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[DL] Inline getAlignmentInfo() implementation (NFC)

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Apart from getting the entry in the table (which is already a
separate function), the remaining logic is different for all
alignment types and is better combined with getAlignment().

This is a minor efficiency improvement, and should make further
improvements like using separate storage for different alignment
types simpler.
This commit is contained in:
Nikita Popov
2020-11-30 18:33:07 +01:00
parent fe43168348
commit b5f23189fb
2 changed files with 56 additions and 67 deletions
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113
llvm/lib/IR/DataLayout.cpp
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@@ -620,47 +620,16 @@ Error DataLayout::setPointerAlignment(uint32_t AddrSpace, Align ABIAlign,
return Error::success();
}
/// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
/// preferred if ABIInfo = false) the layout wants for the specified datatype.
Align DataLayout::getAlignmentInfo(AlignTypeEnum AlignType, uint32_t BitWidth,
bool ABIInfo, Type *Ty) const {
AlignmentsTy::const_iterator I = findAlignmentLowerBound(AlignType, BitWidth);
// See if we found an exact match. Of if we are looking for an integer type,
// but don't have an exact match take the next largest integer. This is where
// the lower_bound will point to when it fails an exact match.
if (I != Alignments.end() && I->AlignType == (unsigned)AlignType &&
(I->TypeBitWidth == BitWidth || AlignType == INTEGER_ALIGN))
return ABIInfo ? I->ABIAlign : I->PrefAlign;
if (AlignType == INTEGER_ALIGN) {
// If we didn't have a larger value try the largest value we have.
if (I != Alignments.begin()) {
--I; // Go to the previous entry and see if its an integer.
if (I->AlignType == INTEGER_ALIGN)
return ABIInfo ? I->ABIAlign : I->PrefAlign;
}
} else if (AlignType == VECTOR_ALIGN) {
// By default, use natural alignment for vector types. This is consistent
// with what clang and llvm-gcc do.
unsigned Alignment =
getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
// We're only calculating a natural alignment, so it doesn't have to be
// based on the full size for scalable vectors. Using the minimum element
// count should be enough here.
Alignment *= cast<VectorType>(Ty)->getElementCount().getKnownMinValue();
Alignment = PowerOf2Ceil(Alignment);
return Align(Alignment);
}
// If we still couldn't find a reasonable default alignment, fall back
// to a simple heuristic that the alignment is the first power of two
// greater-or-equal to the store size of the type. This is a reasonable
// approximation of reality, and if the user wanted something less
// less conservative, they should have specified it explicitly in the data
// layout.
unsigned Alignment = getTypeStoreSize(Ty);
Alignment = PowerOf2Ceil(Alignment);
return Align(Alignment);
Align DataLayout::getIntegerAlignment(uint32_t BitWidth,
bool abi_or_pref) const {
auto I = findAlignmentLowerBound(INTEGER_ALIGN, BitWidth);
// If we don't have an exact match, use alignment of next larger integer
// type. If there is none, use alignment of largest integer type by going
// back one element.
if (I == Alignments.end() || I->AlignType != INTEGER_ALIGN)
--I;
assert(I->AlignType == INTEGER_ALIGN && "Must be integer alignment");
return abi_or_pref ? I->ABIAlign : I->PrefAlign;
}
namespace {
@@ -768,8 +737,6 @@ unsigned DataLayout::getIndexTypeSizeInBits(Type *Ty) const {
== false) for the requested type \a Ty.
*/
Align DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
AlignTypeEnum AlignType;
assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
switch (Ty->getTypeID()) {
// Early escape for the non-numeric types.
@@ -790,12 +757,15 @@ Align DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
// Get the layout annotation... which is lazily created on demand.
const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
const Align Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
const LayoutAlignElem &AggregateAlign = Alignments[0];
assert(AggregateAlign.AlignType == AGGREGATE_ALIGN &&
"Aggregate alignment must be first alignment entry");
const Align Align =
abi_or_pref ? AggregateAlign.ABIAlign : AggregateAlign.PrefAlign;
return std::max(Align, Layout->getAlignment());
}
case Type::IntegerTyID:
AlignType = INTEGER_ALIGN;
break;
return getIntegerAlignment(Ty->getIntegerBitWidth(), abi_or_pref);
case Type::HalfTyID:
case Type::BFloatTyID:
case Type::FloatTyID:
@@ -804,22 +774,45 @@ Align DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
// same size and alignment, so they look the same here.
case Type::PPC_FP128TyID:
case Type::FP128TyID:
case Type::X86_FP80TyID:
AlignType = FLOAT_ALIGN;
break;
case Type::X86_FP80TyID: {
unsigned BitWidth = getTypeSizeInBits(Ty).getFixedSize();
auto I = findAlignmentLowerBound(FLOAT_ALIGN, BitWidth);
if (I != Alignments.end() && I->AlignType == FLOAT_ALIGN &&
I->TypeBitWidth == BitWidth)
return abi_or_pref ? I->ABIAlign : I->PrefAlign;
// If we still couldn't find a reasonable default alignment, fall back
// to a simple heuristic that the alignment is the first power of two
// greater-or-equal to the store size of the type. This is a reasonable
// approximation of reality, and if the user wanted something less
// less conservative, they should have specified it explicitly in the data
// layout.
return Align(PowerOf2Ceil(BitWidth / 8));
}
case Type::X86_MMXTyID:
case Type::FixedVectorTyID:
case Type::ScalableVectorTyID:
AlignType = VECTOR_ALIGN;
break;
case Type::ScalableVectorTyID: {
unsigned BitWidth = getTypeSizeInBits(Ty).getKnownMinSize();
auto I = findAlignmentLowerBound(VECTOR_ALIGN, BitWidth);
if (I != Alignments.end() && I->AlignType == VECTOR_ALIGN &&
I->TypeBitWidth == BitWidth)
return abi_or_pref ? I->ABIAlign : I->PrefAlign;
// By default, use natural alignment for vector types. This is consistent
// with what clang and llvm-gcc do.
// TODO: This should probably not be using the alloc size.
unsigned Alignment =
getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
// We're only calculating a natural alignment, so it doesn't have to be
// based on the full size for scalable vectors. Using the minimum element
// count should be enough here.
Alignment *= cast<VectorType>(Ty)->getElementCount().getKnownMinValue();
Alignment = PowerOf2Ceil(Alignment);
return Align(Alignment);
}
default:
llvm_unreachable("Bad type for getAlignment!!!");
}
// If we're dealing with a scalable vector, we just need the known minimum
// size for determining alignment. If not, we'll get the exact size.
return getAlignmentInfo(AlignType, getTypeSizeInBits(Ty).getKnownMinSize(),
abi_or_pref, Ty);
}
/// TODO: Remove this function once the transition to Align is over.
@@ -831,12 +824,6 @@ Align DataLayout::getABITypeAlign(Type *Ty) const {
return getAlignment(Ty, true);
}
/// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
/// an integer type of the specified bitwidth.
Align DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, nullptr);
}
/// TODO: Remove this function once the transition to Align is over.
unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
return getPrefTypeAlign(Ty).value();