path: root/lib/VMCore/SymbolTable.cpp

//===-- SymbolTable.cpp - Implement the SymbolTable class -----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and revised by Reid
// Spencer. It is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SymbolTable class for the VMCore library.
//
//===----------------------------------------------------------------------===//

#include "llvm/SymbolTable.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
using namespace llvm;

#define DEBUG_SYMBOL_TABLE 0
#define DEBUG_ABSTYPE 0

SymbolTable::~SymbolTable() {
 // TODO: FIXME: BIG ONE: This doesn't unreference abstract types for the
 // planes that could still have entries!

#ifndef NDEBUG   // Only do this in -g mode...
  bool LeftoverValues = true;
  for (plane_iterator PI = pmap.begin(); PI != pmap.end(); ++PI) {
    for (value_iterator VI = PI->second.begin(); VI != PI->second.end(); ++VI)
      if (!isa<Constant>(VI->second) ) {
        DOUT << "Value still in symbol table! Type = '"
             << PI->first->getDescription() << "' Name = '"
             << VI->first << "'\n";
        LeftoverValues = false;
      }
  }

  assert(LeftoverValues && "Values remain in symbol table!");
#endif
}

// getUniqueName - Given a base name, return a string that is either equal to
// it (or derived from it) that does not already occur in the symbol table for
// the specified type.
//
std::string SymbolTable::getUniqueName(const Type *Ty,
                                       const std::string &BaseName) const {
  // Find the plane
  plane_const_iterator PI = pmap.find(Ty);
  if (PI == pmap.end()) return BaseName;

  std::string TryName = BaseName;
  const ValueMap& vmap = PI->second;
  value_const_iterator End = vmap.end();

  // See if the name exists
  while (vmap.find(TryName) != End)            // Loop until we find a free
    TryName = BaseName + utostr(++LastUnique); // name in the symbol table
  return TryName;
}


// lookup a value - Returns null on failure...
Value *SymbolTable::lookup(const Type *Ty, const std::string &Name) const {
  plane_const_iterator PI = pmap.find(Ty);
  if (PI != pmap.end()) {                // We have symbols in that plane.
    value_const_iterator VI = PI->second.find(Name);
    if (VI != PI->second.end())          // and the name is in our hash table.
      return VI->second;
  }
  return 0;
}


/// changeName - Given a value with a non-empty name, remove its existing entry
/// from the symbol table and insert a new one for Name.  This is equivalent to
/// doing "remove(V), V->Name = Name, insert(V)", but is faster, and will not
/// temporarily remove the symbol table plane if V is the last value in the
/// symtab with that name (which could invalidate iterators to that plane).
void SymbolTable::changeName(Value *V, const std::string &name) {
  assert(!V->getName().empty() && !name.empty() && V->getName() != name &&
         "Illegal use of this method!");

  plane_iterator PI = pmap.find(V->getType());
  assert(PI != pmap.end() && "Value doesn't have an entry in this table?");
  ValueMap &VM = PI->second;

  value_iterator VI = VM.find(V->getName());
  assert(VI != VM.end() && "Value does have an entry in this table?");

  // Remove the old entry.
  VM.erase(VI);

  // See if we can insert the new name.
  VI = VM.lower_bound(name);

  // Is there a naming conflict?
  if (VI != VM.end() && VI->first == name) {
    V->Name = getUniqueName(V->getType(), name);
    VM.insert(make_pair(V->Name, V));
  } else {
    V->Name = name;
    VM.insert(VI, make_pair(name, V));
  }
}

// Remove a value
void SymbolTable::remove(Value *N) {
  assert(N->hasName() && "Value doesn't have name!");

  plane_iterator PI = pmap.find(N->getType());
  assert(PI != pmap.end() &&
         "Trying to remove a value that doesn't have a type plane yet!");
  ValueMap &VM = PI->second;
  value_iterator Entry = VM.find(N->getName());
  assert(Entry != VM.end() && "Invalid entry to remove!");

#if DEBUG_SYMBOL_TABLE
  dump();
  DOUT << " Removing Value: " << Entry->second->getName() << "\n";
#endif

  // Remove the value from the plane...
  VM.erase(Entry);

  // If the plane is empty, remove it now!
  if (VM.empty()) {
    // If the plane represented an abstract type that we were interested in,
    // unlink ourselves from this plane.
    //
    if (N->getType()->isAbstract()) {
#if DEBUG_ABSTYPE
      DOUT << "Plane Empty: Removing type: "
           << N->getType()->getDescription() << "\n";
#endif
      cast<DerivedType>(N->getType())->removeAbstractTypeUser(this);
    }

    pmap.erase(PI);
  }
}


// insertEntry - Insert a value into the symbol table with the specified name.
void SymbolTable::insertEntry(const std::string &Name, const Type *VTy,
                              Value *V) {
  plane_iterator PI = pmap.find(VTy);   // Plane iterator
  value_iterator VI;                    // Actual value iterator
  ValueMap *VM;                         // The plane we care about.

#if DEBUG_SYMBOL_TABLE
  dump();
  DOUT << " Inserting definition: " << Name << ": "
       << VTy->getDescription() << "\n";
#endif

  if (PI == pmap.end()) {      // Not in collection yet... insert dummy entry
    // Insert a new empty element.  I points to the new elements.
    VM = &pmap.insert(make_pair(VTy, ValueMap())).first->second;
    VI = VM->end();

    // Check to see if the type is abstract.  If so, it might be refined in the
    // future, which would cause the plane of the old type to get merged into
    // a new type plane.
    //
    if (VTy->isAbstract()) {
      cast<DerivedType>(VTy)->addAbstractTypeUser(this);
#if DEBUG_ABSTYPE
      DOUT << "Added abstract type value: " << VTy->getDescription()
           << "\n";
#endif
    }

  } else {
    // Check to see if there is a naming conflict.  If so, rename this value!
    VM = &PI->second;
    VI = VM->lower_bound(Name);
    if (VI != VM->end() && VI->first == Name) {
      V->Name = getUniqueName(VTy, Name);
      VM->insert(make_pair(V->Name, V));
      return;
    }
  }

  VM->insert(VI, make_pair(Name, V));
}



// Strip the symbol table of its names.
bool SymbolTable::strip() {
  bool RemovedSymbol = false;
  for (plane_iterator I = pmap.begin(); I != pmap.end();) {
    // Removing items from the plane can cause the plane itself to get deleted.
    // If this happens, make sure we incremented our plane iterator already!
    ValueMap &Plane = (I++)->second;
    value_iterator B = Plane.begin(), Bend = Plane.end();
    while (B != Bend) {   // Found nonempty type plane!
      Value *V = B->second;
      ++B;
      if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()) {
        // Set name to "", removing from symbol table!
        V->setName("");
        RemovedSymbol = true;
      }
    }
  }

  return RemovedSymbol;
}


// This function is called when one of the types in the type plane are refined
void SymbolTable::refineAbstractType(const DerivedType *OldType,
                                     const Type *NewType) {

  // Search to see if we have any values of the type Oldtype.  If so, we need to
  // move them into the newtype plane...
  plane_iterator PI = pmap.find(OldType);
  if (PI != pmap.end()) {
    // Get a handle to the new type plane...
    plane_iterator NewTypeIt = pmap.find(NewType);
    if (NewTypeIt == pmap.end()) {      // If no plane exists, add one
      NewTypeIt = pmap.insert(make_pair(NewType, ValueMap())).first;

      if (NewType->isAbstract()) {
        cast<DerivedType>(NewType)->addAbstractTypeUser(this);
#if DEBUG_ABSTYPE
        DOUT << "[Added] refined to abstype: " << NewType->getDescription()
             << "\n";
#endif
      }
    }

    ValueMap &NewPlane = NewTypeIt->second;
    ValueMap