mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Giacomo Vercesi
ab125b35b0
Change company name to "rev.ng Labs Srl" in all license headers to reflect changed company name and legal status Add missing license headers to files that didn't have one
80 lines
2.6 KiB
C++
80 lines
2.6 KiB
C++
//
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// Copyright rev.ng Labs Srl. See LICENSE.md for details.
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//
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#include "revng/Support/Assert.h"
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#include "revng/Support/Debug.h"
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#include "revng-c/DataLayoutAnalysis/DLATypeSystem.h"
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#include "FieldSizeComputation.h"
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uint64_t getFieldSize(const dla::LayoutTypeSystemNode *Child,
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const dla::TypeLinkTag *EdgeTag) {
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uint64_t Result = 0LL;
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auto ChildSize = Child->Size;
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revng_assert(ChildSize > 0LL);
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switch (EdgeTag->getKind()) {
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case dla::TypeLinkTag::LK_Instance: {
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const dla::OffsetExpression &OE = EdgeTag->getOffsetExpr();
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revng_assert(OE.Strides.size() == OE.TripCounts.size());
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// Ignore stuff at negative offsets.
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revng_assert(OE.Offset >= 0LL);
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// If we have an array, we have to compute its size, taking into
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// account the strides and the trip counts.
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// In an OffsetExpression the larger strides come first, so we need to build
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// the instance bottom-up, in reverse, starting from the smaller strides.
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int64_t PrevStride = 0LL;
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for (const auto &[TripCount, Stride] :
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llvm::reverse(llvm::zip(OE.TripCounts, OE.Strides))) {
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revng_assert(not PrevStride or PrevStride < Stride);
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revng_assert(Stride > 0LL);
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auto StrideSize = static_cast<uint64_t>(Stride);
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// If we have a TripCount, we expect it to be strictly positive.
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revng_assert(not TripCount.has_value() or TripCount.value() > 0LL);
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// Arrays with unknown numbers of elements are considered as if
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// they had a single element
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auto NumElems = TripCount.has_value() ? TripCount.value() : 1;
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revng_assert(NumElems);
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// Here we are computing the larger size that is known to be
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// accessed. So if we have an array, we consider it to be one
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// element shorter than expected, and we add ChildSize only once
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// at the end.
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// This is equivalent to:
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// ChildSize = (NumElems * StrideSize) - (StrideSize - ChildSize);
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ChildSize = ((NumElems - 1) * StrideSize) + ChildSize;
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}
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revng_assert(ChildSize);
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Result = ChildSize;
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} break;
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default:
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revng_unreachable("unexpected edge");
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}
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return Result;
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}
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uint64_t getFieldUpperMember(const dla::LayoutTypeSystemNode *Child,
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const dla::TypeLinkTag *EdgeTag) {
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auto ChildSize = getFieldSize(Child, EdgeTag);
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revng_assert(ChildSize > 0LL);
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int64_t ChildOffset = 0LL;
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if (EdgeTag->getKind() == dla::TypeLinkTag::LK_Instance) {
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const dla::OffsetExpression &OE = EdgeTag->getOffsetExpr();
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ChildOffset = std::max<int64_t>(OE.Offset, ChildOffset);
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}
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return ChildOffset + ChildSize;
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}
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