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Cache mapping information for a call site after computing it for a mod/ref 

query.  If the next mod/ref query happens to be for the same call site
(which is extremely likely), use the cache instead of recomputing the
callee/caller mapping.  This makes -aa-eval ***MUCH*** faster with
ds-aa

llvm-svn: 20871
This commit is contained in:
Chris Lattner 2005-03-26 23:29:03 +00:00
parent 139f43b340
commit 2ba37389c9
1 changed files with 81 additions and 27 deletions
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108
llvm/lib/Analysis/DataStructure/DataStructureAA.cpp
View File

@ -25,8 +25,25 @@ namespace {
class DSAA : public ModulePass, public AliasAnalysis {
TDDataStructures *TD;
BUDataStructures *BU;
// These members are used to cache mod/ref information to make us return
// results faster, particularly for aa-eval. On the first request of
// mod/ref information for a particular call site, we compute and store the
// calculated nodemap for the call site. Any time DSA info is updated we
// free this information, and when we move onto a new call site, this
// information is also freed.
CallSite MapCS;
std::multimap<DSNode*, const DSNode*> CallerCalleeMap;
public:
DSAA() : TD(0) {}
~DSAA() {
InvalidateCache();
}
void InvalidateCache() {
MapCS = CallSite();
CallerCalleeMap.clear();
}
//------------------------------------------------
// Implement the Pass API
@ -62,12 +79,14 @@ namespace {
}
virtual void deleteValue(Value *V) {
InvalidateCache();
BU->deleteValue(V);
TD->deleteValue(V);
}
virtual void copyValue(Value *From, Value *To) {
if (From == To) return;
InvalidateCache();
BU->copyValue(From, To);
TD->copyValue(From, To);
}
@ -149,11 +168,56 @@ AliasAnalysis::AliasResult DSAA::alias(const Value *V1, unsigned V1Size,
///
AliasAnalysis::ModRefResult
DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
AliasAnalysis::ModRefResult Result =AliasAnalysis::getModRefInfo(CS, P, Size);
DSNode *N = 0;
// First step, check our cache.
if (CS.getInstruction() == MapCS.getInstruction()) {
{
const Function *Caller = CS.getInstruction()->getParent()->getParent();
DSGraph &CallerTDGraph = TD->getDSGraph(*Caller);
// Figure out which node in the TD graph this pointer corresponds to.
DSScalarMap &CallerSM = CallerTDGraph.getScalarMap();
DSScalarMap::iterator NI = CallerSM.find(P);
if (NI == CallerSM.end()) {
InvalidateCache();
return DSAA::getModRefInfo(CS, P, Size);
}
N = NI->second.getNode();
}
HaveMappingInfo:
assert(N && "Null pointer in scalar map??");
typedef std::multimap<DSNode*, const DSNode*>::iterator NodeMapIt;
std::pair<NodeMapIt, NodeMapIt> Range = CallerCalleeMap.equal_range(N);
// Loop over all of the nodes in the callee that correspond to "N", keeping
// track of aggregate mod/ref info.
bool NeverReads = true, NeverWrites = true;
for (; Range.first != Range.second; ++Range.first) {
if (Range.first->second->isModified())
NeverWrites = false;
if (Range.first->second->isRead())
NeverReads = false;
if (NeverReads == false && NeverWrites == false)
return AliasAnalysis::getModRefInfo(CS, P, Size);
}
ModRefResult Result = ModRef;
if (NeverWrites) // We proved it was not modified.
Result = ModRefResult(Result & ~Mod);
if (NeverReads) // We proved it was not read.
Result = ModRefResult(Result & ~Ref);
return ModRefResult(Result & AliasAnalysis::getModRefInfo(CS, P, Size));
}
// Any cached info we have is for the wrong function.
InvalidateCache();
Function *F = CS.getCalledFunction();
if (!F || Result == NoModRef)
return Result;
if (!F) return AliasAnalysis::getModRefInfo(CS, P, Size);
if (F->isExternal()) {
// If we are calling an external function, and if this global doesn't escape
@ -169,14 +233,14 @@ DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
G = G->getGlobalsGraph();
NI = G->getScalarMap().find(P);
if (NI == G->getScalarMap().end())
return Result;
return AliasAnalysis::getModRefInfo(CS, P, Size);
}
// If we found a node and it's complete, it cannot be passed out to the
// called function.
if (NI->second.getNode()->isComplete())
return NoModRef;
return Result;
return AliasAnalysis::getModRefInfo(CS, P, Size);
}
// Get the graphs for the callee and caller. Note that we want the BU graph
@ -189,8 +253,9 @@ DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
DSScalarMap &CallerSM = CallerTDGraph.getScalarMap();
DSScalarMap::iterator NI = CallerSM.find(P);
if (NI == CallerSM.end()) {
ModRefResult Result = ModRef;
if (isa<ConstantPointerNull>(P) || isa<UndefValue>(P))
Result = NoModRef; // null is never modified :)
return NoModRef; // null is never modified :)
else {
assert(isa<GlobalVariable>(P) &&
cast<GlobalVariable>(P)->getType()->getElementType()->isFirstClassType() &&
@ -209,11 +274,10 @@ DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
Result = (ModRefResult)(Result & ~Ref);
}
}
return Result;
}
const DSNode *N = NI->second.getNode();
assert(N && "Null pointer in scalar map??");
if (Result == NoModRef) return Result;
return ModRefResult(Result & AliasAnalysis::getModRefInfo(CS, P, Size));
}
// Compute the mapping from nodes in the callee graph to the nodes in the
// caller graph for this call site.
@ -222,24 +286,14 @@ DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
CallerTDGraph.computeCalleeCallerMapping(DSCS, *F, CalleeBUGraph,
CalleeCallerMap);
// Loop over all of the nodes in the callee that correspond to "N", keeping
// track of aggregate mod/ref info.
bool NeverReads = true, NeverWrites = true;
// Remember the mapping and the call site for future queries.
MapCS = CS;
// Invert the mapping into CalleeCallerInvMap.
for (DSGraph::NodeMapTy::iterator I = CalleeCallerMap.begin(),
E = CalleeCallerMap.end(); I != E; ++I)
if (I->second.getNode() == N) {
if (I->first->isModified())
NeverWrites = false;
if (I->first->isRead())
NeverReads = false;
if (NeverReads == false && NeverWrites == false)
return Result;
}
CallerCalleeMap.insert(std::make_pair(I->second.getNode(), I->first));
if (NeverWrites) // We proved it was not modified.
Result = ModRefResult(Result & ~Mod);
if (NeverReads) // We proved it was not read.
Result = ModRefResult(Result & ~Ref);
return Result;
N = NI->second.getNode();
goto HaveMappingInfo;
}