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/Module.h"
18 #include "llvm/TypeSymbolTable.h"
19 #include "llvm/ValueSymbolTable.h"
20 #include "llvm/Instructions.h"
24 static bool isSingleValueType(const std::pair
<const llvm::Type
*,
26 return P
.first
->isSingleValueType();
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 EnumerateAttributes(cast
<Function
>(I
)->getAttributes());
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 EnumerateAttributes(CI
->getAttributes());
94 else if (const InvokeInst
*II
= dyn_cast
<InvokeInst
>(I
))
95 EnumerateAttributes(II
->getAttributes());
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 single-value 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(), isSingleValueType
);
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.
118 struct CstSortPredicate
{
120 explicit CstSortPredicate(ValueEnumerator
&ve
) : VE(ve
) {}
121 bool operator()(const std::pair
<const Value
*, unsigned> &LHS
,
122 const std::pair
<const Value
*, unsigned> &RHS
) {
124 if (LHS
.first
->getType() != RHS
.first
->getType())
125 return VE
.getTypeID(LHS
.first
->getType()) <
126 VE
.getTypeID(RHS
.first
->getType());
127 // Then by frequency.
128 return LHS
.second
> RHS
.second
;
133 /// OptimizeConstants - Reorder constant pool for denser encoding.
134 void ValueEnumerator::OptimizeConstants(unsigned CstStart
, unsigned CstEnd
) {
135 if (CstStart
== CstEnd
|| CstStart
+1 == CstEnd
) return;
137 CstSortPredicate
P(*this);
138 std::stable_sort(Values
.begin()+CstStart
, Values
.begin()+CstEnd
, P
);
140 // Ensure that integer constants are at the start of the constant pool. This
141 // is important so that GEP structure indices come before gep constant exprs.
142 std::partition(Values
.begin()+CstStart
, Values
.begin()+CstEnd
,
145 // Rebuild the modified portion of ValueMap.
146 for (; CstStart
!= CstEnd
; ++CstStart
)
147 ValueMap
[Values
[CstStart
].first
] = CstStart
+1;
151 /// EnumerateTypeSymbolTable - Insert all of the types in the specified symbol
153 void ValueEnumerator::EnumerateTypeSymbolTable(const TypeSymbolTable
&TST
) {
154 for (TypeSymbolTable::const_iterator TI
= TST
.begin(), TE
= TST
.end();
156 EnumerateType(TI
->second
);
159 /// EnumerateValueSymbolTable - Insert all of the values in the specified symbol
160 /// table into the values table.
161 void ValueEnumerator::EnumerateValueSymbolTable(const ValueSymbolTable
&VST
) {
162 for (ValueSymbolTable::const_iterator VI
= VST
.begin(), VE
= VST
.end();
164 EnumerateValue(VI
->getValue());
167 void ValueEnumerator::EnumerateValue(const Value
*V
) {
168 assert(V
->getType() != Type::VoidTy
&& "Can't insert void values!");
170 // Check to see if it's already in!
171 unsigned &ValueID
= ValueMap
[V
];
173 // Increment use count.
174 Values
[ValueID
-1].second
++;
178 // Enumerate the type of this value.
179 EnumerateType(V
->getType());
181 if (const Constant
*C
= dyn_cast
<Constant
>(V
)) {
182 if (isa
<GlobalValue
>(C
)) {
183 // Initializers for globals are handled explicitly elsewhere.
184 } else if (isa
<ConstantArray
>(C
) && cast
<ConstantArray
>(C
)->isString()) {
185 // Do not enumerate the initializers for an array of simple characters.
186 // The initializers just polute the value table, and we emit the strings
188 } else if (C
->getNumOperands()) {
189 // If a constant has operands, enumerate them. This makes sure that if a
190 // constant has uses (for example an array of const ints), that they are
193 // We prefer to enumerate them with values before we enumerate the user
194 // itself. This makes it more likely that we can avoid forward references
195 // in the reader. We know that there can be no cycles in the constants
196 // graph that don't go through a global variable.
197 for (User::const_op_iterator I
= C
->op_begin(), E
= C
->op_end();
201 // Finally, add the value. Doing this could make the ValueID reference be
202 // dangling, don't reuse it.
203 Values
.push_back(std::make_pair(V
, 1U));
204 ValueMap
[V
] = Values
.size();
210 Values
.push_back(std::make_pair(V
, 1U));
211 ValueID
= Values
.size();
215 void ValueEnumerator::EnumerateType(const Type
*Ty
) {
216 unsigned &TypeID
= TypeMap
[Ty
];
219 // If we've already seen this type, just increase its occurrence count.
220 Types
[TypeID
-1].second
++;
224 // First time we saw this type, add it.
225 Types
.push_back(std::make_pair(Ty
, 1U));
226 TypeID
= Types
.size();
228 // Enumerate subtypes.
229 for (Type::subtype_iterator I
= Ty
->subtype_begin(), E
= Ty
->subtype_end();
234 // Enumerate the types for the specified value. If the value is a constant,
235 // walk through it, enumerating the types of the constant.
236 void ValueEnumerator::EnumerateOperandType(const Value
*V
) {
237 EnumerateType(V
->getType());
238 if (const Constant
*C
= dyn_cast
<Constant
>(V
)) {
239 // If this constant is already enumerated, ignore it, we know its type must
241 if (ValueMap
.count(V
)) return;
243 // This constant may have operands, make sure to enumerate the types in
245 for (unsigned i
= 0, e
= C
->getNumOperands(); i
!= e
; ++i
)
246 EnumerateOperandType(C
->getOperand(i
));
250 void ValueEnumerator::EnumerateAttributes(const AttrListPtr
&PAL
) {
251 if (PAL
.isEmpty()) return; // null is always 0.
253 unsigned &Entry
= AttributeMap
[PAL
.getRawPointer()];
255 // Never saw this before, add it.
256 Attributes
.push_back(PAL
);
257 Entry
= Attributes
.size();
262 /// PurgeAggregateValues - If there are any aggregate values at the end of the
263 /// value list, remove them and return the count of the remaining values. If
264 /// there are none, return -1.
265 int ValueEnumerator::PurgeAggregateValues() {
266 // If there are no aggregate values at the end of the list, return -1.
267 if (Values
.empty() || Values
.back().first
->getType()->isSingleValueType())
270 // Otherwise, remove aggregate values...
271 while (!Values
.empty() && !Values
.back().first
->getType()->isSingleValueType())
274 // ... and return the new size.
275 return Values
.size();
278 void ValueEnumerator::incorporateFunction(const Function
&F
) {
279 NumModuleValues
= Values
.size();
281 // Adding function arguments to the value table.
282 for(Function::const_arg_iterator I
= F
.arg_begin(), E
= F
.arg_end();
286 FirstFuncConstantID
= Values
.size();
288 // Add all function-level constants to the value table.
289 for (Function::const_iterator BB
= F
.begin(), E
= F
.end(); BB
!= E
; ++BB
) {
290 for (BasicBlock::const_iterator I
= BB
->begin(), E
= BB
->end(); I
!=E
; ++I
)
291 for (User::const_op_iterator OI
= I
->op_begin(), E
= I
->op_end();
293 if ((isa
<Constant
>(*OI
) && !isa
<GlobalValue
>(*OI
)) ||
297 BasicBlocks
.push_back(BB
);
298 ValueMap
[BB
] = BasicBlocks
.size();
301 // Optimize the constant layout.
302 OptimizeConstants(FirstFuncConstantID
, Values
.size());
304 // Add the function's parameter attributes so they are available for use in
305 // the function's instruction.
306 EnumerateAttributes(F
.getAttributes());
308 FirstInstID
= Values
.size();
310 // Add all of the instructions.
311 for (Function::const_iterator BB
= F
.begin(), E
= F
.end(); BB
!= E
; ++BB
) {
312 for (BasicBlock::const_iterator I
= BB
->begin(), E
= BB
->end(); I
!=E
; ++I
) {
313 if (I
->getType() != Type::VoidTy
)
319 void ValueEnumerator::purgeFunction() {
320 /// Remove purged values from the ValueMap.
321 for (unsigned i
= NumModuleValues
, e
= Values
.size(); i
!= e
; ++i
)
322 ValueMap
.erase(Values
[i
].first
);
323 for (unsigned i
= 0, e
= BasicBlocks
.size(); i
!= e
; ++i
)
324 ValueMap
.erase(BasicBlocks
[i
]);
326 Values
.resize(NumModuleValues
);