llvm-6502/include/llvm/Analysis/DSGraph.h
Chris Lattner 9550dc2df2 Add #include
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4291 91177308-0d34-0410-b5e6-96231b3b80d8
2002-10-27 19:08:03 +00:00

607 lines
22 KiB
C++

//===- DSGraph.h - Represent a collection of data structures ----*- C++ -*-===//
//
// This header defines the primative classes that make up a data structure
// graph.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DSGRAPH_H
#define LLVM_ANALYSIS_DSGRAPH_H
#include <vector>
#include <map>
#include <functional>
#include <string>
class Function;
class CallInst;
class Value;
class GlobalValue;
class Type;
class DSNode; // Each node in the graph
class DSGraph; // A graph for a function
class DSNodeIterator; // Data structure graph traversal iterator
//===----------------------------------------------------------------------===//
/// DSNodeHandle - Implement a "handle" to a data structure node that takes care
/// of all of the add/un'refing of the node to prevent the backpointers in the
/// graph from getting out of date. This class represents a "pointer" in the
/// graph, whose destination is an indexed offset into a node.
///
class DSNodeHandle {
DSNode *N;
unsigned Offset;
public:
// Allow construction, destruction, and assignment...
DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
setNode(n);
}
DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
~DSNodeHandle() { setNode((DSNode*)0); }
DSNodeHandle &operator=(const DSNodeHandle &H) {
setNode(H.N); Offset = H.Offset;
return *this;
}
bool operator<(const DSNodeHandle &H) const { // Allow sorting
return N < H.N || (N == H.N && Offset < H.Offset);
}
bool operator>(const DSNodeHandle &H) const { return H < *this; }
bool operator==(const DSNodeHandle &H) const { // Allow comparison
return N == H.N && Offset == H.Offset;
}
bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
// Allow explicit conversion to DSNode...
DSNode *getNode() const { return N; }
unsigned getOffset() const { return Offset; }
inline void setNode(DSNode *N); // Defined inline later...
void setOffset(unsigned O) { Offset = O; }
void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
/// mergeWith - Merge the logical node pointed to by 'this' with the node
/// pointed to by 'N'.
///
void mergeWith(const DSNodeHandle &N);
// hasLink - Return true if there is a link at the specified offset...
inline bool hasLink(unsigned Num) const;
/// getLink - Treat this current node pointer as a pointer to a structure of
/// some sort. This method will return the pointer a mem[this+Num]
///
inline const DSNodeHandle *getLink(unsigned Num) const;
inline DSNodeHandle *getLink(unsigned Num);
inline void setLink(unsigned Num, const DSNodeHandle &NH);
};
//===----------------------------------------------------------------------===//
/// DSNode - Data structure node class
///
/// This class represents an untyped memory object of Size bytes. It keeps
/// track of any pointers that have been stored into the object as well as the
/// different types represented in this object.
///
class DSNode {
/// Links - Contains one entry for every _distinct_ pointer field in the
/// memory block. These are demand allocated and indexed by the MergeMap
/// vector.
///
std::vector<DSNodeHandle> Links;
/// MergeMap - Maps from every byte in the object to a signed byte number.
/// This map is neccesary due to the merging that is possible as part of the
/// unification algorithm. To merge two distinct bytes of the object together
/// into a single logical byte, the indexes for the two bytes are set to the
/// same value. This fully general merging is capable of representing all
/// manners of array merging if neccesary.
///
/// This map is also used to map outgoing pointers to various byte offsets in
/// this data structure node. If this value is >= 0, then it indicates that
/// the numbered entry in the Links vector contains the outgoing edge for this
/// byte offset. In this way, the Links vector can be demand allocated and
/// byte elements of the node may be merged without needing a Link allocated
/// for it.
///
/// Initially, each each element of the MergeMap is assigned a unique negative
/// number, which are then merged as the unification occurs.
///
std::vector<signed char> MergeMap;
/// Referrers - Keep track of all of the node handles that point to this
/// DSNode. These pointers may need to be updated to point to a different
/// node if this node gets merged with it.
///
std::vector<DSNodeHandle*> Referrers;
/// TypeRec - This structure is used to represent a single type that is held
/// in a DSNode.
struct TypeRec {
const Type *Ty; // The type itself...
unsigned Offset; // The offset in the node
bool isArray; // Have we accessed an array of elements?
TypeRec() : Ty(0), Offset(0), isArray(false) {}
TypeRec(const Type *T, unsigned O) : Ty(T), Offset(O), isArray(false) {}
bool operator<(const TypeRec &TR) const {
// Sort first by offset!
return Offset < TR.Offset || (Offset == TR.Offset && Ty < TR.Ty);
}
bool operator==(const TypeRec &TR) const {
return Ty == TR.Ty && Offset == TR.Offset;
}
bool operator!=(const TypeRec &TR) const { return !operator==(TR); }
};
/// TypeEntries - As part of the merging process of this algorithm, nodes of
/// different types can be represented by this single DSNode. This vector is
/// kept sorted.
///
std::vector<TypeRec> TypeEntries;
/// Globals - The list of global values that are merged into this node.
///
std::vector<GlobalValue*> Globals;
void operator=(const DSNode &); // DO NOT IMPLEMENT
public:
enum NodeTy {
ShadowNode = 0, // Nothing is known about this node...
ScalarNode = 1 << 0, // Scalar of the current function contains this value
AllocaNode = 1 << 1, // This node was allocated with alloca
NewNode = 1 << 2, // This node was allocated with malloc
GlobalNode = 1 << 3, // This node was allocated by a global var decl
Incomplete = 1 << 4, // This node may not be complete
Modified = 1 << 5, // This node is modified in this context
Read = 1 << 6, // This node is read in this context
};
/// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
/// to the nodes in the data structure graph, so it is possible to have nodes
/// with a value of 0 for their NodeType. Scalar and Alloca markers go away
/// when function graphs are inlined.
///
unsigned char NodeType;
DSNode(enum NodeTy NT, const Type *T);
DSNode(const DSNode &);
~DSNode() {
#ifndef NDEBUG
dropAllReferences(); // Only needed to satisfy assertion checks...
assert(Referrers.empty() && "Referrers to dead node exist!");
#endif
}
// Iterator for graph interface...
typedef DSNodeIterator iterator;
typedef DSNodeIterator const_iterator;
inline iterator begin() const; // Defined in DSGraphTraits.h
inline iterator end() const;
//===--------------------------------------------------
// Accessors
/// getSize - Return the maximum number of bytes occupied by this object...
///
unsigned getSize() const { return MergeMap.size(); }
// getTypeEntries - Return the possible types and their offsets in this object
const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
/// getReferrers - Return a list of the pointers to this node...
///
const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
/// isModified - Return true if this node may be modified in this context
///
bool isModified() const { return (NodeType & Modified) != 0; }
/// isRead - Return true if this node may be read in this context
///
bool isRead() const { return (NodeType & Read) != 0; }
/// hasLink - Return true if this memory object has a link at the specified
/// location.
///
bool hasLink(unsigned i) const {
assert(i < getSize() && "Field Link index is out of range!");
return MergeMap[i] >= 0;
}
DSNodeHandle *getLink(unsigned i) {
if (hasLink(i))
return &Links[MergeMap[i]];
return 0;
}
const DSNodeHandle *getLink(unsigned i) const {
if (hasLink(i))
return &Links[MergeMap[i]];
return 0;
}
int getMergeMapLabel(unsigned i) const {
assert(i < MergeMap.size() && "MergeMap index out of range!");
return MergeMap[i];
}
/// setLink - Set the link at the specified offset to the specified
/// NodeHandle, replacing what was there. It is uncommon to use this method,
/// instead one of the higher level methods should be used, below.
///
void setLink(unsigned i, const DSNodeHandle &NH);
/// addEdgeTo - Add an edge from the current node to the specified node. This
/// can cause merging of nodes in the graph.
///
void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
/// mergeWith - Merge this node and the specified node, moving all links to
/// and from the argument node into the current node, deleting the node
/// argument. Offset indicates what offset the specified node is to be merged
/// into the current node.
///
/// The specified node may be a null pointer (in which case, nothing happens).
///
void mergeWith(const DSNodeHandle &NH, unsigned Offset);
/// mergeIndexes - If we discover that two indexes are equivalent and must be
/// merged, this function is used to do the dirty work.
///
void mergeIndexes(unsigned idx1, unsigned idx2) {
assert(idx1 < getSize() && idx2 < getSize() && "Indexes out of range!");
signed char MV1 = MergeMap[idx1];
signed char MV2 = MergeMap[idx2];
if (MV1 != MV2)
mergeMappedValues(MV1, MV2);
}
/// addGlobal - Add an entry for a global value to the Globals list. This
/// also marks the node with the 'G' flag if it does not already have it.
///
void addGlobal(GlobalValue *GV);
const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
std::vector<GlobalValue*> &getGlobals() { return Globals; }
void print(std::ostream &O, const DSGraph *G) const;
void dump() const;
void dropAllReferences() {
Links.clear();
}
/// remapLinks - Change all of the Links in the current node according to the
/// specified mapping.
void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
private:
friend class DSNodeHandle;
// addReferrer - Keep the referrer set up to date...
void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
void removeReferrer(DSNodeHandle *H);
/// rewriteMergeMap - Loop over the mergemap, replacing any references to the
/// index From to be references to the index To.
///
void rewriteMergeMap(signed char From, signed char To) {
assert(From != To && "Cannot change something into itself!");
for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
if (MergeMap[i] == From)
MergeMap[i] = To;
}
/// mergeMappedValues - This is the higher level form of rewriteMergeMap. It
/// is fully capable of merging links together if neccesary as well as simply
/// rewriting the map entries.
///
void mergeMappedValues(signed char V1, signed char V2);
};
//===----------------------------------------------------------------------===//
// Define inline DSNodeHandle functions that depend on the definition of DSNode
//
inline void DSNodeHandle::setNode(DSNode *n) {
if (N) N->removeReferrer(this);
N = n;
if (N) N->addReferrer(this);
}
inline bool DSNodeHandle::hasLink(unsigned Num) const {
assert(N && "DSNodeHandle does not point to a node yet!");
return N->hasLink(Num+Offset);
}
/// getLink - Treat this current node pointer as a pointer to a structure of
/// some sort. This method will return the pointer a mem[this+Num]
///
inline const DSNodeHandle *DSNodeHandle::getLink(unsigned Num) const {
assert(N && "DSNodeHandle does not point to a node yet!");
return N->getLink(Num+Offset);
}
inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
assert(N && "DSNodeHandle does not point to a node yet!");
return N->getLink(Num+Offset);
}
inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
assert(N && "DSNodeHandle does not point to a node yet!");
N->setLink(Num+Offset, NH);
}
/// addEdgeTo - Add an edge from the current node to the specified node. This
/// can cause merging of nodes in the graph.
///
inline void DSNodeHandle::addEdgeTo(unsigned LinkNo, const DSNodeHandle &Node) {
assert(N && "DSNodeHandle does not point to a node yet!");
N->addEdgeTo(LinkNo+Offset, Node);
}
/// mergeWith - Merge the logical node pointed to by 'this' with the node
/// pointed to by 'N'.
///
inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
assert(N && "DSNodeHandle does not point to a node yet!");
N->mergeWith(Node, Offset);
}
//===----------------------------------------------------------------------===//
/// DSCallSite - Representation of a call site via its call instruction,
/// the DSNode handle for the callee function (or function pointer), and
/// the DSNode handles for the function arguments.
///
/// One unusual aspect of this callsite record is the ResolvingCaller member.
/// If this is non-null, then it indicates the function that allowed a call-site
/// to finally be resolved. Because of indirect calls, this function may not
/// actually be the function that contains the Call instruction itself. This is
/// used by the BU and TD passes to communicate.
///
class DSCallSite {
CallInst *Inst; // Actual call site
DSNodeHandle RetVal; // Returned value
DSNodeHandle Callee; // The function node called
std::vector<DSNodeHandle> CallArgs; // The pointer arguments
Function *ResolvingCaller; // See comments above
static void InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
const std::map<const DSNode*, DSNode*> &NodeMap) {
if (DSNode *N = Src.getNode()) {
std::map<const DSNode*, DSNode*>::const_iterator I = NodeMap.find(N);
assert(I != NodeMap.end() && "Not not in mapping!");
NH.setOffset(Src.getOffset());
NH.setNode(I->second);
}
}
static void InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
const std::map<const DSNode*, DSNodeHandle> &NodeMap) {
if (DSNode *N = Src.getNode()) {
std::map<const DSNode*, DSNodeHandle>::const_iterator I = NodeMap.find(N);
assert(I != NodeMap.end() && "Not not in mapping!");
NH.setOffset(Src.getOffset()+I->second.getOffset());
NH.setNode(I->second.getNode());
}
}
DSCallSite(); // DO NOT IMPLEMENT
public:
/// Constructor. Note - This ctor destroys the argument vector passed in. On
/// exit, the argument vector is empty.
///
DSCallSite(CallInst &inst, const DSNodeHandle &rv, const DSNodeHandle &callee,
std::vector<DSNodeHandle> &Args)
: Inst(&inst), RetVal(rv), Callee(callee), ResolvingCaller(0) {
Args.swap(CallArgs);
}
DSCallSite(const DSCallSite &DSCS) // Simple copy ctor
: Inst(DSCS.Inst), RetVal(DSCS.RetVal),
Callee(DSCS.Callee), CallArgs(DSCS.CallArgs),
ResolvingCaller(DSCS.ResolvingCaller) {}
/// Mapping copy constructor - This constructor takes a preexisting call site
/// to copy plus a map that specifies how the links should be transformed.
/// This is useful when moving a call site from one graph to another.
///
template<typename MapTy>
DSCallSite(const DSCallSite &FromCall, const MapTy &NodeMap) {
Inst = FromCall.Inst;
InitNH(RetVal, FromCall.RetVal, NodeMap);
InitNH(Callee, FromCall.Callee, NodeMap);
CallArgs.resize(FromCall.CallArgs.size());
for (unsigned i = 0, e = FromCall.CallArgs.size(); i != e; ++i)
InitNH(CallArgs[i], FromCall.CallArgs[i], NodeMap);
ResolvingCaller = FromCall.ResolvingCaller;
}
// Accessor functions...
Function &getCaller() const;
CallInst &getCallInst() const { return *Inst; }
DSNodeHandle &getRetVal() { return RetVal; }
DSNodeHandle &getCallee() { return Callee; }
const DSNodeHandle &getRetVal() const { return RetVal; }
const DSNodeHandle &getCallee() const { return Callee; }
void setCallee(const DSNodeHandle &H) { Callee = H; }
unsigned getNumPtrArgs() const { return CallArgs.size(); }
Function *getResolvingCaller() const { return ResolvingCaller; }
void setResolvingCaller(Function *F) { ResolvingCaller = F; }
DSNodeHandle &getPtrArg(unsigned i) {
assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
return CallArgs[i];
}
const DSNodeHandle &getPtrArg(unsigned i) const {
assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
return CallArgs[i];
}
bool operator<(const DSCallSite &CS) const {
if (RetVal < CS.RetVal) return true;
if (RetVal > CS.RetVal) return false;
if (Callee < CS.Callee) return true;
if (Callee > CS.Callee) return false;
return CallArgs < CS.CallArgs;
}
bool operator==(const DSCallSite &CS) const {
return RetVal == CS.RetVal && Callee == CS.Callee &&
CallArgs == CS.CallArgs;
}
};
//===----------------------------------------------------------------------===//
/// DSGraph - The graph that represents a function.
///
class DSGraph {
Function *Func;
std::vector<DSNode*> Nodes;
DSNodeHandle RetNode; // Node that gets returned...
std::map<Value*, DSNodeHandle> ValueMap;
#if 0
// GlobalsGraph -- Reference to the common graph of globally visible objects.
// This includes GlobalValues, New nodes, Cast nodes, and Calls.
//
GlobalDSGraph* GlobalsGraph;
#endif
// FunctionCalls - This vector maintains a single entry for each call
// instruction in the current graph. Each call entry contains DSNodeHandles
// that refer to the arguments that are passed into the function call. 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.
//
std::vector<DSCallSite> FunctionCalls;
void operator=(const DSGraph &); // DO NOT IMPLEMENT
public:
DSGraph() : Func(0) {} // Create a new, empty, DSGraph.
DSGraph(Function &F); // Compute the local DSGraph
// 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.
DSGraph(const DSGraph &DSG);
DSGraph(const DSGraph &DSG, std::map<const DSNode*, DSNode*> &BUNodeMap);
~DSGraph();
bool hasFunction() const { return Func != 0; }
Function &getFunction() const { return *Func; }
/// getNodes - Get a vector of all the nodes in the graph
///
const std::vector<DSNode*> &getNodes() const { return Nodes; }
std::vector<DSNode*> &getNodes() { return Nodes; }
/// addNode - Add a new node to the graph.
///
void addNode(DSNode *N) { Nodes.push_back(N); }
/// getValueMap - Get a map that describes what the nodes the scalars in this
/// function point to...
///
std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
std::vector<DSCallSite> &getFunctionCalls() {
return FunctionCalls;
}
const std::vector<DSCallSite> &getFunctionCalls() const {
return FunctionCalls;
}
/// 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 ValueMap[V]; }
const DSNodeHandle &getRetNode() const { return RetNode; }
DSNodeHandle &getRetNode() { return RetNode; }
unsigned getGraphSize() const {
return Nodes.size();
}
void print(std::ostream &O) const;
void dump() 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 Scalar or Incomplete.
//
void maskNodeTypes(unsigned char 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.
//
void markIncompleteNodes(bool markFormalArgs = true);
// 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.
//
void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
// removeDeadNodes - Use a more powerful 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.
//
void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
// cloneInto - Clone the specified DSGraph into the current graph, returning
// the Return node of the graph. The translated ValueMap for the old function
// is filled into the OldValMap member.
// If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
// are removed from the graph as the graph is being cloned.
//
DSNodeHandle cloneInto(const DSGraph &G,
std::map<Value*, DSNodeHandle> &OldValMap,
std::map<const DSNode*, DSNode*> &OldNodeMap,
bool StripScalars = false, bool StripAllocas = false);
#if 0
// cloneGlobalInto - Clone the given global node (or the node for the given
// GlobalValue) from the GlobalsGraph and all its target links (recursively).
//
DSNode* cloneGlobalInto(const DSNode* GNode);
DSNode* cloneGlobalInto(GlobalValue* GV) {
assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
}
#endif
private:
bool isNodeDead(DSNode *N);
};
#endif