| //=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- 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 analysis_warnings::[Policy,Executor]. |
| // Together they are used by Sema to issue warnings based on inexpensive |
| // static analysis algorithms in libAnalysis. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Sema/AnalysisBasedWarnings.h" |
| #include "clang/Sema/SemaInternal.h" |
| #include "clang/Sema/ScopeInfo.h" |
| #include "clang/Basic/SourceManager.h" |
| #include "clang/Basic/SourceLocation.h" |
| #include "clang/Lex/Preprocessor.h" |
| #include "clang/AST/DeclObjC.h" |
| #include "clang/AST/DeclCXX.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/AST/StmtObjC.h" |
| #include "clang/AST/StmtCXX.h" |
| #include "clang/AST/EvaluatedExprVisitor.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/Analysis/AnalysisContext.h" |
| #include "clang/Analysis/CFG.h" |
| #include "clang/Analysis/Analyses/ReachableCode.h" |
| #include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h" |
| #include "clang/Analysis/Analyses/ThreadSafety.h" |
| #include "clang/Analysis/CFGStmtMap.h" |
| #include "clang/Analysis/Analyses/UninitializedValues.h" |
| #include "llvm/ADT/BitVector.h" |
| #include "llvm/ADT/FoldingSet.h" |
| #include "llvm/ADT/ImmutableMap.h" |
| #include "llvm/ADT/PostOrderIterator.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/Support/Casting.h" |
| #include <algorithm> |
| #include <vector> |
| |
| using namespace clang; |
| |
| //===----------------------------------------------------------------------===// |
| // Unreachable code analysis. |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class UnreachableCodeHandler : public reachable_code::Callback { |
| Sema &S; |
| public: |
| UnreachableCodeHandler(Sema &s) : S(s) {} |
| |
| void HandleUnreachable(SourceLocation L, SourceRange R1, SourceRange R2) { |
| S.Diag(L, diag::warn_unreachable) << R1 << R2; |
| } |
| }; |
| } |
| |
| /// CheckUnreachable - Check for unreachable code. |
| static void CheckUnreachable(Sema &S, AnalysisContext &AC) { |
| UnreachableCodeHandler UC(S); |
| reachable_code::FindUnreachableCode(AC, UC); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Check for missing return value. |
| //===----------------------------------------------------------------------===// |
| |
| enum ControlFlowKind { |
| UnknownFallThrough, |
| NeverFallThrough, |
| MaybeFallThrough, |
| AlwaysFallThrough, |
| NeverFallThroughOrReturn |
| }; |
| |
| /// CheckFallThrough - Check that we don't fall off the end of a |
| /// Statement that should return a value. |
| /// |
| /// \returns AlwaysFallThrough iff we always fall off the end of the statement, |
| /// MaybeFallThrough iff we might or might not fall off the end, |
| /// NeverFallThroughOrReturn iff we never fall off the end of the statement or |
| /// return. We assume NeverFallThrough iff we never fall off the end of the |
| /// statement but we may return. We assume that functions not marked noreturn |
| /// will return. |
| static ControlFlowKind CheckFallThrough(AnalysisContext &AC) { |
| CFG *cfg = AC.getCFG(); |
| if (cfg == 0) return UnknownFallThrough; |
| |
| // The CFG leaves in dead things, and we don't want the dead code paths to |
| // confuse us, so we mark all live things first. |
| llvm::BitVector live(cfg->getNumBlockIDs()); |
| unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(), |
| live); |
| |
| bool AddEHEdges = AC.getAddEHEdges(); |
| if (!AddEHEdges && count != cfg->getNumBlockIDs()) |
| // When there are things remaining dead, and we didn't add EH edges |
| // from CallExprs to the catch clauses, we have to go back and |
| // mark them as live. |
| for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) { |
| CFGBlock &b = **I; |
| if (!live[b.getBlockID()]) { |
| if (b.pred_begin() == b.pred_end()) { |
| if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator())) |
| // When not adding EH edges from calls, catch clauses |
| // can otherwise seem dead. Avoid noting them as dead. |
| count += reachable_code::ScanReachableFromBlock(&b, live); |
| continue; |
| } |
| } |
| } |
| |
| // Now we know what is live, we check the live precessors of the exit block |
| // and look for fall through paths, being careful to ignore normal returns, |
| // and exceptional paths. |
| bool HasLiveReturn = false; |
| bool HasFakeEdge = false; |
| bool HasPlainEdge = false; |
| bool HasAbnormalEdge = false; |
| |
| // Ignore default cases that aren't likely to be reachable because all |
| // enums in a switch(X) have explicit case statements. |
| CFGBlock::FilterOptions FO; |
| FO.IgnoreDefaultsWithCoveredEnums = 1; |
| |
| for (CFGBlock::filtered_pred_iterator |
| I = cfg->getExit().filtered_pred_start_end(FO); I.hasMore(); ++I) { |
| const CFGBlock& B = **I; |
| if (!live[B.getBlockID()]) |
| continue; |
| |
| // Skip blocks which contain an element marked as no-return. They don't |
| // represent actually viable edges into the exit block, so mark them as |
| // abnormal. |
| if (B.hasNoReturnElement()) { |
| HasAbnormalEdge = true; |
| continue; |
| } |
| |
| // Destructors can appear after the 'return' in the CFG. This is |
| // normal. We need to look pass the destructors for the return |
| // statement (if it exists). |
| CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend(); |
| |
| for ( ; ri != re ; ++ri) |
| if (isa<CFGStmt>(*ri)) |
| break; |
| |
| // No more CFGElements in the block? |
| if (ri == re) { |
| if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) { |
| HasAbnormalEdge = true; |
| continue; |
| } |
| // A labeled empty statement, or the entry block... |
| HasPlainEdge = true; |
| continue; |
| } |
| |
| CFGStmt CS = cast<CFGStmt>(*ri); |
| const Stmt *S = CS.getStmt(); |
| if (isa<ReturnStmt>(S)) { |
| HasLiveReturn = true; |
| continue; |
| } |
| if (isa<ObjCAtThrowStmt>(S)) { |
| HasFakeEdge = true; |
| continue; |
| } |
| if (isa<CXXThrowExpr>(S)) { |
| HasFakeEdge = true; |
| continue; |
| } |
| if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) { |
| if (AS->isMSAsm()) { |
| HasFakeEdge = true; |
| HasLiveReturn = true; |
| continue; |
| } |
| } |
| if (isa<CXXTryStmt>(S)) { |
| HasAbnormalEdge = true; |
| continue; |
| } |
| if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit()) |
| == B.succ_end()) { |
| HasAbnormalEdge = true; |
| continue; |
| } |
| |
| HasPlainEdge = true; |
| } |
| if (!HasPlainEdge) { |
| if (HasLiveReturn) |
| return NeverFallThrough; |
| return NeverFallThroughOrReturn; |
| } |
| if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn) |
| return MaybeFallThrough; |
| // This says AlwaysFallThrough for calls to functions that are not marked |
| // noreturn, that don't return. If people would like this warning to be more |
| // accurate, such functions should be marked as noreturn. |
| return AlwaysFallThrough; |
| } |
| |
| namespace { |
| |
| struct CheckFallThroughDiagnostics { |
| unsigned diag_MaybeFallThrough_HasNoReturn; |
| unsigned diag_MaybeFallThrough_ReturnsNonVoid; |
| unsigned diag_AlwaysFallThrough_HasNoReturn; |
| unsigned diag_AlwaysFallThrough_ReturnsNonVoid; |
| unsigned diag_NeverFallThroughOrReturn; |
| bool funMode; |
| SourceLocation FuncLoc; |
| |
| static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) { |
| CheckFallThroughDiagnostics D; |
| D.FuncLoc = Func->getLocation(); |
| D.diag_MaybeFallThrough_HasNoReturn = |
| diag::warn_falloff_noreturn_function; |
| D.diag_MaybeFallThrough_ReturnsNonVoid = |
| diag::warn_maybe_falloff_nonvoid_function; |
| D.diag_AlwaysFallThrough_HasNoReturn = |
| diag::warn_falloff_noreturn_function; |
| D.diag_AlwaysFallThrough_ReturnsNonVoid = |
| diag::warn_falloff_nonvoid_function; |
| |
| // Don't suggest that virtual functions be marked "noreturn", since they |
| // might be overridden by non-noreturn functions. |
| bool isVirtualMethod = false; |
| if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func)) |
| isVirtualMethod = Method->isVirtual(); |
| |
| // Don't suggest that template instantiations be marked "noreturn" |
| bool isTemplateInstantiation = false; |
| if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func)) { |
| switch (Function->getTemplateSpecializationKind()) { |
| case TSK_Undeclared: |
| case TSK_ExplicitSpecialization: |
| break; |
| |
| case TSK_ImplicitInstantiation: |
| case TSK_ExplicitInstantiationDeclaration: |
| case TSK_ExplicitInstantiationDefinition: |
| isTemplateInstantiation = true; |
| break; |
| } |
| } |
| |
| if (!isVirtualMethod && !isTemplateInstantiation) |
| D.diag_NeverFallThroughOrReturn = |
| diag::warn_suggest_noreturn_function; |
| else |
| D.diag_NeverFallThroughOrReturn = 0; |
| |
| D.funMode = true; |
| return D; |
| } |
| |
| static CheckFallThroughDiagnostics MakeForBlock() { |
| CheckFallThroughDiagnostics D; |
| D.diag_MaybeFallThrough_HasNoReturn = |
| diag::err_noreturn_block_has_return_expr; |
| D.diag_MaybeFallThrough_ReturnsNonVoid = |
| diag::err_maybe_falloff_nonvoid_block; |
| D.diag_AlwaysFallThrough_HasNoReturn = |
| diag::err_noreturn_block_has_return_expr; |
| D.diag_AlwaysFallThrough_ReturnsNonVoid = |
| diag::err_falloff_nonvoid_block; |
| D.diag_NeverFallThroughOrReturn = |
| diag::warn_suggest_noreturn_block; |
| D.funMode = false; |
| return D; |
| } |
| |
| bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid, |
| bool HasNoReturn) const { |
| if (funMode) { |
| return (ReturnsVoid || |
| D.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function, |
| FuncLoc) == DiagnosticsEngine::Ignored) |
| && (!HasNoReturn || |
| D.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr, |
| FuncLoc) == DiagnosticsEngine::Ignored) |
| && (!ReturnsVoid || |
| D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc) |
| == DiagnosticsEngine::Ignored); |
| } |
| |
| // For blocks. |
| return ReturnsVoid && !HasNoReturn |
| && (!ReturnsVoid || |
| D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc) |
| == DiagnosticsEngine::Ignored); |
| } |
| }; |
| |
| } |
| |
| /// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a |
| /// function that should return a value. Check that we don't fall off the end |
| /// of a noreturn function. We assume that functions and blocks not marked |
| /// noreturn will return. |
| static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body, |
| const BlockExpr *blkExpr, |
| const CheckFallThroughDiagnostics& CD, |
| AnalysisContext &AC) { |
| |
| bool ReturnsVoid = false; |
| bool HasNoReturn = false; |
| |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { |
| ReturnsVoid = FD->getResultType()->isVoidType(); |
| HasNoReturn = FD->hasAttr<NoReturnAttr>() || |
| FD->getType()->getAs<FunctionType>()->getNoReturnAttr(); |
| } |
| else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { |
| ReturnsVoid = MD->getResultType()->isVoidType(); |
| HasNoReturn = MD->hasAttr<NoReturnAttr>(); |
| } |
| else if (isa<BlockDecl>(D)) { |
| QualType BlockTy = blkExpr->getType(); |
| if (const FunctionType *FT = |
| BlockTy->getPointeeType()->getAs<FunctionType>()) { |
| if (FT->getResultType()->isVoidType()) |
| ReturnsVoid = true; |
| if (FT->getNoReturnAttr()) |
| HasNoReturn = true; |
| } |
| } |
| |
| DiagnosticsEngine &Diags = S.getDiagnostics(); |
| |
| // Short circuit for compilation speed. |
| if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn)) |
| return; |
| |
| // FIXME: Function try block |
| if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) { |
| switch (CheckFallThrough(AC)) { |
| case UnknownFallThrough: |
| break; |
| |
| case MaybeFallThrough: |
| if (HasNoReturn) |
| S.Diag(Compound->getRBracLoc(), |
| CD.diag_MaybeFallThrough_HasNoReturn); |
| else if (!ReturnsVoid) |
| S.Diag(Compound->getRBracLoc(), |
| CD.diag_MaybeFallThrough_ReturnsNonVoid); |
| break; |
| case AlwaysFallThrough: |
| if (HasNoReturn) |
| S.Diag(Compound->getRBracLoc(), |
| CD.diag_AlwaysFallThrough_HasNoReturn); |
| else if (!ReturnsVoid) |
| S.Diag(Compound->getRBracLoc(), |
| CD.diag_AlwaysFallThrough_ReturnsNonVoid); |
| break; |
| case NeverFallThroughOrReturn: |
| if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) { |
| if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { |
| S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn) |
| << 0 << FD; |
| } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { |
| S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn) |
| << 1 << MD; |
| } else { |
| S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn); |
| } |
| } |
| break; |
| case NeverFallThrough: |
| break; |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // -Wuninitialized |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| /// ContainsReference - A visitor class to search for references to |
| /// a particular declaration (the needle) within any evaluated component of an |
| /// expression (recursively). |
| class ContainsReference : public EvaluatedExprVisitor<ContainsReference> { |
| bool FoundReference; |
| const DeclRefExpr *Needle; |
| |
| public: |
| ContainsReference(ASTContext &Context, const DeclRefExpr *Needle) |
| : EvaluatedExprVisitor<ContainsReference>(Context), |
| FoundReference(false), Needle(Needle) {} |
| |
| void VisitExpr(Expr *E) { |
| // Stop evaluating if we already have a reference. |
| if (FoundReference) |
| return; |
| |
| EvaluatedExprVisitor<ContainsReference>::VisitExpr(E); |
| } |
| |
| void VisitDeclRefExpr(DeclRefExpr *E) { |
| if (E == Needle) |
| FoundReference = true; |
| else |
| EvaluatedExprVisitor<ContainsReference>::VisitDeclRefExpr(E); |
| } |
| |
| bool doesContainReference() const { return FoundReference; } |
| }; |
| } |
| |
| static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) { |
| // Don't issue a fixit if there is already an initializer. |
| if (VD->getInit()) |
| return false; |
| |
| // Suggest possible initialization (if any). |
| const char *initialization = 0; |
| QualType VariableTy = VD->getType().getCanonicalType(); |
| |
| if (VariableTy->isObjCObjectPointerType() || |
| VariableTy->isBlockPointerType()) { |
| // Check if 'nil' is defined. |
| if (S.PP.getMacroInfo(&S.getASTContext().Idents.get("nil"))) |
| initialization = " = nil"; |
| else |
| initialization = " = 0"; |
| } |
| else if (VariableTy->isRealFloatingType()) |
| initialization = " = 0.0"; |
| else if (VariableTy->isBooleanType() && S.Context.getLangOptions().CPlusPlus) |
| initialization = " = false"; |
| else if (VariableTy->isEnumeralType()) |
| return false; |
| else if (VariableTy->isPointerType() || VariableTy->isMemberPointerType()) { |
| if (S.Context.getLangOptions().CPlusPlus0x) |
| initialization = " = nullptr"; |
| // Check if 'NULL' is defined. |
| else if (S.PP.getMacroInfo(&S.getASTContext().Idents.get("NULL"))) |
| initialization = " = NULL"; |
| else |
| initialization = " = 0"; |
| } |
| else if (VariableTy->isScalarType()) |
| initialization = " = 0"; |
| |
| if (initialization) { |
| SourceLocation loc = S.PP.getLocForEndOfToken(VD->getLocEnd()); |
| S.Diag(loc, diag::note_var_fixit_add_initialization) << VD->getDeclName() |
| << FixItHint::CreateInsertion(loc, initialization); |
| return true; |
| } |
| return false; |
| } |
| |
| /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an |
| /// uninitialized variable. This manages the different forms of diagnostic |
| /// emitted for particular types of uses. Returns true if the use was diagnosed |
| /// as a warning. If a pariticular use is one we omit warnings for, returns |
| /// false. |
| static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD, |
| const Expr *E, bool isAlwaysUninit, |
| bool alwaysReportSelfInit = false) { |
| bool isSelfInit = false; |
| |
| if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { |
| if (isAlwaysUninit) { |
| // Inspect the initializer of the variable declaration which is |
| // being referenced prior to its initialization. We emit |
| // specialized diagnostics for self-initialization, and we |
| // specifically avoid warning about self references which take the |
| // form of: |
| // |
| // int x = x; |
| // |
| // This is used to indicate to GCC that 'x' is intentionally left |
| // uninitialized. Proven code paths which access 'x' in |
| // an uninitialized state after this will still warn. |
| // |
| // TODO: Should we suppress maybe-uninitialized warnings for |
| // variables initialized in this way? |
| if (const Expr *Initializer = VD->getInit()) { |
| if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts()) |
| return false; |
| |
| ContainsReference CR(S.Context, DRE); |
| CR.Visit(const_cast<Expr*>(Initializer)); |
| isSelfInit = CR.doesContainReference(); |
| } |
| if (isSelfInit) { |
| S.Diag(DRE->getLocStart(), |
| diag::warn_uninit_self_reference_in_init) |
| << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange(); |
| } else { |
| S.Diag(DRE->getLocStart(), diag::warn_uninit_var) |
| << VD->getDeclName() << DRE->getSourceRange(); |
| } |
| } else { |
| S.Diag(DRE->getLocStart(), diag::warn_maybe_uninit_var) |
| << VD->getDeclName() << DRE->getSourceRange(); |
| } |
| } else { |
| const BlockExpr *BE = cast<BlockExpr>(E); |
| S.Diag(BE->getLocStart(), |
| isAlwaysUninit ? diag::warn_uninit_var_captured_by_block |
| : diag::warn_maybe_uninit_var_captured_by_block) |
| << VD->getDeclName(); |
| } |
| |
| // Report where the variable was declared when the use wasn't within |
| // the initializer of that declaration & we didn't already suggest |
| // an initialization fixit. |
| if (!isSelfInit && !SuggestInitializationFixit(S, VD)) |
| S.Diag(VD->getLocStart(), diag::note_uninit_var_def) |
| << VD->getDeclName(); |
| |
| return true; |
| } |
| |
| typedef std::pair<const Expr*, bool> UninitUse; |
| |
| namespace { |
| struct SLocSort { |
| bool operator()(const UninitUse &a, const UninitUse &b) { |
| SourceLocation aLoc = a.first->getLocStart(); |
| SourceLocation bLoc = b.first->getLocStart(); |
| return aLoc.getRawEncoding() < bLoc.getRawEncoding(); |
| } |
| }; |
| |
| class UninitValsDiagReporter : public UninitVariablesHandler { |
| Sema &S; |
| typedef SmallVector<UninitUse, 2> UsesVec; |
| typedef llvm::DenseMap<const VarDecl *, std::pair<UsesVec*, bool> > UsesMap; |
| UsesMap *uses; |
| |
| public: |
| UninitValsDiagReporter(Sema &S) : S(S), uses(0) {} |
| ~UninitValsDiagReporter() { |
| flushDiagnostics(); |
| } |
| |
| std::pair<UsesVec*, bool> &getUses(const VarDecl *vd) { |
| if (!uses) |
| uses = new UsesMap(); |
| |
| UsesMap::mapped_type &V = (*uses)[vd]; |
| UsesVec *&vec = V.first; |
| if (!vec) |
| vec = new UsesVec(); |
| |
| return V; |
| } |
| |
| void handleUseOfUninitVariable(const Expr *ex, const VarDecl *vd, |
| bool isAlwaysUninit) { |
| getUses(vd).first->push_back(std::make_pair(ex, isAlwaysUninit)); |
| } |
| |
| void handleSelfInit(const VarDecl *vd) { |
| getUses(vd).second = true; |
| } |
| |
| void flushDiagnostics() { |
| if (!uses) |
| return; |
| |
| for (UsesMap::iterator i = uses->begin(), e = uses->end(); i != e; ++i) { |
| const VarDecl *vd = i->first; |
| const UsesMap::mapped_type &V = i->second; |
| |
| UsesVec *vec = V.first; |
| bool hasSelfInit = V.second; |
| |
| // Specially handle the case where we have uses of an uninitialized |
| // variable, but the root cause is an idiomatic self-init. We want |
| // to report the diagnostic at the self-init since that is the root cause. |
| if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec)) |
| DiagnoseUninitializedUse(S, vd, vd->getInit()->IgnoreParenCasts(), |
| /* isAlwaysUninit */ true, |
| /* alwaysReportSelfInit */ true); |
| else { |
| // Sort the uses by their SourceLocations. While not strictly |
| // guaranteed to produce them in line/column order, this will provide |
| // a stable ordering. |
| std::sort(vec->begin(), vec->end(), SLocSort()); |
| |
| for (UsesVec::iterator vi = vec->begin(), ve = vec->end(); vi != ve; |
| ++vi) { |
| if (DiagnoseUninitializedUse(S, vd, vi->first, |
| /*isAlwaysUninit=*/vi->second)) |
| // Skip further diagnostics for this variable. We try to warn only |
| // on the first point at which a variable is used uninitialized. |
| break; |
| } |
| } |
| |
| // Release the uses vector. |
| delete vec; |
| } |
| delete uses; |
| } |
| |
| private: |
| static bool hasAlwaysUninitializedUse(const UsesVec* vec) { |
| for (UsesVec::const_iterator i = vec->begin(), e = vec->end(); i != e; ++i) { |
| if (i->second) { |
| return true; |
| } |
| } |
| return false; |
| } |
| }; |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // -Wthread-safety |
| //===----------------------------------------------------------------------===// |
| namespace clang { |
| namespace thread_safety { |
| typedef std::pair<SourceLocation, PartialDiagnostic> DelayedDiag; |
| typedef llvm::SmallVector<DelayedDiag, 4> DiagList; |
| |
| struct SortDiagBySourceLocation { |
| Sema &S; |
| SortDiagBySourceLocation(Sema &S) : S(S) {} |
| |
| bool operator()(const DelayedDiag &left, const DelayedDiag &right) { |
| // Although this call will be slow, this is only called when outputting |
| // multiple warnings. |
| return S.getSourceManager().isBeforeInTranslationUnit(left.first, |
| right.first); |
| } |
| }; |
| |
| class ThreadSafetyReporter : public clang::thread_safety::ThreadSafetyHandler { |
| Sema &S; |
| DiagList Warnings; |
| SourceLocation FunLocation; |
| |
| // Helper functions |
| void warnLockMismatch(unsigned DiagID, Name LockName, SourceLocation Loc) { |
| // Gracefully handle rare cases when the analysis can't get a more |
| // precise source location. |
| if (!Loc.isValid()) |
| Loc = FunLocation; |
| PartialDiagnostic Warning = S.PDiag(DiagID) << LockName; |
| Warnings.push_back(DelayedDiag(Loc, Warning)); |
| } |
| |
| public: |
| ThreadSafetyReporter(Sema &S, SourceLocation FL) |
| : S(S), FunLocation(FL) {} |
| |
| /// \brief Emit all buffered diagnostics in order of sourcelocation. |
| /// We need to output diagnostics produced while iterating through |
| /// the lockset in deterministic order, so this function orders diagnostics |
| /// and outputs them. |
| void emitDiagnostics() { |
| SortDiagBySourceLocation SortDiagBySL(S); |
| sort(Warnings.begin(), Warnings.end(), SortDiagBySL); |
| for (DiagList::iterator I = Warnings.begin(), E = Warnings.end(); |
| I != E; ++I) |
| S.Diag(I->first, I->second); |
| } |
| |
| void handleInvalidLockExp(SourceLocation Loc) { |
| PartialDiagnostic Warning = S.PDiag(diag::warn_cannot_resolve_lock) << Loc; |
| Warnings.push_back(DelayedDiag(Loc, Warning)); |
| } |
| void handleUnmatchedUnlock(Name LockName, SourceLocation Loc) { |
| warnLockMismatch(diag::warn_unlock_but_no_lock, LockName, Loc); |
| } |
| |
| void handleDoubleLock(Name LockName, SourceLocation Loc) { |
| warnLockMismatch(diag::warn_double_lock, LockName, Loc); |
| } |
| |
| void handleMutexHeldEndOfScope(Name LockName, SourceLocation Loc, |
| LockErrorKind LEK){ |
| unsigned DiagID = 0; |
| switch (LEK) { |
| case LEK_LockedSomePredecessors: |
| DiagID = diag::warn_lock_at_end_of_scope; |
| break; |
| case LEK_LockedSomeLoopIterations: |
| DiagID = diag::warn_expecting_lock_held_on_loop; |
| break; |
| case LEK_LockedAtEndOfFunction: |
| DiagID = diag::warn_no_unlock; |
| break; |
| } |
| warnLockMismatch(DiagID, LockName, Loc); |
| } |
| |
| |
| void handleExclusiveAndShared(Name LockName, SourceLocation Loc1, |
| SourceLocation Loc2) { |
| PartialDiagnostic Warning = |
| S.PDiag(diag::warn_lock_exclusive_and_shared) << LockName; |
| PartialDiagnostic Note = |
| S.PDiag(diag::note_lock_exclusive_and_shared) << LockName; |
| Warnings.push_back(DelayedDiag(Loc1, Warning)); |
| Warnings.push_back(DelayedDiag(Loc2, Note)); |
| } |
| |
| void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK, |
| AccessKind AK, SourceLocation Loc) { |
| assert((POK == POK_VarAccess || POK == POK_VarDereference) |
| && "Only works for variables"); |
| unsigned DiagID = POK == POK_VarAccess? |
| diag::warn_variable_requires_any_lock: |
| diag::warn_var_deref_requires_any_lock; |
| PartialDiagnostic Warning = S.PDiag(DiagID) |
| << D->getName() << getLockKindFromAccessKind(AK); |
| Warnings.push_back(DelayedDiag(Loc, Warning)); |
| } |
| |
| void handleMutexNotHeld(const NamedDecl *D, ProtectedOperationKind POK, |
| Name LockName, LockKind LK, SourceLocation Loc) { |
| unsigned DiagID = 0; |
| switch (POK) { |
| case POK_VarAccess: |
| DiagID = diag::warn_variable_requires_lock; |
| break; |
| case POK_VarDereference: |
| DiagID = diag::warn_var_deref_requires_lock; |
| break; |
| case POK_FunctionCall: |
| DiagID = diag::warn_fun_requires_lock; |
| break; |
| } |
| PartialDiagnostic Warning = S.PDiag(DiagID) |
| << D->getName() << LockName << LK; |
| Warnings.push_back(DelayedDiag(Loc, Warning)); |
| } |
| |
| void handleFunExcludesLock(Name FunName, Name LockName, SourceLocation Loc) { |
| PartialDiagnostic Warning = |
| S.PDiag(diag::warn_fun_excludes_mutex) << FunName << LockName; |
| Warnings.push_back(DelayedDiag(Loc, Warning)); |
| } |
| }; |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based |
| // warnings on a function, method, or block. |
| //===----------------------------------------------------------------------===// |
| |
| clang::sema::AnalysisBasedWarnings::Policy::Policy() { |
| enableCheckFallThrough = 1; |
| enableCheckUnreachable = 0; |
| enableThreadSafetyAnalysis = 0; |
| } |
| |
| clang::sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s) |
| : S(s), |
| NumFunctionsAnalyzed(0), |
| NumFunctionsWithBadCFGs(0), |
| NumCFGBlocks(0), |
| MaxCFGBlocksPerFunction(0), |
| NumUninitAnalysisFunctions(0), |
| NumUninitAnalysisVariables(0), |
| MaxUninitAnalysisVariablesPerFunction(0), |
| NumUninitAnalysisBlockVisits(0), |
| MaxUninitAnalysisBlockVisitsPerFunction(0) { |
| DiagnosticsEngine &D = S.getDiagnostics(); |
| DefaultPolicy.enableCheckUnreachable = (unsigned) |
| (D.getDiagnosticLevel(diag::warn_unreachable, SourceLocation()) != |
| DiagnosticsEngine::Ignored); |
| DefaultPolicy.enableThreadSafetyAnalysis = (unsigned) |
| (D.getDiagnosticLevel(diag::warn_double_lock, SourceLocation()) != |
| DiagnosticsEngine::Ignored); |
| |
| } |
| |
| static void flushDiagnostics(Sema &S, sema::FunctionScopeInfo *fscope) { |
| for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator |
| i = fscope->PossiblyUnreachableDiags.begin(), |
| e = fscope->PossiblyUnreachableDiags.end(); |
| i != e; ++i) { |
| const sema::PossiblyUnreachableDiag &D = *i; |
| S.Diag(D.Loc, D.PD); |
| } |
| } |
| |
| void clang::sema:: |
| AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P, |
| sema::FunctionScopeInfo *fscope, |
| const Decl *D, const BlockExpr *blkExpr) { |
| |
| // We avoid doing analysis-based warnings when there are errors for |
| // two reasons: |
| // (1) The CFGs often can't be constructed (if the body is invalid), so |
| // don't bother trying. |
| // (2) The code already has problems; running the analysis just takes more |
| // time. |
| DiagnosticsEngine &Diags = S.getDiagnostics(); |
| |
| // Do not do any analysis for declarations in system headers if we are |
| // going to just ignore them. |
| if (Diags.getSuppressSystemWarnings() && |
| S.SourceMgr.isInSystemHeader(D->getLocation())) |
| return; |
| |
| // For code in dependent contexts, we'll do this at instantiation time. |
| if (cast<DeclContext>(D)->isDependentContext()) |
| return; |
| |
| if (Diags.hasErrorOccurred() || Diags.hasFatalErrorOccurred()) { |
| // Flush out any possibly unreachable diagnostics. |
| flushDiagnostics(S, fscope); |
| return; |
| } |
| |
| const Stmt *Body = D->getBody(); |
| assert(Body); |
| |
| AnalysisContext AC(D, 0); |
| |
| // Don't generate EH edges for CallExprs as we'd like to avoid the n^2 |
| // explosion for destrutors that can result and the compile time hit. |
| AC.getCFGBuildOptions().PruneTriviallyFalseEdges = true; |
| AC.getCFGBuildOptions().AddEHEdges = false; |
| AC.getCFGBuildOptions().AddInitializers = true; |
| AC.getCFGBuildOptions().AddImplicitDtors = true; |
| |
| // Force that certain expressions appear as CFGElements in the CFG. This |
| // is used to speed up various analyses. |
| // FIXME: This isn't the right factoring. This is here for initial |
| // prototyping, but we need a way for analyses to say what expressions they |
| // expect to always be CFGElements and then fill in the BuildOptions |
| // appropriately. This is essentially a layering violation. |
| if (P.enableCheckUnreachable) { |
| // Unreachable code analysis requires a linearized CFG. |
| AC.getCFGBuildOptions().setAllAlwaysAdd(); |
| } |
| else { |
| AC.getCFGBuildOptions() |
| .setAlwaysAdd(Stmt::BinaryOperatorClass) |
| .setAlwaysAdd(Stmt::BlockExprClass) |
| .setAlwaysAdd(Stmt::CStyleCastExprClass) |
| .setAlwaysAdd(Stmt::DeclRefExprClass) |
| .setAlwaysAdd(Stmt::ImplicitCastExprClass) |
| .setAlwaysAdd(Stmt::UnaryOperatorClass); |
| } |
| |
| // Construct the analysis context with the specified CFG build options. |
| |
| // Emit delayed diagnostics. |
| if (!fscope->PossiblyUnreachableDiags.empty()) { |
| bool analyzed = false; |
| |
| // Register the expressions with the CFGBuilder. |
| for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator |
| i = fscope->PossiblyUnreachableDiags.begin(), |
| e = fscope->PossiblyUnreachableDiags.end(); |
| i != e; ++i) { |
| if (const Stmt *stmt = i->stmt) |
| AC.registerForcedBlockExpression(stmt); |
| } |
| |
| if (AC.getCFG()) { |
| analyzed = true; |
| for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator |
| i = fscope->PossiblyUnreachableDiags.begin(), |
| e = fscope->PossiblyUnreachableDiags.end(); |
| i != e; ++i) |
| { |
| const sema::PossiblyUnreachableDiag &D = *i; |
| bool processed = false; |
| if (const Stmt *stmt = i->stmt) { |
| const CFGBlock *block = AC.getBlockForRegisteredExpression(stmt); |
| assert(block); |
| if (CFGReverseBlockReachabilityAnalysis *cra = AC.getCFGReachablityAnalysis()) { |
| // Can this block be reached from the entrance? |
| if (cra->isReachable(&AC.getCFG()->getEntry(), block)) |
| S.Diag(D.Loc, D.PD); |
| processed = true; |
| } |
| } |
| if (!processed) { |
| // Emit the warning anyway if we cannot map to a basic block. |
| S.Diag(D.Loc, D.PD); |
| } |
| } |
| } |
| |
| if (!analyzed) |
| flushDiagnostics(S, fscope); |
| } |
| |
| |
| // Warning: check missing 'return' |
| if (P.enableCheckFallThrough) { |
| const CheckFallThroughDiagnostics &CD = |
| (isa<BlockDecl>(D) ? CheckFallThroughDiagnostics::MakeForBlock() |
| : CheckFallThroughDiagnostics::MakeForFunction(D)); |
| CheckFallThroughForBody(S, D, Body, blkExpr, CD, AC); |
| } |
| |
| // Warning: check for unreachable code |
| if (P.enableCheckUnreachable) |
| CheckUnreachable(S, AC); |
| |
| // Check for thread safety violations |
| if (P.enableThreadSafetyAnalysis) { |
| SourceLocation FL = AC.getDecl()->getLocation(); |
| thread_safety::ThreadSafetyReporter Reporter(S, FL); |
| thread_safety::runThreadSafetyAnalysis(AC, Reporter); |
| Reporter.emitDiagnostics(); |
| } |
| |
| if (Diags.getDiagnosticLevel(diag::warn_uninit_var, D->getLocStart()) |
| != DiagnosticsEngine::Ignored || |
| Diags.getDiagnosticLevel(diag::warn_maybe_uninit_var, D->getLocStart()) |
| != DiagnosticsEngine::Ignored) { |
| if (CFG *cfg = AC.getCFG()) { |
| UninitValsDiagReporter reporter(S); |
| UninitVariablesAnalysisStats stats; |
| std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats)); |
| runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC, |
| reporter, stats); |
| |
| if (S.CollectStats && stats.NumVariablesAnalyzed > 0) { |
| ++NumUninitAnalysisFunctions; |
| NumUninitAnalysisVariables += stats.NumVariablesAnalyzed; |
| NumUninitAnalysisBlockVisits += stats.NumBlockVisits; |
| MaxUninitAnalysisVariablesPerFunction = |
| std::max(MaxUninitAnalysisVariablesPerFunction, |
| stats.NumVariablesAnalyzed); |
| MaxUninitAnalysisBlockVisitsPerFunction = |
| std::max(MaxUninitAnalysisBlockVisitsPerFunction, |
| stats.NumBlockVisits); |
| } |
| } |
| } |
| |
| // Collect statistics about the CFG if it was built. |
| if (S.CollectStats && AC.isCFGBuilt()) { |
| ++NumFunctionsAnalyzed; |
| if (CFG *cfg = AC.getCFG()) { |
| // If we successfully built a CFG for this context, record some more |
| // detail information about it. |
| NumCFGBlocks += cfg->getNumBlockIDs(); |
| MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction, |
| cfg->getNumBlockIDs()); |
| } else { |
| ++NumFunctionsWithBadCFGs; |
| } |
| } |
| } |
| |
| void clang::sema::AnalysisBasedWarnings::PrintStats() const { |
| llvm::errs() << "\n*** Analysis Based Warnings Stats:\n"; |
| |
| unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs; |
| unsigned AvgCFGBlocksPerFunction = |
| !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt; |
| llvm::errs() << NumFunctionsAnalyzed << " functions analyzed (" |
| << NumFunctionsWithBadCFGs << " w/o CFGs).\n" |
| << " " << NumCFGBlocks << " CFG blocks built.\n" |
| << " " << AvgCFGBlocksPerFunction |
| << " average CFG blocks per function.\n" |
| << " " << MaxCFGBlocksPerFunction |
| << " max CFG blocks per function.\n"; |
| |
| unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0 |
| : NumUninitAnalysisVariables/NumUninitAnalysisFunctions; |
| unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0 |
| : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions; |
| llvm::errs() << NumUninitAnalysisFunctions |
| << " functions analyzed for uninitialiazed variables\n" |
| << " " << NumUninitAnalysisVariables << " variables analyzed.\n" |
| << " " << AvgUninitVariablesPerFunction |
| << " average variables per function.\n" |
| << " " << MaxUninitAnalysisVariablesPerFunction |
| << " max variables per function.\n" |
| << " " << NumUninitAnalysisBlockVisits << " block visits.\n" |
| << " " << AvgUninitBlockVisitsPerFunction |
| << " average block visits per function.\n" |
| << " " << MaxUninitAnalysisBlockVisitsPerFunction |
| << " max block visits per function.\n"; |
| } |