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New implementation of data structure analysis. Only local analysis has been
implemented so far. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2871 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
283
lib/Analysis/DataStructure/Local.cpp
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283
lib/Analysis/DataStructure/Local.cpp
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//===- ComputeLocal.cpp - Compute a local data structure graph for a fn ---===//
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//
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// Compute the local version of the data structure graph for a function. The
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// external interface to this file is the DSGraph constructor.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/DataStructure.h"
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#include "llvm/Function.h"
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#include "llvm/iMemory.h"
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#include "llvm/iTerminators.h"
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#include "llvm/iPHINode.h"
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#include "llvm/iOther.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Support/InstVisitor.h"
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using std::map;
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using std::vector;
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//===----------------------------------------------------------------------===//
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// GraphBuilder Class
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//===----------------------------------------------------------------------===//
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//
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// This class is the builder class that constructs the local data structure
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// graph by performing a single pass over the function in question.
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//
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namespace {
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class GraphBuilder : InstVisitor<GraphBuilder> {
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DSGraph &G;
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vector<DSNode*> &Nodes;
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DSNodeHandle &RetNode; // Node that gets returned...
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map<Value*, DSNodeHandle> &ValueMap;
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vector<vector<DSNodeHandle> > &FunctionCalls;
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public:
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GraphBuilder(DSGraph &g, vector<DSNode*> &nodes, DSNodeHandle &retNode,
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map<Value*, DSNodeHandle> &vm,
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vector<vector<DSNodeHandle> > &fc)
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: G(g), Nodes(nodes), RetNode(retNode), ValueMap(vm), FunctionCalls(fc) {
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visit(G.getFunction()); // Single pass over the function
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removeDeadNodes();
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}
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private:
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// Visitor functions, used to handle each instruction type we encounter...
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friend class InstVisitor<GraphBuilder>;
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void visitMallocInst(MallocInst &MI) { handleAlloc(MI, DSNode::NewNode); }
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void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, DSNode::AllocaNode);}
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void handleAlloc(AllocationInst &AI, DSNode::NodeTy NT);
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void visitPHINode(PHINode &PN);
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void visitGetElementPtrInst(GetElementPtrInst &GEP);
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void visitReturnInst(ReturnInst &RI);
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void visitLoadInst(LoadInst &LI);
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void visitStoreInst(StoreInst &SI);
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void visitCallInst(CallInst &CI);
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void visitSetCondInst(SetCondInst &SCI) {} // SetEQ & friends are ignored
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void visitFreeInst(FreeInst &FI) {} // Ignore free instructions
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void visitInstruction(Instruction &I) {
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#ifndef NDEBUG
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bool bad = isa<PointerType>(I.getType());
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for (Instruction::op_iterator i = I.op_begin(), E = I.op_end(); i!=E; ++i)
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bad |= isa<PointerType>(i->get()->getType());
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if (bad) {
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std::cerr << "\n\n\nUNKNOWN PTR INSTRUCTION type: " << I << "\n\n\n";
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assert(0 && "Cannot proceed");
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}
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#endif
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}
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private:
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// Helper functions used to implement the visitation functions...
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// createNode - Create a new DSNode, ensuring that it is properly added to
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// the graph.
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//
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DSNode *createNode(DSNode::NodeTy NodeType, const Type *Ty);
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// getValueNode - Return a DSNode that corresponds the the specified LLVM
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// value. This either returns the already existing node, or creates a new
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// one and adds it to the graph, if none exists.
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//
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DSNode *getValueNode(Value &V);
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// getLink - This method is used to either return the specified link in the
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// specified node if one exists. If a link does not already exist (it's
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// null), then we create a new node, link it, then return it.
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//
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DSNode *getLink(DSNode *Node, unsigned Link);
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// getSubscriptedNode - Perform the basic getelementptr functionality that
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// must be factored out of gep, load and store while they are all MAI's.
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//
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DSNode *getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr);
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// removeDeadNodes - After the graph has been constructed, this method
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// removes all unreachable nodes that are created because they got merged
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// with other nodes in the graph.
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//
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void removeDeadNodes();
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};
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}
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//===----------------------------------------------------------------------===//
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// DSGraph constructor - Simply use the GraphBuilder to construct the local
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// graph.
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DSGraph::DSGraph(Function &F) : Func(F), RetNode(0) {
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// Use the graph builder to construct the local version of the graph
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GraphBuilder B(*this, Nodes, RetNode, ValueMap, FunctionCalls);
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}
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//===----------------------------------------------------------------------===//
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// Helper method implementations...
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//
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// createNode - Create a new DSNode, ensuring that it is properly added to the
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// graph.
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//
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DSNode *GraphBuilder::createNode(DSNode::NodeTy NodeType, const Type *Ty) {
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DSNode *N = new DSNode(NodeType, Ty);
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Nodes.push_back(N);
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return N;
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}
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// getValueNode - Return a DSNode that corresponds the the specified LLVM value.
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// This either returns the already existing node, or creates a new one and adds
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// it to the graph, if none exists.
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//
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DSNode *GraphBuilder::getValueNode(Value &V) {
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assert(isa<PointerType>(V.getType()) && "Should only use pointer scalars!");
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DSNodeHandle &N = ValueMap[&V];
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if (N) return N; // Already have a node? Just return it...
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// Otherwise we need to create a new scalar node...
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N = createNode(DSNode::ScalarNode, V.getType());
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if (isa<GlobalValue>(V)) {
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// Traverse the global graph, adding nodes for them all, and marking them
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// all globals. Be careful to mark functions global as well as the
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// potential graph of global variables.
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//
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DSNode *G = getLink(N, 0);
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G->NodeType |= DSNode::GlobalNode;
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}
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return N;
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}
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// getLink - This method is used to either return the specified link in the
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// specified node if one exists. If a link does not already exist (it's
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// null), then we create a new node, link it, then return it.
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//
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DSNode *GraphBuilder::getLink(DSNode *Node, unsigned Link) {
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assert(Link < Node->getNumLinks() && "Link accessed out of range!");
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if (Node->getLink(Link) == 0) {
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DSNode::NodeTy NT;
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const Type *Ty;
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switch (Node->getType()->getPrimitiveID()) {
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case Type::PointerTyID:
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Ty = cast<PointerType>(Node->getType())->getElementType();
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NT = DSNode::ShadowNode;
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break;
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case Type::ArrayTyID:
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Ty = cast<ArrayType>(Node->getType())->getElementType();
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NT = DSNode::SubElement;
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break;
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case Type::StructTyID:
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Ty = cast<StructType>(Node->getType())->getContainedType(Link);
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NT = DSNode::SubElement;
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break;
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default:
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assert(0 && "Unexpected type to dereference!");
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abort();
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}
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DSNode *New = createNode(NT, Ty);
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Node->addEdgeTo(Link, New);
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}
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return Node->getLink(Link);
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}
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// getSubscriptedNode - Perform the basic getelementptr functionality that must
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// be factored out of gep, load and store while they are all MAI's.
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//
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DSNode *GraphBuilder::getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr) {
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for (unsigned i = MAI.getFirstIndexOperandNumber(), e = MAI.getNumOperands();
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i != e; ++i)
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if (MAI.getOperand(i)->getType() == Type::UIntTy)
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Ptr = getLink(Ptr, 0);
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else if (MAI.getOperand(i)->getType() == Type::UByteTy)
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Ptr = getLink(Ptr, cast<ConstantUInt>(MAI.getOperand(i))->getValue());
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if (MAI.getFirstIndexOperandNumber() == MAI.getNumOperands())
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Ptr = getLink(Ptr, 0); // All MAI's have an implicit 0 if nothing else.
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return Ptr;
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}
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// removeDeadNodes - After the graph has been constructed, this method removes
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// all unreachable nodes that are created because they got merged with other
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// nodes in the graph. These nodes will all be trivially unreachable, so we
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// don't have to perform any non-trivial analysis here.
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//
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void GraphBuilder::removeDeadNodes() {
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for (unsigned i = 0; i != Nodes.size(); )
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if (!Nodes[i]->getReferrers().empty())
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++i; // This node is alive!
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else { // This node is dead!
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delete Nodes[i]; // Free memory...
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Nodes.erase(Nodes.begin()+i); // Remove from node list...
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}
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}
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//===----------------------------------------------------------------------===//
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// Specific instruction type handler implementations...
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//
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// Alloca & Malloc instruction implementation - Simply create a new memory
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// object, pointing the scalar to it.
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//
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void GraphBuilder::handleAlloc(AllocationInst &AI, DSNode::NodeTy NodeType) {
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DSNode *Scalar = getValueNode(AI);
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DSNode *New = createNode(NodeType, AI.getAllocatedType());
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Scalar->addEdgeTo(New); // Make the scalar point to the new node...
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}
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// PHINode - Make the scalar for the PHI node point to all of the things the
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// incoming values point to... which effectively causes them to be merged.
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//
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void GraphBuilder::visitPHINode(PHINode &PN) {
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if (!isa<PointerType>(PN.getType())) return; // Only pointer PHIs
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DSNode *Scalar = getValueNode(PN);
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for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
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Scalar->mergeWith(getValueNode(*PN.getIncomingValue(i)));
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}
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void GraphBuilder::visitGetElementPtrInst(GetElementPtrInst &GEP) {
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DSNode *Scalar = getValueNode(GEP);
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DSNode *Ptr = getSubscriptedNode(GEP, getValueNode(*GEP.getOperand(0)));
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Scalar->addEdgeTo(Ptr);
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}
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void GraphBuilder::visitLoadInst(LoadInst &LI) {
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if (!isa<PointerType>(LI.getType())) return; // Only pointer PHIs
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DSNode *Ptr = getSubscriptedNode(LI, getValueNode(*LI.getOperand(0)));
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getValueNode(LI)->mergeWith(Ptr);
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}
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void GraphBuilder::visitStoreInst(StoreInst &SI) {
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if (!isa<PointerType>(SI.getOperand(0)->getType())) return;
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DSNode *Value = getValueNode(*SI.getOperand(0));
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DSNode *DestPtr = getValueNode(*SI.getOperand(1));
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Value->mergeWith(getSubscriptedNode(SI, DestPtr));
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}
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void GraphBuilder::visitReturnInst(ReturnInst &RI) {
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if (RI.getNumOperands() && isa<PointerType>(RI.getOperand(0)->getType())) {
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DSNode *Value = getValueNode(*RI.getOperand(0));
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Value->mergeWith(RetNode);
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RetNode = Value;
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}
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}
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void GraphBuilder::visitCallInst(CallInst &CI) {
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FunctionCalls.push_back(vector<DSNodeHandle>());
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vector<DSNodeHandle> &Args = FunctionCalls.back();
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for (unsigned i = 0, e = CI.getNumOperands(); i != e; ++i)
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if (isa<PointerType>(CI.getOperand(i)->getType()))
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Args.push_back(getValueNode(*CI.getOperand(i)));
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}
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