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//===- DSGraph.h - Represent a collection of data structures ----*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// This header defines the data structure graph (DSGraph) and the
// ReachabilityCloner class.
#include "rdsa/DSNode.h"
#include "llvm/ADT/EquivalenceClasses.h"
#include "poolalloc/ADT/HashExtras.h"
#include <ext/hash_map>
#include <ext/hash_set>
#include <list>
#include <map>
#include <iostream>
namespace llvm {
class GlobalValue;
/// DSScalarMap - An instance of this class is used to keep track of all of
/// which DSNode each scalar in a function points to. This is specialized to
/// keep track of globals with nodes in the function, and to keep track of the
/// unique DSNodeHandle being used by the scalar map.
/// This class is crucial to the efficiency of DSA with some large SCC's. In
/// these cases, the cost of iterating over the scalar map dominates the cost
/// of DSA. In all of these cases, the DSA phase is really trying to identify
/// globals or unique node handles active in the function.
class DSScalarMap {
typedef hash_map<const Value*, DSNodeHandle> ValueMapTy;
ValueMapTy ValueMap;
typedef hash_set<const GlobalValue*> GlobalSetTy;
GlobalSetTy GlobalSet;
EquivalenceClasses<const GlobalValue*> &GlobalECs;
DSScalarMap(EquivalenceClasses<const GlobalValue*> &ECs) : GlobalECs(ECs) {}
EquivalenceClasses<const GlobalValue*> &getGlobalECs() const { return GlobalECs; }
// Compatibility methods: provide an interface compatible with a map of
// Value* to DSNodeHandle's.
typedef ValueMapTy::const_iterator const_iterator;
typedef ValueMapTy::iterator iterator;
iterator begin() { return ValueMap.begin(); }
iterator end() { return ValueMap.end(); }
const_iterator begin() const { return ValueMap.begin(); }
const_iterator end() const { return ValueMap.end(); }
const GlobalValue *getLeaderForGlobal(const GlobalValue *GV) const {
EquivalenceClasses<const GlobalValue*>::iterator ECI = GlobalECs.findValue(GV);
if (ECI == GlobalECs.end()) return GV;
return *GlobalECs.findLeader(ECI);
iterator find(const Value *V) {
iterator I = ValueMap.find(V);
if (I != ValueMap.end()) return I;
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
// If this is a global, check to see if it is equivalenced to something
// in the map.
const GlobalValue *Leader = getLeaderForGlobal(GV);
if (Leader != GV)
I = ValueMap.find((const Value*)Leader);
return I;
const_iterator find(const Value *V) const {
const_iterator I = ValueMap.find(V);
if (I != ValueMap.end()) return I;
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
// If this is a global, check to see if it is equivalenced to something
// in the map.
const GlobalValue *Leader = getLeaderForGlobal(GV);
if (Leader != GV)
I = ValueMap.find((const Value*)Leader);
return I;
/// getRawEntryRef - This method can be used by clients that are aware of the
/// global value equivalence class in effect.
DSNodeHandle &getRawEntryRef(const Value *V) {
std::pair<iterator,bool> IP =
ValueMap.insert(std::make_pair(V, DSNodeHandle()));
if (IP.second) // Inserted the new entry into the map.
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
return IP.first->second;
unsigned count(const Value *V) const { return ValueMap.find(V) != ValueMap.end(); }
void erase(const Value *V) { erase(ValueMap.find(V)); }
void eraseIfExists(const Value *V) {
iterator I = find(V);
if (I != end()) erase(I);
/// replaceScalar - When an instruction needs to be modified, this method can
/// be used to update the scalar map to remove the old and insert the new.
void replaceScalar(const Value *Old, const Value *New) {
iterator I = find(Old);
assert(I != end() && "Old value is not in the map!");
ValueMap.insert(std::make_pair(New, I->second));
/// copyScalarIfExists - If Old exists in the scalar map, make New point to
/// whatever Old did.
void copyScalarIfExists(const Value *Old, const Value *New) {
iterator I = find(Old);
if (I != end())
ValueMap.insert(std::make_pair(New, I->second));
/// operator[] - Return the DSNodeHandle for the specified value, creating a
/// new null handle if there is no entry yet.
DSNodeHandle &operator[](const Value *V) {
iterator I = ValueMap.find(V);
if (I != ValueMap.end())
return I->second; // Return value if already exists.
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
return AddGlobal(GV);
return ValueMap.insert(std::make_pair(V, DSNodeHandle())).first->second;
void erase(iterator I) {
assert(I != ValueMap.end() && "Cannot erase end!");
if (const GlobalValue *GV = dyn_cast<GlobalValue>(I->first))
void clear_scalars() {
unsigned counter = 0;
for(iterator ii = begin(); ii != end(); )
if (isa<GlobalValue>(ii->first))
else {
iterator next = ii;
std::cerr << "Removed " << counter << " scalars in clear_scalars\n";
void clear() {
/// spliceFrom - Copy all entries from RHS, then clear RHS.
void spliceFrom(DSScalarMap &RHS);
// Access to the global set: the set of all globals currently in the
// scalar map.
typedef GlobalSetTy::const_iterator global_iterator;
global_iterator global_begin() const { return GlobalSet.begin(); }
global_iterator global_end() const { return GlobalSet.end(); }
unsigned global_size() const { return GlobalSet.size(); }
unsigned global_count(const GlobalValue *GV) const { return GlobalSet.count(GV); }
DSNodeHandle &AddGlobal(const GlobalValue *GV);
/// DSGraph - The graph that represents a function.
class DSGraph {
// Public data-type declarations...
typedef DSScalarMap ScalarMapTy;
typedef hash_map<const Function*, DSNodeHandle> ReturnNodesTy;
typedef ilist<DSNode> NodeListTy;
/// NodeMapTy - This data type is used when cloning one graph into another to
/// keep track of the correspondence between the nodes in the old and new
/// graphs.
typedef hash_map<const DSNode*, DSNodeHandle> NodeMapTy;
// InvNodeMapTy - This data type is used to represent the inverse of a node
// map.
typedef hash_multimap<DSNodeHandle, const DSNode*> InvNodeMapTy;
DSGraph *GlobalsGraph; // Pointer to the common graph of global objects
bool UseAuxCalls; // Should this graph print the Aux calls vector?
NodeListTy Nodes;
ScalarMapTy ScalarMap;
// ReturnNodes - A return value for every function merged into this graph.
// Each DSGraph may have multiple functions merged into it at any time, which
// is used for representing SCCs.
ReturnNodesTy ReturnNodes;
// FunctionCalls - This list maintains a single entry for each call
// instruction in the current graph. The first entry in the vector is the
// scalar that holds the return value for the call, the second is the function
// scalar being invoked, and the rest are pointer arguments to the function.
// This vector is built by the Local graph and is never modified after that.
std::list<DSCallSite> FunctionCalls;
// AuxFunctionCalls - This vector contains call sites that have been processed
// by some mechanism. In pratice, the BU Analysis uses this vector to hold
// the _unresolved_ call sites, because it cannot modify FunctionCalls.
std::list<DSCallSite> AuxFunctionCalls;
/// TD - This is the target data object for the machine this graph is
/// constructed for.
const DataLayout &TD;
void operator=(const DSGraph &); // DO NOT IMPLEMENT
DSGraph(const DSGraph&); // DO NOT IMPLEMENT
// Create a new, empty, DSGraph.
DSGraph(EquivalenceClasses<const GlobalValue*> &ECs, const DataLayout &td,
DSGraph *GG)
:GlobalsGraph(GG), UseAuxCalls(false),
ScalarMap(ECs), TD(td)
{ }
// Copy ctor - If you want to capture the node mapping between the source and
// destination graph, you may optionally do this by specifying a map to record
// this into.
// Note that a copied graph does not retain the GlobalsGraph pointer of the
// source. You need to set a new GlobalsGraph with the setGlobalsGraph
// method.
DSGraph( DSGraph* DSG, EquivalenceClasses<const GlobalValue*> &ECs,
DSGraph *GG, unsigned CloneFlags);
DSGraph *getGlobalsGraph() const { return GlobalsGraph; }
/// getGlobalECs - Return the set of equivalence classes that the global
/// variables in the program form.
EquivalenceClasses<const GlobalValue*> &getGlobalECs() const {
return ScalarMap.getGlobalECs();
/// getDataLayout - Return the DataLayout object for the current target.
const DataLayout &getDataLayout() const { return TD; }
/// setUseAuxCalls - If you call this method, the auxillary call vector will
/// be printed instead of the standard call vector to the dot file.
void setUseAuxCalls() { UseAuxCalls = true; }
bool shouldUseAuxCalls() const { return UseAuxCalls; }
/// node_iterator/begin/end - Iterate over all of the nodes in the graph. Be
/// extremely careful with these methods because any merging of nodes could
/// cause the node to be removed from this list. This means that if you are
/// iterating over nodes and doing something that could cause _any_ node to
/// merge, your node_iterators into this graph can be invalidated.
typedef NodeListTy::iterator node_iterator;
node_iterator node_begin() { return Nodes.begin(); }
node_iterator node_end() { return Nodes.end(); }
typedef NodeListTy::const_iterator node_const_iterator;
node_const_iterator node_begin() const { return Nodes.begin(); }
node_const_iterator node_end() const { return Nodes.end(); }
/// getFunctionNames - Return a space separated list of the name of the
/// functions in this graph (if any)
std::string getFunctionNames() const;
/// addNode - Add a new node to the graph.
void addNode(DSNode *N) { Nodes.push_back(N); }
void unlinkNode(DSNode *N) { Nodes.remove(N); }
/// getScalarMap - Get a map that describes what the nodes the scalars in this
/// function point to...
ScalarMapTy &getScalarMap() { return ScalarMap; }
const ScalarMapTy &getScalarMap() const { return ScalarMap; }
/// getFunctionCalls - Return the list of call sites in the original local
/// graph...
const std::list<DSCallSite> &getFunctionCalls() const { return FunctionCalls;}
std::list<DSCallSite> &getFunctionCalls() { return FunctionCalls;}
/// getAuxFunctionCalls - Get the call sites as modified by whatever passes
/// have been run.
std::list<DSCallSite> &getAuxFunctionCalls() { return AuxFunctionCalls; }
const std::list<DSCallSite> &getAuxFunctionCalls() const {
return AuxFunctionCalls;
// addAuxFunctionCall - Add a call site to the AuxFunctionCallList
void addAuxFunctionCall(DSCallSite D) { AuxFunctionCalls.push_front(D); }
/// removeFunction - Specify that all call sites to the function have been
/// fully specified by a pass such as StdLibPass.
void removeFunctionCalls(Function& F);
// Function Call iteration
typedef std::list<DSCallSite>::const_iterator fc_iterator;
fc_iterator fc_begin() const { return FunctionCalls.begin(); }
fc_iterator fc_end() const { return FunctionCalls.end(); }
// Aux Function Call iteration
typedef std::list<DSCallSite>::iterator afc_iterator;
afc_iterator afc_begin() { return AuxFunctionCalls.begin(); }
afc_iterator afc_end() { return AuxFunctionCalls.end(); }
typedef std::list<DSCallSite>::const_iterator afc_const_iterator;
afc_const_iterator afc_begin() const { return AuxFunctionCalls.begin(); }
afc_const_iterator afc_end() const { return AuxFunctionCalls.end(); }
/// getNodeForValue - Given a value that is used or defined in the body of the
/// current function, return the DSNode that it points to.
DSNodeHandle &getNodeForValue(const Value *V) { return ScalarMap[V]; }
const DSNodeHandle &getNodeForValue(const Value *V) const {
ScalarMapTy::const_iterator I = ScalarMap.find(V);
assert(I != ScalarMap.end() &&
"Use non-const lookup function if node may not be in the map");
return I->second;
bool hasNodeForValue(const Value* V) const {
ScalarMapTy::const_iterator I = ScalarMap.find(V);
return I != ScalarMap.end();
void eraseNodeForValue(const Value* V) {
/// retnodes_* iterator methods: expose iteration over return nodes in the
/// graph, which are also the set of functions incorporated in this graph.
typedef ReturnNodesTy::const_iterator retnodes_iterator;
retnodes_iterator retnodes_begin() const { return ReturnNodes.begin(); }
retnodes_iterator retnodes_end() const { return ReturnNodes.end(); }
/// getReturnNodes - Return the mapping of functions to their return nodes for
/// this graph.
const ReturnNodesTy &getReturnNodes() const { return ReturnNodes; }
ReturnNodesTy &getReturnNodes() { return ReturnNodes; }
/// getReturnNodeFor - Return the return node for the specified function.
DSNodeHandle &getReturnNodeFor(const Function &F) {
ReturnNodesTy::iterator I = ReturnNodes.find(&F);
assert(I != ReturnNodes.end() && "F not in this DSGraph!");
return I->second;
const DSNodeHandle &getReturnNodeFor(const Function &F) const {
ReturnNodesTy::const_iterator I = ReturnNodes.find(&F);
assert(I != ReturnNodes.end() && "F not in this DSGraph!");
return I->second;
DSNodeHandle& getOrCreateReturnNodeFor(const Function& F) {
return ReturnNodes[&F];
/// containsFunction - Return true if this DSGraph contains information for
/// the specified function.
bool containsFunction(const Function *F) const {
return ReturnNodes.count(F);
/// getGraphSize - Return the number of nodes in this graph.
unsigned getGraphSize() const {
return Nodes.size();
/// addObjectToGraph - This method can be used to add global, stack, and heap
/// objects to the graph. This can be used when updating DSGraphs due to the
/// introduction of new temporary objects. The new object is not pointed to
/// and does not point to any other objects in the graph. Note that this
/// method initializes the type of the DSNode to the declared type of the
/// object if UseDeclaredType is true, otherwise it leaves the node type as
/// void.
DSNode *addObjectToGraph(Value *Ptr, bool UseDeclaredType = true);
/// print - Print a dot graph to the specified ostream...
void print(OStream &O) const {
if ( print(*;
void print(std::ostream &O) const;
/// dump - call print(cerr), for use from the debugger...
void dump() const;
/// viewGraph - Emit a dot graph, run 'dot', run gv on the postscript file,
/// then cleanup. For use from the debugger.
void viewGraph() const;
void writeGraphToFile(std::ostream &O, const std::string &GraphName) const;
/// maskNodeTypes - Apply a mask to all of the node types in the graph. This
/// is useful for clearing out markers like Incomplete.
void maskNodeTypes(unsigned Mask) {
for (node_iterator I = node_begin(), E = node_end(); I != E; ++I)
void maskIncompleteMarkers() { maskNodeTypes(~DSFlags::IncompleteNode); }
// markIncompleteNodes - Traverse the graph, identifying nodes that may be
// modified by other functions that have not been resolved yet. This marks
// nodes that are reachable through three sources of "unknownness":
// Global Variables, Function Calls, and Incoming Arguments
// For any node that may have unknown components (because something outside
// the scope of current analysis may have modified it), the 'Incomplete' flag
// is added to the NodeType.
enum MarkIncompleteFlags {
MarkFormalArgs = 1, IgnoreFormalArgs = 0,
IgnoreGlobals = 2, MarkGlobalsIncomplete = 0,
MarkVAStart = 4
void markIncompleteNodes(unsigned Flags);
// removeDeadNodes - Use a reachability analysis to eliminate subgraphs that
// are unreachable. This often occurs because the data structure doesn't
// "escape" into it's caller, and thus should be eliminated from the caller's
// graph entirely. This is only appropriate to use when inlining graphs.
enum RemoveDeadNodesFlags {
RemoveUnreachableGlobals = 1, KeepUnreachableGlobals = 0
void removeDeadNodes(unsigned Flags);
/// CloneFlags enum - Bits that may be passed into the cloneInto method to
/// specify how to clone the function graph.
enum CloneFlags {
StripAllocaBit = 1 << 0, KeepAllocaBit = 0,
DontCloneCallNodes = 1 << 1, CloneCallNodes = 0,
DontCloneAuxCallNodes = 1 << 2, CloneAuxCallNodes = 0,
StripModRefBits = 1 << 3, KeepModRefBits = 0,
StripIncompleteBit = 1 << 4, KeepIncompleteBit = 0
void updateFromGlobalGraph();
/// computeNodeMapping - Given roots in two different DSGraphs, traverse the
/// nodes reachable from the two graphs, computing the mapping of nodes from
/// the first to the second graph.
static void computeNodeMapping(const DSNodeHandle &NH1,
const DSNodeHandle &NH2, NodeMapTy &NodeMap,
bool StrictChecking = true);
/// computeGToGGMapping - Compute the mapping of nodes in the graph to nodes
/// in the globals graph.
void computeGToGGMapping(NodeMapTy &NodeMap);
/// computeGGToGMapping - Compute the mapping of nodes in the global
/// graph to nodes in this graph.
void computeGGToGMapping(InvNodeMapTy &InvNodeMap);
/// computeCalleeCallerMapping - Given a call from a function in the current
/// graph to the 'Callee' function (which lives in 'CalleeGraph'), compute the
/// mapping of nodes from the callee to nodes in the caller.
void computeCalleeCallerMapping(DSCallSite CS, const Function &Callee,
DSGraph &CalleeGraph, NodeMapTy &NodeMap);
/// spliceFrom - Logically perform the operation of cloning the RHS graph into
/// this graph, then clearing the RHS graph. Instead of performing this as
/// two seperate operations, do it as a single, much faster, one.
void spliceFrom(DSGraph* RHS);
/// cloneInto - Clone the specified DSGraph into the current graph.
/// The CloneFlags member controls various aspects of the cloning process.
void cloneInto(DSGraph* G, unsigned CloneFlags = 0);
/// getFunctionArgumentsForCall - Given a function that is currently in this
/// graph, return the DSNodeHandles that correspond to the pointer-compatible
/// function arguments. The vector is filled in with the return value (or
/// null if it is not pointer compatible), followed by all of the
/// pointer-compatible arguments.
void getFunctionArgumentsForCall(const Function *F,
std::vector<DSNodeHandle> &Args) const;
/// mergeInGraph - This graph merges in the minimal number of
/// nodes from G2 into 'this' graph, merging the bindings specified by the
/// call site (in this graph) with the bindings specified by the vector in G2.
/// If the StripAlloca's argument is 'StripAllocaBit' then Alloca markers are
/// removed from nodes.
void mergeInGraph(const DSCallSite &CS, std::vector<DSNodeHandle> &Args,
const DSGraph &G2, unsigned CloneFlags);
/// mergeInGraph - This method is the same as the above method, but the
/// argument bindings are provided by using the formal arguments of F.
void mergeInGraph(const DSCallSite &CS, const Function &F,
const DSGraph &Graph, unsigned CloneFlags);
/// getCallSiteForArguments - Get the arguments and return value bindings for
/// the specified function in the current graph.
DSCallSite getCallSiteForArguments(const Function &F) const;
/// getDSCallSiteForCallSite - Given an LLVM CallSite object that is live in
/// the context of this graph, return the DSCallSite for it.
DSCallSite getDSCallSiteForCallSite(CallSite CS) const;
// Methods for checking to make sure graphs are well formed...
void AssertNodeInGraph(const DSNode *N) const {
assert((!N || N->getParentGraph() == this) &&
"AssertNodeInGraph: Node is not in graph!");
void AssertNodeContainsGlobal(const DSNode *N, const GlobalValue *GV) const;
void AssertCallSiteInGraph(const DSCallSite &CS) const;
void AssertCallNodesInGraph() const;
void AssertAuxCallNodesInGraph() const;
void AssertGraphOK() const;
/// removeTriviallyDeadNodes - 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. This is used as the first step of
/// removeDeadNodes.
void removeTriviallyDeadNodes(bool updateForwarders = false);
/// ReachabilityCloner - This class is used to incrementally clone and merge
/// nodes from a non-changing source graph into a potentially mutating
/// destination graph. Nodes are only cloned over on demand, either in
/// responds to a merge() or getClonedNH() call. When a node is cloned over,
/// all of the nodes reachable from it are automatically brought over as well.
class ReachabilityCloner {
DSGraph* Dest;
const DSGraph* Src;
/// BitsToKeep - These bits are retained from the source node when the
/// source nodes are merged into the destination graph.
unsigned BitsToKeep;
unsigned CloneFlags;
// NodeMap - A mapping from nodes in the source graph to the nodes that
// represent them in the destination graph.
DSGraph::NodeMapTy NodeMap;
ReachabilityCloner(DSGraph* dest, const DSGraph* src, unsigned cloneFlags)
: Dest(dest), Src(src), CloneFlags(cloneFlags) {
assert(Dest != Src && "Cannot clone from graph to same graph!");
BitsToKeep = ~DSFlags::DeadNode;
if (CloneFlags & DSGraph::StripAllocaBit)
BitsToKeep &= ~DSFlags::AllocaNode;
if (CloneFlags & DSGraph::StripModRefBits)
BitsToKeep &= ~(DSFlags::ModifiedNode | DSFlags::ReadNode);
if (CloneFlags & DSGraph::StripIncompleteBit)
BitsToKeep &= ~DSFlags::IncompleteNode;
DSNodeHandle getClonedNH(const DSNodeHandle &SrcNH);
void merge(const DSNodeHandle &NH, const DSNodeHandle &SrcNH);
/// mergeCallSite - Merge the nodes reachable from the specified src call
/// site into the nodes reachable from DestCS.
void mergeCallSite(DSCallSite &DestCS, const DSCallSite &SrcCS);
DSCallSite cloneCallSite(const DSCallSite& SrcCS);
bool clonedAnyNodes() const { return !NodeMap.empty(); }
/// hasClonedNode - Return true if the specified node has been cloned from
/// the source graph into the destination graph.
bool hasClonedNode(const DSNode *N) {
return NodeMap.count(N);
void destroy() { NodeMap.clear(); }
} // End llvm namespace