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llvm-mirror/include/llvm/Analysis/DSGraph.h
Misha Brukman 6ed546e3d2 Doxygenified and cleand up comments.
llvm-svn: 12294
2004-03-11 23:08:20 +00:00

449 lines
17 KiB
C++

//===- 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.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DSGRAPH_H
#define LLVM_ANALYSIS_DSGRAPH_H
#include "llvm/Analysis/DSNode.h"
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<Value*, DSNodeHandle> ValueMapTy;
ValueMapTy ValueMap;
typedef hash_set<GlobalValue*> GlobalSetTy;
GlobalSetTy GlobalSet;
public:
// 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(); }
iterator find(Value *V) { return ValueMap.find(V); }
const_iterator find(Value *V) const { return ValueMap.find(V); }
unsigned count(Value *V) const { return ValueMap.count(V); }
void erase(Value *V) { erase(find(V)); }
/// 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(Value *Old, Value *New) {
iterator I = find(Old);
assert(I != end() && "Old value is not in the map!");
ValueMap.insert(std::make_pair(New, I->second));
erase(I);
}
DSNodeHandle &operator[](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 (GlobalValue *GV = dyn_cast<GlobalValue>(V))
GlobalSet.insert(GV);
}
return IP.first->second;
}
void erase(iterator I) {
assert(I != ValueMap.end() && "Cannot erase end!");
if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first))
GlobalSet.erase(GV);
ValueMap.erase(I);
}
void clear() {
ValueMap.clear();
GlobalSet.clear();
}
// 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(); }
};
//===----------------------------------------------------------------------===//
/// DSGraph - The graph that represents a function.
///
struct DSGraph {
// Public data-type declarations...
typedef DSScalarMap ScalarMapTy;
typedef hash_map<Function*, DSNodeHandle> ReturnNodesTy;
typedef hash_set<GlobalValue*> GlobalSetTy;
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;
private:
DSGraph *GlobalsGraph; // Pointer to the common graph of global objects
bool PrintAuxCalls; // 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 vector 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::vector<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::vector<DSCallSite> AuxFunctionCalls;
// InlinedGlobals - This set records which globals have been inlined from
// other graphs (callers or callees, depending on the pass) into this one.
//
GlobalSetTy InlinedGlobals;
/// TD - This is the target data object for the machine this graph is
/// constructed for.
const TargetData &TD;
void operator=(const DSGraph &); // DO NOT IMPLEMENT
public:
// Create a new, empty, DSGraph.
DSGraph(const TargetData &td)
: GlobalsGraph(0), PrintAuxCalls(false), TD(td) {}
// Compute the local DSGraph
DSGraph(const TargetData &td, Function &F, DSGraph *GlobalsGraph);
// 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(const DSGraph &DSG);
DSGraph(const DSGraph &DSG, NodeMapTy &NodeMap);
~DSGraph();
DSGraph *getGlobalsGraph() const { return GlobalsGraph; }
void setGlobalsGraph(DSGraph *G) { GlobalsGraph = G; }
/// getTargetData - Return the TargetData object for the current target.
///
const TargetData &getTargetData() const { return TD; }
/// setPrintAuxCalls - If you call this method, the auxillary call vector will
/// be printed instead of the standard call vector to the dot file.
///
void setPrintAuxCalls() { PrintAuxCalls = true; }
bool shouldPrintAuxCalls() const { return PrintAuxCalls; }
/// 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::compat_iterator node_iterator;
node_iterator node_begin() const { return Nodes.compat_begin(); }
node_iterator node_end() const { return Nodes.compat_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::vector<DSCallSite> &getFunctionCalls() const {
return FunctionCalls;
}
/// getAuxFunctionCalls - Get the call sites as modified by whatever passes
/// have been run.
///
std::vector<DSCallSite> &getAuxFunctionCalls() {
return AuxFunctionCalls;
}
const std::vector<DSCallSite> &getAuxFunctionCalls() const {
return AuxFunctionCalls;
}
/// getInlinedGlobals - Get the set of globals that are have been inlined
/// (from callees in BU or from callers in TD) into the current graph.
///
GlobalSetTy& getInlinedGlobals() {
return InlinedGlobals;
}
/// 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(Value *V) { return ScalarMap[V]; }
const DSNodeHandle &getNodeForValue(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;
}
/// 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(Function &F) {
ReturnNodesTy::iterator I = ReturnNodes.find(&F);
assert(I != ReturnNodes.end() && "F not in this DSGraph!");
return I->second;
}
const DSNodeHandle &getReturnNodeFor(Function &F) const {
ReturnNodesTy::const_iterator I = ReturnNodes.find(&F);
assert(I != ReturnNodes.end() && "F not in this DSGraph!");
return I->second;
}
/// getGraphSize - Return the number of nodes in this graph.
///
unsigned getGraphSize() const {
return Nodes.size();
}
/// print - Print a dot graph to the specified ostream...
///
void print(std::ostream &O) const;
/// dump - call print(std::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)
(*I)->maskNodeTypes(Mask);
}
void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
// 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,
};
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,
UpdateInlinedGlobals = 1 << 5, DontUpdateInlinedGlobals = 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);
/// cloneInto - Clone the specified DSGraph into the current graph. The
/// translated ScalarMap for the old function is filled into the OldValMap
/// member, and the translated ReturnNodes map is returned into ReturnNodes.
/// OldNodeMap contains a mapping from the original nodes to the newly cloned
/// nodes.
///
/// The CloneFlags member controls various aspects of the cloning process.
///
void cloneInto(const DSGraph &G, ScalarMapTy &OldValMap,
ReturnNodesTy &OldReturnNodes, NodeMapTy &OldNodeMap,
unsigned CloneFlags = 0);
/// mergeInGraph - The method is used for merging graphs together. If the
/// argument graph is not *this, it makes a clone of the specified graph, then
/// merges the nodes specified in the call site with the formal arguments in
/// the graph. If the StripAlloca's argument is 'StripAllocaBit' then Alloca
/// markers are removed from nodes.
///
void mergeInGraph(const DSCallSite &CS, 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(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, GlobalValue *GV) const {
assert(std::find(N->getGlobals().begin(), N->getGlobals().end(), GV) !=
N->getGlobals().end() && "Global value not in node!");
}
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();
};
/// 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;
public:
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 = ~DSNode::DEAD;
if (CloneFlags & DSGraph::StripAllocaBit)
BitsToKeep &= ~DSNode::AllocaNode;
if (CloneFlags & DSGraph::StripModRefBits)
BitsToKeep &= ~(DSNode::Modified | DSNode::Read);
if (CloneFlags & DSGraph::StripIncompleteBit)
BitsToKeep &= ~DSNode::Incomplete;
}
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(const DSCallSite &DestCS, 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
#endif