1 //===-- ValueEnumerator.cpp - Number values and types for bitcode writer --===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Chris Lattner and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the ValueEnumerator class.
12 //===----------------------------------------------------------------------===//
14 #include "ValueEnumerator.h"
15 #include "llvm/Constants.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/Module.h"
18 #include "llvm/TypeSymbolTable.h"
19 #include "llvm/ValueSymbolTable.h"
20 #include "llvm/Instructions.h"
24 static bool isFirstClassType(const std::pair<const llvm::Type*,
26 return P.first->isFirstClassType();
29 static bool isIntegerValue(const std::pair<const Value*, unsigned> &V) {
30 return isa<IntegerType>(V.first->getType());
33 static bool CompareByFrequency(const std::pair<const llvm::Type*,
35 const std::pair<const llvm::Type*,
37 return P1.second > P2.second;
40 /// ValueEnumerator - Enumerate module-level information.
41 ValueEnumerator::ValueEnumerator(const Module *M) {
42 // Enumerate the global variables.
43 for (Module::const_global_iterator I = M->global_begin(),
44 E = M->global_end(); I != E; ++I)
47 // Enumerate the functions.
48 for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
50 EnumerateParamAttrs(cast<Function>(I)->getParamAttrs());
53 // Enumerate the aliases.
54 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
58 // Remember what is the cutoff between globalvalue's and other constants.
59 unsigned FirstConstant = Values.size();
61 // Enumerate the global variable initializers.
62 for (Module::const_global_iterator I = M->global_begin(),
63 E = M->global_end(); I != E; ++I)
64 if (I->hasInitializer())
65 EnumerateValue(I->getInitializer());
67 // Enumerate the aliasees.
68 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
70 EnumerateValue(I->getAliasee());
72 // Enumerate types used by the type symbol table.
73 EnumerateTypeSymbolTable(M->getTypeSymbolTable());
75 // Insert constants that are named at module level into the slot pool so that
76 // the module symbol table can refer to them...
77 EnumerateValueSymbolTable(M->getValueSymbolTable());
79 // Enumerate types used by function bodies and argument lists.
80 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
82 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
84 EnumerateType(I->getType());
86 for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
87 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
88 for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
90 EnumerateOperandType(*OI);
91 EnumerateType(I->getType());
92 if (const CallInst *CI = dyn_cast<CallInst>(I))
93 EnumerateParamAttrs(CI->getParamAttrs());
94 else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
95 EnumerateParamAttrs(II->getParamAttrs());
99 // Optimize constant ordering.
100 OptimizeConstants(FirstConstant, Values.size());
102 // Sort the type table by frequency so that most commonly used types are early
103 // in the table (have low bit-width).
104 std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);
106 // Partition the Type ID's so that the first-class types occur before the
107 // aggregate types. This allows the aggregate types to be dropped from the
108 // type table after parsing the global variable initializers.
109 std::partition(Types.begin(), Types.end(), isFirstClassType);
111 // Now that we rearranged the type table, rebuild TypeMap.
112 for (unsigned i = 0, e = Types.size(); i != e; ++i)
113 TypeMap[Types[i].first] = i+1;
116 // Optimize constant ordering.
117 struct CstSortPredicate {
119 CstSortPredicate(ValueEnumerator &ve) : VE(ve) {}
120 bool operator()(const std::pair<const Value*, unsigned> &LHS,
121 const std::pair<const Value*, unsigned> &RHS) {
123 if (LHS.first->getType() != RHS.first->getType())
124 return VE.getTypeID(LHS.first->getType()) <
125 VE.getTypeID(RHS.first->getType());
126 // Then by frequency.
127 return LHS.second > RHS.second;
131 /// OptimizeConstants - Reorder constant pool for denser encoding.
132 void ValueEnumerator::OptimizeConstants(unsigned CstStart, unsigned CstEnd) {
133 if (CstStart == CstEnd || CstStart+1 == CstEnd) return;
135 CstSortPredicate P(*this);
136 std::stable_sort(Values.begin()+CstStart, Values.begin()+CstEnd, P);
138 // Ensure that integer constants are at the start of the constant pool. This
139 // is important so that GEP structure indices come before gep constant exprs.
140 std::partition(Values.begin()+CstStart, Values.begin()+CstEnd,
143 // Rebuild the modified portion of ValueMap.
144 for (; CstStart != CstEnd; ++CstStart)
145 ValueMap[Values[CstStart].first] = CstStart+1;
149 /// EnumerateTypeSymbolTable - Insert all of the types in the specified symbol
151 void ValueEnumerator::EnumerateTypeSymbolTable(const TypeSymbolTable &TST) {
152 for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
154 EnumerateType(TI->second);
157 /// EnumerateValueSymbolTable - Insert all of the values in the specified symbol
158 /// table into the values table.
159 void ValueEnumerator::EnumerateValueSymbolTable(const ValueSymbolTable &VST) {
160 for (ValueSymbolTable::const_iterator VI = VST.begin(), VE = VST.end();
162 EnumerateValue(VI->getValue());
165 void ValueEnumerator::EnumerateValue(const Value *V) {
166 assert(V->getType() != Type::VoidTy && "Can't insert void values!");
168 // Check to see if it's already in!
169 unsigned &ValueID = ValueMap[V];
171 // Increment use count.
172 Values[ValueID-1].second++;
176 // Enumerate the type of this value.
177 EnumerateType(V->getType());
179 if (const Constant *C = dyn_cast<Constant>(V)) {
180 if (isa<GlobalValue>(C)) {
181 // Initializers for globals are handled explicitly elsewhere.
182 } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
183 // Do not enumerate the initializers for an array of simple characters.
184 // The initializers just polute the value table, and we emit the strings
186 } else if (C->getNumOperands()) {
187 // If a constant has operands, enumerate them. This makes sure that if a
188 // constant has uses (for example an array of const ints), that they are
191 // We prefer to enumerate them with values before we enumerate the user
192 // itself. This makes it more likely that we can avoid forward references
193 // in the reader. We know that there can be no cycles in the constants
194 // graph that don't go through a global variable.
195 for (User::const_op_iterator I = C->op_begin(), E = C->op_end();
199 // Finally, add the value. Doing this could make the ValueID reference be
200 // dangling, don't reuse it.
201 Values.push_back(std::make_pair(V, 1U));
202 ValueMap[V] = Values.size();
208 Values.push_back(std::make_pair(V, 1U));
209 ValueID = Values.size();
213 void ValueEnumerator::EnumerateType(const Type *Ty) {
214 unsigned &TypeID = TypeMap[Ty];
217 // If we've already seen this type, just increase its occurrence count.
218 Types[TypeID-1].second++;
222 // First time we saw this type, add it.
223 Types.push_back(std::make_pair(Ty, 1U));
224 TypeID = Types.size();
226 // Enumerate subtypes.
227 for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
232 // Enumerate the types for the specified value. If the value is a constant,
233 // walk through it, enumerating the types of the constant.
234 void ValueEnumerator::EnumerateOperandType(const Value *V) {
235 EnumerateType(V->getType());
236 if (const Constant *C = dyn_cast<Constant>(V)) {
237 // If this constant is already enumerated, ignore it, we know its type must
239 if (ValueMap.count(V)) return;
241 // This constant may have operands, make sure to enumerate the types in
243 for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
244 EnumerateOperandType(C->getOperand(i));
248 void ValueEnumerator::EnumerateParamAttrs(const ParamAttrsList *PAL) {
249 if (PAL == 0) return; // null is always 0.
251 unsigned &Entry = ParamAttrMap[PAL];
253 // Never saw this before, add it.
254 ParamAttrs.push_back(PAL);
255 Entry = ParamAttrs.size();
260 /// PurgeAggregateValues - If there are any aggregate values at the end of the
261 /// value list, remove them and return the count of the remaining values. If
262 /// there are none, return -1.
263 int ValueEnumerator::PurgeAggregateValues() {
264 // If there are no aggregate values at the end of the list, return -1.
265 if (Values.empty() || Values.back().first->getType()->isFirstClassType())
268 // Otherwise, remove aggregate values...
269 while (!Values.empty() && !Values.back().first->getType()->isFirstClassType())
272 // ... and return the new size.
273 return Values.size();
276 void ValueEnumerator::incorporateFunction(const Function &F) {
277 NumModuleValues = Values.size();
279 // Adding function arguments to the value table.
280 for(Function::const_arg_iterator I = F.arg_begin(), E = F.arg_end();
284 FirstFuncConstantID = Values.size();
286 // Add all function-level constants to the value table.
287 for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
288 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
289 for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
291 if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
295 BasicBlocks.push_back(BB);
296 ValueMap[BB] = BasicBlocks.size();
299 // Optimize the constant layout.
300 OptimizeConstants(FirstFuncConstantID, Values.size());
302 // Add the function's parameter attributes so they are available for use in
303 // the function's instruction.
304 EnumerateParamAttrs(F.getParamAttrs());
306 FirstInstID = Values.size();
308 // Add all of the instructions.
309 for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
310 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
311 if (I->getType() != Type::VoidTy)
317 void ValueEnumerator::purgeFunction() {
318 /// Remove purged values from the ValueMap.
319 for (unsigned i = NumModuleValues, e = Values.size(); i != e; ++i)
320 ValueMap.erase(Values[i].first);
321 for (unsigned i = 0, e = BasicBlocks.size(); i != e; ++i)
322 ValueMap.erase(BasicBlocks[i]);
324 Values.resize(NumModuleValues);