source: src/InitTweak/GenInit.cc@ 974bcdd

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 974bcdd was 7b6ca2e, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

move ReturnFixer to PassVisitor (uses GuardValue)
  • Property mode set to 100644
File size: 14.9 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 {
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 at_cleanup_t at_cleanup;
57 std::list< Statement * > stmtsToAddBefore;
58
59 protected:
60 FunctionType * ftype;
61 std::string funcName;
62 };
63
64 class CtorDtor final : public GenPoly::PolyMutator {
65 public:
66 typedef GenPoly::PolyMutator Parent;
67 using Parent::mutate;
68 /// create constructor and destructor statements for object declarations.
69 /// the actual call statements will be added in after the resolver has run
70 /// so that the initializer expression is only removed if a constructor is found
71 /// and the same destructor call is inserted in all of the appropriate locations.
72 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
73
74 virtual DeclarationWithType * mutate( ObjectDecl * ) override;
75 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
76 // should not traverse into any of these declarations to find objects
77 // that need to be constructed or destructed
78 virtual Declaration* mutate( StructDecl *aggregateDecl ) override;
79 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
80 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
81 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
82 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
83 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
84
85 virtual Type * mutate( FunctionType *funcType ) override { return funcType; }
86
87 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt ) override;
88
89 private:
90 // set of mangled type names for which a constructor or destructor exists in the current scope.
91 // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
92 // should not have a ConstructorInit generated.
93
94 bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
95 bool isManaged( Type * type ) const; // determine if type is managed
96 void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
97 GenPoly::ScopedSet< std::string > managedTypes;
98 bool inFunction = false;
99 };
100
101 class HoistArrayDimension final : public GenPoly::DeclMutator {
102 public:
103 typedef GenPoly::DeclMutator Parent;
104
105 /// hoist dimension from array types in object declaration so that it uses a single
106 /// const variable of type size_t, so that side effecting array dimensions are only
107 /// computed once.
108 static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
109
110 private:
111 using Parent::mutate;
112
113 virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
114 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
115 // should not traverse into any of these declarations to find objects
116 // that need to be constructed or destructed
117 virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
118 virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
119 virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
120 virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
121 virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
122 virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
123
124 virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
125
126 void hoist( Type * type );
127
128 Type::StorageClasses storageClasses;
129 bool inFunction = false;
130 };
131
132 void genInit( std::list< Declaration * > & translationUnit ) {
133 ReturnFixer::makeReturnTemp( translationUnit );
134 HoistArrayDimension::hoistArrayDimension( translationUnit );
135 CtorDtor::generateCtorDtor( translationUnit );
136 }
137
138 void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
139 PassVisitor<ReturnFixer> fixer;
140 mutateAll( translationUnit, fixer );
141 }
142
143 void ReturnFixer::premutate( ReturnStmt *returnStmt ) {
144 std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
145 assert( returnVals.size() == 0 || returnVals.size() == 1 );
146 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
147 // is being returned
148 if ( returnStmt->get_expr() && returnVals.size() == 1 && ! returnVals.front()->get_type()->get_lvalue() ) {
149 // explicitly construct the return value using the return expression and the retVal object
150 assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
151 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
152 construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
153 construct->get_args().push_back( returnStmt->get_expr() );
154 stmtsToAddBefore.push_back(new ExprStmt(noLabels, construct));
155
156 // return the retVal object
157 returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
158 } // if
159 }
160
161 void ReturnFixer::premutate( FunctionDecl *functionDecl ) {
162 GuardValue( this, ftype );
163 GuardValue( this, funcName );
164
165 ftype = functionDecl->get_functionType();
166 funcName = functionDecl->get_name();
167 }
168
169 // precompute array dimension expression, because constructor generation may duplicate it,
170 // which would be incorrect if it is a side-effecting computation.
171 void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
172 HoistArrayDimension hoister;
173 hoister.mutateDeclarationList( translationUnit );
174 }
175
176 DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
177 storageClasses = objectDecl->get_storageClasses();
178 DeclarationWithType * temp = Parent::mutate( objectDecl );
179 hoist( objectDecl->get_type() );
180 return temp;
181 }
182
183 void HoistArrayDimension::hoist( Type * type ) {
184 // if in function, generate const size_t var
185 static UniqueName dimensionName( "_array_dim" );
186
187 // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
188 if ( ! inFunction ) return;
189 if ( storageClasses.is_static ) return;
190
191 if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
192 if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
193
194 // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
195 if ( isConstExpr( arrayType->get_dimension() ) ) return;
196
197 ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
198 arrayDimension->get_type()->set_const( true );
199
200 arrayType->set_dimension( new VariableExpr( arrayDimension ) );
201 addDeclaration( arrayDimension );
202
203 hoist( arrayType->get_base() );
204 return;
205 }
206 }
207
208 DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
209 ValueGuard< bool > oldInFunc( inFunction );
210 inFunction = true;
211 DeclarationWithType * decl = Parent::mutate( functionDecl );
212 return decl;
213 }
214
215 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
216 CtorDtor ctordtor;
217 mutateAll( translationUnit, ctordtor );
218 }
219
220 bool CtorDtor::isManaged( Type * type ) const {
221 // need to clear and reset qualifiers when determining if a type is managed
222 ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
223 type->get_qualifiers() = Type::Qualifiers();
224 if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
225 // tuple is also managed if any of its components are managed
226 if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
227 return true;
228 }
229 }
230 // 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)
231 return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
232 }
233
234 bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
235 Type * type = objDecl->get_type();
236 while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
237 type = at->get_base();
238 }
239 return isManaged( type );
240 }
241
242 void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
243 // if this function is a user-defined constructor or destructor, mark down the type as "managed"
244 if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
245 std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
246 assert( ! params.empty() );
247 PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
248 managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
249 }
250 }
251
252 ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
253 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
254 assertf( objDecl, "genCtorDtor passed null objDecl" );
255 std::list< Statement * > stmts;
256 InitExpander srcParam( maybeClone( arg ) );
257 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
258 assert( stmts.size() <= 1 );
259 return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
260 }
261
262 ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
263 // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
264 // for each constructable object
265 std::list< Statement * > ctor;
266 std::list< Statement * > dtor;
267
268 InitExpander srcParam( objDecl->get_init() );
269 InitExpander nullParam( (Initializer *)NULL );
270 SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
271 SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
272
273 // Currently genImplicitCall produces a single Statement - a CompoundStmt
274 // which wraps everything that needs to happen. As such, it's technically
275 // possible to use a Statement ** in the above calls, but this is inherently
276 // unsafe, so instead we take the slightly less efficient route, but will be
277 // immediately informed if somehow the above assumption is broken. In this case,
278 // we could always wrap the list of statements at this point with a CompoundStmt,
279 // but it seems reasonable at the moment for this to be done by genImplicitCall
280 // itself. It is possible that genImplicitCall produces no statements (e.g. if
281 // an array type does not have a dimension). In this case, it's fine to ignore
282 // the object for the purposes of construction.
283 assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
284 if ( ctor.size() == 1 ) {
285 // need to remember init expression, in case no ctors exist
286 // if ctor does exist, want to use ctor expression instead of init
287 // push this decision to the resolver
288 assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
289 return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
290 }
291 return nullptr;
292 }
293
294 DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
295 handleDWT( objDecl );
296 // hands off if @=, extern, builtin, etc.
297 // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
298 if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
299 // constructed objects cannot be designated
300 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 );
301 // constructed objects should not have initializers nested too deeply
302 if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
303
304 objDecl->set_init( genCtorInit( objDecl ) );
305 }
306 return Parent::mutate( objDecl );
307 }
308
309 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
310 ValueGuard< bool > oldInFunc = inFunction;
311 inFunction = true;
312
313 handleDWT( functionDecl );
314
315 managedTypes.beginScope();
316 // go through assertions and recursively add seen ctor/dtors
317 for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
318 for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
319 handleDWT( assertion );
320 }
321 }
322 // parameters should not be constructed and destructed, so don't mutate FunctionType
323 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
324
325 managedTypes.endScope();
326 return functionDecl;
327 }
328
329 Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) {
330 // don't construct members, but need to take note if there is a managed member,
331 // because that means that this type is also managed
332 for ( Declaration * member : aggregateDecl->get_members() ) {
333 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
334 if ( isManaged( field ) ) {
335 StructInstType inst( Type::Qualifiers(), aggregateDecl );
336 managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
337 break;
338 }
339 }
340 }
341 return aggregateDecl;
342 }
343
344 CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
345 managedTypes.beginScope();
346 CompoundStmt * stmt = Parent::mutate( compoundStmt );
347 managedTypes.endScope();
348 return stmt;
349 }
350
351} // namespace InitTweak
352
353// Local Variables: //
354// tab-width: 4 //
355// mode: c++ //
356// compile-command: "make install" //
357// End: //
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