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
 114     // Debug Information
 115     AbsoluteDebugSectionOffsets = true;
 116     SupportsDebugInformation = true;
 117     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 118     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 119     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 120     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 121     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 122     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 123     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 124     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 125     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 126     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 127     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 128
 129     // Exceptions handling
 130     if (!Subtarget->is64Bit())
 131       SupportsExceptionHandling = true;
 132     AbsoluteEHSectionOffsets = false;
 133     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 134     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 135     break;
 136
 137   case X86Subtarget::isCygwin:
 138   case X86Subtarget::isMingw:
 139     GlobalPrefix = "_";
 140     LCOMMDirective = "\t.lcomm\t";
 141     COMMDirectiveTakesAlignment = false;
 142     HasDotTypeDotSizeDirective = false;
 143     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 144     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 145     HiddenDirective = NULL;
 146     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 147     WeakRefDirective = "\t.weak\t";
 148     SetDirective = "\t.set\t";
 149
 150     // Set up DWARF directives
 151     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 152     AbsoluteDebugSectionOffsets = true;
 153     AbsoluteEHSectionOffsets = false;
 154     SupportsDebugInformation = true;
 155     DwarfSectionOffsetDirective = "\t.secrel32\t";
 156     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 157     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 158     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 159     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 160     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 161     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 162     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 163     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 164     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 165     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 166     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 167     break;
 168
 169   case X86Subtarget::isWindows:
 170     GlobalPrefix = "_";
 171     HasDotTypeDotSizeDirective = false;
 172     break;
 173
 174   default: break;
 175   }
 176
 177   if (Subtarget->isFlavorIntel()) {
 178     GlobalPrefix = "_";
 179     CommentString = ";";
 180
 181     PrivateGlobalPrefix = "$";
 182     AlignDirective = "\talign\t";
 183     ZeroDirective = "\tdb\t";
 184     ZeroDirectiveSuffix = " dup(0)";
 185     AsciiDirective = "\tdb\t";
 186     AscizDirective = 0;
 187     Data8bitsDirective = "\tdb\t";
 188     Data16bitsDirective = "\tdw\t";
 189     Data32bitsDirective = "\tdd\t";
 190     Data64bitsDirective = "\tdq\t";
 191     HasDotTypeDotSizeDirective = false;
 192
 193     TextSection = "_text";
 194     DataSection = "_data";
 195     JumpTableDataSection = NULL;
 196     SwitchToSectionDirective = "";
 197     TextSectionStartSuffix = "\tsegment 'CODE'";
 198     DataSectionStartSuffix = "\tsegment 'DATA'";
 199     SectionEndDirectiveSuffix = "\tends\n";
 200   }
 201
 202   AssemblerDialect = Subtarget->getAsmFlavor();
 203 }
 204
 205 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 206   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 207   // we will turn this bswap into something that will be lowered to logical ops
 208   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 209   // so don't worry about this.
 210
 211   // Verify this is a simple bswap.
 212   if (CI->getNumOperands() != 2 ||
 213       CI->getType() != CI->getOperand(1)->getType() ||
 214       !CI->getType()->isInteger())
 215     return false;
 216
 217   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 218   if (!Ty || Ty->getBitWidth() % 16 != 0)
 219     return false;
 220
 221   // Okay, we can do this xform, do so now.
 222   const Type *Tys[] = { Ty };
 223   Module *M = CI->getParent()->getParent()->getParent();
 224   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 225
 226   Value *Op = CI->getOperand(1);
 227   Op = new CallInst(Int, Op, CI->getName(), CI);
 228
 229   CI->replaceAllUsesWith(Op);
 230   CI->eraseFromParent();
 231   return true;
 232 }
 233
 234
 235 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 236   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 237   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 238
 239   std::string AsmStr = IA->getAsmString();
 240
 241   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 242   std::vector<std::string> AsmPieces;
 243   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 244
 245   switch (AsmPieces.size()) {
 246   default: return false;
 247   case 1:
 248     AsmStr = AsmPieces[0];
 249     AsmPieces.clear();
 250     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 251
 252     // bswap $0
 253     if (AsmPieces.size() == 2 &&
 254         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 255       // No need to check constraints, nothing other than the equivalent of
 256       // "=r,0" would be valid here.
 257       return LowerToBSwap(CI);
 258     }
 259     break;
 260   case 3:
 261     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 262         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 263         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 264       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 265       std::vector<std::string> Words;
 266       SplitString(AsmPieces[0], Words, " \t");
 267       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 268         Words.clear();
 269         SplitString(AsmPieces[1], Words, " \t");
 270         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 271           Words.clear();
 272           SplitString(AsmPieces[2], Words, " \t,");
 273           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 274               Words[2] == "%edx") {
 275             return LowerToBSwap(CI);
 276           }
 277         }
 278       }
 279     }
 280     break;
 281   }
 282   return false;
 283 }