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/Module.h"
  21 #include "llvm/ADT/StringExtras.h"
  22 using namespace llvm;
  23
  24 static const char* x86_asm_table[] = {"{si}", "S",
  25                                       "{di}", "D",
  26                                       "{ax}", "a",
  27                                       "{cx}", "c",
  28                                       "{memory}", "memory",
  29                                       "{flags}", "",
  30                                       "{dirflag}", "",
  31                                       "{fpsr}", "",
  32                                       "{cc}", "cc",
  33                                       0,0};
  34
  35 X86TargetAsmInfo::X86TargetAsmInfo(const X86TargetMachine &TM) {
  36   const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
  37
  38   // FIXME - Should be simplified.
  39
  40   AsmTransCBE = x86_asm_table;
  41
  42   switch (Subtarget->TargetType) {
  43   case X86Subtarget::isDarwin:
  44     AlignmentIsInBytes = false;
  45     GlobalPrefix = "_";
  46     if (!Subtarget->is64Bit())
  47       Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  48     ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  49     PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
  50     BSSSection = 0;                       // no BSS section.
  51     ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  52     ConstantPoolSection = "\t.const\n";
  53     JumpTableDataSection = "\t.const\n";
  54     CStringSection = "\t.cstring";
  55     FourByteConstantSection = "\t.literal4\n";
  56     EightByteConstantSection = "\t.literal8\n";
  57     if (Subtarget->is64Bit())
  58       SixteenByteConstantSection = "\t.literal16\n";
  59     ReadOnlySection = "\t.const\n";
  60     LCOMMDirective = "\t.lcomm\t";
  61     COMMDirectiveTakesAlignment = false;
  62     HasDotTypeDotSizeDirective = false;
  63     if (TM.getRelocationModel() == Reloc::Static) {
  64       StaticCtorsSection = ".constructor";
  65       StaticDtorsSection = ".destructor";
  66     } else {
  67       StaticCtorsSection = ".mod_init_func";
  68       StaticDtorsSection = ".mod_term_func";
  69     }
  70     InlineAsmStart = "# InlineAsm Start";
  71     InlineAsmEnd = "# InlineAsm End";
  72     SetDirective = "\t.set";
  73     UsedDirective = "\t.no_dead_strip\t";
  74     WeakRefDirective = "\t.weak_reference\t";
  75     HiddenDirective = "\t.private_extern\t";
  76
  77     // In non-PIC modes, emit a special label before jump tables so that the
  78     // linker can perform more accurate dead code stripping.
  79     if (TM.getRelocationModel() != Reloc::PIC_) {
  80       // Emit a local label that is preserved until the linker runs.
  81       JumpTableSpecialLabelPrefix = "l";
  82     }
  83
  84     NeedsSet = true;
  85     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  86     DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  87     DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  88     DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  89     DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  90     DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  91     DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  92     DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
  93     DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
  94     DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
  95     DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";
  96     break;
  97
  98   case X86Subtarget::isELF:
  99     // Set up DWARF directives
 100     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 101     AbsoluteSectionOffsets = true;
 102     // bool HasLEB128; // Defaults to false.
 103     // hasDotLoc - True if target asm supports .loc directives.
 104     // bool HasDotLoc; // Defaults to false.
 105     // HasDotFile - True if target asm supports .file directives.
 106     // bool HasDotFile; // Defaults to false.
 107     ReadOnlySection = "\t.section\t.rodata\n";
 108     PrivateGlobalPrefix = ".L";
 109     WeakRefDirective = "\t.weak\t";
 110     DwarfRequiresFrameSection = false;
 111     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
 112     DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
 113     DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
 114     DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
 115     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
 116     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
 117     DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
 118     DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
 119     DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
 120     DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
 121     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";
 122     break;
 123
 124   case X86Subtarget::isCygwin:
 125   case X86Subtarget::isMingw:
 126     GlobalPrefix = "_";
 127     LCOMMDirective = "\t.lcomm\t";
 128     COMMDirectiveTakesAlignment = false;
 129     HasDotTypeDotSizeDirective = false;
 130     StaticCtorsSection = "\t.section .ctors,\"aw\"";
 131     StaticDtorsSection = "\t.section .dtors,\"aw\"";
 132     HiddenDirective = NULL;
 133
 134     // Set up DWARF directives
 135     HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
 136     AbsoluteSectionOffsets = true;
 137     PrivateGlobalPrefix = "L";  // Prefix for private global symbols
 138     WeakRefDirective = "\t.weak\t";
 139     DwarfRequiresFrameSection = false;
 140     DwarfSectionOffsetDirective = "\t.secrel32\t";
 141     DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
 142     DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
 143     DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
 144     DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
 145     DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
 146     DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
 147     DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
 148     DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
 149     DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
 150     DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
 151     DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
 152     break;
 153
 154   case X86Subtarget::isWindows:
 155     GlobalPrefix = "_";
 156     HasDotTypeDotSizeDirective = false;
 157     break;
 158
 159   default: break;
 160   }
 161
 162   if (Subtarget->isFlavorIntel()) {
 163     GlobalPrefix = "_";
 164     CommentString = ";";
 165
 166     PrivateGlobalPrefix = "$";
 167     AlignDirective = "\talign\t";
 168     ZeroDirective = "\tdb\t";
 169     ZeroDirectiveSuffix = " dup(0)";
 170     AsciiDirective = "\tdb\t";
 171     AscizDirective = 0;
 172     Data8bitsDirective = "\tdb\t";
 173     Data16bitsDirective = "\tdw\t";
 174     Data32bitsDirective = "\tdd\t";
 175     Data64bitsDirective = "\tdq\t";
 176     HasDotTypeDotSizeDirective = false;
 177
 178     TextSection = "_text";
 179     DataSection = "_data";
 180     JumpTableDataSection = NULL;
 181     SwitchToSectionDirective = "";
 182     TextSectionStartSuffix = "\tsegment 'CODE'";
 183     DataSectionStartSuffix = "\tsegment 'DATA'";
 184     SectionEndDirectiveSuffix = "\tends\n";
 185   }
 186
 187   AssemblerDialect = Subtarget->getAsmFlavor();
 188 }
 189
 190 bool X86TargetAsmInfo::LowerToBSwap(CallInst *CI) const {
 191   // FIXME: this should verify that we are targetting a 486 or better.  If not,
 192   // we will turn this bswap into something that will be lowered to logical ops
 193   // instead of emitting the bswap asm.  For now, we don't support 486 or lower
 194   // so don't worry about this.
 195
 196   // Verify this is a simple bswap.
 197   if (CI->getNumOperands() != 2 ||
 198       CI->getType() != CI->getOperand(1)->getType() ||
 199       !CI->getType()->isInteger())
 200     return false;
 201
 202   const Type *Ty = CI->getType();
 203   const char *IntName;
 204   if (const IntegerType *ITy = dyn_cast<IntegerType>(Ty)) {
 205     unsigned BitWidth = ITy->getBitWidth();
 206     if (BitWidth == 16)
 207       IntName = "llvm.bswap.i16";
 208     else if (BitWidth == 32)
 209       IntName = "llvm.bswap.i32";
 210     else if (BitWidth == 64)
 211       IntName = "llvm.bswap.i64";
 212     else
 213       return false;
 214   } else
 215     return false;
 216
 217   // Okay, we can do this xform, do so now.
 218   Module *M = CI->getParent()->getParent()->getParent();
 219   Constant *Int = M->getOrInsertFunction(IntName, Ty, Ty, (Type*)0);
 220
 221   Value *Op = CI->getOperand(1);
 222   Op = new CallInst(Int, Op, CI->getName(), CI);
 223
 224   CI->replaceAllUsesWith(Op);
 225   CI->eraseFromParent();
 226   return true;
 227 }
 228
 229
 230 bool X86TargetAsmInfo::ExpandInlineAsm(CallInst *CI) const {
 231   InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
 232   std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
 233
 234   std::string AsmStr = IA->getAsmString();
 235
 236   // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
 237   std::vector<std::string> AsmPieces;
 238   SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?
 239
 240   switch (AsmPieces.size()) {
 241   default: return false;
 242   case 1:
 243     AsmStr = AsmPieces[0];
 244     AsmPieces.clear();
 245     SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.
 246
 247     // bswap $0
 248     if (AsmPieces.size() == 2 &&
 249         AsmPieces[0] == "bswap" && AsmPieces[1] == "$0") {
 250       // No need to check constraints, nothing other than the equivalent of
 251       // "=r,0" would be valid here.
 252       return LowerToBSwap(CI);
 253     }
 254     break;
 255   case 3:
 256     if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
 257         Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
 258         Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
 259       // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
 260       std::vector<std::string> Words;
 261       SplitString(AsmPieces[0], Words, " \t");
 262       if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
 263         Words.clear();
 264         SplitString(AsmPieces[1], Words, " \t");
 265         if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
 266           Words.clear();
 267           SplitString(AsmPieces[2], Words, " \t,");
 268           if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
 269               Words[2] == "%edx") {
 270             return LowerToBSwap(CI);
 271           }
 272         }
 273       }
 274     }
 275     break;
 276   }
 277   return false;
 278 }