X86MCAsmInfo.cpp revision 243830 
1//===-- X86MCAsmInfo.cpp - X86 asm properties -----------------------------===//
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 contains the declarations of the X86MCAsmInfo properties.
11//
12//===----------------------------------------------------------------------===//
13
14#include "X86MCAsmInfo.h"
15#include "llvm/ADT/Triple.h"
16#include "llvm/MC/MCContext.h"
17#include "llvm/MC/MCExpr.h"
18#include "llvm/MC/MCSectionELF.h"
19#include "llvm/MC/MCStreamer.h"
20#include "llvm/Support/CommandLine.h"
21#include "llvm/Support/ELF.h"
22using namespace llvm;
23
24enum AsmWriterFlavorTy {
25  // Note: This numbering has to match the GCC assembler dialects for inline
26  // asm alternatives to work right.
27  ATT = 0, Intel = 1
28};
29
30static cl::opt<AsmWriterFlavorTy>
31AsmWriterFlavor("x86-asm-syntax", cl::init(ATT),
32  cl::desc("Choose style of code to emit from X86 backend:"),
33  cl::values(clEnumValN(ATT,   "att",   "Emit AT&T-style assembly"),
34             clEnumValN(Intel, "intel", "Emit Intel-style assembly"),
35             clEnumValEnd));
36
37static cl::opt<bool>
38MarkedJTDataRegions("mark-data-regions", cl::init(false),
39  cl::desc("Mark code section jump table data regions."),
40  cl::Hidden);
41
42void X86MCAsmInfoDarwin::anchor() { }
43
44X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
45  bool is64Bit = T.getArch() == Triple::x86_64;
46  if (is64Bit)
47    PointerSize = 8;
48
49  AssemblerDialect = AsmWriterFlavor;
50
51  TextAlignFillValue = 0x90;
52
53  if (!is64Bit)
54    Data64bitsDirective = 0;       // we can't emit a 64-bit unit
55
56  // Use ## as a comment string so that .s files generated by llvm can go
57  // through the GCC preprocessor without causing an error.  This is needed
58  // because "clang foo.s" runs the C preprocessor, which is usually reserved
59  // for .S files on other systems.  Perhaps this is because the file system
60  // wasn't always case preserving or something.
61  CommentString = "##";
62  PCSymbol = ".";
63
64  SupportsDebugInformation = true;
65  DwarfUsesInlineInfoSection = true;
66  UseDataRegionDirectives = MarkedJTDataRegions;
67
68  // Exceptions handling
69  ExceptionsType = ExceptionHandling::DwarfCFI;
70}
71
72X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
73  : X86MCAsmInfoDarwin(Triple) {
74}
75
76void X86ELFMCAsmInfo::anchor() { }
77
78X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
79  if (T.getArch() == Triple::x86_64)
80    PointerSize = 8;
81
82  AssemblerDialect = AsmWriterFlavor;
83
84  TextAlignFillValue = 0x90;
85
86  PrivateGlobalPrefix = ".L";
87  WeakRefDirective = "\t.weak\t";
88  PCSymbol = ".";
89
90  // Set up DWARF directives
91  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
92
93  // Debug Information
94  SupportsDebugInformation = true;
95
96  // Exceptions handling
97  ExceptionsType = ExceptionHandling::DwarfCFI;
98
99  // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split
100  // into two .words.
101  if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) &&
102       T.getArch() == Triple::x86)
103    Data64bitsDirective = 0;
104}
105
106const MCExpr *
107X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
108                                                   unsigned Encoding,
109                                                   MCStreamer &Streamer) const {
110  MCContext &Context = Streamer.getContext();
111  const MCExpr *Res =
112    MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
113  const MCExpr *Four = MCConstantExpr::Create(4, Context);
114  return MCBinaryExpr::CreateAdd(Res, Four, Context);
115}
116
117const MCSection *X86ELFMCAsmInfo::
118getNonexecutableStackSection(MCContext &Ctx) const {
119  return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
120                           0, SectionKind::getMetadata());
121}
122
123void X86MCAsmInfoMicrosoft::anchor() { }
124
125X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
126  if (Triple.getArch() == Triple::x86_64) {
127    GlobalPrefix = "";
128    PrivateGlobalPrefix = ".L";
129  }
130
131  AssemblerDialect = AsmWriterFlavor;
132
133  TextAlignFillValue = 0x90;
134}
135
136void X86MCAsmInfoGNUCOFF::anchor() { }
137
138X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
139  if (Triple.getArch() == Triple::x86_64) {
140    GlobalPrefix = "";
141    PrivateGlobalPrefix = ".L";
142  }
143
144  AssemblerDialect = AsmWriterFlavor;
145
146  TextAlignFillValue = 0x90;
147
148  // Exceptions handling
149  ExceptionsType = ExceptionHandling::DwarfCFI;
150}
151