X86MCAsmInfo.cpp revision 263508 
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 = CalleeSaveStackSlotSize = 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
63  SupportsDebugInformation = true;
64  UseDataRegionDirectives = MarkedJTDataRegions;
65
66  // Exceptions handling
67  ExceptionsType = ExceptionHandling::DwarfCFI;
68}
69
70X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
71  : X86MCAsmInfoDarwin(Triple) {
72}
73
74void X86ELFMCAsmInfo::anchor() { }
75
76X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
77  bool is64Bit = T.getArch() == Triple::x86_64;
78  bool isX32 = T.getEnvironment() == Triple::GNUX32;
79
80  // For ELF, x86-64 pointer size depends on the ABI.
81  // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64
82  // with the x32 ABI, pointer size remains the default 4.
83  PointerSize = (is64Bit && !isX32) ? 8 : 4;
84
85  // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI.
86  CalleeSaveStackSlotSize = is64Bit ? 8 : 4;
87
88  AssemblerDialect = AsmWriterFlavor;
89
90  TextAlignFillValue = 0x90;
91
92  PrivateGlobalPrefix = ".L";
93
94  // Set up DWARF directives
95  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
96
97  // Debug Information
98  SupportsDebugInformation = true;
99
100  // Exceptions handling
101  ExceptionsType = ExceptionHandling::DwarfCFI;
102
103  // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split
104  // into two .words.
105  if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) &&
106       T.getArch() == Triple::x86)
107    Data64bitsDirective = 0;
108}
109
110const MCExpr *
111X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
112                                                   unsigned Encoding,
113                                                   MCStreamer &Streamer) const {
114  MCContext &Context = Streamer.getContext();
115  const MCExpr *Res =
116    MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
117  const MCExpr *Four = MCConstantExpr::Create(4, Context);
118  return MCBinaryExpr::CreateAdd(Res, Four, Context);
119}
120
121const MCSection *X86ELFMCAsmInfo::
122getNonexecutableStackSection(MCContext &Ctx) const {
123  return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
124                           0, SectionKind::getMetadata());
125}
126
127void X86MCAsmInfoMicrosoft::anchor() { }
128
129X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
130  if (Triple.getArch() == Triple::x86_64) {
131    GlobalPrefix = "";
132    PrivateGlobalPrefix = ".L";
133  }
134
135  AssemblerDialect = AsmWriterFlavor;
136
137  TextAlignFillValue = 0x90;
138
139  AllowAtInName = true;
140}
141
142void X86MCAsmInfoGNUCOFF::anchor() { }
143
144X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
145  if (Triple.getArch() == Triple::x86_64) {
146    GlobalPrefix = "";
147    PrivateGlobalPrefix = ".L";
148  }
149
150  AssemblerDialect = AsmWriterFlavor;
151
152  TextAlignFillValue = 0x90;
153
154  // Exceptions handling
155  ExceptionsType = ExceptionHandling::DwarfCFI;
156}
157