1//===- MCAsmInfoDarwin.cpp - Darwin asm properties ------------------------===//
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// This file defines target asm properties related what form asm statements
10// should take in general on Darwin-based targets
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/MC/MCAsmInfoDarwin.h"
15#include "llvm/BinaryFormat/MachO.h"
16#include "llvm/MC/MCDirectives.h"
17#include "llvm/MC/MCSectionMachO.h"
18
19using namespace llvm;
20
21bool MCAsmInfoDarwin::isSectionAtomizableBySymbols(
22    const MCSection &Section) const {
23  const MCSectionMachO &SMO = static_cast<const MCSectionMachO &>(Section);
24
25  // Sections holding 1 byte strings are atomized based on the data they
26  // contain.
27  // Sections holding 2 byte strings require symbols in order to be atomized.
28  // There is no dedicated section for 4 byte strings.
29  if (SMO.getType() == MachO::S_CSTRING_LITERALS)
30    return false;
31
32  if (SMO.getSegmentName() == "__DATA" && SMO.getName() == "__cfstring")
33    return false;
34
35  if (SMO.getSegmentName() == "__DATA" && SMO.getName() == "__objc_classrefs")
36    return false;
37
38  switch (SMO.getType()) {
39  default:
40    return true;
41
42  // These sections are atomized at the element boundaries without using
43  // symbols.
44  case MachO::S_4BYTE_LITERALS:
45  case MachO::S_8BYTE_LITERALS:
46  case MachO::S_16BYTE_LITERALS:
47  case MachO::S_LITERAL_POINTERS:
48  case MachO::S_NON_LAZY_SYMBOL_POINTERS:
49  case MachO::S_LAZY_SYMBOL_POINTERS:
50  case MachO::S_THREAD_LOCAL_VARIABLE_POINTERS:
51  case MachO::S_MOD_INIT_FUNC_POINTERS:
52  case MachO::S_MOD_TERM_FUNC_POINTERS:
53  case MachO::S_INTERPOSING:
54    return false;
55  }
56}
57
58MCAsmInfoDarwin::MCAsmInfoDarwin() {
59  // Common settings for all Darwin targets.
60  // Syntax:
61  LinkerPrivateGlobalPrefix = "l";
62  HasSingleParameterDotFile = false;
63  HasSubsectionsViaSymbols = true;
64
65  AlignmentIsInBytes = false;
66  COMMDirectiveAlignmentIsInBytes = false;
67  LCOMMDirectiveAlignmentType = LCOMM::Log2Alignment;
68  InlineAsmStart = " InlineAsm Start";
69  InlineAsmEnd = " InlineAsm End";
70
71  // Directives:
72  HasWeakDefDirective = true;
73  HasWeakDefCanBeHiddenDirective = true;
74  WeakRefDirective = "\t.weak_reference ";
75  ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
76  HasMachoZeroFillDirective = true;  // Uses .zerofill
77  HasMachoTBSSDirective = true; // Uses .tbss
78
79  // FIXME: Change this once MC is the system assembler.
80  HasAggressiveSymbolFolding = false;
81
82  HiddenVisibilityAttr = MCSA_PrivateExtern;
83  HiddenDeclarationVisibilityAttr = MCSA_Invalid;
84
85  // Doesn't support protected visibility.
86  ProtectedVisibilityAttr = MCSA_Invalid;
87
88  HasDotTypeDotSizeDirective = false;
89  HasNoDeadStrip = true;
90  HasAltEntry = true;
91
92  DwarfUsesRelocationsAcrossSections = false;
93  SetDirectiveSuppressesReloc = true;
94}
95