244 lines
7.3 KiB
C++
244 lines
7.3 KiB
C++
//=-- ExplodedGraph.cpp - Local, Path-Sens. "Exploded Graph" -*- C++ -*------=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the template classes ExplodedNode and ExplodedGraph,
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// which represent a path-sensitive, intra-procedural "exploded graph."
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/PathSensitive/ExplodedGraph.h"
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#include "clang/AST/Stmt.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include <vector>
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#include <list>
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using namespace clang;
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//===----------------------------------------------------------------------===//
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// Node auditing.
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//===----------------------------------------------------------------------===//
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// An out of line virtual method to provide a home for the class vtable.
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ExplodedNodeImpl::Auditor::~Auditor() {}
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#ifndef NDEBUG
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static ExplodedNodeImpl::Auditor* NodeAuditor = 0;
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#endif
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void ExplodedNodeImpl::SetAuditor(ExplodedNodeImpl::Auditor* A) {
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#ifndef NDEBUG
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NodeAuditor = A;
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#endif
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}
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//===----------------------------------------------------------------------===//
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// ExplodedNodeImpl.
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//===----------------------------------------------------------------------===//
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static inline std::vector<ExplodedNodeImpl*>& getVector(void* P) {
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return *reinterpret_cast<std::vector<ExplodedNodeImpl*>*>(P);
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}
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void ExplodedNodeImpl::addPredecessor(ExplodedNodeImpl* V) {
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assert (!V->isSink());
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Preds.addNode(V);
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V->Succs.addNode(this);
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#ifndef NDEBUG
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if (NodeAuditor) NodeAuditor->AddEdge(V, this);
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#endif
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}
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void ExplodedNodeImpl::NodeGroup::addNode(ExplodedNodeImpl* N) {
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assert ((reinterpret_cast<uintptr_t>(N) & Mask) == 0x0);
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assert (!getFlag());
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if (getKind() == Size1) {
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if (ExplodedNodeImpl* NOld = getNode()) {
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std::vector<ExplodedNodeImpl*>* V = new std::vector<ExplodedNodeImpl*>();
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assert ((reinterpret_cast<uintptr_t>(V) & Mask) == 0x0);
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V->push_back(NOld);
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V->push_back(N);
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P = reinterpret_cast<uintptr_t>(V) | SizeOther;
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assert (getPtr() == (void*) V);
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assert (getKind() == SizeOther);
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}
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else {
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P = reinterpret_cast<uintptr_t>(N);
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assert (getKind() == Size1);
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}
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}
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else {
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assert (getKind() == SizeOther);
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getVector(getPtr()).push_back(N);
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}
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}
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unsigned ExplodedNodeImpl::NodeGroup::size() const {
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if (getFlag())
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return 0;
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if (getKind() == Size1)
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return getNode() ? 1 : 0;
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else
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return getVector(getPtr()).size();
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}
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ExplodedNodeImpl** ExplodedNodeImpl::NodeGroup::begin() const {
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if (getFlag())
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return NULL;
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if (getKind() == Size1)
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return (ExplodedNodeImpl**) (getPtr() ? &P : NULL);
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else
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return const_cast<ExplodedNodeImpl**>(&*(getVector(getPtr()).begin()));
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}
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ExplodedNodeImpl** ExplodedNodeImpl::NodeGroup::end() const {
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if (getFlag())
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return NULL;
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if (getKind() == Size1)
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return (ExplodedNodeImpl**) (getPtr() ? &P+1 : NULL);
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else {
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// Dereferencing end() is undefined behaviour. The vector is not empty, so
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// we can dereference the last elem and then add 1 to the result.
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return const_cast<ExplodedNodeImpl**>(&getVector(getPtr()).back()) + 1;
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}
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}
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ExplodedNodeImpl::NodeGroup::~NodeGroup() {
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if (getKind() == SizeOther) delete &getVector(getPtr());
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}
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ExplodedGraphImpl*
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ExplodedGraphImpl::Trim(const ExplodedNodeImpl* const* BeginSources,
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const ExplodedNodeImpl* const* EndSources,
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InterExplodedGraphMapImpl* M,
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llvm::DenseMap<const void*, const void*> *InverseMap)
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const {
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typedef llvm::DenseSet<const ExplodedNodeImpl*> Pass1Ty;
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Pass1Ty Pass1;
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typedef llvm::DenseMap<const ExplodedNodeImpl*, ExplodedNodeImpl*> Pass2Ty;
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Pass2Ty& Pass2 = M->M;
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std::list<const ExplodedNodeImpl*> WL1;
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llvm::SmallVector<const ExplodedNodeImpl*, 10> WL2;
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// ===- Pass 1 (reverse BFS) -===
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for (const ExplodedNodeImpl* const* I = BeginSources; I != EndSources; ++I) {
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assert(*I);
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WL1.push_back(*I);
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}
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// Process the first worklist until it is empty. Because it is a std::list
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// it acts like a FIFO queue.
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while (!WL1.empty()) {
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const ExplodedNodeImpl *N = WL1.back();
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WL1.pop_back();
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// Have we already visited this node? If so, continue to the next one.
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if (Pass1.count(N))
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continue;
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// Otherwise, mark this node as visited.
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Pass1.insert(N);
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// If this is a root enqueue it to the second worklist.
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if (N->Preds.empty()) {
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WL2.push_back(N);
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continue;
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}
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// Visit our predecessors and enqueue them.
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for (ExplodedNodeImpl** I=N->Preds.begin(), **E=N->Preds.end(); I!=E; ++I)
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WL1.push_front(*I);
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}
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// We didn't hit a root? Return with a null pointer for the new graph.
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if (WL2.empty())
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return 0;
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// Create an empty graph.
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ExplodedGraphImpl* G = MakeEmptyGraph();
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// ===- Pass 2 (forward DFS to construct the new graph) -===
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while (!WL2.empty()) {
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const ExplodedNodeImpl* N = WL2.back();
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WL2.pop_back();
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// Skip this node if we have already processed it.
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if (Pass2.find(N) != Pass2.end())
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continue;
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// Create the corresponding node in the new graph and record the mapping
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// from the old node to the new node.
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ExplodedNodeImpl* NewN = G->getNodeImpl(N->getLocation(), N->State, NULL);
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Pass2[N] = NewN;
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// Also record the reverse mapping from the new node to the old node.
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if (InverseMap) (*InverseMap)[NewN] = N;
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// If this node is a root, designate it as such in the graph.
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if (N->Preds.empty())
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G->addRoot(NewN);
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// In the case that some of the intended predecessors of NewN have already
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// been created, we should hook them up as predecessors.
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// Walk through the predecessors of 'N' and hook up their corresponding
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// nodes in the new graph (if any) to the freshly created node.
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for (ExplodedNodeImpl **I=N->Preds.begin(), **E=N->Preds.end(); I!=E; ++I) {
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Pass2Ty::iterator PI = Pass2.find(*I);
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if (PI == Pass2.end())
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continue;
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NewN->addPredecessor(PI->second);
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}
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// In the case that some of the intended successors of NewN have already
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// been created, we should hook them up as successors. Otherwise, enqueue
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// the new nodes from the original graph that should have nodes created
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// in the new graph.
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for (ExplodedNodeImpl **I=N->Succs.begin(), **E=N->Succs.end(); I!=E; ++I) {
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Pass2Ty::iterator PI = Pass2.find(*I);
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if (PI != Pass2.end()) {
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PI->second->addPredecessor(NewN);
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continue;
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}
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// Enqueue nodes to the worklist that were marked during pass 1.
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if (Pass1.count(*I))
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WL2.push_back(*I);
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}
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// Finally, explictly mark all nodes without any successors as sinks.
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if (N->isSink())
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NewN->markAsSink();
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}
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return G;
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}
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ExplodedNodeImpl*
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InterExplodedGraphMapImpl::getMappedImplNode(const ExplodedNodeImpl* N) const {
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llvm::DenseMap<const ExplodedNodeImpl*, ExplodedNodeImpl*>::iterator I =
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M.find(N);
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return I == M.end() ? 0 : I->second;
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}
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InterExplodedGraphMapImpl::InterExplodedGraphMapImpl() {}
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