#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/PHITransAddr.h"
+#include "llvm/Analysis/OrderedBasicBlock.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
"Number of block queries that were completely cached");
// Limit for the number of instructions to scan in a block.
-static const unsigned int BlockScanLimit = 100;
+
+static cl::opt<unsigned> BlockScanLimit(
+ "memdep-block-scan-limit", cl::Hidden, cl::init(100),
+ cl::desc("The number of instructions to scan in a block in memory "
+ "dependency analysis (default = 100)"));
// Limit on the number of memdep results to process.
static const unsigned int NumResultsLimit = 100;
// Register this pass...
INITIALIZE_PASS_BEGIN(MemoryDependenceAnalysis, "memdep",
"Memory Dependence Analysis", false, true)
-INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(MemoryDependenceAnalysis, "memdep",
"Memory Dependence Analysis", false, true)
AU.setPreservesAll();
AU.addRequired<AssumptionCacheTracker>();
AU.addRequiredTransitive<AliasAnalysis>();
+ AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();
}
bool MemoryDependenceAnalysis::runOnFunction(Function &F) {
DominatorTreeWrapperPass *DTWP =
getAnalysisIfAvailable<DominatorTreeWrapperPass>();
DT = DTWP ? &DTWP->getDomTree() : nullptr;
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
return false;
}
/// location, fill in Loc with the details, otherwise set Loc.Ptr to null.
/// Return a ModRefInfo value describing the general behavior of the
/// instruction.
-static AliasAnalysis::ModRefResult
-GetLocation(const Instruction *Inst, MemoryLocation &Loc, AliasAnalysis *AA) {
+static ModRefInfo GetLocation(const Instruction *Inst, MemoryLocation &Loc,
+ const TargetLibraryInfo &TLI) {
if (const LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
if (LI->isUnordered()) {
Loc = MemoryLocation::get(LI);
- return AliasAnalysis::Ref;
+ return MRI_Ref;
}
if (LI->getOrdering() == Monotonic) {
Loc = MemoryLocation::get(LI);
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
}
Loc = MemoryLocation();
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
}
if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
if (SI->isUnordered()) {
Loc = MemoryLocation::get(SI);
- return AliasAnalysis::Mod;
+ return MRI_Mod;
}
if (SI->getOrdering() == Monotonic) {
Loc = MemoryLocation::get(SI);
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
}
Loc = MemoryLocation();
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
}
if (const VAArgInst *V = dyn_cast<VAArgInst>(Inst)) {
Loc = MemoryLocation::get(V);
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
}
- if (const CallInst *CI = isFreeCall(Inst, AA->getTargetLibraryInfo())) {
+ if (const CallInst *CI = isFreeCall(Inst, &TLI)) {
// calls to free() deallocate the entire structure
Loc = MemoryLocation(CI->getArgOperand(0));
- return AliasAnalysis::Mod;
+ return MRI_Mod;
}
if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
cast<ConstantInt>(II->getArgOperand(0))->getZExtValue(), AAInfo);
// These intrinsics don't really modify the memory, but returning Mod
// will allow them to be handled conservatively.
- return AliasAnalysis::Mod;
+ return MRI_Mod;
case Intrinsic::invariant_end:
II->getAAMetadata(AAInfo);
Loc = MemoryLocation(
cast<ConstantInt>(II->getArgOperand(1))->getZExtValue(), AAInfo);
// These intrinsics don't really modify the memory, but returning Mod
// will allow them to be handled conservatively.
- return AliasAnalysis::Mod;
+ return MRI_Mod;
default:
break;
}
// Otherwise, just do the coarse-grained thing that always works.
if (Inst->mayWriteToMemory())
- return AliasAnalysis::ModRef;
+ return MRI_ModRef;
if (Inst->mayReadFromMemory())
- return AliasAnalysis::Ref;
- return AliasAnalysis::NoModRef;
+ return MRI_Ref;
+ return MRI_NoModRef;
}
/// getCallSiteDependencyFrom - Private helper for finding the local
// If this inst is a memory op, get the pointer it accessed
MemoryLocation Loc;
- AliasAnalysis::ModRefResult MR = GetLocation(Inst, Loc, AA);
+ ModRefInfo MR = GetLocation(Inst, Loc, *TLI);
if (Loc.Ptr) {
// A simple instruction.
- if (AA->getModRefInfo(CS, Loc) != AliasAnalysis::NoModRef)
+ if (AA->getModRefInfo(CS, Loc) != MRI_NoModRef)
return MemDepResult::getClobber(Inst);
continue;
}
if (isa<DbgInfoIntrinsic>(Inst)) continue;
// If these two calls do not interfere, look past it.
switch (AA->getModRefInfo(CS, InstCS)) {
- case AliasAnalysis::NoModRef:
+ case MRI_NoModRef:
// If the two calls are the same, return InstCS as a Def, so that
// CS can be found redundant and eliminated.
- if (isReadOnlyCall && !(MR & AliasAnalysis::Mod) &&
+ if (isReadOnlyCall && !(MR & MRI_Mod) &&
CS.getInstruction()->isIdenticalToWhenDefined(Inst))
return MemDepResult::getDef(Inst);
// If we could not obtain a pointer for the instruction and the instruction
// touches memory then assume that this is a dependency.
- if (MR != AliasAnalysis::NoModRef)
+ if (MR != MRI_NoModRef)
return MemDepResult::getClobber(Inst);
}
const DataLayout &DL = BB->getModule()->getDataLayout();
+ // Create a numbered basic block to lazily compute and cache instruction
+ // positions inside a BB. This is used to provide fast queries for relative
+ // position between two instructions in a BB and can be used by
+ // AliasAnalysis::callCapturesBefore.
+ OrderedBasicBlock OBB(BB);
+
// Walk backwards through the basic block, looking for dependencies.
while (ScanIt != BB->begin()) {
Instruction *Inst = --ScanIt;
MemoryLocation LoadLoc = MemoryLocation::get(LI);
// If we found a pointer, check if it could be the same as our pointer.
- AliasAnalysis::AliasResult R = AA->alias(LoadLoc, MemLoc);
+ AliasResult R = AA->alias(LoadLoc, MemLoc);
if (isLoad) {
- if (R == AliasAnalysis::NoAlias) {
+ if (R == NoAlias) {
// If this is an over-aligned integer load (for example,
// "load i8* %P, align 4") see if it would obviously overlap with the
// queried location if widened to a larger load (e.g. if the queried
}
// Must aliased loads are defs of each other.
- if (R == AliasAnalysis::MustAlias)
+ if (R == MustAlias)
return MemDepResult::getDef(Inst);
#if 0 // FIXME: Temporarily disabled. GVN is cleverly rewriting loads
// If we have a partial alias, then return this as a clobber for the
// client to handle.
- if (R == AliasAnalysis::PartialAlias)
+ if (R == PartialAlias)
return MemDepResult::getClobber(Inst);
#endif
}
// Stores don't depend on other no-aliased accesses.
- if (R == AliasAnalysis::NoAlias)
+ if (R == NoAlias)
continue;
// Stores don't alias loads from read-only memory.
// If alias analysis can tell that this store is guaranteed to not modify
// the query pointer, ignore it. Use getModRefInfo to handle cases where
// the query pointer points to constant memory etc.
- if (AA->getModRefInfo(SI, MemLoc) == AliasAnalysis::NoModRef)
+ if (AA->getModRefInfo(SI, MemLoc) == MRI_NoModRef)
continue;
// Ok, this store might clobber the query pointer. Check to see if it is
MemoryLocation StoreLoc = MemoryLocation::get(SI);
// If we found a pointer, check if it could be the same as our pointer.
- AliasAnalysis::AliasResult R = AA->alias(StoreLoc, MemLoc);
+ AliasResult R = AA->alias(StoreLoc, MemLoc);
- if (R == AliasAnalysis::NoAlias)
+ if (R == NoAlias)
continue;
- if (R == AliasAnalysis::MustAlias)
+ if (R == MustAlias)
return MemDepResult::getDef(Inst);
if (isInvariantLoad)
continue;
// 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.
- const TargetLibraryInfo *TLI = AA->getTargetLibraryInfo();
if (isa<AllocaInst>(Inst) || isNoAliasFn(Inst, TLI)) {
const Value *AccessPtr = GetUnderlyingObject(MemLoc.Ptr, DL);
if (isInvariantLoad)
continue;
// Be conservative if the accessed pointer may alias the allocation.
- if (AA->alias(Inst, AccessPtr) != AliasAnalysis::NoAlias)
+ if (AA->alias(Inst, AccessPtr) != NoAlias)
return MemDepResult::getClobber(Inst);
// If the allocation is not aliased and does not read memory (like
// strdup), it is safe to ignore.
continue;
// See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
- AliasAnalysis::ModRefResult MR = AA->getModRefInfo(Inst, MemLoc);
+ ModRefInfo MR = AA->getModRefInfo(Inst, MemLoc);
// If necessary, perform additional analysis.
- if (MR == AliasAnalysis::ModRef)
- MR = AA->callCapturesBefore(Inst, MemLoc, DT);
+ if (MR == MRI_ModRef)
+ MR = AA->callCapturesBefore(Inst, MemLoc, DT, &OBB);
switch (MR) {
- case AliasAnalysis::NoModRef:
+ case MRI_NoModRef:
// If the call has no effect on the queried pointer, just ignore it.
continue;
- case AliasAnalysis::Mod:
+ case MRI_Mod:
return MemDepResult::getClobber(Inst);
- case AliasAnalysis::Ref:
+ case MRI_Ref:
// If the call is known to never store to the pointer, and if this is a
// load query, we can safely ignore it (scan past it).
if (isLoad)
LocalCache = MemDepResult::getNonFuncLocal();
} else {
MemoryLocation MemLoc;
- AliasAnalysis::ModRefResult MR = GetLocation(QueryInst, MemLoc, AA);
+ ModRefInfo MR = GetLocation(QueryInst, MemLoc, *TLI);
if (MemLoc.Ptr) {
// If we can do a pointer scan, make it happen.
- bool isLoad = !(MR & AliasAnalysis::Mod);
+ bool isLoad = !(MR & MRI_Mod);
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(QueryInst))
isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_start;
assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?");
- AA->deleteValue(RemInst);
DEBUG(verifyRemoved(RemInst));
}
/// verifyRemoved - Verify that the specified instruction does not occur
projects / oota-llvm.git / blobdiff