1 //===-- MCAsmInfo.cpp - Asm Info -------------------------------------------==//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines target asm properties related what form asm statements
11 // should take.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/MC/MCAsmInfo.h"
16 #include "llvm/MC/MCContext.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/Support/Dwarf.h"
21 #include <cctype>
22 #include <cstring>
23 using namespace llvm;
24 
MCAsmInfo()25 MCAsmInfo::MCAsmInfo() {
26   PointerSize = 4;
27   CalleeSaveStackSlotSize = 4;
28 
29   IsLittleEndian = true;
30   StackGrowsUp = false;
31   HasSubsectionsViaSymbols = false;
32   HasMachoZeroFillDirective = false;
33   HasMachoTBSSDirective = false;
34   HasStaticCtorDtorReferenceInStaticMode = false;
35   MaxInstLength = 4;
36   MinInstAlignment = 1;
37   DollarIsPC = false;
38   SeparatorString = ";";
39   CommentString = "#";
40   LabelSuffix = ":";
41   UseAssignmentForEHBegin = false;
42   NeedsLocalForSize = false;
43   PrivateGlobalPrefix = "L";
44   PrivateLabelPrefix = PrivateGlobalPrefix;
45   LinkerPrivateGlobalPrefix = "";
46   InlineAsmStart = "APP";
47   InlineAsmEnd = "NO_APP";
48   Code16Directive = ".code16";
49   Code32Directive = ".code32";
50   Code64Directive = ".code64";
51   AssemblerDialect = 0;
52   AllowAtInName = false;
53   UseDataRegionDirectives = false;
54   ZeroDirective = "\t.zero\t";
55   AsciiDirective = "\t.ascii\t";
56   AscizDirective = "\t.asciz\t";
57   Data8bitsDirective = "\t.byte\t";
58   Data16bitsDirective = "\t.short\t";
59   Data32bitsDirective = "\t.long\t";
60   Data64bitsDirective = "\t.quad\t";
61   SunStyleELFSectionSwitchSyntax = false;
62   UsesELFSectionDirectiveForBSS = false;
63   AlignmentIsInBytes = true;
64   TextAlignFillValue = 0;
65   GPRel64Directive = nullptr;
66   GPRel32Directive = nullptr;
67   GlobalDirective = "\t.globl\t";
68   SetDirectiveSuppressesReloc = false;
69   HasAggressiveSymbolFolding = true;
70   COMMDirectiveAlignmentIsInBytes = true;
71   LCOMMDirectiveAlignmentType = LCOMM::NoAlignment;
72   HasFunctionAlignment = true;
73   HasDotTypeDotSizeDirective = true;
74   HasSingleParameterDotFile = true;
75   HasIdentDirective = false;
76   HasNoDeadStrip = false;
77   WeakDirective = "\t.weak\t";
78   WeakRefDirective = nullptr;
79   HasWeakDefDirective = false;
80   HasWeakDefCanBeHiddenDirective = false;
81   HasLinkOnceDirective = false;
82   HiddenVisibilityAttr = MCSA_Hidden;
83   HiddenDeclarationVisibilityAttr = MCSA_Hidden;
84   ProtectedVisibilityAttr = MCSA_Protected;
85   SupportsDebugInformation = false;
86   ExceptionsType = ExceptionHandling::None;
87   WinEHEncodingType = WinEH::EncodingType::Invalid;
88   DwarfUsesRelocationsAcrossSections = true;
89   DwarfFDESymbolsUseAbsDiff = false;
90   DwarfRegNumForCFI = false;
91   NeedsDwarfSectionOffsetDirective = false;
92   UseParensForSymbolVariant = false;
93 
94   // FIXME: Clang's logic should be synced with the logic used to initialize
95   //        this member and the two implementations should be merged.
96   // For reference:
97   // - Solaris always enables the integrated assembler by default
98   //   - SparcELFMCAsmInfo and X86ELFMCAsmInfo are handling this case
99   // - Windows always enables the integrated assembler by default
100   //   - MCAsmInfoCOFF is handling this case, should it be MCAsmInfoMicrosoft?
101   // - MachO targets always enables the integrated assembler by default
102   //   - MCAsmInfoDarwin is handling this case
103   // - Generic_GCC toolchains enable the integrated assembler on a per
104   //   architecture basis.
105   //   - The target subclasses for AArch64, ARM, and X86 handle these cases
106   UseIntegratedAssembler = false;
107 
108   CompressDebugSections = false;
109 }
110 
~MCAsmInfo()111 MCAsmInfo::~MCAsmInfo() {
112 }
113 
isSectionAtomizableBySymbols(const MCSection & Section) const114 bool MCAsmInfo::isSectionAtomizableBySymbols(const MCSection &Section) const {
115   return false;
116 }
117 
118 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const119 MCAsmInfo::getExprForPersonalitySymbol(const MCSymbol *Sym,
120                                        unsigned Encoding,
121                                        MCStreamer &Streamer) const {
122   return getExprForFDESymbol(Sym, Encoding, Streamer);
123 }
124 
125 const MCExpr *
getExprForFDESymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const126 MCAsmInfo::getExprForFDESymbol(const MCSymbol *Sym,
127                                unsigned Encoding,
128                                MCStreamer &Streamer) const {
129   if (!(Encoding & dwarf::DW_EH_PE_pcrel))
130     return MCSymbolRefExpr::Create(Sym, Streamer.getContext());
131 
132   MCContext &Context = Streamer.getContext();
133   const MCExpr *Res = MCSymbolRefExpr::Create(Sym, Context);
134   MCSymbol *PCSym = Context.CreateTempSymbol();
135   Streamer.EmitLabel(PCSym);
136   const MCExpr *PC = MCSymbolRefExpr::Create(PCSym, Context);
137   return MCBinaryExpr::CreateSub(Res, PC, Context);
138 }
139