1 //===-- ValueEnumerator.cpp - Number values and types for bitcode writer --===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/MDNode.h"
18 #include "llvm/Module.h"
19 #include "llvm/TypeSymbolTable.h"
20 #include "llvm/ValueSymbolTable.h"
21 #include "llvm/Instructions.h"
25 static bool isSingleValueType(const std::pair<const llvm::Type*,
27 return P.first->isSingleValueType();
30 static bool isIntegerValue(const std::pair<const Value*, unsigned> &V) {
31 return isa<IntegerType>(V.first->getType());
34 static bool CompareByFrequency(const std::pair<const llvm::Type*,
36 const std::pair<const llvm::Type*,
38 return P1.second > P2.second;
41 /// ValueEnumerator - Enumerate module-level information.
42 ValueEnumerator::ValueEnumerator(const Module *M) {
43 // Enumerate the global variables.
44 for (Module::const_global_iterator I = M->global_begin(),
45 E = M->global_end(); I != E; ++I)
48 // Enumerate the functions.
49 for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
51 EnumerateAttributes(cast<Function>(I)->getAttributes());
54 // Enumerate the aliases.
55 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
59 // Remember what is the cutoff between globalvalue's and other constants.
60 unsigned FirstConstant = Values.size();
62 // Enumerate the global variable initializers.
63 for (Module::const_global_iterator I = M->global_begin(),
64 E = M->global_end(); I != E; ++I)
65 if (I->hasInitializer())
66 EnumerateValue(I->getInitializer());
68 // Enumerate the aliasees.
69 for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
71 EnumerateValue(I->getAliasee());
73 // Enumerate types used by the type symbol table.
74 EnumerateTypeSymbolTable(M->getTypeSymbolTable());
76 // Insert constants that are named at module level into the slot pool so that
77 // the module symbol table can refer to them...
78 EnumerateValueSymbolTable(M->getValueSymbolTable());
80 // Enumerate types used by function bodies and argument lists.
81 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
83 for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
85 EnumerateType(I->getType());
87 for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
88 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
89 for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
91 EnumerateOperandType(*OI);
92 EnumerateType(I->getType());
93 if (const CallInst *CI = dyn_cast<CallInst>(I))
94 EnumerateAttributes(CI->getAttributes());
95 else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
96 EnumerateAttributes(II->getAttributes());
100 // Optimize constant ordering.
101 OptimizeConstants(FirstConstant, Values.size());
103 // Sort the type table by frequency so that most commonly used types are early
104 // in the table (have low bit-width).
105 std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);
107 // Partition the Type ID's so that the single-value types occur before the
108 // aggregate types. This allows the aggregate types to be dropped from the
109 // type table after parsing the global variable initializers.
110 std::partition(Types.begin(), Types.end(), isSingleValueType);
112 // Now that we rearranged the type table, rebuild TypeMap.
113 for (unsigned i = 0, e = Types.size(); i != e; ++i)
114 TypeMap[Types[i].first] = i+1;
117 // Optimize constant ordering.
119 struct CstSortPredicate {
121 explicit CstSortPredicate(ValueEnumerator &ve) : VE(ve) {}
122 bool operator()(const std::pair<const Value*, unsigned> &LHS,
123 const std::pair<const Value*, unsigned> &RHS) {
125 if (LHS.first->getType() != RHS.first->getType())
126 return VE.getTypeID(LHS.first->getType()) <
127 VE.getTypeID(RHS.first->getType());
128 // Then by frequency.
129 return LHS.second > RHS.second;
134 /// OptimizeConstants - Reorder constant pool for denser encoding.
135 void ValueEnumerator::OptimizeConstants(unsigned CstStart, unsigned CstEnd) {
136 if (CstStart == CstEnd || CstStart+1 == CstEnd) return;
138 CstSortPredicate P(*this);
139 std::stable_sort(Values.begin()+CstStart, Values.begin()+CstEnd, P);
141 // Ensure that integer constants are at the start of the constant pool. This
142 // is important so that GEP structure indices come before gep constant exprs.
143 std::partition(Values.begin()+CstStart, Values.begin()+CstEnd,
146 // Rebuild the modified portion of ValueMap.
147 for (; CstStart != CstEnd; ++CstStart)
148 ValueMap[Values[CstStart].first] = CstStart+1;
152 /// EnumerateTypeSymbolTable - Insert all of the types in the specified symbol
154 void ValueEnumerator::EnumerateTypeSymbolTable(const TypeSymbolTable &TST) {
155 for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
157 EnumerateType(TI->second);
160 /// EnumerateValueSymbolTable - Insert all of the values in the specified symbol
161 /// table into the values table.
162 void ValueEnumerator::EnumerateValueSymbolTable(const ValueSymbolTable &VST) {
163 for (ValueSymbolTable::const_iterator VI = VST.begin(), VE = VST.end();
165 EnumerateValue(VI->getValue());
168 void ValueEnumerator::EnumerateValue(const Value *V) {
169 assert(V->getType() != Type::VoidTy && "Can't insert void values!");
171 // Check to see if it's already in!
172 unsigned &ValueID = ValueMap[V];
174 // Increment use count.
175 Values[ValueID-1].second++;
179 // Enumerate the type of this value.
180 EnumerateType(V->getType());
182 if (const Constant *C = dyn_cast<Constant>(V)) {
183 if (isa<GlobalValue>(C)) {
184 // Initializers for globals are handled explicitly elsewhere.
185 } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
186 // Do not enumerate the initializers for an array of simple characters.
187 // The initializers just polute the value table, and we emit the strings
189 } else if (C->getNumOperands()) {
190 // If a constant has operands, enumerate them. This makes sure that if a
191 // constant has uses (for example an array of const ints), that they are
194 // We prefer to enumerate them with values before we enumerate the user
195 // itself. This makes it more likely that we can avoid forward references
196 // in the reader. We know that there can be no cycles in the constants
197 // graph that don't go through a global variable.
198 for (User::const_op_iterator I = C->op_begin(), E = C->op_end();
202 // Finally, add the value. Doing this could make the ValueID reference be
203 // dangling, don't reuse it.
204 Values.push_back(std::make_pair(V, 1U));
205 ValueMap[V] = Values.size();
207 } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
208 for (MDNode::const_elem_iterator I = N->elem_begin(), E = N->elem_end();
213 EnumerateType(Type::VoidTy);
216 Values.push_back(std::make_pair(V, 1U));
217 ValueMap[V] = Values.size();
223 Values.push_back(std::make_pair(V, 1U));
224 ValueID = Values.size();
228 void ValueEnumerator::EnumerateType(const Type *Ty) {
229 unsigned &TypeID = TypeMap[Ty];
232 // If we've already seen this type, just increase its occurrence count.
233 Types[TypeID-1].second++;
237 // First time we saw this type, add it.
238 Types.push_back(std::make_pair(Ty, 1U));
239 TypeID = Types.size();
241 // Enumerate subtypes.
242 for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
247 // Enumerate the types for the specified value. If the value is a constant,
248 // walk through it, enumerating the types of the constant.
249 void ValueEnumerator::EnumerateOperandType(const Value *V) {
250 EnumerateType(V->getType());
251 if (const Constant *C = dyn_cast<Constant>(V)) {
252 // If this constant is already enumerated, ignore it, we know its type must
254 if (ValueMap.count(V)) return;
256 // This constant may have operands, make sure to enumerate the types in
258 for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
259 EnumerateOperandType(C->getOperand(i));
261 if (const MDNode *N = dyn_cast<MDNode>(V)) {
262 for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
263 Value *Elem = N->getElement(i);
265 EnumerateOperandType(Elem);
268 } else if (const MDString *MDS = dyn_cast<MDString>(V))
272 void ValueEnumerator::EnumerateAttributes(const AttrListPtr &PAL) {
273 if (PAL.isEmpty()) return; // null is always 0.
275 unsigned &Entry = AttributeMap[PAL.getRawPointer()];
277 // Never saw this before, add it.
278 Attributes.push_back(PAL);
279 Entry = Attributes.size();
284 void ValueEnumerator::incorporateFunction(const Function &F) {
285 NumModuleValues = Values.size();
287 // Adding function arguments to the value table.
288 for(Function::const_arg_iterator I = F.arg_begin(), E = F.arg_end();
292 FirstFuncConstantID = Values.size();
294 // Add all function-level constants to the value table.
295 for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
296 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
297 for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
299 if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
303 BasicBlocks.push_back(BB);
304 ValueMap[BB] = BasicBlocks.size();
307 // Optimize the constant layout.
308 OptimizeConstants(FirstFuncConstantID, Values.size());
310 // Add the function's parameter attributes so they are available for use in
311 // the function's instruction.
312 EnumerateAttributes(F.getAttributes());
314 FirstInstID = Values.size();
316 // Add all of the instructions.
317 for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
318 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
319 if (I->getType() != Type::VoidTy)
325 void ValueEnumerator::purgeFunction() {
326 /// Remove purged values from the ValueMap.
327 for (unsigned i = NumModuleValues, e = Values.size(); i != e; ++i)
328 ValueMap.erase(Values[i].first);
329 for (unsigned i = 0, e = BasicBlocks.size(); i != e; ++i)
330 ValueMap.erase(BasicBlocks[i]);
332 Values.resize(NumModuleValues);