1//===- llvm/MC/MCLinkerOptimizationHint.cpp ----- LOH handling ------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "llvm/MC/MCLinkerOptimizationHint.h"
10#include "llvm/MC/MCMachObjectWriter.h"
11#include "llvm/Support/LEB128.h"
12#include "llvm/Support/raw_ostream.h"
13#include <cstddef>
14#include <cstdint>
15
16using namespace llvm;
17
18// Each LOH is composed by, in this order (each field is encoded using ULEB128):
19// - Its kind.
20// - Its number of arguments (let say N).
21// - Its arg1.
22// - ...
23// - Its argN.
24// <arg1> to <argN> are absolute addresses in the object file, i.e.,
25// relative addresses from the beginning of the object file.
26void MCLOHDirective::emit_impl(raw_ostream &OutStream,
27 const MachObjectWriter &ObjWriter
28
29) const {
30 encodeULEB128(Value: Kind, OS&: OutStream);
31 encodeULEB128(Value: Args.size(), OS&: OutStream);
32 for (const MCSymbol *Arg : Args)
33 encodeULEB128(Value: ObjWriter.getSymbolAddress(S: *Arg), OS&: OutStream);
34}
35
36void MCLOHDirective::emit(const MCAssembler &Asm,
37 MachObjectWriter &ObjWriter) const {
38 raw_ostream &OutStream = ObjWriter.W.OS;
39 emit_impl(OutStream, ObjWriter);
40}
41
42uint64_t MCLOHDirective::getEmitSize(const MCAssembler &Asm,
43 const MachObjectWriter &ObjWriter) const {
44 class raw_counting_ostream : public raw_ostream {
45 uint64_t Count = 0;
46
47 void write_impl(const char *, size_t size) override { Count += size; }
48
49 uint64_t current_pos() const override { return Count; }
50
51 public:
52 raw_counting_ostream() = default;
53 ~raw_counting_ostream() override { flush(); }
54 };
55
56 raw_counting_ostream OutStream;
57 emit_impl(OutStream, ObjWriter);
58 return OutStream.tell();
59}
60