source: src/InitTweak/GenInit.cc@ 3d4b23fa

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 3d4b23fa was 9ff56e7, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

Removed several new warnings
  • Property mode set to 100644
File size: 14.7 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
19#include "InitTweak.h"
20#include "GenInit.h"
21
22#include "Common/PassVisitor.h"
23
24#include "GenPoly/DeclMutator.h"
25#include "GenPoly/PolyMutator.h"
26#include "GenPoly/ScopedSet.h"
27
28#include "ResolvExpr/typeops.h"
29
30#include "SynTree/Declaration.h"
31#include "SynTree/Expression.h"
32#include "SynTree/Initializer.h"
33#include "SynTree/Mutator.h"
34#include "SynTree/Statement.h"
35#include "SynTree/Type.h"
36
37#include "SymTab/Autogen.h"
38#include "SymTab/Mangler.h"
39
40namespace InitTweak {
41 namespace {
42 const std::list<Label> noLabels;
43 const std::list<Expression *> noDesignators;
44 }
45
46 struct ReturnFixer : public WithStmtsToAdd, public WithGuards {
47 /// consistently allocates a temporary variable for the return value
48 /// of a function so that anything which the resolver decides can be constructed
49 /// into the return type of a function can be returned.
50 static void makeReturnTemp( std::list< Declaration * > &translationUnit );
51
52 void premutate( FunctionDecl *functionDecl );
53 void premutate( ReturnStmt * returnStmt );
54
55 protected:
56 FunctionType * ftype;
57 std::string funcName;
58 };
59
60 struct CtorDtor : public WithGuards, public WithShortCircuiting {
61 /// create constructor and destructor statements for object declarations.
62 /// the actual call statements will be added in after the resolver has run
63 /// so that the initializer expression is only removed if a constructor is found
64 /// and the same destructor call is inserted in all of the appropriate locations.
65 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
66
67 void previsit( ObjectDecl * );
68 void previsit( FunctionDecl *functionDecl );
69
70 // should not traverse into any of these declarations to find objects
71 // that need to be constructed or destructed
72 void previsit( StructDecl *aggregateDecl );
73 void previsit( __attribute__((unused)) UnionDecl * aggregateDecl ) { visit_children = false; }
74 void previsit( __attribute__((unused)) EnumDecl * aggregateDecl ) { visit_children = false; }
75 void previsit( __attribute__((unused)) TraitDecl * aggregateDecl ) { visit_children = false; }
76 void previsit( __attribute__((unused)) TypeDecl * typeDecl ) { visit_children = false; }
77 void previsit( __attribute__((unused)) TypedefDecl * typeDecl ) { visit_children = false; }
78 void previsit( __attribute__((unused)) FunctionType * funcType ) { visit_children = false; }
79
80 void previsit( CompoundStmt * compoundStmt );
81
82 private:
83 // set of mangled type names for which a constructor or destructor exists in the current scope.
84 // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
85 // should not have a ConstructorInit generated.
86
87 bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
88 bool isManaged( Type * type ) const; // determine if type is managed
89 void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
90 GenPoly::ScopedSet< std::string > managedTypes;
91 bool inFunction = false;
92 };
93
94 class HoistArrayDimension final : public GenPoly::DeclMutator {
95 public:
96 typedef GenPoly::DeclMutator Parent;
97
98 /// hoist dimension from array types in object declaration so that it uses a single
99 /// const variable of type size_t, so that side effecting array dimensions are only
100 /// computed once.
101 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
102
103 private:
104 using Parent::mutate;
105
106 virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
107 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
108 // should not traverse into any of these declarations to find objects
109 // that need to be constructed or destructed
110 virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
111 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
112 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
113 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
114 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
115 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
116
117 virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
118
119 void hoist( Type * type );
120
121 Type::StorageClasses storageClasses;
122 bool inFunction = false;
123 };
124
125 void genInit( std::list< Declaration * > & translationUnit ) {
126 ReturnFixer::makeReturnTemp( translationUnit );
127 HoistArrayDimension::hoistArrayDimension( translationUnit );
128 CtorDtor::generateCtorDtor( translationUnit );
129 }
130
131 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
132 PassVisitor<ReturnFixer> fixer;
133 mutateAll( translationUnit, fixer );
134 }
135
136 void ReturnFixer::premutate( ReturnStmt *returnStmt ) {
137 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
138 assert( returnVals.size() == 0 || returnVals.size() == 1 );
139 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
140 // is being returned
141 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! returnVals.front()->get_type()->get_lvalue() ) {
142 // explicitly construct the return value using the return expression and the retVal object
143 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
144 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
145 construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
146 construct->get_args().push_back( returnStmt->get_expr() );
147 stmtsToAddBefore.push_back(new ExprStmt(noLabels, construct));
148
149 // return the retVal object
150 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
151 } // if
152 }
153
154 void ReturnFixer::premutate( FunctionDecl *functionDecl ) {
155 GuardValue( ftype );
156 GuardValue( funcName );
157
158 ftype = functionDecl->get_functionType();
159 funcName = functionDecl->get_name();
160 }
161
162 // precompute array dimension expression, because constructor generation may duplicate it,
163 // which would be incorrect if it is a side-effecting computation.
164 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
165 HoistArrayDimension hoister;
166 hoister.mutateDeclarationList( translationUnit );
167 }
168
169 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
170 storageClasses = objectDecl->get_storageClasses();
171 DeclarationWithType * temp = Parent::mutate( objectDecl );
172 hoist( objectDecl->get_type() );
173 return temp;
174 }
175
176 void HoistArrayDimension::hoist( Type * type ) {
177 // if in function, generate const size_t var
178 static UniqueName dimensionName( "_array_dim" );
179
180 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
181 if ( ! inFunction ) return;
182 if ( storageClasses.is_static ) return;
183
184 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
185 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
186
187 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
188 if ( isConstExpr( arrayType->get_dimension() ) ) return;
189
190 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
191 arrayDimension->get_type()->set_const( true );
192
193 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
194 addDeclaration( arrayDimension );
195
196 hoist( arrayType->get_base() );
197 return;
198 }
199 }
200
201 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
202 ValueGuard< bool > oldInFunc( inFunction );
203 inFunction = true;
204 DeclarationWithType * decl = Parent::mutate( functionDecl );
205 return decl;
206 }
207
208 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
209 PassVisitor<CtorDtor> ctordtor;
210 acceptAll( translationUnit, ctordtor );
211 }
212
213 bool CtorDtor::isManaged( Type * type ) const {
214 // need to clear and reset qualifiers when determining if a type is managed
215 ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
216 type->get_qualifiers() = Type::Qualifiers();
217 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
218 // tuple is also managed if any of its components are managed
219 if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
220 return true;
221 }
222 }
223 // 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)
224 return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
225 }
226
227 bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
228 Type * type = objDecl->get_type();
229 while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
230 type = at->get_base();
231 }
232 return isManaged( type );
233 }
234
235 void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
236 // if this function is a user-defined constructor or destructor, mark down the type as "managed"
237 if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
238 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
239 assert( ! params.empty() );
240 PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
241 managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
242 }
243 }
244
245 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
246 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
247 assertf( objDecl, "genCtorDtor passed null objDecl" );
248 std::list< Statement * > stmts;
249 InitExpander srcParam( maybeClone( arg ) );
250 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
251 assert( stmts.size() <= 1 );
252 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
253 }
254
255 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
256 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
257 // for each constructable object
258 std::list< Statement * > ctor;
259 std::list< Statement * > dtor;
260
261 InitExpander srcParam( objDecl->get_init() );
262 InitExpander nullParam( (Initializer *)NULL );
263 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
264 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
265
266 // Currently genImplicitCall produces a single Statement - a CompoundStmt
267 // which wraps everything that needs to happen. As such, it's technically
268 // possible to use a Statement ** in the above calls, but this is inherently
269 // unsafe, so instead we take the slightly less efficient route, but will be
270 // immediately informed if somehow the above assumption is broken. In this case,
271 // we could always wrap the list of statements at this point with a CompoundStmt,
272 // but it seems reasonable at the moment for this to be done by genImplicitCall
273 // itself. It is possible that genImplicitCall produces no statements (e.g. if
274 // an array type does not have a dimension). In this case, it's fine to ignore
275 // the object for the purposes of construction.
276 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
277 if ( ctor.size() == 1 ) {
278 // need to remember init expression, in case no ctors exist
279 // if ctor does exist, want to use ctor expression instead of init
280 // push this decision to the resolver
281 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
282 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
283 }
284 return nullptr;
285 }
286
287 void CtorDtor::previsit( ObjectDecl * objDecl ) {
288 handleDWT( objDecl );
289 // hands off if @=, extern, builtin, etc.
290 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
291 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
292 // constructed objects cannot be designated
293 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 );
294 // constructed objects should not have initializers nested too deeply
295 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
296
297 objDecl->set_init( genCtorInit( objDecl ) );
298 }
299 }
300
301 void CtorDtor::previsit( FunctionDecl *functionDecl ) {
302 GuardValue( inFunction );
303 inFunction = true;
304
305 handleDWT( functionDecl );
306
307 GuardScope( managedTypes );
308 // go through assertions and recursively add seen ctor/dtors
309 for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
310 for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
311 handleDWT( assertion );
312 }
313 }
314
315 PassVisitor<CtorDtor> newCtorDtor;
316 newCtorDtor.pass = *this;
317 maybeAccept( functionDecl->get_statements(), newCtorDtor );
318 visit_children = false; // do not try and construct parameters or forall parameters - must happen after maybeAccept
319 }
320
321 void CtorDtor::previsit( StructDecl *aggregateDecl ) {
322 visit_children = false; // do not try to construct and destruct aggregate members
323
324 // don't construct members, but need to take note if there is a managed member,
325 // because that means that this type is also managed
326 for ( Declaration * member : aggregateDecl->get_members() ) {
327 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
328 if ( isManaged( field ) ) {
329 StructInstType inst( Type::Qualifiers(), aggregateDecl );
330 managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
331 break;
332 }
333 }
334 }
335 }
336
337 void CtorDtor::previsit( __attribute__((unused)) CompoundStmt * compoundStmt ) {
338 GuardScope( managedTypes );
339 }
340} // namespace InitTweak
341
342// Local Variables: //
343// tab-width: 4 //
344// mode: c++ //
345// compile-command: "make install" //
346// End: //
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