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.getSectionName() == "__cfstring")
33    return false;
34
35  if (SMO.getSegmentName() == "__DATA" &&
36      SMO.getSectionName() == "__objc_classrefs")
37    return false;
38
39  switch (SMO.getType()) {
40  default:
41    return true;
42
43  // These sections are atomized at the element boundaries without using
44  // symbols.
45  case MachO::S_4BYTE_LITERALS:
46  case MachO::S_8BYTE_LITERALS:
47  case MachO::S_16BYTE_LITERALS:
48  case MachO::S_LITERAL_POINTERS:
49  case MachO::S_NON_LAZY_SYMBOL_POINTERS:
50  case MachO::S_LAZY_SYMBOL_POINTERS:
51  case MachO::S_THREAD_LOCAL_VARIABLE_POINTERS:
52  case MachO::S_MOD_INIT_FUNC_POINTERS:
53  case MachO::S_MOD_TERM_FUNC_POINTERS:
54  case MachO::S_INTERPOSING:
55    return false;
56  }
57}
58
59MCAsmInfoDarwin::MCAsmInfoDarwin() {
60  // Common settings for all Darwin targets.
61  // Syntax:
62  LinkerPrivateGlobalPrefix = "l";
63  HasSingleParameterDotFile = false;
64  HasSubsectionsViaSymbols = true;
65
66  AlignmentIsInBytes = false;
67  COMMDirectiveAlignmentIsInBytes = false;
68  LCOMMDirectiveAlignmentType = LCOMM::Log2Alignment;
69  InlineAsmStart = " InlineAsm Start";
70  InlineAsmEnd = " InlineAsm End";
71
72  // Directives:
73  HasWeakDefDirective = true;
74  HasWeakDefCanBeHiddenDirective = true;
75  WeakRefDirective = "\t.weak_reference ";
76  ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
77  HasMachoZeroFillDirective = true;  // Uses .zerofill
78  HasMachoTBSSDirective = true; // Uses .tbss
79
80  // FIXME: Change this once MC is the system assembler.
81  HasAggressiveSymbolFolding = false;
82
83  HiddenVisibilityAttr = MCSA_PrivateExtern;
84  HiddenDeclarationVisibilityAttr = MCSA_Invalid;
85
86  // Doesn't support protected visibility.
87  ProtectedVisibilityAttr = MCSA_Invalid;
88
89  HasDotTypeDotSizeDirective = false;
90  HasNoDeadStrip = true;
91  HasAltEntry = true;
92
93  DwarfUsesRelocationsAcrossSections = false;
94
95  UseIntegratedAssembler = true;
96  SetDirectiveSuppressesReloc = true;
97}
98