llvm/lib/VMCore/SymbolTable.cpp
Reid Spencer 78d033e086 For PR411:
Take an incremental step towards type plane elimination. This change
separates types from values in the symbol tables by finally making use
of the TypeSymbolTable class. This yields more natural interfaces for
dealing with types and unclutters the SymbolTable class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32956 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-06 07:24:44 +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->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);
// 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