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
diff --git a/lib/Analysis/DataStructure/Local.cpp b/lib/Analysis/DataStructure/Local.cpp
new file mode 100644
index 0000000..87767ce
--- /dev/null
+++ b/lib/Analysis/DataStructure/Local.cpp
@@ -0,0 +1,283 @@
+//===- ComputeLocal.cpp - Compute a local data structure graph for a fn ---===//
+//
+// Compute the local version of the data structure graph for a function. The
+// external interface to this file is the DSGraph constructor.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/DataStructure.h"
+#include "llvm/Function.h"
+#include "llvm/iMemory.h"
+#include "llvm/iTerminators.h"
+#include "llvm/iPHINode.h"
+#include "llvm/iOther.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Support/InstVisitor.h"
+using std::map;
+using std::vector;
+
+//===----------------------------------------------------------------------===//
+// GraphBuilder Class
+//===----------------------------------------------------------------------===//
+//
+// This class is the builder class that constructs the local data structure
+// graph by performing a single pass over the function in question.
+//
+
+namespace {
+ class GraphBuilder : InstVisitor<GraphBuilder> {
+ DSGraph &G;
+ vector<DSNode*> &Nodes;
+ DSNodeHandle &RetNode; // Node that gets returned...
+ map<Value*, DSNodeHandle> &ValueMap;
+ vector<vector<DSNodeHandle> > &FunctionCalls;
+
+ public:
+ GraphBuilder(DSGraph &g, vector<DSNode*> &nodes, DSNodeHandle &retNode,
+ map<Value*, DSNodeHandle> &vm,
+ vector<vector<DSNodeHandle> > &fc)
+ : G(g), Nodes(nodes), RetNode(retNode), ValueMap(vm), FunctionCalls(fc) {
+ visit(G.getFunction()); // Single pass over the function
+ removeDeadNodes();
+ }
+
+ private:
+ // Visitor functions, used to handle each instruction type we encounter...
+ friend class InstVisitor<GraphBuilder>;
+ void visitMallocInst(MallocInst &MI) { handleAlloc(MI, DSNode::NewNode); }
+ void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, DSNode::AllocaNode);}
+ void handleAlloc(AllocationInst &AI, DSNode::NodeTy NT);
+
+ void visitPHINode(PHINode &PN);
+
+ void visitGetElementPtrInst(GetElementPtrInst &GEP);
+ void visitReturnInst(ReturnInst &RI);
+ void visitLoadInst(LoadInst &LI);
+ void visitStoreInst(StoreInst &SI);
+ void visitCallInst(CallInst &CI);
+ void visitSetCondInst(SetCondInst &SCI) {} // SetEQ & friends are ignored
+ void visitFreeInst(FreeInst &FI) {} // Ignore free instructions
+ void visitInstruction(Instruction &I) {
+#ifndef NDEBUG
+ bool bad = isa<PointerType>(I.getType());
+ for (Instruction::op_iterator i = I.op_begin(), E = I.op_end(); i!=E; ++i)
+ bad |= isa<PointerType>(i->get()->getType());
+ if (bad) {
+ std::cerr << "\n\n\nUNKNOWN PTR INSTRUCTION type: " << I << "\n\n\n";
+ assert(0 && "Cannot proceed");
+ }
+#endif
+ }
+
+ private:
+ // Helper functions used to implement the visitation functions...
+
+ // createNode - Create a new DSNode, ensuring that it is properly added to
+ // the graph.
+ //
+ DSNode *createNode(DSNode::NodeTy NodeType, const Type *Ty);
+
+ // getValueNode - Return a DSNode that corresponds the the specified LLVM
+ // value. This either returns the already existing node, or creates a new
+ // one and adds it to the graph, if none exists.
+ //
+ DSNode *getValueNode(Value &V);
+
+ // getLink - This method is used to either return the specified link in the
+ // specified node if one exists. If a link does not already exist (it's
+ // null), then we create a new node, link it, then return it.
+ //
+ DSNode *getLink(DSNode *Node, unsigned Link);
+
+ // getSubscriptedNode - Perform the basic getelementptr functionality that
+ // must be factored out of gep, load and store while they are all MAI's.
+ //
+ DSNode *getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr);
+
+ // removeDeadNodes - After the graph has been constructed, this method
+ // removes all unreachable nodes that are created because they got merged
+ // with other nodes in the graph.
+ //
+ void removeDeadNodes();
+ };
+}
+
+//===----------------------------------------------------------------------===//
+// DSGraph constructor - Simply use the GraphBuilder to construct the local
+// graph.
+DSGraph::DSGraph(Function &F) : Func(F), RetNode(0) {
+ // Use the graph builder to construct the local version of the graph
+ GraphBuilder B(*this, Nodes, RetNode, ValueMap, FunctionCalls);
+}
+
+
+//===----------------------------------------------------------------------===//
+// Helper method implementations...
+//
+
+
+// createNode - Create a new DSNode, ensuring that it is properly added to the
+// graph.
+//
+DSNode *GraphBuilder::createNode(DSNode::NodeTy NodeType, const Type *Ty) {
+ DSNode *N = new DSNode(NodeType, Ty);
+ Nodes.push_back(N);
+ return N;
+}
+
+
+// getValueNode - Return a DSNode that corresponds the the specified LLVM value.
+// This either returns the already existing node, or creates a new one and adds
+// it to the graph, if none exists.
+//
+DSNode *GraphBuilder::getValueNode(Value &V) {
+ assert(isa<PointerType>(V.getType()) && "Should only use pointer scalars!");
+ DSNodeHandle &N = ValueMap[&V];
+ if (N) return N; // Already have a node? Just return it...
+
+ // Otherwise we need to create a new scalar node...
+ N = createNode(DSNode::ScalarNode, V.getType());
+
+ if (isa<GlobalValue>(V)) {
+ // Traverse the global graph, adding nodes for them all, and marking them
+ // all globals. Be careful to mark functions global as well as the
+ // potential graph of global variables.
+ //
+ DSNode *G = getLink(N, 0);
+ G->NodeType |= DSNode::GlobalNode;
+ }
+
+ return N;
+}
+
+// getLink - This method is used to either return the specified link in the
+// specified node if one exists. If a link does not already exist (it's
+// null), then we create a new node, link it, then return it.
+//
+DSNode *GraphBuilder::getLink(DSNode *Node, unsigned Link) {
+ assert(Link < Node->getNumLinks() && "Link accessed out of range!");
+ if (Node->getLink(Link) == 0) {
+ DSNode::NodeTy NT;
+ const Type *Ty;
+
+ switch (Node->getType()->getPrimitiveID()) {
+ case Type::PointerTyID:
+ Ty = cast<PointerType>(Node->getType())->getElementType();
+ NT = DSNode::ShadowNode;
+ break;
+ case Type::ArrayTyID:
+ Ty = cast<ArrayType>(Node->getType())->getElementType();
+ NT = DSNode::SubElement;
+ break;
+ case Type::StructTyID:
+ Ty = cast<StructType>(Node->getType())->getContainedType(Link);
+ NT = DSNode::SubElement;
+ break;
+ default:
+ assert(0 && "Unexpected type to dereference!");
+ abort();
+ }
+
+ DSNode *New = createNode(NT, Ty);
+ Node->addEdgeTo(Link, New);
+ }
+
+ return Node->getLink(Link);
+}
+
+// getSubscriptedNode - Perform the basic getelementptr functionality that must
+// be factored out of gep, load and store while they are all MAI's.
+//
+DSNode *GraphBuilder::getSubscriptedNode(MemAccessInst &MAI, DSNode *Ptr) {
+ for (unsigned i = MAI.getFirstIndexOperandNumber(), e = MAI.getNumOperands();
+ i != e; ++i)
+ if (MAI.getOperand(i)->getType() == Type::UIntTy)
+ Ptr = getLink(Ptr, 0);
+ else if (MAI.getOperand(i)->getType() == Type::UByteTy)
+ Ptr = getLink(Ptr, cast<ConstantUInt>(MAI.getOperand(i))->getValue());
+
+ if (MAI.getFirstIndexOperandNumber() == MAI.getNumOperands())
+ Ptr = getLink(Ptr, 0); // All MAI's have an implicit 0 if nothing else.
+
+ return Ptr;
+}
+
+
+// removeDeadNodes - After the graph has been constructed, this method removes
+// all unreachable nodes that are created because they got merged with other
+// nodes in the graph. These nodes will all be trivially unreachable, so we
+// don't have to perform any non-trivial analysis here.
+//
+void GraphBuilder::removeDeadNodes() {
+ for (unsigned i = 0; i != Nodes.size(); )
+ if (!Nodes[i]->getReferrers().empty())
+ ++i; // This node is alive!
+ else { // This node is dead!
+ delete Nodes[i]; // Free memory...
+ Nodes.erase(Nodes.begin()+i); // Remove from node list...
+ }
+}
+
+
+
+
+//===----------------------------------------------------------------------===//
+// Specific instruction type handler implementations...
+//
+
+// Alloca & Malloc instruction implementation - Simply create a new memory
+// object, pointing the scalar to it.
+//
+void GraphBuilder::handleAlloc(AllocationInst &AI, DSNode::NodeTy NodeType) {
+ DSNode *Scalar = getValueNode(AI);
+ DSNode *New = createNode(NodeType, AI.getAllocatedType());
+ Scalar->addEdgeTo(New); // Make the scalar point to the new node...
+}
+
+// PHINode - Make the scalar for the PHI node point to all of the things the
+// incoming values point to... which effectively causes them to be merged.
+//
+void GraphBuilder::visitPHINode(PHINode &PN) {
+ if (!isa<PointerType>(PN.getType())) return; // Only pointer PHIs
+
+ DSNode *Scalar = getValueNode(PN);
+ for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
+ Scalar->mergeWith(getValueNode(*PN.getIncomingValue(i)));
+}
+
+void GraphBuilder::visitGetElementPtrInst(GetElementPtrInst &GEP) {
+ DSNode *Scalar = getValueNode(GEP);
+ DSNode *Ptr = getSubscriptedNode(GEP, getValueNode(*GEP.getOperand(0)));
+ Scalar->addEdgeTo(Ptr);
+}
+
+void GraphBuilder::visitLoadInst(LoadInst &LI) {
+ if (!isa<PointerType>(LI.getType())) return; // Only pointer PHIs
+ DSNode *Ptr = getSubscriptedNode(LI, getValueNode(*LI.getOperand(0)));
+ getValueNode(LI)->mergeWith(Ptr);
+}
+
+void GraphBuilder::visitStoreInst(StoreInst &SI) {
+ if (!isa<PointerType>(SI.getOperand(0)->getType())) return;
+ DSNode *Value = getValueNode(*SI.getOperand(0));
+ DSNode *DestPtr = getValueNode(*SI.getOperand(1));
+ Value->mergeWith(getSubscriptedNode(SI, DestPtr));
+}
+
+void GraphBuilder::visitReturnInst(ReturnInst &RI) {
+ if (RI.getNumOperands() && isa<PointerType>(RI.getOperand(0)->getType())) {
+ DSNode *Value = getValueNode(*RI.getOperand(0));
+ Value->mergeWith(RetNode);
+ RetNode = Value;
+ }
+}
+
+void GraphBuilder::visitCallInst(CallInst &CI) {
+ FunctionCalls.push_back(vector<DSNodeHandle>());
+ vector<DSNodeHandle> &Args = FunctionCalls.back();
+
+ for (unsigned i = 0, e = CI.getNumOperands(); i != e; ++i)
+ if (isa<PointerType>(CI.getOperand(i)->getType()))
+ Args.push_back(getValueNode(*CI.getOperand(i)));
+}