llvm-6502/lib/Bytecode/Writer/SlotCalculator.cpp
Anton Korobeynikov a80e1181b7 Implement review feedback. Aliasees can be either GlobalValue's or
bitcasts of them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36537 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-28 13:45:00 +00:00

391 lines
15 KiB
C++

//===-- SlotCalculator.cpp - Calculate what slots values land in ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a useful analysis step to figure out what numbered slots
// values in a program will land in (keeping track of per plane information).
//
// This is used when writing a file to disk, either in bytecode or assembly.
//
//===----------------------------------------------------------------------===//
#include "SlotCalculator.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/TypeSymbolTable.h"
#include "llvm/Type.h"
#include "llvm/ValueSymbolTable.h"
#include "llvm/ADT/STLExtras.h"
#include <algorithm>
#include <functional>
using namespace llvm;
#ifndef NDEBUG
#include "llvm/Support/Streams.h"
#include "llvm/Support/CommandLine.h"
static cl::opt<bool> SlotCalculatorDebugOption("scdebug",cl::init(false),
cl::desc("Enable SlotCalculator debug output"), cl::Hidden);
#define SC_DEBUG(X) if (SlotCalculatorDebugOption) cerr << X
#else
#define SC_DEBUG(X)
#endif
void SlotCalculator::insertPrimitives() {
// Preload the table with the built-in types. These built-in types are
// inserted first to ensure that they have low integer indices which helps to
// keep bytecode sizes small. Note that the first group of indices must match
// the Type::TypeIDs for the primitive types. After that the integer types are
// added, but the order and value is not critical. What is critical is that
// the indices of these "well known" slot numbers be properly maintained in
// Reader.h which uses them directly to extract values of these types.
SC_DEBUG("Inserting primitive types:\n");
// See WellKnownTypeSlots in Reader.h
getOrCreateTypeSlot(Type::VoidTy ); // 0: VoidTySlot
getOrCreateTypeSlot(Type::FloatTy ); // 1: FloatTySlot
getOrCreateTypeSlot(Type::DoubleTy); // 2: DoubleTySlot
getOrCreateTypeSlot(Type::LabelTy ); // 3: LabelTySlot
assert(TypeMap.size() == Type::FirstDerivedTyID &&"Invalid primitive insert");
// Above here *must* correspond 1:1 with the primitive types.
getOrCreateTypeSlot(Type::Int1Ty ); // 4: Int1TySlot
getOrCreateTypeSlot(Type::Int8Ty ); // 5: Int8TySlot
getOrCreateTypeSlot(Type::Int16Ty ); // 6: Int16TySlot
getOrCreateTypeSlot(Type::Int32Ty ); // 7: Int32TySlot
getOrCreateTypeSlot(Type::Int64Ty ); // 8: Int64TySlot
}
SlotCalculator::SlotCalculator(const Module *M) {
assert(M);
TheModule = M;
insertPrimitives();
processModule();
}
// processModule - Process all of the module level function declarations and
// types that are available.
//
void SlotCalculator::processModule() {
SC_DEBUG("begin processModule!\n");
// Add all of the global variables to the value table...
//
for (Module::const_global_iterator I = TheModule->global_begin(),
E = TheModule->global_end(); I != E; ++I)
CreateSlotIfNeeded(I);
// Scavenge the types out of the functions, then add the functions themselves
// to the value table...
//
for (Module::const_iterator I = TheModule->begin(), E = TheModule->end();
I != E; ++I)
CreateSlotIfNeeded(I);
// Add all of the global aliases to the value table...
//
for (Module::const_alias_iterator I = TheModule->alias_begin(),
E = TheModule->alias_end(); I != E; ++I)
CreateSlotIfNeeded(I);
// Add all of the module level constants used as initializers
//
for (Module::const_global_iterator I = TheModule->global_begin(),
E = TheModule->global_end(); I != E; ++I)
if (I->hasInitializer())
CreateSlotIfNeeded(I->getInitializer());
// Add all of the module level constants used as aliasees
//
for (Module::const_alias_iterator I = TheModule->alias_begin(),
E = TheModule->alias_end(); I != E; ++I)
if (I->getAliasee())
CreateSlotIfNeeded(I->getAliasee());
// Now that all global constants have been added, rearrange constant planes
// that contain constant strings so that the strings occur at the start of the
// plane, not somewhere in the middle.
//
for (unsigned plane = 0, e = Table.size(); plane != e; ++plane) {
if (const ArrayType *AT = dyn_cast<ArrayType>(Types[plane]))
if (AT->getElementType() == Type::Int8Ty) {
TypePlane &Plane = Table[plane];
unsigned FirstNonStringID = 0;
for (unsigned i = 0, e = Plane.size(); i != e; ++i)
if (isa<ConstantAggregateZero>(Plane[i]) ||
(isa<ConstantArray>(Plane[i]) &&
cast<ConstantArray>(Plane[i])->isString())) {
// Check to see if we have to shuffle this string around. If not,
// don't do anything.
if (i != FirstNonStringID) {
// Swap the plane entries....
std::swap(Plane[i], Plane[FirstNonStringID]);
// Keep the NodeMap up to date.
NodeMap[Plane[i]] = i;
NodeMap[Plane[FirstNonStringID]] = FirstNonStringID;
}
++FirstNonStringID;
}
}
}
// Scan all of the functions for their constants, which allows us to emit
// more compact modules.
SC_DEBUG("Inserting function constants:\n");
for (Module::const_iterator F = TheModule->begin(), E = TheModule->end();
F != E; ++F) {
for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
OI != E; ++OI) {
if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
isa<InlineAsm>(*OI))
CreateSlotIfNeeded(*OI);
}
getOrCreateTypeSlot(I->getType());
}
}
// Insert constants that are named at module level into the slot pool so that
// the module symbol table can refer to them...
SC_DEBUG("Inserting SymbolTable values:\n");
processTypeSymbolTable(&TheModule->getTypeSymbolTable());
processValueSymbolTable(&TheModule->getValueSymbolTable());
// Now that we have collected together all of the information relevant to the
// module, compactify the type table if it is particularly big and outputting
// a bytecode file. The basic problem we run into is that some programs have
// a large number of types, which causes the type field to overflow its size,
// which causes instructions to explode in size (particularly call
// instructions). To avoid this behavior, we "sort" the type table so that
// all non-value types are pushed to the end of the type table, giving nice
// low numbers to the types that can be used by instructions, thus reducing
// the amount of explodage we suffer.
if (Types.size() >= 64) {
unsigned FirstNonValueTypeID = 0;
for (unsigned i = 0, e = Types.size(); i != e; ++i)
if (Types[i]->isFirstClassType() || Types[i]->isPrimitiveType()) {
// Check to see if we have to shuffle this type around. If not, don't
// do anything.
if (i != FirstNonValueTypeID) {
// Swap the type ID's.
std::swap(Types[i], Types[FirstNonValueTypeID]);
// Keep the TypeMap up to date.
TypeMap[Types[i]] = i;
TypeMap[Types[FirstNonValueTypeID]] = FirstNonValueTypeID;
// When we move a type, make sure to move its value plane as needed.
if (Table.size() > FirstNonValueTypeID) {
if (Table.size() <= i) Table.resize(i+1);
std::swap(Table[i], Table[FirstNonValueTypeID]);
}
}
++FirstNonValueTypeID;
}
}
NumModuleTypes = getNumPlanes();
SC_DEBUG("end processModule!\n");
}
// processTypeSymbolTable - Insert all of the type sin the specified symbol
// table.
void SlotCalculator::processTypeSymbolTable(const TypeSymbolTable *TST) {
for (TypeSymbolTable::const_iterator TI = TST->begin(), TE = TST->end();
TI != TE; ++TI )
getOrCreateTypeSlot(TI->second);
}
// processSymbolTable - Insert all of the values in the specified symbol table
// into the values table...
//
void SlotCalculator::processValueSymbolTable(const ValueSymbolTable *VST) {
for (ValueSymbolTable::const_iterator VI = VST->begin(), VE = VST->end();
VI != VE; ++VI)
CreateSlotIfNeeded(VI->getValue());
}
void SlotCalculator::CreateSlotIfNeeded(const Value *V) {
// Check to see if it's already in!
if (NodeMap.count(V)) return;
const Type *Ty = V->getType();
assert(Ty != Type::VoidTy && "Can't insert void values!");
if (const Constant *C = dyn_cast<Constant>(V)) {
if (isa<GlobalValue>(C)) {
// Initializers for globals are handled explicitly elsewhere.
} else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
// Do not index the characters that make up constant strings. We emit
// constant strings as special entities that don't require their
// individual characters to be emitted.
if (!C->isNullValue())
ConstantStrings.push_back(cast<ConstantArray>(C));
} else {
// This makes sure that if a constant has uses (for example an array of
// const ints), that they are inserted also.
for (User::const_op_iterator I = C->op_begin(), E = C->op_end();
I != E; ++I)
CreateSlotIfNeeded(*I);
}
}
unsigned TyPlane = getOrCreateTypeSlot(Ty);
if (Table.size() <= TyPlane) // Make sure we have the type plane allocated.
Table.resize(TyPlane+1, TypePlane());
// If this is the first value to get inserted into the type plane, make sure
// to insert the implicit null value.
if (Table[TyPlane].empty()) {
// Label's and opaque types can't have a null value.
if (Ty != Type::LabelTy && !isa<OpaqueType>(Ty)) {
Value *ZeroInitializer = Constant::getNullValue(Ty);
// If we are pushing zeroinit, it will be handled below.
if (V != ZeroInitializer) {
Table[TyPlane].push_back(ZeroInitializer);
NodeMap[ZeroInitializer] = 0;
}
}
}
// Insert node into table and NodeMap...
NodeMap[V] = Table[TyPlane].size();
Table[TyPlane].push_back(V);
SC_DEBUG(" Inserting value [" << TyPlane << "] = " << *V << " slot=" <<
NodeMap[V] << "\n");
}
unsigned SlotCalculator::getOrCreateTypeSlot(const Type *Ty) {
TypeMapType::iterator TyIt = TypeMap.find(Ty);
if (TyIt != TypeMap.end()) return TyIt->second;
// Insert into TypeMap.
unsigned ResultSlot = TypeMap[Ty] = Types.size();
Types.push_back(Ty);
SC_DEBUG(" Inserting type [" << ResultSlot << "] = " << *Ty << "\n" );
// Loop over any contained types in the definition, ensuring they are also
// inserted.
for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
I != E; ++I)
getOrCreateTypeSlot(*I);
return ResultSlot;
}
void SlotCalculator::incorporateFunction(const Function *F) {
SC_DEBUG("begin processFunction!\n");
// Iterate over function arguments, adding them to the value table...
for(Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I)
CreateFunctionValueSlot(I);
SC_DEBUG("Inserting Instructions:\n");
// Add all of the instructions to the type planes...
for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
CreateFunctionValueSlot(BB);
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
if (I->getType() != Type::VoidTy)
CreateFunctionValueSlot(I);
}
}
SC_DEBUG("end processFunction!\n");
}
void SlotCalculator::purgeFunction() {
SC_DEBUG("begin purgeFunction!\n");
// Next, remove values from existing type planes
for (DenseMap<unsigned,unsigned,
ModuleLevelDenseMapKeyInfo>::iterator I = ModuleLevel.begin(),
E = ModuleLevel.end(); I != E; ++I) {
unsigned PlaneNo = I->first;
unsigned ModuleLev = I->second;
// Pop all function-local values in this type-plane off of Table.
TypePlane &Plane = getPlane(PlaneNo);
assert(ModuleLev < Plane.size() && "module levels higher than elements?");
for (unsigned i = ModuleLev, e = Plane.size(); i != e; ++i) {
NodeMap.erase(Plane.back()); // Erase from nodemap
Plane.pop_back(); // Shrink plane
}
}
ModuleLevel.clear();
// Finally, remove any type planes defined by the function...
while (Table.size() > NumModuleTypes) {
TypePlane &Plane = Table.back();
SC_DEBUG("Removing Plane " << (Table.size()-1) << " of size "
<< Plane.size() << "\n");
for (unsigned i = 0, e = Plane.size(); i != e; ++i)
NodeMap.erase(Plane[i]); // Erase from nodemap
Table.pop_back(); // Nuke the plane, we don't like it.
}
SC_DEBUG("end purgeFunction!\n");
}
inline static bool hasImplicitNull(const Type* Ty) {
return Ty != Type::LabelTy && Ty != Type::VoidTy && !isa<OpaqueType>(Ty);
}
void SlotCalculator::CreateFunctionValueSlot(const Value *V) {
assert(!NodeMap.count(V) && "Function-local value can't be inserted!");
const Type *Ty = V->getType();
assert(Ty != Type::VoidTy && "Can't insert void values!");
assert(!isa<Constant>(V) && "Not a function-local value!");
unsigned TyPlane = getOrCreateTypeSlot(Ty);
if (Table.size() <= TyPlane) // Make sure we have the type plane allocated.
Table.resize(TyPlane+1, TypePlane());
// If this is the first value noticed of this type within this function,
// remember the module level for this type plane in ModuleLevel. This reminds
// us to remove the values in purgeFunction and tells us how many to remove.
if (TyPlane < NumModuleTypes)
ModuleLevel.insert(std::make_pair(TyPlane, Table[TyPlane].size()));
// If this is the first value to get inserted into the type plane, make sure
// to insert the implicit null value.
if (Table[TyPlane].empty()) {
// Label's and opaque types can't have a null value.
if (hasImplicitNull(Ty)) {
Value *ZeroInitializer = Constant::getNullValue(Ty);
// If we are pushing zeroinit, it will be handled below.
if (V != ZeroInitializer) {
Table[TyPlane].push_back(ZeroInitializer);
NodeMap[ZeroInitializer] = 0;
}
}
}
// Insert node into table and NodeMap...
NodeMap[V] = Table[TyPlane].size();
Table[TyPlane].push_back(V);
SC_DEBUG(" Inserting value [" << TyPlane << "] = " << *V << " slot=" <<
NodeMap[V] << "\n");
}