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"
22 using namespace llvm;
23
24 enum 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
30 static cl::opt<AsmWriterFlavorTy>
31 AsmWriterFlavor("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 static cl::opt<bool>
38 MarkedJTDataRegions("mark-data-regions", cl::init(false),
39 cl::desc("Mark code section jump table data regions."),
40 cl::Hidden);
41
anchor()42 void X86MCAsmInfoDarwin::anchor() { }
43
X86MCAsmInfoDarwin(const Triple & T)44 X86MCAsmInfoDarwin::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
X86_64MCAsmInfoDarwin(const Triple & Triple)83 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
84 : X86MCAsmInfoDarwin(Triple) {
85 }
86
anchor()87 void X86ELFMCAsmInfo::anchor() { }
88
X86ELFMCAsmInfo(const Triple & T)89 X86ELFMCAsmInfo::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
116 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const117 X86_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
anchor()127 void X86MCAsmInfoMicrosoft::anchor() { }
128
X86MCAsmInfoMicrosoft(const Triple & Triple)129 X86MCAsmInfoMicrosoft::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
136 // Use MSVC-compatible EH data.
137 ExceptionsType = ExceptionHandling::MSVC;
138 }
139
140 AssemblerDialect = AsmWriterFlavor;
141
142 TextAlignFillValue = 0x90;
143
144 AllowAtInName = true;
145
146 UseIntegratedAssembler = true;
147 }
148
anchor()149 void X86MCAsmInfoGNUCOFF::anchor() { }
150
X86MCAsmInfoGNUCOFF(const Triple & Triple)151 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
152 assert(Triple.isOSWindows() && "Windows is the only supported COFF target");
153 if (Triple.getArch() == Triple::x86_64) {
154 PrivateGlobalPrefix = ".L";
155 PrivateLabelPrefix = ".L";
156 PointerSize = 8;
157 WinEHEncodingType = WinEH::EncodingType::Itanium;
158 ExceptionsType = ExceptionHandling::ItaniumWinEH;
159 } else {
160 ExceptionsType = ExceptionHandling::DwarfCFI;
161 }
162
163 AssemblerDialect = AsmWriterFlavor;
164
165 TextAlignFillValue = 0x90;
166
167 UseIntegratedAssembler = true;
168 }
169