1 //===- ControlFlowContext.cpp ---------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines a ControlFlowContext class that is used by dataflow 10 // analyses that run over Control-Flow Graphs (CFGs). 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/Analysis/FlowSensitive/ControlFlowContext.h" 15 #include "clang/AST/ASTContext.h" 16 #include "clang/AST/Decl.h" 17 #include "clang/AST/Stmt.h" 18 #include "clang/Analysis/CFG.h" 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/Support/Error.h" 21 #include <utility> 22 23 namespace clang { 24 namespace dataflow { 25 26 /// Returns a map from statements to basic blocks that contain them. 27 static llvm::DenseMap<const Stmt *, const CFGBlock *> 28 buildStmtToBasicBlockMap(const CFG &Cfg) { 29 llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock; 30 for (const CFGBlock *Block : Cfg) { 31 if (Block == nullptr) 32 continue; 33 34 for (const CFGElement &Element : *Block) { 35 auto Stmt = Element.getAs<CFGStmt>(); 36 if (!Stmt) 37 continue; 38 39 StmtToBlock[Stmt.value().getStmt()] = Block; 40 } 41 if (const Stmt *TerminatorStmt = Block->getTerminatorStmt()) 42 StmtToBlock[TerminatorStmt] = Block; 43 } 44 return StmtToBlock; 45 } 46 47 llvm::Expected<ControlFlowContext> 48 ControlFlowContext::build(const Decl *D, Stmt *S, ASTContext *C) { 49 CFG::BuildOptions Options; 50 Options.PruneTriviallyFalseEdges = false; 51 Options.AddImplicitDtors = true; 52 Options.AddTemporaryDtors = true; 53 Options.AddInitializers = true; 54 Options.AddCXXDefaultInitExprInCtors = true; 55 56 // Ensure that all sub-expressions in basic blocks are evaluated. 57 Options.setAllAlwaysAdd(); 58 59 auto Cfg = CFG::buildCFG(D, S, C, Options); 60 if (Cfg == nullptr) 61 return llvm::createStringError( 62 std::make_error_code(std::errc::invalid_argument), 63 "CFG::buildCFG failed"); 64 65 llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock = 66 buildStmtToBasicBlockMap(*Cfg); 67 return ControlFlowContext(std::move(Cfg), std::move(StmtToBlock)); 68 } 69 70 } // namespace dataflow 71 } // namespace clang 72