source: src/InitTweak/GenInit.cc@ ac032b5

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 ac032b5 was 0db6fc0, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

convert several passes to PassVisitor
  • Property mode set to 100644
File size: 15.0 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 typedef GenPoly::PolyMutator Parent;
47 using Parent::mutate;
48 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
49 virtual Statement * mutate( ReturnStmt * returnStmt ) override;
50
51 protected:
52 FunctionType * ftype;
53 std::string funcName;
54 };
55
56 class CtorDtor final : public GenPoly::PolyMutator {
57 public:
58 typedef GenPoly::PolyMutator Parent;
59 using Parent::mutate;
60 /// create constructor and destructor statements for object declarations.
61 /// the actual call statements will be added in after the resolver has run
62 /// so that the initializer expression is only removed if a constructor is found
63 /// and the same destructor call is inserted in all of the appropriate locations.
64 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
65
66 virtual DeclarationWithType * mutate( ObjectDecl * ) override;
67 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
68 // should not traverse into any of these declarations to find objects
69 // that need to be constructed or destructed
70 virtual Declaration* mutate( StructDecl *aggregateDecl ) override;
71 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
72 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
73 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
74 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
75 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
76
77 virtual Type * mutate( FunctionType *funcType ) override { return funcType; }
78
79 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt ) override;
80
81 private:
82 // set of mangled type names for which a constructor or destructor exists in the current scope.
83 // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
84 // should not have a ConstructorInit generated.
85
86 bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
87 bool isManaged( Type * type ) const; // determine if type is managed
88 void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
89 GenPoly::ScopedSet< std::string > managedTypes;
90 bool inFunction = false;
91 };
92
93 class HoistArrayDimension final : public GenPoly::DeclMutator {
94 public:
95 typedef GenPoly::DeclMutator Parent;
96
97 /// hoist dimension from array types in object declaration so that it uses a single
98 /// const variable of type size_t, so that side effecting array dimensions are only
99 /// computed once.
100 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
101
102 private:
103 using Parent::mutate;
104
105 virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
106 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
107 // should not traverse into any of these declarations to find objects
108 // that need to be constructed or destructed
109 virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
110 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
111 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
112 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
113 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
114 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
115
116 virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
117
118 void hoist( Type * type );
119
120 Type::StorageClasses storageClasses;
121 bool inFunction = false;
122 };
123
124 void genInit( std::list< Declaration * > & translationUnit ) {
125 ReturnFixer::makeReturnTemp( translationUnit );
126 HoistArrayDimension::hoistArrayDimension( translationUnit );
127 CtorDtor::generateCtorDtor( translationUnit );
128 }
129
130 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
131 ReturnFixer fixer;
132 mutateAll( translationUnit, fixer );
133 }
134
135 Statement *ReturnFixer::mutate( ReturnStmt *returnStmt ) {
136 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
137 assert( returnVals.size() == 0 || returnVals.size() == 1 );
138 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
139 // is being returned
140 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! returnVals.front()->get_type()->get_lvalue() ) {
141 // explicitly construct the return value using the return expression and the retVal object
142 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
143 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
144 construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
145 construct->get_args().push_back( returnStmt->get_expr() );
146 stmtsToAdd.push_back(new ExprStmt(noLabels, construct));
147
148 // return the retVal object
149 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
150 } // if
151 return returnStmt;
152 }
153
154 DeclarationWithType* ReturnFixer::mutate( FunctionDecl *functionDecl ) {
155 ValueGuard< FunctionType * > oldFtype( ftype );
156 ValueGuard< std::string > oldFuncName( funcName );
157
158 ftype = functionDecl->get_functionType();
159 funcName = functionDecl->get_name();
160 return Parent::mutate( functionDecl );
161 }
162
163 // precompute array dimension expression, because constructor generation may duplicate it,
164 // which would be incorrect if it is a side-effecting computation.
165 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
166 HoistArrayDimension hoister;
167 hoister.mutateDeclarationList( translationUnit );
168 }
169
170 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
171 storageClasses = objectDecl->get_storageClasses();
172 DeclarationWithType * temp = Parent::mutate( objectDecl );
173 hoist( objectDecl->get_type() );
174 return temp;
175 }
176
177 void HoistArrayDimension::hoist( Type * type ) {
178 // if in function, generate const size_t var
179 static UniqueName dimensionName( "_array_dim" );
180
181 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
182 if ( ! inFunction ) return;
183 if ( storageClasses.is_static ) return;
184
185 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
186 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
187
188 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
189 if ( isConstExpr( arrayType->get_dimension() ) ) return;
190
191 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
192 arrayDimension->get_type()->set_const( true );
193
194 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
195 addDeclaration( arrayDimension );
196
197 hoist( arrayType->get_base() );
198 return;
199 }
200 }
201
202 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
203 ValueGuard< bool > oldInFunc( inFunction );
204 inFunction = true;
205 DeclarationWithType * decl = Parent::mutate( functionDecl );
206 return decl;
207 }
208
209 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
210 CtorDtor ctordtor;
211 mutateAll( translationUnit, ctordtor );
212 }
213
214 bool CtorDtor::isManaged( Type * type ) const {
215 // need to clear and reset qualifiers when determining if a type is managed
216 ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
217 type->get_qualifiers() = Type::Qualifiers();
218 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
219 // tuple is also managed if any of its components are managed
220 if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
221 return true;
222 }
223 }
224 // 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)
225 return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
226 }
227
228 bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
229 Type * type = objDecl->get_type();
230 while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
231 type = at->get_base();
232 }
233 return isManaged( type );
234 }
235
236 void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
237 // if this function is a user-defined constructor or destructor, mark down the type as "managed"
238 if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
239 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
240 assert( ! params.empty() );
241 PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
242 managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
243 }
244 }
245
246 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
247 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
248 assertf( objDecl, "genCtorDtor passed null objDecl" );
249 std::list< Statement * > stmts;
250 InitExpander srcParam( maybeClone( arg ) );
251 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
252 assert( stmts.size() <= 1 );
253 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
254 }
255
256 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
257 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
258 // for each constructable object
259 std::list< Statement * > ctor;
260 std::list< Statement * > dtor;
261
262 InitExpander srcParam( objDecl->get_init() );
263 InitExpander nullParam( (Initializer *)NULL );
264 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
265 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
266
267 // Currently genImplicitCall produces a single Statement - a CompoundStmt
268 // which wraps everything that needs to happen. As such, it's technically
269 // possible to use a Statement ** in the above calls, but this is inherently
270 // unsafe, so instead we take the slightly less efficient route, but will be
271 // immediately informed if somehow the above assumption is broken. In this case,
272 // we could always wrap the list of statements at this point with a CompoundStmt,
273 // but it seems reasonable at the moment for this to be done by genImplicitCall
274 // itself. It is possible that genImplicitCall produces no statements (e.g. if
275 // an array type does not have a dimension). In this case, it's fine to ignore
276 // the object for the purposes of construction.
277 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
278 if ( ctor.size() == 1 ) {
279 // need to remember init expression, in case no ctors exist
280 // if ctor does exist, want to use ctor expression instead of init
281 // push this decision to the resolver
282 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
283 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
284 }
285 return nullptr;
286 }
287
288 DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
289 handleDWT( objDecl );
290 // hands off if @=, extern, builtin, etc.
291 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
292 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
293 // constructed objects cannot be designated
294 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 );
295 // constructed objects should not have initializers nested too deeply
296 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
297
298 objDecl->set_init( genCtorInit( objDecl ) );
299 }
300 return Parent::mutate( objDecl );
301 }
302
303 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
304 ValueGuard< bool > oldInFunc = inFunction;
305 inFunction = true;
306
307 handleDWT( functionDecl );
308
309 managedTypes.beginScope();
310 // go through assertions and recursively add seen ctor/dtors
311 for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
312 for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
313 handleDWT( assertion );
314 }
315 }
316 // parameters should not be constructed and destructed, so don't mutate FunctionType
317 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
318
319 managedTypes.endScope();
320 return functionDecl;
321 }
322
323 Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) {
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 return aggregateDecl;
336 }
337
338 CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
339 managedTypes.beginScope();
340 CompoundStmt * stmt = Parent::mutate( compoundStmt );
341 managedTypes.endScope();
342 return stmt;
343 }
344
345} // namespace InitTweak
346
347// Local Variables: //
348// tab-width: 4 //
349// mode: c++ //
350// compile-command: "make install" //
351// End: //
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