source: src/InitTweak/GenInit.cc@ 667c7da

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 667c7da was 4eb31f2b, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

Added base clases for passes to improve ease of use of the pass visitor
  • Property mode set to 100644
File size: 14.8 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 "SynTree/Declaration.h"
25#include "SynTree/Expression.h"
26#include "SynTree/Initializer.h"
27#include "SynTree/Mutator.h"
28#include "SynTree/Statement.h"
29#include "SynTree/Type.h"
30
31#include "SymTab/Autogen.h"
32#include "SymTab/Mangler.h"
33
34#include "GenPoly/DeclMutator.h"
35#include "GenPoly/PolyMutator.h"
36#include "GenPoly/ScopedSet.h"
37
38#include "ResolvExpr/typeops.h"
39
40namespace InitTweak {
41 namespace {
42 const std::list<Label> noLabels;
43 const std::list<Expression *> noDesignators;
44 }
45
46 class ReturnFixer : public WithStmtsToAdd, public WithScopes {
47 public:
48 /// consistently allocates a temporary variable for the return value
49 /// of a function so that anything which the resolver decides can be constructed
50 /// into the return type of a function can be returned.
51 static void makeReturnTemp( std::list< Declaration * > &translationUnit );
52
53 void premutate( FunctionDecl *functionDecl );
54 void premutate( ReturnStmt * returnStmt );
55
56 protected:
57 FunctionType * ftype;
58 std::string funcName;
59 };
60
61 class CtorDtor final : public GenPoly::PolyMutator {
62 public:
63 typedef GenPoly::PolyMutator Parent;
64 using Parent::mutate;
65 /// create constructor and destructor statements for object declarations.
66 /// the actual call statements will be added in after the resolver has run
67 /// so that the initializer expression is only removed if a constructor is found
68 /// and the same destructor call is inserted in all of the appropriate locations.
69 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
70
71 virtual DeclarationWithType * mutate( ObjectDecl * ) override;
72 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
73 // should not traverse into any of these declarations to find objects
74 // that need to be constructed or destructed
75 virtual Declaration* mutate( StructDecl *aggregateDecl ) override;
76 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
77 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
78 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
79 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
80 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
81
82 virtual Type * mutate( FunctionType *funcType ) override { return funcType; }
83
84 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt ) override;
85
86 private:
87 // set of mangled type names for which a constructor or destructor exists in the current scope.
88 // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
89 // should not have a ConstructorInit generated.
90
91 bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
92 bool isManaged( Type * type ) const; // determine if type is managed
93 void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
94 GenPoly::ScopedSet< std::string > managedTypes;
95 bool inFunction = false;
96 };
97
98 class HoistArrayDimension final : public GenPoly::DeclMutator {
99 public:
100 typedef GenPoly::DeclMutator Parent;
101
102 /// hoist dimension from array types in object declaration so that it uses a single
103 /// const variable of type size_t, so that side effecting array dimensions are only
104 /// computed once.
105 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
106
107 private:
108 using Parent::mutate;
109
110 virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
111 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
112 // should not traverse into any of these declarations to find objects
113 // that need to be constructed or destructed
114 virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
115 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
116 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
117 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
118 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
119 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
120
121 virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
122
123 void hoist( Type * type );
124
125 Type::StorageClasses storageClasses;
126 bool inFunction = false;
127 };
128
129 void genInit( std::list< Declaration * > & translationUnit ) {
130 ReturnFixer::makeReturnTemp( translationUnit );
131 HoistArrayDimension::hoistArrayDimension( translationUnit );
132 CtorDtor::generateCtorDtor( translationUnit );
133 }
134
135 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
136 PassVisitor<ReturnFixer> fixer;
137 mutateAll( translationUnit, fixer );
138 }
139
140 void ReturnFixer::premutate( ReturnStmt *returnStmt ) {
141 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
142 assert( returnVals.size() == 0 || returnVals.size() == 1 );
143 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
144 // is being returned
145 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! returnVals.front()->get_type()->get_lvalue() ) {
146 // explicitly construct the return value using the return expression and the retVal object
147 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
148 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
149 construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
150 construct->get_args().push_back( returnStmt->get_expr() );
151 stmtsToAddBefore.push_back(new ExprStmt(noLabels, construct));
152
153 // return the retVal object
154 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
155 } // if
156 }
157
158 void ReturnFixer::premutate( FunctionDecl *functionDecl ) {
159 GuardValue( ftype );
160 GuardValue( funcName );
161
162 ftype = functionDecl->get_functionType();
163 funcName = functionDecl->get_name();
164 }
165
166 // precompute array dimension expression, because constructor generation may duplicate it,
167 // which would be incorrect if it is a side-effecting computation.
168 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
169 HoistArrayDimension hoister;
170 hoister.mutateDeclarationList( translationUnit );
171 }
172
173 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
174 storageClasses = objectDecl->get_storageClasses();
175 DeclarationWithType * temp = Parent::mutate( objectDecl );
176 hoist( objectDecl->get_type() );
177 return temp;
178 }
179
180 void HoistArrayDimension::hoist( Type * type ) {
181 // if in function, generate const size_t var
182 static UniqueName dimensionName( "_array_dim" );
183
184 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
185 if ( ! inFunction ) return;
186 if ( storageClasses.is_static ) return;
187
188 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
189 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
190
191 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
192 if ( isConstExpr( arrayType->get_dimension() ) ) return;
193
194 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
195 arrayDimension->get_type()->set_const( true );
196
197 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
198 addDeclaration( arrayDimension );
199
200 hoist( arrayType->get_base() );
201 return;
202 }
203 }
204
205 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
206 ValueGuard< bool > oldInFunc( inFunction );
207 inFunction = true;
208 DeclarationWithType * decl = Parent::mutate( functionDecl );
209 return decl;
210 }
211
212 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
213 CtorDtor ctordtor;
214 mutateAll( translationUnit, ctordtor );
215 }
216
217 bool CtorDtor::isManaged( Type * type ) const {
218 // need to clear and reset qualifiers when determining if a type is managed
219 ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
220 type->get_qualifiers() = Type::Qualifiers();
221 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
222 // tuple is also managed if any of its components are managed
223 if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
224 return true;
225 }
226 }
227 // 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)
228 return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
229 }
230
231 bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
232 Type * type = objDecl->get_type();
233 while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
234 type = at->get_base();
235 }
236 return isManaged( type );
237 }
238
239 void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
240 // if this function is a user-defined constructor or destructor, mark down the type as "managed"
241 if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
242 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
243 assert( ! params.empty() );
244 PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
245 managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
246 }
247 }
248
249 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
250 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
251 assertf( objDecl, "genCtorDtor passed null objDecl" );
252 std::list< Statement * > stmts;
253 InitExpander srcParam( maybeClone( arg ) );
254 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
255 assert( stmts.size() <= 1 );
256 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
257 }
258
259 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
260 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
261 // for each constructable object
262 std::list< Statement * > ctor;
263 std::list< Statement * > dtor;
264
265 InitExpander srcParam( objDecl->get_init() );
266 InitExpander nullParam( (Initializer *)NULL );
267 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
268 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
269
270 // Currently genImplicitCall produces a single Statement - a CompoundStmt
271 // which wraps everything that needs to happen. As such, it's technically
272 // possible to use a Statement ** in the above calls, but this is inherently
273 // unsafe, so instead we take the slightly less efficient route, but will be
274 // immediately informed if somehow the above assumption is broken. In this case,
275 // we could always wrap the list of statements at this point with a CompoundStmt,
276 // but it seems reasonable at the moment for this to be done by genImplicitCall
277 // itself. It is possible that genImplicitCall produces no statements (e.g. if
278 // an array type does not have a dimension). In this case, it's fine to ignore
279 // the object for the purposes of construction.
280 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
281 if ( ctor.size() == 1 ) {
282 // need to remember init expression, in case no ctors exist
283 // if ctor does exist, want to use ctor expression instead of init
284 // push this decision to the resolver
285 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
286 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
287 }
288 return nullptr;
289 }
290
291 DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
292 handleDWT( objDecl );
293 // hands off if @=, extern, builtin, etc.
294 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
295 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
296 // constructed objects cannot be designated
297 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 );
298 // constructed objects should not have initializers nested too deeply
299 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
300
301 objDecl->set_init( genCtorInit( objDecl ) );
302 }
303 return Parent::mutate( objDecl );
304 }
305
306 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
307 ValueGuard< bool > oldInFunc = inFunction;
308 inFunction = true;
309
310 handleDWT( functionDecl );
311
312 managedTypes.beginScope();
313 // go through assertions and recursively add seen ctor/dtors
314 for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
315 for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
316 handleDWT( assertion );
317 }
318 }
319 // parameters should not be constructed and destructed, so don't mutate FunctionType
320 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
321
322 managedTypes.endScope();
323 return functionDecl;
324 }
325
326 Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) {
327 // don't construct members, but need to take note if there is a managed member,
328 // because that means that this type is also managed
329 for ( Declaration * member : aggregateDecl->get_members() ) {
330 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
331 if ( isManaged( field ) ) {
332 StructInstType inst( Type::Qualifiers(), aggregateDecl );
333 managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
334 break;
335 }
336 }
337 }
338 return aggregateDecl;
339 }
340
341 CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
342 managedTypes.beginScope();
343 CompoundStmt * stmt = Parent::mutate( compoundStmt );
344 managedTypes.endScope();
345 return stmt;
346 }
347
348} // namespace InitTweak
349
350// Local Variables: //
351// tab-width: 4 //
352// mode: c++ //
353// compile-command: "make install" //
354// End: //
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