lib/Target/X86/X86AsmPrinter.cpp

   1 //===-- X86AsmPrinter.cpp - Convert X86 LLVM IR to X86 assembly -----------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file the shared super class printer that converts from our internal
  11 // representation of machine-dependent LLVM code to Intel and AT&T format
  12 // assembly language.
  13 // This printer is the output mechanism used by `llc'.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "X86ATTAsmPrinter.h"
  18 #include "X86IntelAsmPrinter.h"
  19 #include "X86.h"
  20 #include "llvm/Module.h"
  21 #include "llvm/Assembly/Writer.h"
  22 #include "llvm/CodeGen/MachineConstantPool.h"
  23 #include "llvm/Support/Mangler.h"
  24 #include "llvm/Support/CommandLine.h"
  25 using namespace llvm;
  26 using namespace x86;
  27
  28 Statistic<> llvm::x86::EmittedInsts("asm-printer",
  29                                     "Number of machine instrs printed");
  30
  31 enum AsmWriterFlavorTy { att, intel };
  32 cl::opt<AsmWriterFlavorTy>
  33 AsmWriterFlavor("x86-asm-syntax",
  34         cl::desc("Choose style of code to emit from X86 backend:"),
  35         cl::values(
  36                                 clEnumVal(att,   "  Emit AT&T-style assembly"),
  37                                 clEnumVal(intel, "  Emit Intel-style assembly"),
  38                                 clEnumValEnd),
  39         cl::init(att));
  40
  41 /// doInitialization
  42 bool X86SharedAsmPrinter::doInitialization(Module& M) {
  43   bool leadingUnderscore = false;
  44   forCygwin = false;
  45   const std::string& TT = M.getTargetTriple();
  46   if (TT.length() > 5) {
  47     forCygwin = TT.find("cygwin") != std::string::npos ||
  48                 TT.find("mingw")  != std::string::npos;
  49     forDarwin = TT.find("darwin") != std::string::npos;
  50   } else if (TT.empty()) {
  51   #if defined(__CYGWIN__) || defined(__MINGW32__)
  52     forCygwin = true;
  53   #elif defined(__APPLE__)
  54     forDarwin = true;
  55   #elif defined(_WIN32)
  56     leadingUnderscore = true;
  57   #else
  58     leadingUnderscore = false;
  59   #endif
  60   }
  61   if (leadingUnderscore || forCygwin || forDarwin)
  62     GlobalPrefix = "_";
  63
  64   if (forDarwin)
  65     AlignmentIsInBytes = false;
  66
  67   return AsmPrinter::doInitialization(M);
  68 }
  69
  70 /// printConstantPool - Print to the current output stream assembly
  71 /// representations of the constants in the constant pool MCP. This is
  72 /// used to print out constants which have been "spilled to memory" by
  73 /// the code generator.
  74 ///
  75 void X86SharedAsmPrinter::printConstantPool(MachineConstantPool *MCP) {
  76   const std::vector<Constant*> &CP = MCP->getConstants();
  77   const TargetData &TD = TM.getTargetData();
  78
  79   if (CP.empty()) return;
  80
  81   for (unsigned i = 0, e = CP.size(); i != e; ++i) {
  82     if (forDarwin)
  83       O << "\t.data\n";
  84     else
  85       O << "\t.section .rodata\n";
  86     emitAlignment(TD.getTypeAlignmentShift(CP[i]->getType()));
  87     O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t" << CommentString
  88       << *CP[i] << "\n";
  89     emitGlobalConstant(CP[i]);
  90   }
  91 }
  92
  93 bool X86SharedAsmPrinter::doFinalization(Module &M) {
  94   const TargetData &TD = TM.getTargetData();
  95   std::string CurSection;
  96
  97   // Print out module-level global variables here.
  98   for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
  99         if (I->hasInitializer()) {   // External global require no code
 100           O << "\n\n";
 101           std::string name = Mang->getValueName(I);
 102           Constant *C = I->getInitializer();
 103           unsigned Size = TD.getTypeSize(C->getType());
 104           unsigned Align = TD.getTypeAlignmentShift(C->getType());
 105
 106           if (C->isNullValue() &&
 107                 (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
 108                         I->hasWeakLinkage() /* FIXME: Verify correct */)) {
 109                 SwitchSection(O, CurSection, ".data");
 110                 if (!forCygwin && !forDarwin && I->hasInternalLinkage())
 111         O << "\t.local " << name << "\n";
 112       if (forDarwin && I->hasInternalLinkage())
 113          O << "\t.lcomm " << name << "," << Size << "," << Align;
 114       else
 115         O << "\t.comm " << name << "," << Size;
 116                 if (!forCygwin && !forDarwin)
 117                   O << "," << (1 << Align);
 118                 O << "\t\t# ";
 119                 WriteAsOperand(O, I, true, true, &M);
 120                 O << "\n";
 121           } else {
 122                 switch (I->getLinkage()) {
 123                 case GlobalValue::LinkOnceLinkage:
 124                 case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
 125                   // Nonnull linkonce -> weak
 126                   O << "\t.weak " << name << "\n";
 127                   SwitchSection(O, CurSection, "");
 128                   O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
 129                   break;
 130                 case GlobalValue::AppendingLinkage:
 131                   // FIXME: appending linkage variables should go into a section of
 132                   // their name or something.  For now, just emit them as external.
 133                 case GlobalValue::ExternalLinkage:
 134                   // If external or appending, declare as a global symbol
 135                   O << "\t.globl " << name << "\n";
 136                   // FALL THROUGH
 137                 case GlobalValue::InternalLinkage:
 138                   if (C->isNullValue())
 139                     SwitchSection(O, CurSection, ".bss");
 140                   else
 141                     SwitchSection(O, CurSection, ".data");
 142                   break;
 143                 case GlobalValue::GhostLinkage:
 144                   std::cerr << "GhostLinkage cannot appear in X86AsmPrinter!\n";
 145                   abort();
 146                 }
 147
 148                 emitAlignment(Align);
 149                 if (!forCygwin && !forDarwin) {
 150                   O << "\t.type " << name << ",@object\n";
 151                   O << "\t.size " << name << "," << Size << "\n";
 152                 }
 153                 O << name << ":\t\t\t\t# ";
 154                 WriteAsOperand(O, I, true, true, &M);
 155                 O << " = ";
 156                 WriteAsOperand(O, C, false, false, &M);
 157                 O << "\n";
 158                 emitGlobalConstant(C);
 159           }
 160     }
 161
 162   if (forDarwin) {
 163     // Output stubs for dynamically-linked functions
 164     unsigned j = 1;
 165     for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
 166          i != e; ++i, ++j)
 167     {
 168       O << "\t.symbol_stub\n";
 169       O << "L" << *i << "$stub:\n";
 170       O << "\t.indirect_symbol " << *i << "\n";
 171       O << "\tjmp\t*L" << j << "$lz\n";
 172       O << "L" << *i << "$stub_binder:\n";
 173       O << "\tpushl\t$L" << j << "$lz\n";
 174       O << "\tjmp\tdyld_stub_binding_helper\n";
 175       O << "\t.section __DATA, __la_sym_ptr3,lazy_symbol_pointers\n";
 176       O << "L" << j << "$lz:\n";
 177       O << "\t.indirect_symbol " << *i << "\n";
 178       O << "\t.long\tL" << *i << "$stub_binder\n";
 179     }
 180
 181     O << "\n";
 182
 183     // Output stubs for external global variables
 184     if (GVStubs.begin() != GVStubs.end())
 185       O << ".data\n.non_lazy_symbol_pointer\n";
 186     for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
 187          i != e; ++i) {
 188       O << "L" << *i << "$non_lazy_ptr:\n";
 189       O << "\t.indirect_symbol " << *i << "\n";
 190       O << "\t.long\t0\n";
 191     }
 192
 193     // Output stubs for link-once variables
 194     if (LinkOnceStubs.begin() != LinkOnceStubs.end())
 195       O << ".data\n.align 2\n";
 196     for (std::set<std::string>::iterator i = LinkOnceStubs.begin(),
 197          e = LinkOnceStubs.end(); i != e; ++i) {
 198       O << "L" << *i << "$non_lazy_ptr:\n"
 199         << "\t.long\t" << *i << '\n';
 200     }
 201   }
 202
 203   AsmPrinter::doFinalization(M);
 204   return false; // success
 205 }
 206
 207 /// createX86CodePrinterPass - Returns a pass that prints the X86 assembly code
 208 /// for a MachineFunction to the given output stream, using the given target
 209 /// machine description.
 210 ///
 211 FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,TargetMachine &tm){
 212   switch (AsmWriterFlavor) {
 213   default:
 214     assert(0 && "Unknown asm flavor!");
 215   case intel:
 216     return new X86IntelAsmPrinter(o, tm);
 217   case att:
 218     return new X86ATTAsmPrinter(o, tm);
 219   }
 220 }