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     UsedDirective = "\t.no_dead_strip\t";
  75     WeakRefDirective = "\t.weak_reference\t";
  76     HiddenDirective = "\t.private_extern\t";
  77
  78     // In non-PIC modes, emit a special label before jump tables so that the
  79     // linker can perform more accurate dead code stripping.
  80     if (TM.getRelocationModel() != Reloc::PIC_) {
  81       // Emit a local label that is preserved until the linker runs.
  82       JumpTableSpecialLabelPrefix = "l";
  83     }
  84
  85     SupportsDebugInformation = true;
  86     NeedsSet = true;
  87     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  88     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  89     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  90     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  91     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  92     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  93     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  94     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
  95     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
  96     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
  97     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
  98     break;
  99
 100   case X86Subtarget::isELF:
 101     ReadOnlySection = "\t.section\t.rodata";
 102     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 103     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 104     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 105     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 106     PrivateGlobalPrefix = ".L";
 107     WeakRefDirective = "\t.weak\t";
 108     SetDirective = "\t.set\t";
 109     PCSymbol = ".";
 110
 111     // Set up DWARF directives
 112     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 113     AbsoluteDebugSectionOffsets = true;
 114     AbsoluteEHSectionOffsets = false;
 115     SupportsDebugInformation = true;
 116     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 117     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 118     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 119     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 120     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 121     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 122     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 123     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 124     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 125     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 126     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 127
 128     if (!Subtarget->is64Bit())
 129       SupportsExceptionHandling = true;
 130     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 131     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 132     break;
 133
 134   case X86Subtarget::isCygwin:
 135   case X86Subtarget::isMingw:
 136     GlobalPrefix = "_";
 137     LCOMMDirective = "\t.lcomm\t";
 138     COMMDirectiveTakesAlignment = false;
 139     HasDotTypeDotSizeDirective = false;
 140     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 141     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 142     HiddenDirective = NULL;
 143     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 144     WeakRefDirective = "\t.weak\t";
 145     SetDirective = "\t.set\t";
 146
 147     // Set up DWARF directives
 148     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 149     AbsoluteDebugSectionOffsets = true;
 150     AbsoluteEHSectionOffsets = false;
 151     SupportsDebugInformation = true;
 152     DwarfSectionOffsetDirective = "\t.secrel32\t";
 153     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 154     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 155     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 156     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 157     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 158     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 159     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 160     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 161     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 162     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 163     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 164     break;
 165
 166   case X86Subtarget::isWindows:
 167     GlobalPrefix = "_";
 168     HasDotTypeDotSizeDirective = false;
 169     break;
 170
 171   default: break;
 172   }
 173
 174   if (Subtarget->isFlavorIntel()) {
 175     GlobalPrefix = "_";
 176     CommentString = ";";
 177
 178     PrivateGlobalPrefix = "$";
 179     AlignDirective = "\talign\t";
 180     ZeroDirective = "\tdb\t";
 181     ZeroDirectiveSuffix = " dup(0)";
 182     AsciiDirective = "\tdb\t";
 183     AscizDirective = 0;
 184     Data8bitsDirective = "\tdb\t";
 185     Data16bitsDirective = "\tdw\t";
 186     Data32bitsDirective = "\tdd\t";
 187     Data64bitsDirective = "\tdq\t";
 188     HasDotTypeDotSizeDirective = false;
 189
 190     TextSection = "_text";
 191     DataSection = "_data";
 192     JumpTableDataSection = NULL;
 193     SwitchToSectionDirective = "";
 194     TextSectionStartSuffix = "\tsegment 'CODE'";
 195     DataSectionStartSuffix = "\tsegment 'DATA'";
 196     SectionEndDirectiveSuffix = "\tends\n";
 197   }
 198
 199   AssemblerDialect = Subtarget->getAsmFlavor();
 200 }
 201
 202 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 203   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 204   // we will turn this bswap into something that will be lowered to logical ops
 205   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 206   // so don't worry about this.
 207
 208   // Verify this is a simple bswap.
 209   if (CI->getNumOperands() != 2 ||
 210       CI->getType() != CI->getOperand(1)->getType() ||
 211       !CI->getType()->isInteger())
 212     return false;
 213
 214   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 215   if (!Ty || Ty->getBitWidth() % 16 != 0)
 216     return false;
 217
 218   // Okay, we can do this xform, do so now.
 219   const Type *Tys[] = { Ty, Ty };
 220   Module *M = CI->getParent()->getParent()->getParent();
 221   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 2);
 222
 223   Value *Op = CI->getOperand(1);
 224   Op = new CallInst(Int, Op, CI->getName(), CI);
 225
 226   CI->replaceAllUsesWith(Op);
 227   CI->eraseFromParent();
 228   return true;
 229 }
 230
 231
 232 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 233   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 234   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 235
 236   std::string AsmStr = IA->getAsmString();
 237
 238   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 239   std::vector<std::string> AsmPieces;
 240   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 241
 242   switch (AsmPieces.size()) {
 243   default: return false;
 244   case 1:
 245     AsmStr = AsmPieces[0];
 246     AsmPieces.clear();
 247     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 248
 249     // bswap $0
 250     if (AsmPieces.size() == 2 &&
 251         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 252       // No need to check constraints, nothing other than the equivalent of
 253       // "=r,0" would be valid here.
 254       return LowerToBSwap(CI);
 255     }
 256     break;
 257   case 3:
 258     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 259         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 260         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 261       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 262       std::vector<std::string> Words;
 263       SplitString(AsmPieces[0], Words, " \t");
 264       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 265         Words.clear();
 266         SplitString(AsmPieces[1], Words, " \t");
 267         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 268           Words.clear();
 269           SplitString(AsmPieces[2], Words, " \t,");
 270           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 271               Words[2] == "%edx") {
 272             return LowerToBSwap(CI);
 273           }
 274         }
 275       }
 276     }
 277     break;
 278   }
 279   return false;
 280 }