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

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//===-- 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 "Support/StringExtras.h"
#include <algorithm>
using namespace llvm;
#define DEBUG_SYMBOL_TABLE 0
#define DEBUG_ABSTYPE 0
SymbolTable::~SymbolTable() {
// Drop all abstract type references in the type plane...
for (type_iterator TI = tmap.begin(), TE = tmap.end(); TI != TE; ++TI) {
if (TI->second->isAbstract()) // If abstract, drop the reference...
cast<DerivedType>(TI->second)->removeAbstractTypeUser(this);
}
// 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) ) {
std::cerr << "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;
}
// lookup a type by name - returns null on failure
Type* SymbolTable::lookupType( const std::string& Name ) const {
type_const_iterator TI = tmap.find( Name );
if ( TI != tmap.end() )
return TI->second;
return 0;
}
// Remove a value
void SymbolTable::remove(Value *N) {
assert(N->hasName() && "Value doesn't have name!");
assert(!isa<Type>(N) && "Can't remove types through this interface.");
if (InternallyInconsistent) return;
plane_iterator PI = pmap.find(N->getType());
assert(PI != pmap.end() &&
"Trying to remove a value that doesn't have a type plane yet!");
removeEntry(PI, PI->second.find(N->getName()));
}
// removeEntry - Remove a value from the symbol table...
Value *SymbolTable::removeEntry(plane_iterator Plane, value_iterator Entry) {
if (InternallyInconsistent) return 0;
assert(Plane != pmap.end() &&
Entry != Plane->second.end() && "Invalid entry to remove!");
Value *Result = Entry->second;
assert(!isa<Type>(Result) && "Can't remove types through this interface.");
#if DEBUG_SYMBOL_TABLE
dump();
std::cerr << " Removing Value: " << Result->getName() << "\n";
#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
std::cerr << "Plane Empty: Removing type: "
<< Plane->first->getDescription() << "\n";
#endif
cast<DerivedType>(Plane->first)->removeAbstractTypeUser(this);
}
pmap.erase(Plane);
}
return Result;
}
// remove - Remove a type
void SymbolTable::remove(Type* Ty ) {
type_iterator TI = this->type_begin();
type_iterator TE = this->type_end();
// Search for the entry
while ( TI != TE && TI->second != Ty )
++TI;
if ( TI != TE )
this->removeEntry( TI );
}
// removeEntry - Remove a type from the symbol table...
Type* SymbolTable::removeEntry(type_iterator Entry) {
if (InternallyInconsistent) return 0;
assert( Entry != tmap.end() && "Invalid entry to remove!");
Type* Result = Entry->second;
#if DEBUG_SYMBOL_TABLE
dump();
std::cerr << " Removing Value: " << Result->getName() << "\n";
#endif
tmap.erase(Entry);
// If we are removing an abstract type, remove the symbol table from it's use
// list...
if (Result->isAbstract()) {
#if DEBUG_ABSTYPE
std::cerr << "Removing abstract type from symtab" << Result->getDescription()<<"\n";
#endif
cast<DerivedType>(Result)->removeAbstractTypeUser(this);
}
return Result;
}
// insertEntry - Insert a value into the symbol table with the specified name.
void SymbolTable::insertEntry(const std::string &Name, const Type *VTy,
Value *V) {
assert(!isa<Type>(V) && "Can't insert types through this interface.");
// Check to see if there is a naming conflict. If so, rename this value!
if (lookup(VTy, Name)) {
std::string UniqueName = getUniqueName(VTy, Name);
assert(InternallyInconsistent == false && "Infinite loop inserting value!");
InternallyInconsistent = true;
V->setName(UniqueName, this);
InternallyInconsistent = false;
return;
}
#if DEBUG_SYMBOL_TABLE
dump();
std::cerr << " Inserting definition: " << Name << ": "
<< VTy->getDescription() << "\n";
#endif
plane_iterator PI = pmap.find(VTy);
if (PI == pmap.end()) { // Not in collection yet... insert dummy entry
// Insert a new empty element. I points to the new elements.
PI = pmap.insert(make_pair(VTy, ValueMap())).first;
assert(PI != pmap.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
std::cerr << "Added abstract type value: " << VTy->getDescription()
<< "\n";
#endif
}
}
PI->second.insert(make_pair(Name, V));
}
// insertEntry - Insert a value into the symbol table with the specified
// name...
//
void SymbolTable::insertEntry(const std::string& Name, Type* T) {
// Check to see if there is a naming conflict. If so, rename this type!
std::string UniqueName = Name;
if (lookupType(Name))
UniqueName = getUniqueName(T, Name);
#if DEBUG_SYMBOL_TABLE
dump();
std::cerr << " Inserting type: " << UniqueName << ": "
<< T->getDescription() << "\n";
#endif
// Insert the tmap entry
tmap.insert(make_pair(UniqueName, T));
// If we are adding an abstract type, add the symbol table to it's use list.
if (T->isAbstract()) {
cast<DerivedType>(T)->addAbstractTypeUser(this);
#if DEBUG_ABSTYPE
std::cerr << "Added abstract type to ST: " << T->getDescription() << "\n";
#endif
}
}
// Determine how many entries for a given type.
unsigned SymbolTable::type_size(const Type *Ty) const {
plane_const_iterator PI = pmap.find(Ty);
if ( PI == pmap.end() ) return 0;
return PI->second.size();
}
// Get the name of a value
std::string SymbolTable::get_name( const Value* V ) const {
assert(!isa<Type>(V) && "Can't get name of types through this interface.");
value_const_iterator VI = this->value_begin( V->getType() );
value_const_iterator VE = this->value_end( V->getType() );
// Search for the entry
while ( VI != VE && VI->second != V )
++VI;
if ( VI != VE )
return VI->first;
return "";
}
// Get the name of a type
std::string SymbolTable::get_name( const Type* T ) const {
if (tmap.empty()) return ""; // No types at all.
type_const_iterator TI = tmap.begin();
type_const_iterator TE = tmap.end();
// Search for the entry
while (TI != TE && TI->second != T )
++TI;
if (TI != TE) // Must have found an entry!
return TI->first;
return ""; // Must not have found anything...
}
// Strip the symbol table of its names.
bool SymbolTable::strip( void ) {
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;
if (isa<Constant>(V)) {
remove(V);
RemovedSymbol = true;
} else {
if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()){
// Set name to "", removing from symbol table!
V->setName("", this);
RemovedSymbol = true;
}
}
++B;
}
}
for (type_iterator TI = tmap.begin(); TI != tmap.end(); ) {
Type* T = (TI++)->second;
remove(T);
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
std::cerr << "[Added] refined to abstype: " << NewType->getDescription()
<< "\n";
#endif
}
}
ValueMap &NewPlane = NewTypeIt->second;
ValueMap &OldPlane = PI->second;
while (!OldPlane.empty()) {
std::pair<const std::string, Value*> V = *OldPlane.begin();
// Check to see if there is already a value in the symbol table that this
// would collide with.
value_iterator VI = NewPlane.find(V.first);
if (VI != NewPlane.end() && VI->second == V.second) {
// No action
} else if (VI != NewPlane.end()) {
// The only thing we are allowing for now is two external global values
// folded into one.
//
GlobalValue *ExistGV = dyn_cast<GlobalValue>(VI->second);
GlobalValue *NewGV = dyn_cast<GlobalValue>(V.second);
if (ExistGV && NewGV) {
assert((ExistGV->isExternal() || NewGV->isExternal()) &&
"Two planes folded together with overlapping value names!");
// Make sure that ExistGV is the one we want to keep!
if (!NewGV->isExternal())
std::swap(NewGV, ExistGV);
// Ok we have two external global values. Make all uses of the new
// one use the old one...
NewGV->uncheckedReplaceAllUsesWith(ExistGV);
// 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.
//
assert(InternallyInconsistent == false &&
"Symbol table already inconsistent!");
InternallyInconsistent = true;
// Remove newM from the symtab
NewGV->setName("");
InternallyInconsistent = false;
// Now we can remove this global from the module entirely...
Module *M = NewGV->getParent();
if (Function *F = dyn_cast<Function>(NewGV))
M->getFunctionList().remove(F);
else
M->getGlobalList().remove(cast<GlobalVariable>(NewGV));
delete NewGV;
} else {
// If they are not global values, they must be just random values who
// happen to conflict now that types have been resolved. If this is
// the case, reinsert the value into the new plane, allowing it to get
// renamed.
assert(V.second->getType() == NewType &&"Type resolution is broken!");
insert(V.second);
}
} 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
std::cerr << "Removing type " << OldType->getDescription() << "\n";
#endif
OldType->removeAbstractTypeUser(this);
// Remove the plane that is no longer used
pmap.erase(PI);
}
// 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
// occurrences, and although we only need to remove one at a time, it's
// faster to remove them all in one pass.
//
for (type_iterator I = type_begin(), E = type_end(); I != E; ++I) {
if (I->second == (Type*)OldType) { // FIXME when Types aren't const.
#if DEBUG_ABSTYPE
std::cerr << "Removing type " << OldType->getDescription() << "\n";
#endif
OldType->removeAbstractTypeUser(this);
I->second = (Type*)NewType; // TODO FIXME when types aren't const
if (NewType->isAbstract()) {
#if DEBUG_ABSTYPE
std::cerr << "Added type " << NewType->getDescription() << "\n";
#endif
cast<DerivedType>(NewType)->addAbstractTypeUser(this);
}
}
}
}
// Handle situation where type becomes Concreate from Abstract
void SymbolTable::typeBecameConcrete(const DerivedType *AbsTy) {
plane_iterator PI = pmap.find(AbsTy);
// If there are any values in the symbol table of this type, then the type
// plane is a use of the abstract type which must be dropped.
if (PI != pmap.end())
AbsTy->removeAbstractTypeUser(this);
// Loop over all of the types in the symbol table, dropping any abstract
// type user entries for AbsTy which occur because there are names for the
// type.
for (type_iterator TI = type_begin(), TE = type_end(); TI != TE; ++TI)
if (TI->second == (Type*)AbsTy) // FIXME when Types aren't const.
AbsTy->removeAbstractTypeUser(this);
}
static void DumpVal(const std::pair<const std::string, Value *> &V) {
std::cerr << " '" << V.first << "' = ";
V.second->dump();
std::cerr << "\n";
}
static void DumpPlane(const std::pair<const Type *,
std::map<const std::string, Value *> >&P){
P.first->dump();
std::cerr << "\n";
for_each(P.second.begin(), P.second.end(), DumpVal);
}
static void DumpTypes(const std::pair<const std::string, Type*>& T ) {
std::cerr << " '" << T.first << "' = ";
T.second->dump();
std::cerr << "\n";
}
void SymbolTable::dump() const {
std::cerr << "Symbol table dump:\n Plane:";
for_each(pmap.begin(), pmap.end(), DumpPlane);
std::cerr << " Types: ";
for_each(tmap.begin(), tmap.end(), DumpTypes);
}
// vim: sw=2 ai
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