1//===- MCAsmInfo.cpp - Asm Info -------------------------------------------===//
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.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/MC/MCAsmInfo.h"
15#include "llvm/BinaryFormat/Dwarf.h"
16#include "llvm/MC/MCContext.h"
17#include "llvm/MC/MCExpr.h"
18#include "llvm/MC/MCStreamer.h"
19#include "llvm/Support/CommandLine.h"
20
21using namespace llvm;
22
23namespace {
24enum DefaultOnOff { Default, Enable, Disable };
25}
26static cl::opt<DefaultOnOff> DwarfExtendedLoc(
27    "dwarf-extended-loc", cl::Hidden,
28    cl::desc("Disable emission of the extended flags in .loc directives."),
29    cl::values(clEnumVal(Default, "Default for platform"),
30               clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
31    cl::init(Default));
32
33namespace llvm {
34cl::opt<cl::boolOrDefault> UseLEB128Directives(
35    "use-leb128-directives", cl::Hidden,
36    cl::desc(
37        "Disable the usage of LEB128 directives, and generate .byte instead."),
38    cl::init(cl::BOU_UNSET));
39}
40
41MCAsmInfo::MCAsmInfo() {
42  SeparatorString = ";";
43  CommentString = "#";
44  LabelSuffix = ":";
45  PrivateGlobalPrefix = "L";
46  PrivateLabelPrefix = PrivateGlobalPrefix;
47  LinkerPrivateGlobalPrefix = "";
48  InlineAsmStart = "APP";
49  InlineAsmEnd = "NO_APP";
50  Code16Directive = ".code16";
51  Code32Directive = ".code32";
52  Code64Directive = ".code64";
53  ZeroDirective = "\t.zero\t";
54  AsciiDirective = "\t.ascii\t";
55  AscizDirective = "\t.asciz\t";
56  Data8bitsDirective = "\t.byte\t";
57  Data16bitsDirective = "\t.short\t";
58  Data32bitsDirective = "\t.long\t";
59  Data64bitsDirective = "\t.quad\t";
60  GlobalDirective = "\t.globl\t";
61  WeakDirective = "\t.weak\t";
62  if (DwarfExtendedLoc != Default)
63    SupportsExtendedDwarfLocDirective = DwarfExtendedLoc == Enable;
64  if (UseLEB128Directives != cl::BOU_UNSET)
65    HasLEB128Directives = UseLEB128Directives == cl::BOU_TRUE;
66
67  // FIXME: Clang's logic should be synced with the logic used to initialize
68  //        this member and the two implementations should be merged.
69  // For reference:
70  // - Solaris always enables the integrated assembler by default
71  //   - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case
72  // - Windows always enables the integrated assembler by default
73  //   - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft?
74  // - MachO targets always enables the integrated assembler by default
75  //   - MCAsmInfoDarwin is handling this case
76  // - Generic_GCC toolchains enable the integrated assembler on a per
77  //   architecture basis.
78  //   - The target subclasses for AArch64, ARM, and X86 handle these cases
79  UseIntegratedAssembler = true;
80  ParseInlineAsmUsingAsmParser = false;
81  PreserveAsmComments = true;
82}
83
84MCAsmInfo::~MCAsmInfo() = default;
85
86void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
87  InitialFrameState.push_back(Inst);
88}
89
90bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
91  return false;
92}
93
94const MCExpr *
95MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
96                                       unsigned Encoding,
97                                       MCStreamer &Streamer) const {
98  return getExprForFDESymbol(Sym, Encoding, Streamer);
99}
100
101const MCExpr *
102MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
103                               unsigned Encoding,
104                               MCStreamer &Streamer) const {
105  if (!(Encoding & dwarf::DW_EH_PE_pcrel))
106    return MCSymbolRefExpr::create(Sym, Streamer.getContext());
107
108  MCContext &Context = Streamer.getContext();
109  const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
110  MCSymbol *PCSym = Context.createTempSymbol();
111  Streamer.emitLabel(PCSym);
112  const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
113  return MCBinaryExpr::createSub(Res, PC, Context);
114}
115
116bool MCAsmInfo::isAcceptableChar(char C) const {
117  if (C == '@')
118    return doesAllowAtInName();
119
120  return isAlnum(C) || C == '_' || C == '$' || C == '.';
121}
122
123bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
124  if (Name.empty())
125    return false;
126
127  // If any of the characters in the string is an unacceptable character, force
128  // quotes.
129  for (char C : Name) {
130    if (!isAcceptableChar(C))
131      return false;
132  }
133
134  return true;
135}
136
137bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
138  // FIXME: Does .section .bss/.data/.text work everywhere??
139  return SectionName == ".text" || SectionName == ".data" ||
140        (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
141}
142