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     PersonalityPrefix = "L";
  72     PersonalitySuffix = "$non_lazy_ptr";
  73     NeedsIndirectEncoding = true;
  74     InlineAsmStart = "# InlineAsm Start";
  75     InlineAsmEnd = "# InlineAsm End";
  76     SetDirective = "\t.set";
  77     PCSymbol = ".";
  78     UsedDirective = "\t.no_dead_strip\t";
  79     WeakRefDirective = "\t.weak_reference\t";
  80     HiddenDirective = "\t.private_extern\t";
  81
  82     // In non-PIC modes, emit a special label before jump tables so that the
  83     // linker can perform more accurate dead code stripping.
  84     if (TM.getRelocationModel() != Reloc::PIC_) {
  85       // Emit a local label that is preserved until the linker runs.
  86       JumpTableSpecialLabelPrefix = "l";
  87     }
  88
  89     SupportsDebugInformation = true;
  90     NeedsSet = true;
  91     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  92     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  93     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  94     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  95     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  96     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  97     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  98     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
  99     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 100     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 101     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 102
 103     // Exceptions handling
 104     SupportsExceptionHandling = true;
 105     AbsoluteEHSectionOffsets = false;
 106     DwarfEHFrameSection =
 107     ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 108     DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 109     break;
 110
 111   case X86Subtarget::isELF:
 112     ReadOnlySection = "\t.section\t.rodata";
 113     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 114     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 115     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 116     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 117     PrivateGlobalPrefix = ".L";
 118     WeakRefDirective = "\t.weak\t";
 119     SetDirective = "\t.set\t";
 120     PCSymbol = ".";
 121
 122     // Set up DWARF directives
 123     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 124
 125     // Debug Information
 126     AbsoluteDebugSectionOffsets = true;
 127     SupportsDebugInformation = true;
 128     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 129     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 130     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 131     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 132     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 133     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 134     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 135     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 136     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 137     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 138     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 139
 140     // Exceptions handling
 141     if (!Subtarget->is64Bit())
 142       SupportsExceptionHandling = true;
 143     AbsoluteEHSectionOffsets = false;
 144     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 145     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 146     break;
 147
 148   case X86Subtarget::isCygwin:
 149   case X86Subtarget::isMingw:
 150     GlobalPrefix = "_";
 151     LCOMMDirective = "\t.lcomm\t";
 152     COMMDirectiveTakesAlignment = false;
 153     HasDotTypeDotSizeDirective = false;
 154     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 155     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 156     HiddenDirective = NULL;
 157     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 158     WeakRefDirective = "\t.weak\t";
 159     SetDirective = "\t.set\t";
 160
 161     // Set up DWARF directives
 162     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 163     AbsoluteDebugSectionOffsets = true;
 164     AbsoluteEHSectionOffsets = false;
 165     SupportsDebugInformation = true;
 166     DwarfSectionOffsetDirective = "\t.secrel32\t";
 167     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 168     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 169     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 170     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 171     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 172     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 173     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 174     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 175     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 176     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 177     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 178     break;
 179
 180   case X86Subtarget::isWindows:
 181     GlobalPrefix = "_";
 182     HasDotTypeDotSizeDirective = false;
 183     break;
 184
 185   default: break;
 186   }
 187
 188   if (Subtarget->isFlavorIntel()) {
 189     GlobalPrefix = "_";
 190     CommentString = ";";
 191
 192     PrivateGlobalPrefix = "$";
 193     AlignDirective = "\talign\t";
 194     ZeroDirective = "\tdb\t";
 195     ZeroDirectiveSuffix = " dup(0)";
 196     AsciiDirective = "\tdb\t";
 197     AscizDirective = 0;
 198     Data8bitsDirective = "\tdb\t";
 199     Data16bitsDirective = "\tdw\t";
 200     Data32bitsDirective = "\tdd\t";
 201     Data64bitsDirective = "\tdq\t";
 202     HasDotTypeDotSizeDirective = false;
 203
 204     TextSection = "_text";
 205     DataSection = "_data";
 206     JumpTableDataSection = NULL;
 207     SwitchToSectionDirective = "";
 208     TextSectionStartSuffix = "\tsegment 'CODE'";
 209     DataSectionStartSuffix = "\tsegment 'DATA'";
 210     SectionEndDirectiveSuffix = "\tends\n";
 211   }
 212
 213   AssemblerDialect = Subtarget->getAsmFlavor();
 214 }
 215
 216 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 217   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 218   // we will turn this bswap into something that will be lowered to logical ops
 219   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 220   // so don't worry about this.
 221
 222   // Verify this is a simple bswap.
 223   if (CI->getNumOperands() != 2 ||
 224       CI->getType() != CI->getOperand(1)->getType() ||
 225       !CI->getType()->isInteger())
 226     return false;
 227
 228   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 229   if (!Ty || Ty->getBitWidth() % 16 != 0)
 230     return false;
 231
 232   // Okay, we can do this xform, do so now.
 233   const Type *Tys[] = { Ty };
 234   Module *M = CI->getParent()->getParent()->getParent();
 235   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 236
 237   Value *Op = CI->getOperand(1);
 238   Op = new CallInst(Int, Op, CI->getName(), CI);
 239
 240   CI->replaceAllUsesWith(Op);
 241   CI->eraseFromParent();
 242   return true;
 243 }
 244
 245
 246 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 247   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 248   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 249
 250   std::string AsmStr = IA->getAsmString();
 251
 252   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 253   std::vector<std::string> AsmPieces;
 254   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 255
 256   switch (AsmPieces.size()) {
 257   default: return false;
 258   case 1:
 259     AsmStr = AsmPieces[0];
 260     AsmPieces.clear();
 261     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 262
 263     // bswap $0
 264     if (AsmPieces.size() == 2 &&
 265         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 266       // No need to check constraints, nothing other than the equivalent of
 267       // "=r,0" would be valid here.
 268       return LowerToBSwap(CI);
 269     }
 270     break;
 271   case 3:
 272     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 273         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 274         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 275       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 276       std::vector<std::string> Words;
 277       SplitString(AsmPieces[0], Words, " \t");
 278       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 279         Words.clear();
 280         SplitString(AsmPieces[1], Words, " \t");
 281         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 282           Words.clear();
 283           SplitString(AsmPieces[2], Words, " \t,");
 284           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 285               Words[2] == "%edx") {
 286             return LowerToBSwap(CI);
 287           }
 288         }
 289       }
 290     }
 291     break;
 292   }
 293   return false;
 294 }