1 //===-- AArch64MCAsmInfo.cpp - AArch64 asm properties ---------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains the declarations of the AArch64MCAsmInfo properties.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "AArch64MCAsmInfo.h"
14 #include "llvm/ADT/Triple.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCStreamer.h"
18 #include "llvm/Support/CommandLine.h"
19 using namespace llvm;
20 
21 enum AsmWriterVariantTy {
22   Default = -1,
23   Generic = 0,
24   Apple = 1
25 };
26 
27 static cl::opt<AsmWriterVariantTy> AsmWriterVariant(
28     "aarch64-neon-syntax", cl::init(Default),
29     cl::desc("Choose style of NEON code to emit from AArch64 backend:"),
30     cl::values(clEnumValN(Generic, "generic", "Emit generic NEON assembly"),
31                clEnumValN(Apple, "apple", "Emit Apple-style NEON assembly")));
32 
33 AArch64MCAsmInfoDarwin::AArch64MCAsmInfoDarwin(bool IsILP32) {
34   // We prefer NEON instructions to be printed in the short, Apple-specific
35   // form when targeting Darwin.
36   AssemblerDialect = AsmWriterVariant == Default ? Apple : AsmWriterVariant;
37 
38   PrivateGlobalPrefix = "L";
39   PrivateLabelPrefix = "L";
40   SeparatorString = "%%";
41   CommentString = ";";
42   CalleeSaveStackSlotSize = 8;
43   CodePointerSize = IsILP32 ? 4 : 8;
44 
45   AlignmentIsInBytes = false;
46   UsesELFSectionDirectiveForBSS = true;
47   SupportsDebugInformation = true;
48   UseDataRegionDirectives = true;
49 
50   ExceptionsType = ExceptionHandling::DwarfCFI;
51 }
52 
53 const MCExpr *AArch64MCAsmInfoDarwin::getExprForPersonalitySymbol(
54     const MCSymbol *Sym, unsigned Encoding, MCStreamer &Streamer) const {
55   // On Darwin, we can reference dwarf symbols with foo@GOT-., which
56   // is an indirect pc-relative reference. The default implementation
57   // won't reference using the GOT, so we need this target-specific
58   // version.
59   MCContext &Context = Streamer.getContext();
60   const MCExpr *Res =
61       MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOT, Context);
62   MCSymbol *PCSym = Context.createTempSymbol();
63   Streamer.emitLabel(PCSym);
64   const MCExpr *PC = MCSymbolRefExpr::create(PCSym, Context);
65   return MCBinaryExpr::createSub(Res, PC, Context);
66 }
67 
68 AArch64MCAsmInfoELF::AArch64MCAsmInfoELF(const Triple &T) {
69   if (T.getArch() == Triple::aarch64_be)
70     IsLittleEndian = false;
71 
72   // We prefer NEON instructions to be printed in the generic form when
73   // targeting ELF.
74   AssemblerDialect = AsmWriterVariant == Default ? Generic : AsmWriterVariant;
75 
76   CodePointerSize = T.getEnvironment() == Triple::GNUILP32 ? 4 : 8;
77 
78   // ".comm align is in bytes but .align is pow-2."
79   AlignmentIsInBytes = false;
80 
81   CommentString = "//";
82   PrivateGlobalPrefix = ".L";
83   PrivateLabelPrefix = ".L";
84   Code32Directive = ".code\t32";
85 
86   Data16bitsDirective = "\t.hword\t";
87   Data32bitsDirective = "\t.word\t";
88   Data64bitsDirective = "\t.xword\t";
89 
90   UseDataRegionDirectives = false;
91 
92   WeakRefDirective = "\t.weak\t";
93 
94   SupportsDebugInformation = true;
95 
96   // Exceptions handling
97   ExceptionsType = ExceptionHandling::DwarfCFI;
98 
99   HasIdentDirective = true;
100 }
101 
102 AArch64MCAsmInfoMicrosoftCOFF::AArch64MCAsmInfoMicrosoftCOFF() {
103   PrivateGlobalPrefix = ".L";
104   PrivateLabelPrefix = ".L";
105 
106   Data16bitsDirective = "\t.hword\t";
107   Data32bitsDirective = "\t.word\t";
108   Data64bitsDirective = "\t.xword\t";
109 
110   AlignmentIsInBytes = false;
111   SupportsDebugInformation = true;
112   CodePointerSize = 8;
113 
114   CommentString = "//";
115   ExceptionsType = ExceptionHandling::WinEH;
116   WinEHEncodingType = WinEH::EncodingType::Itanium;
117 }
118 
119 AArch64MCAsmInfoGNUCOFF::AArch64MCAsmInfoGNUCOFF() {
120   PrivateGlobalPrefix = ".L";
121   PrivateLabelPrefix = ".L";
122 
123   Data16bitsDirective = "\t.hword\t";
124   Data32bitsDirective = "\t.word\t";
125   Data64bitsDirective = "\t.xword\t";
126 
127   AlignmentIsInBytes = false;
128   SupportsDebugInformation = true;
129   CodePointerSize = 8;
130 
131   CommentString = "//";
132   ExceptionsType = ExceptionHandling::WinEH;
133   WinEHEncodingType = WinEH::EncodingType::Itanium;
134 }
135