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//===-- Operator.cpp - Implement the LLVM operators -----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the non-inline methods for the LLVM Operator classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Operator.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/Instructions.h"
#include "ConstantsContext.h"
namespace llvm {
bool Operator::hasPoisonGeneratingFlags() const {
switch (getOpcode()) {
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::Shl: {
auto *OBO = cast<OverflowingBinaryOperator>(this);
return OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap();
}
case Instruction::Trunc: {
if (auto *TI = dyn_cast<TruncInst>(this))
return TI->hasNoUnsignedWrap() || TI->hasNoSignedWrap();
return false;
}
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::AShr:
case Instruction::LShr:
return cast<PossiblyExactOperator>(this)->isExact();
case Instruction::Or:
return cast<PossiblyDisjointInst>(this)->isDisjoint();
case Instruction::GetElementPtr: {
auto *GEP = cast<GEPOperator>(this);
// Note: inrange exists on constexpr only
return GEP->isInBounds() || GEP->getInRange() != std::nullopt;
}
case Instruction::UIToFP:
case Instruction::ZExt:
if (auto *NNI = dyn_cast<PossiblyNonNegInst>(this))
return NNI->hasNonNeg();
return false;
default:
if (const auto *FP = dyn_cast<FPMathOperator>(this))
return FP->hasNoNaNs() || FP->hasNoInfs();
return false;
}
}
bool Operator::hasPoisonGeneratingFlagsOrMetadata() const {
if (hasPoisonGeneratingFlags())
return true;
auto *I = dyn_cast<Instruction>(this);
return I && I->hasPoisonGeneratingMetadata();
}
Type *GEPOperator::getSourceElementType() const {
if (auto *I = dyn_cast<GetElementPtrInst>(this))
return I->getSourceElementType();
return cast<GetElementPtrConstantExpr>(this)->getSourceElementType();
}
Type *GEPOperator::getResultElementType() const {
if (auto *I = dyn_cast<GetElementPtrInst>(this))
return I->getResultElementType();
return cast<GetElementPtrConstantExpr>(this)->getResultElementType();
}
std::optional<ConstantRange> GEPOperator::getInRange() const {
if (auto *CE = dyn_cast<GetElementPtrConstantExpr>(this))
return CE->getInRange();
return std::nullopt;
}
Align GEPOperator::getMaxPreservedAlignment(const DataLayout &DL) const {
/// compute the worse possible offset for every level of the GEP et accumulate
/// the minimum alignment into Result.
Align Result = Align(llvm::Value::MaximumAlignment);
for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
GTI != GTE; ++GTI) {
uint64_t Offset;
ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
if (StructType *STy = GTI.getStructTypeOrNull()) {
const StructLayout *SL = DL.getStructLayout(STy);
Offset = SL->getElementOffset(OpC->getZExtValue());
} else {
assert(GTI.isSequential() && "should be sequencial");
/// If the index isn't known, we take 1 because it is the index that will
/// give the worse alignment of the offset.
const uint64_t ElemCount = OpC ? OpC->getZExtValue() : 1;
Offset = GTI.getSequentialElementStride(DL) * ElemCount;
}
Result = Align(MinAlign(Offset, Result.value()));
}
return Result;
}
bool GEPOperator::accumulateConstantOffset(
const DataLayout &DL, APInt &Offset,
function_ref<bool(Value &, APInt &)> ExternalAnalysis) const {
assert(Offset.getBitWidth() ==
DL.getIndexSizeInBits(getPointerAddressSpace()) &&
"The offset bit width does not match DL specification.");
SmallVector<const Value *> Index(llvm::drop_begin(operand_values()));
return GEPOperator::accumulateConstantOffset(getSourceElementType(), Index,
DL, Offset, ExternalAnalysis);
}
bool GEPOperator::accumulateConstantOffset(
Type *SourceType, ArrayRef<const Value *> Index, const DataLayout &DL,
APInt &Offset, function_ref<bool(Value &, APInt &)> ExternalAnalysis) {
// Fast path for canonical getelementptr i8 form.
if (SourceType->isIntegerTy(8) && !ExternalAnalysis) {
if (auto *CI = dyn_cast<ConstantInt>(Index.front())) {
Offset += CI->getValue().sextOrTrunc(Offset.getBitWidth());
return true;
}
return false;
}
bool UsedExternalAnalysis = false;
auto AccumulateOffset = [&](APInt Index, uint64_t Size) -> bool {
Index = Index.sextOrTrunc(Offset.getBitWidth());
APInt IndexedSize = APInt(Offset.getBitWidth(), Size);
// For array or vector indices, scale the index by the size of the type.
if (!UsedExternalAnalysis) {
Offset += Index * IndexedSize;
} else {
// External Analysis can return a result higher/lower than the value
// represents. We need to detect overflow/underflow.
bool Overflow = false;
APInt OffsetPlus = Index.smul_ov(IndexedSize, Overflow);
if (Overflow)
return false;
Offset = Offset.sadd_ov(OffsetPlus, Overflow);
if (Overflow)
return false;
}
return true;
};
auto begin = generic_gep_type_iterator<decltype(Index.begin())>::begin(
SourceType, Index.begin());
auto end = generic_gep_type_iterator<decltype(Index.end())>::end(Index.end());
for (auto GTI = begin, GTE = end; GTI != GTE; ++GTI) {
// Scalable vectors are multiplied by a runtime constant.
bool ScalableType = GTI.getIndexedType()->isScalableTy();
Value *V = GTI.getOperand();
StructType *STy = GTI.getStructTypeOrNull();
// Handle ConstantInt if possible.
if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
if (ConstOffset->isZero())
continue;
// if the type is scalable and the constant is not zero (vscale * n * 0 =
// 0) bailout.
if (ScalableType)
return false;
// Handle a struct index, which adds its field offset to the pointer.
if (STy) {
unsigned ElementIdx = ConstOffset->getZExtValue();
const StructLayout *SL = DL.getStructLayout(STy);
// Element offset is in bytes.
if (!AccumulateOffset(
APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)),
1))
return false;
continue;
}
if (!AccumulateOffset(ConstOffset->getValue(),
GTI.getSequentialElementStride(DL)))
return false;
continue;
}
// The operand is not constant, check if an external analysis was provided.
// External analsis is not applicable to a struct type.
if (!ExternalAnalysis || STy || ScalableType)
return false;
APInt AnalysisIndex;
if (!ExternalAnalysis(*V, AnalysisIndex))
return false;
UsedExternalAnalysis = true;
if (!AccumulateOffset(AnalysisIndex, GTI.getSequentialElementStride(DL)))
return false;
}
return true;
}
bool GEPOperator::collectOffset(
const DataLayout &DL, unsigned BitWidth,
MapVector<Value *, APInt> &VariableOffsets,
APInt &ConstantOffset) const {
assert(BitWidth == DL.getIndexSizeInBits(getPointerAddressSpace()) &&
"The offset bit width does not match DL specification.");
auto CollectConstantOffset = [&](APInt Index, uint64_t Size) {
Index = Index.sextOrTrunc(BitWidth);
APInt IndexedSize = APInt(BitWidth, Size);
ConstantOffset += Index * IndexedSize;
};
for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
GTI != GTE; ++GTI) {
// Scalable vectors are multiplied by a runtime constant.
bool ScalableType = GTI.getIndexedType()->isScalableTy();
Value *V = GTI.getOperand();
StructType *STy = GTI.getStructTypeOrNull();
// Handle ConstantInt if possible.
if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
if (ConstOffset->isZero())
continue;
// If the type is scalable and the constant is not zero (vscale * n * 0 =
// 0) bailout.
// TODO: If the runtime value is accessible at any point before DWARF
// emission, then we could potentially keep a forward reference to it
// in the debug value to be filled in later.
if (ScalableType)
return false;
// Handle a struct index, which adds its field offset to the pointer.
if (STy) {
unsigned ElementIdx = ConstOffset->getZExtValue();
const StructLayout *SL = DL.getStructLayout(STy);
// Element offset is in bytes.
CollectConstantOffset(APInt(BitWidth, SL->getElementOffset(ElementIdx)),
1);
continue;
}
CollectConstantOffset(ConstOffset->getValue(),
GTI.getSequentialElementStride(DL));
continue;
}
if (STy || ScalableType)
return false;
APInt IndexedSize = APInt(BitWidth, GTI.getSequentialElementStride(DL));
// Insert an initial offset of 0 for V iff none exists already, then
// increment the offset by IndexedSize.
if (!IndexedSize.isZero()) {
auto *It = VariableOffsets.insert({V, APInt(BitWidth, 0)}).first;
It->second += IndexedSize;
}
}
return true;
}
void FastMathFlags::print(raw_ostream &O) const {
if (all())
O << " fast";
else {
if (allowReassoc())
O << " reassoc";
if (noNaNs())
O << " nnan";
if (noInfs())
O << " ninf";
if (noSignedZeros())
O << " nsz";
if (allowReciprocal())
O << " arcp";
if (allowContract())
O << " contract";
if (approxFunc())
O << " afn";
}
}
} // namespace llvm