source: src/InitTweak/GenInit.cc@ fd344aa

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 fd344aa was bff227f, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Refactor operator predicates into OperatorTable.cc
  • 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#include "CodeGen/OperatorTable.h"
24
25#include "GenPoly/DeclMutator.h"
26#include "GenPoly/PolyMutator.h"
27#include "GenPoly/ScopedSet.h"
28
29#include "ResolvExpr/typeops.h"
30
31#include "SynTree/Declaration.h"
32#include "SynTree/Expression.h"
33#include "SynTree/Initializer.h"
34#include "SynTree/Mutator.h"
35#include "SynTree/Statement.h"
36#include "SynTree/Type.h"
37
38#include "SymTab/Autogen.h"
39#include "SymTab/Mangler.h"
40
41namespace InitTweak {
42 namespace {
43 const std::list<Label> noLabels;
44 const std::list<Expression *> noDesignators;
45 }
46
47 struct ReturnFixer : public WithStmtsToAdd, public WithGuards {
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 = nullptr;
58 std::string funcName;
59 };
60
61 struct CtorDtor : public WithGuards, public WithShortCircuiting {
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 void previsit( ObjectDecl * );
69 void previsit( FunctionDecl *functionDecl );
70
71 // should not traverse into any of these declarations to find objects
72 // that need to be constructed or destructed
73 void previsit( StructDecl *aggregateDecl );
74 void previsit( __attribute__((unused)) UnionDecl * aggregateDecl ) { visit_children = false; }
75 void previsit( __attribute__((unused)) EnumDecl * aggregateDecl ) { visit_children = false; }
76 void previsit( __attribute__((unused)) TraitDecl * aggregateDecl ) { visit_children = false; }
77 void previsit( __attribute__((unused)) TypeDecl * typeDecl ) { visit_children = false; }
78 void previsit( __attribute__((unused)) TypedefDecl * typeDecl ) { visit_children = false; }
79 void previsit( __attribute__((unused)) FunctionType * funcType ) { visit_children = false; }
80
81 void previsit( CompoundStmt * compoundStmt );
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 PassVisitor<ReturnFixer> fixer;
134 mutateAll( translationUnit, fixer );
135 }
136
137 void ReturnFixer::premutate( ReturnStmt *returnStmt ) {
138 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
139 assert( returnVals.size() == 0 || returnVals.size() == 1 );
140 // hands off if the function returns a reference - we don't want to allocate a temporary if a variable's address
141 // is being returned
142 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! dynamic_cast< ReferenceType * >( returnVals.front()->get_type() ) ) {
143 // explicitly construct the return value using the return expression and the retVal object
144 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
145
146 stmtsToAddBefore.push_back( genCtorDtor( "?{}", dynamic_cast< ObjectDecl *>( returnVals.front() ), returnStmt->get_expr() ) );
147
148 // return the retVal object
149 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
150 } // if
151 }
152
153 void ReturnFixer::premutate( FunctionDecl *functionDecl ) {
154 GuardValue( ftype );
155 GuardValue( funcName );
156
157 ftype = functionDecl->get_functionType();
158 funcName = functionDecl->get_name();
159 }
160
161 // precompute array dimension expression, because constructor generation may duplicate it,
162 // which would be incorrect if it is a side-effecting computation.
163 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
164 HoistArrayDimension hoister;
165 hoister.mutateDeclarationList( translationUnit );
166 }
167
168 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
169 storageClasses = objectDecl->get_storageClasses();
170 DeclarationWithType * temp = Parent::mutate( objectDecl );
171 hoist( objectDecl->get_type() );
172 return temp;
173 }
174
175 void HoistArrayDimension::hoist( Type * type ) {
176 // if in function, generate const size_t var
177 static UniqueName dimensionName( "_array_dim" );
178
179 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
180 if ( ! inFunction ) return;
181 if ( storageClasses.is_static ) return;
182
183 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
184 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
185
186 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
187 if ( isConstExpr( arrayType->get_dimension() ) ) return;
188
189 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
190 arrayDimension->get_type()->set_const( true );
191
192 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
193 addDeclaration( arrayDimension );
194
195 hoist( arrayType->get_base() );
196 return;
197 }
198 }
199
200 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
201 ValueGuard< bool > oldInFunc( inFunction );
202 inFunction = true;
203 DeclarationWithType * decl = Parent::mutate( functionDecl );
204 return decl;
205 }
206
207 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
208 PassVisitor<CtorDtor> ctordtor;
209 acceptAll( translationUnit, ctordtor );
210 }
211
212 bool CtorDtor::isManaged( Type * type ) const {
213 // at least for now, references are never constructed
214 if ( dynamic_cast< ReferenceType * >( type ) ) return false;
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() ) && CodeGen::isCtorDtor( dwt->get_name() ) ) {
239 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
240 assert( ! params.empty() );
241 Type * type = InitTweak::getPointerBase( params.front()->get_type() );
242 assert( type );
243 managedTypes.insert( SymTab::Mangler::mangle( type ) );
244 }
245 }
246
247 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
248 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
249 assertf( objDecl, "genCtorDtor passed null objDecl" );
250 std::list< Statement * > stmts;
251 InitExpander srcParam( maybeClone( arg ) );
252 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
253 assert( stmts.size() <= 1 );
254 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
255 }
256
257 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
258 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
259 // for each constructable object
260 std::list< Statement * > ctor;
261 std::list< Statement * > dtor;
262
263 InitExpander srcParam( objDecl->get_init() );
264 InitExpander nullParam( (Initializer *)NULL );
265 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
266 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
267
268 // Currently genImplicitCall produces a single Statement - a CompoundStmt
269 // which wraps everything that needs to happen. As such, it's technically
270 // possible to use a Statement ** in the above calls, but this is inherently
271 // unsafe, so instead we take the slightly less efficient route, but will be
272 // immediately informed if somehow the above assumption is broken. In this case,
273 // we could always wrap the list of statements at this point with a CompoundStmt,
274 // but it seems reasonable at the moment for this to be done by genImplicitCall
275 // itself. It is possible that genImplicitCall produces no statements (e.g. if
276 // an array type does not have a dimension). In this case, it's fine to ignore
277 // the object for the purposes of construction.
278 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
279 if ( ctor.size() == 1 ) {
280 // need to remember init expression, in case no ctors exist
281 // if ctor does exist, want to use ctor expression instead of init
282 // push this decision to the resolver
283 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
284 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
285 }
286 return nullptr;
287 }
288
289 void CtorDtor::previsit( ObjectDecl * objDecl ) {
290 handleDWT( objDecl );
291 // hands off if @=, extern, builtin, etc.
292 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
293 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
294 // constructed objects cannot be designated
295 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 );
296 // constructed objects should not have initializers nested too deeply
297 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
298
299 objDecl->set_init( genCtorInit( objDecl ) );
300 }
301 }
302
303 void CtorDtor::previsit( FunctionDecl *functionDecl ) {
304 GuardValue( inFunction );
305 inFunction = true;
306
307 handleDWT( functionDecl );
308
309 GuardScope( managedTypes );
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
317 PassVisitor<CtorDtor> newCtorDtor;
318 newCtorDtor.pass = *this;
319 maybeAccept( functionDecl->get_statements(), newCtorDtor );
320 visit_children = false; // do not try and construct parameters or forall parameters - must happen after maybeAccept
321 }
322
323 void CtorDtor::previsit( StructDecl *aggregateDecl ) {
324 visit_children = false; // do not try to construct and destruct aggregate members
325
326 // don't construct members, but need to take note if there is a managed member,
327 // because that means that this type is also managed
328 for ( Declaration * member : aggregateDecl->get_members() ) {
329 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
330 if ( isManaged( field ) ) {
331 StructInstType inst( Type::Qualifiers(), aggregateDecl );
332 managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
333 break;
334 }
335 }
336 }
337 }
338
339 void CtorDtor::previsit( __attribute__((unused)) CompoundStmt * compoundStmt ) {
340 GuardScope( managedTypes );
341 }
342} // namespace InitTweak
343
344// Local Variables: //
345// tab-width: 4 //
346// mode: c++ //
347// compile-command: "make install" //
348// End: //
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