llvm-mirror/lib/MC/MCLinkerOptimizationHint.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

60 lines
2.0 KiB
C++

//===- 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();
}