mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 04:30:12 +00:00
507bdf9488
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19506 91177308-0d34-0410-b5e6-96231b3b80d8
503 lines
20 KiB
C++
503 lines
20 KiB
C++
//===- MemoryDepAnalysis.cpp - Compute dep graph for memory ops -----------===//
|
|
//
|
|
// 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 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 "MemoryDepAnalysis.h"
|
|
#include "IPModRef.h"
|
|
#include "llvm/Instructions.h"
|
|
#include "llvm/Module.h"
|
|
#include "llvm/Analysis/DataStructure/DataStructure.h"
|
|
#include "llvm/Analysis/DataStructure/DSGraph.h"
|
|
#include "llvm/Support/InstVisitor.h"
|
|
#include "llvm/Support/CFG.h"
|
|
#include "llvm/ADT/SCCIterator.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/ADT/hash_map"
|
|
#include "llvm/ADT/hash_set"
|
|
|
|
namespace llvm {
|
|
|
|
///--------------------------------------------------------------------------
|
|
/// 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.
|
|
///--------------------------------------------------------------------------
|
|
|
|
class ModRefTable {
|
|
public:
|
|
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> {
|
|
const DSGraph& funcGraph;
|
|
const FunctionModRefInfo& funcModRef;
|
|
class ModRefTable& modRefTable;
|
|
|
|
ModRefInfoBuilder(); // DO NOT IMPLEMENT
|
|
ModRefInfoBuilder(const ModRefInfoBuilder&); // DO NOT IMPLEMENT
|
|
void operator=(const ModRefInfoBuilder&); // DO NOT IMPLEMENT
|
|
|
|
public:
|
|
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
|
|
//----------------------------------------------------------------------------
|
|
|
|
|
|
/// getAnalysisUsage - This does not modify anything. It uses the Top-Down DS
|
|
/// Graph and IPModRef.
|
|
///
|
|
void MemoryDepAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
AU.addRequired<TDDataStructures>();
|
|
AU.addRequired<IPModRef>();
|
|
}
|
|
|
|
|
|
/// Basic dependence gathering algorithm, using scc_iterator 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(std::vector<BasicBlock*> &S,
|
|
ModRefTable& ModRefAfter, bool hasLoop) {
|
|
ModRefTable ModRefCurrent;
|
|
ModRefTable::ModRefMap& mapCurrent = ModRefCurrent.modRefMap;
|
|
ModRefTable::ModRefMap& mapAfter = ModRefAfter.modRefMap;
|
|
|
|
// 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 (std::vector<BasicBlock*>::iterator BI = S.begin(), BE = S.end();
|
|
BI != BE; ++BI)
|
|
// Note: BBs in the SCC<> created by scc_iterator 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 Module*) 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 &F) {
|
|
assert(!F.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(F);
|
|
funcGraph = &funcModRef->getFuncGraph();
|
|
|
|
// TEMPORARY: ptr to depGraph (later just becomes "this").
|
|
assert(!funcMap.count(&F) && "Analyzing function twice?");
|
|
funcDepGraph = funcMap[&F] = new DependenceGraph();
|
|
|
|
ModRefTable ModRefAfter;
|
|
|
|
for (scc_iterator<Function*> I = scc_begin(&F), E = scc_end(&F); I != E; ++I)
|
|
ProcessSCC(*I, ModRefAfter, I.hasLoop());
|
|
|
|
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::runOnModule(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");
|
|
|
|
|
|
} // End llvm namespace
|