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#include "slang-ir-extract-value-from-type.h"
#include "slang-ir-layout.h"
#include "slang-ir-insts.h"
#define CHECK(x) SLANG_RELEASE_ASSERT((x) == SLANG_OK)
namespace Slang
{
// Represents the result of finding the leaf-level value in a type that contains the
// the entirety or the first half of the requested value at the specified offset.
struct FindLeafValueResult
{
IRInst* leafValue = nullptr; // The leaf-level value.
uint32_t valueSize = 0; // The size of the leaf-level value.
uint32_t offsetInValue = 0; // The offset in bytes within `leafValue` that contains the requested value.
};
FindLeafValueResult findLeafValueAtOffset(
TargetRequest* targetReq,
IRBuilder& builder,
IRType* dataType,
IRSizeAndAlignment& layout,
IRInst* src,
uint32_t offset)
{
FindLeafValueResult result;
if (offset >= layout.size && offset < layout.getStride())
{
// We are extracting bits beyond the type size but within the stride boundary,
// return a 0 value in this case.
result.leafValue = builder.getIntValue(builder.getUIntType(), 0);
result.valueSize = 4;
result.offsetInValue = (uint32_t)(offset - layout.size);
return result;
}
switch (dataType->getOp())
{
case kIROp_StructType:
{
auto structType = as<IRStructType>(dataType);
for (auto field : structType->getFields())
{
IRIntegerValue fieldOffset = 0;
IRSizeAndAlignment fieldLayout;
CHECK(getNaturalSizeAndAlignment(targetReq, field->getFieldType(), &fieldLayout));
CHECK(getNaturalOffset(targetReq, field, &fieldOffset));
if (fieldOffset + fieldLayout.size > offset)
{
if (fieldOffset > offset)
{
// This field is starting after the requested offset,
// therefore the requested value is located at the "gap"
// between aligned fields, in this case the requested value
// is 0.
result.leafValue = builder.getIntValue(builder.getUIntType(), 0);
result.valueSize = 4;
result.offsetInValue = (uint32_t)(fieldOffset - offset);
return result;
}
// The field contains requested value. We want to recursively
// traverse the field type to reach a leaf case.
auto fieldValue =
builder.emitFieldExtract(field->getFieldType(), src, field->getKey());
return findLeafValueAtOffset(
targetReq,
builder,
field->getFieldType(),
fieldLayout,
fieldValue,
(uint32_t)(offset - fieldOffset));
}
}
result.leafValue = builder.getIntValue(builder.getUIntType(), 0);
result.valueSize = 4;
result.offsetInValue = (uint32_t)(offset - layout.size);
return result;
}
break;
case kIROp_ArrayType:
{
auto arrayType = as<IRArrayType>(dataType);
auto elementType = arrayType->getElementType();
IRSizeAndAlignment elementLayout;
CHECK(getNaturalSizeAndAlignment(targetReq, elementType, &elementLayout));
if (elementLayout.getStride() == 0)
{
result.leafValue = builder.getIntValue(builder.getUIntType(), 0);
result.valueSize = 4;
result.offsetInValue = 0;
return result;
}
uint32_t index = offset / (uint32_t)elementLayout.getStride();
auto elementValue = builder.emitElementExtract(
elementType, src, builder.getIntValue(builder.getUIntType(), index));
return findLeafValueAtOffset(
targetReq,
builder,
elementType,
elementLayout,
elementValue,
(uint32_t)(offset - elementLayout.getStride() * index));
}
break;
case kIROp_VectorType:
{
auto vectorType = as<IRVectorType>(dataType);
auto elementType = vectorType->getElementType();
IRSizeAndAlignment elementLayout;
CHECK(getNaturalSizeAndAlignment(targetReq, elementType, &elementLayout));
uint32_t index =
elementLayout.getStride() == 0 ? 0 : (uint32_t)(offset / elementLayout.getStride());
auto elementValue = builder.emitElementExtract(
elementType, src, builder.getIntValue(builder.getUIntType(), index));
return findLeafValueAtOffset(
targetReq,
builder,
elementType,
elementLayout,
elementValue,
(uint32_t)(offset - elementLayout.getStride() * index));
}
break;
case kIROp_MatrixType:
{
// Note: this code is assuming row major odering.
auto matrixType = as<IRMatrixType>(dataType);
auto elementType = matrixType->getElementType();
SLANG_RELEASE_ASSERT(matrixType->getColumnCount()->getOp() == kIROp_IntLit);
auto columnCount = as<IRIntLit>(matrixType->getColumnCount())->value.intVal;
auto rowType = builder.getVectorType(elementType, matrixType->getColumnCount());
IRSizeAndAlignment rowLayout;
CHECK(getNaturalSizeAndAlignment(targetReq, rowType, &rowLayout));
uint32_t rowIndex = rowLayout.getStride() == 0
? 0
: (uint32_t)(offset / (columnCount * rowLayout.getStride()));
auto rowValue = builder.emitElementExtract(
rowType, src, builder.getIntValue(builder.getUIntType(), rowIndex));
return findLeafValueAtOffset(
targetReq,
builder,
rowType,
rowLayout,
rowValue,
(uint32_t)(offset - rowLayout.getStride() * rowIndex));
}
break;
default:
{
result.leafValue = src;
result.offsetInValue = offset;
result.valueSize = (uint32_t)layout.size;
return result;
}
break;
}
}
IRInst* extractByteAtOffset(
IRBuilder& builder,
TargetRequest* targetReq,
IRType* dataType,
IRSizeAndAlignment& layout,
IRInst* src,
uint32_t offset)
{
auto leaf = findLeafValueAtOffset(targetReq, builder, dataType, layout, src, offset);
IRType* uintType = nullptr;
if (leaf.valueSize <= 4)
{
uintType = builder.getUIntType();
}
else
{
uintType = builder.getUInt64Type();
}
auto resultValue = builder.emitBitCast(uintType, leaf.leafValue);
if (leaf.offsetInValue != 0)
{
uint32_t shift = leaf.offsetInValue * 8;
resultValue = builder.emitShr(uintType, resultValue, builder.getIntValue(uintType, shift));
resultValue = builder.emitBitAnd(
builder.getUIntType(),
resultValue, builder.getIntValue(builder.getUIntType(), 0xFF));
}
return resultValue;
}
IRInst* extractMultiByteValueAtOffset(
IRBuilder& builder,
TargetRequest* targetReq,
IRType* dataType,
IRSizeAndAlignment& layout,
IRInst* src,
uint32_t size,
uint32_t offset)
{
if (size == 1)
return extractByteAtOffset(builder, targetReq, dataType, layout, src, offset);
auto leaf = findLeafValueAtOffset(targetReq, builder, dataType, layout, src, offset);
auto resultValue = leaf.leafValue;
IRType* uintType = nullptr;
if (leaf.valueSize <= 4)
{
uintType = builder.getUIntType();
}
else
{
uintType = builder.getUInt64Type();
}
if (leaf.valueSize - leaf.offsetInValue >= size)
{
// The request value is fully contained in the found leaf element.
// We can proceed to extract the requested bits from the element.
uint32_t shift = leaf.offsetInValue * 8;
if (shift > 0)
resultValue = builder.emitShr(uintType, resultValue, builder.getIntValue(uintType, shift));
uint32_t bitMask = 0;
switch (size)
{
case 1:
bitMask = 0xFF;
break;
case 2:
bitMask = 0xFFFFF;
break;
case 3:
bitMask = 0xFFFFFF;
break;
case 4:
bitMask = 0xFFFFFFFF;
break;
default:
break;
}
if (leaf.valueSize != size)
{
resultValue =
builder.emitBitAnd(uintType, resultValue, builder.getIntValue(uintType, bitMask));
}
return resultValue;
}
else
{
// The requested value crosses the boundaries of different fields.
// We need to extract first and second half separately, and combine them together.
auto firstHalf = extractMultiByteValueAtOffset(
builder, targetReq, dataType, layout, src, size / 2, offset);
auto secondHalf = extractMultiByteValueAtOffset(
builder, targetReq, dataType, layout, src, size / 2, offset + size / 2);
uint32_t shift = (size / 2) * 8;
resultValue = builder.emitAdd(
builder.getUIntType(),
firstHalf,
builder.emitShl(
builder.getUIntType(),
secondHalf,
builder.getIntValue(builder.getUIntType(), shift)));
return resultValue;
}
}
IRInst* extractValueAtOffset(
IRBuilder& builder, TargetRequest* targetReq, IRInst* src, uint32_t offset, uint32_t size)
{
auto dataType = src->getDataType();
IRSizeAndAlignment typeLayout;
SLANG_RETURN_NULL_ON_FAIL(getNaturalSizeAndAlignment(targetReq, dataType, &typeLayout));
if (offset + size > typeLayout.size)
{
return builder.getIntValue(builder.getIntType(), 0);
}
return extractMultiByteValueAtOffset(
builder, targetReq, dataType, typeLayout, src, size, offset);
}
} // namespace Slang
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