source: src/InitTweak/GenInit.cc@ 5f98ce5

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors ctor deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox memory new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since 5f98ce5 was 5f98ce5, checked in by Rob Schluntz <rschlunt@…>, 10 years ago

hoist non-constexpr array dimension into const variable in case of side effects
  • Property mode set to 100644
File size: 11.4 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// GenInit.cc --
8//
9// Author : Rob Schluntz
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Rob Schluntz
12// Last Modified On : Fri May 13 11:37:48 2016
13// Update Count : 166
14//
15
16#include <stack>
17#include <list>
18#include "GenInit.h"
19#include "InitTweak.h"
20#include "SynTree/Declaration.h"
21#include "SynTree/Type.h"
22#include "SynTree/Expression.h"
23#include "SynTree/Statement.h"
24#include "SynTree/Initializer.h"
25#include "SynTree/Mutator.h"
26#include "SymTab/Autogen.h"
27#include "GenPoly/PolyMutator.h"
28#include "GenPoly/DeclMutator.h"
29
30namespace InitTweak {
31 namespace {
32 const std::list<Label> noLabels;
33 const std::list<Expression *> noDesignators;
34 }
35
36 class ReturnFixer : public GenPoly::PolyMutator {
37 public:
38 /// consistently allocates a temporary variable for the return value
39 /// of a function so that anything which the resolver decides can be constructed
40 /// into the return type of a function can be returned.
41 static void makeReturnTemp( std::list< Declaration * > &translationUnit );
42
43 ReturnFixer();
44
45 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );
46
47 virtual Statement * mutate( ReturnStmt * returnStmt );
48
49 protected:
50 std::list<DeclarationWithType*> returnVals;
51 UniqueName tempNamer;
52 std::string funcName;
53 };
54
55 class CtorDtor : public GenPoly::PolyMutator {
56 public:
57 /// create constructor and destructor statements for object declarations.
58 /// the actual call statements will be added in after the resolver has run
59 /// so that the initializer expression is only removed if a constructor is found
60 /// and the same destructor call is inserted in all of the appropriate locations.
61 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
62
63 CtorDtor() : inFunction( false ) {}
64
65 virtual DeclarationWithType * mutate( ObjectDecl * );
66 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );
67 // should not traverse into any of these declarations to find objects
68 // that need to be constructed or destructed
69 virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
70 virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
71 virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
72 virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; }
73 virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; }
74 virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; }
75
76 virtual Type * mutate( FunctionType *funcType ) { return funcType; }
77
78 protected:
79 bool inFunction;
80 };
81
82 class HoistArrayDimension : public GenPoly::DeclMutator {
83 public:
84 typedef GenPoly::DeclMutator Parent;
85
86 /// hoist dimension from array types in object declaration so that it uses a single
87 /// const variable of type size_t, so that side effecting array dimensions are only
88 /// computed once.
89 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
90
91 private:
92 DeclarationWithType * mutate( ObjectDecl * objectDecl );
93 // should not traverse into any of these declarations to find objects
94 // that need to be constructed or destructed
95 virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
96 virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
97 virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
98 virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; }
99 virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; }
100 virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; }
101
102 virtual Type* mutate( FunctionType *funcType ) { return funcType; }
103
104 void hoist( Type * type );
105
106 DeclarationNode::StorageClass storageclass = DeclarationNode::NoStorageClass;
107 };
108
109 void genInit( std::list< Declaration * > & translationUnit ) {
110 ReturnFixer::makeReturnTemp( translationUnit );
111 HoistArrayDimension::hoistArrayDimension( translationUnit );
112 CtorDtor::generateCtorDtor( translationUnit );
113 }
114
115 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
116 ReturnFixer fixer;
117 mutateAll( translationUnit, fixer );
118 }
119
120 ReturnFixer::ReturnFixer() : tempNamer( "_retVal" ) {}
121
122 Statement *ReturnFixer::mutate( ReturnStmt *returnStmt ) {
123 // update for multiple return values
124 assert( returnVals.size() == 0 || returnVals.size() == 1 );
125 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
126 // is being returned
127 if ( returnStmt->get_expr() && returnVals.size() == 1 && funcName != "?=?" && ! returnVals.front()->get_type()->get_isLvalue() ) {
128 // ensure return value is not destructed by explicitly creating
129 // an empty SingleInit node wherein maybeConstruct is false
130 ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, returnVals.front()->get_type()->clone(), new ListInit( std::list<Initializer*>(), noDesignators, false ) );
131 stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) );
132
133 // and explicitly create the constructor expression separately
134 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
135 construct->get_args().push_back( new AddressExpr( new VariableExpr( newObj ) ) );
136 construct->get_args().push_back( returnStmt->get_expr() );
137 stmtsToAdd.push_back(new ExprStmt(noLabels, construct));
138
139 returnStmt->set_expr( new VariableExpr( newObj ) );
140 } // if
141 return returnStmt;
142 }
143
144 DeclarationWithType* ReturnFixer::mutate( FunctionDecl *functionDecl ) {
145 std::list<DeclarationWithType*> oldReturnVals = returnVals;
146 std::string oldFuncName = funcName;
147
148 FunctionType * type = functionDecl->get_functionType();
149 returnVals = type->get_returnVals();
150 funcName = functionDecl->get_name();
151 DeclarationWithType * decl = Mutator::mutate( functionDecl );
152 returnVals = oldReturnVals;
153 funcName = oldFuncName;
154 return decl;
155 }
156
157 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
158 HoistArrayDimension hoister;
159 mutateAll( translationUnit, hoister );
160 }
161
162 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
163 storageclass = objectDecl->get_storageClass();
164 DeclarationWithType * temp = Parent::mutate( objectDecl );
165 hoist( objectDecl->get_type() );
166 storageclass = DeclarationNode::NoStorageClass;
167 return temp;
168 }
169
170 void HoistArrayDimension::hoist( Type * type ) {
171 static UniqueName dimensionName( "_array_dim" );
172 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
173 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
174
175 // don't need to hoist dimension if it's a constexpr - only need to if there's potential
176 // for side effects.
177 if ( isConstExpr( arrayType->get_dimension() ) ) return;
178
179 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageclass, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
180 arrayDimension->get_type()->set_isConst( true );
181
182 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
183 addDeclaration( arrayDimension );
184
185 hoist( arrayType->get_base() );
186 return;
187 }
188 }
189
190 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
191 CtorDtor ctordtor;
192 mutateAll( translationUnit, ctordtor );
193 }
194
195 namespace {
196 Expression * makeCtorDtorExpr( std::string name, ObjectDecl * objDecl, std::list< Expression * > args ) {
197 UntypedExpr * expr = new UntypedExpr( new NameExpr( name ) );
198 expr->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) );
199 expr->get_args().splice( expr->get_args().end(), args );
200 return expr;
201 }
202 }
203
204 DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
205 // hands off if designated or if @=
206 if ( tryConstruct( objDecl ) ) {
207 if ( inFunction ) {
208 if ( ArrayType * at = dynamic_cast< ArrayType * >( objDecl->get_type() ) ) {
209 // call into makeArrayFunction from validate.cc to generate calls to ctor/dtor for each element of array
210 // TODO: walk initializers and generate appropriate ctor if element has initializer.
211 // Initializer could be nested (depends on the depth of the array type on the object)
212
213 std::list< Expression * > args = makeInitList( objDecl->get_init() );
214 if ( args.empty() ) {
215 std::list< Statement * > ctor;
216 std::list< Statement * > dtor;
217
218 SymTab::genImplicitCall( NULL, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
219 SymTab::genImplicitCall( NULL, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
220
221 // Currently genArrayCall produces a single Statement - a CompoundStmt
222 // which wraps everything that needs to happen. As such, it's technically
223 // possible to use a Statement ** in the above calls, but this is inherently
224 // unsafe, so instead we take the slightly less efficient route, but will be
225 // immediately informed if somehow the above assumption is broken. In this case,
226 // we could always wrap the list of statements at this point with a CompoundStmt,
227 // but it seems reasonable at the moment for this to be done by genArrayCall
228 // itself
229 assert( ctor.size() == 1 && dynamic_cast< ImplicitCtorDtorStmt * >( ctor.front() ) );
230 assert( dtor.size() == 1 && dynamic_cast< ImplicitCtorDtorStmt * >( dtor.front() ) );
231 objDecl->set_init( new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() ) );
232 } else {
233 // array came with an initializer list: initialize each element
234 // may have more initializers than elements in the array - need to check at each index that
235 // we haven't exceeded size. This requires precomputing the size because it might be a side-effecting
236 // computation.
237 // may have fewer initializers than elements in the array - need to default construct
238 // remaining elements.
239 // might be able to merge this with the case above.
240
241 }
242 } else {
243 // it's sufficient to attempt to call the ctor/dtor for the given object and its initializer
244 Expression * ctor = makeCtorDtorExpr( "?{}", objDecl, makeInitList( objDecl->get_init() ) );
245 Expression * dtor = makeCtorDtorExpr( "^?{}", objDecl, std::list< Expression * >() );
246
247 // need to remember init expression, in case no ctors exist
248 // if ctor does exist, want to use ctor expression instead of init
249 // push this decision to the resolver
250 ExprStmt * ctorStmt = new ExprStmt( noLabels, ctor );
251 ExprStmt * dtorStmt = new ExprStmt( noLabels, dtor );
252 objDecl->set_init( new ConstructorInit( new ImplicitCtorDtorStmt( ctorStmt ), new ImplicitCtorDtorStmt( dtorStmt ), objDecl->get_init() ) );
253 }
254 }
255 }
256 return Mutator::mutate( objDecl );
257 }
258
259 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
260 // parameters should not be constructed and destructed, so don't mutate FunctionType
261 bool oldInFunc = inFunction;
262 mutateAll( functionDecl->get_oldDecls(), *this );
263 inFunction = true;
264 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
265 inFunction = oldInFunc;
266 return functionDecl;
267 }
268} // namespace InitTweak
269
270// Local Variables: //
271// tab-width: 4 //
272// mode: c++ //
273// compile-command: "make install" //
274// End: //
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