llvm-project/llvm/lib/VMCore/SymbolTable.cpp

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2001-06-07 04:29:01 +08:00
//===-- SymbolTable.cpp - Implement the SymbolTable class -------------------=//
//
// This file implements the SymbolTable class for the VMCore library.
//
//===----------------------------------------------------------------------===//
#include "llvm/SymbolTable.h"
#include "llvm/InstrTypes.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Method.h"
#include "Support/StringExtras.h"
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#define DEBUG_SYMBOL_TABLE 0
#define DEBUG_ABSTYPE 0
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SymbolTable::~SymbolTable() {
// Drop all abstract type references in the type plane...
iterator TyPlane = find(Type::TypeTy);
if (TyPlane != end()) {
VarMap &TyP = TyPlane->second;
for (VarMap::iterator I = TyP.begin(), E = TyP.end(); I != E; ++I) {
const Type *Ty = cast<const Type>(I->second);
if (Ty->isAbstract()) // If abstract, drop the reference...
cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
}
}
// TODO: FIXME: BIG ONE: This doesn't unreference abstract types for the planes
// that could still have entries!
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#ifndef NDEBUG // Only do this in -g mode...
bool LeftoverValues = true;
for (iterator i = begin(); i != end(); ++i) {
for (type_iterator I = i->second.begin(); I != i->second.end(); ++I)
if (!isa<Constant>(I->second) && !isa<Type>(I->second)) {
cerr << "Value still in symbol table! Type = '"
<< i->first->getDescription() << "' Name = '" << I->first << "'\n";
LeftoverValues = false;
}
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}
assert(LeftoverValues && "Values remain in symbol table!");
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#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.
//
string SymbolTable::getUniqueName(const Type *Ty, const string &BaseName) {
iterator I = find(Ty);
if (I == end()) return BaseName;
string TryName = BaseName;
unsigned Counter = 0;
type_iterator End = I->second.end();
while (I->second.find(TryName) != End) // Loop until we find unoccupied
TryName = BaseName + utostr(++Counter); // Name in the symbol table
return TryName;
}
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// lookup - Returns null on failure...
Value *SymbolTable::lookup(const Type *Ty, const string &Name) {
iterator I = find(Ty);
if (I != end()) { // We have symbols in that plane...
type_iterator J = I->second.find(Name);
if (J != I->second.end()) // and the name is in our hash table...
return J->second;
}
return ParentSymTab ? ParentSymTab->lookup(Ty, Name) : 0;
}
void SymbolTable::remove(Value *N) {
assert(N->hasName() && "Value doesn't have name!");
iterator I = find(N->getType());
removeEntry(I, I->second.find(N->getName()));
}
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// removeEntry - Remove a value from the symbol table...
//
Value *SymbolTable::removeEntry(iterator Plane, type_iterator Entry) {
if (InternallyInconsistent) return 0;
assert(Plane != super::end() &&
Entry != Plane->second.end() && "Invalid entry to remove!");
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Value *Result = Entry->second;
const Type *Ty = Result->getType();
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#if DEBUG_SYMBOL_TABLE
cerr << this << " Removing Value: " << Result->getName() << endl;
#endif
// Remove the value from the plane...
Plane->second.erase(Entry);
// If the plane is empty, remove it now!
if (Plane->second.empty()) {
// If the plane represented an abstract type that we were interested in,
// unlink ourselves from this plane.
//
if (Plane->first->isAbstract()) {
#if DEBUG_ABSTYPE
cerr << "Plane Empty: Removing type: " << Plane->first->getDescription()
<< endl;
#endif
cast<DerivedType>(Plane->first)->removeAbstractTypeUser(this);
}
erase(Plane);
}
// If we are removing an abstract type, remove the symbol table from it's use
// list...
if (Ty == Type::TypeTy) {
const Type *T = cast<const Type>(Result);
if (T->isAbstract()) {
#if DEBUG_ABSTYPE
cerr << "Removing abs type from symtab" << T->getDescription() << endl;
#endif
cast<DerivedType>(T)->removeAbstractTypeUser(this);
}
}
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return Result;
}
// insertEntry - Insert a value into the symbol table with the specified
// name...
//
void SymbolTable::insertEntry(const string &Name, const Type *VTy, Value *V) {
// Check to see if there is a naming conflict. If so, rename this value!
if (lookup(VTy, Name)) {
string UniqueName = getUniqueName(VTy, Name);
InternallyInconsistent = true;
V->setName(UniqueName, this);
InternallyInconsistent = false;
return;
}
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#if DEBUG_SYMBOL_TABLE
cerr << this << " Inserting definition: " << Name << ": "
<< VTy->getDescription() << endl;
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#endif
iterator I = find(VTy);
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if (I == end()) { // Not in collection yet... insert dummy entry
// Insert a new empty element. I points to the new elements.
I = super::insert(make_pair(VTy, VarMap())).first;
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assert(I != end() && "How did insert fail?");
// 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
cerr << "Added abstract type value: " << VTy->getDescription() << endl;
#endif
}
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}
I->second.insert(make_pair(Name, V));
// If we are adding an abstract type, add the symbol table to it's use list.
if (VTy == Type::TypeTy) {
const Type *T = cast<const Type>(V);
if (T->isAbstract()) {
cast<DerivedType>(T)->addAbstractTypeUser(this);
#if DEBUG_ABSTYPE
cerr << "Added abstract type to ST: " << T->getDescription() << endl;
#endif
}
}
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}
// This function is called when one of the types in the type plane are refined
void SymbolTable::refineAbstractType(const DerivedType *OldType,
const Type *NewType) {
if (OldType == NewType && OldType->isAbstract())
return; // Noop, don't waste time dinking around
// Search to see if we have any values of the type oldtype. If so, we need to
// move them into the newtype plane...
iterator TPI = find(OldType);
if (OldType != NewType && TPI != end()) {
// Get a handle to the new type plane...
iterator NewTypeIt = find(NewType);
if (NewTypeIt == super::end()) { // If no plane exists, add one
NewTypeIt = super::insert(make_pair(NewType, VarMap())).first;
if (NewType->isAbstract()) {
cast<DerivedType>(NewType)->addAbstractTypeUser(this);
#if DEBUG_ABSTYPE
cerr << "[Added] refined to abstype: "<<NewType->getDescription()<<endl;
#endif
}
}
VarMap &NewPlane = NewTypeIt->second;
VarMap &OldPlane = TPI->second;
while (!OldPlane.empty()) {
pair<const string, Value*> V = *OldPlane.begin();
// Check to see if there is already a value in the symbol table that this
// would collide with.
type_iterator TI = NewPlane.find(V.first);
if (TI != NewPlane.end() && TI->second == V.second) {
// No action
} else if (TI != NewPlane.end()) {
// The only thing we are allowing for now is two method prototypes being
// folded into one.
//
Method *ExistM = dyn_cast<Method>(TI->second);
Method *NewM = dyn_cast<Method>(V.second);
if (ExistM && NewM && ExistM->isExternal() && NewM->isExternal()) {
// Ok we have two external methods. Make all uses of the new one
// use the old one...
//
NewM->replaceAllUsesWith(ExistM);
// Now we just convert it to an unnamed method... which won't get
// added to our symbol table. The problem is that if we call
// setName on the method that it will try to remove itself from
// the symbol table and die... because it's not in the symtab
// right now. To fix this, we have an internally consistent flag
// that turns remove into a noop. Thus the name will get null'd
// out, but the symbol table won't get upset.
//
InternallyInconsistent = true;
// Remove newM from the symtab
NewM->setName("");
InternallyInconsistent = false;
// Now we can remove this method from the module entirely...
NewM->getParent()->getMethodList().remove(NewM);
delete NewM;
} else {
assert(0 && "Two ploanes folded together with overlapping "
"value names!");
}
} else {
insertEntry(V.first, NewType, V.second);
}
// Remove the item from the old type plane
OldPlane.erase(OldPlane.begin());
}
// Ok, now we are not referencing the type anymore... take me off your user
// list please!
#if DEBUG_ABSTYPE
cerr << "Removing type " << OldType->getDescription() << endl;
#endif
OldType->removeAbstractTypeUser(this);
// Remove the plane that is no longer used
erase(TPI);
} else if (TPI != end()) {
assert(OldType == NewType);
#if DEBUG_ABSTYPE
cerr << "Removing SELF type " << OldType->getDescription() << endl;
#endif
OldType->removeAbstractTypeUser(this);
}
TPI = find(Type::TypeTy);
assert(TPI != end() &&"Type plane not in symbol table but we contain types!");
// Loop over all of the types in the symbol table, replacing any references to
// OldType with references to NewType. Note that there may be multiple
// occurances, and although we only need to remove one at a time, it's faster
// to remove them all in one pass.
//
VarMap &TyPlane = TPI->second;
for (VarMap::iterator I = TyPlane.begin(), E = TyPlane.end(); I != E; ++I)
if (I->second == (Value*)OldType) { // FIXME when Types aren't const.
#if DEBUG_ABSTYPE
cerr << "Removing type " << OldType->getDescription() << endl;
#endif
OldType->removeAbstractTypeUser(this);
I->second = (Value*)NewType; // TODO FIXME when types aren't const
if (NewType->isAbstract()) {
#if DEBUG_ABSTYPE
cerr << "Added type " << NewType->getDescription() << endl;
#endif
cast<const DerivedType>(NewType)->addAbstractTypeUser(this);
}
}
}
#ifndef NDEBUG
#include "llvm/Assembly/Writer.h"
#include <algorithm>
static void DumpVal(const pair<const string, Value *> &V) {
cout << " '" << V.first << "' = " << V.second << endl;
}
static void DumpPlane(const pair<const Type *, map<const string, Value *> >&P) {
cout << " Plane: " << P.first << endl;
for_each(P.second.begin(), P.second.end(), DumpVal);
}
void SymbolTable::dump() const {
cout << "Symbol table dump:\n";
for_each(begin(), end(), DumpPlane);
if (ParentSymTab) {
cout << "Parent ";
ParentSymTab->dump();
}
}
#endif