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An explicit representation of dependence graphs, and a pass that

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computes a dependence graph for data dependences on memory locations
using interprocedural Mod/Ref information.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4957 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Vikram S. Adve 2002-12-08 13:26:29 +00:00
parent 138b0cd7da
commit 96b21c1054
5 changed files with 1428 additions and 0 deletions
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250
include/llvm/Analysis/DependenceGraph.h Normal file
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//===- DependenceGraph.h - Dependence graph for a function ------*- C++ -*-===//
//
// This file provides an explicit representation for the dependence graph
// of a function, with one node per instruction and one edge per dependence.
// Dependences include both data and control dependences.
//
// Each dep. graph node (class DepGraphNode) keeps lists of incoming and
// outgoing dependence edges.
//
// Each dep. graph edge (class Dependence) keeps a pointer to one end-point
// of the dependence. This saves space and is important because dep. graphs
// can grow quickly. It works just fine because the standard idiom is to
// start with a known node and enumerate the dependences to or from that node.
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_DEPENDENCEGRAPH_H
#define LLVM_ANALYSIS_DEPENDENCEGRAPH_H
#include <Support/NonCopyable.h>
#include <Support/hash_map>
#include <iosfwd>
#include <vector>
#include <utility>
class Instruction;
class Function;
class Dependence;
class DepGraphNode;
class DependenceGraph;
//----------------------------------------------------------------------------
// enum DependenceType: The standard data dependence types.
//----------------------------------------------------------------------------
enum DependenceType {
NoDependence = 0x0,
TrueDependence = 0x1,
AntiDependence = 0x2,
OutputDependence = 0x4,
ControlDependence = 0x8, // from a terminator to some other instr.
IncomingFlag = 0x10 // is this an incoming or outgoing dep?
};
#undef SUPPORTING_LOOP_DEPENDENCES
#ifdef SUPPORTING_LOOP_DEPENDENCES
typedef int DependenceDistance; // negative means unknown distance
typedef short DependenceLevel; // 0 means global level outside loops
#endif
//----------------------------------------------------------------------------
// class Dependence:
//
// A representation of a simple (non-loop-related) dependence.
//----------------------------------------------------------------------------
class Dependence {
DepGraphNode* toOrFromNode;
DependenceType depType:8;
public:
/*ctor*/ Dependence (DepGraphNode* toOrFromN,
DependenceType type,
bool isIncoming)
: toOrFromNode(toOrFromN),
depType(type | (isIncoming? IncomingFlag : 0x0)) { }
/* copy ctor*/ Dependence (const Dependence& D)
: toOrFromNode(D.toOrFromNode),
depType(D.depType) { }
bool operator==(const Dependence& D) {
return toOrFromNode == D.toOrFromNode && depType == D.depType;
}
/// Get information about the type of dependence.
///
DependenceType getDepType() {
return depType;
}
/// Get source or sink depending on what type of node this is!
///
DepGraphNode* getSrc() {
assert(depType & IncomingFlag); return toOrFromNode;
}
const DepGraphNode* getSrc() const {
assert(depType & IncomingFlag); return toOrFromNode;
}
DepGraphNode* getSink() {
assert(! (depType & IncomingFlag)); return toOrFromNode;
}
const DepGraphNode* getSink() const {
assert(! (depType & IncomingFlag)); return toOrFromNode;
}
/// Debugging support methods
///
void print(std::ostream &O) const;
// Default constructor: Do not use directly except for graph builder code
//
/*ctor*/ Dependence() : toOrFromNode(NULL), depType(NoDependence) { }
};
#ifdef SUPPORTING_LOOP_DEPENDENCES
struct LoopDependence: public Dependence {
DependenceDirection dir;
DependenceDistance distance;
DependenceLevel level;
LoopInfo* enclosingLoop;
};
#endif
//----------------------------------------------------------------------------
// class DepGraphNode:
//
// A representation of a single node in a dependence graph, corresponding
// to a single instruction.
//----------------------------------------------------------------------------
class DepGraphNode {
Instruction* instr;
std::vector<Dependence> inDeps;
std::vector<Dependence> outDeps;
friend class DependenceGraph;
typedef std::vector<Dependence>:: iterator iterator;
typedef std::vector<Dependence>::const_iterator const_iterator;
iterator inDepBegin() { return inDeps.begin(); }
const_iterator inDepBegin() const { return inDeps.begin(); }
iterator inDepEnd() { return inDeps.end(); }
const_iterator inDepEnd() const { return inDeps.end(); }
iterator outDepBegin() { return outDeps.begin(); }
const_iterator outDepBegin() const { return outDeps.begin(); }
iterator outDepEnd() { return outDeps.end(); }
const_iterator outDepEnd() const { return outDeps.end(); }
public:
DepGraphNode(Instruction& I) : instr(&I) { }
Instruction& getInstr() { return *instr; }
const Instruction& getInstr() const { return *instr; }
/// Debugging support methods
///
void print(std::ostream &O) const;
};
//----------------------------------------------------------------------------
// class DependenceGraph:
//
// A representation of a dependence graph for a procedure.
// The primary query operation here is to look up a DepGraphNode for
// a particular instruction, and then use the in/out dependence iterators
// for the node.
//----------------------------------------------------------------------------
class DependenceGraph: public NonCopyable {
typedef hash_map<Instruction*, DepGraphNode*> DepNodeMapType;
typedef DepNodeMapType:: iterator map_iterator;
typedef DepNodeMapType::const_iterator const_map_iterator;
DepNodeMapType depNodeMap;
inline DepGraphNode* getNodeInternal(Instruction& inst,
bool createIfMissing = false) {
map_iterator I = depNodeMap.find(&inst);
if (I == depNodeMap.end())
return (!createIfMissing)? NULL :
depNodeMap.insert(
std::make_pair(&inst, new DepGraphNode(inst))).first->second;
else
return I->second;
}
public:
typedef std::vector<Dependence>:: iterator iterator;
typedef std::vector<Dependence>::const_iterator const_iterator;
public:
DependenceGraph() { }
~DependenceGraph();
/// Get the graph node for an instruction. There will be one if and
/// only if there are any dependences incident on this instruction.
/// If there is none, these methods will return NULL.
///
DepGraphNode* getNode(Instruction& inst, bool createIfMissing = false) {
return getNodeInternal(inst, createIfMissing);
}
const DepGraphNode* getNode(const Instruction& inst) const {
return const_cast<DependenceGraph*>(this)
->getNodeInternal(const_cast<Instruction&>(inst));
}
iterator inDepBegin ( DepGraphNode& T) { return T.inDeps.begin(); }
const_iterator inDepBegin (const DepGraphNode& T) const { return T.inDeps.begin(); }
iterator inDepEnd ( DepGraphNode& T) { return T.inDeps.end(); }
const_iterator inDepEnd (const DepGraphNode& T) const { return T.inDeps.end(); }
iterator outDepBegin( DepGraphNode& F) { return F.outDeps.begin();}
const_iterator outDepBegin(const DepGraphNode& F) const { return F.outDeps.begin();}
iterator outDepEnd ( DepGraphNode& F) { return F.outDeps.end(); }
const_iterator outDepEnd (const DepGraphNode& F) const { return F.outDeps.end(); }
/// Debugging support methods
///
void print(const Function& func, std::ostream &O) const;
public:
/// Functions for adding and modifying the dependence graph.
/// These should to be used only by dependence analysis implementations.
void AddSimpleDependence(Instruction& fromI,
Instruction& toI,
DependenceType depType) {
DepGraphNode* fromNode = getNodeInternal(fromI, /*create*/ true);
DepGraphNode* toNode = getNodeInternal(toI, /*create*/ true);
fromNode->outDeps.push_back(Dependence(toNode, depType, false));
toNode-> inDeps. push_back(Dependence(fromNode, depType, true));
}
#ifdef SUPPORTING_LOOP_DEPENDENCES
/// This interface is a placeholder to show what information is needed.
/// It will probably change when it starts being used.
void AddLoopDependence(Instruction& fromI,
Instruction& toI,
DependenceType depType,
DependenceDirection dir,
DependenceDistance distance,
DependenceLevel level,
LoopInfo* enclosingLoop);
#endif // SUPPORTING_LOOP_DEPENDENCES
};
//===----------------------------------------------------------------------===//
#endif

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//===- MemoryDepAnalysis.h - Compute dep graph for memory ops ---*- C++ -*-===//
//
// This file provides a pass (MemoryDepAnalysis) that computes memory-based
// data dependences between instructions for each function in a module.
// Memory-based dependences occur due to load and store operations, but
// also the side-effects of call instructions.
//
// The result of this pass is a DependenceGraph for each function
// representing the memory-based data dependences between instructions.
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_MEMORYDEPANALYSIS_H
#define LLVM_ANALYSIS_MEMORYDEPANALYSIS_H
#include "llvm/Analysis/DependenceGraph.h"
#include "llvm/Analysis/IPModRef.h"
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Pass.h"
#include "Support/TarjanSCCIterator.h"
#include "Support/NonCopyable.h"
#include "Support/hash_map"
class Instruction;
class Function;
class DSGraph;
class ModRefTable;
///---------------------------------------------------------------------------
/// class MemoryDepGraph:
/// Dependence analysis for load/store/call instructions using IPModRef info
/// computed at the granularity of individual DSGraph nodes.
///
/// This pass computes memory dependences for each function in a module.
/// It can be made a FunctionPass once a Pass (such as Parallelize) is
/// allowed to use a FunctionPass such as this one.
///---------------------------------------------------------------------------
class MemoryDepAnalysis: /* Use if FunctionPass: public DependenceGraph, */
public Pass {
/// The following map and depGraph pointer are temporary until this class
/// becomes a FunctionPass instead of a module Pass. */
hash_map<Function*, DependenceGraph*> funcMap;
DependenceGraph* funcDepGraph;
/// Information about one function being analyzed.
const DSGraph* funcGraph;
const FunctionModRefInfo* funcModRef;
/// Internal routine that processes each SCC of the CFG.
void MemoryDepAnalysis::ProcessSCC(SCC<Function*>& S,
ModRefTable& ModRefAfter);
friend class PgmDependenceGraph;
public:
MemoryDepAnalysis()
: /*DependenceGraph(),*/ funcDepGraph(NULL),
funcGraph(NULL), funcModRef(NULL) { }
~MemoryDepAnalysis();
///------------------------------------------------------------------------
/// TEMPORARY FUNCTIONS TO MAKE THIS A MODULE PASS ---
/// These functions will go away once this class becomes a FunctionPass.
/// Driver function to compute dependence graphs for every function.
bool run(Module& M);
/// getGraph() -- Retrieve the dependence graph for a function.
/// This is temporary and will go away once this is a FunctionPass.
/// At that point, this class should directly inherit from DependenceGraph.
///
DependenceGraph& getGraph(Function& F) {
hash_map<Function*, DependenceGraph*>::iterator I = funcMap.find(&F);
assert(I != funcMap.end());
return *I->second;
}
const DependenceGraph& getGraph(Function& F) const {
hash_map<Function*, DependenceGraph*>::const_iterator
I = funcMap.find(&F);
assert(I != funcMap.end());
return *I->second;
}
/// Release depGraphs held in the Function -> DepGraph map.
///
virtual void releaseMemory();
///----END TEMPORARY FUNCTIONS---------------------------------------------
/// Driver functions to compute the Load/Store Dep. Graph per function.
///
bool runOnFunction(Function& _func);
/// getAnalysisUsage - This does not modify anything.
/// It uses the Top-Down DS Graph and IPModRef.
///
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<TDDataStructures>();
AU.addRequired<IPModRef>();
}
/// Debugging support methods
///
void print(std::ostream &O) const;
void dump() const;
};
//===----------------------------------------------------------------------===//
#endif

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//===- MemoryDepAnalysis.cpp - Compute dep graph for memory ops --*-C++-*--===//
//
// This file implements a pass (MemoryDepAnalysis) that computes memory-based
// data dependences between instructions for each function in a module.
// Memory-based dependences occur due to load and store operations, but
// also the side-effects of call instructions.
//
// The result of this pass is a DependenceGraph for each function
// representing the memory-based data dependences between instructions.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/MemoryDepAnalysis.h"
#include "llvm/Analysis/IPModRef.h"
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
#include "llvm/iMemory.h"
#include "llvm/iOther.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/CFG.h"
#include "Support/TarjanSCCIterator.h"
#include "Support/Statistic.h"
#include "Support/NonCopyable.h"
#include "Support/STLExtras.h"
#include "Support/hash_map"
#include "Support/hash_set"
#include <iostream>
///--------------------------------------------------------------------------
/// struct ModRefTable:
///
/// A data structure that tracks ModRefInfo for instructions:
/// -- modRefMap is a map of Instruction* -> ModRefInfo for the instr.
/// -- definers is a vector of instructions that define any node
/// -- users is a vector of instructions that reference any node
/// -- numUsersBeforeDef is a vector indicating that the number of users
/// seen before definers[i] is numUsersBeforeDef[i].
///
/// numUsersBeforeDef[] effectively tells us the exact interleaving of
/// definers and users within the ModRefTable.
/// This is only maintained when constructing the table for one SCC, and
/// not copied over from one table to another since it is no longer useful.
///--------------------------------------------------------------------------
struct ModRefTable
{
typedef hash_map<Instruction*, ModRefInfo> ModRefMap;
typedef ModRefMap::const_iterator const_map_iterator;
typedef ModRefMap:: iterator map_iterator;
typedef std::vector<Instruction*>::const_iterator const_ref_iterator;
typedef std::vector<Instruction*>:: iterator ref_iterator;
ModRefMap modRefMap;
std::vector<Instruction*> definers;
std::vector<Instruction*> users;
std::vector<unsigned> numUsersBeforeDef;
// Iterators to enumerate all the defining instructions
const_ref_iterator defsBegin() const { return definers.begin(); }
ref_iterator defsBegin() { return definers.begin(); }
const_ref_iterator defsEnd() const { return definers.end(); }
ref_iterator defsEnd() { return definers.end(); }
// Iterators to enumerate all the user instructions
const_ref_iterator usersBegin() const { return users.begin(); }
ref_iterator usersBegin() { return users.begin(); }
const_ref_iterator usersEnd() const { return users.end(); }
ref_iterator usersEnd() { return users.end(); }
// Iterator identifying the last user that was seen *before* a
// specified def. In particular, all users in the half-closed range
// [ usersBegin(), usersBeforeDef_End(defPtr) )
// were seen *before* the specified def. All users in the half-closed range
// [ usersBeforeDef_End(defPtr), usersEnd() )
// were seen *after* the specified def.
//
ref_iterator usersBeforeDef_End(const_ref_iterator defPtr) {
unsigned defIndex = (unsigned) (defPtr - defsBegin());
assert(defIndex < numUsersBeforeDef.size());
assert(usersBegin() + numUsersBeforeDef[defIndex] <= usersEnd());
return usersBegin() + numUsersBeforeDef[defIndex];
}
const_ref_iterator usersBeforeDef_End(const_ref_iterator defPtr) const {
return const_cast<ModRefTable*>(this)->usersBeforeDef_End(defPtr);
}
//
// Modifier methods
//
void AddDef(Instruction* D) {
definers.push_back(D);
numUsersBeforeDef.push_back(users.size());
}
void AddUse(Instruction* U) {
users.push_back(U);
}
void Insert(const ModRefTable& fromTable) {
modRefMap.insert(fromTable.modRefMap.begin(), fromTable.modRefMap.end());
definers.insert(definers.end(),
fromTable.definers.begin(), fromTable.definers.end());
users.insert(users.end(),
fromTable.users.begin(), fromTable.users.end());
numUsersBeforeDef.clear(); /* fromTable.numUsersBeforeDef is ignored */
}
};
///--------------------------------------------------------------------------
/// class ModRefInfoBuilder:
///
/// A simple InstVisitor<> class that retrieves the Mod/Ref info for
/// Load/Store/Call instructions and inserts this information in
/// a ModRefTable. It also records all instructions that Mod any node
/// and all that use any node.
///--------------------------------------------------------------------------
class ModRefInfoBuilder: public InstVisitor<ModRefInfoBuilder>,
public NonCopyable
{
const DSGraph& funcGraph;
const FunctionModRefInfo& funcModRef;
ModRefTable& modRefTable;
ModRefInfoBuilder(); // do not implement
public:
/*ctor*/ ModRefInfoBuilder(const DSGraph& _funcGraph,
const FunctionModRefInfo& _funcModRef,
ModRefTable& _modRefTable)
: funcGraph(_funcGraph), funcModRef(_funcModRef), modRefTable(_modRefTable)
{
}
// At a call instruction, retrieve the ModRefInfo using IPModRef results.
// Add the call to the defs list if it modifies any nodes and to the uses
// list if it refs any nodes.
//
void visitCallInst (CallInst& callInst) {
ModRefInfo safeModRef(funcGraph.getGraphSize());
const ModRefInfo* callModRef = funcModRef.getModRefInfo(callInst);
if (callModRef == NULL)
{ // call to external/unknown function: mark all nodes as Mod and Ref
safeModRef.getModSet().set();
safeModRef.getRefSet().set();
callModRef = &safeModRef;
}
modRefTable.modRefMap.insert(std::make_pair(&callInst,
ModRefInfo(*callModRef)));
if (callModRef->getModSet().any())
modRefTable.AddDef(&callInst);
if (callModRef->getRefSet().any())
modRefTable.AddUse(&callInst);
}
// At a store instruction, add to the mod set the single node pointed to
// by the pointer argument of the store. Interestingly, if there is no
// such node, that would be a null pointer reference!
void visitStoreInst (StoreInst& storeInst) {
const DSNodeHandle& ptrNode =
funcGraph.getNodeForValue(storeInst.getPointerOperand());
if (const DSNode* target = ptrNode.getNode())
{
unsigned nodeId = funcModRef.getNodeId(target);
ModRefInfo& minfo =
modRefTable.modRefMap.insert(
std::make_pair(&storeInst,
ModRefInfo(funcGraph.getGraphSize()))).first->second;
minfo.setNodeIsMod(nodeId);
modRefTable.AddDef(&storeInst);
}
else
std::cerr << "Warning: Uninitialized pointer reference!\n";
}
// At a load instruction, add to the ref set the single node pointed to
// by the pointer argument of the load. Interestingly, if there is no
// such node, that would be a null pointer reference!
void visitLoadInst (LoadInst& loadInst) {
const DSNodeHandle& ptrNode =
funcGraph.getNodeForValue(loadInst.getPointerOperand());
if (const DSNode* target = ptrNode.getNode())
{
unsigned nodeId = funcModRef.getNodeId(target);
ModRefInfo& minfo =
modRefTable.modRefMap.insert(
std::make_pair(&loadInst,
ModRefInfo(funcGraph.getGraphSize()))).first->second;
minfo.setNodeIsRef(nodeId);
modRefTable.AddUse(&loadInst);
}
else
std::cerr << "Warning: Uninitialized pointer reference!\n";
}
};
//----------------------------------------------------------------------------
// class MemoryDepAnalysis: A dep. graph for load/store/call instructions
//----------------------------------------------------------------------------
/// Basic dependence gathering algorithm, using TarjanSCCIterator on CFG:
///
/// for every SCC S in the CFG in PostOrder on the SCC DAG
/// {
/// for every basic block BB in S in *postorder*
/// for every instruction I in BB in reverse
/// Add (I, ModRef[I]) to ModRefCurrent
/// if (Mod[I] != NULL)
/// Add I to DefSetCurrent: { I \in S : Mod[I] != NULL }
/// if (Ref[I] != NULL)
/// Add I to UseSetCurrent: { I : Ref[I] != NULL }
///
/// for every def D in DefSetCurrent
///
/// // NOTE: D comes after itself iff S contains a loop
/// if (HasLoop(S) && D & D)
/// Add output-dep: D -> D2
///
/// for every def D2 *after* D in DefSetCurrent
/// // NOTE: D2 comes before D in execution order
/// if (D & D2)
/// Add output-dep: D2 -> D
/// if (HasLoop(S))
/// Add output-dep: D -> D2
///
/// for every use U in UseSetCurrent that was seen *before* D
/// // NOTE: U comes after D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add true-dep: D -> U
/// if (HasLoop(S))
/// Add anti-dep: U -> D
///
/// for every use U in UseSetCurrent that was seen *after* D
/// // NOTE: U comes before D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add anti-dep: U -> D
/// if (HasLoop(S))
/// Add true-dep: D -> U
///
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after D in execution order
/// if (Dnext & D)
/// Add output-dep: D -> Dnext
///
/// for every use Unext in UseSetAfter
/// // NOTE: Unext comes after D in execution order
/// if (Unext & D)
/// Add true-dep: D -> Unext
///
/// for every use U in UseSetCurrent
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after U in execution order
/// if (Dnext & D)
/// Add anti-dep: U -> Dnext
///
/// Add ModRefCurrent to ModRefAfter: { (I, ModRef[I] ) }
/// Add DefSetCurrent to DefSetAfter: { I : Mod[I] != NULL }
/// Add UseSetCurrent to UseSetAfter: { I : Ref[I] != NULL }
/// }
///
///
void MemoryDepAnalysis::ProcessSCC(SCC<Function*>& S,
ModRefTable& ModRefAfter)
{
ModRefTable ModRefCurrent;
ModRefTable::ModRefMap& mapCurrent = ModRefCurrent.modRefMap;
ModRefTable::ModRefMap& mapAfter = ModRefAfter.modRefMap;
bool hasLoop = S.HasLoop();
// Builder class fills out a ModRefTable one instruction at a time.
// To use it, we just invoke it's visit function for each basic block:
//
// for each basic block BB in the SCC in *postorder*
// for each instruction I in BB in *reverse*
// ModRefInfoBuilder::visit(I)
// : Add (I, ModRef[I]) to ModRefCurrent.modRefMap
// : Add I to ModRefCurrent.definers if it defines any node
// : Add I to ModRefCurrent.users if it uses any node
//
ModRefInfoBuilder builder(*funcGraph, *funcModRef, ModRefCurrent);
for (SCC<Function*>::iterator BI=S.begin(), BE=S.end(); BI != BE; ++BI)
// Note: BBs in the SCC<> created by TarjanSCCIterator are in postorder.
for (BasicBlock::reverse_iterator II=(*BI)->rbegin(), IE=(*BI)->rend();
II != IE; ++II)
builder.visit(*II);
/// for every def D in DefSetCurrent
///
for (ModRefTable::ref_iterator II=ModRefCurrent.defsBegin(),
IE=ModRefCurrent.defsEnd(); II != IE; ++II)
{
/// // NOTE: D comes after itself iff S contains a loop
/// if (HasLoop(S))
/// Add output-dep: D -> D2
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **II, OutputDependence);
/// for every def D2 *after* D in DefSetCurrent
/// // NOTE: D2 comes before D in execution order
/// if (D2 & D)
/// Add output-dep: D2 -> D
/// if (HasLoop(S))
/// Add output-dep: D -> D2
for (ModRefTable::ref_iterator JI=II+1; JI != IE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getModSet()))
{
funcDepGraph->AddSimpleDependence(**JI, **II, OutputDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, OutputDependence);
}
/// for every use U in UseSetCurrent that was seen *before* D
/// // NOTE: U comes after D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add true-dep: U -> D
/// if (HasLoop(S))
/// Add anti-dep: D -> U
ModRefTable::ref_iterator JI=ModRefCurrent.usersBegin();
ModRefTable::ref_iterator JE = ModRefCurrent.usersBeforeDef_End(II);
for ( ; JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getRefSet()))
{
if (*II != *JI || hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**JI, **II, AntiDependence);
}
/// for every use U in UseSetCurrent that was seen *after* D
/// // NOTE: U comes before D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add anti-dep: U -> D
/// if (HasLoop(S))
/// Add true-dep: D -> U
for (/*continue JI*/ JE = ModRefCurrent.usersEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getRefSet()))
{
if (*II != *JI || hasLoop)
funcDepGraph->AddSimpleDependence(**JI, **II, AntiDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
}
/// for every def Dnext in DefSetPrev
/// // NOTE: Dnext comes after D in execution order
/// if (Dnext & D)
/// Add output-dep: D -> Dnext
for (ModRefTable::ref_iterator JI=ModRefAfter.defsBegin(),
JE=ModRefAfter.defsEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapAfter.find(*JI)->second.getModSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, OutputDependence);
/// for every use Unext in UseSetAfter
/// // NOTE: Unext comes after D in execution order
/// if (Unext & D)
/// Add true-dep: D -> Unext
for (ModRefTable::ref_iterator JI=ModRefAfter.usersBegin(),
JE=ModRefAfter.usersEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapAfter.find(*JI)->second.getRefSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
}
///
/// for every use U in UseSetCurrent
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after U in execution order
/// if (Dnext & D)
/// Add anti-dep: U -> Dnext
for (ModRefTable::ref_iterator II=ModRefCurrent.usersBegin(),
IE=ModRefCurrent.usersEnd(); II != IE; ++II)
for (ModRefTable::ref_iterator JI=ModRefAfter.defsBegin(),
JE=ModRefAfter.defsEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getRefSet(),
mapAfter.find(*JI)->second.getModSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, AntiDependence);
/// Add ModRefCurrent to ModRefAfter: { (I, ModRef[I] ) }
/// Add DefSetCurrent to DefSetAfter: { I : Mod[I] != NULL }
/// Add UseSetCurrent to UseSetAfter: { I : Ref[I] != NULL }
ModRefAfter.Insert(ModRefCurrent);
}
/// Debugging support methods
///
void MemoryDepAnalysis::print(std::ostream &O) const
{
// TEMPORARY LOOP
for (hash_map<Function*, DependenceGraph*>::const_iterator
I = funcMap.begin(), E = funcMap.end(); I != E; ++I)
{
Function* func = I->first;
DependenceGraph* depGraph = I->second;
O << "\n================================================================\n";
O << "DEPENDENCE GRAPH FOR MEMORY OPERATIONS IN FUNCTION " << func->getName();
O << "\n================================================================\n\n";
depGraph->print(*func, O);
}
}
///
/// Run the pass on a function
///
bool MemoryDepAnalysis::runOnFunction(Function& func)
{
assert(! func.isExternal());
// Get the FunctionModRefInfo holding IPModRef results for this function.
// Use the TD graph recorded within the FunctionModRefInfo object, which
// may not be the same as the original TD graph computed by DS analysis.
//
funcModRef = &getAnalysis<IPModRef>().getFunctionModRefInfo(func);
funcGraph = &funcModRef->getFuncGraph();
// TEMPORARY: ptr to depGraph (later just becomes "this").
assert(funcMap.find(&func) == funcMap.end() && "Analyzing function twice?");
funcDepGraph = funcMap[&func] = new DependenceGraph();
ModRefTable ModRefAfter;
SCC<Function*>* nextSCC;
for (TarjanSCC_iterator<Function*> tarjSCCiter = tarj_begin(&func);
(nextSCC = *tarjSCCiter) != NULL; ++tarjSCCiter)
ProcessSCC(*nextSCC, ModRefAfter);
return true;
}
//-------------------------------------------------------------------------
// TEMPORARY FUNCTIONS TO MAKE THIS A MODULE PASS ---
// These functions will go away once this class becomes a FunctionPass.
//
// Driver function to compute dependence graphs for every function.
// This is temporary and will go away once this is a FunctionPass.
//
bool MemoryDepAnalysis::run(Module& M)
{
for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
if (! FI->isExternal())
runOnFunction(*FI); // automatically inserts each depGraph into funcMap
return true;
}
// Release all the dependence graphs in the map.
void MemoryDepAnalysis::releaseMemory()
{
for (hash_map<Function*, DependenceGraph*>::const_iterator
I = funcMap.begin(), E = funcMap.end(); I != E; ++I)
delete I->second;
funcMap.clear();
// Clear pointers because the pass constructor will not be invoked again.
funcDepGraph = NULL;
funcGraph = NULL;
funcModRef = NULL;
}
MemoryDepAnalysis::~MemoryDepAnalysis()
{
releaseMemory();
}
//----END TEMPORARY FUNCTIONS----------------------------------------------
void MemoryDepAnalysis::dump() const
{
this->print(std::cerr);
}
static RegisterAnalysis<MemoryDepAnalysis>
Z("memdep", "Memory Dependence Analysis");

79
lib/Analysis/IPA/DependenceGraph.cpp Normal file
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//===- DependenceGraph.cpp - Dependence graph for a function ----*- C++ -*-===//
//
// This file implments an explicit representation for the dependence graph
// of a function, with one node per instruction and one edge per dependence.
// Dependences include both data and control dependences.
//
// Each dep. graph node (class DepGraphNode) keeps lists of incoming and
// outgoing dependence edges.
//
// Each dep. graph edge (class Dependence) keeps a pointer to one end-point
// of the dependence. This saves space and is important because dep. graphs
// can grow quickly. It works just fine because the standard idiom is to
// start with a known node and enumerate the dependences to or from that node.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DependenceGraph.h"
#include "llvm/Function.h"
#include "llvm/BasicBlock.h"
#include "llvm/Instruction.h"
//----------------------------------------------------------------------------
// class Dependence:
//
// A representation of a simple (non-loop-related) dependence
//----------------------------------------------------------------------------
void Dependence::print(std::ostream &O) const
{
assert(depType != NoDependence && "This dependence should never be created!");
switch (depType) {
case TrueDependence: O << "TRUE dependence"; break;
case AntiDependence: O << "ANTI dependence"; break;
case OutputDependence: O << "OUTPUT dependence"; break;
case ControlDependence: O << "CONTROL dependence"; break;
default: assert(0 && "Invalid dependence type"); break;
}
}
//----------------------------------------------------------------------------
// class DepGraphNode
//----------------------------------------------------------------------------
void DepGraphNode::print(std::ostream &O) const
{
const_iterator DI = outDepBegin(), DE = outDepEnd();
O << "\nDeps. from instr:" << getInstr();
for ( ; DI != DE; ++DI)
{
O << "\t";
DI->print(O);
O << " to instruction:";
O << DI->getSink()->getInstr();
}
}
//----------------------------------------------------------------------------
// class DependenceGraph
//----------------------------------------------------------------------------
DependenceGraph::~DependenceGraph()
{
// Free all DepGraphNode objects created for this graph
for (map_iterator I = depNodeMap.begin(), E = depNodeMap.end(); I != E; ++I)
delete I->second;
}
void DependenceGraph::print(const Function& func, std::ostream &O) const
{
O << "DEPENDENCE GRAPH FOR FUNCTION " << func.getName() << ":\n";
for (Function::const_iterator BB=func.begin(), FE=func.end(); BB != FE; ++BB)
for (BasicBlock::const_iterator II=BB->begin(), IE=BB->end(); II !=IE; ++II)
if (const DepGraphNode* dgNode = this->getNode(*II))
dgNode->print(O);
}

492
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//===- MemoryDepAnalysis.cpp - Compute dep graph for memory ops --*-C++-*--===//
//
// This file implements a pass (MemoryDepAnalysis) that computes memory-based
// data dependences between instructions for each function in a module.
// Memory-based dependences occur due to load and store operations, but
// also the side-effects of call instructions.
//
// The result of this pass is a DependenceGraph for each function
// representing the memory-based data dependences between instructions.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/MemoryDepAnalysis.h"
#include "llvm/Analysis/IPModRef.h"
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
#include "llvm/iMemory.h"
#include "llvm/iOther.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/CFG.h"
#include "Support/TarjanSCCIterator.h"
#include "Support/Statistic.h"
#include "Support/NonCopyable.h"
#include "Support/STLExtras.h"
#include "Support/hash_map"
#include "Support/hash_set"
#include <iostream>
///--------------------------------------------------------------------------
/// struct ModRefTable:
///
/// A data structure that tracks ModRefInfo for instructions:
/// -- modRefMap is a map of Instruction* -> ModRefInfo for the instr.
/// -- definers is a vector of instructions that define any node
/// -- users is a vector of instructions that reference any node
/// -- numUsersBeforeDef is a vector indicating that the number of users
/// seen before definers[i] is numUsersBeforeDef[i].
///
/// numUsersBeforeDef[] effectively tells us the exact interleaving of
/// definers and users within the ModRefTable.
/// This is only maintained when constructing the table for one SCC, and
/// not copied over from one table to another since it is no longer useful.
///--------------------------------------------------------------------------
struct ModRefTable
{
typedef hash_map<Instruction*, ModRefInfo> ModRefMap;
typedef ModRefMap::const_iterator const_map_iterator;
typedef ModRefMap:: iterator map_iterator;
typedef std::vector<Instruction*>::const_iterator const_ref_iterator;
typedef std::vector<Instruction*>:: iterator ref_iterator;
ModRefMap modRefMap;
std::vector<Instruction*> definers;
std::vector<Instruction*> users;
std::vector<unsigned> numUsersBeforeDef;
// Iterators to enumerate all the defining instructions
const_ref_iterator defsBegin() const { return definers.begin(); }
ref_iterator defsBegin() { return definers.begin(); }
const_ref_iterator defsEnd() const { return definers.end(); }
ref_iterator defsEnd() { return definers.end(); }
// Iterators to enumerate all the user instructions
const_ref_iterator usersBegin() const { return users.begin(); }
ref_iterator usersBegin() { return users.begin(); }
const_ref_iterator usersEnd() const { return users.end(); }
ref_iterator usersEnd() { return users.end(); }
// Iterator identifying the last user that was seen *before* a
// specified def. In particular, all users in the half-closed range
// [ usersBegin(), usersBeforeDef_End(defPtr) )
// were seen *before* the specified def. All users in the half-closed range
// [ usersBeforeDef_End(defPtr), usersEnd() )
// were seen *after* the specified def.
//
ref_iterator usersBeforeDef_End(const_ref_iterator defPtr) {
unsigned defIndex = (unsigned) (defPtr - defsBegin());
assert(defIndex < numUsersBeforeDef.size());
assert(usersBegin() + numUsersBeforeDef[defIndex] <= usersEnd());
return usersBegin() + numUsersBeforeDef[defIndex];
}
const_ref_iterator usersBeforeDef_End(const_ref_iterator defPtr) const {
return const_cast<ModRefTable*>(this)->usersBeforeDef_End(defPtr);
}
//
// Modifier methods
//
void AddDef(Instruction* D) {
definers.push_back(D);
numUsersBeforeDef.push_back(users.size());
}
void AddUse(Instruction* U) {
users.push_back(U);
}
void Insert(const ModRefTable& fromTable) {
modRefMap.insert(fromTable.modRefMap.begin(), fromTable.modRefMap.end());
definers.insert(definers.end(),
fromTable.definers.begin(), fromTable.definers.end());
users.insert(users.end(),
fromTable.users.begin(), fromTable.users.end());
numUsersBeforeDef.clear(); /* fromTable.numUsersBeforeDef is ignored */
}
};
///--------------------------------------------------------------------------
/// class ModRefInfoBuilder:
///
/// A simple InstVisitor<> class that retrieves the Mod/Ref info for
/// Load/Store/Call instructions and inserts this information in
/// a ModRefTable. It also records all instructions that Mod any node
/// and all that use any node.
///--------------------------------------------------------------------------
class ModRefInfoBuilder: public InstVisitor<ModRefInfoBuilder>,
public NonCopyable
{
const DSGraph& funcGraph;
const FunctionModRefInfo& funcModRef;
ModRefTable& modRefTable;
ModRefInfoBuilder(); // do not implement
public:
/*ctor*/ ModRefInfoBuilder(const DSGraph& _funcGraph,
const FunctionModRefInfo& _funcModRef,
ModRefTable& _modRefTable)
: funcGraph(_funcGraph), funcModRef(_funcModRef), modRefTable(_modRefTable)
{
}
// At a call instruction, retrieve the ModRefInfo using IPModRef results.
// Add the call to the defs list if it modifies any nodes and to the uses
// list if it refs any nodes.
//
void visitCallInst (CallInst& callInst) {
ModRefInfo safeModRef(funcGraph.getGraphSize());
const ModRefInfo* callModRef = funcModRef.getModRefInfo(callInst);
if (callModRef == NULL)
{ // call to external/unknown function: mark all nodes as Mod and Ref
safeModRef.getModSet().set();
safeModRef.getRefSet().set();
callModRef = &safeModRef;
}
modRefTable.modRefMap.insert(std::make_pair(&callInst,
ModRefInfo(*callModRef)));
if (callModRef->getModSet().any())
modRefTable.AddDef(&callInst);
if (callModRef->getRefSet().any())
modRefTable.AddUse(&callInst);
}
// At a store instruction, add to the mod set the single node pointed to
// by the pointer argument of the store. Interestingly, if there is no
// such node, that would be a null pointer reference!
void visitStoreInst (StoreInst& storeInst) {
const DSNodeHandle& ptrNode =
funcGraph.getNodeForValue(storeInst.getPointerOperand());
if (const DSNode* target = ptrNode.getNode())
{
unsigned nodeId = funcModRef.getNodeId(target);
ModRefInfo& minfo =
modRefTable.modRefMap.insert(
std::make_pair(&storeInst,
ModRefInfo(funcGraph.getGraphSize()))).first->second;
minfo.setNodeIsMod(nodeId);
modRefTable.AddDef(&storeInst);
}
else
std::cerr << "Warning: Uninitialized pointer reference!\n";
}
// At a load instruction, add to the ref set the single node pointed to
// by the pointer argument of the load. Interestingly, if there is no
// such node, that would be a null pointer reference!
void visitLoadInst (LoadInst& loadInst) {
const DSNodeHandle& ptrNode =
funcGraph.getNodeForValue(loadInst.getPointerOperand());
if (const DSNode* target = ptrNode.getNode())
{
unsigned nodeId = funcModRef.getNodeId(target);
ModRefInfo& minfo =
modRefTable.modRefMap.insert(
std::make_pair(&loadInst,
ModRefInfo(funcGraph.getGraphSize()))).first->second;
minfo.setNodeIsRef(nodeId);
modRefTable.AddUse(&loadInst);
}
else
std::cerr << "Warning: Uninitialized pointer reference!\n";
}
};
//----------------------------------------------------------------------------
// class MemoryDepAnalysis: A dep. graph for load/store/call instructions
//----------------------------------------------------------------------------
/// Basic dependence gathering algorithm, using TarjanSCCIterator on CFG:
///
/// for every SCC S in the CFG in PostOrder on the SCC DAG
/// {
/// for every basic block BB in S in *postorder*
/// for every instruction I in BB in reverse
/// Add (I, ModRef[I]) to ModRefCurrent
/// if (Mod[I] != NULL)
/// Add I to DefSetCurrent: { I \in S : Mod[I] != NULL }
/// if (Ref[I] != NULL)
/// Add I to UseSetCurrent: { I : Ref[I] != NULL }
///
/// for every def D in DefSetCurrent
///
/// // NOTE: D comes after itself iff S contains a loop
/// if (HasLoop(S) && D & D)
/// Add output-dep: D -> D2
///
/// for every def D2 *after* D in DefSetCurrent
/// // NOTE: D2 comes before D in execution order
/// if (D & D2)
/// Add output-dep: D2 -> D
/// if (HasLoop(S))
/// Add output-dep: D -> D2
///
/// for every use U in UseSetCurrent that was seen *before* D
/// // NOTE: U comes after D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add true-dep: D -> U
/// if (HasLoop(S))
/// Add anti-dep: U -> D
///
/// for every use U in UseSetCurrent that was seen *after* D
/// // NOTE: U comes before D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add anti-dep: U -> D
/// if (HasLoop(S))
/// Add true-dep: D -> U
///
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after D in execution order
/// if (Dnext & D)
/// Add output-dep: D -> Dnext
///
/// for every use Unext in UseSetAfter
/// // NOTE: Unext comes after D in execution order
/// if (Unext & D)
/// Add true-dep: D -> Unext
///
/// for every use U in UseSetCurrent
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after U in execution order
/// if (Dnext & D)
/// Add anti-dep: U -> Dnext
///
/// Add ModRefCurrent to ModRefAfter: { (I, ModRef[I] ) }
/// Add DefSetCurrent to DefSetAfter: { I : Mod[I] != NULL }
/// Add UseSetCurrent to UseSetAfter: { I : Ref[I] != NULL }
/// }
///
///
void MemoryDepAnalysis::ProcessSCC(SCC<Function*>& S,
ModRefTable& ModRefAfter)
{
ModRefTable ModRefCurrent;
ModRefTable::ModRefMap& mapCurrent = ModRefCurrent.modRefMap;
ModRefTable::ModRefMap& mapAfter = ModRefAfter.modRefMap;
bool hasLoop = S.HasLoop();
// Builder class fills out a ModRefTable one instruction at a time.
// To use it, we just invoke it's visit function for each basic block:
//
// for each basic block BB in the SCC in *postorder*
// for each instruction I in BB in *reverse*
// ModRefInfoBuilder::visit(I)
// : Add (I, ModRef[I]) to ModRefCurrent.modRefMap
// : Add I to ModRefCurrent.definers if it defines any node
// : Add I to ModRefCurrent.users if it uses any node
//
ModRefInfoBuilder builder(*funcGraph, *funcModRef, ModRefCurrent);
for (SCC<Function*>::iterator BI=S.begin(), BE=S.end(); BI != BE; ++BI)
// Note: BBs in the SCC<> created by TarjanSCCIterator are in postorder.
for (BasicBlock::reverse_iterator II=(*BI)->rbegin(), IE=(*BI)->rend();
II != IE; ++II)
builder.visit(*II);
/// for every def D in DefSetCurrent
///
for (ModRefTable::ref_iterator II=ModRefCurrent.defsBegin(),
IE=ModRefCurrent.defsEnd(); II != IE; ++II)
{
/// // NOTE: D comes after itself iff S contains a loop
/// if (HasLoop(S))
/// Add output-dep: D -> D2
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **II, OutputDependence);
/// for every def D2 *after* D in DefSetCurrent
/// // NOTE: D2 comes before D in execution order
/// if (D2 & D)
/// Add output-dep: D2 -> D
/// if (HasLoop(S))
/// Add output-dep: D -> D2
for (ModRefTable::ref_iterator JI=II+1; JI != IE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getModSet()))
{
funcDepGraph->AddSimpleDependence(**JI, **II, OutputDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, OutputDependence);
}
/// for every use U in UseSetCurrent that was seen *before* D
/// // NOTE: U comes after D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add true-dep: U -> D
/// if (HasLoop(S))
/// Add anti-dep: D -> U
ModRefTable::ref_iterator JI=ModRefCurrent.usersBegin();
ModRefTable::ref_iterator JE = ModRefCurrent.usersBeforeDef_End(II);
for ( ; JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getRefSet()))
{
if (*II != *JI || hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**JI, **II, AntiDependence);
}
/// for every use U in UseSetCurrent that was seen *after* D
/// // NOTE: U comes before D in execution order
/// if (U & D)
/// if (U != D || HasLoop(S))
/// Add anti-dep: U -> D
/// if (HasLoop(S))
/// Add true-dep: D -> U
for (/*continue JI*/ JE = ModRefCurrent.usersEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapCurrent.find(*JI)->second.getRefSet()))
{
if (*II != *JI || hasLoop)
funcDepGraph->AddSimpleDependence(**JI, **II, AntiDependence);
if (hasLoop)
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
}
/// for every def Dnext in DefSetPrev
/// // NOTE: Dnext comes after D in execution order
/// if (Dnext & D)
/// Add output-dep: D -> Dnext
for (ModRefTable::ref_iterator JI=ModRefAfter.defsBegin(),
JE=ModRefAfter.defsEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapAfter.find(*JI)->second.getModSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, OutputDependence);
/// for every use Unext in UseSetAfter
/// // NOTE: Unext comes after D in execution order
/// if (Unext & D)
/// Add true-dep: D -> Unext
for (ModRefTable::ref_iterator JI=ModRefAfter.usersBegin(),
JE=ModRefAfter.usersEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getModSet(),
mapAfter.find(*JI)->second.getRefSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, TrueDependence);
}
///
/// for every use U in UseSetCurrent
/// for every def Dnext in DefSetAfter
/// // NOTE: Dnext comes after U in execution order
/// if (Dnext & D)
/// Add anti-dep: U -> Dnext
for (ModRefTable::ref_iterator II=ModRefCurrent.usersBegin(),
IE=ModRefCurrent.usersEnd(); II != IE; ++II)
for (ModRefTable::ref_iterator JI=ModRefAfter.defsBegin(),
JE=ModRefAfter.defsEnd(); JI != JE; ++JI)
if (!Disjoint(mapCurrent.find(*II)->second.getRefSet(),
mapAfter.find(*JI)->second.getModSet()))
funcDepGraph->AddSimpleDependence(**II, **JI, AntiDependence);
/// Add ModRefCurrent to ModRefAfter: { (I, ModRef[I] ) }
/// Add DefSetCurrent to DefSetAfter: { I : Mod[I] != NULL }
/// Add UseSetCurrent to UseSetAfter: { I : Ref[I] != NULL }
ModRefAfter.Insert(ModRefCurrent);
}
/// Debugging support methods
///
void MemoryDepAnalysis::print(std::ostream &O) const
{
// TEMPORARY LOOP
for (hash_map<Function*, DependenceGraph*>::const_iterator
I = funcMap.begin(), E = funcMap.end(); I != E; ++I)
{
Function* func = I->first;
DependenceGraph* depGraph = I->second;
O << "\n================================================================\n";
O << "DEPENDENCE GRAPH FOR MEMORY OPERATIONS IN FUNCTION " << func->getName();
O << "\n================================================================\n\n";
depGraph->print(*func, O);
}
}
///
/// Run the pass on a function
///
bool MemoryDepAnalysis::runOnFunction(Function& func)
{
assert(! func.isExternal());
// Get the FunctionModRefInfo holding IPModRef results for this function.
// Use the TD graph recorded within the FunctionModRefInfo object, which
// may not be the same as the original TD graph computed by DS analysis.
//
funcModRef = &getAnalysis<IPModRef>().getFunctionModRefInfo(func);
funcGraph = &funcModRef->getFuncGraph();
// TEMPORARY: ptr to depGraph (later just becomes "this").
assert(funcMap.find(&func) == funcMap.end() && "Analyzing function twice?");
funcDepGraph = funcMap[&func] = new DependenceGraph();
ModRefTable ModRefAfter;
SCC<Function*>* nextSCC;
for (TarjanSCC_iterator<Function*> tarjSCCiter = tarj_begin(&func);
(nextSCC = *tarjSCCiter) != NULL; ++tarjSCCiter)
ProcessSCC(*nextSCC, ModRefAfter);
return true;
}
//-------------------------------------------------------------------------
// TEMPORARY FUNCTIONS TO MAKE THIS A MODULE PASS ---
// These functions will go away once this class becomes a FunctionPass.
//
// Driver function to compute dependence graphs for every function.
// This is temporary and will go away once this is a FunctionPass.
//
bool MemoryDepAnalysis::run(Module& M)
{
for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
if (! FI->isExternal())
runOnFunction(*FI); // automatically inserts each depGraph into funcMap
return true;
}
// Release all the dependence graphs in the map.
void MemoryDepAnalysis::releaseMemory()
{
for (hash_map<Function*, DependenceGraph*>::const_iterator
I = funcMap.begin(), E = funcMap.end(); I != E; ++I)
delete I->second;
funcMap.clear();
// Clear pointers because the pass constructor will not be invoked again.
funcDepGraph = NULL;
funcGraph = NULL;
funcModRef = NULL;
}
MemoryDepAnalysis::~MemoryDepAnalysis()
{
releaseMemory();
}
//----END TEMPORARY FUNCTIONS----------------------------------------------
void MemoryDepAnalysis::dump() const
{
this->print(std::cerr);
}
static RegisterAnalysis<MemoryDepAnalysis>
Z("memdep", "Memory Dependence Analysis");