X86MCAsmInfo.cpp revision 847307a35b33bf3b9c68510c71b41794de9f2cca 
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
37
38static const char *const x86_asm_table[] = {
39  "{si}", "S",
40  "{di}", "D",
41  "{ax}", "a",
42  "{cx}", "c",
43  "{memory}", "memory",
44  "{flags}", "",
45  "{dirflag}", "",
46  "{fpsr}", "",
47  "{fpcr}", "",
48  "{cc}", "cc",
49  0,0};
50
51void X86MCAsmInfoDarwin::anchor() { }
52
53X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
54  bool is64Bit = T.getArch() == Triple::x86_64;
55  if (is64Bit)
56    PointerSize = 8;
57
58  AsmTransCBE = x86_asm_table;
59  AssemblerDialect = AsmWriterFlavor;
60
61  TextAlignFillValue = 0x90;
62
63  if (!is64Bit)
64    Data64bitsDirective = 0;       // we can't emit a 64-bit unit
65
66  // Use ## as a comment string so that .s files generated by llvm can go
67  // through the GCC preprocessor without causing an error.  This is needed
68  // because "clang foo.s" runs the C preprocessor, which is usually reserved
69  // for .S files on other systems.  Perhaps this is because the file system
70  // wasn't always case preserving or something.
71  CommentString = "##";
72  PCSymbol = ".";
73
74  SupportsDebugInformation = true;
75  DwarfUsesInlineInfoSection = true;
76
77  // Exceptions handling
78  ExceptionsType = ExceptionHandling::DwarfCFI;
79}
80
81X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
82  : X86MCAsmInfoDarwin(Triple) {
83}
84
85void X86ELFMCAsmInfo::anchor() { }
86
87X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
88  if (T.getArch() == Triple::x86_64)
89    PointerSize = 8;
90
91  AsmTransCBE = x86_asm_table;
92  AssemblerDialect = AsmWriterFlavor;
93
94  TextAlignFillValue = 0x90;
95
96  PrivateGlobalPrefix = ".L";
97  WeakRefDirective = "\t.weak\t";
98  PCSymbol = ".";
99
100  // Set up DWARF directives
101  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
102
103  // Debug Information
104  SupportsDebugInformation = true;
105
106  // Exceptions handling
107  ExceptionsType = ExceptionHandling::DwarfCFI;
108
109  // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
110  // .words.
111  if (T.getOS() == Triple::OpenBSD && T.getArch() == Triple::x86)
112    Data64bitsDirective = 0;
113}
114
115const MCExpr *
116X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
117                                                   unsigned Encoding,
118                                                   MCStreamer &Streamer) const {
119  MCContext &Context = Streamer.getContext();
120  const MCExpr *Res =
121    MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
122  const MCExpr *Four = MCConstantExpr::Create(4, Context);
123  return MCBinaryExpr::CreateAdd(Res, Four, Context);
124}
125
126const MCSection *X86ELFMCAsmInfo::
127getNonexecutableStackSection(MCContext &Ctx) const {
128  return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
129                           0, SectionKind::getMetadata());
130}
131
132void X86MCAsmInfoMicrosoft::anchor() { }
133
134X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
135  if (Triple.getArch() == Triple::x86_64) {
136    GlobalPrefix = "";
137    PrivateGlobalPrefix = ".L";
138  }
139
140  AsmTransCBE = x86_asm_table;
141  AssemblerDialect = AsmWriterFlavor;
142
143  TextAlignFillValue = 0x90;
144}
145
146void X86MCAsmInfoGNUCOFF::anchor() { }
147
148X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
149  if (Triple.getArch() == Triple::x86_64) {
150    GlobalPrefix = "";
151    PrivateGlobalPrefix = ".L";
152  }
153
154  AsmTransCBE = x86_asm_table;
155  AssemblerDialect = AsmWriterFlavor;
156
157  TextAlignFillValue = 0x90;
158
159  // Exceptions handling
160  ExceptionsType = ExceptionHandling::DwarfCFI;
161}
162