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authorVikram S. Adve <vadve@cs.uiuc.edu>2002-12-08 13:26:29 +0000
committerVikram S. Adve <vadve@cs.uiuc.edu>2002-12-08 13:26:29 +0000
commit96b21c1054832f6e11a1a91e4df95d65016c9039 (patch)
treee40d1a6eb8846b3a59cec77d7a52ea307c9bd509 /include
parent138b0cd7daae5f95e1f851bd885cc0b385732abf (diff)
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An explicit representation of dependence graphs, and a pass that
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
Diffstat (limited to 'include')
-rw-r--r--include/llvm/Analysis/DependenceGraph.h250
-rw-r--r--include/llvm/Analysis/MemoryDepAnalysis.h115
2 files changed, 365 insertions, 0 deletions
diff --git a/include/llvm/Analysis/DependenceGraph.h b/include/llvm/Analysis/DependenceGraph.h
new file mode 100644
index 0000000..9c803f0
--- /dev/null
+++ b/include/llvm/Analysis/DependenceGraph.h
@@ -0,0 +1,250 @@
+//===- 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
diff --git a/include/llvm/Analysis/MemoryDepAnalysis.h b/include/llvm/Analysis/MemoryDepAnalysis.h
new file mode 100644
index 0000000..965a2f4
--- /dev/null
+++ b/include/llvm/Analysis/MemoryDepAnalysis.h
@@ -0,0 +1,115 @@
+//===- 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