99 lines
2.8 KiB
C++
99 lines
2.8 KiB
C++
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//===- subzero/src/IceFixups.cpp - Implementation of Assembler Fixups -----===//
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//
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// The Subzero Code Generator
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief Implements the AssemblerFixup class, a very basic target-independent
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/// representation of a fixup or relocation.
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///
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//===----------------------------------------------------------------------===//
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#include "IceFixups.h"
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#include "IceOperand.h"
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namespace Ice {
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const Constant *AssemblerFixup::NullSymbol = nullptr;
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RelocOffsetT AssemblerFixup::offset() const {
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if (isNullSymbol())
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return addend_;
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if (!ValueIsSymbol) {
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if (const auto *CR = llvm::dyn_cast<ConstantRelocatable>(ConstValue))
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return CR->getOffset() + addend_;
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}
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return addend_;
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}
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GlobalString AssemblerFixup::symbol() const {
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assert(!isNullSymbol());
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assert(!ValueIsSymbol);
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const Constant *C = ConstValue;
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if (const auto *CR = llvm::dyn_cast<ConstantRelocatable>(C)) {
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return CR->getName();
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}
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// NOTE: currently only float/doubles are put into constant pools. In the
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// future we may put integers as well.
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assert(llvm::isa<ConstantFloat>(C) || llvm::isa<ConstantDouble>(C));
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return C->getLabelName();
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}
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size_t AssemblerFixup::emit(GlobalContext *Ctx, const Assembler &Asm) const {
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static constexpr const size_t FixupSize = 4;
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if (!BuildDefs::dump())
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return FixupSize;
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Ostream &Str = Ctx->getStrEmit();
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Str << "\t.long ";
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std::string Symbol;
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if (isNullSymbol()) {
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Str << "__Sz_AbsoluteZero";
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} else {
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Symbol = symbol().toString();
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Str << Symbol;
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assert(!ValueIsSymbol);
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if (const auto *CR = llvm::dyn_cast<ConstantRelocatable>(ConstValue)) {
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if (!Asm.fixupIsPCRel(kind()) && getFlags().getUseNonsfi() &&
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CR->getName().toString() != GlobalOffsetTable) {
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Str << "@GOTOFF";
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}
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}
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}
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assert(Asm.load<RelocOffsetT>(position()) == 0);
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RelocOffsetT Offset = offset();
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if (Offset != 0) {
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if (Offset > 0) {
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Str << " + " << Offset;
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} else {
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assert(Offset != std::numeric_limits<RelocOffsetT>::lowest());
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Str << " - " << -Offset;
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}
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}
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// We need to emit the '- .' for PCRel fixups. Even if the relocation kind()
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// is not PCRel, we emit the '- .' for the _GLOBAL_OFFSET_TABLE_.
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// TODO(jpp): create fixups wrt the GOT with the right fixup kind.
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if (Asm.fixupIsPCRel(kind()) || Symbol == GlobalOffsetTable)
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Str << " - .";
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Str << "\n";
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return FixupSize;
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}
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void AssemblerFixup::emitOffset(Assembler *Asm) const {
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Asm->store(position(), offset());
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}
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size_t AssemblerTextFixup::emit(GlobalContext *Ctx, const Assembler &) const {
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Ctx->getStrEmit() << Message << "\n";
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return NumBytes;
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}
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} // end of namespace Ice
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