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 enum DefaultOnOff { Default, Enable, Disable };
24 static cl::opt<DefaultOnOff> DwarfExtendedLoc(
25 "dwarf-extended-loc", cl::Hidden,
26 cl::desc("Disable emission of the extended flags in .loc directives."),
27 cl::values(clEnumVal(Default, "Default for platform"),
28 clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
29 cl::init(Default));
30
31 cl::opt<cl::boolOrDefault> UseLEB128Directives(
32 "use-leb128-directives", cl::Hidden,
33 cl::desc(
34 "Disable the usage of LEB128 directives, and generate .byte instead."),
35 cl::init(cl::BOU_UNSET));
36
MCAsmInfo()37 MCAsmInfo::MCAsmInfo() {
38 SeparatorString = ";";
39 CommentString = "#";
40 LabelSuffix = ":";
41 PrivateGlobalPrefix = "L";
42 PrivateLabelPrefix = PrivateGlobalPrefix;
43 LinkerPrivateGlobalPrefix = "";
44 InlineAsmStart = "APP";
45 InlineAsmEnd = "NO_APP";
46 Code16Directive = ".code16";
47 Code32Directive = ".code32";
48 Code64Directive = ".code64";
49 ZeroDirective = "\t.zero\t";
50 AsciiDirective = "\t.ascii\t";
51 AscizDirective = "\t.asciz\t";
52 Data8bitsDirective = "\t.byte\t";
53 Data16bitsDirective = "\t.short\t";
54 Data32bitsDirective = "\t.long\t";
55 Data64bitsDirective = "\t.quad\t";
56 GlobalDirective = "\t.globl\t";
57 WeakDirective = "\t.weak\t";
58 if (DwarfExtendedLoc != Default)
59 SupportsExtendedDwarfLocDirective = DwarfExtendedLoc == Enable;
60 if (UseLEB128Directives != cl::BOU_UNSET)
61 HasLEB128Directives = UseLEB128Directives == cl::BOU_TRUE;
62
63 // FIXME: Clang's logic should be synced with the logic used to initialize
64 // this member and the two implementations should be merged.
65 // For reference:
66 // - Solaris always enables the integrated assembler by default
67 // - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case
68 // - Windows always enables the integrated assembler by default
69 // - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft?
70 // - MachO targets always enables the integrated assembler by default
71 // - MCAsmInfoDarwin is handling this case
72 // - Generic_GCC toolchains enable the integrated assembler on a per
73 // architecture basis.
74 // - The target subclasses for AArch64, ARM, and X86 handle these cases
75 UseIntegratedAssembler = true;
76 PreserveAsmComments = true;
77 }
78
79 MCAsmInfo::~MCAsmInfo() = default;
80
addInitialFrameState(const MCCFIInstruction & Inst)81 void MCAsmInfo::addInitialFrameState(const MCCFIInstruction &Inst) {
82 InitialFrameState.push_back(Inst);
83 }
84
isSectionAtomizableBySymbols(const MCSection & Section) const85 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
86 return false;
87 }
88
89 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const90 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
91 unsigned Encoding,
92 MCStreamer &Streamer) const {
93 return getExprForFDESymbol(Sym, Encoding, Streamer);
94 }
95
96 const MCExpr *
getExprForFDESymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const97 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
98 unsigned Encoding,
99 MCStreamer &Streamer) const {
100 if (!(Encoding & dwarf::DW_EH_PE_pcrel))
101 return MCSymbolRefExpr::create(Sym, Streamer.getContext());
102
103 MCContext &Context = Streamer.getContext();
104 const MCExpr *Res = MCSymbolRefExpr::create(Sym, Context);
105 MCSymbol *PCSym = Context.createTempSymbol();
106 Streamer.emitLabel(PCSym);
107 const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
108 return MCBinaryExpr::createSub(Res, PC, Context);
109 }
110
isAcceptableChar(char C) const111 bool MCAsmInfo::isAcceptableChar(char C) const {
112 return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z') ||
113 (C >= '0' && C <= '9') || C == '_' || C == '$' || C == '.' || C == '@';
114 }
115
isValidUnquotedName(StringRef Name) const116 bool MCAsmInfo::isValidUnquotedName(StringRef Name) const {
117 if (Name.empty())
118 return false;
119
120 // If any of the characters in the string is an unacceptable character, force
121 // quotes.
122 for (char C : Name) {
123 if (!isAcceptableChar(C))
124 return false;
125 }
126
127 return true;
128 }
129
shouldOmitSectionDirective(StringRef SectionName) const130 bool MCAsmInfo::shouldOmitSectionDirective(StringRef SectionName) const {
131 // FIXME: Does .section .bss/.data/.text work everywhere??
132 return SectionName == ".text" || SectionName == ".data" ||
133 (SectionName == ".bss" && !usesELFSectionDirectiveForBSS());
134 }
135