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https://github.com/c64scene-ar/llvm-6502.git
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5af401d5f1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24083 91177308-0d34-0410-b5e6-96231b3b80d8
92 lines
3.6 KiB
C++
92 lines
3.6 KiB
C++
//===- TransformInternals.cpp - Implement shared functions for transforms -===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines shared functions used by the different components of the
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// Transforms library.
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//
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//===----------------------------------------------------------------------===//
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#include "TransformInternals.h"
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#include "llvm/Type.h"
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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using namespace llvm;
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static const Type *getStructOffsetStep(const StructType *STy, uint64_t &Offset,
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std::vector<Value*> &Indices,
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const TargetData &TD) {
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assert(Offset < TD.getTypeSize(STy) && "Offset not in composite!");
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const StructLayout *SL = TD.getStructLayout(STy);
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// This loop terminates always on a 0 <= i < MemberOffsets.size()
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unsigned i;
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for (i = 0; i < SL->MemberOffsets.size()-1; ++i)
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if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1])
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break;
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assert(Offset >= SL->MemberOffsets[i] &&
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(i == SL->MemberOffsets.size()-1 || Offset < SL->MemberOffsets[i+1]));
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// Make sure to save the current index...
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Indices.push_back(ConstantUInt::get(Type::UIntTy, i));
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Offset = SL->MemberOffsets[i];
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return STy->getContainedType(i);
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}
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// getStructOffsetType - Return a vector of offsets that are to be used to index
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// into the specified struct type to get as close as possible to index as we
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// can. Note that it is possible that we cannot get exactly to Offset, in which
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// case we update offset to be the offset we actually obtained. The resultant
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// leaf type is returned.
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//
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// If StopEarly is set to true (the default), the first object with the
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// specified type is returned, even if it is a struct type itself. In this
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// case, this routine will not drill down to the leaf type. Set StopEarly to
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// false if you want a leaf
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//
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const Type *llvm::getStructOffsetType(const Type *Ty, unsigned &Offset,
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std::vector<Value*> &Indices,
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const TargetData &TD, bool StopEarly) {
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if (Offset == 0 && StopEarly && !Indices.empty())
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return Ty; // Return the leaf type
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uint64_t ThisOffset;
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const Type *NextType;
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if (const StructType *STy = dyn_cast<StructType>(Ty)) {
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if (STy->getNumElements()) {
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Offset = 0;
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return STy;
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}
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ThisOffset = Offset;
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NextType = getStructOffsetStep(STy, ThisOffset, Indices, TD);
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} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
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assert(Offset == 0 || Offset < TD.getTypeSize(ATy) &&
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"Offset not in composite!");
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NextType = ATy->getElementType();
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unsigned ChildSize = (unsigned)TD.getTypeSize(NextType);
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if (ConstantSInt::isValueValidForType(Type::IntTy, Offset/ChildSize))
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Indices.push_back(ConstantSInt::get(Type::IntTy, Offset/ChildSize));
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else
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Indices.push_back(ConstantSInt::get(Type::LongTy, Offset/ChildSize));
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ThisOffset = (Offset/ChildSize)*ChildSize;
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} else {
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Offset = 0; // Return the offset that we were able to achieve
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return Ty; // Return the leaf type
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}
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unsigned SubOffs = unsigned(Offset - ThisOffset);
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const Type *LeafTy = getStructOffsetType(NextType, SubOffs,
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Indices, TD, StopEarly);
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Offset = unsigned(ThisOffset + SubOffs);
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return LeafTy;
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}
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