lib/Target/X86/X86TargetAsmInfo.cpp

   1 //===-- X86TargetAsmInfo.cpp - X86 asm properties ---------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by James M. Laskey and is distributed under the
   6 // University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file contains the declarations of the X86TargetAsmInfo properties.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "X86TargetAsmInfo.h"
  15 #include "X86TargetMachine.h"
  16 #include "X86Subtarget.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/InlineAsm.h"
  19 #include "llvm/Instructions.h"
  20 #include "llvm/Intrinsics.h"
  21 #include "llvm/Module.h"
  22 #include "llvm/ADT/StringExtras.h"
  23 using namespace llvm;
  24
  25 static const char* x86_asm_table[] = {"{si}", "S",
  26                                       "{di}", "D",
  27                                       "{ax}", "a",
  28                                       "{cx}", "c",
  29                                       "{memory}", "memory",
  30                                       "{flags}", "",
  31                                       "{dirflag}", "",
  32                                       "{fpsr}", "",
  33                                       "{cc}", "cc",
  34                                       0,0};
  35
  36 X86TargetAsmInfo::X86TargetAsmInfo(const X86TargetMachine &TM) {
  37   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
  38
  39   // FIXME - Should be simplified.
  40
  41   AsmTransCBE = x86_asm_table;
  42
  43   switch (Subtarget->TargetType) {
  44   case X86Subtarget::isDarwin:
  45     AlignmentIsInBytes = false;
  46     GlobalPrefix = "_";
  47     if (!Subtarget->is64Bit())
  48       Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  49     ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  50     PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
  51     BSSSection = 0;                       // no BSS section.
  52     ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  53     ConstantPoolSection = "\t.const\n";
  54     JumpTableDataSection = "\t.const\n";
  55     CStringSection = "\t.cstring";
  56     FourByteConstantSection = "\t.literal4\n";
  57     EightByteConstantSection = "\t.literal8\n";
  58     if (Subtarget->is64Bit())
  59       SixteenByteConstantSection = "\t.literal16\n";
  60     ReadOnlySection = "\t.const\n";
  61     LCOMMDirective = "\t.lcomm\t";
  62     COMMDirectiveTakesAlignment = false;
  63     HasDotTypeDotSizeDirective = false;
  64     if (TM.getRelocationModel() == Reloc::Static) {
  65       StaticCtorsSection = ".constructor";
  66       StaticDtorsSection = ".destructor";
  67     } else {
  68       StaticCtorsSection = ".mod_init_func";
  69       StaticDtorsSection = ".mod_term_func";
  70     }
  71     InlineAsmStart = "# InlineAsm Start";
  72     InlineAsmEnd = "# InlineAsm End";
  73     SetDirective = "\t.set";
  74     PCSymbol = ".";
  75     UsedDirective = "\t.no_dead_strip\t";
  76     WeakRefDirective = "\t.weak_reference\t";
  77     HiddenDirective = "\t.private_extern\t";
  78
  79     // In non-PIC modes, emit a special label before jump tables so that the
  80     // linker can perform more accurate dead code stripping.
  81     if (TM.getRelocationModel() != Reloc::PIC_) {
  82       // Emit a local label that is preserved until the linker runs.
  83       JumpTableSpecialLabelPrefix = "l";
  84     }
  85
  86     SupportsDebugInformation = true;
  87     NeedsSet = true;
  88     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  89     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  90     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  91     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  92     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  93     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  94     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  95     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
  96     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
  97     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
  98     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
  99
 100     // Exceptions handling
 101     if (!Subtarget->is64Bit())
 102       SupportsExceptionHandling = true;
 103     AbsoluteEHSectionOffsets = false;
 104     DwarfEHFrameSection =
 105     ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 106     DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 107     break;
 108
 109   case X86Subtarget::isELF:
 110     ReadOnlySection = "\t.section\t.rodata";
 111     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 112     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 113     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 114     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 115     PrivateGlobalPrefix = ".L";
 116     WeakRefDirective = "\t.weak\t";
 117     SetDirective = "\t.set\t";
 118     PCSymbol = ".";
 119
 120     // Set up DWARF directives
 121     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 122
 123     // Debug Information
 124     AbsoluteDebugSectionOffsets = true;
 125     SupportsDebugInformation = true;
 126     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 127     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 128     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 129     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 130     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 131     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 132     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 133     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 134     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 135     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 136     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 137
 138     // Exceptions handling
 139     if (!Subtarget->is64Bit())
 140       SupportsExceptionHandling = true;
 141     AbsoluteEHSectionOffsets = false;
 142     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 143     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 144     break;
 145
 146   case X86Subtarget::isCygwin:
 147   case X86Subtarget::isMingw:
 148     GlobalPrefix = "_";
 149     LCOMMDirective = "\t.lcomm\t";
 150     COMMDirectiveTakesAlignment = false;
 151     HasDotTypeDotSizeDirective = false;
 152     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 153     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 154     HiddenDirective = NULL;
 155     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 156     WeakRefDirective = "\t.weak\t";
 157     SetDirective = "\t.set\t";
 158
 159     // Set up DWARF directives
 160     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 161     AbsoluteDebugSectionOffsets = true;
 162     AbsoluteEHSectionOffsets = false;
 163     SupportsDebugInformation = true;
 164     DwarfSectionOffsetDirective = "\t.secrel32\t";
 165     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 166     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 167     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 168     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 169     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 170     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 171     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 172     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 173     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 174     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 175     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 176     break;
 177
 178   case X86Subtarget::isWindows:
 179     GlobalPrefix = "_";
 180     HasDotTypeDotSizeDirective = false;
 181     break;
 182
 183   default: break;
 184   }
 185
 186   if (Subtarget->isFlavorIntel()) {
 187     GlobalPrefix = "_";
 188     CommentString = ";";
 189
 190     PrivateGlobalPrefix = "$";
 191     AlignDirective = "\talign\t";
 192     ZeroDirective = "\tdb\t";
 193     ZeroDirectiveSuffix = " dup(0)";
 194     AsciiDirective = "\tdb\t";
 195     AscizDirective = 0;
 196     Data8bitsDirective = "\tdb\t";
 197     Data16bitsDirective = "\tdw\t";
 198     Data32bitsDirective = "\tdd\t";
 199     Data64bitsDirective = "\tdq\t";
 200     HasDotTypeDotSizeDirective = false;
 201
 202     TextSection = "_text";
 203     DataSection = "_data";
 204     JumpTableDataSection = NULL;
 205     SwitchToSectionDirective = "";
 206     TextSectionStartSuffix = "\tsegment 'CODE'";
 207     DataSectionStartSuffix = "\tsegment 'DATA'";
 208     SectionEndDirectiveSuffix = "\tends\n";
 209   }
 210
 211   AssemblerDialect = Subtarget->getAsmFlavor();
 212 }
 213
 214 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 215   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 216   // we will turn this bswap into something that will be lowered to logical ops
 217   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 218   // so don't worry about this.
 219
 220   // Verify this is a simple bswap.
 221   if (CI->getNumOperands() != 2 ||
 222       CI->getType() != CI->getOperand(1)->getType() ||
 223       !CI->getType()->isInteger())
 224     return false;
 225
 226   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 227   if (!Ty || Ty->getBitWidth() % 16 != 0)
 228     return false;
 229
 230   // Okay, we can do this xform, do so now.
 231   const Type *Tys[] = { Ty };
 232   Module *M = CI->getParent()->getParent()->getParent();
 233   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 234
 235   Value *Op = CI->getOperand(1);
 236   Op = new CallInst(Int, Op, CI->getName(), CI);
 237
 238   CI->replaceAllUsesWith(Op);
 239   CI->eraseFromParent();
 240   return true;
 241 }
 242
 243
 244 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 245   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 246   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 247
 248   std::string AsmStr = IA->getAsmString();
 249
 250   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 251   std::vector<std::string> AsmPieces;
 252   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 253
 254   switch (AsmPieces.size()) {
 255   default: return false;
 256   case 1:
 257     AsmStr = AsmPieces[0];
 258     AsmPieces.clear();
 259     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 260
 261     // bswap $0
 262     if (AsmPieces.size() == 2 &&
 263         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 264       // No need to check constraints, nothing other than the equivalent of
 265       // "=r,0" would be valid here.
 266       return LowerToBSwap(CI);
 267     }
 268     break;
 269   case 3:
 270     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 271         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 272         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 273       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 274       std::vector<std::string> Words;
 275       SplitString(AsmPieces[0], Words, " \t");
 276       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 277         Words.clear();
 278         SplitString(AsmPieces[1], Words, " \t");
 279         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 280           Words.clear();
 281           SplitString(AsmPieces[2], Words, " \t,");
 282           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 283               Words[2] == "%edx") {
 284             return LowerToBSwap(CI);
 285           }
 286         }
 287       }
 288     }
 289     break;
 290   }
 291   return false;
 292 }