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llvm/lib/Bytecode/Writer/SlotCalculator.cpp
Chris Lattner a55866f2cc Eliminate a log(n) lookup 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33155 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-12 23:23:08 +00:00

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//===-- 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/SymbolTable.h"
#include "llvm/TypeSymbolTable.h"
#include "llvm/Type.h"
#include "llvm/Analysis/ConstantsScanner.h"
#include "llvm/ADT/PostOrderIterator.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
insertType(Type::VoidTy, true); // 0: VoidTySlot
insertType(Type::FloatTy, true); // 1: FloatTySlot
insertType(Type::DoubleTy, true); // 2: DoubleTySlot
insertType(Type::LabelTy, true); // 3: LabelTySlot
assert(TypeMap.size() == Type::FirstDerivedTyID && "Invalid primitive insert");
// Above here *must* correspond 1:1 with the primitive types.
insertType(Type::Int1Ty, true); // 4: BoolTySlot
insertType(Type::Int8Ty, true); // 5: Int8TySlot
insertType(Type::Int16Ty, true); // 6: Int16TySlot
insertType(Type::Int32Ty, true); // 7: Int32TySlot
insertType(Type::Int64Ty, true); // 8: Int64TySlot
}
SlotCalculator::SlotCalculator(const Module *M ) {
ModuleContainsAllFunctionConstants = false;
ModuleTypeLevel = 0;
TheModule = M;
insertPrimitives();
if (M == 0) return; // Empty table...
processModule();
}
SlotCalculator::SlotCalculator(const Function *M ) {
ModuleContainsAllFunctionConstants = false;
TheModule = M ? M->getParent() : 0;
insertPrimitives();
if (TheModule == 0) return; // Empty table...
processModule(); // Process module level stuff
incorporateFunction(M); // Start out in incorporated state
}
unsigned SlotCalculator::getGlobalSlot(const Value *V) const {
assert(!CompactionTable.empty() &&
"This method can only be used when compaction is enabled!");
std::map<const Value*, unsigned>::const_iterator I = NodeMap.find(V);
assert(I != NodeMap.end() && "Didn't find global slot entry!");
return I->second;
}
unsigned SlotCalculator::getGlobalSlot(const Type* T) const {
std::map<const Type*, unsigned>::const_iterator I = TypeMap.find(T);
assert(I != TypeMap.end() && "Didn't find global slot entry!");
return I->second;
}
SlotCalculator::TypePlane &SlotCalculator::getPlane(unsigned Plane) {
if (CompactionTable.empty()) { // No compaction table active?
// fall out
} else if (!CompactionTable[Plane].empty()) { // Compaction table active.
assert(Plane < CompactionTable.size());
return CompactionTable[Plane];
} else {
// Final case: compaction table active, but this plane is not
// compactified. If the type plane is compactified, unmap back to the
// global type plane corresponding to "Plane".
if (!CompactionTypes.empty()) {
const Type *Ty = CompactionTypes[Plane];
TypeMapType::iterator It = TypeMap.find(Ty);
assert(It != TypeMap.end() && "Type not in global constant map?");
Plane = It->second;
}
}
// Okay we are just returning an entry out of the main Table. Make sure the
// plane exists and return it.
if (Plane >= Table.size())
Table.resize(Plane+1);
return Table[Plane];
}
// 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)
getOrCreateSlot(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)
getOrCreateSlot(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())
getOrCreateSlot(I->getInitializer());
// 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. This is optional, and is just used to compactify
// the constants used by different functions together.
//
// This functionality tends to produce smaller bytecode files. This should
// not be used in the future by clients that want to, for example, build and
// emit functions on the fly. For now, however, it is unconditionally
// enabled.
ModuleContainsAllFunctionConstants = true;
SC_DEBUG("Inserting function constants:\n");
for (Module::const_iterator F = TheModule->begin(), E = TheModule->end();
F != E; ++F) {
for (const_inst_iterator I = inst_begin(F), E = inst_end(F); 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))
getOrCreateSlot(*OI);
}
getOrCreateSlot(I->getType());
}
processSymbolTableConstants(&F->getValueSymbolTable());
}
// 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;
}
}
SC_DEBUG("end processModule!\n");
}
// processTypeSymbolTable - Insert all of the type sin the specified symbol
// table.
void SlotCalculator::processTypeSymbolTable(const TypeSymbolTable *ST) {
for (TypeSymbolTable::const_iterator TI = ST->begin(), TE = ST->end();
TI != TE; ++TI )
getOrCreateSlot(TI->second);
}
// processSymbolTable - Insert all of the values in the specified symbol table
// into the values table...
//
void SlotCalculator::processValueSymbolTable(const SymbolTable *ST) {
for (SymbolTable::plane_const_iterator PI = ST->plane_begin(),
PE = ST->plane_end(); PI != PE; ++PI)
for (SymbolTable::value_const_iterator VI = PI->second.begin(),
VE = PI->second.end(); VI != VE; ++VI)
getOrCreateSlot(VI->second);
}
void SlotCalculator::processSymbolTableConstants(const SymbolTable *ST) {
// Now do the constant values in all planes
for (SymbolTable::plane_const_iterator PI = ST->plane_begin(),
PE = ST->plane_end(); PI != PE; ++PI)
for (SymbolTable::value_const_iterator VI = PI->second.begin(),
VE = PI->second.end(); VI != VE; ++VI)
if (isa<Constant>(VI->second) &&
!isa<GlobalValue>(VI->second))
getOrCreateSlot(VI->second);
}
void SlotCalculator::incorporateFunction(const Function *F) {
assert((ModuleLevel.empty() ||
ModuleTypeLevel == 0) && "Module already incorporated!");
SC_DEBUG("begin processFunction!\n");
// If we emitted all of the function constants, build a compaction table.
if (ModuleContainsAllFunctionConstants)
buildCompactionTable(F);
// Update the ModuleLevel entries to be accurate.
ModuleLevel.resize(getNumPlanes());
for (unsigned i = 0, e = getNumPlanes(); i != e; ++i)
ModuleLevel[i] = getPlane(i).size();
ModuleTypeLevel = Types.size();
// 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)
getOrCreateSlot(I);
if (!ModuleContainsAllFunctionConstants) {
// Iterate over all of the instructions in the function, looking for
// constant values that are referenced. Add these to the value pools
// before any nonconstant values. This will be turned into the constant
// pool for the bytecode writer.
//
// Emit all of the constants that are being used by the instructions in
// the function...
for (constant_iterator CI = constant_begin(F), CE = constant_end(F);
CI != CE; ++CI)
getOrCreateSlot(*CI);
// If there is a symbol table, it is possible that the user has names for
// constants that are not being used. In this case, we will have problems
// if we don't emit the constants now, because otherwise we will get
// symbol table references to constants not in the output. Scan for these
// constants now.
//
processSymbolTableConstants(&F->getValueSymbolTable());
}
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) {
getOrCreateSlot(BB);
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
getOrCreateSlot(I);
}
}
// If we are building a compaction table, prune out planes that do not benefit
// from being compactified.
if (!CompactionTable.empty())
pruneCompactionTable();
SC_DEBUG("end processFunction!\n");
}
void SlotCalculator::purgeFunction() {
assert((ModuleLevel.size() != 0 ||
ModuleTypeLevel != 0) && "Module not incorporated!");
unsigned NumModuleTypes = ModuleLevel.size();
SC_DEBUG("begin purgeFunction!\n");
// First, free the compaction map if used.
CompactionNodeMap.clear();
CompactionTypeMap.clear();
// Next, remove values from existing type planes
for (unsigned i = 0; i != NumModuleTypes; ++i) {
// Size of plane before function came
unsigned ModuleLev = getModuleLevel(i);
assert(int(ModuleLev) >= 0 && "BAD!");
TypePlane &Plane = getPlane(i);
assert(ModuleLev <= Plane.size() && "module levels higher than elements?");
while (Plane.size() != ModuleLev) {
assert(!isa<GlobalValue>(Plane.back()) &&
"Functions cannot define globals!");
NodeMap.erase(Plane.back()); // Erase from nodemap
Plane.pop_back(); // Shrink plane
}
}
// We don't need this state anymore, free it up.
ModuleLevel.clear();
ModuleTypeLevel = 0;
// Finally, remove any type planes defined by the function...
CompactionTypes.clear();
if (!CompactionTable.empty()) {
CompactionTable.clear();
} else {
while (Table.size() > NumModuleTypes) {
TypePlane &Plane = Table.back();
SC_DEBUG("Removing Plane " << (Table.size()-1) << " of size "
<< Plane.size() << "\n");
while (Plane.size()) {
assert(!isa<GlobalValue>(Plane.back()) &&
"Functions cannot define globals!");
NodeMap.erase(Plane.back()); // Erase from nodemap
Plane.pop_back(); // Shrink plane
}
Table.pop_back(); // Nuke the plane, we don't like it.
}
}
SC_DEBUG("end purgeFunction!\n");
}
static inline bool hasNullValue(const Type *Ty) {
return Ty != Type::LabelTy && Ty != Type::VoidTy && !isa<OpaqueType>(Ty);
}
/// getOrCreateCompactionTableSlot - This method is used to build up the initial
/// approximation of the compaction table.
unsigned SlotCalculator::getOrCreateCompactionTableSlot(const Value *V) {
std::map<const Value*, unsigned>::iterator I =
CompactionNodeMap.lower_bound(V);
if (I != CompactionNodeMap.end() && I->first == V)
return I->second; // Already exists?
// Make sure the type is in the table.
unsigned Ty;
if (!CompactionTypes.empty())
Ty = getOrCreateCompactionTableSlot(V->getType());
else // If the type plane was decompactified, use the global plane ID
Ty = getSlot(V->getType());
if (CompactionTable.size() <= Ty)
CompactionTable.resize(Ty+1);
TypePlane &TyPlane = CompactionTable[Ty];
// Make sure to insert the null entry if the thing we are inserting is not a
// null constant.
if (TyPlane.empty() && hasNullValue(V->getType())) {
Value *ZeroInitializer = Constant::getNullValue(V->getType());
if (V != ZeroInitializer) {
TyPlane.push_back(ZeroInitializer);
CompactionNodeMap[ZeroInitializer] = 0;
}
}
unsigned SlotNo = TyPlane.size();
TyPlane.push_back(V);
CompactionNodeMap.insert(std::make_pair(V, SlotNo));
return SlotNo;
}
/// getOrCreateCompactionTableSlot - This method is used to build up the initial
/// approximation of the compaction table.
unsigned SlotCalculator::getOrCreateCompactionTableSlot(const Type *T) {
CompactionTypeMapType::iterator I = CompactionTypeMap.lower_bound(T);
if (I != CompactionTypeMap.end() && I->first == T)
return I->second; // Already exists?
unsigned SlotNo = CompactionTypes.size();
SC_DEBUG("Inserting Compaction Type #" << SlotNo << ": " << *T << "\n");
CompactionTypes.push_back(T);
CompactionTypeMap.insert(I, std::make_pair(T, SlotNo));
return SlotNo;
}
/// buildCompactionTable - Since all of the function constants and types are
/// stored in the module-level constant table, we don't need to emit a function
/// constant table. Also due to this, the indices for various constants and
/// types might be very large in large programs. In order to avoid blowing up
/// the size of instructions in the bytecode encoding, we build a compaction
/// table, which defines a mapping from function-local identifiers to global
/// identifiers.
void SlotCalculator::buildCompactionTable(const Function *F) {
assert(CompactionNodeMap.empty() && "Compaction table already built!");
assert(CompactionTypeMap.empty() && "Compaction types already built!");
// First step, insert the primitive types.
CompactionTable.resize(Type::LastPrimitiveTyID+1);
for (unsigned i = 0; i <= Type::LastPrimitiveTyID; ++i) {
const Type *PrimTy = Type::getPrimitiveType((Type::TypeID)i);
CompactionTypes.push_back(PrimTy);
CompactionTypeMap[PrimTy] = i;
}
CompactionTypeMap[Type::Int1Ty] = CompactionTypes.size();
CompactionTypes.push_back(Type::Int1Ty);
CompactionTypeMap[Type::Int8Ty] = CompactionTypes.size();
CompactionTypes.push_back(Type::Int8Ty);
CompactionTypeMap[Type::Int16Ty] = CompactionTypes.size();
CompactionTypes.push_back(Type::Int16Ty);
CompactionTypeMap[Type::Int32Ty] = CompactionTypes.size();
CompactionTypes.push_back(Type::Int32Ty);
CompactionTypeMap[Type::Int64Ty] = CompactionTypes.size();
CompactionTypes.push_back(Type::Int64Ty);
// Next, include any types used by function arguments.
for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I)
getOrCreateCompactionTableSlot(I->getType());
// Next, find all of the types and values that are referred to by the
// instructions in the function.
for (const_inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
getOrCreateCompactionTableSlot(I->getType());
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
if (isa<Constant>(I->getOperand(op)) || isa<InlineAsm>(I->getOperand(op)))
getOrCreateCompactionTableSlot(I->getOperand(op));
}
// Now do the constants and global values
const SymbolTable &ST = F->getValueSymbolTable();
for (SymbolTable::plane_const_iterator PI = ST.plane_begin(),
PE = ST.plane_end(); PI != PE; ++PI)
for (SymbolTable::value_const_iterator VI = PI->second.begin(),
VE = PI->second.end(); VI != VE; ++VI)
if (isa<Constant>(VI->second) && !isa<GlobalValue>(VI->second))
getOrCreateCompactionTableSlot(VI->second);
// Now that we have all of the values in the table, and know what types are
// referenced, make sure that there is at least the zero initializer in any
// used type plane. Since the type was used, we will be emitting instructions
// to the plane even if there are no constants in it.
CompactionTable.resize(CompactionTypes.size());
for (unsigned i = 0, e = CompactionTable.size(); i != e; ++i)
if (CompactionTable[i].empty() && (i != Type::VoidTyID) &&
i != Type::LabelTyID) {
const Type *Ty = CompactionTypes[i];
SC_DEBUG("Getting Null Value #" << i << " for Type " << *Ty << "\n");
assert(Ty->getTypeID() != Type::VoidTyID);
assert(Ty->getTypeID() != Type::LabelTyID);
getOrCreateCompactionTableSlot(Constant::getNullValue(Ty));
}
// Okay, now at this point, we have a legal compaction table. Since we want
// to emit the smallest possible binaries, do not compactify the type plane if
// it will not save us anything. Because we have not yet incorporated the
// function body itself yet, we don't know whether or not it's a good idea to
// compactify other planes. We will defer this decision until later.
TypeList &GlobalTypes = Types;
// All of the values types will be scrunched to the start of the types plane
// of the global table. Figure out just how many there are.
assert(!GlobalTypes.empty() && "No global types???");
unsigned NumFCTypes = GlobalTypes.size()-1;
while (!GlobalTypes[NumFCTypes]->isFirstClassType())
--NumFCTypes;
// If there are fewer that 64 types, no instructions will be exploded due to
// the size of the type operands. Thus there is no need to compactify types.
// Also, if the compaction table contains most of the entries in the global
// table, there really is no reason to compactify either.
if (NumFCTypes < 64) {
// Decompactifying types is tricky, because we have to move type planes all
// over the place. At least we don't need to worry about updating the
// CompactionNodeMap for non-types though.
std::vector<TypePlane> TmpCompactionTable;
std::swap(CompactionTable, TmpCompactionTable);
TypeList TmpTypes;
std::swap(TmpTypes, CompactionTypes);
// Move each plane back over to the uncompactified plane
while (!TmpTypes.empty()) {
const Type *Ty = TmpTypes.back();
TmpTypes.pop_back();
CompactionTypeMap.erase(Ty); // Decompactify type!
// Find the global slot number for this type.
int TySlot = getSlot(Ty);
assert(TySlot != -1 && "Type doesn't exist in global table?");
// Now we know where to put the compaction table plane.
if (CompactionTable.size() <= unsigned(TySlot))
CompactionTable.resize(TySlot+1);
// Move the plane back into the compaction table.
std::swap(CompactionTable[TySlot], TmpCompactionTable[TmpTypes.size()]);
// And remove the empty plane we just moved in.
TmpCompactionTable.pop_back();
}
}
}
/// pruneCompactionTable - Once the entire function being processed has been
/// incorporated into the current compaction table, look over the compaction
/// table and check to see if there are any values whose compaction will not
/// save us any space in the bytecode file. If compactifying these values
/// serves no purpose, then we might as well not even emit the compactification
/// information to the bytecode file, saving a bit more space.
///
/// Note that the type plane has already been compactified if possible.
///
void SlotCalculator::pruneCompactionTable() {
TypeList &TyPlane = CompactionTypes;
for (unsigned ctp = 0, e = CompactionTable.size(); ctp != e; ++ctp)
if (!CompactionTable[ctp].empty()) {
TypePlane &CPlane = CompactionTable[ctp];
unsigned GlobalSlot = ctp;
if (!TyPlane.empty())
GlobalSlot = getGlobalSlot(TyPlane[ctp]);
if (GlobalSlot >= Table.size())
Table.resize(GlobalSlot+1);
TypePlane &GPlane = Table[GlobalSlot];
unsigned ModLevel = getModuleLevel(ctp);
unsigned NumFunctionObjs = CPlane.size()-ModLevel;
// If the maximum index required if all entries in this plane were merged
// into the global plane is less than 64, go ahead and eliminate the
// plane.
bool PrunePlane = GPlane.size() + NumFunctionObjs < 64;
// If there are no function-local values defined, and the maximum
// referenced global entry is less than 64, we don't need to compactify.
if (!PrunePlane && NumFunctionObjs == 0) {
unsigned MaxIdx = 0;
for (unsigned i = 0; i != ModLevel; ++i) {
unsigned Idx = NodeMap[CPlane[i]];
if (Idx > MaxIdx) MaxIdx = Idx;
}
PrunePlane = MaxIdx < 64;
}
// Ok, finally, if we decided to prune this plane out of the compaction
// table, do so now.
if (PrunePlane) {
TypePlane OldPlane;
std::swap(OldPlane, CPlane);
// Loop over the function local objects, relocating them to the global
// table plane.
for (unsigned i = ModLevel, e = OldPlane.size(); i != e; ++i) {
const Value *V = OldPlane[i];
CompactionNodeMap.erase(V);
assert(NodeMap.count(V) == 0 && "Value already in table??");
getOrCreateSlot(V);
}
// For compactified global values, just remove them from the compaction
// node map.
for (unsigned i = 0; i != ModLevel; ++i)
CompactionNodeMap.erase(OldPlane[i]);
// Update the new modulelevel for this plane.
assert(ctp < ModuleLevel.size() && "Cannot set modulelevel!");
ModuleLevel[ctp] = GPlane.size()-NumFunctionObjs;
assert((int)ModuleLevel[ctp] >= 0 && "Bad computation!");
}
}
}
/// Determine if the compaction table is actually empty. Because the
/// compaction table always includes the primitive type planes, we
/// can't just check getCompactionTable().size() because it will never
/// be zero. Furthermore, the ModuleLevel factors into whether a given
/// plane is empty or not. This function does the necessary computation
/// to determine if its actually empty.
bool SlotCalculator::CompactionTableIsEmpty() const {
// Check a degenerate case, just in case.
if (CompactionTable.empty())
return true;
// Check each plane
for (unsigned i = 0, e = CompactionTable.size(); i < e; ++i) {
// If the plane is not empty
if (!CompactionTable[i].empty()) {
// If the module level is non-zero then at least the
// first element of the plane is valid and therefore not empty.
unsigned End = getModuleLevel(i);
if (End != 0)
return false;
}
}
// All the compaction table planes are empty so the table is
// considered empty too.
return true;
}
int SlotCalculator::getSlot(const Value *V) const {
// If there is a CompactionTable active...
if (!CompactionNodeMap.empty()) {
std::map<const Value*, unsigned>::const_iterator I =
CompactionNodeMap.find(V);
if (I != CompactionNodeMap.end())
return (int)I->second;
// Otherwise, if it's not in the compaction table, it must be in a
// non-compactified plane.
}
std::map<const Value*, unsigned>::const_iterator I = NodeMap.find(V);
if (I != NodeMap.end())
return (int)I->second;
return -1;
}
int SlotCalculator::getSlot(const Type*T) const {
// If there is a CompactionTable active...
if (!CompactionTypeMap.empty()) {
std::map<const Type*, unsigned>::const_iterator I =
CompactionTypeMap.find(T);
if (I != CompactionTypeMap.end())
return (int)I->second;
// Otherwise, if it's not in the compaction table, it must be in a
// non-compactified plane.
}
std::map<const Type*, unsigned>::const_iterator I = TypeMap.find(T);
if (I != TypeMap.end())
return (int)I->second;
return -1;
}
int SlotCalculator::getOrCreateSlot(const Value *V) {
if (V->getType() == Type::VoidTy) return -1;
int SlotNo = getSlot(V); // Check to see if it's already in!
if (SlotNo != -1) return SlotNo;
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
assert(GV->getParent() != 0 && "Global not embedded into a module!");
if (!isa<GlobalValue>(V)) // Initializers for globals are handled explicitly
if (const Constant *C = dyn_cast<Constant>(V)) {
assert(CompactionNodeMap.empty() &&
"All needed constants should be in the compaction map already!");
// 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 (!isa<ConstantArray>(C) || !cast<ConstantArray>(C)->isString()) {
// 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)
getOrCreateSlot(*I);
} else {
assert(ModuleLevel.empty() &&
"How can a constant string be directly accessed in a function?");
// Otherwise, if we are emitting a bytecode file and this IS a string,
// remember it.
if (!C->isNullValue())
ConstantStrings.push_back(cast<ConstantArray>(C));
}
}
return insertValue(V);
}
int SlotCalculator::getOrCreateSlot(const Type* T) {
int SlotNo = getSlot(T); // Check to see if it's already in!
if (SlotNo != -1) return SlotNo;
return insertType(T);
}
int SlotCalculator::insertValue(const Value *D, bool dontIgnore) {
assert(D && "Can't insert a null value!");
assert(getSlot(D) == -1 && "Value is already in the table!");
// If we are building a compaction map, and if this plane is being compacted,
// insert the value into the compaction map, not into the global map.
if (!CompactionNodeMap.empty()) {
if (D->getType() == Type::VoidTy) return -1; // Do not insert void values
assert(!isa<Constant>(D) &&
"Types, constants, and globals should be in global table!");
int Plane = getSlot(D->getType());
assert(Plane != -1 && CompactionTable.size() > (unsigned)Plane &&
"Didn't find value type!");
if (!CompactionTable[Plane].empty())
return getOrCreateCompactionTableSlot(D);
}
// If this node does not contribute to a plane, or if the node has a
// name and we don't want names, then ignore the silly node... Note that types
// do need slot numbers so that we can keep track of where other values land.
//
if (!dontIgnore) // Don't ignore nonignorables!
if (D->getType() == Type::VoidTy ) { // Ignore void type nodes
SC_DEBUG("ignored value " << *D << "\n");
return -1; // We do need types unconditionally though
}
// Okay, everything is happy, actually insert the silly value now...
return doInsertValue(D);
}
int SlotCalculator::insertType(const Type *Ty, bool dontIgnore) {
assert(Ty && "Can't insert a null type!");
assert(getSlot(Ty) == -1 && "Type is already in the table!");
// If we are building a compaction map, and if this plane is being compacted,
// insert the value into the compaction map, not into the global map.
if (!CompactionTypeMap.empty()) {
getOrCreateCompactionTableSlot(Ty);
}
// Insert the current type before any subtypes. This is important because
// recursive types elements are inserted in a bottom up order. Changing
// this here can break things. For example:
//
// global { \2 * } { { \2 }* null }
//
int ResultSlot = doInsertType(Ty);
SC_DEBUG(" Inserted type: " << Ty->getDescription() << " slot=" <<
ResultSlot << "\n");
// Loop over any contained types in the definition... in post
// order.
for (po_iterator<const Type*> I = po_begin(Ty), E = po_end(Ty);
I != E; ++I) {
if (*I != Ty) {
const Type *SubTy = *I;
// If we haven't seen this sub type before, add it to our type table!
if (getSlot(SubTy) == -1) {
SC_DEBUG(" Inserting subtype: " << SubTy->getDescription() << "\n");
doInsertType(SubTy);
SC_DEBUG(" Inserted subtype: " << SubTy->getDescription() << "\n");
}
}
}
return ResultSlot;
}
// doInsertValue - This is a small helper function to be called only
// be insertValue.
//
int SlotCalculator::doInsertValue(const Value *D) {
const Type *Typ = D->getType();
unsigned Ty;
// Used for debugging DefSlot=-1 assertion...
//if (Typ == Type::TypeTy)
// llvm_cerr << "Inserting type '"<<cast<Type>(D)->getDescription() <<"'!\n";
if (Typ->isDerivedType()) {
int ValSlot;
if (CompactionTable.empty())
ValSlot = getSlot(Typ);
else
ValSlot = getGlobalSlot(Typ);
if (ValSlot == -1) { // Have we already entered this type?
// Nope, this is the first we have seen the type, process it.
ValSlot = insertType(Typ, true);
assert(ValSlot != -1 && "ProcessType returned -1 for a type?");
}
Ty = (unsigned)ValSlot;
} else {
Ty = Typ->getTypeID();
}
if (Table.size() <= Ty) // Make sure we have the type plane allocated...
Table.resize(Ty+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[Ty].empty() && hasNullValue(Typ)) {
Value *ZeroInitializer = Constant::getNullValue(Typ);
// If we are pushing zeroinit, it will be handled below.
if (D != ZeroInitializer) {
Table[Ty].push_back(ZeroInitializer);
NodeMap[ZeroInitializer] = 0;
}
}
// Insert node into table and NodeMap...
unsigned DestSlot = NodeMap[D] = Table[Ty].size();
Table[Ty].push_back(D);
SC_DEBUG(" Inserting value [" << Ty << "] = " << *D << " slot=" <<
DestSlot << " [");
// G = Global, C = Constant, T = Type, F = Function, o = other
SC_DEBUG((isa<GlobalVariable>(D) ? "G" : (isa<Constant>(D) ? "C" :
(isa<Function>(D) ? "F" : "o"))));
SC_DEBUG("]\n");
return (int)DestSlot;
}
// doInsertType - This is a small helper function to be called only
// be insertType.
//
int SlotCalculator::doInsertType(const Type *Ty) {
// Insert node into table and NodeMap...
unsigned DestSlot = TypeMap[Ty] = Types.size();
Types.push_back(Ty);
SC_DEBUG(" Inserting type [" << DestSlot << "] = " << *Ty << "\n" );
return (int)DestSlot;
}
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