llvm-6502/lib/VMCore/SymbolTable.cpp
Reid Spencer 5cbf985dcb For PR1136: Rename GlobalVariable::isExternal as isDeclaration to avoid
confusion with external linkage types.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33663 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-30 20:08:39 +00:00

337 lines
11 KiB
C++

//===-- 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 &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->isDeclaration() || NewGV->isDeclaration()) &&
"Two planes folded together with overlapping value names!");
// Make sure that ExistGV is the one we want to keep!
if (!NewGV->isDeclaration())
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);
// Update NewGV's name, we're about the remove it from the symbol
// table.
NewGV->Name = "";
// 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
DOUT << "Removing type " << OldType->getDescription() << "\n";
#endif
OldType->removeAbstractTypeUser(this);
// Remove the plane that is no longer used
pmap.erase(PI);
}
}
// 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);
}
static void DumpVal(const std::pair<const std::string, Value *> &V) {
DOUT << " '" << V.first << "' = ";
V.second->dump();
DOUT << "\n";
}
static void DumpPlane(const std::pair<const Type *,
std::map<const std::string, Value *> >&P){
P.first->dump();
DOUT << "\n";
for_each(P.second.begin(), P.second.end(), DumpVal);
}
void SymbolTable::dump() const {
DOUT << "Symbol table dump:\n Plane:";
for_each(pmap.begin(), pmap.end(), DumpPlane);
}
// vim: sw=2 ai