mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alessandro Di Federico
79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
//
|
|
// This file is distributed under the MIT License. See LICENSE.md for details.
|
|
//
|
|
|
|
#include "revng/DataLayoutAnalysis/DLATypeSystem.h"
|
|
#include "revng/Support/Assert.h"
|
|
#include "revng/Support/Debug.h"
|
|
|
|
#include "FieldSizeComputation.h"
|
|
|
|
uint64_t getFieldSize(const dla::LayoutTypeSystemNode *Child,
|
|
const dla::TypeLinkTag *EdgeTag) {
|
|
uint64_t Result = 0ULL;
|
|
|
|
auto ChildSize = Child->Size;
|
|
revng_assert(ChildSize > 0ULL);
|
|
|
|
switch (EdgeTag->getKind()) {
|
|
|
|
case dla::TypeLinkTag::LK_Instance: {
|
|
const dla::OffsetExpression &OE = EdgeTag->getOffsetExpr();
|
|
revng_assert(OE.Strides.size() == OE.TripCounts.size());
|
|
|
|
// Ignore stuff at negative offsets.
|
|
revng_assert(OE.Offset >= 0ULL);
|
|
|
|
// If we have an array, we have to compute its size, taking into
|
|
// account the strides and the trip counts.
|
|
// In an OffsetExpression the larger strides come first, so we need to build
|
|
// the instance bottom-up, in reverse, starting from the smaller strides.
|
|
uint64_t PrevStride = 0ULL;
|
|
for (const auto &[TripCount, Stride] :
|
|
llvm::reverse(llvm::zip(OE.TripCounts, OE.Strides))) {
|
|
|
|
revng_assert(not PrevStride or PrevStride < Stride);
|
|
revng_assert(Stride > 0ULL);
|
|
auto StrideSize = Stride;
|
|
|
|
// If we have a TripCount, we expect it to be strictly positive.
|
|
revng_assert(not TripCount.has_value() or TripCount.value() > 0ULL);
|
|
|
|
// Arrays with unknown numbers of elements are considered as if
|
|
// they had a single element
|
|
auto NumElems = TripCount.has_value() ? TripCount.value() : 1;
|
|
revng_assert(NumElems);
|
|
|
|
// Here we are computing the larger size that is known to be
|
|
// accessed. So if we have an array, we consider it to be one
|
|
// element shorter than expected, and we add ChildSize only once
|
|
// at the end.
|
|
// This is equivalent to:
|
|
// ChildSize = (NumElems * StrideSize) - (StrideSize - ChildSize);
|
|
ChildSize = ((NumElems - 1) * StrideSize) + ChildSize;
|
|
}
|
|
|
|
revng_assert(ChildSize);
|
|
Result = ChildSize;
|
|
} break;
|
|
|
|
default:
|
|
revng_unreachable("unexpected edge");
|
|
}
|
|
|
|
return Result;
|
|
}
|
|
|
|
uint64_t getFieldUpperMember(const dla::LayoutTypeSystemNode *Child,
|
|
const dla::TypeLinkTag *EdgeTag) {
|
|
auto ChildSize = getFieldSize(Child, EdgeTag);
|
|
revng_assert(ChildSize > 0ULL);
|
|
|
|
uint64_t ChildOffset = 0ULL;
|
|
if (EdgeTag->getKind() == dla::TypeLinkTag::LK_Instance) {
|
|
const dla::OffsetExpression &OE = EdgeTag->getOffsetExpr();
|
|
ChildOffset = std::max<int64_t>(OE.Offset, ChildOffset);
|
|
}
|
|
return ChildOffset + ChildSize;
|
|
}
|