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/ADT/StringExtras.h"
16 #include "llvm/BinaryFormat/Dwarf.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/MC/MCStreamer.h"
20 #include "llvm/MC/MCValue.h"
21 #include "llvm/Support/Casting.h"
22 #include "llvm/Support/CommandLine.h"
23
24 using namespace llvm;
25
26 namespace {
27 enum DefaultOnOff { Default, Enable, Disable };
28 }
29 static cl::opt<DefaultOnOff> DwarfExtendedLoc(
30 "dwarf-extended-loc", cl::Hidden,
31 cl::desc("Disable emission of the extended flags in .loc directives."),
32 cl::values(clEnumVal(Default, "Default for platform"),
33 clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
34 cl::init(Default));
35
36 namespace llvm {
37 cl::opt<cl::boolOrDefault> UseLEB128Directives(
38 "use-leb128-directives", cl::Hidden,
39 cl::desc(
40 "Disable the usage of LEB128 directives, and generate .byte instead."),
41 cl::init(cl::BOU_UNSET));
42 }
43
MCAsmInfo()44 MCAsmInfo::MCAsmInfo() {
45 SeparatorString = ";";
46 CommentString = "#";
47 LabelSuffix = ":";
48 PrivateGlobalPrefix = "L";
49 PrivateLabelPrefix = PrivateGlobalPrefix;
50 LinkerPrivateGlobalPrefix = "";
51 InlineAsmStart = "APP";
52 InlineAsmEnd = "NO_APP";
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 UseIntegratedAssembler = true;
67 ParseInlineAsmUsingAsmParser = false;
68 PreserveAsmComments = true;
69 PPCUseFullRegisterNames = false;
70 }
71
72 MCAsmInfo::~MCAsmInfo() = default;
73
addInitialFrameState(const MCCFIInstruction & Inst)74 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
75 InitialFrameState.push_back(Inst);
76 }
77
78 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const79 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
80 unsigned Encoding,
81 MCStreamer &Streamer) const {
82 return getExprForFDESymbol(Sym, Encoding, Streamer);
83 }
84
85 const MCExpr *
getExprForFDESymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const86 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
87 unsigned Encoding,
88 MCStreamer &Streamer) const {
89 if (!(Encoding & dwarf::DW_EH_PE_pcrel))
90 return MCSymbolRefExpr::create(Sym, Streamer.getContext());
91
92 MCContext &Context = Streamer.getContext();
93 const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
94 MCSymbol *PCSym = Context.createTempSymbol();
95 Streamer.emitLabel(PCSym);
96 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
97 return MCBinaryExpr::createSub(Res, PC, Context);
98 }
99
isAcceptableChar(char C) const100 bool MCAsmInfo::isAcceptableChar(char C) const {
101 if (C == '@')
102 return doesAllowAtInName();
103
104 return isAlnum(C) || C == '_' || C == '$' || C == '.';
105 }
106
isValidUnquotedName(StringRef Name) const107 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
108 if (Name.empty())
109 return false;
110
111 // If any of the characters in the string is an unacceptable character, force
112 // quotes.
113 for (char C : Name) {
114 if (!isAcceptableChar(C))
115 return false;
116 }
117
118 return true;
119 }
120
shouldOmitSectionDirective(StringRef SectionName) const121 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
122 // FIXME: Does .section .bss/.data/.text work everywhere??
123 return SectionName == ".text" || SectionName == ".data" ||
124 (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
125 }
126
initializeAtSpecifiers(ArrayRef<AtSpecifier> Descs)127 void MCAsmInfo::initializeAtSpecifiers(ArrayRef<AtSpecifier> Descs) {
128 assert(AtSpecifierToName.empty() && "cannot initialize twice");
129 for (auto Desc : Descs) {
130 [[maybe_unused]] auto It =
131 AtSpecifierToName.try_emplace(Desc.Kind, Desc.Name);
132 assert(It.second && "duplicate Kind");
133 [[maybe_unused]] auto It2 =
134 NameToAtSpecifier.try_emplace(Desc.Name.lower(), Desc.Kind);
135 assert(It2.second);
136 }
137 }
138
getSpecifierName(uint32_t S) const139 StringRef MCAsmInfo::getSpecifierName(uint32_t S) const {
140 auto It = AtSpecifierToName.find(S);
141 assert(It != AtSpecifierToName.end() &&
142 "ensure the specifier is set in initializeVariantKinds");
143 return It->second;
144 }
145
getSpecifierForName(StringRef Name) const146 std::optional<uint32_t> MCAsmInfo::getSpecifierForName(StringRef Name) const {
147 auto It = NameToAtSpecifier.find(Name.lower());
148 if (It != NameToAtSpecifier.end())
149 return It->second;
150 return {};
151 }
152
printExpr(raw_ostream & OS,const MCExpr & Expr) const153 void MCAsmInfo::printExpr(raw_ostream &OS, const MCExpr &Expr) const {
154 if (auto *SE = dyn_cast<MCSpecifierExpr>(&Expr))
155 printSpecifierExpr(OS, *SE);
156 else
157 Expr.print(OS, this);
158 }
159
evaluateAsRelocatableImpl(const MCSpecifierExpr & E,MCValue & Res,const MCAssembler * Asm) const160 bool MCAsmInfo::evaluateAsRelocatableImpl(const MCSpecifierExpr &E,
161 MCValue &Res,
162 const MCAssembler *Asm) const {
163 if (!E.getSubExpr()->evaluateAsRelocatable(Res, Asm))
164 return false;
165
166 Res.setSpecifier(E.getSpecifier());
167 return !Res.getSubSym();
168 }
169