136 lines · cpp
1//===-- HelperDeclRefGraph.cpp - AST-based call graph for helper decls ----===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "HelperDeclRefGraph.h"10#include "Move.h"11#include "clang/AST/Decl.h"12#include "llvm/Support/Debug.h"13#include <vector>14 15#define DEBUG_TYPE "clang-move"16 17namespace clang {18namespace move {19 20void HelperDeclRefGraph::print(raw_ostream &OS) const {21 OS << " --- Call graph Dump --- \n";22 for (auto I = DeclMap.begin(); I != DeclMap.end(); ++I) {23 const CallGraphNode *N = (I->second).get();24 25 OS << " Declarations: ";26 N->print(OS);27 OS << " (" << N << ") ";28 OS << " calls: ";29 for (auto CI = N->begin(), CE = N->end(); CI != CE; ++CI) {30 CI->Callee->print(OS);31 OS << " (" << CI << ") ";32 }33 OS << '\n';34 }35 OS.flush();36}37 38void HelperDeclRefGraph::addEdge(const Decl *Caller, const Decl *Callee) {39 assert(Caller);40 assert(Callee);41 42 // Ignore the case where Caller equals Callee. This happens in the static43 // class member definitions in global namespace like "int CLASS::static_var =44 // 1;", its DC is a VarDel whose outmost enclosing declaration is the "CLASS"45 // CXXRecordDecl.46 if (Caller == Callee) return;47 48 // Allocate a new node, mark it as root, and process it's calls.49 CallGraphNode *CallerNode = getOrInsertNode(const_cast<Decl *>(Caller));50 CallGraphNode *CalleeNode = getOrInsertNode(const_cast<Decl *>(Callee));51 CallerNode->addCallee({CalleeNode, /*CallExpr=*/nullptr});52}53 54void HelperDeclRefGraph::dump() const { print(llvm::errs()); }55 56CallGraphNode *HelperDeclRefGraph::getOrInsertNode(Decl *F) {57 F = F->getCanonicalDecl();58 std::unique_ptr<CallGraphNode> &Node = DeclMap[F];59 if (Node)60 return Node.get();61 62 Node = std::make_unique<CallGraphNode>(F);63 return Node.get();64}65 66CallGraphNode *HelperDeclRefGraph::getNode(const Decl *D) const {67 auto I = DeclMap.find(D->getCanonicalDecl());68 return I == DeclMap.end() ? nullptr : I->second.get();69}70 71llvm::DenseSet<const CallGraphNode *>72HelperDeclRefGraph::getReachableNodes(const Decl *Root) const {73 const auto *RootNode = getNode(Root);74 if (!RootNode)75 return {};76 llvm::DenseSet<const CallGraphNode *> ConnectedNodes;77 std::function<void(const CallGraphNode *)> VisitNode =78 [&](const CallGraphNode *Node) {79 if (!ConnectedNodes.insert(Node).second)80 return;81 for (const CallGraphNode::CallRecord &Callee : *Node)82 VisitNode(Callee);83 };84 85 VisitNode(RootNode);86 return ConnectedNodes;87}88 89const Decl *HelperDeclRGBuilder::getOutmostClassOrFunDecl(const Decl *D) {90 const auto *DC = D->getDeclContext();91 const auto *Result = D;92 while (DC) {93 if (const auto *RD = dyn_cast<CXXRecordDecl>(DC))94 Result = RD;95 else if (const auto *FD = dyn_cast<FunctionDecl>(DC))96 Result = FD;97 DC = DC->getParent();98 }99 return Result;100}101 102void HelperDeclRGBuilder::run(103 const ast_matchers::MatchFinder::MatchResult &Result) {104 // Construct the graph by adding a directed edge from caller to callee.105 //106 // "dc" is the closest ancestor declaration of "func_ref" or "used_class", it107 // might be not the targetted Caller Decl, we always use the outmost enclosing108 // FunctionDecl/CXXRecordDecl of "dc". For example,109 //110 // int MoveClass::F() { int a = helper(); return a; }111 //112 // The matched "dc" of "helper" DeclRefExpr is a VarDecl, we traverse up AST113 // to find the outmost "MoveClass" CXXRecordDecl and use it as Caller.114 if (const auto *FuncRef = Result.Nodes.getNodeAs<DeclRefExpr>("func_ref")) {115 const auto *DC = Result.Nodes.getNodeAs<Decl>("dc");116 assert(DC);117 LLVM_DEBUG(llvm::dbgs() << "Find helper function usage: "118 << FuncRef->getDecl()->getDeclName() << " ("119 << FuncRef->getDecl() << ")\n");120 RG->addEdge(121 getOutmostClassOrFunDecl(DC->getCanonicalDecl()),122 getOutmostClassOrFunDecl(FuncRef->getDecl()->getCanonicalDecl()));123 } else if (const auto *UsedClass =124 Result.Nodes.getNodeAs<CXXRecordDecl>("used_class")) {125 const auto *DC = Result.Nodes.getNodeAs<Decl>("dc");126 assert(DC);127 LLVM_DEBUG(llvm::dbgs()128 << "Find helper class usage: " << UsedClass->getDeclName()129 << " (" << UsedClass << ")\n");130 RG->addEdge(getOutmostClassOrFunDecl(DC->getCanonicalDecl()), UsedClass);131 }132}133 134} // namespace move135} // namespace clang136