60 lines
2.0 KiB
C++
60 lines
2.0 KiB
C++
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//===- llvm/MC/MCLinkerOptimizationHint.cpp ----- LOH handling ------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCLinkerOptimizationHint.h"
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#include "llvm/MC/MCAsmLayout.h"
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#include "llvm/MC/MCMachObjectWriter.h"
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#include "llvm/Support/LEB128.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cstddef>
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#include <cstdint>
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using namespace llvm;
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// Each LOH is composed by, in this order (each field is encoded using ULEB128):
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// - Its kind.
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// - Its number of arguments (let say N).
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// - Its arg1.
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// - ...
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// - Its argN.
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// <arg1> to <argN> are absolute addresses in the object file, i.e.,
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// relative addresses from the beginning of the object file.
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void MCLOHDirective::emit_impl(raw_ostream &OutStream,
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const MachObjectWriter &ObjWriter,
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const MCAsmLayout &Layout) const {
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encodeULEB128(Kind, OutStream);
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encodeULEB128(Args.size(), OutStream);
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for (const MCSymbol *Arg : Args)
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encodeULEB128(ObjWriter.getSymbolAddress(*Arg, Layout), OutStream);
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}
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void MCLOHDirective::emit(MachObjectWriter &ObjWriter,
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const MCAsmLayout &Layout) const {
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raw_ostream &OutStream = ObjWriter.W.OS;
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emit_impl(OutStream, ObjWriter, Layout);
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}
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uint64_t MCLOHDirective::getEmitSize(const MachObjectWriter &ObjWriter,
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const MCAsmLayout &Layout) const {
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class raw_counting_ostream : public raw_ostream {
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uint64_t Count = 0;
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void write_impl(const char *, size_t size) override { Count += size; }
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uint64_t current_pos() const override { return Count; }
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public:
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raw_counting_ostream() = default;
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~raw_counting_ostream() override { flush(); }
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};
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raw_counting_ostream OutStream;
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emit_impl(OutStream, ObjWriter, Layout);
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return OutStream.tell();
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}
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