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