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