(S), asc); + + case Stmt::SwitchStmtClass: + return VisitSwitchStmt(cast<SwitchStmt>(S)); + + case Stmt::WhileStmtClass: + return VisitWhileStmt(cast<WhileStmt>(S)); + } +} + +CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, S, asc); + } + + return VisitChildren(S); +} + +/// VisitChildren - Visit the children of a Stmt. +CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { + CFGBlock *B = Block; + for (Stmt::child_iterator I = Terminator->child_begin(), + E = Terminator->child_end(); I != E; ++I) { + if (*I) B = Visit(*I); + } + return B; +} + +CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, + AddStmtChoice asc) { + AddressTakenLabels.insert(A->getLabel()); + + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, A, asc); + } + + return Block; +} + +CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, + AddStmtChoice asc) { + if (B->isLogicalOp()) { // && or || + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + AppendStmt(ConfluenceBlock, B, asc); + + if (!FinishBlock(ConfluenceBlock)) + return 0; + + // create the block evaluating the LHS + CFGBlock* LHSBlock = createBlock(false); + LHSBlock->setTerminator(B); + + // create the block evaluating the RHS + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* RHSBlock = addStmt(B->getRHS()); + + if (RHSBlock) { + if (!FinishBlock(RHSBlock)) + return 0; + } + else { + // Create an empty block for cases where the RHS doesn't require + // any explicit statements in the CFG. + RHSBlock = createBlock(); + } + + // See if this is a known constant. + TryResult KnownVal = TryEvaluateBool(B->getLHS()); + if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) + KnownVal.negate(); + + // Now link the LHSBlock with RHSBlock. + if (B->getOpcode() == BinaryOperator::LOr) { + AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + } else { + assert(B->getOpcode() == BinaryOperator::LAnd); + AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + } + + // Generate the blocks for evaluating the LHS. + Block = LHSBlock; + return addStmt(B->getLHS()); + } + else if (B->getOpcode() == BinaryOperator::Comma) { // , + autoCreateBlock(); + AppendStmt(Block, B, asc); + addStmt(B->getRHS()); + return addStmt(B->getLHS()); + } + + return VisitStmt(B, asc); +} + +CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, E, asc); + } + return Block; +} + +CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { + // "break" is a control-flow statement. Thus we stop processing the current + // block. + if (Block && !FinishBlock(Block)) + return 0; + + // Now create a new block that ends with the break statement. + Block = createBlock(false); + Block->setTerminator(B); + + // If there is no target for the break, then we are looking at an incomplete + // AST. This means that the CFG cannot be constructed. + if (BreakTargetBlock) + AddSuccessor(Block, BreakTargetBlock); + else + badCFG = true; + + + return Block; +} + +static bool CanThrow(Expr *E) { + QualType Ty = E->getType(); + if (Ty->isFunctionPointerType()) + Ty = Ty->getAs<PointerType>()->getPointeeType(); + else if (Ty->isBlockPointerType()) + Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); + + const FunctionType *FT = Ty->getAs<FunctionType>(); + if (FT) { + if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) + if (Proto->hasEmptyExceptionSpec()) + return false; + } + return true; +} + +CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { + // If this is a call to a no-return function, this stops the block here. + bool NoReturn = false; + if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { + NoReturn = true; + } + + bool AddEHEdge = false; + + // Languages without exceptions are assumed to not throw. + if (Context->getLangOptions().Exceptions) { + if (AddEHEdges) + AddEHEdge = true; + } + + if (FunctionDecl *FD = C->getDirectCallee()) { + if (FD->hasAttr<NoReturnAttr>()) + NoReturn = true; + if (FD->hasAttr<NoThrowAttr>()) + AddEHEdge = false; + } + + if (!CanThrow(C->getCallee())) + AddEHEdge = false; + + if (!NoReturn && !AddEHEdge) + return VisitStmt(C, AddStmtChoice::AlwaysAdd); + + if (Block) { + Succ = Block; + if (!FinishBlock(Block)) + return 0; + } + + Block = createBlock(!NoReturn); + AppendStmt(Block, C, asc); + + if (NoReturn) { + // Wire this to the exit block directly. + AddSuccessor(Block, &cfg->getExit()); + } + if (AddEHEdge) { + // Add exceptional edges. + if (TryTerminatedBlock) + AddSuccessor(Block, TryTerminatedBlock); + else + AddSuccessor(Block, &cfg->getExit()); + } + + return VisitChildren(C); +} + +CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, + AddStmtChoice asc) { + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + AppendStmt(ConfluenceBlock, C, asc); + if (!FinishBlock(ConfluenceBlock)) + return 0; + + asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue + : AddStmtChoice::AlwaysAdd; + + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* LHSBlock = addStmt(C->getLHS(), asc); + if (!FinishBlock(LHSBlock)) + return 0; + + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* RHSBlock = addStmt(C->getRHS(), asc); + if (!FinishBlock(RHSBlock)) + return 0; + + Block = createBlock(false); + // See if this is a known constant. + const TryResult& KnownVal = TryEvaluateBool(C->getCond()); + AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); + AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); + Block->setTerminator(C); + return addStmt(C->getCond()); +} + + +CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { + EndScope(C); + + CFGBlock* LastBlock = Block; + + for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); + I != E; ++I ) { + LastBlock = addStmt(*I); + + if (badCFG) + return NULL; + } + + LastBlock = StartScope(C, LastBlock); + + return LastBlock; +} + +CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, + AddStmtChoice asc) { + // Create the confluence block that will "merge" the results of the ternary + // expression. + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + AppendStmt(ConfluenceBlock, C, asc); + if (!FinishBlock(ConfluenceBlock)) + return 0; + + asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue + : AddStmtChoice::AlwaysAdd; + + // Create a block for the LHS expression if there is an LHS expression. A + // GCC extension allows LHS to be NULL, causing the condition to be the + // value that is returned instead. + // e.g: x ?: y is shorthand for: x ? x : y; + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* LHSBlock = NULL; + if (C->getLHS()) { + LHSBlock = addStmt(C->getLHS(), asc); + if (!FinishBlock(LHSBlock)) + return 0; + Block = NULL; + } + + // Create the block for the RHS expression. + Succ = ConfluenceBlock; + CFGBlock* RHSBlock = addStmt(C->getRHS(), asc); + if (!FinishBlock(RHSBlock)) + return 0; + + // Create the block that will contain the condition. + Block = createBlock(false); + + // See if this is a known constant. + const TryResult& KnownVal = TryEvaluateBool(C->getCond()); + if (LHSBlock) { + AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); + } else { + if (KnownVal.isFalse()) { + // If we know the condition is false, add NULL as the successor for + // the block containing the condition. In this case, the confluence + // block will have just one predecessor. + AddSuccessor(Block, 0); + assert(ConfluenceBlock->pred_size() == 1); + } else { + // If we have no LHS expression, add the ConfluenceBlock as a direct + // successor for the block containing the condition. Moreover, we need to + // reverse the order of the predecessors in the ConfluenceBlock because + // the RHSBlock will have been added to the succcessors already, and we + // want the first predecessor to the the block containing the expression + // for the case when the ternary expression evaluates to true. + AddSuccessor(Block, ConfluenceBlock); + assert(ConfluenceBlock->pred_size() == 2); + std::reverse(ConfluenceBlock->pred_begin(), + ConfluenceBlock->pred_end()); + } + } + + AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); + Block->setTerminator(C); + return addStmt(C->getCond()); +} + +CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { + autoCreateBlock(); + + if (DS->isSingleDecl()) { + AppendStmt(Block, DS); + return VisitDeclSubExpr(DS->getSingleDecl()); + } + + CFGBlock *B = 0; + + // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. + typedef llvm::SmallVector<Decl*,10> BufTy; + BufTy Buf(DS->decl_begin(), DS->decl_end()); + + for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { + // Get the alignment of the new DeclStmt, padding out to >=8 bytes. + unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 + ? 8 : llvm::AlignOf<DeclStmt>::Alignment; + + // Allocate the DeclStmt using the BumpPtrAllocator. It will get + // automatically freed with the CFG. + DeclGroupRef DG(*I); + Decl *D = *I; + void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); + DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); + + // Append the fake DeclStmt to block. + AppendStmt(Block, DSNew); + B = VisitDeclSubExpr(D); + } + + return B; +} + +/// VisitDeclSubExpr - Utility method to add block-level expressions for +/// initializers in Decls. +CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { + assert(Block); + + VarDecl *VD = dyn_cast<VarDecl>(D); + + if (!VD) + return Block; + + Expr *Init = VD->getInit(); + + if (Init) { + AddStmtChoice::Kind k = + VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd + : AddStmtChoice::NotAlwaysAdd; + Visit(Init, AddStmtChoice(k)); + } + + // If the type of VD is a VLA, then we must process its size expressions. + for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; + VA = FindVA(VA->getElementType().getTypePtr())) + Block = addStmt(VA->getSizeExpr()); + + return Block; +} + +CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { + // We may see an if statement in the middle of a basic block, or it may be the + // first statement we are processing. In either case, we create a new basic + // block. First, we create the blocks for the then...else statements, and + // then we create the block containing the if statement. If we were in the + // middle of a block, we stop processing that block. That block is then the + // implicit successor for the "then" and "else" clauses. + + // The block we were proccessing is now finished. Make it the successor + // block. + if (Block) { + Succ = Block; + if (!FinishBlock(Block)) + return 0; + } + + // Process the false branch. + CFGBlock* ElseBlock = Succ; + + if (Stmt* Else = I->getElse()) { + SaveAndRestore<CFGBlock*> sv(Succ); + + // NULL out Block so that the recursive call to Visit will + // create a new basic block. + Block = NULL; + ElseBlock = addStmt(Else); + + if (!ElseBlock) // Can occur when the Else body has all NullStmts. + ElseBlock = sv.get(); + else if (Block) { + if (!FinishBlock(ElseBlock)) + return 0; + } + } + + // Process the true branch. + CFGBlock* ThenBlock; + { + Stmt* Then = I->getThen(); + assert(Then); + SaveAndRestore<CFGBlock*> sv(Succ); + Block = NULL; + ThenBlock = addStmt(Then); + + if (!ThenBlock) { + // We can reach here if the "then" body has all NullStmts. + // Create an empty block so we can distinguish between true and false + // branches in path-sensitive analyses. + ThenBlock = createBlock(false); + AddSuccessor(ThenBlock, sv.get()); + } else if (Block) { + if (!FinishBlock(ThenBlock)) + return 0; + } + } + + // Now create a new block containing the if statement. + Block = createBlock(false); + + // Set the terminator of the new block to the If statement. + Block->setTerminator(I); + + // See if this is a known constant. + const TryResult &KnownVal = TryEvaluateBool(I->getCond()); + + // Now add the successors. + AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); + AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); + + // Add the condition as the last statement in the new block. This may create + // new blocks as the condition may contain control-flow. Any newly created + // blocks will be pointed to be "Block". + Block = addStmt(I->getCond()); + + // Finally, if the IfStmt contains a condition variable, add both the IfStmt + // and the condition variable initialization to the CFG. + if (VarDecl *VD = I->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); + addStmt(Init); + } + } + + return Block; +} + + +CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { + // If we were in the middle of a block we stop processing that block. + // + // NOTE: If a "return" appears in the middle of a block, this means that the + // code afterwards is DEAD (unreachable). We still keep a basic block + // for that code; a simple "mark-and-sweep" from the entry block will be + // able to report such dead blocks. + if (Block) + FinishBlock(Block); + + // Create the new block. + Block = createBlock(false); + + // The Exit block is the only successor. + AddSuccessor(Block, &cfg->getExit()); + + // Add the return statement to the block. This may create new blocks if R + // contains control-flow (short-circuit operations). + return VisitStmt(R, AddStmtChoice::AlwaysAdd); +} + +CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { + // Get the block of the labeled statement. Add it to our map. + addStmt(L->getSubStmt()); + CFGBlock* LabelBlock = Block; + + if (!LabelBlock) // This can happen when the body is empty, i.e. + LabelBlock = createBlock(); // scopes that only contains NullStmts. + + assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); + LabelMap[ L ] = LabelBlock; + + // Labels partition blocks, so this is the end of the basic block we were + // processing (L is the block's label). Because this is label (and we have + // already processed the substatement) there is no extra control-flow to worry + // about. + LabelBlock->setLabel(L); + if (!FinishBlock(LabelBlock)) + return 0; + + // We set Block to NULL to allow lazy creation of a new block (if necessary); + Block = NULL; + + // This block is now the implicit successor of other blocks. + Succ = LabelBlock; + + return LabelBlock; +} + +CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { + // Goto is a control-flow statement. Thus we stop processing the current + // block and create a new one. + if (Block) + FinishBlock(Block); + + Block = createBlock(false); + Block->setTerminator(G); + + // If we already know the mapping to the label block add the successor now. + LabelMapTy::iterator I = LabelMap.find(G->getLabel()); + + if (I == LabelMap.end()) + // We will need to backpatch this block later. + BackpatchBlocks.push_back(Block); + else + AddSuccessor(Block, I->second); + + return Block; +} + +CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { + CFGBlock* LoopSuccessor = NULL; + + // "for" is a control-flow statement. Thus we stop processing the current + // block. + if (Block) { + if (!FinishBlock(Block)) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Save the current value for the break targets. + // All breaks should go to the code following the loop. + SaveAndRestore<CFGBlock*> save_break(BreakTargetBlock); + BreakTargetBlock = LoopSuccessor; + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(F); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. + if (Stmt* C = F->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + assert(Block == EntryConditionBlock); + + // If this block contains a condition variable, add both the condition + // variable and initializer to the CFG. + if (VarDecl *VD = F->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); + EntryConditionBlock = addStmt(Init); + assert(Block == EntryConditionBlock); + } + } + + if (Block) { + if (!FinishBlock(EntryConditionBlock)) + return 0; + } + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // See if this is a known constant. + TryResult KnownVal(true); + + if (F->getCond()) + KnownVal = TryEvaluateBool(F->getCond()); + + // Now create the loop body. + { + assert(F->getBody()); + + // Save the current values for Block, Succ, and continue targets. + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), + save_continue(ContinueTargetBlock); + + // Create a new block to contain the (bottom) of the loop body. + Block = NULL; + + if (Stmt* I = F->getInc()) { + // Generate increment code in its own basic block. This is the target of + // continue statements. + Succ = addStmt(I); + } else { + // No increment code. Create a special, empty, block that is used as the + // target block for "looping back" to the start of the loop. + assert(Succ == EntryConditionBlock); + Succ = createBlock(); + } + + // Finish up the increment (or empty) block if it hasn't been already. + if (Block) { + assert(Block == Succ); + if (!FinishBlock(Block)) + return 0; + Block = 0; + } + + ContinueTargetBlock = Succ; + + // The starting block for the loop increment is the block that should + // represent the 'loop target' for looping back to the start of the loop. + ContinueTargetBlock->setLoopTarget(F); + + // Now populate the body block, and in the process create new blocks as we + // walk the body of the loop. + CFGBlock* BodyBlock = addStmt(F->getBody()); + + if (!BodyBlock) + BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" + else if (Block && !FinishBlock(BodyBlock)) + return 0; + + // This new body block is a successor to our "exit" condition block. + AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); + } + + // Link up the condition block with the code that follows the loop. (the + // false branch). + AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // If the loop contains initialization, create a new block for those + // statements. This block can also contain statements that precede the loop. + if (Stmt* I = F->getInit()) { + Block = createBlock(); + return addStmt(I); + } else { + // There is no loop initialization. We are thus basically a while loop. + // NULL out Block to force lazy block construction. + Block = NULL; + Succ = EntryConditionBlock; + return EntryConditionBlock; + } +} + +CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, M, asc); + } + return Visit(M->getBase(), + M->isArrow() ? AddStmtChoice::NotAlwaysAdd + : AddStmtChoice::AsLValueNotAlwaysAdd); +} + +CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { + // Objective-C fast enumeration 'for' statements: + // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC + // + // for ( Type newVariable in collection_expression ) { statements } + // + // becomes: + // + // prologue: + // 1. collection_expression + // T. jump to loop_entry + // loop_entry: + // 1. side-effects of element expression + // 1. ObjCForCollectionStmt [performs binding to newVariable] + // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] + // TB: + // statements + // T. jump to loop_entry + // FB: + // what comes after + // + // and + // + // Type existingItem; + // for ( existingItem in expression ) { statements } + // + // becomes: + // + // the same with newVariable replaced with existingItem; the binding works + // the same except that for one ObjCForCollectionStmt::getElement() returns + // a DeclStmt and the other returns a DeclRefExpr. + // + + CFGBlock* LoopSuccessor = 0; + + if (Block) { + if (!FinishBlock(Block)) + return 0; + LoopSuccessor = Block; + Block = 0; + } else + LoopSuccessor = Succ; + + // Build the condition blocks. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(S); + + // The last statement in the block should be the ObjCForCollectionStmt, which + // performs the actual binding to 'element' and determines if there are any + // more items in the collection. + AppendStmt(ExitConditionBlock, S); + Block = ExitConditionBlock; + + // Walk the 'element' expression to see if there are any side-effects. We + // generate new blocks as necesary. We DON'T add the statement by default to + // the CFG unless it contains control-flow. + EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); + if (Block) { + if (!FinishBlock(EntryConditionBlock)) + return 0; + Block = 0; + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // Now create the true branch. + { + // Save the current values for Succ, continue and break targets. + SaveAndRestore<CFGBlock*> save_Succ(Succ), + save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); + + BreakTargetBlock = LoopSuccessor; + ContinueTargetBlock = EntryConditionBlock; + + CFGBlock* BodyBlock = addStmt(S->getBody()); + + if (!BodyBlock) + BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" + else if (Block) { + if (!FinishBlock(BodyBlock)) + return 0; + } + + // This new body block is a successor to our "exit" condition block. + AddSuccessor(ExitConditionBlock, BodyBlock); + } + + // Link up the condition block with the code that follows the loop. + // (the false branch). + AddSuccessor(ExitConditionBlock, LoopSuccessor); + + // Now create a prologue block to contain the collection expression. + Block = createBlock(); + return addStmt(S->getCollection()); +} + +CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { + // FIXME: Add locking 'primitives' to CFG for @synchronized. + + // Inline the body. + CFGBlock *SyncBlock = addStmt(S->getSynchBody()); + + // The sync body starts its own basic block. This makes it a little easier + // for diagnostic clients. + if (SyncBlock) { + if (!FinishBlock(SyncBlock)) + return 0; + + Block = 0; + Succ = SyncBlock; + } + + // Inline the sync expression. + return addStmt(S->getSynchExpr()); +} + +CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { + // FIXME + return NYS(); +} + +CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { + CFGBlock* LoopSuccessor = NULL; + + // "while" is a control-flow statement. Thus we stop processing the current + // block. + if (Block) { + if (!FinishBlock(Block)) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(W); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. Thus we update + // "Succ" after adding the condition. + if (Stmt* C = W->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + assert(Block == EntryConditionBlock); + + // If this block contains a condition variable, add both the condition + // variable and initializer to the CFG. + if (VarDecl *VD = W->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); + EntryConditionBlock = addStmt(Init); + assert(Block == EntryConditionBlock); + } + } + + if (Block) { + if (!FinishBlock(EntryConditionBlock)) + return 0; + } + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // See if this is a known constant. + const TryResult& KnownVal = TryEvaluateBool(W->getCond()); + + // Process the loop body. + { + assert(W->getBody()); + + // Save the current values for Block, Succ, and continue and break targets + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), + save_continue(ContinueTargetBlock), + save_break(BreakTargetBlock); + + // Create an empty block to represent the transition block for looping back + // to the head of the loop. + Block = 0; + assert(Succ == EntryConditionBlock); + Succ = createBlock(); + Succ->setLoopTarget(W); + ContinueTargetBlock = Succ; + + // All breaks should go to the code following the loop. + BreakTargetBlock = LoopSuccessor; + + // NULL out Block to force lazy instantiation of blocks for the body. + Block = NULL; + + // Create the body. The returned block is the entry to the loop body. + CFGBlock* BodyBlock = addStmt(W->getBody()); + + if (!BodyBlock) + BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" + else if (Block) { + if (!FinishBlock(BodyBlock)) + return 0; + } + + // Add the loop body entry as a successor to the condition. + AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); + } + + // Link up the condition block with the code that follows the loop. (the + // false branch). + AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // There can be no more statements in the condition block since we loop back + // to this block. NULL out Block to force lazy creation of another block. + Block = NULL; + + // Return the condition block, which is the dominating block for the loop. + Succ = EntryConditionBlock; + return EntryConditionBlock; +} + + +CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { + // FIXME: For now we pretend that @catch and the code it contains does not + // exit. + return Block; +} + +CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { + // FIXME: This isn't complete. We basically treat @throw like a return + // statement. + + // If we were in the middle of a block we stop processing that block. + if (Block && !FinishBlock(Block)) + return 0; + + // Create the new block. + Block = createBlock(false); + + // The Exit block is the only successor. + AddSuccessor(Block, &cfg->getExit()); + + // Add the statement to the block. This may create new blocks if S contains + // control-flow (short-circuit operations). + return VisitStmt(S, AddStmtChoice::AlwaysAdd); +} + +CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { + // If we were in the middle of a block we stop processing that block. + if (Block && !FinishBlock(Block)) + return 0; + + // Create the new block. + Block = createBlock(false); + + if (TryTerminatedBlock) + // The current try statement is the only successor. + AddSuccessor(Block, TryTerminatedBlock); + else + // otherwise the Exit block is the only successor. + AddSuccessor(Block, &cfg->getExit()); + + // Add the statement to the block. This may create new blocks if S contains + // control-flow (short-circuit operations). + return VisitStmt(T, AddStmtChoice::AlwaysAdd); +} + +CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { + CFGBlock* LoopSuccessor = NULL; + + // "do...while" is a control-flow statement. Thus we stop processing the + // current block. + if (Block) { + if (!FinishBlock(Block)) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(D); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. + if (Stmt* C = D->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + if (Block) { + if (!FinishBlock(EntryConditionBlock)) + return 0; + } + } + + // The condition block is the implicit successor for the loop body. + Succ = EntryConditionBlock; + + // See if this is a known constant. + const TryResult &KnownVal = TryEvaluateBool(D->getCond()); + + // Process the loop body. + CFGBlock* BodyBlock = NULL; + { + assert(D->getBody()); + + // Save the current values for Block, Succ, and continue and break targets + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), + save_continue(ContinueTargetBlock), + save_break(BreakTargetBlock); + + // All continues within this loop should go to the condition block + ContinueTargetBlock = EntryConditionBlock; + + // All breaks should go to the code following the loop. + BreakTargetBlock = LoopSuccessor; + + // NULL out Block to force lazy instantiation of blocks for the body. + Block = NULL; + + // Create the body. The returned block is the entry to the loop body. + BodyBlock = addStmt(D->getBody()); + + if (!BodyBlock) + BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" + else if (Block) { + if (!FinishBlock(BodyBlock)) + return 0; + } + + // Add an intermediate block between the BodyBlock and the + // ExitConditionBlock to represent the "loop back" transition. Create an + // empty block to represent the transition block for looping back to the + // head of the loop. + // FIXME: Can we do this more efficiently without adding another block? + Block = NULL; + Succ = BodyBlock; + CFGBlock *LoopBackBlock = createBlock(); + LoopBackBlock->setLoopTarget(D); + + // Add the loop body entry as a successor to the condition. + AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); + } + + // Link up the condition block with the code that follows the loop. + // (the false branch). + AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // There can be no more statements in the body block(s) since we loop back to + // the body. NULL out Block to force lazy creation of another block. + Block = NULL; + + // Return the loop body, which is the dominating block for the loop. + Succ = BodyBlock; + return BodyBlock; +} + +CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { + // "continue" is a control-flow statement. Thus we stop processing the + // current block. + if (Block && !FinishBlock(Block)) + return 0; + + // Now create a new block that ends with the continue statement. + Block = createBlock(false); + Block->setTerminator(C); + + // If there is no target for the continue, then we are looking at an + // incomplete AST. This means the CFG cannot be constructed. + if (ContinueTargetBlock) + AddSuccessor(Block, ContinueTargetBlock); + else + badCFG = true; + + return Block; +} + +CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, + AddStmtChoice asc) { + + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, E); + } + + // VLA types have expressions that must be evaluated. + if (E->isArgumentType()) { + for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); + VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) + addStmt(VA->getSizeExpr()); + } + + return Block; +} + +/// VisitStmtExpr - Utility method to handle (nested) statement +/// expressions (a GCC extension). +CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + AppendStmt(Block, SE); + } + return VisitCompoundStmt(SE->getSubStmt()); +} + +CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { + // "switch" is a control-flow statement. Thus we stop processing the current + // block. + CFGBlock* SwitchSuccessor = NULL; + + if (Block) { + if (!FinishBlock(Block)) + return 0; + SwitchSuccessor = Block; + } else SwitchSuccessor = Succ; + + // Save the current "switch" context. + SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), + save_break(BreakTargetBlock), + save_default(DefaultCaseBlock); + + // Set the "default" case to be the block after the switch statement. If the + // switch statement contains a "default:", this value will be overwritten with + // the block for that code. + DefaultCaseBlock = SwitchSuccessor; + + // Create a new block that will contain the switch statement. + SwitchTerminatedBlock = createBlock(false); + + // Now process the switch body. The code after the switch is the implicit + // successor. + Succ = SwitchSuccessor; + BreakTargetBlock = SwitchSuccessor; + + // When visiting the body, the case statements should automatically get linked + // up to the switch. We also don't keep a pointer to the body, since all + // control-flow from the switch goes to case/default statements. + assert(Terminator->getBody() && "switch must contain a non-NULL body"); + Block = NULL; + CFGBlock *BodyBlock = addStmt(Terminator->getBody()); + if (Block) { + if (!FinishBlock(BodyBlock)) + return 0; + } + + // If we have no "default:" case, the default transition is to the code + // following the switch body. + AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); + + // Add the terminator and condition in the switch block. + SwitchTerminatedBlock->setTerminator(Terminator); + assert(Terminator->getCond() && "switch condition must be non-NULL"); + Block = SwitchTerminatedBlock; + Block = addStmt(Terminator->getCond()); + + // Finally, if the SwitchStmt contains a condition variable, add both the + // SwitchStmt and the condition variable initialization to the CFG. + if (VarDecl *VD = Terminator->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); + addStmt(Init); + } + } + + return Block; +} + +CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { + // CaseStmts are essentially labels, so they are the first statement in a + // block. + + if (CS->getSubStmt()) + addStmt(CS->getSubStmt()); + + CFGBlock* CaseBlock = Block; + if (!CaseBlock) + CaseBlock = createBlock(); + + // Cases statements partition blocks, so this is the top of the basic block we + // were processing (the "case XXX:" is the label). + CaseBlock->setLabel(CS); + + if (!FinishBlock(CaseBlock)) + return 0; + + // Add this block to the list of successors for the block with the switch + // statement. + assert(SwitchTerminatedBlock); + AddSuccessor(SwitchTerminatedBlock, CaseBlock); + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + // This block is now the implicit successor of other blocks. + Succ = CaseBlock; + + return CaseBlock; +} + +CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { + if (Terminator->getSubStmt()) + addStmt(Terminator->getSubStmt()); + + DefaultCaseBlock = Block; + + if (!DefaultCaseBlock) + DefaultCaseBlock = createBlock(); + + // Default statements partition blocks, so this is the top of the basic block + // we were processing (the "default:" is the label). + DefaultCaseBlock->setLabel(Terminator); + + if (!FinishBlock(DefaultCaseBlock)) + return 0; + + // Unlike case statements, we don't add the default block to the successors + // for the switch statement immediately. This is done when we finish + // processing the switch statement. This allows for the default case + // (including a fall-through to the code after the switch statement) to always + // be the last successor of a switch-terminated block. + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + // This block is now the implicit successor of other blocks. + Succ = DefaultCaseBlock; + + return DefaultCaseBlock; +} + +CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { + // "try"/"catch" is a control-flow statement. Thus we stop processing the + // current block. + CFGBlock* TrySuccessor = NULL; + + if (Block) { + if (!FinishBlock(Block)) + return 0; + TrySuccessor = Block; + } else TrySuccessor = Succ; + + CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; + + // Create a new block that will contain the try statement. + CFGBlock *NewTryTerminatedBlock = createBlock(false); + // Add the terminator in the try block. + NewTryTerminatedBlock->setTerminator(Terminator); + + bool HasCatchAll = false; + for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { + // The code after the try is the implicit successor. + Succ = TrySuccessor; + CXXCatchStmt *CS = Terminator->getHandler(h); + if (CS->getExceptionDecl() == 0) { + HasCatchAll = true; + } + Block = NULL; + CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); + if (CatchBlock == 0) + return 0; + // Add this block to the list of successors for the block with the try + // statement. + AddSuccessor(NewTryTerminatedBlock, CatchBlock); + } + if (!HasCatchAll) { + if (PrevTryTerminatedBlock) + AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); + else + AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); + } + + // The code after the try is the implicit successor. + Succ = TrySuccessor; + + // Save the current "try" context. + SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); + TryTerminatedBlock = NewTryTerminatedBlock; + + assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); + Block = NULL; + Block = addStmt(Terminator->getTryBlock()); + return Block; +} + +CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { + // CXXCatchStmt are treated like labels, so they are the first statement in a + // block. + + if (CS->getHandlerBlock()) + addStmt(CS->getHandlerBlock()); + + CFGBlock* CatchBlock = Block; + if (!CatchBlock) + CatchBlock = createBlock(); + + CatchBlock->setLabel(CS); + + if (!FinishBlock(CatchBlock)) + return 0; + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + return CatchBlock; +} + +CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, + AddStmtChoice asc) { + AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue + : AddStmtChoice::AlwaysAdd; + autoCreateBlock(); + AppendStmt(Block, C, AddStmtChoice(K)); + return VisitChildren(C); +} + +CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { + // Lazily create the indirect-goto dispatch block if there isn't one already. + CFGBlock* IBlock = cfg->getIndirectGotoBlock(); + + if (!IBlock) { + IBlock = createBlock(false); + cfg->setIndirectGotoBlock(IBlock); + } + + // IndirectGoto is a control-flow statement. Thus we stop processing the + // current block and create a new one. + if (Block && !FinishBlock(Block)) + return 0; + + Block = createBlock(false); + Block->setTerminator(I); + AddSuccessor(Block, IBlock); + return addStmt(I->getTarget()); +} + +} // end anonymous namespace + +/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has +/// no successors or predecessors. If this is the first block created in the +/// CFG, it is automatically set to be the Entry and Exit of the CFG. +CFGBlock* CFG::createBlock() { + bool first_block = begin() == end(); + + // Create the block. + CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); + new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); + Blocks.push_back(Mem, BlkBVC); + + // If this is the first block, set it as the Entry and Exit. + if (first_block) + Entry = Exit = &back(); + + // Return the block. + return &back(); +} + +/// buildCFG - Constructs a CFG from an AST. Ownership of the returned +/// CFG is returned to the caller. +CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, + bool AddEHEdges, bool AddScopes) { + CFGBuilder Builder; + return Builder.buildCFG(D, Statement, C, AddEHEdges, AddScopes); +} + +//===----------------------------------------------------------------------===// +// CFG: Queries for BlkExprs. +//===----------------------------------------------------------------------===// + +namespace { + typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; +} + +static void FindSubExprAssignments(Stmt *S, + llvm::SmallPtrSet<Expr*,50>& Set) { + if (!S) + return; + + for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { + Stmt *child = *I; + if (!child) + continue; + + if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) + if (B->isAssignmentOp()) Set.insert(B); + + FindSubExprAssignments(child, Set); + } +} + +static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { + BlkExprMapTy* M = new BlkExprMapTy(); + + // Look for assignments that are used as subexpressions. These are the only + // assignments that we want to *possibly* register as a block-level + // expression. Basically, if an assignment occurs both in a subexpression and + // at the block-level, it is a block-level expression. + llvm::SmallPtrSet<Expr*,50> SubExprAssignments; + + for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) + for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) + FindSubExprAssignments(*BI, SubExprAssignments); + + for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { + + // Iterate over the statements again on identify the Expr* and Stmt* at the + // block-level that are block-level expressions. + + for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) + if (Expr* Exp = dyn_cast<Expr>(*BI)) { + + if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { + // Assignment expressions that are not nested within another + // expression are really "statements" whose value is never used by + // another expression. + if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) + continue; + } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { + // Special handling for statement expressions. The last statement in + // the statement expression is also a block-level expr. + const CompoundStmt* C = Terminator->getSubStmt(); + if (!C->body_empty()) { + unsigned x = M->size(); + (*M)[C->body_back()] = x; + } + } + + unsigned x = M->size(); + (*M)[Exp] = x; + } + + // Look at terminators. The condition is a block-level expression. + + Stmt* S = (*I)->getTerminatorCondition(); + + if (S && M->find(S) == M->end()) { + unsigned x = M->size(); + (*M)[S] = x; + } + } + + return M; +} + +CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { + assert(S != NULL); + if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } + + BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); + BlkExprMapTy::iterator I = M->find(S); + return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); +} + +unsigned CFG::getNumBlkExprs() { + if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) + return M->size(); + else { + // We assume callers interested in the number of BlkExprs will want + // the map constructed if it doesn't already exist. + BlkExprMap = (void*) PopulateBlkExprMap(*this); + return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); + } +} + +//===----------------------------------------------------------------------===// +// Cleanup: CFG dstor. +//===----------------------------------------------------------------------===// + +CFG::~CFG() { + delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); +} + +//===----------------------------------------------------------------------===// +// CFG pretty printing +//===----------------------------------------------------------------------===// + +namespace { + +class StmtPrinterHelper : public PrinterHelper { + typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; + StmtMapTy StmtMap; + signed CurrentBlock; + unsigned CurrentStmt; + const LangOptions &LangOpts; +public: + + StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) + : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { + for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { + unsigned j = 1; + for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; + BI != BEnd; ++BI, ++j ) + StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); + } + } + + virtual ~StmtPrinterHelper() {} + + const LangOptions &getLangOpts() const { return LangOpts; } + void setBlockID(signed i) { CurrentBlock = i; } + void setStmtID(unsigned i) { CurrentStmt = i; } + + virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { + + StmtMapTy::iterator I = StmtMap.find(Terminator); + + if (I == StmtMap.end()) + return false; + + if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock + && I->second.second == CurrentStmt) { + return false; + } + + OS << "[B" << I->second.first << "." << I->second.second << "]"; + return true; + } +}; +} // end anonymous namespace + + +namespace { +class CFGBlockTerminatorPrint + : public StmtVisitor<CFGBlockTerminatorPrint,void> { + + llvm::raw_ostream& OS; + StmtPrinterHelper* Helper; + PrintingPolicy Policy; +public: + CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, + const PrintingPolicy &Policy) + : OS(os), Helper(helper), Policy(Policy) {} + + void VisitIfStmt(IfStmt* I) { + OS << "if "; + I->getCond()->printPretty(OS,Helper,Policy); + } + + // Default case. + void VisitStmt(Stmt* Terminator) { + Terminator->printPretty(OS, Helper, Policy); + } + + void VisitForStmt(ForStmt* F) { + OS << "for (" ; + if (F->getInit()) + OS << "..."; + OS << "; "; + if (Stmt* C = F->getCond()) + C->printPretty(OS, Helper, Policy); + OS << "; "; + if (F->getInc()) + OS << "..."; + OS << ")"; + } + + void VisitWhileStmt(WhileStmt* W) { + OS << "while " ; + if (Stmt* C = W->getCond()) + C->printPretty(OS, Helper, Policy); + } + + void VisitDoStmt(DoStmt* D) { + OS << "do ... while "; + if (Stmt* C = D->getCond()) + C->printPretty(OS, Helper, Policy); + } + + void VisitSwitchStmt(SwitchStmt* Terminator) { + OS << "switch "; + Terminator->getCond()->printPretty(OS, Helper, Policy); + } + + void VisitCXXTryStmt(CXXTryStmt* CS) { + OS << "try ..."; + } + + void VisitConditionalOperator(ConditionalOperator* C) { + C->getCond()->printPretty(OS, Helper, Policy); + OS << " ? ... : ..."; + } + + void VisitChooseExpr(ChooseExpr* C) { + OS << "__builtin_choose_expr( "; + C->getCond()->printPretty(OS, Helper, Policy); + OS << " )"; + } + + void VisitIndirectGotoStmt(IndirectGotoStmt* I) { + OS << "goto *"; + I->getTarget()->printPretty(OS, Helper, Policy); + } + + void VisitBinaryOperator(BinaryOperator* B) { + if (!B->isLogicalOp()) { + VisitExpr(B); + return; + } + + B->getLHS()->printPretty(OS, Helper, Policy); + + switch (B->getOpcode()) { + case BinaryOperator::LOr: + OS << " || ..."; + return; + case BinaryOperator::LAnd: + OS << " && ..."; + return; + default: + assert(false && "Invalid logical operator."); + } + } + + void VisitExpr(Expr* E) { + E->printPretty(OS, Helper, Policy); + } +}; +} // end anonymous namespace + + +static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, + const CFGElement &E) { + Stmt *Terminator = E; + + if (E.asStartScope()) { + OS << "start scope\n"; + return; + } + if (E.asEndScope()) { + OS << "end scope\n"; + return; + } + + if (Helper) { + // special printing for statement-expressions. + if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { + CompoundStmt* Sub = SE->getSubStmt(); + + if (Sub->child_begin() != Sub->child_end()) { + OS << "({ ... ; "; + Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); + OS << " })\n"; + return; + } + } + + // special printing for comma expressions. + if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { + if (B->getOpcode() == BinaryOperator::Comma) { + OS << "... , "; + Helper->handledStmt(B->getRHS(),OS); + OS << '\n'; + return; + } + } + } + + Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); + + // Expressions need a newline. + if (isa<Expr>(Terminator)) OS << '\n'; +} + +static void print_block(llvm::raw_ostream& OS, const CFG* cfg, + const CFGBlock& B, + StmtPrinterHelper* Helper, bool print_edges) { + + if (Helper) Helper->setBlockID(B.getBlockID()); + + // Print the header. + OS << "\n [ B" << B.getBlockID(); + + if (&B == &cfg->getEntry()) + OS << " (ENTRY) ]\n"; + else if (&B == &cfg->getExit()) + OS << " (EXIT) ]\n"; + else if (&B == cfg->getIndirectGotoBlock()) + OS << " (INDIRECT GOTO DISPATCH) ]\n"; + else + OS << " ]\n"; + + // Print the label of this block. + if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { + + if (print_edges) + OS << " "; + + if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) + OS << L->getName(); + else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { + OS << "case "; + C->getLHS()->printPretty(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + if (C->getRHS()) { + OS << " ... "; + C->getRHS()->printPretty(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + } + } else if (isa<DefaultStmt>(Label)) + OS << "default"; + else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { + OS << "catch ("; + if (CS->getExceptionDecl()) + CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), + 0); + else + OS << "..."; + OS << ")"; + + } else + assert(false && "Invalid label statement in CFGBlock."); + + OS << ":\n"; + } + + // Iterate through the statements in the block and print them. + unsigned j = 1; + + for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; + I != E ; ++I, ++j ) { + + // Print the statement # in the basic block and the statement itself. + if (print_edges) + OS << " "; + + OS << llvm::format("%3d", j) << ": "; + + if (Helper) + Helper->setStmtID(j); + + print_stmt(OS,Helper,*I); + } + + // Print the terminator of this block. + if (B.getTerminator()) { + if (print_edges) + OS << " "; + + OS << " T: "; + + if (Helper) Helper->setBlockID(-1); + + CFGBlockTerminatorPrint TPrinter(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); + OS << '\n'; + } + + if (print_edges) { + // Print the predecessors of this block. + OS << " Predecessors (" << B.pred_size() << "):"; + unsigned i = 0; + + for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); + I != E; ++I, ++i) { + + if (i == 8 || (i-8) == 0) + OS << "\n "; + + OS << " B" << (*I)->getBlockID(); + } + + OS << '\n'; + + // Print the successors of this block. + OS << " Successors (" << B.succ_size() << "):"; + i = 0; + + for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); + I != E; ++I, ++i) { + + if (i == 8 || (i-8) % 10 == 0) + OS << "\n "; + + if (*I) + OS << " B" << (*I)->getBlockID(); + else + OS << " NULL"; + } + + OS << '\n'; + } +} + + +/// dump - A simple pretty printer of a CFG that outputs to stderr. +void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } + +/// print - A simple pretty printer of a CFG that outputs to an ostream. +void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { + StmtPrinterHelper Helper(this, LO); + + // Print the entry block. + print_block(OS, this, getEntry(), &Helper, true); + + // Iterate through the CFGBlocks and print them one by one. + for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { + // Skip the entry block, because we already printed it. + if (&(**I) == &getEntry() || &(**I) == &getExit()) + continue; + + print_block(OS, this, **I, &Helper, true); + } + + // Print the exit block. + print_block(OS, this, getExit(), &Helper, true); + OS.flush(); +} + +/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. +void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { + print(llvm::errs(), cfg, LO); +} + +/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. +/// Generally this will only be called from CFG::print. +void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, + const LangOptions &LO) const { + StmtPrinterHelper Helper(cfg, LO); + print_block(OS, cfg, *this, &Helper, true); +} + +/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. +void CFGBlock::printTerminator(llvm::raw_ostream &OS, + const LangOptions &LO) const { + CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); + TPrinter.Visit(const_cast<Stmt*>(getTerminator())); +} + +Stmt* CFGBlock::getTerminatorCondition() { + + if (!Terminator) + return NULL; + + Expr* E = NULL; + + switch (Terminator->getStmtClass()) { + default: + break; + + case Stmt::ForStmtClass: + E = cast<ForStmt>(Terminator)->getCond(); + break; + + case Stmt::WhileStmtClass: + E = cast<WhileStmt>(Terminator)->getCond(); + break; + + case Stmt::DoStmtClass: + E = cast<DoStmt>(Terminator)->getCond(); + break; + + case Stmt::IfStmtClass: + E = cast<IfStmt>(Terminator)->getCond(); + break; + + case Stmt::ChooseExprClass: + E = cast<ChooseExpr>(Terminator)->getCond(); + break; + + case Stmt::IndirectGotoStmtClass: + E = cast<IndirectGotoStmt>(Terminator)->getTarget(); + break; + + case Stmt::SwitchStmtClass: + E = cast<SwitchStmt>(Terminator)->getCond(); + break; + + case Stmt::ConditionalOperatorClass: + E = cast<ConditionalOperator>(Terminator)->getCond(); + break; + + case Stmt::BinaryOperatorClass: // '&&' and '||' + E = cast<BinaryOperator>(Terminator)->getLHS(); + break; + + case Stmt::ObjCForCollectionStmtClass: + return Terminator; + } + + return E ? E->IgnoreParens() : NULL; +} + +bool CFGBlock::hasBinaryBranchTerminator() const { + + if (!Terminator) + return false; + + Expr* E = NULL; + + switch (Terminator->getStmtClass()) { + default: + return false; + + case Stmt::ForStmtClass: + case Stmt::WhileStmtClass: + case Stmt::DoStmtClass: + case Stmt::IfStmtClass: + case Stmt::ChooseExprClass: + case Stmt::ConditionalOperatorClass: + case Stmt::BinaryOperatorClass: + return true; + } + + return E ? E->IgnoreParens() : NULL; +} + + +//===----------------------------------------------------------------------===// +// CFG Graphviz Visualization +//===----------------------------------------------------------------------===// + + +#ifndef NDEBUG +static StmtPrinterHelper* GraphHelper; +#endif + +void CFG::viewCFG(const LangOptions &LO) const { +#ifndef NDEBUG + StmtPrinterHelper H(this, LO); + GraphHelper = &H; + llvm::ViewGraph(this,"CFG"); + GraphHelper = NULL; +#endif +} + +namespace llvm { +template<> +struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { + + DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} + + static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { + +#ifndef NDEBUG + std::string OutSStr; + llvm::raw_string_ostream Out(OutSStr); + print_block(Out,Graph, *Node, GraphHelper, false); + std::string& OutStr = Out.str(); + + if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); + + // Process string output to make it nicer... + for (unsigned i = 0; i != OutStr.length(); ++i) + if (OutStr[i] == '\n') { // Left justify + OutStr[i] = '\\'; + OutStr.insert(OutStr.begin()+i+1, 'l'); + } + + return OutStr; +#else + return ""; +#endif + } +}; +} // end namespace llvm diff --git a/contrib/llvm/tools/clang/lib/Analysis/CMakeLists.txt b/contrib/llvm/tools/clang/lib/Analysis/CMakeLists.txt new file mode 100644 index 0000000..a8e3708 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/CMakeLists.txt @@ -0,0 +1,12 @@ +set(LLVM_NO_RTTI 1) + +add_clang_library(clangAnalysis + AnalysisContext.cpp + CFG.cpp + LiveVariables.cpp + PrintfFormatString.cpp + ReachableCode.cpp + UninitializedValues.cpp + ) + +add_dependencies(clangAnalysis ClangDiagnosticAnalysis ClangStmtNodes) diff --git a/contrib/llvm/tools/clang/lib/Analysis/LiveVariables.cpp b/contrib/llvm/tools/clang/lib/Analysis/LiveVariables.cpp new file mode 100644 index 0000000..01a36a1 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/LiveVariables.cpp @@ -0,0 +1,382 @@ +//=- LiveVariables.cpp - Live Variable Analysis for Source CFGs -*- C++ --*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements Live Variables analysis for source-level CFGs. +// +//===----------------------------------------------------------------------===// + +#include "clang/Analysis/Analyses/LiveVariables.h" +#include "clang/Basic/SourceManager.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/Expr.h" +#include "clang/Analysis/CFG.h" +#include "clang/Analysis/Visitors/CFGRecStmtDeclVisitor.h" +#include "clang/Analysis/FlowSensitive/DataflowSolver.h" +#include "clang/Analysis/Support/SaveAndRestore.h" +#include "clang/Analysis/AnalysisContext.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/Support/raw_ostream.h" + +using namespace clang; + +//===----------------------------------------------------------------------===// +// Useful constants. +//===----------------------------------------------------------------------===// + +static const bool Alive = true; +static const bool Dead = false; + +//===----------------------------------------------------------------------===// +// Dataflow initialization logic. +//===----------------------------------------------------------------------===// + +namespace { +class RegisterDecls + : public CFGRecStmtDeclVisitor<RegisterDecls> { + + LiveVariables::AnalysisDataTy& AD; + + typedef llvm::SmallVector<VarDecl*, 20> AlwaysLiveTy; + AlwaysLiveTy AlwaysLive; + + +public: + RegisterDecls(LiveVariables::AnalysisDataTy& ad) : AD(ad) {} + + ~RegisterDecls() { + + AD.AlwaysLive.resetValues(AD); + + for (AlwaysLiveTy::iterator I = AlwaysLive.begin(), E = AlwaysLive.end(); + I != E; ++ I) + AD.AlwaysLive(*I, AD) = Alive; + } + + void VisitImplicitParamDecl(ImplicitParamDecl* IPD) { + // Register the VarDecl for tracking. + AD.Register(IPD); + } + + void VisitVarDecl(VarDecl* VD) { + // Register the VarDecl for tracking. + AD.Register(VD); + + // Does the variable have global storage? If so, it is always live. + if (VD->hasGlobalStorage()) + AlwaysLive.push_back(VD); + } + + CFG& getCFG() { return AD.getCFG(); } +}; +} // end anonymous namespace + +LiveVariables::LiveVariables(AnalysisContext &AC) { + // Register all referenced VarDecls. + CFG &cfg = *AC.getCFG(); + getAnalysisData().setCFG(cfg); + getAnalysisData().setContext(AC.getASTContext()); + getAnalysisData().AC = &AC; + + RegisterDecls R(getAnalysisData()); + cfg.VisitBlockStmts(R); + + // Register all parameters even if they didn't occur in the function body. + if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(AC.getDecl())) + for (FunctionDecl::param_const_iterator PI = FD->param_begin(), + PE = FD->param_end(); PI != PE; ++PI) + getAnalysisData().Register(*PI); +} + +//===----------------------------------------------------------------------===// +// Transfer functions. +//===----------------------------------------------------------------------===// + +namespace { + +class TransferFuncs : public CFGRecStmtVisitor<TransferFuncs>{ + LiveVariables::AnalysisDataTy& AD; + LiveVariables::ValTy LiveState; +public: + TransferFuncs(LiveVariables::AnalysisDataTy& ad) : AD(ad) {} + + LiveVariables::ValTy& getVal() { return LiveState; } + CFG& getCFG() { return AD.getCFG(); } + + void VisitDeclRefExpr(DeclRefExpr* DR); + void VisitBinaryOperator(BinaryOperator* B); + void VisitBlockExpr(BlockExpr *B); + void VisitAssign(BinaryOperator* B); + void VisitDeclStmt(DeclStmt* DS); + void BlockStmt_VisitObjCForCollectionStmt(ObjCForCollectionStmt* S); + void VisitUnaryOperator(UnaryOperator* U); + void Visit(Stmt *S); + void VisitTerminator(CFGBlock* B); + + /// VisitConditionVariableInit - Handle the initialization of condition + /// variables at branches. Valid statements include IfStmt, ForStmt, + /// WhileStmt, and SwitchStmt. + void VisitConditionVariableInit(Stmt *S); + + void SetTopValue(LiveVariables::ValTy& V) { + V = AD.AlwaysLive; + } + +}; + +void TransferFuncs::Visit(Stmt *S) { + + if (S == getCurrentBlkStmt()) { + + if (AD.Observer) + AD.Observer->ObserveStmt(S,AD,LiveState); + + if (getCFG().isBlkExpr(S)) + LiveState(S, AD) = Dead; + + StmtVisitor<TransferFuncs,void>::Visit(S); + } + else if (!getCFG().isBlkExpr(S)) { + + if (AD.Observer) + AD.Observer->ObserveStmt(S,AD,LiveState); + + StmtVisitor<TransferFuncs,void>::Visit(S); + + } + else { + // For block-level expressions, mark that they are live. + LiveState(S,AD) = Alive; + } +} + +void TransferFuncs::VisitConditionVariableInit(Stmt *S) { + assert(!getCFG().isBlkExpr(S)); + CFGRecStmtVisitor<TransferFuncs>::VisitConditionVariableInit(S); +} + +void TransferFuncs::VisitTerminator(CFGBlock* B) { + + const Stmt* E = B->getTerminatorCondition(); + + if (!E) + return; + + assert (getCFG().isBlkExpr(E)); + LiveState(E, AD) = Alive; +} + +void TransferFuncs::VisitDeclRefExpr(DeclRefExpr* DR) { + if (VarDecl* V = dyn_cast<VarDecl>(DR->getDecl())) + LiveState(V, AD) = Alive; +} + +void TransferFuncs::VisitBlockExpr(BlockExpr *BE) { + AnalysisContext::referenced_decls_iterator I, E; + llvm::tie(I, E) = AD.AC->getReferencedBlockVars(BE->getBlockDecl()); + for ( ; I != E ; ++I) { + DeclBitVector_Types::Idx i = AD.getIdx(*I); + if (i.isValid()) + LiveState.getBit(i) = Alive; + } +} + +void TransferFuncs::VisitBinaryOperator(BinaryOperator* B) { + if (B->isAssignmentOp()) VisitAssign(B); + else VisitStmt(B); +} + +void +TransferFuncs::BlockStmt_VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { + + // This is a block-level expression. Its value is 'dead' before this point. + LiveState(S, AD) = Dead; + + // This represents a 'use' of the collection. + Visit(S->getCollection()); + + // This represents a 'kill' for the variable. + Stmt* Element = S->getElement(); + DeclRefExpr* DR = 0; + VarDecl* VD = 0; + + if (DeclStmt* DS = dyn_cast<DeclStmt>(Element)) + VD = cast<VarDecl>(DS->getSingleDecl()); + else { + Expr* ElemExpr = cast<Expr>(Element)->IgnoreParens(); + if ((DR = dyn_cast<DeclRefExpr>(ElemExpr))) + VD = cast<VarDecl>(DR->getDecl()); + else { + Visit(ElemExpr); + return; + } + } + + if (VD) { + LiveState(VD, AD) = Dead; + if (AD.Observer && DR) { AD.Observer->ObserverKill(DR); } + } +} + + +void TransferFuncs::VisitUnaryOperator(UnaryOperator* U) { + Expr *E = U->getSubExpr(); + + switch (U->getOpcode()) { + case UnaryOperator::PostInc: + case UnaryOperator::PostDec: + case UnaryOperator::PreInc: + case UnaryOperator::PreDec: + // Walk through the subexpressions, blasting through ParenExprs + // until we either find a DeclRefExpr or some non-DeclRefExpr + // expression. + if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(E->IgnoreParens())) + if (VarDecl* VD = dyn_cast<VarDecl>(DR->getDecl())) { + // Treat the --/++ operator as a kill. + if (AD.Observer) { AD.Observer->ObserverKill(DR); } + LiveState(VD, AD) = Alive; + return VisitDeclRefExpr(DR); + } + + // Fall-through. + + default: + return Visit(E); + } +} + +void TransferFuncs::VisitAssign(BinaryOperator* B) { + Expr* LHS = B->getLHS(); + + // Assigning to a variable? + if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(LHS->IgnoreParens())) { + + // Update liveness inforamtion. + unsigned bit = AD.getIdx(DR->getDecl()); + LiveState.getDeclBit(bit) = Dead | AD.AlwaysLive.getDeclBit(bit); + + if (AD.Observer) { AD.Observer->ObserverKill(DR); } + + // Handle things like +=, etc., which also generate "uses" + // of a variable. Do this just by visiting the subexpression. + if (B->getOpcode() != BinaryOperator::Assign) + VisitDeclRefExpr(DR); + } + else // Not assigning to a variable. Process LHS as usual. + Visit(LHS); + + Visit(B->getRHS()); +} + +void TransferFuncs::VisitDeclStmt(DeclStmt* DS) { + // Declarations effectively "kill" a variable since they cannot + // possibly be live before they are declared. + for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE = DS->decl_end(); + DI != DE; ++DI) + if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) { + // Update liveness information by killing the VarDecl. + unsigned bit = AD.getIdx(VD); + LiveState.getDeclBit(bit) = Dead | AD.AlwaysLive.getDeclBit(bit); + + // The initializer is evaluated after the variable comes into scope, but + // before the DeclStmt (which binds the value to the variable). + // Since this is a reverse dataflow analysis, we must evaluate the + // transfer function for this expression after the DeclStmt. If the + // initializer references the variable (which is bad) then we extend + // its liveness. + if (Expr* Init = VD->getInit()) + Visit(Init); + + if (const VariableArrayType* VT = + AD.getContext().getAsVariableArrayType(VD->getType())) { + StmtIterator I(const_cast<VariableArrayType*>(VT)); + StmtIterator E; + for (; I != E; ++I) Visit(*I); + } + } +} + +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// Merge operator: if something is live on any successor block, it is live +// in the current block (a set union). +//===----------------------------------------------------------------------===// + +namespace { + typedef StmtDeclBitVector_Types::Union Merge; + typedef DataflowSolver<LiveVariables, TransferFuncs, Merge> Solver; +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// External interface to run Liveness analysis. +//===----------------------------------------------------------------------===// + +void LiveVariables::runOnCFG(CFG& cfg) { + Solver S(*this); + S.runOnCFG(cfg); +} + +void LiveVariables::runOnAllBlocks(const CFG& cfg, + LiveVariables::ObserverTy* Obs, + bool recordStmtValues) { + Solver S(*this); + SaveAndRestore<LiveVariables::ObserverTy*> SRObs(getAnalysisData().Observer, + Obs); + S.runOnAllBlocks(cfg, recordStmtValues); +} + +//===----------------------------------------------------------------------===// +// liveness queries +// + +bool LiveVariables::isLive(const CFGBlock* B, const VarDecl* D) const { + DeclBitVector_Types::Idx i = getAnalysisData().getIdx(D); + return i.isValid() ? getBlockData(B).getBit(i) : false; +} + +bool LiveVariables::isLive(const ValTy& Live, const VarDecl* D) const { + DeclBitVector_Types::Idx i = getAnalysisData().getIdx(D); + return i.isValid() ? Live.getBit(i) : false; +} + +bool LiveVariables::isLive(const Stmt* Loc, const Stmt* StmtVal) const { + return getStmtData(Loc)(StmtVal,getAnalysisData()); +} + +bool LiveVariables::isLive(const Stmt* Loc, const VarDecl* D) const { + return getStmtData(Loc)(D,getAnalysisData()); +} + +//===----------------------------------------------------------------------===// +// printing liveness state for debugging +// + +void LiveVariables::dumpLiveness(const ValTy& V, const SourceManager& SM) const { + const AnalysisDataTy& AD = getAnalysisData(); + + for (AnalysisDataTy::decl_iterator I = AD.begin_decl(), + E = AD.end_decl(); I!=E; ++I) + if (V.getDeclBit(I->second)) { + llvm::errs() << " " << I->first->getIdentifier()->getName() << " <"; + I->first->getLocation().dump(SM); + llvm::errs() << ">\n"; + } +} + +void LiveVariables::dumpBlockLiveness(const SourceManager& M) const { + for (BlockDataMapTy::const_iterator I = getBlockDataMap().begin(), + E = getBlockDataMap().end(); I!=E; ++I) { + llvm::errs() << "\n[ B" << I->first->getBlockID() + << " (live variables at block exit) ]\n"; + dumpLiveness(I->second,M); + } + + llvm::errs() << "\n"; +} diff --git a/contrib/llvm/tools/clang/lib/Analysis/Makefile b/contrib/llvm/tools/clang/lib/Analysis/Makefile new file mode 100644 index 0000000..9b47380 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/Makefile @@ -0,0 +1,21 @@ +##===- clang/lib/Analysis/Makefile -------------------------*- Makefile -*-===## +# +# The LLVM Compiler Infrastructure +# +# This file is distributed under the University of Illinois Open Source +# License. See LICENSE.TXT for details. +# +##===----------------------------------------------------------------------===## +# +# This implements analyses built on top of source-level CFGs. +# +##===----------------------------------------------------------------------===## + +LEVEL = ../../../.. +LIBRARYNAME := clangAnalysis +BUILD_ARCHIVE = 1 + +CPP.Flags += -I$(PROJ_SRC_DIR)/../../include -I$(PROJ_OBJ_DIR)/../../include + +include $(LEVEL)/Makefile.common + diff --git a/contrib/llvm/tools/clang/lib/Analysis/PrintfFormatString.cpp b/contrib/llvm/tools/clang/lib/Analysis/PrintfFormatString.cpp new file mode 100644 index 0000000..c38aae3 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/PrintfFormatString.cpp @@ -0,0 +1,584 @@ +//= PrintfFormatStrings.cpp - Analysis of printf format strings --*- C++ -*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Handling of format string in printf and friends. The structure of format +// strings for fprintf() are described in C99 7.19.6.1. +// +//===----------------------------------------------------------------------===// + +#include "clang/Analysis/Analyses/PrintfFormatString.h" +#include "clang/AST/ASTContext.h" + +using clang::analyze_printf::ArgTypeResult; +using clang::analyze_printf::FormatSpecifier; +using clang::analyze_printf::FormatStringHandler; +using clang::analyze_printf::OptionalAmount; +using clang::analyze_printf::PositionContext; + +using namespace clang; + +namespace { +class FormatSpecifierResult { + FormatSpecifier FS; + const char *Start; + bool Stop; +public: + FormatSpecifierResult(bool stop = false) + : Start(0), Stop(stop) {} + FormatSpecifierResult(const char *start, + const FormatSpecifier &fs) + : FS(fs), Start(start), Stop(false) {} + + + const char *getStart() const { return Start; } + bool shouldStop() const { return Stop; } + bool hasValue() const { return Start != 0; } + const FormatSpecifier &getValue() const { + assert(hasValue()); + return FS; + } + const FormatSpecifier &getValue() { return FS; } +}; +} // end anonymous namespace + +template <typename T> +class UpdateOnReturn { + T &ValueToUpdate; + const T &ValueToCopy; +public: + UpdateOnReturn(T &valueToUpdate, const T &valueToCopy) + : ValueToUpdate(valueToUpdate), ValueToCopy(valueToCopy) {} + + ~UpdateOnReturn() { + ValueToUpdate = ValueToCopy; + } +}; + +//===----------------------------------------------------------------------===// +// Methods for parsing format strings. +//===----------------------------------------------------------------------===// + +static OptionalAmount ParseAmount(const char *&Beg, const char *E) { + const char *I = Beg; + UpdateOnReturn <const char*> UpdateBeg(Beg, I); + + unsigned accumulator = 0; + bool hasDigits = false; + + for ( ; I != E; ++I) { + char c = *I; + if (c >= '0' && c <= '9') { + hasDigits = true; + accumulator = (accumulator * 10) + (c - '0'); + continue; + } + + if (hasDigits) + return OptionalAmount(OptionalAmount::Constant, accumulator, Beg); + + break; + } + + return OptionalAmount(); +} + +static OptionalAmount ParseNonPositionAmount(const char *&Beg, const char *E, + unsigned &argIndex) { + if (*Beg == '*') { + ++Beg; + return OptionalAmount(OptionalAmount::Arg, argIndex++, Beg); + } + + return ParseAmount(Beg, E); +} + +static OptionalAmount ParsePositionAmount(FormatStringHandler &H, + const char *Start, + const char *&Beg, const char *E, + PositionContext p) { + if (*Beg == '*') { + const char *I = Beg + 1; + const OptionalAmount &Amt = ParseAmount(I, E); + + if (Amt.getHowSpecified() == OptionalAmount::NotSpecified) { + H.HandleInvalidPosition(Beg, I - Beg, p); + return OptionalAmount(false); + } + + if (I== E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return OptionalAmount(false); + } + + assert(Amt.getHowSpecified() == OptionalAmount::Constant); + + if (*I == '$') { + // Special case: '*0$', since this is an easy mistake. + if (Amt.getConstantAmount() == 0) { + H.HandleZeroPosition(Beg, I - Beg + 1); + return OptionalAmount(false); + } + + const char *Tmp = Beg; + Beg = ++I; + + return OptionalAmount(OptionalAmount::Arg, Amt.getConstantAmount() - 1, + Tmp); + } + + H.HandleInvalidPosition(Beg, I - Beg, p); + return OptionalAmount(false); + } + + return ParseAmount(Beg, E); +} + +static bool ParsePrecision(FormatStringHandler &H, FormatSpecifier &FS, + const char *Start, const char *&Beg, const char *E, + unsigned *argIndex) { + if (argIndex) { + FS.setPrecision(ParseNonPositionAmount(Beg, E, *argIndex)); + } + else { + const OptionalAmount Amt = ParsePositionAmount(H, Start, Beg, E, + analyze_printf::PrecisionPos); + if (Amt.isInvalid()) + return true; + FS.setPrecision(Amt); + } + return false; +} + +static bool ParseFieldWidth(FormatStringHandler &H, FormatSpecifier &FS, + const char *Start, const char *&Beg, const char *E, + unsigned *argIndex) { + // FIXME: Support negative field widths. + if (argIndex) { + FS.setFieldWidth(ParseNonPositionAmount(Beg, E, *argIndex)); + } + else { + const OptionalAmount Amt = ParsePositionAmount(H, Start, Beg, E, + analyze_printf::FieldWidthPos); + if (Amt.isInvalid()) + return true; + FS.setFieldWidth(Amt); + } + return false; +} + + +static bool ParseArgPosition(FormatStringHandler &H, + FormatSpecifier &FS, const char *Start, + const char *&Beg, const char *E) { + + using namespace clang::analyze_printf; + const char *I = Beg; + + const OptionalAmount &Amt = ParseAmount(I, E); + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + if (Amt.getHowSpecified() == OptionalAmount::Constant && *(I++) == '$') { + // Special case: '%0$', since this is an easy mistake. + if (Amt.getConstantAmount() == 0) { + H.HandleZeroPosition(Start, I - Start); + return true; + } + + FS.setArgIndex(Amt.getConstantAmount() - 1); + FS.setUsesPositionalArg(); + // Update the caller's pointer if we decided to consume + // these characters. + Beg = I; + return false; + } + + return false; +} + +static FormatSpecifierResult ParseFormatSpecifier(FormatStringHandler &H, + const char *&Beg, + const char *E, + unsigned &argIndex) { + + using namespace clang::analyze_printf; + + const char *I = Beg; + const char *Start = 0; + UpdateOnReturn <const char*> UpdateBeg(Beg, I); + + // Look for a '%' character that indicates the start of a format specifier. + for ( ; I != E ; ++I) { + char c = *I; + if (c == '\0') { + // Detect spurious null characters, which are likely errors. + H.HandleNullChar(I); + return true; + } + if (c == '%') { + Start = I++; // Record the start of the format specifier. + break; + } + } + + // No format specifier found? + if (!Start) + return false; + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + FormatSpecifier FS; + if (ParseArgPosition(H, FS, Start, I, E)) + return true; + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + // Look for flags (if any). + bool hasMore = true; + for ( ; I != E; ++I) { + switch (*I) { + default: hasMore = false; break; + case '-': FS.setIsLeftJustified(); break; + case '+': FS.setHasPlusPrefix(); break; + case ' ': FS.setHasSpacePrefix(); break; + case '#': FS.setHasAlternativeForm(); break; + case '0': FS.setHasLeadingZeros(); break; + } + if (!hasMore) + break; + } + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + // Look for the field width (if any). + if (ParseFieldWidth(H, FS, Start, I, E, + FS.usesPositionalArg() ? 0 : &argIndex)) + return true; + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + // Look for the precision (if any). + if (*I == '.') { + ++I; + if (I == E) { + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + if (ParsePrecision(H, FS, Start, I, E, + FS.usesPositionalArg() ? 0 : &argIndex)) + return true; + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + } + + // Look for the length modifier. + LengthModifier lm = None; + switch (*I) { + default: + break; + case 'h': + ++I; + lm = (I != E && *I == 'h') ? ++I, AsChar : AsShort; + break; + case 'l': + ++I; + lm = (I != E && *I == 'l') ? ++I, AsLongLong : AsLong; + break; + case 'j': lm = AsIntMax; ++I; break; + case 'z': lm = AsSizeT; ++I; break; + case 't': lm = AsPtrDiff; ++I; break; + case 'L': lm = AsLongDouble; ++I; break; + case 'q': lm = AsLongLong; ++I; break; + } + FS.setLengthModifier(lm); + + if (I == E) { + // No more characters left? + H.HandleIncompleteFormatSpecifier(Start, E - Start); + return true; + } + + if (*I == '\0') { + // Detect spurious null characters, which are likely errors. + H.HandleNullChar(I); + return true; + } + + // Finally, look for the conversion specifier. + const char *conversionPosition = I++; + ConversionSpecifier::Kind k = ConversionSpecifier::InvalidSpecifier; + switch (*conversionPosition) { + default: + break; + // C99: 7.19.6.1 (section 8). + case '%': k = ConversionSpecifier::PercentArg; break; + case 'A': k = ConversionSpecifier::AArg; break; + case 'E': k = ConversionSpecifier::EArg; break; + case 'F': k = ConversionSpecifier::FArg; break; + case 'G': k = ConversionSpecifier::GArg; break; + case 'X': k = ConversionSpecifier::XArg; break; + case 'a': k = ConversionSpecifier::aArg; break; + case 'c': k = ConversionSpecifier::IntAsCharArg; break; + case 'd': k = ConversionSpecifier::dArg; break; + case 'e': k = ConversionSpecifier::eArg; break; + case 'f': k = ConversionSpecifier::fArg; break; + case 'g': k = ConversionSpecifier::gArg; break; + case 'i': k = ConversionSpecifier::iArg; break; + case 'n': k = ConversionSpecifier::OutIntPtrArg; break; + case 'o': k = ConversionSpecifier::oArg; break; + case 'p': k = ConversionSpecifier::VoidPtrArg; break; + case 's': k = ConversionSpecifier::CStrArg; break; + case 'u': k = ConversionSpecifier::uArg; break; + case 'x': k = ConversionSpecifier::xArg; break; + // Mac OS X (unicode) specific + case 'C': k = ConversionSpecifier::CArg; break; + case 'S': k = ConversionSpecifier::UnicodeStrArg; break; + // Objective-C. + case '@': k = ConversionSpecifier::ObjCObjArg; break; + // Glibc specific. + case 'm': k = ConversionSpecifier::PrintErrno; break; + } + ConversionSpecifier CS(conversionPosition, k); + FS.setConversionSpecifier(CS); + if (CS.consumesDataArgument() && !FS.usesPositionalArg()) + FS.setArgIndex(argIndex++); + + if (k == ConversionSpecifier::InvalidSpecifier) { + // Assume the conversion takes one argument. + return !H.HandleInvalidConversionSpecifier(FS, Beg, I - Beg); + } + return FormatSpecifierResult(Start, FS); +} + +bool clang::analyze_printf::ParseFormatString(FormatStringHandler &H, + const char *I, const char *E) { + + unsigned argIndex = 0; + + // Keep looking for a format specifier until we have exhausted the string. + while (I != E) { + const FormatSpecifierResult &FSR = ParseFormatSpecifier(H, I, E, argIndex); + // Did a fail-stop error of any kind occur when parsing the specifier? + // If so, don't do any more processing. + if (FSR.shouldStop()) + return true;; + // Did we exhaust the string or encounter an error that + // we can recover from? + if (!FSR.hasValue()) + continue; + // We have a format specifier. Pass it to the callback. + if (!H.HandleFormatSpecifier(FSR.getValue(), FSR.getStart(), + I - FSR.getStart())) + return true; + } + assert(I == E && "Format string not exhausted"); + return false; +} + +FormatStringHandler::~FormatStringHandler() {} + +//===----------------------------------------------------------------------===// +// Methods on ArgTypeResult. +//===----------------------------------------------------------------------===// + +bool ArgTypeResult::matchesType(ASTContext &C, QualType argTy) const { + assert(isValid()); + + if (K == UnknownTy) + return true; + + if (K == SpecificTy) { + argTy = C.getCanonicalType(argTy).getUnqualifiedType(); + + if (T == argTy) + return true; + + if (const BuiltinType *BT = argTy->getAs<BuiltinType>()) + switch (BT->getKind()) { + default: + break; + case BuiltinType::Char_S: + case BuiltinType::SChar: + return T == C.UnsignedCharTy; + case BuiltinType::Char_U: + case BuiltinType::UChar: + return T == C.SignedCharTy; + case BuiltinType::Short: + return T == C.UnsignedShortTy; + case BuiltinType::UShort: + return T == C.ShortTy; + case BuiltinType::Int: + return T == C.UnsignedIntTy; + case BuiltinType::UInt: + return T == C.IntTy; + case BuiltinType::Long: + return T == C.UnsignedLongTy; + case BuiltinType::ULong: + return T == C.LongTy; + case BuiltinType::LongLong: + return T == C.UnsignedLongLongTy; + case BuiltinType::ULongLong: + return T == C.LongLongTy; + } + + return false; + } + + if (K == CStrTy) { + const PointerType *PT = argTy->getAs<PointerType>(); + if (!PT) + return false; + + QualType pointeeTy = PT->getPointeeType(); + + if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>()) + switch (BT->getKind()) { + case BuiltinType::Void: + case BuiltinType::Char_U: + case BuiltinType::UChar: + case BuiltinType::Char_S: + case BuiltinType::SChar: + return true; + default: + break; + } + + return false; + } + + if (K == WCStrTy) { + const PointerType *PT = argTy->getAs<PointerType>(); + if (!PT) + return false; + + QualType pointeeTy = + C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType(); + + return pointeeTy == C.getWCharType(); + } + + return false; +} + +QualType ArgTypeResult::getRepresentativeType(ASTContext &C) const { + assert(isValid()); + if (K == SpecificTy) + return T; + if (K == CStrTy) + return C.getPointerType(C.CharTy); + if (K == WCStrTy) + return C.getPointerType(C.getWCharType()); + if (K == ObjCPointerTy) + return C.ObjCBuiltinIdTy; + + return QualType(); +} + +//===----------------------------------------------------------------------===// +// Methods on OptionalAmount. +//===----------------------------------------------------------------------===// + +ArgTypeResult OptionalAmount::getArgType(ASTContext &Ctx) const { + return Ctx.IntTy; +} + +//===----------------------------------------------------------------------===// +// Methods on FormatSpecifier. +//===----------------------------------------------------------------------===// + +ArgTypeResult FormatSpecifier::getArgType(ASTContext &Ctx) const { + if (!CS.consumesDataArgument()) + return ArgTypeResult::Invalid(); + + if (CS.isIntArg()) + switch (LM) { + case AsLongDouble: + return ArgTypeResult::Invalid(); + case None: return Ctx.IntTy; + case AsChar: return Ctx.SignedCharTy; + case AsShort: return Ctx.ShortTy; + case AsLong: return Ctx.LongTy; + case AsLongLong: return Ctx.LongLongTy; + case AsIntMax: + // FIXME: Return unknown for now. + return ArgTypeResult(); + case AsSizeT: return Ctx.getSizeType(); + case AsPtrDiff: return Ctx.getPointerDiffType(); + } + + if (CS.isUIntArg()) + switch (LM) { + case AsLongDouble: + return ArgTypeResult::Invalid(); + case None: return Ctx.UnsignedIntTy; + case AsChar: return Ctx.UnsignedCharTy; + case AsShort: return Ctx.UnsignedShortTy; + case AsLong: return Ctx.UnsignedLongTy; + case AsLongLong: return Ctx.UnsignedLongLongTy; + case AsIntMax: + // FIXME: Return unknown for now. + return ArgTypeResult(); + case AsSizeT: + // FIXME: How to get the corresponding unsigned + // version of size_t? + return ArgTypeResult(); + case AsPtrDiff: + // FIXME: How to get the corresponding unsigned + // version of ptrdiff_t? + return ArgTypeResult(); + } + + if (CS.isDoubleArg()) { + if (LM == AsLongDouble) + return Ctx.LongDoubleTy; + return Ctx.DoubleTy; + } + + switch (CS.getKind()) { + case ConversionSpecifier::CStrArg: + return ArgTypeResult(LM == AsWideChar ? ArgTypeResult::WCStrTy : ArgTypeResult::CStrTy); + case ConversionSpecifier::UnicodeStrArg: + // FIXME: This appears to be Mac OS X specific. + return ArgTypeResult::WCStrTy; + case ConversionSpecifier::CArg: + return Ctx.WCharTy; + default: + break; + } + + // FIXME: Handle other cases. + return ArgTypeResult(); +} + diff --git a/contrib/llvm/tools/clang/lib/Analysis/ReachableCode.cpp b/contrib/llvm/tools/clang/lib/Analysis/ReachableCode.cpp new file mode 100644 index 0000000..f959e5c --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/ReachableCode.cpp @@ -0,0 +1,278 @@ +//=- ReachableCodePathInsensitive.cpp ---------------------------*- C++ --*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements a flow-sensitive, path-insensitive analysis of +// determining reachable blocks within a CFG. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/BitVector.h" +#include "llvm/ADT/SmallVector.h" +#include "clang/AST/Expr.h" +#include "clang/AST/ExprCXX.h" +#include "clang/AST/StmtCXX.h" +#include "clang/Analysis/Analyses/ReachableCode.h" +#include "clang/Analysis/CFG.h" +#include "clang/Analysis/AnalysisContext.h" +#include "clang/Basic/SourceManager.h" + +using namespace clang; + +static SourceLocation GetUnreachableLoc(const CFGBlock &b, SourceRange &R1, + SourceRange &R2) { + const Stmt *S = 0; + unsigned sn = 0; + R1 = R2 = SourceRange(); + +top: + if (sn < b.size()) + S = b[sn].getStmt(); + else if (b.getTerminator()) + S = b.getTerminator(); + else + return SourceLocation(); + + switch (S->getStmtClass()) { + case Expr::BinaryOperatorClass: { + const BinaryOperator *BO = cast<BinaryOperator>(S); + if (BO->getOpcode() == BinaryOperator::Comma) { + if (sn+1 < b.size()) + return b[sn+1].getStmt()->getLocStart(); + const CFGBlock *n = &b; + while (1) { + if (n->getTerminator()) + return n->getTerminator()->getLocStart(); + if (n->succ_size() != 1) + return SourceLocation(); + n = n[0].succ_begin()[0]; + if (n->pred_size() != 1) + return SourceLocation(); + if (!n->empty()) + return n[0][0].getStmt()->getLocStart(); + } + } + R1 = BO->getLHS()->getSourceRange(); + R2 = BO->getRHS()->getSourceRange(); + return BO->getOperatorLoc(); + } + case Expr::UnaryOperatorClass: { + const UnaryOperator *UO = cast<UnaryOperator>(S); + R1 = UO->getSubExpr()->getSourceRange(); + return UO->getOperatorLoc(); + } + case Expr::CompoundAssignOperatorClass: { + const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(S); + R1 = CAO->getLHS()->getSourceRange(); + R2 = CAO->getRHS()->getSourceRange(); + return CAO->getOperatorLoc(); + } + case Expr::ConditionalOperatorClass: { + const ConditionalOperator *CO = cast<ConditionalOperator>(S); + return CO->getQuestionLoc(); + } + case Expr::MemberExprClass: { + const MemberExpr *ME = cast<MemberExpr>(S); + R1 = ME->getSourceRange(); + return ME->getMemberLoc(); + } + case Expr::ArraySubscriptExprClass: { + const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(S); + R1 = ASE->getLHS()->getSourceRange(); + R2 = ASE->getRHS()->getSourceRange(); + return ASE->getRBracketLoc(); + } + case Expr::CStyleCastExprClass: { + const CStyleCastExpr *CSC = cast<CStyleCastExpr>(S); + R1 = CSC->getSubExpr()->getSourceRange(); + return CSC->getLParenLoc(); + } + case Expr::CXXFunctionalCastExprClass: { + const CXXFunctionalCastExpr *CE = cast <CXXFunctionalCastExpr>(S); + R1 = CE->getSubExpr()->getSourceRange(); + return CE->getTypeBeginLoc(); + } + case Expr::ImplicitCastExprClass: + ++sn; + goto top; + case Stmt::CXXTryStmtClass: { + return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc(); + } + default: ; + } + R1 = S->getSourceRange(); + return S->getLocStart(); +} + +static SourceLocation MarkLiveTop(const CFGBlock *Start, + llvm::BitVector &reachable, + SourceManager &SM) { + + // Prep work worklist. + llvm::SmallVector<const CFGBlock*, 32> WL; + WL.push_back(Start); + + SourceRange R1, R2; + SourceLocation top = GetUnreachableLoc(*Start, R1, R2); + + bool FromMainFile = false; + bool FromSystemHeader = false; + bool TopValid = false; + + if (top.isValid()) { + FromMainFile = SM.isFromMainFile(top); + FromSystemHeader = SM.isInSystemHeader(top); + TopValid = true; + } + + // Solve + while (!WL.empty()) { + const CFGBlock *item = WL.back(); + WL.pop_back(); + + SourceLocation c = GetUnreachableLoc(*item, R1, R2); + if (c.isValid() + && (!TopValid + || (SM.isFromMainFile(c) && !FromMainFile) + || (FromSystemHeader && !SM.isInSystemHeader(c)) + || SM.isBeforeInTranslationUnit(c, top))) { + top = c; + FromMainFile = SM.isFromMainFile(top); + FromSystemHeader = SM.isInSystemHeader(top); + } + + reachable.set(item->getBlockID()); + for (CFGBlock::const_succ_iterator I=item->succ_begin(), E=item->succ_end(); + I != E; ++I) + if (const CFGBlock *B = *I) { + unsigned blockID = B->getBlockID(); + if (!reachable[blockID]) { + reachable.set(blockID); + WL.push_back(B); + } + } + } + + return top; +} + +static int LineCmp(const void *p1, const void *p2) { + SourceLocation *Line1 = (SourceLocation *)p1; + SourceLocation *Line2 = (SourceLocation *)p2; + return !(*Line1 < *Line2); +} + +namespace { +struct ErrLoc { + SourceLocation Loc; + SourceRange R1; + SourceRange R2; + ErrLoc(SourceLocation l, SourceRange r1, SourceRange r2) + : Loc(l), R1(r1), R2(r2) { } +}; +} +namespace clang { namespace reachable_code { + +/// ScanReachableFromBlock - Mark all blocks reachable from Start. +/// Returns the total number of blocks that were marked reachable. +unsigned ScanReachableFromBlock(const CFGBlock &Start, + llvm::BitVector &Reachable) { + unsigned count = 0; + llvm::SmallVector<const CFGBlock*, 32> WL; + + // Prep work queue + Reachable.set(Start.getBlockID()); + ++count; + WL.push_back(&Start); + + // Find the reachable blocks from 'Start'. + while (!WL.empty()) { + const CFGBlock *item = WL.back(); + WL.pop_back(); + + // Look at the successors and mark then reachable. + for (CFGBlock::const_succ_iterator I=item->succ_begin(), E=item->succ_end(); + I != E; ++I) + if (const CFGBlock *B = *I) { + unsigned blockID = B->getBlockID(); + if (!Reachable[blockID]) { + Reachable.set(blockID); + ++count; + WL.push_back(B); + } + } + } + return count; +} + +void FindUnreachableCode(AnalysisContext &AC, Callback &CB) { + CFG *cfg = AC.getCFG(); + if (!cfg) + return; + + // Scan for reachable blocks. + llvm::BitVector reachable(cfg->getNumBlockIDs()); + unsigned numReachable = ScanReachableFromBlock(cfg->getEntry(), reachable); + + // If there are no unreachable blocks, we're done. + if (numReachable == cfg->getNumBlockIDs()) + return; + + SourceRange R1, R2; + + llvm::SmallVector<ErrLoc, 24> lines; + bool AddEHEdges = AC.getAddEHEdges(); + + // First, give warnings for blocks with no predecessors, as they + // can't be part of a loop. + for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) { + CFGBlock &b = **I; + if (!reachable[b.getBlockID()]) { + if (b.pred_empty()) { + if (!AddEHEdges && dyn_cast_or_null<CXXTryStmt>(b.getTerminator())) { + // When not adding EH edges from calls, catch clauses + // can otherwise seem dead. Avoid noting them as dead. + numReachable += ScanReachableFromBlock(b, reachable); + continue; + } + SourceLocation c = GetUnreachableLoc(b, R1, R2); + if (!c.isValid()) { + // Blocks without a location can't produce a warning, so don't mark + // reachable blocks from here as live. + reachable.set(b.getBlockID()); + ++numReachable; + continue; + } + lines.push_back(ErrLoc(c, R1, R2)); + // Avoid excessive errors by marking everything reachable from here + numReachable += ScanReachableFromBlock(b, reachable); + } + } + } + + if (numReachable < cfg->getNumBlockIDs()) { + // And then give warnings for the tops of loops. + for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) { + CFGBlock &b = **I; + if (!reachable[b.getBlockID()]) + // Avoid excessive errors by marking everything reachable from here + lines.push_back(ErrLoc(MarkLiveTop(&b, reachable, + AC.getASTContext().getSourceManager()), + SourceRange(), SourceRange())); + } + } + + llvm::array_pod_sort(lines.begin(), lines.end(), LineCmp); + + for (llvm::SmallVectorImpl<ErrLoc>::iterator I=lines.begin(), E=lines.end(); + I != E; ++I) + if (I->Loc.isValid()) + CB.HandleUnreachable(I->Loc, I->R1, I->R2); +} + +}} // end namespace clang::reachable_code diff --git a/contrib/llvm/tools/clang/lib/Analysis/UninitializedValues.cpp b/contrib/llvm/tools/clang/lib/Analysis/UninitializedValues.cpp new file mode 100644 index 0000000..7a62864 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/UninitializedValues.cpp @@ -0,0 +1,314 @@ +//==- UninitializedValues.cpp - Find Uninitialized Values -------*- C++ --*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements Uninitialized Values analysis for source-level CFGs. +// +//===----------------------------------------------------------------------===// + +#include "clang/Analysis/Analyses/UninitializedValues.h" +#include "clang/Analysis/Visitors/CFGRecStmtDeclVisitor.h" +#include "clang/Analysis/AnalysisDiagnostic.h" +#include "clang/AST/ASTContext.h" +#include "clang/Analysis/FlowSensitive/DataflowSolver.h" + +#include "llvm/ADT/SmallPtrSet.h" + +using namespace clang; + +//===----------------------------------------------------------------------===// +// Dataflow initialization logic. +//===----------------------------------------------------------------------===// + +namespace { + +class RegisterDecls + : public CFGRecStmtDeclVisitor<RegisterDecls> { + + UninitializedValues::AnalysisDataTy& AD; +public: + RegisterDecls(UninitializedValues::AnalysisDataTy& ad) : AD(ad) {} + + void VisitVarDecl(VarDecl* VD) { AD.Register(VD); } + CFG& getCFG() { return AD.getCFG(); } +}; + +} // end anonymous namespace + +void UninitializedValues::InitializeValues(const CFG& cfg) { + RegisterDecls R(getAnalysisData()); + cfg.VisitBlockStmts(R); +} + +//===----------------------------------------------------------------------===// +// Transfer functions. +//===----------------------------------------------------------------------===// + +namespace { +class TransferFuncs + : public CFGStmtVisitor<TransferFuncs,bool> { + + UninitializedValues::ValTy V; + UninitializedValues::AnalysisDataTy& AD; +public: + TransferFuncs(UninitializedValues::AnalysisDataTy& ad) : AD(ad) {} + + UninitializedValues::ValTy& getVal() { return V; } + CFG& getCFG() { return AD.getCFG(); } + + void SetTopValue(UninitializedValues::ValTy& X) { + X.setDeclValues(AD); + X.resetBlkExprValues(AD); + } + + bool VisitDeclRefExpr(DeclRefExpr* DR); + bool VisitBinaryOperator(BinaryOperator* B); + bool VisitUnaryOperator(UnaryOperator* U); + bool VisitStmt(Stmt* S); + bool VisitCallExpr(CallExpr* C); + bool VisitDeclStmt(DeclStmt* D); + bool VisitConditionalOperator(ConditionalOperator* C); + bool BlockStmt_VisitObjCForCollectionStmt(ObjCForCollectionStmt* S); + + bool Visit(Stmt *S); + bool BlockStmt_VisitExpr(Expr* E); + + void VisitTerminator(CFGBlock* B) { } +}; + +static const bool Initialized = false; +static const bool Uninitialized = true; + +bool TransferFuncs::VisitDeclRefExpr(DeclRefExpr* DR) { + + if (VarDecl* VD = dyn_cast<VarDecl>(DR->getDecl())) + if (VD->isBlockVarDecl()) { + + if (AD.Observer) + AD.Observer->ObserveDeclRefExpr(V, AD, DR, VD); + + // Pseudo-hack to prevent cascade of warnings. If an accessed variable + // is uninitialized, then we are already going to flag a warning for + // this variable, which a "source" of uninitialized values. + // We can otherwise do a full "taint" of uninitialized values. The + // client has both options by toggling AD.FullUninitTaint. + + if (AD.FullUninitTaint) + return V(VD,AD); + } + + return Initialized; +} + +static VarDecl* FindBlockVarDecl(Expr* E) { + + // Blast through casts and parentheses to find any DeclRefExprs that + // refer to a block VarDecl. + + if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(E->IgnoreParenCasts())) + if (VarDecl* VD = dyn_cast<VarDecl>(DR->getDecl())) + if (VD->isBlockVarDecl()) return VD; + + return NULL; +} + +bool TransferFuncs::VisitBinaryOperator(BinaryOperator* B) { + + if (VarDecl* VD = FindBlockVarDecl(B->getLHS())) + if (B->isAssignmentOp()) { + if (B->getOpcode() == BinaryOperator::Assign) + return V(VD,AD) = Visit(B->getRHS()); + else // Handle +=, -=, *=, etc. We do want '&', not '&&'. + return V(VD,AD) = Visit(B->getLHS()) & Visit(B->getRHS()); + } + + return VisitStmt(B); +} + +bool TransferFuncs::VisitDeclStmt(DeclStmt* S) { + for (DeclStmt::decl_iterator I=S->decl_begin(), E=S->decl_end(); I!=E; ++I) { + VarDecl *VD = dyn_cast<VarDecl>(*I); + if (VD && VD->isBlockVarDecl()) { + if (Stmt* I = VD->getInit()) { + // Visit the subexpression to check for uses of uninitialized values, + // even if we don't propagate that value. + bool isSubExprUninit = Visit(I); + V(VD,AD) = AD.FullUninitTaint ? isSubExprUninit : Initialized; + } + else { + // Special case for declarations of array types. For things like: + // + // char x[10]; + // + // we should treat "x" as being initialized, because the variable + // "x" really refers to the memory block. Clearly x[1] is + // uninitialized, but expressions like "(char *) x" really do refer to + // an initialized value. This simple dataflow analysis does not reason + // about the contents of arrays, although it could be potentially + // extended to do so if the array were of constant size. + if (VD->getType()->isArrayType()) + V(VD,AD) = Initialized; + else + V(VD,AD) = Uninitialized; + } + } + } + return Uninitialized; // Value is never consumed. +} + +bool TransferFuncs::VisitCallExpr(CallExpr* C) { + VisitChildren(C); + return Initialized; +} + +bool TransferFuncs::VisitUnaryOperator(UnaryOperator* U) { + switch (U->getOpcode()) { + case UnaryOperator::AddrOf: { + VarDecl* VD = FindBlockVarDecl(U->getSubExpr()); + if (VD && VD->isBlockVarDecl()) + return V(VD,AD) = Initialized; + break; + } + + default: + break; + } + + return Visit(U->getSubExpr()); +} + +bool +TransferFuncs::BlockStmt_VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { + // This represents a use of the 'collection' + bool x = Visit(S->getCollection()); + + if (x == Uninitialized) + return Uninitialized; + + // This represents an initialization of the 'element' value. + Stmt* Element = S->getElement(); + VarDecl* VD = 0; + + if (DeclStmt* DS = dyn_cast<DeclStmt>(Element)) + VD = cast<VarDecl>(DS->getSingleDecl()); + else { + Expr* ElemExpr = cast<Expr>(Element)->IgnoreParens(); + + // Initialize the value of the reference variable. + if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(ElemExpr)) + VD = cast<VarDecl>(DR->getDecl()); + else + return Visit(ElemExpr); + } + + V(VD,AD) = Initialized; + return Initialized; +} + + +bool TransferFuncs::VisitConditionalOperator(ConditionalOperator* C) { + Visit(C->getCond()); + + bool rhsResult = Visit(C->getRHS()); + // Handle the GNU extension for missing LHS. + if (Expr *lhs = C->getLHS()) + return Visit(lhs) & rhsResult; // Yes: we want &, not &&. + else + return rhsResult; +} + +bool TransferFuncs::VisitStmt(Stmt* S) { + bool x = Initialized; + + // We don't stop at the first subexpression that is Uninitialized because + // evaluating some subexpressions may result in propogating "Uninitialized" + // or "Initialized" to variables referenced in the other subexpressions. + for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) + if (*I && Visit(*I) == Uninitialized) x = Uninitialized; + + return x; +} + +bool TransferFuncs::Visit(Stmt *S) { + if (AD.isTracked(static_cast<Expr*>(S))) return V(static_cast<Expr*>(S),AD); + else return static_cast<CFGStmtVisitor<TransferFuncs,bool>*>(this)->Visit(S); +} + +bool TransferFuncs::BlockStmt_VisitExpr(Expr* E) { + bool x = static_cast<CFGStmtVisitor<TransferFuncs,bool>*>(this)->Visit(E); + if (AD.isTracked(E)) V(E,AD) = x; + return x; +} + +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// Merge operator. +// +// In our transfer functions we take the approach that any +// combination of uninitialized values, e.g. +// Uninitialized + ___ = Uninitialized. +// +// Merges take the same approach, preferring soundness. At a confluence point, +// if any predecessor has a variable marked uninitialized, the value is +// uninitialized at the confluence point. +//===----------------------------------------------------------------------===// + +namespace { + typedef StmtDeclBitVector_Types::Union Merge; + typedef DataflowSolver<UninitializedValues,TransferFuncs,Merge> Solver; +} + +//===----------------------------------------------------------------------===// +// Uninitialized values checker. Scan an AST and flag variable uses +//===----------------------------------------------------------------------===// + +UninitializedValues_ValueTypes::ObserverTy::~ObserverTy() {} + +namespace { +class UninitializedValuesChecker + : public UninitializedValues::ObserverTy { + + ASTContext &Ctx; + Diagnostic &Diags; + llvm::SmallPtrSet<VarDecl*,10> AlreadyWarned; + +public: + UninitializedValuesChecker(ASTContext &ctx, Diagnostic &diags) + : Ctx(ctx), Diags(diags) {} + + virtual void ObserveDeclRefExpr(UninitializedValues::ValTy& V, + UninitializedValues::AnalysisDataTy& AD, + DeclRefExpr* DR, VarDecl* VD) { + + assert ( AD.isTracked(VD) && "Unknown VarDecl."); + + if (V(VD,AD) == Uninitialized) + if (AlreadyWarned.insert(VD)) + Diags.Report(Ctx.getFullLoc(DR->getSourceRange().getBegin()), + diag::warn_uninit_val); + } +}; +} // end anonymous namespace + +namespace clang { +void CheckUninitializedValues(CFG& cfg, ASTContext &Ctx, Diagnostic &Diags, + bool FullUninitTaint) { + + // Compute the uninitialized values information. + UninitializedValues U(cfg); + U.getAnalysisData().FullUninitTaint = FullUninitTaint; + Solver S(U); + S.runOnCFG(cfg); + + // Scan for DeclRefExprs that use uninitialized values. + UninitializedValuesChecker Observer(Ctx,Diags); + U.getAnalysisData().Observer = &Observer; + S.runOnAllBlocks(cfg); +} +} // end namespace clang |
