1 //===-- X86MCAsmInfo.cpp - X86 asm properties -----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the declarations of the X86MCAsmInfo properties.
12 //===----------------------------------------------------------------------===//
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"
24 enum AsmWriterFlavorTy {
25 // Note: This numbering has to match the GCC assembler dialects for inline
26 // asm alternatives to work right.
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"),
38 MarkedJTDataRegions("mark-data-regions", cl::init(false),
39 cl::desc("Mark code section jump table data regions."),
42 void X86MCAsmInfoDarwin::anchor() { }
44 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
45 bool is64Bit = T.getArch() == Triple::x86_64;
47 PointerSize = CalleeSaveStackSlotSize = 8;
49 AssemblerDialect = AsmWriterFlavor;
51 TextAlignFillValue = 0x90;
54 Data64bitsDirective = nullptr; // we can't emit a 64-bit unit
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.
63 SupportsDebugInformation = true;
64 UseDataRegionDirectives = MarkedJTDataRegions;
66 // Exceptions handling
67 ExceptionsType = ExceptionHandling::DwarfCFI;
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;
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;
80 UseIntegratedAssembler = true;
83 X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
84 : X86MCAsmInfoDarwin(Triple) {
87 void X86ELFMCAsmInfo::anchor() { }
89 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
90 bool is64Bit = T.getArch() == Triple::x86_64;
91 bool isX32 = T.getEnvironment() == Triple::GNUX32;
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;
98 // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI.
99 CalleeSaveStackSlotSize = is64Bit ? 8 : 4;
101 AssemblerDialect = AsmWriterFlavor;
103 TextAlignFillValue = 0x90;
106 SupportsDebugInformation = true;
108 // Exceptions handling
109 ExceptionsType = ExceptionHandling::DwarfCFI;
111 // OpenBSD and Bitrig have buggy support for .quad in 32-bit mode, just split
113 if ((T.getOS() == Triple::OpenBSD || T.getOS() == Triple::Bitrig) &&
114 T.getArch() == Triple::x86)
115 Data64bitsDirective = nullptr;
117 // Always enable the integrated assembler by default.
118 // Clang also enabled it when the OS is Solaris but that is redundant here.
119 UseIntegratedAssembler = true;
123 X86_64MCAsmInfoDarwin::getExprForPersonalitySymbol(const MCSymbol *Sym,
125 MCStreamer &Streamer) const {
126 MCContext &Context = Streamer.getContext();
128 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Context);
129 const MCExpr *Four = MCConstantExpr::Create(4, Context);
130 return MCBinaryExpr::CreateAdd(Res, Four, Context);
133 const MCSection *X86ELFMCAsmInfo::
134 getNonexecutableStackSection(MCContext &Ctx) const {
135 return Ctx.getELFSection(".note.GNU-stack", ELF::SHT_PROGBITS,
136 0, SectionKind::getMetadata());
139 void X86MCAsmInfoMicrosoft::anchor() { }
141 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
142 if (Triple.getArch() == Triple::x86_64) {
143 PrivateGlobalPrefix = ".L";
145 ExceptionsType = ExceptionHandling::WinEH;
148 AssemblerDialect = AsmWriterFlavor;
150 TextAlignFillValue = 0x90;
152 AllowAtInName = true;
154 UseIntegratedAssembler = true;
157 void X86MCAsmInfoGNUCOFF::anchor() { }
159 X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
160 assert(Triple.isOSWindows() && "Windows is the only supported COFF target");
161 if (Triple.getArch() == Triple::x86_64) {
162 PrivateGlobalPrefix = ".L";
164 ExceptionsType = ExceptionHandling::WinEH;
166 ExceptionsType = ExceptionHandling::DwarfCFI;
169 AssemblerDialect = AsmWriterFlavor;
171 TextAlignFillValue = 0x90;
173 UseIntegratedAssembler = true;