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

1 files changed, 1210 insertions, 0 deletions

diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
new file mode 100644
index 0000000..586472c
--- /dev/null
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -0,0 +1,1210 @@
+//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
+//
+//                     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 implements the AsmPrinter class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Constants.h"
+#include "llvm/Module.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/Streams.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetMachine.h"
+#include <cerrno>
+using namespace llvm;
+
+static cl::opt<bool>
+AsmVerbose("asm-verbose", cl::Hidden, cl::desc("Add comments to directives."));
+
+char AsmPrinter::ID = 0;
+AsmPrinter::AsmPrinter(std::ostream &o, TargetMachine &tm,
+                       const TargetAsmInfo *T)
+  : MachineFunctionPass((intptr_t)&ID), FunctionNumber(0), O(o), TM(tm), TAI(T)
+{}
+
+std::string AsmPrinter::getSectionForFunction(const Function &F) const {
+  return TAI->getTextSection();
+}
+
+
+/// SwitchToTextSection - Switch to the specified text section of the executable
+/// if we are not already in it!
+///
+void AsmPrinter::SwitchToTextSection(const char *NewSection,
+                                     const GlobalValue *GV) {
+  std::string NS;
+  if (GV && GV->hasSection())
+    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
+  else
+    NS = NewSection;
+  
+  // If we're already in this section, we're done.
+  if (CurrentSection == NS) return;
+
+  // Close the current section, if applicable.
+  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
+    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << "\n";
+
+  CurrentSection = NS;
+
+  if (!CurrentSection.empty())
+    O << CurrentSection << TAI->getTextSectionStartSuffix() << '\n';
+}
+
+/// SwitchToDataSection - Switch to the specified data section of the executable
+/// if we are not already in it!
+///
+void AsmPrinter::SwitchToDataSection(const char *NewSection,
+                                     const GlobalValue *GV) {
+  std::string NS;
+  if (GV && GV->hasSection())
+    NS = TAI->getSwitchToSectionDirective() + GV->getSection();
+  else
+    NS = NewSection;
+  
+  // If we're already in this section, we're done.
+  if (CurrentSection == NS) return;
+
+  // Close the current section, if applicable.
+  if (TAI->getSectionEndDirectiveSuffix() && !CurrentSection.empty())
+    O << CurrentSection << TAI->getSectionEndDirectiveSuffix() << "\n";
+
+  CurrentSection = NS;
+  
+  if (!CurrentSection.empty())
+    O << CurrentSection << TAI->getDataSectionStartSuffix() << '\n';
+}
+
+
+bool AsmPrinter::doInitialization(Module &M) {
+  Mang = new Mangler(M, TAI->getGlobalPrefix());
+  
+  if (!M.getModuleInlineAsm().empty())
+    O << TAI->getCommentString() << " Start of file scope inline assembly\n"
+      << M.getModuleInlineAsm()
+      << "\n" << TAI->getCommentString()
+      << " End of file scope inline assembly\n";
+
+  SwitchToDataSection("");   // Reset back to no section.
+  
+  if (MachineModuleInfo *MMI = getAnalysisToUpdate<MachineModuleInfo>()) {
+    MMI->AnalyzeModule(M);
+  }
+  
+  return false;
+}
+
+bool AsmPrinter::doFinalization(Module &M) {
+  if (TAI->getWeakRefDirective()) {
+    if (!ExtWeakSymbols.empty())
+      SwitchToDataSection("");
+
+    for (std::set<const GlobalValue*>::iterator i = ExtWeakSymbols.begin(),
+         e = ExtWeakSymbols.end(); i != e; ++i) {
+      const GlobalValue *GV = *i;
+      std::string Name = Mang->getValueName(GV);
+      O << TAI->getWeakRefDirective() << Name << "\n";
+    }
+  }
+
+  if (TAI->getSetDirective()) {
+    if (!M.alias_empty())
+      SwitchToTextSection(TAI->getTextSection());
+
+    O << "\n";
+    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
+         I!=E; ++I) {
+      std::string Name = Mang->getValueName(I);
+      std::string Target;
+      
+      if (const GlobalValue *GV = I->getAliasedGlobal())
+        Target = Mang->getValueName(GV);
+      else
+        assert(0 && "Unsupported aliasee");
+      
+      if (I->hasExternalLinkage())
+        O << "\t.globl\t" << Name << "\n";
+      else if (I->hasWeakLinkage())
+        O << TAI->getWeakRefDirective() << Name << "\n";
+      else if (!I->hasInternalLinkage())
+        assert(0 && "Invalid alias linkage");
+      
+      O << TAI->getSetDirective() << Name << ", " << Target << "\n";
+    }
+  }
+
+  delete Mang; Mang = 0;
+  return false;
+}
+
+void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
+  // What's my mangled name?
+  CurrentFnName = Mang->getValueName(MF.getFunction());
+  IncrementFunctionNumber();
+}
+
+/// EmitConstantPool - Print to the current output stream assembly
+/// representations of the constants in the constant pool MCP. This is
+/// used to print out constants which have been "spilled to memory" by
+/// the code generator.
+///
+void AsmPrinter::EmitConstantPool(MachineConstantPool *MCP) {
+  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
+  if (CP.empty()) return;
+
+  // Some targets require 4-, 8-, and 16- byte constant literals to be placed
+  // in special sections.
+  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > FourByteCPs;
+  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > EightByteCPs;
+  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > SixteenByteCPs;
+  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > OtherCPs;
+  std::vector<std::pair<MachineConstantPoolEntry,unsigned> > TargetCPs;
+  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
+    MachineConstantPoolEntry CPE = CP[i];
+    const Type *Ty = CPE.getType();
+    if (TAI->getFourByteConstantSection() &&
+        TM.getTargetData()->getTypeSize(Ty) == 4)
+      FourByteCPs.push_back(std::make_pair(CPE, i));
+    else if (TAI->getEightByteConstantSection() &&
+             TM.getTargetData()->getTypeSize(Ty) == 8)
+      EightByteCPs.push_back(std::make_pair(CPE, i));
+    else if (TAI->getSixteenByteConstantSection() &&
+             TM.getTargetData()->getTypeSize(Ty) == 16)
+      SixteenByteCPs.push_back(std::make_pair(CPE, i));
+    else
+      OtherCPs.push_back(std::make_pair(CPE, i));
+  }
+
+  unsigned Alignment = MCP->getConstantPoolAlignment();
+  EmitConstantPool(Alignment, TAI->getFourByteConstantSection(), FourByteCPs);
+  EmitConstantPool(Alignment, TAI->getEightByteConstantSection(), EightByteCPs);
+  EmitConstantPool(Alignment, TAI->getSixteenByteConstantSection(),
+                   SixteenByteCPs);
+  EmitConstantPool(Alignment, TAI->getConstantPoolSection(), OtherCPs);
+}
+
+void AsmPrinter::EmitConstantPool(unsigned Alignment, const char *Section,
+               std::vector<std::pair<MachineConstantPoolEntry,unsigned> > &CP) {
+  if (CP.empty()) return;
+
+  SwitchToDataSection(Section);
+  EmitAlignment(Alignment);
+  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
+    O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
+      << CP[i].second << ":\t\t\t\t\t" << TAI->getCommentString() << " ";
+    WriteTypeSymbolic(O, CP[i].first.getType(), 0) << '\n';
+    if (CP[i].first.isMachineConstantPoolEntry())
+      EmitMachineConstantPoolValue(CP[i].first.Val.MachineCPVal);
+     else
+      EmitGlobalConstant(CP[i].first.Val.ConstVal);
+    if (i != e-1) {
+      const Type *Ty = CP[i].first.getType();
+      unsigned EntSize =
+        TM.getTargetData()->getTypeSize(Ty);
+      unsigned ValEnd = CP[i].first.getOffset() + EntSize;
+      // Emit inter-object padding for alignment.
+      EmitZeros(CP[i+1].first.getOffset()-ValEnd);
+    }
+  }
+}
+
+/// EmitJumpTableInfo - Print assembly representations of the jump tables used
+/// by the current function to the current output stream.  
+///
+void AsmPrinter::EmitJumpTableInfo(MachineJumpTableInfo *MJTI,
+                                   MachineFunction &MF) {
+  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+  if (JT.empty()) return;
+  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
+  
+  // Use JumpTableDirective otherwise honor the entry size from the jump table
+  // info.
+  const char *JTEntryDirective = TAI->getJumpTableDirective();
+  bool HadJTEntryDirective = JTEntryDirective != NULL;
+  if (!HadJTEntryDirective) {
+    JTEntryDirective = MJTI->getEntrySize() == 4 ?
+      TAI->getData32bitsDirective() : TAI->getData64bitsDirective();
+  }
+  
+  // Pick the directive to use to print the jump table entries, and switch to 
+  // the appropriate section.
+  TargetLowering *LoweringInfo = TM.getTargetLowering();
+
+  const char* JumpTableDataSection = TAI->getJumpTableDataSection();  
+  if ((IsPic && !(LoweringInfo && LoweringInfo->usesGlobalOffsetTable())) ||
+     !JumpTableDataSection) {
+    // In PIC mode, we need to emit the jump table to the same section as the
+    // function body itself, otherwise the label differences won't make sense.
+    // We should also do if the section name is NULL.
+    const Function *F = MF.getFunction();
+    SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
+  } else {
+    SwitchToDataSection(JumpTableDataSection);
+  }
+  
+  EmitAlignment(Log2_32(MJTI->getAlignment()));
+  
+  for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+    const std::vector<MachineBasicBlock*> &JTBBs = JT[i].MBBs;
+    
+    // If this jump table was deleted, ignore it. 
+    if (JTBBs.empty()) continue;
+
+    // For PIC codegen, if possible we want to use the SetDirective to reduce
+    // the number of relocations the assembler will generate for the jump table.
+    // Set directives are all printed before the jump table itself.
+    std::set<MachineBasicBlock*> EmittedSets;
+    if (TAI->getSetDirective() && IsPic)
+      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
+        if (EmittedSets.insert(JTBBs[ii]).second)
+          printSetLabel(i, JTBBs[ii]);
+    
+    // On some targets (e.g. darwin) we want to emit two consequtive labels
+    // before each jump table.  The first label is never referenced, but tells
+    // the assembler and linker the extents of the jump table object.  The
+    // second label is actually referenced by the code.
+    if (const char *JTLabelPrefix = TAI->getJumpTableSpecialLabelPrefix())
+      O << JTLabelPrefix << "JTI" << getFunctionNumber() << '_' << i << ":\n";
+    
+    O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() 
+      << '_' << i << ":\n";
+    
+    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
+      O << JTEntryDirective << ' ';
+      // If we have emitted set directives for the jump table entries, print 
+      // them rather than the entries themselves.  If we're emitting PIC, then
+      // emit the table entries as differences between two text section labels.
+      // If we're emitting non-PIC code, then emit the entries as direct
+      // references to the target basic blocks.
+      if (!EmittedSets.empty()) {
+        O << TAI->getPrivateGlobalPrefix() << getFunctionNumber()
+          << '_' << i << "_set_" << JTBBs[ii]->getNumber();
+      } else if (IsPic) {
+        printBasicBlockLabel(JTBBs[ii], false, false);
+        // If the arch uses custom Jump Table directives, don't calc relative to
+        // JT
+        if (!HadJTEntryDirective) 
+          O << '-' << TAI->getPrivateGlobalPrefix() << "JTI"
+            << getFunctionNumber() << '_' << i;
+      } else {
+        printBasicBlockLabel(JTBBs[ii], false, false);
+      }
+      O << '\n';
+    }
+  }
+}
+
+/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
+/// special global used by LLVM.  If so, emit it and return true, otherwise
+/// do nothing and return false.
+bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
+  // Ignore debug and non-emitted data.
+  if (GV->getSection() == "llvm.metadata") return true;
+  
+  if (!GV->hasAppendingLinkage()) return false;
+
+  assert(GV->hasInitializer() && "Not a special LLVM global!");
+  
+  if (GV->getName() == "llvm.used") {
+    if (TAI->getUsedDirective() != 0)    // No need to emit this at all.
+      EmitLLVMUsedList(GV->getInitializer());
+    return true;
+  }
+
+  const TargetData *TD = TM.getTargetData();
+  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
+  if (GV->getName() == "llvm.global_ctors" && GV->use_empty()) {
+    SwitchToDataSection(TAI->getStaticCtorsSection());
+    EmitAlignment(Align, 0);
+    EmitXXStructorList(GV->getInitializer());
+    return true;
+  } 
+  
+  if (GV->getName() == "llvm.global_dtors" && GV->use_empty()) {
+    SwitchToDataSection(TAI->getStaticDtorsSection());
+    EmitAlignment(Align, 0);
+    EmitXXStructorList(GV->getInitializer());
+    return true;
+  }
+  
+  return false;
+}
+
+/// EmitLLVMUsedList - For targets that define a TAI::UsedDirective, mark each
+/// global in the specified llvm.used list as being used with this directive.
+void AsmPrinter::EmitLLVMUsedList(Constant *List) {
+  const char *Directive = TAI->getUsedDirective();
+
+  // Should be an array of 'sbyte*'.
+  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
+  if (InitList == 0) return;
+  
+  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+    O << Directive;
+    EmitConstantValueOnly(InitList->getOperand(i));
+    O << "\n";
+  }
+}
+
+/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the 
+/// function pointers, ignoring the init priority.
+void AsmPrinter::EmitXXStructorList(Constant *List) {
+  // Should be an array of '{ int, void ()* }' structs.  The first value is the
+  // init priority, which we ignore.
+  if (!isa<ConstantArray>(List)) return;
+  ConstantArray *InitList = cast<ConstantArray>(List);
+  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
+    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
+      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
+
+      if (CS->getOperand(1)->isNullValue())
+        return;  // Found a null terminator, exit printing.
+      // Emit the function pointer.
+      EmitGlobalConstant(CS->getOperand(1));
+    }
+}
+
+/// getGlobalLinkName - Returns the asm/link name of of the specified
+/// global variable.  Should be overridden by each target asm printer to
+/// generate the appropriate value.
+const std::string AsmPrinter::getGlobalLinkName(const GlobalVariable *GV) const{
+  std::string LinkName;
+  
+  if (isa<Function>(GV)) {
+    LinkName += TAI->getFunctionAddrPrefix();
+    LinkName += Mang->getValueName(GV);
+    LinkName += TAI->getFunctionAddrSuffix();
+  } else {
+    LinkName += TAI->getGlobalVarAddrPrefix();
+    LinkName += Mang->getValueName(GV);
+    LinkName += TAI->getGlobalVarAddrSuffix();
+  }  
+  
+  return LinkName;
+}
+
+/// EmitExternalGlobal - Emit the external reference to a global variable.
+/// Should be overridden if an indirect reference should be used.
+void AsmPrinter::EmitExternalGlobal(const GlobalVariable *GV) {
+  O << getGlobalLinkName(GV);
+}
+
+
+
+//===----------------------------------------------------------------------===//
+/// LEB 128 number encoding.
+
+/// PrintULEB128 - Print a series of hexidecimal values (separated by commas)
+/// representing an unsigned leb128 value.
+void AsmPrinter::PrintULEB128(unsigned Value) const {
+  do {
+    unsigned Byte = Value & 0x7f;
+    Value >>= 7;
+    if (Value) Byte |= 0x80;
+    O << "0x" << std::hex << Byte << std::dec;
+    if (Value) O << ", ";
+  } while (Value);
+}
+
+/// SizeULEB128 - Compute the number of bytes required for an unsigned leb128
+/// value.
+unsigned AsmPrinter::SizeULEB128(unsigned Value) {
+  unsigned Size = 0;
+  do {
+    Value >>= 7;
+    Size += sizeof(int8_t);
+  } while (Value);
+  return Size;
+}
+
+/// PrintSLEB128 - Print a series of hexidecimal values (separated by commas)
+/// representing a signed leb128 value.
+void AsmPrinter::PrintSLEB128(int Value) const {
+  int Sign = Value >> (8 * sizeof(Value) - 1);
+  bool IsMore;
+  
+  do {
+    unsigned Byte = Value & 0x7f;
+    Value >>= 7;
+    IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
+    if (IsMore) Byte |= 0x80;
+    O << "0x" << std::hex << Byte << std::dec;
+    if (IsMore) O << ", ";
+  } while (IsMore);
+}
+
+/// SizeSLEB128 - Compute the number of bytes required for a signed leb128
+/// value.
+unsigned AsmPrinter::SizeSLEB128(int Value) {
+  unsigned Size = 0;
+  int Sign = Value >> (8 * sizeof(Value) - 1);
+  bool IsMore;
+  
+  do {
+    unsigned Byte = Value & 0x7f;
+    Value >>= 7;
+    IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
+    Size += sizeof(int8_t);
+  } while (IsMore);
+  return Size;
+}
+
+//===--------------------------------------------------------------------===//
+// Emission and print routines
+//
+
+/// PrintHex - Print a value as a hexidecimal value.
+///
+void AsmPrinter::PrintHex(int Value) const { 
+  O << "0x" << std::hex << Value << std::dec;
+}
+
+/// EOL - Print a newline character to asm stream.  If a comment is present
+/// then it will be printed first.  Comments should not contain '\n'.
+void AsmPrinter::EOL() const {
+  O << "\n";
+}
+void AsmPrinter::EOL(const std::string &Comment) const {
+  if (AsmVerbose && !Comment.empty()) {
+    O << "\t"
+      << TAI->getCommentString()
+      << " "
+      << Comment;
+  }
+  O << "\n";
+}
+
+/// EmitULEB128Bytes - Emit an assembler byte data directive to compose an
+/// unsigned leb128 value.
+void AsmPrinter::EmitULEB128Bytes(unsigned Value) const {
+  if (TAI->hasLEB128()) {
+    O << "\t.uleb128\t"
+      << Value;
+  } else {
+    O << TAI->getData8bitsDirective();
+    PrintULEB128(Value);
+  }
+}
+
+/// EmitSLEB128Bytes - print an assembler byte data directive to compose a
+/// signed leb128 value.
+void AsmPrinter::EmitSLEB128Bytes(int Value) const {
+  if (TAI->hasLEB128()) {
+    O << "\t.sleb128\t"
+      << Value;
+  } else {
+    O << TAI->getData8bitsDirective();
+    PrintSLEB128(Value);
+  }
+}
+
+/// EmitInt8 - Emit a byte directive and value.
+///
+void AsmPrinter::EmitInt8(int Value) const {
+  O << TAI->getData8bitsDirective();
+  PrintHex(Value & 0xFF);
+}
+
+/// EmitInt16 - Emit a short directive and value.
+///
+void AsmPrinter::EmitInt16(int Value) const {
+  O << TAI->getData16bitsDirective();
+  PrintHex(Value & 0xFFFF);
+}
+
+/// EmitInt32 - Emit a long directive and value.
+///
+void AsmPrinter::EmitInt32(int Value) const {
+  O << TAI->getData32bitsDirective();
+  PrintHex(Value);
+}
+
+/// EmitInt64 - Emit a long long directive and value.
+///
+void AsmPrinter::EmitInt64(uint64_t Value) const {
+  if (TAI->getData64bitsDirective()) {
+    O << TAI->getData64bitsDirective();
+    PrintHex(Value);
+  } else {
+    if (TM.getTargetData()->isBigEndian()) {
+      EmitInt32(unsigned(Value >> 32)); O << "\n";
+      EmitInt32(unsigned(Value));
+    } else {
+      EmitInt32(unsigned(Value)); O << "\n";
+      EmitInt32(unsigned(Value >> 32));
+    }
+  }
+}
+
+/// toOctal - Convert the low order bits of X into an octal digit.
+///
+static inline char toOctal(int X) {
+  return (X&7)+'0';
+}
+
+/// printStringChar - Print a char, escaped if necessary.
+///
+static void printStringChar(std::ostream &O, unsigned char C) {
+  if (C == '"') {
+    O << "\\\"";
+  } else if (C == '\\') {
+    O << "\\\\";
+  } else if (isprint(C)) {
+    O << C;
+  } else {
+    switch(C) {
+    case '\b': O << "\\b"; break;
+    case '\f': O << "\\f"; break;
+    case '\n': O << "\\n"; break;
+    case '\r': O << "\\r"; break;
+    case '\t': O << "\\t"; break;
+    default:
+      O << '\\';
+      O << toOctal(C >> 6);
+      O << toOctal(C >> 3);
+      O << toOctal(C >> 0);
+      break;
+    }
+  }
+}
+
+/// EmitString - Emit a string with quotes and a null terminator.
+/// Special characters are emitted properly.
+/// \literal (Eg. '\t') \endliteral
+void AsmPrinter::EmitString(const std::string &String) const {
+  const char* AscizDirective = TAI->getAscizDirective();
+  if (AscizDirective)
+    O << AscizDirective;
+  else
+    O << TAI->getAsciiDirective();
+  O << "\"";
+  for (unsigned i = 0, N = String.size(); i < N; ++i) {
+    unsigned char C = String[i];
+    printStringChar(O, C);
+  }
+  if (AscizDirective)
+    O << "\"";
+  else
+    O << "\\0\"";
+}
+
+
+//===----------------------------------------------------------------------===//
+
+// EmitAlignment - Emit an alignment directive to the specified power of
+// two boundary.  For example, if you pass in 3 here, you will get an 8
+// byte alignment.  If a global value is specified, and if that global has
+// an explicit alignment requested, it will unconditionally override the
+// alignment request.  However, if ForcedAlignBits is specified, this value
+// has final say: the ultimate alignment will be the max of ForcedAlignBits
+// and the alignment computed with NumBits and the global.
+//
+// The algorithm is:
+//     Align = NumBits;
+//     if (GV && GV->hasalignment) Align = GV->getalignment();
+//     Align = std::max(Align, ForcedAlignBits);
+//
+void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
+                               unsigned ForcedAlignBits) const {
+  if (GV && GV->getAlignment())
+    NumBits = Log2_32(GV->getAlignment());
+  NumBits = std::max(NumBits, ForcedAlignBits);
+  
+  if (NumBits == 0) return;   // No need to emit alignment.
+  if (TAI->getAlignmentIsInBytes()) NumBits = 1 << NumBits;
+  O << TAI->getAlignDirective() << NumBits << "\n";
+}
+
+    
+/// EmitZeros - Emit a block of zeros.
+///
+void AsmPrinter::EmitZeros(uint64_t NumZeros) const {
+  if (NumZeros) {
+    if (TAI->getZeroDirective()) {
+      O << TAI->getZeroDirective() << NumZeros;
+      if (TAI->getZeroDirectiveSuffix())
+        O << TAI->getZeroDirectiveSuffix();
+      O << "\n";
+    } else {
+      for (; NumZeros; --NumZeros)
+        O << TAI->getData8bitsDirective() << "0\n";
+    }
+  }
+}
+
+// Print out the specified constant, without a storage class.  Only the
+// constants valid in constant expressions can occur here.
+void AsmPrinter::EmitConstantValueOnly(const Constant *CV) {
+  if (CV->isNullValue() || isa<UndefValue>(CV))
+    O << "0";
+  else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+    O << CI->getZExtValue();
+  } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) {
+    // This is a constant address for a global variable or function. Use the
+    // name of the variable or function as the address value, possibly
+    // decorating it with GlobalVarAddrPrefix/Suffix or
+    // FunctionAddrPrefix/Suffix (these all default to "" )
+    if (isa<Function>(GV)) {
+      O << TAI->getFunctionAddrPrefix()
+        << Mang->getValueName(GV)
+        << TAI->getFunctionAddrSuffix();
+    } else {
+      O << TAI->getGlobalVarAddrPrefix()
+        << Mang->getValueName(GV)
+        << TAI->getGlobalVarAddrSuffix();
+    }
+  } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
+    const TargetData *TD = TM.getTargetData();
+    unsigned Opcode = CE->getOpcode();    
+    switch (Opcode) {
+    case Instruction::GetElementPtr: {
+      // generate a symbolic expression for the byte address
+      const Constant *ptrVal = CE->getOperand(0);
+      SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end());
+      if (int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0],
+                                                idxVec.size())) {
+        if (Offset)
+          O << "(";
+        EmitConstantValueOnly(ptrVal);
+        if (Offset > 0)
+          O << ") + " << Offset;
+        else if (Offset < 0)
+          O << ") - " << -Offset;
+      } else {
+        EmitConstantValueOnly(ptrVal);
+      }
+      break;
+    }
+    case Instruction::Trunc:
+    case Instruction::ZExt:
+    case Instruction::SExt:
+    case Instruction::FPTrunc:
+    case Instruction::FPExt:
+    case Instruction::UIToFP:
+    case Instruction::SIToFP:
+    case Instruction::FPToUI:
+    case Instruction::FPToSI:
+      assert(0 && "FIXME: Don't yet support this kind of constant cast expr");
+      break;
+    case Instruction::BitCast:
+      return EmitConstantValueOnly(CE->getOperand(0));
+
+    case Instruction::IntToPtr: {
+      // Handle casts to pointers by changing them into casts to the appropriate
+      // integer type.  This promotes constant folding and simplifies this code.
+      Constant *Op = CE->getOperand(0);
+      Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(), false/*ZExt*/);
+      return EmitConstantValueOnly(Op);
+    }
+      
+      
+    case Instruction::PtrToInt: {
+      // Support only foldable casts to/from pointers that can be eliminated by
+      // changing the pointer to the appropriately sized integer type.
+      Constant *Op = CE->getOperand(0);
+      const Type *Ty = CE->getType();
+
+      // We can emit the pointer value into this slot if the slot is an
+      // integer slot greater or equal to the size of the pointer.
+      if (Ty->isInteger() &&
+          TD->getTypeSize(Ty) >= TD->getTypeSize(Op->getType()))
+        return EmitConstantValueOnly(Op);
+      
+      assert(0 && "FIXME: Don't yet support this kind of constant cast expr");
+      EmitConstantValueOnly(Op);
+      break;
+    }
+    case Instruction::Add:
+    case Instruction::Sub:
+      O << "(";
+      EmitConstantValueOnly(CE->getOperand(0));
+      O << (Opcode==Instruction::Add ? ") + (" : ") - (");
+      EmitConstantValueOnly(CE->getOperand(1));
+      O << ")";
+      break;
+    default:
+      assert(0 && "Unsupported operator!");
+    }
+  } else {
+    assert(0 && "Unknown constant value!");
+  }
+}
+
+/// printAsCString - Print the specified array as a C compatible string, only if
+/// the predicate isString is true.
+///
+static void printAsCString(std::ostream &O, const ConstantArray *CVA,
+                           unsigned LastElt) {
+  assert(CVA->isString() && "Array is not string compatible!");
+
+  O << "\"";
+  for (unsigned i = 0; i != LastElt; ++i) {
+    unsigned char C =
+        (unsigned char)cast<ConstantInt>(CVA->getOperand(i))->getZExtValue();
+    printStringChar(O, C);
+  }
+  O << "\"";
+}
+
+/// EmitString - Emit a zero-byte-terminated string constant.
+///
+void AsmPrinter::EmitString(const ConstantArray *CVA) const {
+  unsigned NumElts = CVA->getNumOperands();
+  if (TAI->getAscizDirective() && NumElts && 
+      cast<ConstantInt>(CVA->getOperand(NumElts-1))->getZExtValue() == 0) {
+    O << TAI->getAscizDirective();
+    printAsCString(O, CVA, NumElts-1);
+  } else {
+    O << TAI->getAsciiDirective();
+    printAsCString(O, CVA, NumElts);
+  }
+  O << "\n";
+}
+
+/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
+///
+void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
+  const TargetData *TD = TM.getTargetData();
+
+  if (CV->isNullValue() || isa<UndefValue>(CV)) {
+    EmitZeros(TD->getTypeSize(CV->getType()));
+    return;
+  } else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
+    if (CVA->isString()) {
+      EmitString(CVA);
+    } else { // Not a string.  Print the values in successive locations
+      for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i)
+        EmitGlobalConstant(CVA->getOperand(i));
+    }
+    return;
+  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
+    // Print the fields in successive locations. Pad to align if needed!
+    const StructLayout *cvsLayout = TD->getStructLayout(CVS->getType());
+    uint64_t sizeSoFar = 0;
+    for (unsigned i = 0, e = CVS->getNumOperands(); i != e; ++i) {
+      const Constant* field = CVS->getOperand(i);
+
+      // Check if padding is needed and insert one or more 0s.
+      uint64_t fieldSize = TD->getTypeSize(field->getType());
+      uint64_t padSize = ((i == e-1? cvsLayout->getSizeInBytes()
+                           : cvsLayout->getElementOffset(i+1))
+                          - cvsLayout->getElementOffset(i)) - fieldSize;
+      sizeSoFar += fieldSize + padSize;
+
+      // Now print the actual field value
+      EmitGlobalConstant(field);
+
+      // Insert the field padding unless it's zero bytes...
+      EmitZeros(padSize);
+    }
+    assert(sizeSoFar == cvsLayout->getSizeInBytes() &&
+           "Layout of constant struct may be incorrect!");
+    return;
+  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
+    // FP Constants are printed as integer constants to avoid losing
+    // precision...
+    double Val = CFP->getValue();
+    if (CFP->getType() == Type::DoubleTy) {
+      if (TAI->getData64bitsDirective())
+        O << TAI->getData64bitsDirective() << DoubleToBits(Val) << "\t"
+          << TAI->getCommentString() << " double value: " << Val << "\n";
+      else if (TD->isBigEndian()) {
+        O << TAI->getData32bitsDirective() << unsigned(DoubleToBits(Val) >> 32)
+          << "\t" << TAI->getCommentString()
+          << " double most significant word " << Val << "\n";
+        O << TAI->getData32bitsDirective() << unsigned(DoubleToBits(Val))
+          << "\t" << TAI->getCommentString()
+          << " double least significant word " << Val << "\n";
+      } else {
+        O << TAI->getData32bitsDirective() << unsigned(DoubleToBits(Val))
+          << "\t" << TAI->getCommentString()
+          << " double least significant word " << Val << "\n";
+        O << TAI->getData32bitsDirective() << unsigned(DoubleToBits(Val) >> 32)
+          << "\t" << TAI->getCommentString()
+          << " double most significant word " << Val << "\n";
+      }
+      return;
+    } else {
+      O << TAI->getData32bitsDirective() << FloatToBits(Val)
+        << "\t" << TAI->getCommentString() << " float " << Val << "\n";
+      return;
+    }
+  } else if (CV->getType() == Type::Int64Ty) {
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+      uint64_t Val = CI->getZExtValue();
+
+      if (TAI->getData64bitsDirective())
+        O << TAI->getData64bitsDirective() << Val << "\n";
+      else if (TD->isBigEndian()) {
+        O << TAI->getData32bitsDirective() << unsigned(Val >> 32)
+          << "\t" << TAI->getCommentString()
+          << " Double-word most significant word " << Val << "\n";
+        O << TAI->getData32bitsDirective() << unsigned(Val)
+          << "\t" << TAI->getCommentString()
+          << " Double-word least significant word " << Val << "\n";
+      } else {
+        O << TAI->getData32bitsDirective() << unsigned(Val)
+          << "\t" << TAI->getCommentString()
+          << " Double-word least significant word " << Val << "\n";
+        O << TAI->getData32bitsDirective() << unsigned(Val >> 32)
+          << "\t" << TAI->getCommentString()
+          << " Double-word most significant word " << Val << "\n";
+      }
+      return;
+    }
+  } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CV)) {
+    const VectorType *PTy = CP->getType();
+    
+    for (unsigned I = 0, E = PTy->getNumElements(); I < E; ++I)
+      EmitGlobalConstant(CP->getOperand(I));
+    
+    return;
+  }
+
+  const Type *type = CV->getType();
+  printDataDirective(type);
+  EmitConstantValueOnly(CV);
+  O << "\n";
+}
+
+void
+AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
+  // Target doesn't support this yet!
+  abort();
+}
+
+/// PrintSpecial - Print information related to the specified machine instr
+/// that is independent of the operand, and may be independent of the instr
+/// itself.  This can be useful for portably encoding the comment character
+/// or other bits of target-specific knowledge into the asmstrings.  The
+/// syntax used is ${:comment}.  Targets can override this to add support
+/// for their own strange codes.
+void AsmPrinter::PrintSpecial(const MachineInstr *MI, const char *Code) {
+  if (!strcmp(Code, "private")) {
+    O << TAI->getPrivateGlobalPrefix();
+  } else if (!strcmp(Code, "comment")) {
+    O << TAI->getCommentString();
+  } else if (!strcmp(Code, "uid")) {
+    // Assign a unique ID to this machine instruction.
+    static const MachineInstr *LastMI = 0;
+    static const Function *F = 0;
+    static unsigned Counter = 0U-1;
+
+    // Comparing the address of MI isn't sufficient, because machineinstrs may
+    // be allocated to the same address across functions.
+    const Function *ThisF = MI->getParent()->getParent()->getFunction();
+    
+    // If this is a new machine instruction, bump the counter.
+    if (LastMI != MI || F != ThisF) {
+      ++Counter;
+      LastMI = MI;
+      F = ThisF;
+    }
+    O << Counter;
+  } else {
+    cerr << "Unknown special formatter '" << Code
+         << "' for machine instr: " << *MI;
+    exit(1);
+  }    
+}
+
+
+/// printInlineAsm - This method formats and prints the specified machine
+/// instruction that is an inline asm.
+void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
+  unsigned NumOperands = MI->getNumOperands();
+  
+  // Count the number of register definitions.
+  unsigned NumDefs = 0;
+  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
+       ++NumDefs)
+    assert(NumDefs != NumOperands-1 && "No asm string?");
+  
+  assert(MI->getOperand(NumDefs).isExternalSymbol() && "No asm string?");
+
+  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
+  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
+
+  // If this asmstr is empty, don't bother printing the #APP/#NOAPP markers.
+  if (AsmStr[0] == 0) {
+    O << "\n";  // Tab already printed, avoid double indenting next instr.
+    return;
+  }
+  
+  O << TAI->getInlineAsmStart() << "\n\t";
+
+  // The variant of the current asmprinter.
+  int AsmPrinterVariant = TAI->getAssemblerDialect();
+
+  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
+  const char *LastEmitted = AsmStr; // One past the last character emitted.
+  
+  while (*LastEmitted) {
+    switch (*LastEmitted) {
+    default: {
+      // Not a special case, emit the string section literally.
+      const char *LiteralEnd = LastEmitted+1;
+      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
+             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
+        ++LiteralEnd;
+      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
+        O.write(LastEmitted, LiteralEnd-LastEmitted);
+      LastEmitted = LiteralEnd;
+      break;
+    }
+    case '\n':
+      ++LastEmitted;   // Consume newline character.
+      O << "\n";       // Indent code with newline.
+      break;
+    case '$': {
+      ++LastEmitted;   // Consume '$' character.
+      bool Done = true;
+
+      // Handle escapes.
+      switch (*LastEmitted) {
+      default: Done = false; break;
+      case '$':     // $$ -> $
+        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
+          O << '$';
+        ++LastEmitted;  // Consume second '$' character.
+        break;
+      case '(':             // $( -> same as GCC's { character.
+        ++LastEmitted;      // Consume '(' character.
+        if (CurVariant != -1) {
+          cerr << "Nested variants found in inline asm string: '"
+               << AsmStr << "'\n";
+          exit(1);
+        }
+        CurVariant = 0;     // We're in the first variant now.
+        break;
+      case '|':
+        ++LastEmitted;  // consume '|' character.
+        if (CurVariant == -1) {
+          cerr << "Found '|' character outside of variant in inline asm "
+               << "string: '" << AsmStr << "'\n";
+          exit(1);
+        }
+        ++CurVariant;   // We're in the next variant.
+        break;
+      case ')':         // $) -> same as GCC's } char.
+        ++LastEmitted;  // consume ')' character.
+        if (CurVariant == -1) {
+          cerr << "Found '}' character outside of variant in inline asm "
+               << "string: '" << AsmStr << "'\n";
+          exit(1);
+        }
+        CurVariant = -1;
+        break;
+      }
+      if (Done) break;
+      
+      bool HasCurlyBraces = false;
+      if (*LastEmitted == '{') {     // ${variable}
+        ++LastEmitted;               // Consume '{' character.
+        HasCurlyBraces = true;
+      }
+      
+      const char *IDStart = LastEmitted;
+      char *IDEnd;
+      errno = 0;
+      long Val = strtol(IDStart, &IDEnd, 10); // We only accept numbers for IDs.
+      if (!isdigit(*IDStart) || (Val == 0 && errno == EINVAL)) {
+        cerr << "Bad $ operand number in inline asm string: '" 
+             << AsmStr << "'\n";
+        exit(1);
+      }
+      LastEmitted = IDEnd;
+      
+      char Modifier[2] = { 0, 0 };
+      
+      if (HasCurlyBraces) {
+        // If we have curly braces, check for a modifier character.  This
+        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
+        if (*LastEmitted == ':') {
+          ++LastEmitted;    // Consume ':' character.
+          if (*LastEmitted == 0) {
+            cerr << "Bad ${:} expression in inline asm string: '" 
+                 << AsmStr << "'\n";
+            exit(1);
+          }
+          
+          Modifier[0] = *LastEmitted;
+          ++LastEmitted;    // Consume modifier character.
+        }
+        
+        if (*LastEmitted != '}') {
+          cerr << "Bad ${} expression in inline asm string: '" 
+               << AsmStr << "'\n";
+          exit(1);
+        }
+        ++LastEmitted;    // Consume '}' character.
+      }
+      
+      if ((unsigned)Val >= NumOperands-1) {
+        cerr << "Invalid $ operand number in inline asm string: '" 
+             << AsmStr << "'\n";
+        exit(1);
+      }
+      
+      // Okay, we finally have a value number.  Ask the target to print this
+      // operand!
+      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
+        unsigned OpNo = 1;
+
+        bool Error = false;
+
+        // Scan to find the machine operand number for the operand.
+        for (; Val; --Val) {
+          if (OpNo >= MI->getNumOperands()) break;
+          unsigned OpFlags = MI->getOperand(OpNo).getImmedValue();
+          OpNo += (OpFlags >> 3) + 1;
+        }
+
+        if (OpNo >= MI->getNumOperands()) {
+          Error = true;
+        } else {
+          unsigned OpFlags = MI->getOperand(OpNo).getImmedValue();
+          ++OpNo;  // Skip over the ID number.
+
+          AsmPrinter *AP = const_cast<AsmPrinter*>(this);
+          if ((OpFlags & 7) == 4 /*ADDR MODE*/) {
+            Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
+                                              Modifier[0] ? Modifier : 0);
+          } else {
+            Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
+                                        Modifier[0] ? Modifier : 0);
+          }
+        }
+        if (Error) {
+          cerr << "Invalid operand found in inline asm: '"
+               << AsmStr << "'\n";
+          MI->dump();
+          exit(1);
+        }
+      }
+      break;
+    }
+    }
+  }
+  O << "\n\t" << TAI->getInlineAsmEnd() << "\n";
+}
+
+/// printLabel - This method prints a local label used by debug and
+/// exception handling tables.
+void AsmPrinter::printLabel(const MachineInstr *MI) const {
+  O << "\n"
+    << TAI->getPrivateGlobalPrefix()
+    << "label"
+    << MI->getOperand(0).getImmedValue()
+    << ":\n";
+}
+
+/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
+/// instruction, using the specified assembler variant.  Targets should
+/// overried this to format as appropriate.
+bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
+                                 unsigned AsmVariant, const char *ExtraCode) {
+  // Target doesn't support this yet!
+  return true;
+}
+
+bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
+                                       unsigned AsmVariant,
+                                       const char *ExtraCode) {
+  // Target doesn't support this yet!
+  return true;
+}
+
+/// printBasicBlockLabel - This method prints the label for the specified
+/// MachineBasicBlock
+void AsmPrinter::printBasicBlockLabel(const MachineBasicBlock *MBB,
+                                      bool printColon,
+                                      bool printComment) const {
+  O << TAI->getPrivateGlobalPrefix() << "BB" << FunctionNumber << "_"
+    << MBB->getNumber();
+  if (printColon)
+    O << ':';
+  if (printComment && MBB->getBasicBlock())
+    O << '\t' << TAI->getCommentString() << MBB->getBasicBlock()->getName();
+}
+
+/// printSetLabel - This method prints a set label for the specified
+/// MachineBasicBlock
+void AsmPrinter::printSetLabel(unsigned uid, 
+                               const MachineBasicBlock *MBB) const {
+  if (!TAI->getSetDirective())
+    return;
+  
+  O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
+    << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
+  printBasicBlockLabel(MBB, false, false);
+  O << '-' << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() 
+    << '_' << uid << '\n';
+}
+
+void AsmPrinter::printSetLabel(unsigned uid, unsigned uid2,
+                               const MachineBasicBlock *MBB) const {
+  if (!TAI->getSetDirective())
+    return;
+  
+  O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
+    << getFunctionNumber() << '_' << uid << '_' << uid2
+    << "_set_" << MBB->getNumber() << ',';
+  printBasicBlockLabel(MBB, false, false);
+  O << '-' << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() 
+    << '_' << uid << '_' << uid2 << '\n';
+}
+
+/// printDataDirective - This method prints the asm directive for the
+/// specified type.
+void AsmPrinter::printDataDirective(const Type *type) {
+  const TargetData *TD = TM.getTargetData();
+  switch (type->getTypeID()) {
+  case Type::IntegerTyID: {
+    unsigned BitWidth = cast<IntegerType>(type)->getBitWidth();
+    if (BitWidth <= 8)
+      O << TAI->getData8bitsDirective();
+    else if (BitWidth <= 16)
+      O << TAI->getData16bitsDirective();
+    else if (BitWidth <= 32)
+      O << TAI->getData32bitsDirective();
+    else if (BitWidth <= 64) {
+      assert(TAI->getData64bitsDirective() &&
+             "Target cannot handle 64-bit constant exprs!");
+      O << TAI->getData64bitsDirective();
+    }
+    break;
+  }
+  case Type::PointerTyID:
+    if (TD->getPointerSize() == 8) {
+      assert(TAI->getData64bitsDirective() &&
+             "Target cannot handle 64-bit pointer exprs!");
+      O << TAI->getData64bitsDirective();
+    } else {
+      O << TAI->getData32bitsDirective();
+    }
+    break;
+  case Type::FloatTyID: case Type::DoubleTyID:
+    assert (0 && "Should have already output floating point constant.");
+  default:
+    assert (0 && "Can't handle printing this type of thing");
+    break;
+  }
+}
+