#define DEBUG_TYPE "memdep"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
-#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Function.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/MallocHelper.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/PredIteratorCache.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetData.h"
using namespace llvm;
STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses");
void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<AliasAnalysis>();
- AU.addRequiredTransitive<TargetData>();
}
bool MemoryDependenceAnalysis::runOnFunction(Function &) {
AA = &getAnalysis<AliasAnalysis>();
- TD = &getAnalysis<TargetData>();
if (PredCache == 0)
PredCache.reset(new PredIteratorCache());
return false;
uint64_t PointerSize = 0;
if (StoreInst *S = dyn_cast<StoreInst>(Inst)) {
Pointer = S->getPointerOperand();
- PointerSize = TD->getTypeStoreSize(S->getOperand(0)->getType());
+ PointerSize = AA->getTypeStoreSize(S->getOperand(0)->getType());
} else if (VAArgInst *V = dyn_cast<VAArgInst>(Inst)) {
Pointer = V->getOperand(0);
- PointerSize = TD->getTypeStoreSize(V->getType());
+ PointerSize = AA->getTypeStoreSize(V->getType());
} else if (FreeInst *F = dyn_cast<FreeInst>(Inst)) {
Pointer = F->getPointerOperand();
// FreeInsts erase the entire structure
PointerSize = ~0ULL;
+ } else if (isFreeCall(Inst)) {
+ Pointer = Inst->getOperand(0);
+ // calls to free() erase the entire structure
+ PointerSize = ~0ULL;
} else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
// Debug intrinsics don't cause dependences.
if (isa<DbgInfoIntrinsic>(Inst)) continue;
// a load depends on another must aliased load from the same value.
if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
Value *Pointer = LI->getPointerOperand();
- uint64_t PointerSize = TD->getTypeStoreSize(LI->getType());
+ uint64_t PointerSize = AA->getTypeStoreSize(LI->getType());
// If we found a pointer, check if it could be the same as our pointer.
AliasAnalysis::AliasResult R =
// Ok, this store might clobber the query pointer. Check to see if it is
// a must alias: in this case, we want to return this as a def.
Value *Pointer = SI->getPointerOperand();
- uint64_t PointerSize = TD->getTypeStoreSize(SI->getOperand(0)->getType());
+ uint64_t PointerSize = AA->getTypeStoreSize(SI->getOperand(0)->getType());
// If we found a pointer, check if it could be the same as our pointer.
AliasAnalysis::AliasResult R =
// the allocation, return Def. This means that there is no dependence and
// the access can be optimized based on that. For example, a load could
// turn into undef.
- if (AllocationInst *AI = dyn_cast<AllocationInst>(Inst)) {
+ // Note: Only determine this to be a malloc if Inst is the malloc call, not
+ // a subsequent bitcast of the malloc call result. There can be stores to
+ // the malloced memory between the malloc call and its bitcast uses, and we
+ // need to continue scanning until the malloc call.
+ if (isa<AllocaInst>(Inst) || extractMallocCall(Inst)) {
Value *AccessPtr = MemPtr->getUnderlyingObject();
- if (AccessPtr == AI ||
- AA->alias(AI, 1, AccessPtr, 1) == AliasAnalysis::MustAlias)
- return MemDepResult::getDef(AI);
+ if (AccessPtr == Inst ||
+ AA->alias(Inst, 1, AccessPtr, 1) == AliasAnalysis::MustAlias)
+ return MemDepResult::getDef(Inst);
continue;
}
-
+
// See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
switch (AA->getModRefInfo(Inst, MemPtr, MemSize)) {
case AliasAnalysis::NoModRef:
LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
else {
MemPtr = SI->getPointerOperand();
- MemSize = TD->getTypeStoreSize(SI->getOperand(0)->getType());
+ MemSize = AA->getTypeStoreSize(SI->getOperand(0)->getType());
}
} else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) {
// If this is a volatile load, don't mess around with it. Just return the
LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
else {
MemPtr = LI->getPointerOperand();
- MemSize = TD->getTypeStoreSize(LI->getType());
+ MemSize = AA->getTypeStoreSize(LI->getType());
}
+ } else if (isFreeCall(QueryInst)) {
+ MemPtr = QueryInst->getOperand(0);
+ // calls to free() erase the entire structure, not just a field.
+ MemSize = ~0UL;
} else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
CallSite QueryCS = CallSite::get(QueryInst);
bool isReadOnly = AA->onlyReadsMemory(QueryCS);
// 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);
+ uint64_t PointeeSize = AA->getTypeStoreSize(EltTy);
// This is the set of blocks we've inspected, and the pointer we consider in
// each block. Because of critical edges, we currently bail out if querying
return Dep;
}
+/// SortNonLocalDepInfoCache - Sort the a NonLocalDepInfo cache, given a certain
+/// number of elements in the array that are already properly ordered. This is
+/// optimized for the case when only a few entries are added.
+static void
+SortNonLocalDepInfoCache(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
+ unsigned NumSortedEntries) {
+ switch (Cache.size() - NumSortedEntries) {
+ case 0:
+ // done, no new entries.
+ break;
+ case 2: {
+ // Two new entries, insert the last one into place.
+ MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back();
+ Cache.pop_back();
+ MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
+ std::upper_bound(Cache.begin(), Cache.end()-1, Val);
+ Cache.insert(Entry, Val);
+ // FALL THROUGH.
+ }
+ case 1:
+ // One new entry, Just insert the new value at the appropriate position.
+ if (Cache.size() != 1) {
+ MemoryDependenceAnalysis::NonLocalDepEntry Val = Cache.back();
+ Cache.pop_back();
+ MemoryDependenceAnalysis::NonLocalDepInfo::iterator Entry =
+ std::upper_bound(Cache.begin(), Cache.end(), Val);
+ Cache.insert(Entry, Val);
+ }
+ break;
+ default:
+ // Added many values, do a full scale sort.
+ std::sort(Cache.begin(), Cache.end());
+ break;
+ }
+}
+
/// getNonLocalPointerDepFromBB - Perform a dependency query based on
/// pointer/pointeesize starting at the end of StartBB. Add any clobber/def
// getNonLocalPointerDepFromBB and other routines that could reuse the cache
// value will only see properly sorted cache arrays.
if (Cache && NumSortedEntries != Cache->size()) {
- std::sort(Cache->begin(), Cache->end());
+ SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
NumSortedEntries = Cache->size();
}
}
// Okay, we're done now. If we added new values to the cache, re-sort it.
- switch (Cache->size()-NumSortedEntries) {
- case 0:
- // done, no new entries.
- break;
- case 2: {
- // Two new entries, insert the last one into place.
- NonLocalDepEntry Val = Cache->back();
- Cache->pop_back();
- NonLocalDepInfo::iterator Entry =
- std::upper_bound(Cache->begin(), Cache->end()-1, Val);
- Cache->insert(Entry, Val);
- // FALL THROUGH.
- }
- case 1:
- // One new entry, Just insert the new value at the appropriate position.
- if (Cache->size() != 1) {
- NonLocalDepEntry Val = Cache->back();
- Cache->pop_back();
- NonLocalDepInfo::iterator Entry =
- std::upper_bound(Cache->begin(), Cache->end(), Val);
- Cache->insert(Entry, Val);
- }
- break;
- default:
- // Added many values, do a full scale sort.
- std::sort(Cache->begin(), Cache->end());
- }
+ SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
DEBUG(AssertSorted(*Cache));
return false;
}
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