[llvm-commits] [llvm] r60654 - in /llvm/trunk: include/llvm/Analysis/MemoryDependenceAnalysis.h lib/Analysis/MemoryDependenceAnalysis.cpp
Chris Lattner
sabre at nondot.org
Sun Dec 7 00:50:21 PST 2008
Author: lattner
Date: Sun Dec 7 02:50:20 2008
New Revision: 60654
URL: http://llvm.org/viewvc/llvm-project?rev=60654&view=rev
Log:
add support for caching pointer dependence queries. Nothing uses this yet
so it "can't" break anything. That said, it does appear to work.
Modified:
llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h
llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
Modified: llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h?rev=60654&r1=60653&r2=60654&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h Sun Dec 7 02:50:20 2008
@@ -151,7 +151,25 @@
typedef std::pair<BasicBlock*, MemDepResult> NonLocalDepEntry;
typedef std::vector<NonLocalDepEntry> NonLocalDepInfo;
private:
-
+ /// ValueIsLoadPair - This is a pair<Value*, bool> where the bool is true if
+ /// the dependence is a read only dependence, false if read/write.
+ typedef PointerIntPair<Value*, 1, int> ValueIsLoadPair;
+
+ /// CachedNonLocalPointerInfo - This map stores the cached results of doing
+ /// a pointer lookup at the bottom of a block. Key key of this map is the
+ /// pointer+isload bit, the value is a list of <bb->result> mappings.
+ typedef DenseMap<ValueIsLoadPair, NonLocalDepInfo>CachedNonLocalPointerInfo;
+ CachedNonLocalPointerInfo NonLocalPointerDeps;
+
+ // A map from instructions to their non-local pointer dependencies.
+ // The elements of the SmallPtrSet are ValueIsLoadPair's.
+ typedef DenseMap<Instruction*,
+ SmallPtrSet<void*, 4> > ReverseNonLocalPtrDepTy;
+ ReverseNonLocalPtrDepTy ReverseNonLocalPtrDeps;
+
+
+
+
/// PerInstNLInfo - This is the instruction we keep for each cached access
/// that we have for an instruction. The pointer is an owning pointer and
/// the bool indicates whether we have any dirty bits in the set.
@@ -185,9 +203,10 @@
void releaseMemory() {
LocalDeps.clear();
NonLocalDeps.clear();
- NonLocalDeps.clear();
+ NonLocalPointerDeps.clear();
ReverseLocalDeps.clear();
ReverseNonLocalDeps.clear();
+ ReverseNonLocalPtrDeps.clear();
}
/// getAnalysisUsage - Does not modify anything. It uses Value Numbering
@@ -229,10 +248,6 @@
void removeInstruction(Instruction *InstToRemove);
private:
-
- /// getDependencyFrom - Return the instruction on which the memory location
- /// '*Pointer' depends. This starts scanning from the instruction before
- /// the position indicated by ScanIt.
MemDepResult getPointerDependencyFrom(Value *Pointer, uint64_t MemSize,
bool isLoad,
BasicBlock::iterator ScanIt,
@@ -240,12 +255,11 @@
MemDepResult getCallSiteDependencyFrom(CallSite C,
BasicBlock::iterator ScanIt,
BasicBlock *BB);
-
void getNonLocalPointerDepInternal(Value *Pointer, uint64_t Size,
bool isLoad, BasicBlock *BB,
SmallVectorImpl<NonLocalDepEntry> &Result,
SmallPtrSet<BasicBlock*, 64> &Visited);
-
+ void RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P);
/// verifyRemoved - Verify that the specified instruction does not occur
/// in our internal data structures.
Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=60654&r1=60653&r2=60654&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Sun Dec 7 02:50:20 2008
@@ -21,9 +21,7 @@
#include "llvm/Function.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/CFG.h"
-#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
@@ -31,6 +29,14 @@
STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses");
STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses");
STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses");
+
+STATISTIC(NumCacheNonLocalPtr,
+ "Number of fully cached non-local ptr responses");
+STATISTIC(NumCacheDirtyNonLocalPtr,
+ "Number of cached, but dirty, non-local ptr responses");
+STATISTIC(NumUncacheNonLocalPtr,
+ "Number of uncached non-local ptr responses");
+
char MemoryDependenceAnalysis::ID = 0;
// Register this pass...
@@ -74,7 +80,7 @@
Pointer = F->getPointerOperand();
// FreeInsts erase the entire structure
- PointerSize = ~0UL;
+ PointerSize = ~0ULL;
} else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
CallSite InstCS = CallSite::get(Inst);
// If these two calls do not interfere, look past it.
@@ -115,7 +121,7 @@
getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad,
BasicBlock::iterator ScanIt, BasicBlock *BB) {
- // Walk backwards through the basic block, looking for dependencies
+ // Walk backwards through the basic block, looking for dependencies.
while (ScanIt != BB->begin()) {
Instruction *Inst = --ScanIt;
@@ -134,6 +140,8 @@
// May-alias loads don't depend on each other without a dependence.
if (isLoad && R == AliasAnalysis::MayAlias)
continue;
+ // Stores depend on may and must aliased loads, loads depend on must-alias
+ // loads.
return MemDepResult::getDef(Inst);
}
@@ -200,8 +208,10 @@
ScanPos = Inst;
SmallPtrSet<Instruction*, 4> &InstMap = ReverseLocalDeps[Inst];
- InstMap.erase(QueryInst);
+ bool Found = InstMap.erase(QueryInst);
+ assert(Found && "Invalid reverse map!"); Found=Found;
if (InstMap.empty())
+ // FIXME: use an iterator to avoid looking up inst again.
ReverseLocalDeps.erase(Inst);
}
@@ -356,7 +366,9 @@
// We're removing QueryInst's use of Inst.
SmallPtrSet<Instruction*, 4> &InstMap = ReverseNonLocalDeps[Inst];
- InstMap.erase(QueryInst);
+ bool Found = InstMap.erase(QueryInst);
+ assert(Found && "Invalid reverse map!"); Found=Found;
+ // FIXME: Use an iterator to avoid looking up inst again.
if (InstMap.empty()) ReverseNonLocalDeps.erase(Inst);
}
}
@@ -441,7 +453,6 @@
// We know that the pointer value is live into FromBB find the def/clobbers
// from presecessors.
-
const Type *EltTy = cast<PointerType>(Pointer->getType())->getElementType();
uint64_t PointeeSize = TD->getTypeStoreSize(EltTy);
@@ -464,6 +475,17 @@
SmallVector<BasicBlock*, 32> Worklist;
Worklist.push_back(StartBB);
+ // Look up the cached info for Pointer.
+ ValueIsLoadPair CacheKey(Pointer, isLoad);
+ NonLocalDepInfo *Cache = &NonLocalPointerDeps[CacheKey];
+
+ // Keep track of the entries that we know are sorted. Previously cached
+ // entries will all be sorted. The entries we add we only sort on demand (we
+ // don't insert every element into its sorted position). We know that we
+ // won't get any reuse from currently inserted values, because we don't
+ // revisit blocks after we insert info for them.
+ unsigned NumSortedEntries = Cache->size();
+
while (!Worklist.empty()) {
BasicBlock *BB = Worklist.pop_back_val();
@@ -471,11 +493,70 @@
// been here.
if (!Visited.insert(BB))
continue;
+
+ // Get the dependency info for Pointer in BB. If we have cached
+ // information, we will use it, otherwise we compute it.
- // FIXME: CACHE!
+ // Do a binary search to see if we already have an entry for this block in
+ // the cache set. If so, find it.
+ NonLocalDepInfo::iterator Entry =
+ std::upper_bound(Cache->begin(), Cache->begin()+NumSortedEntries,
+ std::make_pair(BB, MemDepResult()));
+ if (Entry != Cache->begin() && (&*Entry)[-1].first == BB)
+ --Entry;
- MemDepResult Dep =
- getPointerDependencyFrom(Pointer, PointeeSize, isLoad, BB->end(), BB);
+ MemDepResult *ExistingResult = 0;
+ if (Entry != Cache->begin()+NumSortedEntries && Entry->first == BB)
+ ExistingResult = &Entry->second;
+
+ // If we have a cached entry, and it is non-dirty, use it as the value for
+ // this dependency.
+ MemDepResult Dep;
+ if (ExistingResult && !ExistingResult->isDirty()) {
+ Dep = *ExistingResult;
+ ++NumCacheNonLocalPtr;
+ } else {
+ // Otherwise, we have to scan for the value. If we have a dirty cache
+ // entry, start scanning from its position, otherwise we scan from the end
+ // of the block.
+ BasicBlock::iterator ScanPos = BB->end();
+ if (ExistingResult && ExistingResult->getInst()) {
+ assert(ExistingResult->getInst()->getParent() == BB &&
+ "Instruction invalidated?");
+ ++NumCacheDirtyNonLocalPtr;
+ ScanPos = ExistingResult->getInst();
+
+ // Eliminating the dirty entry from 'Cache', so update the reverse info.
+ SmallPtrSet<void *, 4> &InstMap = ReverseNonLocalPtrDeps[ScanPos];
+ bool Contained = InstMap.erase(CacheKey.getOpaqueValue());
+ assert(Contained && "Invalid cache entry"); Contained=Contained;
+ // FIXME: Use an iterator to avoid a repeated lookup in ".erase".
+ if (InstMap.empty()) ReverseNonLocalPtrDeps.erase(ScanPos);
+ } else {
+ ++NumUncacheNonLocalPtr;
+ }
+
+ // Scan the block for the dependency.
+ Dep = getPointerDependencyFrom(Pointer, PointeeSize, isLoad, ScanPos, BB);
+
+ // If we had a dirty entry for the block, update it. Otherwise, just add
+ // a new entry.
+ if (ExistingResult)
+ *ExistingResult = Dep;
+ else
+ Cache->push_back(std::make_pair(BB, Dep));
+
+ // If the block has a dependency (i.e. it isn't completely transparent to
+ // the value), remember the reverse association because we just added it
+ // to Cache!
+ if (!Dep.isNonLocal()) {
+ // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently
+ // update MemDep when we remove instructions.
+ Instruction *Inst = Dep.getInst();
+ assert(Inst && "Didn't depend on anything?");
+ ReverseNonLocalPtrDeps[Inst].insert(CacheKey.getOpaqueValue());
+ }
+ }
// If we got a Def or Clobber, add this to the list of results.
if (!Dep.isNonLocal()) {
@@ -490,6 +571,40 @@
Worklist.push_back(*PI);
}
}
+
+ // If we computed new values, re-sort Cache.
+ if (NumSortedEntries != Cache->size())
+ std::sort(Cache->begin(), Cache->end());
+}
+
+/// RemoveCachedNonLocalPointerDependencies - If P exists in
+/// CachedNonLocalPointerInfo, remove it.
+void MemoryDependenceAnalysis::
+RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) {
+ CachedNonLocalPointerInfo::iterator It =
+ NonLocalPointerDeps.find(P);
+ if (It == NonLocalPointerDeps.end()) return;
+
+ // Remove all of the entries in the BB->val map. This involves removing
+ // instructions from the reverse map.
+ NonLocalDepInfo &PInfo = It->second;
+
+ for (unsigned i = 0, e = PInfo.size(); i != e; ++i) {
+ Instruction *Target = PInfo[i].second.getInst();
+ if (Target == 0) continue; // Ignore non-local dep results.
+ assert(Target->getParent() == PInfo[i].first && Target != P.getPointer());
+
+ // Eliminating the dirty entry from 'Cache', so update the reverse info.
+ SmallPtrSet<void *, 4> &InstMap = ReverseNonLocalPtrDeps[Target];
+ bool Contained = InstMap.erase(P.getOpaqueValue());
+ assert(Contained && "Invalid cache entry"); Contained=Contained;
+
+ // FIXME: Use an iterator to avoid a repeated lookup in ".erase".
+ if (InstMap.empty()) ReverseNonLocalPtrDeps.erase(Target);
+ }
+
+ // Remove P from NonLocalPointerDeps (which deletes NonLocalDepInfo).
+ NonLocalPointerDeps.erase(It);
}
@@ -516,14 +631,27 @@
// Remove us from DepInst's reverse set now that the local dep info is gone.
if (Instruction *Inst = LocalDepEntry->second.getInst()) {
SmallPtrSet<Instruction*, 4> &RLD = ReverseLocalDeps[Inst];
- RLD.erase(RemInst);
+ bool Found = RLD.erase(RemInst);
+ assert(Found && "Invalid reverse map!"); Found=Found;
+ // FIXME: Use an iterator to avoid looking up Inst again.
if (RLD.empty())
ReverseLocalDeps.erase(Inst);
}
// Remove this local dependency info.
LocalDeps.erase(LocalDepEntry);
- }
+ }
+
+ // If we have any cached pointer dependencies on this instruction, remove
+ // them. If the instruction has non-pointer type, then it can't be a pointer
+ // base.
+
+ // Remove it from both the load info and the store info. The instruction
+ // can't be in either of these maps if it is non-pointer.
+ if (isa<PointerType>(RemInst->getType())) {
+ RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, false));
+ RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(RemInst, true));
+ }
// Loop over all of the things that depend on the instruction we're removing.
//
@@ -532,7 +660,7 @@
ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst);
if (ReverseDepIt != ReverseLocalDeps.end()) {
SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second;
- // RemInst can't be the terminator if it has stuff depending on it.
+ // RemInst can't be the terminator if it has local stuff depending on it.
assert(!ReverseDeps.empty() && !isa<TerminatorInst>(RemInst) &&
"Nothing can locally depend on a terminator");
@@ -540,7 +668,7 @@
// dependent on the instruction after RemInst. It will have the dirty flag
// set so it will rescan. This saves having to scan the entire block to get
// to this point.
- Instruction *NewDepInst = next(BasicBlock::iterator(RemInst));
+ Instruction *NewDepInst = ++BasicBlock::iterator(RemInst);
for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(),
E = ReverseDeps.end(); I != E; ++I) {
@@ -568,8 +696,8 @@
ReverseDepIt = ReverseNonLocalDeps.find(RemInst);
if (ReverseDepIt != ReverseNonLocalDeps.end()) {
- SmallPtrSet<Instruction*, 4>& set = ReverseDepIt->second;
- for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end();
+ SmallPtrSet<Instruction*, 4> &Set = ReverseDepIt->second;
+ for (SmallPtrSet<Instruction*, 4>::iterator I = Set.begin(), E = Set.end();
I != E; ++I) {
assert(*I != RemInst && "Already removed NonLocalDep info for RemInst");
@@ -584,7 +712,7 @@
// Convert to a dirty entry for the subsequent instruction.
Instruction *NextI = 0;
if (!RemInst->isTerminator()) {
- NextI = next(BasicBlock::iterator(RemInst));
+ NextI = ++BasicBlock::iterator(RemInst);
ReverseDepsToAdd.push_back(std::make_pair(NextI, *I));
}
DI->second = MemDepResult::getDirty(NextI);
@@ -601,6 +729,50 @@
}
}
+ // If the instruction is in ReverseNonLocalPtrDeps then it appears as a
+ // value in the NonLocalPointerDeps info.
+ ReverseNonLocalPtrDepTy::iterator ReversePtrDepIt =
+ ReverseNonLocalPtrDeps.find(RemInst);
+ if (ReversePtrDepIt != ReverseNonLocalPtrDeps.end()) {
+ SmallPtrSet<void*, 4> &Set = ReversePtrDepIt->second;
+ SmallVector<std::pair<Instruction*, ValueIsLoadPair>,8> ReversePtrDepsToAdd;
+
+ for (SmallPtrSet<void*, 4>::iterator I = Set.begin(), E = Set.end();
+ I != E; ++I) {
+ ValueIsLoadPair P;
+ P.setFromOpaqueValue(*I);
+ assert(P.getPointer() != RemInst &&
+ "Already removed NonLocalPointerDeps info for RemInst");
+
+ NonLocalDepInfo &NLPDI = NonLocalPointerDeps[P];
+
+ MemDepResult NewDirtyVal;
+ if (!RemInst->isTerminator())
+ NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst));
+
+ // Update any entries for RemInst to use the instruction after it.
+ for (NonLocalDepInfo::iterator DI = NLPDI.begin(), DE = NLPDI.end();
+ DI != DE; ++DI) {
+ if (DI->second.getInst() != RemInst) continue;
+
+ // Convert to a dirty entry for the subsequent instruction.
+ DI->second = NewDirtyVal;
+
+ if (Instruction *NewDirtyInst = NewDirtyVal.getInst())
+ ReversePtrDepsToAdd.push_back(std::make_pair(NewDirtyInst, P));
+ }
+ }
+
+ ReverseNonLocalPtrDeps.erase(ReversePtrDepIt);
+
+ while (!ReversePtrDepsToAdd.empty()) {
+ ReverseNonLocalPtrDeps[ReversePtrDepsToAdd.back().first]
+ .insert(ReversePtrDepsToAdd.back().second.getOpaqueValue());
+ ReversePtrDepsToAdd.pop_back();
+ }
+ }
+
+
assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?");
AA->deleteValue(RemInst);
DEBUG(verifyRemoved(RemInst));
@@ -616,6 +788,15 @@
"Inst occurs in data structures");
}
+ for (CachedNonLocalPointerInfo::const_iterator I =NonLocalPointerDeps.begin(),
+ E = NonLocalPointerDeps.end(); I != E; ++I) {
+ assert(I->first.getPointer() != D && "Inst occurs in NLPD map key");
+ const NonLocalDepInfo &Val = I->second;
+ for (NonLocalDepInfo::const_iterator II = Val.begin(), E = Val.end();
+ II != E; ++II)
+ assert(II->second.getInst() != D && "Inst occurs as NLPD value");
+ }
+
for (NonLocalDepMapType::const_iterator I = NonLocalDeps.begin(),
E = NonLocalDeps.end(); I != E; ++I) {
assert(I->first != D && "Inst occurs in data structures");
@@ -641,4 +822,17 @@
EE = I->second.end(); II != EE; ++II)
assert(*II != D && "Inst occurs in data structures");
}
+
+ for (ReverseNonLocalPtrDepTy::const_iterator
+ I = ReverseNonLocalPtrDeps.begin(),
+ E = ReverseNonLocalPtrDeps.end(); I != E; ++I) {
+ assert(I->first != D && "Inst occurs in rev NLPD map");
+
+ for (SmallPtrSet<void*, 4>::const_iterator II = I->second.begin(),
+ E = I->second.end(); II != E; ++II)
+ assert(*II != ValueIsLoadPair(D, false).getOpaqueValue() &&
+ *II != ValueIsLoadPair(D, true).getOpaqueValue() &&
+ "Inst occurs in ReverseNonLocalPtrDeps map");
+ }
+
}
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