source: src/InitTweak/RemoveInit.cc@ 5b40f30

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors ctor deferred_resn demangler enum forall-pointer-decay gc_noraii jacob/cs343-translation jenkins-sandbox memory 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 5b40f30 was 5b40f30, checked in by Rob Schluntz <rschlunt@…>, 10 years ago

generate correct empty list initializer, ensure function return value is not incorrectly destructed before it is returned, do not add src parameter to autogenerated routines when they take a single argument
  • Property mode set to 100644
File size: 10.6 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// RemoveInit.cc --
8//
9// Author : Rob Schluntz
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Rob Schluntz
12// Last Modified On : Tue Feb 09 15:12:29 2016
13// Update Count : 166
14//
15
16#include <stack>
17#include <list>
18#include "RemoveInit.h"
19#include "SynTree/Declaration.h"
20#include "SynTree/Type.h"
21#include "SynTree/Expression.h"
22#include "SynTree/Statement.h"
23#include "SynTree/Initializer.h"
24#include "SynTree/Mutator.h"
25#include "SymTab/Autogen.h"
26#include "GenPoly/PolyMutator.h"
27
28namespace InitTweak {
29 namespace {
30 const std::list<Label> noLabels;
31 const std::list<Expression *> noDesignators;
32 }
33
34 class RemoveInit : public GenPoly::PolyMutator {
35 public:
36 /// removes and replaces initialization for polymorphic value objects
37 /// with assignment (TODO: constructor) statements.
38 /// also consistently allocates a temporary variable for the return value
39 /// of a function so that anything which the resolver decides can be assigned
40 /// into the return type of a function can be returned.
41 static void removeInitializers( std::list< Declaration * > &translationUnit );
42
43 RemoveInit();
44 virtual ObjectDecl * mutate( ObjectDecl *objDecl );
45 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );
46
47 virtual Statement * mutate( ReturnStmt * returnStmt );
48
49 protected:
50 std::list<DeclarationWithType*> returnVals;
51 UniqueName tempNamer;
52 std::string funcName;
53 };
54
55 class CtorDtor : public GenPoly::PolyMutator {
56 public:
57 /// create constructor and destructor statements for object declarations.
58 /// Destructors are inserted directly into the code, whereas constructors
59 /// will be added in after the resolver has run so that the initializer expression
60 /// is only removed if a constructor is found
61 static void generateCtorDtor( std::list< Declaration * > &translationUnit );
62
63 CtorDtor() : inFunction( false ) {}
64
65 virtual ObjectDecl * mutate( ObjectDecl * );
66 virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );
67 virtual Declaration* mutate( StructDecl *aggregateDecl );
68 virtual Declaration* mutate( UnionDecl *aggregateDecl );
69 virtual Declaration* mutate( EnumDecl *aggregateDecl );
70 virtual Declaration* mutate( ContextDecl *aggregateDecl );
71 virtual TypeDecl* mutate( TypeDecl *typeDecl );
72 virtual Declaration* mutate( TypedefDecl *typeDecl );
73
74 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt );
75
76 protected:
77 bool inFunction;
78
79 // to be added before block ends - use push_front so order is correct
80 std::list< Statement * > destructorStmts;
81 };
82
83 void tweak( std::list< Declaration * > & translationUnit ) {
84 RemoveInit::removeInitializers( translationUnit );
85 CtorDtor::generateCtorDtor( translationUnit );
86 }
87
88 void RemoveInit::removeInitializers( std::list< Declaration * > & translationUnit ) {
89 RemoveInit remover;
90 mutateAll( translationUnit, remover );
91 }
92
93 RemoveInit::RemoveInit() : tempNamer( "_retVal" ) {}
94
95 // in the case where an object has an initializer and a polymorphic type, insert an assignment immediately after the
96 // declaration. This will (seemingly) cause the later phases to do the right thing with the assignment
97 ObjectDecl *RemoveInit::mutate( ObjectDecl *objDecl ) {
98 if (objDecl->get_init() && dynamic_cast<TypeInstType*>(objDecl->get_type())) {
99 if (SingleInit * single = dynamic_cast<SingleInit*>(objDecl->get_init())) {
100 // xxx this can be more complicated - consider ListInit
101 UntypedExpr *assign = new UntypedExpr( new NameExpr( "?{}" ) );
102 assign->get_args().push_back( new AddressExpr (new NameExpr( objDecl->get_name() ) ) );
103 assign->get_args().push_back( single->get_value()->clone() );
104 stmtsToAddAfter.push_back(new ExprStmt(noLabels, assign));
105 } // if
106 } // if
107 return objDecl;
108 }
109
110 Statement *RemoveInit::mutate( ReturnStmt *returnStmt ) {
111 // update for multiple return values
112 assert( returnVals.size() == 0 || returnVals.size() == 1 );
113 // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
114 // is being returned
115 if ( returnStmt->get_expr() && returnVals.size() == 1 && funcName != "?=?" && ! returnVals.front()->get_type()->get_isLvalue() ) {
116 // ensure return value is not destructed by explicitly creating
117 // an empty SingleInit node wherein maybeConstruct is false
118 ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, returnVals.front()->get_type()->clone(), new ListInit( std::list<Initializer*>(), noDesignators, false ) );
119 stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) );
120
121 // and explicitly create the constructor expression separately
122 UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
123 construct->get_args().push_back( new AddressExpr (new NameExpr( newObj->get_name() ) ) );
124 construct->get_args().push_back( returnStmt->get_expr() );
125 stmtsToAdd.push_back(new ExprStmt(noLabels, construct));
126
127 returnStmt->set_expr( new VariableExpr( newObj ) );
128 } // if
129 return returnStmt;
130 }
131
132 DeclarationWithType* RemoveInit::mutate( FunctionDecl *functionDecl ) {
133 std::list<DeclarationWithType*> oldReturnVals = returnVals;
134 std::string oldFuncName = funcName;
135
136 FunctionType * type = functionDecl->get_functionType();
137 returnVals = type->get_returnVals();
138 funcName = functionDecl->get_name();
139 DeclarationWithType * decl = Mutator::mutate( functionDecl );
140 returnVals = oldReturnVals;
141 funcName = oldFuncName;
142 return decl;
143 }
144
145
146 void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
147 CtorDtor ctordtor;
148 mutateAll( translationUnit, ctordtor );
149 }
150
151 namespace {
152 bool tryConstruct( ObjectDecl * objDecl ) {
153 // xxx - handle designations
154 return ! LinkageSpec::isBuiltin( objDecl->get_linkage() ) &&
155 (objDecl->get_init() == NULL ||
156 ( objDecl->get_init() != NULL && objDecl->get_init()->get_maybeConstructed() ));
157 }
158
159 Expression * makeCtorDtorExpr( std::string name, ObjectDecl * objDecl, std::list< Expression * > args ) {
160 UntypedExpr * expr = new UntypedExpr( new NameExpr( name ) );
161 expr->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) );
162 expr->get_args().splice( expr->get_args().end(), args );
163 return expr;
164 }
165
166 class InitExpander : public Visitor {
167 public:
168 InitExpander() {}
169 // ~InitExpander() {}
170 virtual void visit( SingleInit * singleInit );
171 virtual void visit( ListInit * listInit );
172 std::list< Expression * > argList;
173 };
174
175 void InitExpander::visit( SingleInit * singleInit ) {
176 argList.push_back( singleInit->get_value()->clone() );
177 }
178
179 void InitExpander::visit( ListInit * listInit ) {
180 // xxx - for now, assume no nested list inits
181 std::list<Initializer*>::iterator it = listInit->begin_initializers();
182 for ( ; it != listInit->end_initializers(); ++it ) {
183 (*it)->accept( *this );
184 }
185 }
186
187 std::list< Expression * > makeInitList( Initializer * init ) {
188 InitExpander expander;
189 maybeAccept( init, expander );
190 return expander.argList;
191 }
192 }
193
194 ObjectDecl * CtorDtor::mutate( ObjectDecl * objDecl ) {
195 // hands off if designated or if @=
196 if ( tryConstruct( objDecl ) ) {
197 if ( inFunction ) {
198 if ( ArrayType * at = dynamic_cast< ArrayType * >( objDecl->get_type() ) ) {
199 // call into makeArrayFunction from validate.cc to generate calls to ctor/dtor for each element of array
200 // TODO: walk initializer and generate appropriate copy ctor if element has initializer
201 SymTab::makeArrayFunction( NULL, new VariableExpr( objDecl ), at, "?{}", back_inserter( stmtsToAddAfter ) );
202 SymTab::makeArrayFunction( NULL, new VariableExpr( objDecl ), at, "^?{}", front_inserter( destructorStmts ), false );
203 } else {
204 // it's sufficient to attempt to call the ctor/dtor for the given object and its initializer
205 Expression * ctor = makeCtorDtorExpr( "?{}", objDecl, makeInitList( objDecl->get_init() ) );
206 Expression * dtor = makeCtorDtorExpr( "^?{}", objDecl, std::list< Expression * >() );
207
208 // need to remember init expression, in case no ctors exist
209 // if ctor does exist, want to use ctor expression instead of init
210 // push this decision to the resolver
211 objDecl->set_init( new ConstructorInit( ctor, objDecl->get_init() ) );
212 destructorStmts.push_front( new ExprStmt( noLabels, dtor ) );
213 }
214 } else {
215 // xxx - find a way to construct/destruct globals
216 // hack: implicit "static" initialization routine for each struct type? or something similar?
217 // --ties into module system
218 // this can be done by mangling main and replacing it with our own main which calls each
219 // module initialization routine in some decided order (order given in link command?)
220 // and finally calls mangled main
221 }
222 }
223 return objDecl;
224 }
225
226 DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
227 // parameters should not be constructed and destructed, so don't mutate FunctionType
228 bool oldInFunc = inFunction;
229 mutateAll( functionDecl->get_oldDecls(), *this );
230 inFunction = true;
231 functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
232 inFunction = oldInFunc;
233 return functionDecl;
234 }
235
236 CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
237 // don't want to dump all destructors when block is left,
238 // just the destructors associated with variables defined in this block
239 std::list< Statement * > oldDestructorStmts = destructorStmts;
240 destructorStmts = std::list<Statement *>();
241
242 CompoundStmt * ret = PolyMutator::mutate( compoundStmt );
243 std::list< Statement * > &statements = ret->get_kids();
244 if ( ! destructorStmts.empty() ) {
245 // TODO: adding to the end of a block isn't sufficient, since
246 // return/break/goto should trigger destructor when block is left.
247 statements.splice( statements.end(), destructorStmts );
248 } // if
249
250 destructorStmts = oldDestructorStmts;
251 return ret;
252 }
253
254 // should not traverse into any of these declarations to find objects
255 // that need to be constructed or destructed
256 Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) { return aggregateDecl; }
257 Declaration* CtorDtor::mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; }
258 Declaration* CtorDtor::mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; }
259 Declaration* CtorDtor::mutate( ContextDecl *aggregateDecl ) { return aggregateDecl; }
260 TypeDecl* CtorDtor::mutate( TypeDecl *typeDecl ) { return typeDecl; }
261 Declaration* CtorDtor::mutate( TypedefDecl *typeDecl ) { return typeDecl; }
262
263} // namespace InitTweak
264
265// Local Variables: //
266// tab-width: 4 //
267// mode: c++ //
268// compile-command: "make install" //
269// End: //
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