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(true),
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 = nullptr;       // 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  // old assembler lacks some directives
70  // FIXME: this should really be a check on the assembler characteristics
71  // rather than OS version
72  if (T.isMacOSX() && T.isMacOSXVersionLT(10, 6))
73    HasWeakDefCanBeHiddenDirective = false;
74
75  // Assume ld64 is new enough that the abs-ified FDE relocs may be used
76  // (actually, must, since otherwise the non-extern relocations we produce
77  // overwhelm ld64's tiny little mind and it fails).
78  DwarfFDESymbolsUseAbsDiff = true;
79
80  UseIntegratedAssembler = true;
81}
82
83X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
84  : X86MCAsmInfoDarwin(Triple) {
85}
86
87void X86ELFMCAsmInfo::anchor() { }
88
89X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
90  bool is64Bit = T.getArch() == Triple::x86_64;
91  bool isX32 = T.getEnvironment() == Triple::GNUX32;
92
93  // For ELF, x86-64 pointer size depends on the ABI.
94  // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64
95  // with the x32 ABI, pointer size remains the default 4.
96  PointerSize = (is64Bit && !isX32) ? 8 : 4;
97
98  // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI.
99  CalleeSaveStackSlotSize = is64Bit ? 8 : 4;
100
101  AssemblerDialect = AsmWriterFlavor;
102
103  TextAlignFillValue = 0x90;
104
105  // Debug Information
106  SupportsDebugInformation = true;
107
108  // Exceptions handling
109  ExceptionsType = ExceptionHandling::DwarfCFI;
110
111  // Always enable the integrated assembler by default.
112  // Clang also enabled it when the OS is Solaris but that is redundant here.
113  UseIntegratedAssembler = true;
114}
115
116const MCExpr *
117X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
118                                                   unsigned Encoding,
119                                                   MCStreamer &Streamer) const {
120  MCContext &Context = Streamer.getContext();
121  const MCExpr *Res =
122    MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
123  const MCExpr *Four = MCConstantExpr::create(4, Context);
124  return MCBinaryExpr::createAdd(Res, Four, Context);
125}
126
127void X86MCAsmInfoMicrosoft::anchor() { }
128
129X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
130  if (Triple.getArch() == Triple::x86_64) {
131    PrivateGlobalPrefix = ".L";
132    PrivateLabelPrefix = ".L";
133    PointerSize = 8;
134    WinEHEncodingType = WinEH::EncodingType::Itanium;
135  } else {
136    // 32-bit X86 doesn't use CFI, so this isn't a real encoding type. It's just
137    // a place holder that the Windows EHStreamer looks for to suppress CFI
138    // output. In particular, usesWindowsCFI() returns false.
139    WinEHEncodingType = WinEH::EncodingType::X86;
140  }
141
142  ExceptionsType = ExceptionHandling::WinEH;
143
144  AssemblerDialect = AsmWriterFlavor;
145
146  TextAlignFillValue = 0x90;
147
148  AllowAtInName = true;
149
150  UseIntegratedAssembler = true;
151}
152
153void X86MCAsmInfoGNUCOFF::anchor() { }
154
155X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
156  assert(Triple.isOSWindows() && "Windows is the only supported COFF target");
157  if (Triple.getArch() == Triple::x86_64) {
158    PrivateGlobalPrefix = ".L";
159    PrivateLabelPrefix = ".L";
160    PointerSize = 8;
161    WinEHEncodingType = WinEH::EncodingType::Itanium;
162    ExceptionsType = ExceptionHandling::WinEH;
163  } else {
164    ExceptionsType = ExceptionHandling::DwarfCFI;
165  }
166
167  AssemblerDialect = AsmWriterFlavor;
168
169  TextAlignFillValue = 0x90;
170
171  UseIntegratedAssembler = true;
172}
173