llvm/lib/VMCore/Function.cpp

//===-- Function.cpp - Implement the Global object classes ----------------===//
// 
//                     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 Function & GlobalVariable classes for the VMCore
// library.
//
//===----------------------------------------------------------------------===//

#include "llvm/Module.h"
#include "llvm/Constant.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iOther.h"
#include "llvm/Intrinsics.h"
#include "Support/LeakDetector.h"
#include "SymbolTableListTraitsImpl.h"
using namespace llvm;

BasicBlock *ilist_traits<BasicBlock>::createNode() {
  BasicBlock *Ret = new BasicBlock();
  // This should not be garbage monitored.
  LeakDetector::removeGarbageObject(Ret);
  return Ret;
}

iplist<BasicBlock> &ilist_traits<BasicBlock>::getList(Function *F) {
  return F->getBasicBlockList();
}

Argument *ilist_traits<Argument>::createNode() {
  Argument *Ret = new Argument(Type::IntTy);
  // This should not be garbage monitored.
  LeakDetector::removeGarbageObject(Ret);
  return Ret;
}

iplist<Argument> &ilist_traits<Argument>::getList(Function *F) {
  return F->getArgumentList();
}

// Explicit instantiations of SymbolTableListTraits since some of the methods
// are not in the public header file...
template class SymbolTableListTraits<Argument, Function, Function>;
template class SymbolTableListTraits<BasicBlock, Function, Function>;

//===----------------------------------------------------------------------===//
// Argument Implementation
//===----------------------------------------------------------------------===//

Argument::Argument(const Type *Ty, const std::string &Name, Function *Par) 
  : Value(Ty, Value::ArgumentVal, Name) {
  Parent = 0;

  // Make sure that we get added to a function
  LeakDetector::addGarbageObject(this);

  if (Par)
    Par->getArgumentList().push_back(this);
}


// Specialize setName to take care of symbol table majik
void Argument::setName(const std::string &name, SymbolTable *ST) {
  Function *P;
  assert((ST == 0 || (!getParent() || ST == &getParent()->getSymbolTable())) &&
	 "Invalid symtab argument!");
  if ((P = getParent()) && hasName()) P->getSymbolTable().remove(this);
  Value::setName(name);
  if (P && hasName()) P->getSymbolTable().insert(this);
}

void Argument::setParent(Function *parent) {
  if (getParent())
    LeakDetector::addGarbageObject(this);
  Parent = parent;
  if (getParent())
    LeakDetector::removeGarbageObject(this);
}

static bool removeDeadConstantUsers(Constant *C) {
  while (!C->use_empty()) {
    if (Constant *C = dyn_cast<Constant>(C->use_back())) {
      if (!removeDeadConstantUsers(C))
        return false;  // Constant wasn't dead.
    } else {
      return false;    // Nonconstant user of the global.
    }
  }

  C->destroyConstant();
  return true;
}


/// removeDeadConstantUsers - If there are any dead constant users dangling
/// off of this global value, remove them.  This method is useful for clients
/// that want to check to see if a global is unused, but don't want to deal
/// with potentially dead constants hanging off of the globals.
///
/// This function returns true if the global value is now dead.  If all 
/// users of this global are not dead, this method may return false and
/// leave some of them around.
bool GlobalValue::removeDeadConstantUsers() {
  while (!use_empty()) {
    if (Constant *C = dyn_cast<Constant>(use_back())) {
      if (!::removeDeadConstantUsers(C))
        return false;  // Constant wasn't dead.
    } else {
      return false;    // Nonconstant user of the global.
    }
  }
  return true;
}


//===----------------------------------------------------------------------===//
// Function Implementation
//===----------------------------------------------------------------------===//

Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
                   const std::string &name, Module *ParentModule)
  : GlobalValue(PointerType::get(Ty), Value::FunctionVal, Linkage, name) {
  BasicBlocks.setItemParent(this);
  BasicBlocks.setParent(this);
  ArgumentList.setItemParent(this);
  ArgumentList.setParent(this);
  SymTab = new SymbolTable();

  assert((getReturnType()->isFirstClassType() ||getReturnType() == Type::VoidTy)
         && "LLVM functions cannot return aggregate values!");

  // Create the arguments vector, all arguments start out unnamed.
  for (unsigned i = 0, e = Ty->getNumParams(); i != e; ++i) {
    assert(Ty->getParamType(i) != Type::VoidTy &&
           "Cannot have void typed arguments!");
    ArgumentList.push_back(new Argument(Ty->getParamType(i)));
  }

  // Make sure that we get added to a function
  LeakDetector::addGarbageObject(this);

  if (ParentModule)
    ParentModule->getFunctionList().push_back(this);
}

Function::~Function() {
  dropAllReferences();    // After this it is safe to delete instructions.

  // Delete all of the method arguments and unlink from symbol table...
  ArgumentList.clear();
  ArgumentList.setParent(0);
  delete SymTab;
}

// Specialize setName to take care of symbol table majik
void Function::setName(const std::string &name, SymbolTable *ST) {
  Module *P;
  assert((ST == 0 || (!getParent() || ST == &getParent()->getSymbolTable())) &&
	 "Invalid symtab argument!");
  if ((P = getParent()) && hasName()) P->getSymbolTable().remove(this);
  Value::setName(name);
  if (P && hasName()) P->getSymbolTable().insert(this);
}

void Function::setParent(Module *parent) {
  if (getParent())
    LeakDetector::addGarbageObject(this);
  Parent = parent;
  if (getParent())
    LeakDetector::removeGarbageObject(this);
}

const FunctionType *Function::getFunctionType() const {
  return cast<FunctionType>(getType()->getElementType());
}

const Type *Function::getReturnType() const { 
  return getFunctionType()->getReturnType();
}

// dropAllReferences() - This function causes all the subinstructions to "let
// go" of all references that they are maintaining.  This allows one to
// 'delete' a whole class at a time, even though there may be circular
// references... first all references are dropped, and all use counts go to
// zero.  Then everything is deleted for real.  Note that no operations are
// valid on an object that has "dropped all references", except operator 
// delete.
//
void Function::dropAllReferences() {
  for (iterator I = begin(), E = end(); I != E; ++I)
    I->dropAllReferences();
  BasicBlocks.clear();    // Delete all basic blocks...
}

/// getIntrinsicID - This method returns the ID number of the specified
/// function, or Intrinsic::not_intrinsic if the function is not an
/// intrinsic, or if the pointer is null.  This value is always defined to be
/// zero to allow easy checking for whether a function is intrinsic or not.  The
/// particular intrinsic functions which correspond to this value are defined in
/// llvm/Intrinsics.h.
///
unsigned Function::getIntrinsicID() const {
  if (getName().size() < 5 || getName()[4] != '.' || getName()[0] != 'l' ||
      getName()[1] != 'l' || getName()[2] != 'v' || getName()[3] != 'm')
    return 0;  // All intrinsics start with 'llvm.'

  assert(getName().size() != 5 && "'llvm.' is an invalid intrinsic name!");
  
  // a table of all Alpha intrinsic functions
  struct {
   std::string name;  // The name of the intrinsic 
   unsigned id;       // Its ID number
  } alpha_intrinsics[] = {
     { "llvm.alpha.ctlz",      Intrinsic::alpha_ctlz },
     { "llvm.alpha.cttz",      Intrinsic::alpha_cttz },
     { "llvm.alpha.ctpop",     Intrinsic::alpha_ctpop },
     { "llvm.alpha.umulh",     Intrinsic::alpha_umulh },
     { "llvm.alpha.vecop",     Intrinsic::alpha_vecop },
     { "llvm.alpha.pup",       Intrinsic::alpha_pup },
     { "llvm.alpha.bytezap",   Intrinsic::alpha_bytezap },
     { "llvm.alpha.bytemanip", Intrinsic::alpha_bytemanip },
     { "llvm.alpha.dfp_bop",   Intrinsic::alpha_dfpbop }, 
     { "llvm.alpha.dfp_uop",   Intrinsic::alpha_dfpuop },
     { "llvm.alpha.unordered", Intrinsic::alpha_unordered },
     { "llvm.alpha.uqtodfp",   Intrinsic::alpha_uqtodfp },
     { "llvm.alpha.uqtosfp",   Intrinsic::alpha_uqtosfp },
     { "llvm.alpha.dfptosq",   Intrinsic::alpha_dfptosq },
     { "llvm.alpha.sfptosq",   Intrinsic::alpha_sfptosq },
  };
  const unsigned num_alpha_intrinsics = 
                 sizeof(alpha_intrinsics) / sizeof(*alpha_intrinsics);

  switch (getName()[5]) {
  case 'a':
    if (getName().size() > 11 &&
        std::string(getName().begin()+4, getName().begin()+11) == ".alpha.")
      for (unsigned i = 0; i < num_alpha_intrinsics; ++i)
        if (getName() == alpha_intrinsics[i].name)
          return alpha_intrinsics[i].id;
    break;
  case 'd':
    if (getName() == "llvm.dbg.stoppoint")   return Intrinsic::dbg_stoppoint;
    if (getName() == "llvm.dbg.region.start")return Intrinsic::dbg_region_start;
    if (getName() == "llvm.dbg.region.end")  return Intrinsic::dbg_region_end;
    if (getName() == "llvm.dbg.func.start")  return Intrinsic::dbg_func_start;
    if (getName() == "llvm.dbg.declare")     return Intrinsic::dbg_declare;
    break;
  case 'f':
    if (getName() == "llvm.frameaddress")  return Intrinsic::frameaddress;
    break;
  case 'g':
    if (getName() == "llvm.gcwrite") return Intrinsic::gcwrite;
    if (getName() == "llvm.gcread")  return Intrinsic::gcread;
    if (getName() == "llvm.gcroot")  return Intrinsic::gcroot;
    break;
  case 'i':
    if (getName() == "llvm.isunordered") return Intrinsic::isunordered;
    break;
  case 'l':
    if (getName() == "llvm.longjmp")  return Intrinsic::longjmp;
    break;
  case 'm':
    if (getName() == "llvm.memcpy")  return Intrinsic::memcpy;
    if (getName() == "llvm.memmove")  return Intrinsic::memmove;
    if (getName() == "llvm.memset")  return Intrinsic::memset;
    break;
  case 'r':
    if (getName() == "llvm.returnaddress")  return Intrinsic::returnaddress;
    if (getName() == "llvm.readport")       return Intrinsic::readport;
    if (getName() == "llvm.readio")         return Intrinsic::readio;
    break;
  case 's':
    if (getName() == "llvm.setjmp")     return Intrinsic::setjmp;
    if (getName() == "llvm.sigsetjmp")  return Intrinsic::sigsetjmp;
    if (getName() == "llvm.siglongjmp") return Intrinsic::siglongjmp;
    break;
  case 'v':
    if (getName() == "llvm.va_copy")  return Intrinsic::vacopy;
    if (getName() == "llvm.va_end")   return Intrinsic::vaend;
    if (getName() == "llvm.va_start") return Intrinsic::vastart;
  case 'w':
    if (getName() == "llvm.writeport") return Intrinsic::writeport;
    if (getName() == "llvm.writeio")   return Intrinsic::writeio;
    break;
  }
  // The "llvm." namespace is reserved!
  assert(0 && "Unknown LLVM intrinsic function!");
  return 0;
}


//===----------------------------------------------------------------------===//
// GlobalVariable Implementation
//===----------------------------------------------------------------------===//

GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link,
			       Constant *Initializer,
			       const std::string &Name, Module *ParentModule)
  : GlobalValue(PointerType::get(Ty), Value::GlobalVariableVal, Link, Name),
    isConstantGlobal(constant) {
  if (Initializer) Operands.push_back(Use((Value*)Initializer, this));

  LeakDetector::addGarbageObject(this);

  if (ParentModule)
    ParentModule->getGlobalList().push_back(this);
}

void GlobalVariable::setParent(Module *parent) {
  if (getParent())
    LeakDetector::addGarbageObject(this);
  Parent = parent;
  if (getParent())
    LeakDetector::removeGarbageObject(this);
}

// Specialize setName to take care of symbol table majik
void GlobalVariable::setName(const std::string &name, SymbolTable *ST) {
  Module *P;
  assert((ST == 0 || (!getParent() || ST == &getParent()->getSymbolTable())) &&
	 "Invalid symtab argument!");
  if ((P = getParent()) && hasName()) P->getSymbolTable().remove(this);
  Value::setName(name);
  if (P && hasName()) P->getSymbolTable().insert(this);
}