mirror of
https://github.com/c64scene-ar/llvm-6502.git
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92673296e6
nodes in the graph are memory objects, which is very nice. This also greatly reduces the size and memory footprint for DSGraphs. For example, the local DSGraph for llu went from 65 to 13 nodes with this change. As a side bonus, dot seems to lay out the graphs slightly better too. :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4488 91177308-0d34-0410-b5e6-96231b3b80d8
407 lines
14 KiB
C++
407 lines
14 KiB
C++
//===- Local.cpp - Compute a local data structure graph for a function ----===//
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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/DSGraph.h"
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#include "llvm/Analysis/DataStructure.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/Function.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/Support/InstVisitor.h"
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#include "llvm/Target/TargetData.h"
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#include "Support/Statistic.h"
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// FIXME: This should eventually be a FunctionPass that is automatically
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// aggregated into a Pass.
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//
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#include "llvm/Module.h"
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using std::map;
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using std::vector;
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static RegisterAnalysis<LocalDataStructures>
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X("datastructure", "Local Data Structure Analysis");
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using namespace DataStructureAnalysis;
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namespace DataStructureAnalysis {
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// FIXME: Do something smarter with target data!
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TargetData TD("temp-td");
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unsigned PointerSize(TD.getPointerSize());
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// isPointerType - Return true if this type is big enough to hold a pointer.
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bool isPointerType(const Type *Ty) {
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if (isa<PointerType>(Ty))
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return true;
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else if (Ty->isPrimitiveType() && Ty->isInteger())
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return Ty->getPrimitiveSize() >= PointerSize;
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return false;
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}
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}
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namespace {
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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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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<DSCallSite> &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<DSCallSite> &fc)
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: G(g), Nodes(nodes), RetNode(retNode), ValueMap(vm), FunctionCalls(fc) {
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// Create scalar nodes for all pointer arguments...
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for (Function::aiterator I = G.getFunction().abegin(),
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E = G.getFunction().aend(); I != E; ++I)
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if (isPointerType(I->getType()))
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getValueDest(*I);
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visit(G.getFunction()); // Single pass over the function
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// Not inlining, only eliminate trivially dead nodes.
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G.removeTriviallyDeadNodes();
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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 visitCastInst(CastInst &CI);
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void visitInstruction(Instruction &I) {}
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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 = 0) {
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DSNode *N = new DSNode(NodeType, Ty); // Create the node
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Nodes.push_back(N); // Add node to nodes list
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return N;
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}
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/// setDestTo - Set the ValueMap entry for the specified value to point to
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/// the specified destination. If the Value already points to a node, make
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/// sure to merge the two destinations together.
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///
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void setDestTo(Value &V, const DSNodeHandle &NH);
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/// getValueDest - Return the DSNode that the actual value points to.
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///
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DSNodeHandle getValueDest(Value &V);
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/// getLink - This method is used to 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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DSNodeHandle &getLink(const DSNodeHandle &Node, unsigned Link = 0);
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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) {
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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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markIncompleteNodes();
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}
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//===----------------------------------------------------------------------===//
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// Helper method implementations...
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//
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/// getValueDest - Return the DSNode that the actual value points to.
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///
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DSNodeHandle GraphBuilder::getValueDest(Value &V) {
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if (Constant *C = dyn_cast<Constant>(&V)) {
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// FIXME: Return null NH for constants like 10 or null
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// FIXME: Handle constant exprs here.
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return 0; // Constant doesn't point to anything.
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}
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DSNodeHandle &NH = ValueMap[&V];
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if (NH.getNode())
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return NH; // Already have a node? Just return it...
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// Otherwise we need to create a new node to point to...
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DSNode *N;
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if (GlobalValue *GV = dyn_cast<GlobalValue>(&V)) {
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// Create a new global node for this global variable...
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N = createNode(DSNode::GlobalNode, GV->getType()->getElementType());
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N->addGlobal(GV);
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} else {
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// Otherwise just create a shadow node
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N = createNode(DSNode::ShadowNode);
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}
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NH.setNode(N); // Remember that we are pointing to it...
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NH.setOffset(0);
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return NH;
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}
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/// getLink - This method is used to 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. We must
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/// specify the type of the Node field we are accessing so that we know what
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/// type should be linked to if we need to create a new node.
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///
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DSNodeHandle &GraphBuilder::getLink(const DSNodeHandle &node, unsigned LinkNo) {
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DSNodeHandle &Node = const_cast<DSNodeHandle&>(node);
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DSNodeHandle *Link = Node.getLink(LinkNo);
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if (Link) return *Link;
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// If the link hasn't been created yet, make and return a new shadow node
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DSNode *N = createNode(DSNode::ShadowNode);
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Node.setLink(LinkNo, N);
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return *Node.getLink(LinkNo);
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}
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/// setDestTo - Set the ValueMap entry for the specified value to point to the
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/// specified destination. If the Value already points to a node, make sure to
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/// merge the two destinations together.
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///
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void GraphBuilder::setDestTo(Value &V, const DSNodeHandle &NH) {
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DSNodeHandle &AINH = ValueMap[&V];
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if (AINH.getNode() == 0) // Not pointing to anything yet?
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AINH = NH; // Just point directly to NH
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else
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AINH.mergeWith(NH);
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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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setDestTo(AI, createNode(NodeType));
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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 (!isPointerType(PN.getType())) return; // Only pointer PHIs
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DSNodeHandle &PNDest = ValueMap[&PN];
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for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
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PNDest.mergeWith(getValueDest(*PN.getIncomingValue(i)));
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}
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void GraphBuilder::visitGetElementPtrInst(GetElementPtrInst &GEP) {
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DSNodeHandle Value = getValueDest(*GEP.getOperand(0));
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if (Value.getNode() == 0) return;
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unsigned Offset = 0;
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const PointerType *PTy = cast<PointerType>(GEP.getOperand(0)->getType());
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const Type *CurTy = PTy->getElementType();
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DSTypeRec &TopTypeRec =
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Value.getNode()->getTypeRec(PTy->getElementType(), Value.getOffset());
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// If the node had to be folded... exit quickly
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if (TopTypeRec.Ty == Type::VoidTy) {
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setDestTo(GEP, Value); // GEP result points to folded node
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return;
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}
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// Handle the pointer index specially...
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if (GEP.getNumOperands() > 1 &&
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GEP.getOperand(1) != ConstantSInt::getNullValue(Type::LongTy)) {
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// If we already know this is an array being accessed, don't do anything...
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if (!TopTypeRec.isArray) {
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TopTypeRec.isArray = true;
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// If we are treating some inner field pointer as an array, fold the node
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// up because we cannot handle it right. This can come because of
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// something like this: &((&Pt->X)[1]) == &Pt->Y
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//
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if (Value.getOffset()) {
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// Value is now the pointer we want to GEP to be...
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Value.getNode()->foldNodeCompletely();
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setDestTo(GEP, Value); // GEP result points to folded node
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return;
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} else {
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// This is a pointer to the first byte of the node. Make sure that we
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// are pointing to the outter most type in the node.
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// FIXME: We need to check one more case here...
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}
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}
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}
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// All of these subscripts are indexing INTO the elements we have...
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for (unsigned i = 2, e = GEP.getNumOperands(); i < e; ++i)
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if (GEP.getOperand(i)->getType() == Type::LongTy) {
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// Get the type indexing into...
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const SequentialType *STy = cast<SequentialType>(CurTy);
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CurTy = STy->getElementType();
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if (ConstantSInt *CS = dyn_cast<ConstantSInt>(GEP.getOperand(i))) {
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Offset += CS->getValue()*TD.getTypeSize(CurTy);
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} else {
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// Variable index into a node. We must merge all of the elements of the
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// sequential type here.
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if (isa<PointerType>(STy))
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std::cerr << "Pointer indexing not handled yet!\n";
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else {
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const ArrayType *ATy = cast<ArrayType>(STy);
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unsigned ElSize = TD.getTypeSize(CurTy);
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DSNode *N = Value.getNode();
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assert(N && "Value must have a node!");
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unsigned RawOffset = Offset+Value.getOffset();
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// Loop over all of the elements of the array, merging them into the
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// zero'th element.
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for (unsigned i = 1, e = ATy->getNumElements(); i != e; ++i)
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// Merge all of the byte components of this array element
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for (unsigned j = 0; j != ElSize; ++j)
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N->mergeIndexes(RawOffset+j, RawOffset+i*ElSize+j);
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}
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}
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} else if (GEP.getOperand(i)->getType() == Type::UByteTy) {
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unsigned FieldNo = cast<ConstantUInt>(GEP.getOperand(i))->getValue();
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const StructType *STy = cast<StructType>(CurTy);
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Offset += TD.getStructLayout(STy)->MemberOffsets[FieldNo];
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CurTy = STy->getContainedType(FieldNo);
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}
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// Add in the offset calculated...
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Value.setOffset(Value.getOffset()+Offset);
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// Value is now the pointer we want to GEP to be...
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setDestTo(GEP, Value);
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}
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void GraphBuilder::visitLoadInst(LoadInst &LI) {
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DSNodeHandle Ptr = getValueDest(*LI.getOperand(0));
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if (Ptr.getNode() == 0) return;
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// Make that the node is read from...
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Ptr.getNode()->NodeType |= DSNode::Read;
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// Ensure a typerecord exists...
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Ptr.getNode()->getTypeRec(LI.getType(), Ptr.getOffset());
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if (isPointerType(LI.getType()))
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setDestTo(LI, getLink(Ptr));
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}
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void GraphBuilder::visitStoreInst(StoreInst &SI) {
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const Type *StoredTy = SI.getOperand(0)->getType();
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DSNodeHandle Dest = getValueDest(*SI.getOperand(1));
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if (Dest.getNode() == 0) return;
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// Make that the node is written to...
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Dest.getNode()->NodeType |= DSNode::Modified;
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// Ensure a typerecord exists...
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Dest.getNode()->getTypeRec(StoredTy, Dest.getOffset());
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// Avoid adding edges from null, or processing non-"pointer" stores
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if (isPointerType(StoredTy))
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Dest.addEdgeTo(getValueDest(*SI.getOperand(0)));
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}
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void GraphBuilder::visitReturnInst(ReturnInst &RI) {
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if (RI.getNumOperands() && isPointerType(RI.getOperand(0)->getType()))
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RetNode.mergeWith(getValueDest(*RI.getOperand(0)));
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}
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void GraphBuilder::visitCallInst(CallInst &CI) {
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// Set up the return value...
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DSNodeHandle RetVal;
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if (isPointerType(CI.getType()))
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RetVal = getValueDest(CI);
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DSNodeHandle Callee = getValueDest(*CI.getOperand(0));
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std::vector<DSNodeHandle> Args;
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Args.reserve(CI.getNumOperands()-1);
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// Calculate the arguments vector...
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for (unsigned i = 1, e = CI.getNumOperands(); i != e; ++i)
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if (isPointerType(CI.getOperand(i)->getType()))
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Args.push_back(getValueDest(*CI.getOperand(i)));
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// Add a new function call entry...
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FunctionCalls.push_back(DSCallSite(CI, RetVal, Callee, Args));
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}
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/// Handle casts...
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void GraphBuilder::visitCastInst(CastInst &CI) {
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if (isPointerType(CI.getType())) {
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if (isPointerType(CI.getOperand(0)->getType()))
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setDestTo(CI, getValueDest(*CI.getOperand(0)));
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else
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; // FIXME: "Other" node
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}
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}
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//===----------------------------------------------------------------------===//
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// LocalDataStructures Implementation
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//===----------------------------------------------------------------------===//
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// releaseMemory - If the pass pipeline is done with this pass, we can release
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// our memory... here...
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//
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void LocalDataStructures::releaseMemory() {
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for (std::map<const Function*, DSGraph*>::iterator I = DSInfo.begin(),
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E = DSInfo.end(); I != E; ++I)
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delete I->second;
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// Empty map so next time memory is released, data structures are not
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// re-deleted.
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DSInfo.clear();
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}
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bool LocalDataStructures::run(Module &M) {
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// Calculate all of the graphs...
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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if (!I->isExternal())
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DSInfo.insert(std::make_pair(I, new DSGraph(*I)));
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return false;
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}
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