source: src/InitTweak/GenInit.cc@ 64bc131

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox 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 64bc131 was a28bc02, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

assignment argument and return value are now always copy constructed
  • Property mode set to 100644
File size: 15.1 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 : Peter A. Buhr
12// Last Modified On : Fri Mar 17 09:12:36 2017
13// Update Count : 183
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 "SymTab/Mangler.h"
28#include "GenPoly/PolyMutator.h"
29#include "GenPoly/DeclMutator.h"
30#include "GenPoly/ScopedSet.h"
31#include "ResolvExpr/typeops.h"
32
33namespace InitTweak {
34 namespace {
35 const std::list<Label> noLabels;
36 const std::list<Expression *> noDesignators;
37 }
38
39 class ReturnFixer final : public GenPoly::PolyMutator {
40 public:
41 /// consistently allocates a temporary variable for the return value
42 /// of a function so that anything which the resolver decides can be constructed
43 /// into the return type of a function can be returned.
44 static void makeReturnTemp( std::list< Declaration * > &translationUnit );
45
46 ReturnFixer();
47
48 typedef GenPoly::PolyMutator Parent;
49 using Parent::mutate;
50 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
51 virtual Statement * mutate( ReturnStmt * returnStmt ) override;
52
53 protected:
54 FunctionType * ftype;
55 std::string funcName;
56 };
57
58 class CtorDtor final : public GenPoly::PolyMutator {
59 public:
60 typedef GenPoly::PolyMutator Parent;
61 using Parent::mutate;
62 /// create constructor and destructor statements for object declarations.
63 /// the actual call statements will be added in after the resolver has run
64 /// so that the initializer expression is only removed if a constructor is found
65 /// and the same destructor call is inserted in all of the appropriate locations.
66 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
67
68 virtual DeclarationWithType * mutate( ObjectDecl * ) override;
69 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
70 // should not traverse into any of these declarations to find objects
71 // that need to be constructed or destructed
72 virtual Declaration* mutate( StructDecl *aggregateDecl ) override;
73 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
74 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
75 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
76 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
77 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
78
79 virtual Type * mutate( FunctionType *funcType ) override { return funcType; }
80
81 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt ) override;
82
83 private:
84 // set of mangled type names for which a constructor or destructor exists in the current scope.
85 // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
86 // should not have a ConstructorInit generated.
87
88 bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
89 bool isManaged( Type * type ) const; // determine if type is managed
90 void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
91 GenPoly::ScopedSet< std::string > managedTypes;
92 bool inFunction = false;
93 };
94
95 class HoistArrayDimension final : public GenPoly::DeclMutator {
96 public:
97 typedef GenPoly::DeclMutator Parent;
98
99 /// hoist dimension from array types in object declaration so that it uses a single
100 /// const variable of type size_t, so that side effecting array dimensions are only
101 /// computed once.
102 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
103
104 private:
105 using Parent::mutate;
106
107 virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
108 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
109 // should not traverse into any of these declarations to find objects
110 // that need to be constructed or destructed
111 virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
112 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
113 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
114 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
115 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
116 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
117
118 virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
119
120 void hoist( Type * type );
121
122 Type::StorageClasses storageClasses;
123 bool inFunction = false;
124 };
125
126 void genInit( std::list< Declaration * > & translationUnit ) {
127 ReturnFixer::makeReturnTemp( translationUnit );
128 HoistArrayDimension::hoistArrayDimension( translationUnit );
129 CtorDtor::generateCtorDtor( translationUnit );
130 }
131
132 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
133 ReturnFixer fixer;
134 mutateAll( translationUnit, fixer );
135 }
136
137 ReturnFixer::ReturnFixer() {}
138
139 Statement *ReturnFixer::mutate( ReturnStmt *returnStmt ) {
140 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
141 assert( returnVals.size() == 0 || returnVals.size() == 1 );
142 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
143 // is being returned
144 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! returnVals.front()->get_type()->get_lvalue() ) {
145 // explicitly construct the return value using the return expression and the retVal object
146 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
147 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
148 construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
149 construct->get_args().push_back( returnStmt->get_expr() );
150 stmtsToAdd.push_back(new ExprStmt(noLabels, construct));
151
152 // return the retVal object
153 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
154 } // if
155 return returnStmt;
156 }
157
158 DeclarationWithType* ReturnFixer::mutate( FunctionDecl *functionDecl ) {
159 ValueGuard< FunctionType * > oldFtype( ftype );
160 ValueGuard< std::string > oldFuncName( funcName );
161
162 ftype = functionDecl->get_functionType();
163 funcName = functionDecl->get_name();
164 return Parent::mutate( functionDecl );
165 }
166
167 // precompute array dimension expression, because constructor generation may duplicate it,
168 // which would be incorrect if it is a side-effecting computation.
169 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
170 HoistArrayDimension hoister;
171 hoister.mutateDeclarationList( translationUnit );
172 }
173
174 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
175 storageClasses = objectDecl->get_storageClasses();
176 DeclarationWithType * temp = Parent::mutate( objectDecl );
177 hoist( objectDecl->get_type() );
178 return temp;
179 }
180
181 void HoistArrayDimension::hoist( Type * type ) {
182 // if in function, generate const size_t var
183 static UniqueName dimensionName( "_array_dim" );
184
185 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
186 if ( ! inFunction ) return;
187 if ( storageClasses.is_static ) return;
188
189 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
190 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
191
192 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
193 if ( isConstExpr( arrayType->get_dimension() ) ) return;
194
195 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
196 arrayDimension->get_type()->set_const( true );
197
198 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
199 addDeclaration( arrayDimension );
200
201 hoist( arrayType->get_base() );
202 return;
203 }
204 }
205
206 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
207 ValueGuard< bool > oldInFunc( inFunction );
208 inFunction = true;
209 DeclarationWithType * decl = Parent::mutate( functionDecl );
210 return decl;
211 }
212
213 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
214 CtorDtor ctordtor;
215 mutateAll( translationUnit, ctordtor );
216 }
217
218 bool CtorDtor::isManaged( Type * type ) const {
219 // need to clear and reset qualifiers when determining if a type is managed
220 ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
221 type->get_qualifiers() = Type::Qualifiers();
222 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
223 // tuple is also managed if any of its components are managed
224 if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
225 return true;
226 }
227 }
228 // a type is managed if it appears in the map of known managed types, or if it contains any polymorphism (is a type variable or generic type containing a type variable)
229 return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
230 }
231
232 bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
233 Type * type = objDecl->get_type();
234 while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
235 type = at->get_base();
236 }
237 return isManaged( type );
238 }
239
240 void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
241 // if this function is a user-defined constructor or destructor, mark down the type as "managed"
242 if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
243 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
244 assert( ! params.empty() );
245 PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
246 managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
247 }
248 }
249
250 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
251 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
252 assertf( objDecl, "genCtorDtor passed null objDecl" );
253 std::list< Statement * > stmts;
254 InitExpander srcParam( maybeClone( arg ) );
255 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
256 assert( stmts.size() <= 1 );
257 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
258 }
259
260 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
261 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
262 // for each constructable object
263 std::list< Statement * > ctor;
264 std::list< Statement * > dtor;
265
266 InitExpander srcParam( objDecl->get_init() );
267 InitExpander nullParam( (Initializer *)NULL );
268 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
269 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
270
271 // Currently genImplicitCall produces a single Statement - a CompoundStmt
272 // which wraps everything that needs to happen. As such, it's technically
273 // possible to use a Statement ** in the above calls, but this is inherently
274 // unsafe, so instead we take the slightly less efficient route, but will be
275 // immediately informed if somehow the above assumption is broken. In this case,
276 // we could always wrap the list of statements at this point with a CompoundStmt,
277 // but it seems reasonable at the moment for this to be done by genImplicitCall
278 // itself. It is possible that genImplicitCall produces no statements (e.g. if
279 // an array type does not have a dimension). In this case, it's fine to ignore
280 // the object for the purposes of construction.
281 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
282 if ( ctor.size() == 1 ) {
283 // need to remember init expression, in case no ctors exist
284 // if ctor does exist, want to use ctor expression instead of init
285 // push this decision to the resolver
286 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
287 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
288 }
289 return nullptr;
290 }
291
292 DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
293 handleDWT( objDecl );
294 // hands off if @=, extern, builtin, etc.
295 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
296 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
297 // constructed objects cannot be designated
298 if ( isDesignated( objDecl->get_init() ) ) throw SemanticError( "Cannot include designations in the initializer for a managed Object. If this is really what you want, then initialize with @=.\n", objDecl );
299 // constructed objects should not have initializers nested too deeply
300 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
301
302 objDecl->set_init( genCtorInit( objDecl ) );
303 }
304 return Parent::mutate( objDecl );
305 }
306
307 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
308 ValueGuard< bool > oldInFunc = inFunction;
309 inFunction = true;
310
311 handleDWT( functionDecl );
312
313 managedTypes.beginScope();
314 // go through assertions and recursively add seen ctor/dtors
315 for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
316 for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
317 assertion = assertion->acceptMutator( *this );
318 }
319 }
320 // parameters should not be constructed and destructed, so don't mutate FunctionType
321 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
322
323 managedTypes.endScope();
324 return functionDecl;
325 }
326
327 Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) {
328 // don't construct members, but need to take note if there is a managed member,
329 // because that means that this type is also managed
330 for ( Declaration * member : aggregateDecl->get_members() ) {
331 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
332 if ( isManaged( field ) ) {
333 StructInstType inst( Type::Qualifiers(), aggregateDecl );
334 managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
335 break;
336 }
337 }
338 }
339 return aggregateDecl;
340 }
341
342 CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
343 managedTypes.beginScope();
344 CompoundStmt * stmt = Parent::mutate( compoundStmt );
345 managedTypes.endScope();
346 return stmt;
347 }
348
349} // namespace InitTweak
350
351// Local Variables: //
352// tab-width: 4 //
353// mode: c++ //
354// compile-command: "make install" //
355// End: //
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