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
21 using namespace llvm;
22
23 namespace {
24 enum DefaultOnOff { Default, Enable, Disable };
25 }
26 static 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
33 namespace llvm {
34 cl::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
MCAsmInfo()41 MCAsmInfo::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 PreserveAsmComments = true;
81 }
82
83 MCAsmInfo::~MCAsmInfo() = default;
84
addInitialFrameState(const MCCFIInstruction & Inst)85 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
86 InitialFrameState.push_back(Inst);
87 }
88
isSectionAtomizableBySymbols(const MCSection & Section) const89 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
90 return false;
91 }
92
93 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const94 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
95 unsigned Encoding,
96 MCStreamer &Streamer) const {
97 return getExprForFDESymbol(Sym, Encoding, Streamer);
98 }
99
100 const MCExpr *
getExprForFDESymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const101 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
102 unsigned Encoding,
103 MCStreamer &Streamer) const {
104 if (!(Encoding & dwarf::DW_EH_PE_pcrel))
105 return MCSymbolRefExpr::create(Sym, Streamer.getContext());
106
107 MCContext &Context = Streamer.getContext();
108 const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
109 MCSymbol *PCSym = Context.createTempSymbol();
110 Streamer.emitLabel(PCSym);
111 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
112 return MCBinaryExpr::createSub(Res, PC, Context);
113 }
114
isAcceptableChar(char C) const115 bool MCAsmInfo::isAcceptableChar(char C) const {
116 return isAlnum(C) || C == '_' || C == '$' || C == '.' || C == '@';
117 }
118
isValidUnquotedName(StringRef Name) const119 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
120 if (Name.empty())
121 return false;
122
123 // If any of the characters in the string is an unacceptable character, force
124 // quotes.
125 for (char C : Name) {
126 if (!isAcceptableChar(C))
127 return false;
128 }
129
130 return true;
131 }
132
shouldOmitSectionDirective(StringRef SectionName) const133 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
134 // FIXME: Does .section .bss/.data/.text work everywhere??
135 return SectionName == ".text" || SectionName == ".data" ||
136 (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
137 }
138