#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
#include <map>
#include <stack>
using namespace llvm;
INITIALIZE_PASS_BEGIN(LazyValueInfo, "lazy-value-info",
"Lazy Value Information Analysis", false, true)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info",
"Lazy Value Information Analysis", false, true)
// LVILatticeVal
//===----------------------------------------------------------------------===//
-/// LVILatticeVal - This is the information tracked by LazyValueInfo for each
-/// value.
+/// This is the information tracked by LazyValueInfo for each value.
///
/// FIXME: This is basically just for bringup, this can be made a lot more rich
/// in the future.
namespace {
class LVILatticeVal {
enum LatticeValueTy {
- /// undefined - This Value has no known value yet.
+ /// This Value has no known value yet.
undefined,
- /// constant - This Value has a specific constant value.
+ /// This Value has a specific constant value.
constant,
- /// notconstant - This Value is known to not have the specified value.
+
+ /// This Value is known to not have the specified value.
notconstant,
- /// constantrange - The Value falls within this range.
+ /// The Value falls within this range.
constantrange,
- /// overdefined - This value is not known to be constant, and we know that
- /// it has a value.
+ /// This value is not known to be constant, and we know that it has a value.
overdefined
};
return Range;
}
- /// markOverdefined - Return true if this is a change in status.
+ /// Return true if this is a change in status.
bool markOverdefined() {
if (isOverdefined())
return false;
return true;
}
- /// markConstant - Return true if this is a change in status.
+ /// Return true if this is a change in status.
bool markConstant(Constant *V) {
assert(V && "Marking constant with NULL");
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return true;
}
- /// markNotConstant - Return true if this is a change in status.
+ /// Return true if this is a change in status.
bool markNotConstant(Constant *V) {
assert(V && "Marking constant with NULL");
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return true;
}
- /// markConstantRange - Return true if this is a change in status.
+ /// Return true if this is a change in status.
bool markConstantRange(const ConstantRange NewR) {
if (isConstantRange()) {
if (NewR.isEmptySet())
return true;
}
- /// mergeIn - Merge the specified lattice value into this one, updating this
+ /// Merge the specified lattice value into this one, updating this
/// one and returning true if anything changed.
- bool mergeIn(const LVILatticeVal &RHS) {
+ bool mergeIn(const LVILatticeVal &RHS, const DataLayout &DL) {
if (RHS.isUndefined() || isOverdefined()) return false;
if (RHS.isOverdefined()) return markOverdefined();
// Unless we can prove that the two Constants are different, we must
// move to overdefined.
- // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding.
- if (ConstantInt *Res = dyn_cast<ConstantInt>(
- ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
- getConstant(),
- RHS.getNotConstant())))
+ if (ConstantInt *Res =
+ dyn_cast<ConstantInt>(ConstantFoldCompareInstOperands(
+ CmpInst::ICMP_NE, getConstant(), RHS.getNotConstant(), DL)))
if (Res->isOne())
return markNotConstant(RHS.getNotConstant());
// Unless we can prove that the two Constants are different, we must
// move to overdefined.
- // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding.
- if (ConstantInt *Res = dyn_cast<ConstantInt>(
- ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
- getNotConstant(),
- RHS.getConstant())))
+ if (ConstantInt *Res =
+ dyn_cast<ConstantInt>(ConstantFoldCompareInstOperands(
+ CmpInst::ICMP_NE, getNotConstant(), RHS.getConstant(), DL)))
if (Res->isOne())
return false;
//===----------------------------------------------------------------------===//
namespace {
- /// LVIValueHandle - A callback value handle updates the cache when
- /// values are erased.
+ /// A callback value handle updates the cache when values are erased.
class LazyValueInfoCache;
struct LVIValueHandle : public CallbackVH {
LazyValueInfoCache *Parent;
}
namespace {
- /// LazyValueInfoCache - This is the cache kept by LazyValueInfo which
+ /// This is the cache kept by LazyValueInfo which
/// maintains information about queries across the clients' queries.
class LazyValueInfoCache {
- /// ValueCacheEntryTy - This is all of the cached block information for
- /// exactly one Value*. The entries are sorted by the BasicBlock* of the
+ /// This is all of the cached block information for exactly one Value*.
+ /// The entries are sorted by the BasicBlock* of the
/// entries, allowing us to do a lookup with a binary search.
typedef std::map<AssertingVH<BasicBlock>, LVILatticeVal> ValueCacheEntryTy;
- /// ValueCache - This is all of the cached information for all values,
+ /// This is all of the cached information for all values,
/// mapped from Value* to key information.
std::map<LVIValueHandle, ValueCacheEntryTy> ValueCache;
- /// OverDefinedCache - This tracks, on a per-block basis, the set of
- /// values that are over-defined at the end of that block. This is required
+ /// This tracks, on a per-block basis, the set of values that are
+ /// over-defined at the end of that block. This is required
/// for cache updating.
typedef std::pair<AssertingVH<BasicBlock>, Value*> OverDefinedPairTy;
DenseSet<OverDefinedPairTy> OverDefinedCache;
- /// SeenBlocks - Keep track of all blocks that we have ever seen, so we
+ /// Keep track of all blocks that we have ever seen, so we
/// don't spend time removing unused blocks from our caches.
DenseSet<AssertingVH<BasicBlock> > SeenBlocks;
- /// BlockValueStack - This stack holds the state of the value solver
- /// during a query. It basically emulates the callstack of the naive
+ /// This stack holds the state of the value solver during a query.
+ /// It basically emulates the callstack of the naive
/// recursive value lookup process.
std::stack<std::pair<BasicBlock*, Value*> > BlockValueStack;
- /// BlockValueSet - Keeps track of which block-value pairs are in
- /// BlockValueStack.
+ /// Keeps track of which block-value pairs are in BlockValueStack.
DenseSet<std::pair<BasicBlock*, Value*> > BlockValueSet;
- /// pushBlockValue - Push BV onto BlockValueStack unless it's already in
- /// there. Returns true on success.
+ /// Push BV onto BlockValueStack unless it's already in there.
+ /// Returns true on success.
bool pushBlockValue(const std::pair<BasicBlock *, Value *> &BV) {
- if (BlockValueSet.count(BV))
+ if (!BlockValueSet.insert(BV).second)
return false; // It's already in the stack.
BlockValueStack.push(BV);
- BlockValueSet.insert(BV);
return true;
}
- /// A pointer to the cache of @llvm.assume calls.
- AssumptionCache *AC;
- /// An optional DL pointer.
- const DataLayout *DL;
- /// An optional DT pointer.
- DominatorTree *DT;
-
+ AssumptionCache *AC; ///< A pointer to the cache of @llvm.assume calls.
+ const DataLayout &DL; ///< A mandatory DataLayout
+ DominatorTree *DT; ///< An optional DT pointer.
+
friend struct LVIValueHandle;
void insertResult(Value *Val, BasicBlock *BB, const LVILatticeVal &Result) {
}
public:
- /// getValueInBlock - This is the query interface to determine the lattice
+ /// This is the query interface to determine the lattice
/// value for the specified Value* at the end of the specified block.
LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB,
Instruction *CxtI = nullptr);
- /// getValueAt - This is the query interface to determine the lattice
+ /// This is the query interface to determine the lattice
/// value for the specified Value* at the specified instruction (generally
/// from an assume intrinsic).
LVILatticeVal getValueAt(Value *V, Instruction *CxtI);
- /// getValueOnEdge - This is the query interface to determine the lattice
+ /// This is the query interface to determine the lattice
/// value for the specified Value* that is true on the specified edge.
LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB,
Instruction *CxtI = nullptr);
- /// threadEdge - This is the update interface to inform the cache that an
- /// edge from PredBB to OldSucc has been threaded to be from PredBB to
- /// NewSucc.
+ /// This is the update interface to inform the cache that an edge from
+ /// PredBB to OldSucc has been threaded to be from PredBB to NewSucc.
void threadEdge(BasicBlock *PredBB,BasicBlock *OldSucc,BasicBlock *NewSucc);
- /// eraseBlock - This is part of the update interface to inform the cache
+ /// This is part of the update interface to inform the cache
/// that a block has been deleted.
void eraseBlock(BasicBlock *BB);
OverDefinedCache.clear();
}
- LazyValueInfoCache(AssumptionCache *AC, const DataLayout *DL = nullptr,
+ LazyValueInfoCache(AssumptionCache *AC, const DataLayout &DL,
DominatorTree *DT = nullptr)
: AC(AC), DL(DL), DT(DT) {}
};
static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) {
if (LoadInst *L = dyn_cast<LoadInst>(I)) {
return L->getPointerAddressSpace() == 0 &&
- GetUnderlyingObject(L->getPointerOperand()) == Ptr;
+ GetUnderlyingObject(L->getPointerOperand(),
+ L->getModule()->getDataLayout()) == Ptr;
}
if (StoreInst *S = dyn_cast<StoreInst>(I)) {
return S->getPointerAddressSpace() == 0 &&
- GetUnderlyingObject(S->getPointerOperand()) == Ptr;
+ GetUnderlyingObject(S->getPointerOperand(),
+ S->getModule()->getDataLayout()) == Ptr;
}
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) {
if (MI->isVolatile()) return false;
if (!Len || Len->isZero()) return false;
if (MI->getDestAddressSpace() == 0)
- if (GetUnderlyingObject(MI->getRawDest()) == Ptr)
+ if (GetUnderlyingObject(MI->getRawDest(),
+ MI->getModule()->getDataLayout()) == Ptr)
return true;
if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI))
if (MTI->getSourceAddressSpace() == 0)
- if (GetUnderlyingObject(MTI->getRawSource()) == Ptr)
+ if (GetUnderlyingObject(MTI->getRawSource(),
+ MTI->getModule()->getDataLayout()) == Ptr)
return true;
}
return false;
if (isKnownNonNull(Val)) {
NotNull = true;
} else {
- Value *UnderlyingVal = GetUnderlyingObject(Val);
+ const DataLayout &DL = BB->getModule()->getDataLayout();
+ Value *UnderlyingVal = GetUnderlyingObject(Val, DL);
// If 'GetUnderlyingObject' didn't converge, skip it. It won't converge
// inside InstructionDereferencesPointer either.
- if (UnderlyingVal == GetUnderlyingObject(UnderlyingVal, nullptr, 1)) {
+ if (UnderlyingVal == GetUnderlyingObject(UnderlyingVal, DL, 1)) {
for (Instruction &I : *BB) {
if (InstructionDereferencesPointer(&I, UnderlyingVal)) {
NotNull = true;
if (EdgesMissing)
continue;
- Result.mergeIn(EdgeResult);
+ Result.mergeIn(EdgeResult, DL);
// If we hit overdefined, exit early. The BlockVals entry is already set
// to overdefined.
if (EdgesMissing)
continue;
- Result.mergeIn(EdgeResult);
+ Result.mergeIn(EdgeResult, DL);
// If we hit overdefined, exit early. The BlockVals entry is already set
// to overdefined.
if (!AssumeVH)
continue;
auto *I = cast<CallInst>(AssumeVH);
- if (!isValidAssumeForContext(I, BBI, DL, DT))
+ if (!isValidAssumeForContext(I, BBI, DT))
continue;
Value *C = I->getArgOperand(0);
if (BBLV.isOverdefined())
BBLV = Result;
else
- BBLV.mergeIn(Result);
+ BBLV.mergeIn(Result, DL);
}
}
}
ConstantInt *CI = dyn_cast<ConstantInt>(ICI->getOperand(1));
if (CI && (ICI->getOperand(0) == Val || NegOffset)) {
- // Calculate the range of values that would satisfy the comparison.
+ // Calculate the range of values that are allowed by the comparison
ConstantRange CmpRange(CI->getValue());
ConstantRange TrueValues =
- ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange);
+ ConstantRange::makeAllowedICmpRegion(ICI->getPredicate(), CmpRange);
if (NegOffset) // Apply the offset from above.
TrueValues = TrueValues.subtract(NegOffset->getValue());
// LazyValueInfo Impl
//===----------------------------------------------------------------------===//
-/// getCache - This lazily constructs the LazyValueInfoCache.
+/// This lazily constructs the LazyValueInfoCache.
static LazyValueInfoCache &getCache(void *&PImpl, AssumptionCache *AC,
- const DataLayout *DL = nullptr,
+ const DataLayout *DL,
DominatorTree *DT = nullptr) {
- if (!PImpl)
- PImpl = new LazyValueInfoCache(AC, DL, DT);
+ if (!PImpl) {
+ assert(DL && "getCache() called with a null DataLayout");
+ PImpl = new LazyValueInfoCache(AC, *DL, DT);
+ }
return *static_cast<LazyValueInfoCache*>(PImpl);
}
bool LazyValueInfo::runOnFunction(Function &F) {
AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+ const DataLayout &DL = F.getParent()->getDataLayout();
DominatorTreeWrapperPass *DTWP =
getAnalysisIfAvailable<DominatorTreeWrapperPass>();
DT = DTWP ? &DTWP->getDomTree() : nullptr;
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- DL = DLP ? &DLP->getDataLayout() : nullptr;
-
- TLI = &getAnalysis<TargetLibraryInfo>();
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
if (PImpl)
- getCache(PImpl, AC, DL, DT).clear();
+ getCache(PImpl, AC, &DL, DT).clear();
// Fully lazy.
return false;
void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<AssumptionCacheTracker>();
- AU.addRequired<TargetLibraryInfo>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
}
void LazyValueInfo::releaseMemory() {
// If the cache was allocated, free it.
if (PImpl) {
- delete &getCache(PImpl, AC);
+ delete &getCache(PImpl, AC, nullptr);
PImpl = nullptr;
}
}
Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB,
Instruction *CxtI) {
+ const DataLayout &DL = BB->getModule()->getDataLayout();
LVILatticeVal Result =
- getCache(PImpl, AC, DL, DT).getValueInBlock(V, BB, CxtI);
+ getCache(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
if (Result.isConstant())
return Result.getConstant();
return nullptr;
}
-/// getConstantOnEdge - Determine whether the specified value is known to be a
+/// Determine whether the specified value is known to be a
/// constant on the specified edge. Return null if not.
Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,
BasicBlock *ToBB,
Instruction *CxtI) {
+ const DataLayout &DL = FromBB->getModule()->getDataLayout();
LVILatticeVal Result =
- getCache(PImpl, AC, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
+ getCache(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
if (Result.isConstant())
return Result.getConstant();
return nullptr;
}
-static LazyValueInfo::Tristate
-getPredicateResult(unsigned Pred, Constant *C, LVILatticeVal &Result,
- const DataLayout *DL, TargetLibraryInfo *TLI) {
+static LazyValueInfo::Tristate getPredicateResult(unsigned Pred, Constant *C,
+ LVILatticeVal &Result,
+ const DataLayout &DL,
+ TargetLibraryInfo *TLI) {
// If we know the value is a constant, evaluate the conditional.
Constant *Res = nullptr;
return LazyValueInfo::Unknown;
}
-/// getPredicateOnEdge - Determine whether the specified value comparison
-/// with a constant is known to be true or false on the specified CFG edge.
-/// Pred is a CmpInst predicate.
+/// Determine whether the specified value comparison with a constant is known to
+/// be true or false on the specified CFG edge. Pred is a CmpInst predicate.
LazyValueInfo::Tristate
LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
BasicBlock *FromBB, BasicBlock *ToBB,
Instruction *CxtI) {
+ const DataLayout &DL = FromBB->getModule()->getDataLayout();
LVILatticeVal Result =
- getCache(PImpl, AC, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
+ getCache(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
return getPredicateResult(Pred, C, Result, DL, TLI);
}
LazyValueInfo::Tristate
LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
Instruction *CxtI) {
- LVILatticeVal Result = getCache(PImpl, AC, DL, DT).getValueAt(V, CxtI);
-
- return getPredicateResult(Pred, C, Result, DL, TLI);
+ const DataLayout &DL = CxtI->getModule()->getDataLayout();
+ LVILatticeVal Result = getCache(PImpl, AC, &DL, DT).getValueAt(V, CxtI);
+ Tristate Ret = getPredicateResult(Pred, C, Result, DL, TLI);
+ if (Ret != Unknown)
+ return Ret;
+
+ // TODO: Move this logic inside getValueAt so that it can be cached rather
+ // than re-queried on each call. This would also allow us to merge the
+ // underlying lattice values to get more information
+ if (CxtI) {
+ // For a comparison where the V is outside this block, it's possible
+ // that we've branched on it before. Look to see if the value is known
+ // on all incoming edges.
+ BasicBlock *BB = CxtI->getParent();
+ pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
+ if (PI != PE &&
+ (!isa<Instruction>(V) ||
+ cast<Instruction>(V)->getParent() != BB)) {
+ // For predecessor edge, determine if the comparison is true or false
+ // on that edge. If they're all true or all false, we can conclude
+ // the value of the comparison in this block.
+ Tristate Baseline = getPredicateOnEdge(Pred, V, C, *PI, BB, CxtI);
+ if (Baseline != Unknown) {
+ // Check that all remaining incoming values match the first one.
+ while (++PI != PE) {
+ Tristate Ret = getPredicateOnEdge(Pred, V, C, *PI, BB, CxtI);
+ if (Ret != Baseline) break;
+ }
+ // If we terminated early, then one of the values didn't match.
+ if (PI == PE) {
+ return Baseline;
+ }
+ }
+ }
+ }
+ return Unknown;
}
void LazyValueInfo::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc,
BasicBlock *NewSucc) {
- if (PImpl)
- getCache(PImpl, AC, DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
+ if (PImpl) {
+ const DataLayout &DL = PredBB->getModule()->getDataLayout();
+ getCache(PImpl, AC, &DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
+ }
}
void LazyValueInfo::eraseBlock(BasicBlock *BB) {
- if (PImpl)
- getCache(PImpl, AC, DL, DT).eraseBlock(BB);
+ if (PImpl) {
+ const DataLayout &DL = BB->getModule()->getDataLayout();
+ getCache(PImpl, AC, &DL, DT).eraseBlock(BB);
+ }
}
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