It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86IntelAsmPrinter.cpp b/lib/Target/X86/X86IntelAsmPrinter.cpp
new file mode 100755
index 0000000..39b65ee
--- /dev/null
+++ b/lib/Target/X86/X86IntelAsmPrinter.cpp
@@ -0,0 +1,533 @@
+//===-- X86IntelAsmPrinter.cpp - Convert X86 LLVM code to Intel assembly --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a printer that converts from our internal representation
+// of machine-dependent LLVM code to Intel format assembly language.
+// This printer is the output mechanism used by `llc'.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "asm-printer"
+#include "X86IntelAsmPrinter.h"
+#include "X86TargetAsmInfo.h"
+#include "X86.h"
+#include "llvm/CallingConv.h"
+#include "llvm/Constants.h"
+#include "llvm/Module.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/ADT/Statistic.h"
+using namespace llvm;
+
+STATISTIC(EmittedInsts, "Number of machine instrs printed");
+
+std::string X86IntelAsmPrinter::getSectionForFunction(const Function &F) const {
+  // Intel asm always emits functions to _text.
+  return "_text";
+}
+
+/// runOnMachineFunction - This uses the printMachineInstruction()
+/// method to print assembly for each instruction.
+///
+bool X86IntelAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
+  SetupMachineFunction(MF);
+  O << "\n\n";
+
+  // Print out constants referenced by the function
+  EmitConstantPool(MF.getConstantPool());
+
+  // Print out labels for the function.
+  const Function *F = MF.getFunction();
+  unsigned CC = F->getCallingConv();
+
+  // Populate function information map.  Actually, We don't want to populate
+  // non-stdcall or non-fastcall functions' information right now.
+  if (CC == CallingConv::X86_StdCall || CC == CallingConv::X86_FastCall)
+    FunctionInfoMap[F] = *MF.getInfo<X86MachineFunctionInfo>();
+
+  X86SharedAsmPrinter::decorateName(CurrentFnName, F);
+
+  SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
+
+  switch (F->getLinkage()) {
+  default: assert(0 && "Unsupported linkage type!");
+  case Function::InternalLinkage:
+    EmitAlignment(4);
+    break;    
+  case Function::DLLExportLinkage:
+    DLLExportedFns.insert(CurrentFnName);
+    //FALLS THROUGH
+  case Function::ExternalLinkage:
+    O << "\tpublic " << CurrentFnName << "\n";
+    EmitAlignment(4);
+    break;    
+  }
+  
+  O << CurrentFnName << "\tproc near\n";
+  
+  // Print out code for the function.
+  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
+       I != E; ++I) {
+    // Print a label for the basic block if there are any predecessors.
+    if (I->pred_begin() != I->pred_end()) {
+      printBasicBlockLabel(I, true);
+      O << '\n';
+    }
+    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
+         II != E; ++II) {
+      // Print the assembly for the instruction.
+      O << "\t";
+      printMachineInstruction(II);
+    }
+  }
+
+  // Print out jump tables referenced by the function.
+  EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
+
+  O << CurrentFnName << "\tendp\n";
+
+  // We didn't modify anything.
+  return false;
+}
+
+void X86IntelAsmPrinter::printSSECC(const MachineInstr *MI, unsigned Op) {
+  unsigned char value = MI->getOperand(Op).getImmedValue();
+  assert(value <= 7 && "Invalid ssecc argument!");
+  switch (value) {
+  case 0: O << "eq"; break;
+  case 1: O << "lt"; break;
+  case 2: O << "le"; break;
+  case 3: O << "unord"; break;
+  case 4: O << "neq"; break;
+  case 5: O << "nlt"; break;
+  case 6: O << "nle"; break;
+  case 7: O << "ord"; break;
+  }
+}
+
+void X86IntelAsmPrinter::printOp(const MachineOperand &MO, 
+                                 const char *Modifier) {
+  const MRegisterInfo &RI = *TM.getRegisterInfo();
+  switch (MO.getType()) {
+  case MachineOperand::MO_Register: {      
+    if (MRegisterInfo::isPhysicalRegister(MO.getReg())) {
+      unsigned Reg = MO.getReg();
+      if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
+        MVT::ValueType VT = (strcmp(Modifier,"subreg64") == 0) ?
+          MVT::i64 : ((strcmp(Modifier, "subreg32") == 0) ? MVT::i32 :
+                      ((strcmp(Modifier,"subreg16") == 0) ? MVT::i16 :MVT::i8));
+        Reg = getX86SubSuperRegister(Reg, VT);
+      }
+      O << RI.get(Reg).Name;
+    } else
+      O << "reg" << MO.getReg();
+    return;
+  }
+  case MachineOperand::MO_Immediate:
+    O << MO.getImmedValue();
+    return;
+  case MachineOperand::MO_MachineBasicBlock:
+    printBasicBlockLabel(MO.getMachineBasicBlock());
+    return;
+  case MachineOperand::MO_JumpTableIndex: {
+    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
+    if (!isMemOp) O << "OFFSET ";
+    O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
+      << "_" << MO.getJumpTableIndex();
+    return;
+  }    
+  case MachineOperand::MO_ConstantPoolIndex: {
+    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
+    if (!isMemOp) O << "OFFSET ";
+    O << "[" << TAI->getPrivateGlobalPrefix() << "CPI"
+      << getFunctionNumber() << "_" << MO.getConstantPoolIndex();
+    int Offset = MO.getOffset();
+    if (Offset > 0)
+      O << " + " << Offset;
+    else if (Offset < 0)
+      O << Offset;
+    O << "]";
+    return;
+  }
+  case MachineOperand::MO_GlobalAddress: {
+    bool isCallOp = Modifier && !strcmp(Modifier, "call");
+    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
+    GlobalValue *GV = MO.getGlobal();    
+    std::string Name = Mang->getValueName(GV);
+
+    X86SharedAsmPrinter::decorateName(Name, GV);
+
+    if (!isMemOp && !isCallOp) O << "OFFSET ";
+    if (GV->hasDLLImportLinkage()) {
+      // FIXME: This should be fixed with full support of stdcall & fastcall
+      // CC's
+      O << "__imp_";          
+    } 
+    O << Name;
+    int Offset = MO.getOffset();
+    if (Offset > 0)
+      O << " + " << Offset;
+    else if (Offset < 0)
+      O << Offset;
+    return;
+  }
+  case MachineOperand::MO_ExternalSymbol: {
+    bool isCallOp = Modifier && !strcmp(Modifier, "call");
+    if (!isCallOp) O << "OFFSET ";
+    O << TAI->getGlobalPrefix() << MO.getSymbolName();
+    return;
+  }
+  default:
+    O << "<unknown operand type>"; return;
+  }
+}
+
+void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
+                                           const char *Modifier) {
+  assert(isMem(MI, Op) && "Invalid memory reference!");
+
+  const MachineOperand &BaseReg  = MI->getOperand(Op);
+  int ScaleVal                   = MI->getOperand(Op+1).getImmedValue();
+  const MachineOperand &IndexReg = MI->getOperand(Op+2);
+  const MachineOperand &DispSpec = MI->getOperand(Op+3);
+
+  O << "[";
+  bool NeedPlus = false;
+  if (BaseReg.getReg()) {
+    printOp(BaseReg, Modifier);
+    NeedPlus = true;
+  }
+
+  if (IndexReg.getReg()) {
+    if (NeedPlus) O << " + ";
+    if (ScaleVal != 1)
+      O << ScaleVal << "*";
+    printOp(IndexReg, Modifier);
+    NeedPlus = true;
+  }
+
+  if (DispSpec.isGlobalAddress() || DispSpec.isConstantPoolIndex() ||
+      DispSpec.isJumpTableIndex()) {
+    if (NeedPlus)
+      O << " + ";
+    printOp(DispSpec, "mem");
+  } else {
+    int DispVal = DispSpec.getImmedValue();
+    if (DispVal || (!BaseReg.getReg() && !IndexReg.getReg())) {
+      if (NeedPlus)
+        if (DispVal > 0)
+          O << " + ";
+        else {
+          O << " - ";
+          DispVal = -DispVal;
+        }
+      O << DispVal;
+    }
+  }
+  O << "]";
+}
+
+void X86IntelAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
+  O << "\"L" << getFunctionNumber() << "$pb\"\n";
+  O << "\"L" << getFunctionNumber() << "$pb\":";
+}
+
+bool X86IntelAsmPrinter::printAsmMRegister(const MachineOperand &MO,
+                                           const char Mode) {
+  const MRegisterInfo &RI = *TM.getRegisterInfo();
+  unsigned Reg = MO.getReg();
+  switch (Mode) {
+  default: return true;  // Unknown mode.
+  case 'b': // Print QImode register
+    Reg = getX86SubSuperRegister(Reg, MVT::i8);
+    break;
+  case 'h': // Print QImode high register
+    Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
+    break;
+  case 'w': // Print HImode register
+    Reg = getX86SubSuperRegister(Reg, MVT::i16);
+    break;
+  case 'k': // Print SImode register
+    Reg = getX86SubSuperRegister(Reg, MVT::i32);
+    break;
+  }
+
+  O << '%' << RI.get(Reg).Name;
+  return false;
+}
+
+/// PrintAsmOperand - Print out an operand for an inline asm expression.
+///
+bool X86IntelAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
+                                         unsigned AsmVariant, 
+                                         const char *ExtraCode) {
+  // Does this asm operand have a single letter operand modifier?
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+    
+    switch (ExtraCode[0]) {
+    default: return true;  // Unknown modifier.
+    case 'b': // Print QImode register
+    case 'h': // Print QImode high register
+    case 'w': // Print HImode register
+    case 'k': // Print SImode register
+      return printAsmMRegister(MI->getOperand(OpNo), ExtraCode[0]);
+    }
+  }
+  
+  printOperand(MI, OpNo);
+  return false;
+}
+
+bool X86IntelAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
+                                               unsigned OpNo,
+                                               unsigned AsmVariant, 
+                                               const char *ExtraCode) {
+  if (ExtraCode && ExtraCode[0])
+    return true; // Unknown modifier.
+  printMemReference(MI, OpNo);
+  return false;
+}
+
+/// printMachineInstruction -- Print out a single X86 LLVM instruction
+/// MI in Intel syntax to the current output stream.
+///
+void X86IntelAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
+  ++EmittedInsts;
+
+  // See if a truncate instruction can be turned into a nop.
+  switch (MI->getOpcode()) {
+  default: break;
+  case X86::TRUNC_64to32:
+  case X86::TRUNC_64to16:
+  case X86::TRUNC_32to16:
+  case X86::TRUNC_32to8:
+  case X86::TRUNC_16to8:
+  case X86::TRUNC_32_to8:
+  case X86::TRUNC_16_to8: {
+    const MachineOperand &MO0 = MI->getOperand(0);
+    const MachineOperand &MO1 = MI->getOperand(1);
+    unsigned Reg0 = MO0.getReg();
+    unsigned Reg1 = MO1.getReg();
+    unsigned Opc = MI->getOpcode();
+    if (Opc == X86::TRUNC_64to32)
+      Reg1 = getX86SubSuperRegister(Reg1, MVT::i32);
+    else if (Opc == X86::TRUNC_32to16 || Opc == X86::TRUNC_64to16)
+      Reg1 = getX86SubSuperRegister(Reg1, MVT::i16);
+    else
+      Reg1 = getX86SubSuperRegister(Reg1, MVT::i8);
+    O << TAI->getCommentString() << " TRUNCATE ";
+    if (Reg0 != Reg1)
+      O << "\n\t";
+    break;
+  }
+  case X86::PsMOVZX64rr32:
+    O << TAI->getCommentString() << " ZERO-EXTEND " << "\n\t";
+    break;
+  }
+
+  // Call the autogenerated instruction printer routines.
+  printInstruction(MI);
+}
+
+bool X86IntelAsmPrinter::doInitialization(Module &M) {
+  X86SharedAsmPrinter::doInitialization(M);
+  
+  Mang->markCharUnacceptable('.');
+
+  O << "\t.686\n\t.model flat\n\n";
+
+  // Emit declarations for external functions.
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+    if (I->isDeclaration()) {
+      std::string Name = Mang->getValueName(I);
+      X86SharedAsmPrinter::decorateName(Name, I);
+
+      O << "\textern " ;
+      if (I->hasDLLImportLinkage()) {
+        O << "__imp_";
+      }      
+      O << Name << ":near\n";
+    }
+  
+  // Emit declarations for external globals.  Note that VC++ always declares
+  // external globals to have type byte, and if that's good enough for VC++...
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    if (I->isDeclaration()) {
+      std::string Name = Mang->getValueName(I);
+
+      O << "\textern " ;
+      if (I->hasDLLImportLinkage()) {
+        O << "__imp_";
+      }      
+      O << Name << ":byte\n";
+    }
+  }
+
+  return false;
+}
+
+bool X86IntelAsmPrinter::doFinalization(Module &M) {
+  const TargetData *TD = TM.getTargetData();
+
+  // Print out module-level global variables here.
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    if (I->isDeclaration()) continue;   // External global require no code
+    
+    // Check to see if this is a special global used by LLVM, if so, emit it.
+    if (EmitSpecialLLVMGlobal(I))
+      continue;
+    
+    std::string name = Mang->getValueName(I);
+    Constant *C = I->getInitializer();
+    unsigned Align = TD->getPreferredAlignmentLog(I);
+    bool bCustomSegment = false;
+
+    switch (I->getLinkage()) {
+    case GlobalValue::LinkOnceLinkage:
+    case GlobalValue::WeakLinkage:
+      SwitchToDataSection("");
+      O << name << "?\tsegment common 'COMMON'\n";
+      bCustomSegment = true;
+      // FIXME: the default alignment is 16 bytes, but 1, 2, 4, and 256
+      // are also available.
+      break;
+    case GlobalValue::AppendingLinkage:
+      SwitchToDataSection("");
+      O << name << "?\tsegment public 'DATA'\n";
+      bCustomSegment = true;
+      // FIXME: the default alignment is 16 bytes, but 1, 2, 4, and 256
+      // are also available.
+      break;
+    case GlobalValue::DLLExportLinkage:
+      DLLExportedGVs.insert(name);
+      // FALL THROUGH
+    case GlobalValue::ExternalLinkage:
+      O << "\tpublic " << name << "\n";
+      // FALL THROUGH
+    case GlobalValue::InternalLinkage:
+      SwitchToDataSection(TAI->getDataSection(), I);
+      break;
+    default:
+      assert(0 && "Unknown linkage type!");
+    }
+
+    if (!bCustomSegment)
+      EmitAlignment(Align, I);
+
+    O << name << ":\t\t\t\t" << TAI->getCommentString()
+      << " " << I->getName() << '\n';
+
+    EmitGlobalConstant(C);
+
+    if (bCustomSegment)
+      O << name << "?\tends\n";
+  }
+
+    // Output linker support code for dllexported globals
+  if ((DLLExportedGVs.begin() != DLLExportedGVs.end()) ||
+      (DLLExportedFns.begin() != DLLExportedFns.end())) {
+    SwitchToDataSection("");
+    O << "; WARNING: The following code is valid only with MASM v8.x and (possible) higher\n"
+      << "; This version of MASM is usually shipped with Microsoft Visual Studio 2005\n"
+      << "; or (possible) further versions. Unfortunately, there is no way to support\n"
+      << "; dllexported symbols in the earlier versions of MASM in fully automatic way\n\n";
+    O << "_drectve\t segment info alias('.drectve')\n";
+  }
+
+  for (std::set<std::string>::iterator i = DLLExportedGVs.begin(),
+         e = DLLExportedGVs.end();
+         i != e; ++i) {
+    O << "\t db ' /EXPORT:" << *i << ",data'\n";
+  }    
+
+  for (std::set<std::string>::iterator i = DLLExportedFns.begin(),
+         e = DLLExportedFns.end();
+         i != e; ++i) {
+    O << "\t db ' /EXPORT:" << *i << "'\n";
+  }    
+
+  if ((DLLExportedGVs.begin() != DLLExportedGVs.end()) ||
+      (DLLExportedFns.begin() != DLLExportedFns.end())) {
+    O << "_drectve\t ends\n";    
+  }
+  
+  // Bypass X86SharedAsmPrinter::doFinalization().
+  AsmPrinter::doFinalization(M);
+  SwitchToDataSection("");
+  O << "\tend\n";
+  return false; // success
+}
+
+void X86IntelAsmPrinter::EmitString(const ConstantArray *CVA) const {
+  unsigned NumElts = CVA->getNumOperands();
+  if (NumElts) {
+    // ML does not have escape sequences except '' for '.  It also has a maximum
+    // string length of 255.
+    unsigned len = 0;
+    bool inString = false;
+    for (unsigned i = 0; i < NumElts; i++) {
+      int n = cast<ConstantInt>(CVA->getOperand(i))->getZExtValue() & 255;
+      if (len == 0)
+        O << "\tdb ";
+
+      if (n >= 32 && n <= 127) {
+        if (!inString) {
+          if (len > 0) {
+            O << ",'";
+            len += 2;
+          } else {
+            O << "'";
+            len++;
+          }
+          inString = true;
+        }
+        if (n == '\'') {
+          O << "'";
+          len++;
+        }
+        O << char(n);
+      } else {
+        if (inString) {
+          O << "'";
+          len++;
+          inString = false;
+        }
+        if (len > 0) {
+          O << ",";
+          len++;
+        }
+        O << n;
+        len += 1 + (n > 9) + (n > 99);
+      }
+
+      if (len > 60) {
+        if (inString) {
+          O << "'";
+          inString = false;
+        }
+        O << "\n";
+        len = 0;
+      }
+    }
+
+    if (len > 0) {
+      if (inString)
+        O << "'";
+      O << "\n";
+    }
+  }
+}
+
+// Include the auto-generated portion of the assembly writer.
+#include "X86GenAsmWriter1.inc"