13d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek//=- ReachableCodePathInsensitive.cpp ---------------------------*- C++ --*-==// 23d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// 33d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// The LLVM Compiler Infrastructure 43d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// 53d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// This file is distributed under the University of Illinois Open Source 63d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// License. See LICENSE.TXT for details. 73d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// 83d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek//===----------------------------------------------------------------------===// 93d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// 103d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// This file implements a flow-sensitive, path-insensitive analysis of 113d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// determining reachable blocks within a CFG. 123d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek// 133d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek//===----------------------------------------------------------------------===// 143d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek 1555fc873017f10f6f566b182b70f6fc22aefa3464Chandler Carruth#include "clang/Analysis/Analyses/ReachableCode.h" 1672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek#include "clang/AST/Expr.h" 1772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek#include "clang/AST/ExprCXX.h" 18f85e193739c953358c865005855253af4f68a497John McCall#include "clang/AST/ExprObjC.h" 19651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines#include "clang/AST/ParentMap.h" 200e2c34f92f00628d48968dfea096d36381f494cbStephen Hines#include "clang/AST/StmtCXX.h" 2172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek#include "clang/Analysis/AnalysisContext.h" 2255fc873017f10f6f566b182b70f6fc22aefa3464Chandler Carruth#include "clang/Analysis/CFG.h" 2372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek#include "clang/Basic/SourceManager.h" 240e2c34f92f00628d48968dfea096d36381f494cbStephen Hines#include "clang/Lex/Preprocessor.h" 2555fc873017f10f6f566b182b70f6fc22aefa3464Chandler Carruth#include "llvm/ADT/BitVector.h" 2655fc873017f10f6f566b182b70f6fc22aefa3464Chandler Carruth#include "llvm/ADT/SmallVector.h" 273d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek 283d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenekusing namespace clang; 293d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek 30651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 31651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines// Core Reachability Analysis routines. 32651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 33651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 34651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isEnumConstant(const Expr *Ex) { 35651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Ex); 36651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!DR) 37651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 38651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isa<EnumConstantDecl>(DR->getDecl()); 39651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 40651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 41651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isTrivialExpression(const Expr *Ex) { 42651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Ex = Ex->IgnoreParenCasts(); 43651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isa<IntegerLiteral>(Ex) || isa<StringLiteral>(Ex) || 44651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isa<CXXBoolLiteralExpr>(Ex) || isa<ObjCBoolLiteralExpr>(Ex) || 45651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isa<CharacterLiteral>(Ex) || 46651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isEnumConstant(Ex); 47651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 48651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 49651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isTrivialDoWhile(const CFGBlock *B, const Stmt *S) { 50651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Check if the block ends with a do...while() and see if 'S' is the 51651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // condition. 52651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const Stmt *Term = B->getTerminator()) { 53651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const DoStmt *DS = dyn_cast<DoStmt>(Term)) { 54651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Expr *Cond = DS->getCond()->IgnoreParenCasts(); 55651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return Cond == S && isTrivialExpression(Cond); 56651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 57651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 58651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 59651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 60651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 61651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isDeadReturn(const CFGBlock *B, const Stmt *S) { 626bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // Look to see if the current control flow ends with a 'return', and see if 636bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // 'S' is a substatement. The 'return' may not be the last element in the 646bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // block, or may be in a subsequent block because of destructors. 656bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines const CFGBlock *Current = B; 666bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines while (true) { 676bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines for (CFGBlock::const_reverse_iterator I = Current->rbegin(), 686bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines E = Current->rend(); 696bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines I != E; ++I) { 706bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) { 716bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(CS->getStmt())) { 726bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (RS == S) 73651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return true; 746bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (const Expr *RE = RS->getRetValue()) { 756bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines RE = RE->IgnoreParenCasts(); 766bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (RE == S) 776bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return true; 786bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines ParentMap PM(const_cast<Expr *>(RE)); 796bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // If 'S' is in the ParentMap, it is a subexpression of 806bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // the return statement. 816bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return PM.getParent(S); 826bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines } 83651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 846bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines break; 85651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 866bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines } 876bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // Note also that we are restricting the search for the return statement 886bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // to stop at control-flow; only part of a return statement may be dead, 896bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // without the whole return statement being dead. 906bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (Current->getTerminator().isTemporaryDtorsBranch()) { 916bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // Temporary destructors have a predictable control flow, thus we want to 926bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // look into the next block for the return statement. 936bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // We look into the false branch, as we know the true branch only contains 946bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // the call to the destructor. 956bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines assert(Current->succ_size() == 2); 966bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines Current = *(Current->succ_begin() + 1); 976bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines } else if (!Current->getTerminator() && Current->succ_size() == 1) { 986bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // If there is only one successor, we're not dealing with outgoing control 996bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // flow. Thus, look into the next block. 1006bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines Current = *Current->succ_begin(); 1016bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (Current->pred_size() > 1) { 1026bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // If there is more than one predecessor, we're dealing with incoming 1036bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // control flow - if the return statement is in that block, it might 1046bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // well be reachable via a different control flow, thus it's not dead. 1056bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return false; 1066bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines } 1076bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines } else { 1086bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines // We hit control flow or a dead end. Stop searching. 1096bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return false; 110651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 111651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 1126bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines llvm_unreachable("Broke out of infinite loop."); 113651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 114651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 115651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic SourceLocation getTopMostMacro(SourceLocation Loc, SourceManager &SM) { 116651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines assert(Loc.isMacroID()); 117651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceLocation Last; 118651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines while (Loc.isMacroID()) { 119651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Last = Loc; 120651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Loc = SM.getImmediateMacroCallerLoc(Loc); 121651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 122651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return Last; 123651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 124651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 125651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// Returns true if the statement is expanded from a configuration macro. 126651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isExpandedFromConfigurationMacro(const Stmt *S, 127651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor &PP, 128651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool IgnoreYES_NO = false) { 129651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // FIXME: This is not very precise. Here we just check to see if the 130651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // value comes from a macro, but we can do much better. This is likely 131651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // to be over conservative. This logic is factored into a separate function 132651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // so that we can refine it later. 133651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceLocation L = S->getLocStart(); 134651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (L.isMacroID()) { 135651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (IgnoreYES_NO) { 136651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // The Objective-C constant 'YES' and 'NO' 137651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // are defined as macros. Do not treat them 138651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // as configuration values. 139651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceManager &SM = PP.getSourceManager(); 140651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceLocation TopL = getTopMostMacro(L, SM); 141651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines StringRef MacroName = PP.getImmediateMacroName(TopL); 142651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (MacroName == "YES" || MacroName == "NO") 143651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 144651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 145651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return true; 146651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 147651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 148651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 149651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 150651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isConfigurationValue(const ValueDecl *D, Preprocessor &PP); 151651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 152651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// Returns true if the statement represents a configuration value. 153651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// 154651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// A configuration value is something usually determined at compile-time 155651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// to conditionally always execute some branch. Such guards are for 156651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// "sometimes unreachable" code. Such code is usually not interesting 157651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// to report as unreachable, and may mask truly unreachable code within 158651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// those blocks. 159651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isConfigurationValue(const Stmt *S, 160651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor &PP, 161651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceRange *SilenceableCondVal = nullptr, 162651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool IncludeIntegers = true, 163651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool WrappedInParens = false) { 164651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!S) 165651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 166651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 1676bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines if (const Expr *Ex = dyn_cast<Expr>(S)) 1686bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines S = Ex->IgnoreCasts(); 1696bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines 170651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Special case looking for the sigil '()' around an integer literal. 171651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const ParenExpr *PE = dyn_cast<ParenExpr>(S)) 172651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!PE->getLocStart().isMacroID()) 173651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(PE->getSubExpr(), PP, SilenceableCondVal, 174651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IncludeIntegers, true); 175651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 176651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const Expr *Ex = dyn_cast<Expr>(S)) 1776bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines S = Ex->IgnoreCasts(); 178651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 179651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool IgnoreYES_NO = false; 180651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 181651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines switch (S->getStmtClass()) { 182651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::CallExprClass: { 183651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const FunctionDecl *Callee = 184651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines dyn_cast_or_null<FunctionDecl>(cast<CallExpr>(S)->getCalleeDecl()); 185651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return Callee ? Callee->isConstexpr() : false; 186651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 187651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::DeclRefExprClass: 188651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(cast<DeclRefExpr>(S)->getDecl(), PP); 189651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::ObjCBoolLiteralExprClass: 190651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IgnoreYES_NO = true; 191651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Fallthrough. 192651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::CXXBoolLiteralExprClass: 193651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::IntegerLiteralClass: { 194651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Expr *E = cast<Expr>(S); 195651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (IncludeIntegers) { 196651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (SilenceableCondVal && !SilenceableCondVal->getBegin().isValid()) 197651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines *SilenceableCondVal = E->getSourceRange(); 198651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return WrappedInParens || isExpandedFromConfigurationMacro(E, PP, IgnoreYES_NO); 199651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 200651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 201651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 202651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::MemberExprClass: 203651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(cast<MemberExpr>(S)->getMemberDecl(), PP); 204651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::UnaryExprOrTypeTraitExprClass: 205651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return true; 206651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::BinaryOperatorClass: { 207651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const BinaryOperator *B = cast<BinaryOperator>(S); 208651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Only include raw integers (not enums) as configuration 209651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // values if they are used in a logical or comparison operator 210651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // (not arithmetic). 211651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IncludeIntegers &= (B->isLogicalOp() || B->isComparisonOp()); 212651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(B->getLHS(), PP, SilenceableCondVal, 213651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IncludeIntegers) || 214651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isConfigurationValue(B->getRHS(), PP, SilenceableCondVal, 215651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IncludeIntegers); 216651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 217651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines case Stmt::UnaryOperatorClass: { 218651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const UnaryOperator *UO = cast<UnaryOperator>(S); 219651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (SilenceableCondVal) 220651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines *SilenceableCondVal = UO->getSourceRange(); 221651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return UO->getOpcode() == UO_LNot && 222651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isConfigurationValue(UO->getSubExpr(), PP, SilenceableCondVal, 223651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines IncludeIntegers, WrappedInParens); 224651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 225651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines default: 226651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 227651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 228651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 229651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 230651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool isConfigurationValue(const ValueDecl *D, Preprocessor &PP) { 231651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) 232651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(ED->getInitExpr(), PP); 233651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const VarDecl *VD = dyn_cast<VarDecl>(D)) { 234651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // As a heuristic, treat globals as configuration values. Note 235651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // that we only will get here if Sema evaluated this 236651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // condition to a constant expression, which means the global 237651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // had to be declared in a way to be a truly constant value. 238651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // We could generalize this to local variables, but it isn't 239651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // clear if those truly represent configuration values that 240651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // gate unreachable code. 241651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!VD->hasLocalStorage()) 242651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return true; 243651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 244651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // As a heuristic, locals that have been marked 'const' explicitly 245651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // can be treated as configuration values as well. 246651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return VD->getType().isLocalConstQualified(); 247651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 248651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return false; 249651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 250651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 251651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines/// Returns true if we should always explore all successors of a block. 252651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic bool shouldTreatSuccessorsAsReachable(const CFGBlock *B, 253651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor &PP) { 254651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const Stmt *Term = B->getTerminator()) { 255651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (isa<SwitchStmt>(Term)) 256651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return true; 257651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Specially handle '||' and '&&'. 258651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (isa<BinaryOperator>(Term)) { 259651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(Term, PP); 260651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 261651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 262651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 263651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *Cond = B->getTerminatorCondition(/* stripParens */ false); 264651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return isConfigurationValue(Cond, PP); 265651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 266651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 267651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic unsigned scanFromBlock(const CFGBlock *Start, 268651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines llvm::BitVector &Reachable, 269651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor *PP, 270651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool IncludeSometimesUnreachableEdges) { 271651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines unsigned count = 0; 2720f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 273651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Prep work queue 274651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SmallVector<const CFGBlock*, 32> WL; 2750f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 276651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // The entry block may have already been marked reachable 277651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // by the caller. 278651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!Reachable[Start->getBlockID()]) { 279651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines ++count; 280651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Reachable[Start->getBlockID()] = true; 281651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 2820f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 283651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines WL.push_back(Start); 2840f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 285651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Find the reachable blocks from 'Start'. 286651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines while (!WL.empty()) { 287651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const CFGBlock *item = WL.pop_back_val(); 288651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 289651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // There are cases where we want to treat all successors as reachable. 290651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // The idea is that some "sometimes unreachable" code is not interesting, 291651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // and that we should forge ahead and explore those branches anyway. 292651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // This allows us to potentially uncover some "always unreachable" code 293651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // within the "sometimes unreachable" code. 294651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Look at the successors and mark then reachable. 295651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Optional<bool> TreatAllSuccessorsAsReachable; 296651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!IncludeSometimesUnreachableEdges) 297651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines TreatAllSuccessorsAsReachable = false; 298651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 299651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines for (CFGBlock::const_succ_iterator I = item->succ_begin(), 300651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines E = item->succ_end(); I != E; ++I) { 301651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const CFGBlock *B = *I; 302651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!B) do { 303651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const CFGBlock *UB = I->getPossiblyUnreachableBlock(); 304651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!UB) 305651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines break; 306651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 307651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!TreatAllSuccessorsAsReachable.hasValue()) { 308651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines assert(PP); 309651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines TreatAllSuccessorsAsReachable = 310651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines shouldTreatSuccessorsAsReachable(item, *PP); 311651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 312651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 313651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (TreatAllSuccessorsAsReachable.getValue()) { 314651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines B = UB; 315651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines break; 316651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 317651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 318651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines while (false); 319651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 320651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (B) { 321651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines unsigned blockID = B->getBlockID(); 322651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!Reachable[blockID]) { 323651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Reachable.set(blockID); 324651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines WL.push_back(B); 325651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines ++count; 326651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 327651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 328651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 329651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 330651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return count; 331651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 332651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 333651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesstatic unsigned scanMaybeReachableFromBlock(const CFGBlock *Start, 334651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor &PP, 335651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines llvm::BitVector &Reachable) { 336651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return scanFromBlock(Start, Reachable, &PP, true); 337651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines} 338651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 339651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 340651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines// Dead Code Scanner. 341651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 342651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 343651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesnamespace { 344651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines class DeadCodeScan { 345651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines llvm::BitVector Visited; 346651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines llvm::BitVector &Reachable; 347651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SmallVector<const CFGBlock *, 10> WorkList; 348651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Preprocessor &PP; 349651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 350651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines typedef SmallVector<std::pair<const CFGBlock *, const Stmt *>, 12> 351651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines DeferredLocsTy; 352651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 353651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines DeferredLocsTy DeferredLocs; 354651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 355651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines public: 356651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines DeadCodeScan(llvm::BitVector &reachable, Preprocessor &PP) 357651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines : Visited(reachable.size()), 358651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Reachable(reachable), 359651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines PP(PP) {} 360651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 361651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines void enqueue(const CFGBlock *block); 362651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines unsigned scanBackwards(const CFGBlock *Start, 363651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines clang::reachable_code::Callback &CB); 364651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 365651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines bool isDeadCodeRoot(const CFGBlock *Block); 366651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 367651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *findDeadCode(const CFGBlock *Block); 368651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 369651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines void reportDeadCode(const CFGBlock *B, 370651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *S, 371651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines clang::reachable_code::Callback &CB); 372651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines }; 3730f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 3740f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 375651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesvoid DeadCodeScan::enqueue(const CFGBlock *block) { 3760f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek unsigned blockID = block->getBlockID(); 3770f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (Reachable[blockID] || Visited[blockID]) 3780f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return; 3790f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek Visited[blockID] = true; 3800f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek WorkList.push_back(block); 3810f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 3820f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 3830f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekbool DeadCodeScan::isDeadCodeRoot(const clang::CFGBlock *Block) { 3840f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek bool isDeadRoot = true; 385651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 3860f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (CFGBlock::const_pred_iterator I = Block->pred_begin(), 387651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines E = Block->pred_end(); I != E; ++I) { 3880f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (const CFGBlock *PredBlock = *I) { 3890f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek unsigned blockID = PredBlock->getBlockID(); 3900f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (Visited[blockID]) { 3910f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek isDeadRoot = false; 3920f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 3930f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 3940f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (!Reachable[blockID]) { 3950f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek isDeadRoot = false; 3960f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek Visited[blockID] = true; 3970f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek WorkList.push_back(PredBlock); 3980f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 3990f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4000f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4010f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 402651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 4030f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return isDeadRoot; 4040f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 4050f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4060f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekstatic bool isValidDeadStmt(const Stmt *S) { 407e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek if (S->getLocStart().isInvalid()) 4080f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return false; 409e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) 4100f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return BO->getOpcode() != BO_Comma; 4110f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return true; 4120f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 4130f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4140f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekconst Stmt *DeadCodeScan::findDeadCode(const clang::CFGBlock *Block) { 4150f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (CFGBlock::const_iterator I = Block->begin(), E = Block->end(); I!=E; ++I) 416b07805485c603be3d8011f72611465324c9e664bDavid Blaikie if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) { 417b07805485c603be3d8011f72611465324c9e664bDavid Blaikie const Stmt *S = CS->getStmt(); 4180f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (isValidDeadStmt(S)) 4190f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return S; 4200f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 421651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 4220f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (CFGTerminator T = Block->getTerminator()) { 423651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (!T.isTemporaryDtorsBranch()) { 424651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *S = T.getStmt(); 425651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (isValidDeadStmt(S)) 426651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return S; 427651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 4280f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4290f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4306bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return nullptr; 4310f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 4320f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 433767b3d2000a00c56e1a3c19372810e2b7d66b76cBenjamin Kramerstatic int SrcCmp(const std::pair<const CFGBlock *, const Stmt *> *p1, 434767b3d2000a00c56e1a3c19372810e2b7d66b76cBenjamin Kramer const std::pair<const CFGBlock *, const Stmt *> *p2) { 4354124c7a37b8aa1afd8cd9b503f2aa7c4d6bed467Benjamin Kramer if (p1->second->getLocStart() < p2->second->getLocStart()) 4364124c7a37b8aa1afd8cd9b503f2aa7c4d6bed467Benjamin Kramer return -1; 4374124c7a37b8aa1afd8cd9b503f2aa7c4d6bed467Benjamin Kramer if (p2->second->getLocStart() < p1->second->getLocStart()) 4384124c7a37b8aa1afd8cd9b503f2aa7c4d6bed467Benjamin Kramer return 1; 4394124c7a37b8aa1afd8cd9b503f2aa7c4d6bed467Benjamin Kramer return 0; 4400f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 4410f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4420f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekunsigned DeadCodeScan::scanBackwards(const clang::CFGBlock *Start, 4430f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek clang::reachable_code::Callback &CB) { 44472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 4450f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek unsigned count = 0; 4460f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek enqueue(Start); 447651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 4480f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek while (!WorkList.empty()) { 4490f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek const CFGBlock *Block = WorkList.pop_back_val(); 4500f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4510f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // It is possible that this block has been marked reachable after 4520f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // it was enqueued. 4530f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (Reachable[Block->getBlockID()]) 4540f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 4550f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4560f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // Look for any dead code within the block. 4570f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek const Stmt *S = findDeadCode(Block); 458651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 4590f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (!S) { 4600f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // No dead code. Possibly an empty block. Look at dead predecessors. 4610f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (CFGBlock::const_pred_iterator I = Block->pred_begin(), 4620f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek E = Block->pred_end(); I != E; ++I) { 4630f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (const CFGBlock *predBlock = *I) 4640f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek enqueue(predBlock); 4650f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4660f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 4670f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 468651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 469e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek // Specially handle macro-expanded code. 470e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek if (S->getLocStart().isMacroID()) { 471651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines count += scanMaybeReachableFromBlock(Block, PP, Reachable); 472e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek continue; 473e7a2764b2c98859aa42a3fd36d55cd34c7fe883eTed Kremenek } 474eeef924c4fcb79a3bcc8782afce343e641bbcb83Chandler Carruth 4750f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (isDeadCodeRoot(Block)) { 476651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines reportDeadCode(Block, S, CB); 477651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines count += scanMaybeReachableFromBlock(Block, PP, Reachable); 4780f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4790f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek else { 4800f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // Record this statement as the possibly best location in a 4810f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // strongly-connected component of dead code for emitting a 4820f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // warning. 4830f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek DeferredLocs.push_back(std::make_pair(Block, S)); 4840f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4850f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4860f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 4870f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // If we didn't find a dead root, then report the dead code with the 4880f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // earliest location. 4890f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (!DeferredLocs.empty()) { 4900f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek llvm::array_pod_sort(DeferredLocs.begin(), DeferredLocs.end(), SrcCmp); 4910f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (DeferredLocsTy::iterator I = DeferredLocs.begin(), 492651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines E = DeferredLocs.end(); I != E; ++I) { 493651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const CFGBlock *Block = I->first; 494651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (Reachable[Block->getBlockID()]) 4950f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 496651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines reportDeadCode(Block, I->second, CB); 497651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines count += scanMaybeReachableFromBlock(Block, PP, Reachable); 4980f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 4990f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek } 500651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 5010f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return count; 5020f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek} 5030f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 5040f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekstatic SourceLocation GetUnreachableLoc(const Stmt *S, 5050f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek SourceRange &R1, 5060f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek SourceRange &R2) { 5070f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek R1 = R2 = SourceRange(); 50872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 509892697dd2287caf7c29aaaa82909b0e90b8b63feTed Kremenek if (const Expr *Ex = dyn_cast<Expr>(S)) 510892697dd2287caf7c29aaaa82909b0e90b8b63feTed Kremenek S = Ex->IgnoreParenImpCasts(); 511892697dd2287caf7c29aaaa82909b0e90b8b63feTed Kremenek 51272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek switch (S->getStmtClass()) { 51372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::BinaryOperatorClass: { 51472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const BinaryOperator *BO = cast<BinaryOperator>(S); 51572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return BO->getOperatorLoc(); 51672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 51772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::UnaryOperatorClass: { 51872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const UnaryOperator *UO = cast<UnaryOperator>(S); 51972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = UO->getSubExpr()->getSourceRange(); 52072919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return UO->getOperatorLoc(); 52172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 52272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::CompoundAssignOperatorClass: { 52372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(S); 52472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = CAO->getLHS()->getSourceRange(); 52572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R2 = CAO->getRHS()->getSourceRange(); 52672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return CAO->getOperatorLoc(); 52772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 52856ca35d396d8692c384c785f9aeebcf22563fe1eJohn McCall case Expr::BinaryConditionalOperatorClass: 52972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::ConditionalOperatorClass: { 53056ca35d396d8692c384c785f9aeebcf22563fe1eJohn McCall const AbstractConditionalOperator *CO = 531651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines cast<AbstractConditionalOperator>(S); 53272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return CO->getQuestionLoc(); 53372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 53472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::MemberExprClass: { 53572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const MemberExpr *ME = cast<MemberExpr>(S); 53672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = ME->getSourceRange(); 53772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return ME->getMemberLoc(); 53872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 53972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::ArraySubscriptExprClass: { 54072919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(S); 54172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = ASE->getLHS()->getSourceRange(); 54272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R2 = ASE->getRHS()->getSourceRange(); 54372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return ASE->getRBracketLoc(); 54472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 54572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::CStyleCastExprClass: { 54672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const CStyleCastExpr *CSC = cast<CStyleCastExpr>(S); 54772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = CSC->getSubExpr()->getSourceRange(); 54872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return CSC->getLParenLoc(); 54972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 55072919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Expr::CXXFunctionalCastExprClass: { 55172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek const CXXFunctionalCastExpr *CE = cast <CXXFunctionalCastExpr>(S); 55272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = CE->getSubExpr()->getSourceRange(); 553cdd4b78583120222b82148626119b3e80ae1d291Eli Friedman return CE->getLocStart(); 55472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 55572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek case Stmt::CXXTryStmtClass: { 55672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc(); 55772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 558f85e193739c953358c865005855253af4f68a497John McCall case Expr::ObjCBridgedCastExprClass: { 559f85e193739c953358c865005855253af4f68a497John McCall const ObjCBridgedCastExpr *CSC = cast<ObjCBridgedCastExpr>(S); 560f85e193739c953358c865005855253af4f68a497John McCall R1 = CSC->getSubExpr()->getSourceRange(); 561f85e193739c953358c865005855253af4f68a497John McCall return CSC->getLParenLoc(); 562f85e193739c953358c865005855253af4f68a497John McCall } 56372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek default: ; 56472919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 56572919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek R1 = S->getSourceRange(); 56672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return S->getLocStart(); 56772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek} 56872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 569651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesvoid DeadCodeScan::reportDeadCode(const CFGBlock *B, 570651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *S, 5710f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek clang::reachable_code::Callback &CB) { 572651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Classify the unreachable code found, or suppress it in some cases. 573651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines reachable_code::UnreachableKind UK = reachable_code::UK_Other; 574651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 575651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (isa<BreakStmt>(S)) { 576651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines UK = reachable_code::UK_Break; 577651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 578651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines else if (isTrivialDoWhile(B, S)) { 579651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return; 580651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 581651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines else if (isDeadReturn(B, S)) { 582651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines UK = reachable_code::UK_Return; 583651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 584651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 585651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceRange SilenceableCondVal; 586651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 587651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (UK == reachable_code::UK_Other) { 588651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Check if the dead code is part of the "loop target" of 589651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // a for/for-range loop. This is the block that contains 590651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // the increment code. 591651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const Stmt *LoopTarget = B->getLoopTarget()) { 592651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceLocation Loc = LoopTarget->getLocStart(); 593651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines SourceRange R1(Loc, Loc), R2; 594651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 595651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const ForStmt *FS = dyn_cast<ForStmt>(LoopTarget)) { 596651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Expr *Inc = FS->getInc(); 597651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Loc = Inc->getLocStart(); 598651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines R2 = Inc->getSourceRange(); 599651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 600651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 601651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines CB.HandleUnreachable(reachable_code::UK_Loop_Increment, 602651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Loc, SourceRange(), SourceRange(Loc, Loc), R2); 603651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines return; 604651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 605651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 606651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Check if the dead block has a predecessor whose branch has 607651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // a configuration value that *could* be modified to 608651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // silence the warning. 609651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines CFGBlock::const_pred_iterator PI = B->pred_begin(); 610651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (PI != B->pred_end()) { 611651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines if (const CFGBlock *PredBlock = PI->getPossiblyUnreachableBlock()) { 612651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines const Stmt *TermCond = 613651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines PredBlock->getTerminatorCondition(/* strip parens */ false); 614651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines isConfigurationValue(TermCond, PP, &SilenceableCondVal); 615651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 616651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 617651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines } 618651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 61972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek SourceRange R1, R2; 6200f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek SourceLocation Loc = GetUnreachableLoc(S, R1, R2); 621651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines CB.HandleUnreachable(UK, Loc, SilenceableCondVal, R1, R2); 62272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek} 62372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 624651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 625651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines// Reachability APIs. 626651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines//===----------------------------------------------------------------------===// 627651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 62872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremeneknamespace clang { namespace reachable_code { 62999ba9e3bd70671f3441fb974895f226a83ce0e66David Blaikie 630651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesvoid Callback::anchor() { } 63199ba9e3bd70671f3441fb974895f226a83ce0e66David Blaikie 6320f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenekunsigned ScanReachableFromBlock(const CFGBlock *Start, 63372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek llvm::BitVector &Reachable) { 6346bcf27bb9a4b5c3f79cb44c0e4654a6d7619ad89Stephen Hines return scanFromBlock(Start, Reachable, /* SourceManager* */ nullptr, false); 6353d2eed823d534ee370cfd7742c1e96ab3ee9a80bTed Kremenek} 636651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 637651f13cea278ec967336033dd032faef0e9fc2ecStephen Hinesvoid FindUnreachableCode(AnalysisDeclContext &AC, Preprocessor &PP, 638651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines Callback &CB) { 639651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines 64072919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek CFG *cfg = AC.getCFG(); 64172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek if (!cfg) 64272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return; 64372919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 644651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines // Scan for reachable blocks from the entrance of the CFG. 6450f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // If there are no unreachable blocks, we're done. 64672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek llvm::BitVector reachable(cfg->getNumBlockIDs()); 647651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines unsigned numReachable = 648651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines scanMaybeReachableFromBlock(&cfg->getEntry(), PP, reachable); 64972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek if (numReachable == cfg->getNumBlockIDs()) 65072919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek return; 6510f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 6520f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // If there aren't explicit EH edges, we should include the 'try' dispatch 6530f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // blocks as roots. 6540f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (!AC.getCFGBuildOptions().AddEHEdges) { 6550f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (CFG::try_block_iterator I = cfg->try_blocks_begin(), 6560f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek E = cfg->try_blocks_end() ; I != E; ++I) { 657651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines numReachable += scanMaybeReachableFromBlock(*I, PP, reachable); 65872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 6590f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (numReachable == cfg->getNumBlockIDs()) 6600f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return; 66172919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 66272919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 6630f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // There are some unreachable blocks. We need to find the root blocks that 6640f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // contain code that should be considered unreachable. 6650f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) { 6660f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek const CFGBlock *block = *I; 6670f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek // A block may have been marked reachable during this loop. 6680f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (reachable[block->getBlockID()]) 6690f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek continue; 6700f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 671651f13cea278ec967336033dd032faef0e9fc2ecStephen Hines DeadCodeScan DS(reachable, PP); 6720f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek numReachable += DS.scanBackwards(block, CB); 6730f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek 6740f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek if (numReachable == cfg->getNumBlockIDs()) 6750f3b4ca1764cd6d457f511d340fba504f41763c3Ted Kremenek return; 67672919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek } 67772919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek} 67872919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek 67972919a334752bc87001a7e3a0b6e5892768fac20Ted Kremenek}} // end namespace clang::reachable_code 680