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
38 static 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
X86MCAsmInfoDarwin(const Triple & T)51 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
52 bool is64Bit = T.getArch() == Triple::x86_64;
53 if (is64Bit)
54 PointerSize = 8;
55
56 AsmTransCBE = x86_asm_table;
57 AssemblerDialect = AsmWriterFlavor;
58
59 TextAlignFillValue = 0x90;
60
61 if (!is64Bit)
62 Data64bitsDirective = 0; // we can't emit a 64-bit unit
63
64 // Use ## as a comment string so that .s files generated by llvm can go
65 // through the GCC preprocessor without causing an error. This is needed
66 // because "clang foo.s" runs the C preprocessor, which is usually reserved
67 // for .S files on other systems. Perhaps this is because the file system
68 // wasn't always case preserving or something.
69 CommentString = "##";
70 PCSymbol = ".";
71
72 SupportsDebugInformation = true;
73 DwarfUsesInlineInfoSection = true;
74
75 // Exceptions handling
76 ExceptionsType = ExceptionHandling::DwarfCFI;
77 }
78
X86_64MCAsmInfoDarwin(const Triple & Triple)79 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
80 : X86MCAsmInfoDarwin(Triple) {
81 }
82
X86ELFMCAsmInfo(const Triple & T)83 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
84 if (T.getArch() == Triple::x86_64)
85 PointerSize = 8;
86
87 AsmTransCBE = x86_asm_table;
88 AssemblerDialect = AsmWriterFlavor;
89
90 TextAlignFillValue = 0x90;
91
92 PrivateGlobalPrefix = ".L";
93 WeakRefDirective = "\t.weak\t";
94 PCSymbol = ".";
95
96 // Set up DWARF directives
97 HasLEB128 = true; // Target asm supports leb128 directives (little-endian)
98
99 // Debug Information
100 SupportsDebugInformation = true;
101
102 // Exceptions handling
103 ExceptionsType = ExceptionHandling::DwarfCFI;
104
105 // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
106 // .words.
107 if (T.getOS() == Triple::OpenBSD && T.getArch() == Triple::x86)
108 Data64bitsDirective = 0;
109 }
110
111 const MCExpr *
getExprForPersonalitySymbol(const MCSymbol * Sym,unsigned Encoding,MCStreamer & Streamer) const112 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
113 unsigned Encoding,
114 MCStreamer &Streamer) const {
115 MCContext &Context = Streamer.getContext();
116 const MCExpr *Res =
117 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
118 const MCExpr *Four = MCConstantExpr::Create(4, Context);
119 return MCBinaryExpr::CreateAdd(Res, Four, Context);
120 }
121
122 const MCSection *X86ELFMCAsmInfo::
getNonexecutableStackSection(MCContext & Ctx) const123 getNonexecutableStackSection(MCContext &Ctx) const {
124 return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
125 0, SectionKind::getMetadata());
126 }
127
X86MCAsmInfoCOFF(const Triple & Triple)128 X86MCAsmInfoCOFF::X86MCAsmInfoCOFF(const Triple &Triple) {
129 if (Triple.getArch() == Triple::x86_64) {
130 GlobalPrefix = "";
131 PrivateGlobalPrefix = ".L";
132 }
133
134 AsmTransCBE = x86_asm_table;
135 AssemblerDialect = AsmWriterFlavor;
136
137 TextAlignFillValue = 0x90;
138 }
139