lib/Target/X86/X86TargetAsmInfo.cpp

   1 //===-- X86TargetAsmInfo.cpp - X86 asm properties ---------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // 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     WeakDefDirective = "\t.weak_definition ";
  80     WeakRefDirective = "\t.weak_reference ";
  81     HiddenDirective = "\t.private_extern\t";
  82
  83     // In non-PIC modes, emit a special label before jump tables so that the
  84     // linker can perform more accurate dead code stripping.
  85     if (TM.getRelocationModel() != Reloc::PIC_) {
  86       // Emit a local label that is preserved until the linker runs.
  87       JumpTableSpecialLabelPrefix = "l";
  88     }
  89
  90     SupportsDebugInformation = true;
  91     NeedsSet = true;
  92     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  93     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  94     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  95     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  96     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  97     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  98     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  99     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
 100     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
 101     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
 102     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
 103
 104     // Exceptions handling
 105     if (!Subtarget->is64Bit())
 106       SupportsExceptionHandling = true;
 107     GlobalEHDirective = "\t.globl\t";
 108     SupportsWeakOmittedEHFrame = false;
 109     AbsoluteEHSectionOffsets = false;
 110     DwarfEHFrameSection =
 111     ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
 112     DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
 113     break;
 114
 115   case X86Subtarget::isELF:
 116     ReadOnlySection = "\t.section\t.rodata";
 117     FourByteConstantSection = "\t.section\t.rodata.cst4,\"aM\",@progbits,4";
 118     EightByteConstantSection = "\t.section\t.rodata.cst8,\"aM\",@progbits,8";
 119     SixteenByteConstantSection = "\t.section\t.rodata.cst16,\"aM\",@progbits,16";
 120     CStringSection = "\t.section\t.rodata.str1.1,\"aMS\",@progbits,1";
 121     PrivateGlobalPrefix = ".L";
 122     WeakRefDirective = "\t.weak\t";
 123     SetDirective = "\t.set\t";
 124     PCSymbol = ".";
 125
 126     // Set up DWARF directives
 127     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 128
 129     // Debug Information
 130     AbsoluteDebugSectionOffsets = true;
 131     SupportsDebugInformation = true;
 132     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 133     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 134     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 135     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 136     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 137     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 138     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 139     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 140     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 141     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 142     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 143
 144     // Exceptions handling
 145     if (!Subtarget->is64Bit())
 146       SupportsExceptionHandling = true;
 147     AbsoluteEHSectionOffsets = false;
 148     DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
 149     DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";
 150     break;
 151
 152   case X86Subtarget::isCygwin:
 153   case X86Subtarget::isMingw:
 154     GlobalPrefix = "_";
 155     LCOMMDirective = "\t.lcomm\t";
 156     COMMDirectiveTakesAlignment = false;
 157     HasDotTypeDotSizeDirective = false;
 158     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 159     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 160     HiddenDirective = NULL;
 161     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 162     WeakRefDirective = "\t.weak\t";
 163     SetDirective = "\t.set\t";
 164
 165     // Set up DWARF directives
 166     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 167     AbsoluteDebugSectionOffsets = true;
 168     AbsoluteEHSectionOffsets = false;
 169     SupportsDebugInformation = true;
 170     DwarfSectionOffsetDirective = "\t.secrel32\t";
 171     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 172     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 173     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 174     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 175     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 176     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 177     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 178     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 179     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 180     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 181     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 182     break;
 183
 184   case X86Subtarget::isWindows:
 185     GlobalPrefix = "_";
 186     HasDotTypeDotSizeDirective = false;
 187     break;
 188
 189   default: break;
 190   }
 191
 192   if (Subtarget->isFlavorIntel()) {
 193     GlobalPrefix = "_";
 194     CommentString = ";";
 195
 196     PrivateGlobalPrefix = "$";
 197     AlignDirective = "\talign\t";
 198     ZeroDirective = "\tdb\t";
 199     ZeroDirectiveSuffix = " dup(0)";
 200     AsciiDirective = "\tdb\t";
 201     AscizDirective = 0;
 202     Data8bitsDirective = "\tdb\t";
 203     Data16bitsDirective = "\tdw\t";
 204     Data32bitsDirective = "\tdd\t";
 205     Data64bitsDirective = "\tdq\t";
 206     HasDotTypeDotSizeDirective = false;
 207
 208     TextSection = "_text";
 209     DataSection = "_data";
 210     JumpTableDataSection = NULL;
 211     SwitchToSectionDirective = "";
 212     TextSectionStartSuffix = "\tsegment 'CODE'";
 213     DataSectionStartSuffix = "\tsegment 'DATA'";
 214     SectionEndDirectiveSuffix = "\tends\n";
 215   }
 216
 217   AssemblerDialect = Subtarget->getAsmFlavor();
 218 }
 219
 220 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 221   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 222   // we will turn this bswap into something that will be lowered to logical ops
 223   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 224   // so don't worry about this.
 225
 226   // Verify this is a simple bswap.
 227   if (CI->getNumOperands() != 2 ||
 228       CI->getType() != CI->getOperand(1)->getType() ||
 229       !CI->getType()->isInteger())
 230     return false;
 231
 232   const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
 233   if (!Ty || Ty->getBitWidth() % 16 != 0)
 234     return false;
 235
 236   // Okay, we can do this xform, do so now.
 237   const Type *Tys[] = { Ty };
 238   Module *M = CI->getParent()->getParent()->getParent();
 239   Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);
 240
 241   Value *Op = CI->getOperand(1);
 242   Op = new CallInst(Int, Op, CI->getName(), CI);
 243
 244   CI->replaceAllUsesWith(Op);
 245   CI->eraseFromParent();
 246   return true;
 247 }
 248
 249
 250 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 251   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 252   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 253
 254   std::string AsmStr = IA->getAsmString();
 255
 256   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 257   std::vector<std::string> AsmPieces;
 258   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 259
 260   switch (AsmPieces.size()) {
 261   default: return false;
 262   case 1:
 263     AsmStr = AsmPieces[0];
 264     AsmPieces.clear();
 265     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 266
 267     // bswap $0
 268     if (AsmPieces.size() == 2 &&
 269         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 270       // No need to check constraints, nothing other than the equivalent of
 271       // "=r,0" would be valid here.
 272       return LowerToBSwap(CI);
 273     }
 274     break;
 275   case 3:
 276     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 277         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 278         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 279       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 280       std::vector<std::string> Words;
 281       SplitString(AsmPieces[0], Words, " \t");
 282       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 283         Words.clear();
 284         SplitString(AsmPieces[1], Words, " \t");
 285         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 286           Words.clear();
 287           SplitString(AsmPieces[2], Words, " \t,");
 288           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 289               Words[2] == "%edx") {
 290             return LowerToBSwap(CI);
 291           }
 292         }
 293       }
 294     }
 295     break;
 296   }
 297   return false;
 298 }