source: src/InitTweak/FixInit.cc@ 3689906

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 3689906 was f1b1e4c, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

can construct global const objects, except with intrinsic constructors
  • Property mode set to 100644
File size: 19.5 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// FixInit.h --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
11// Last Modified By : Rob Schluntz
12// Last Modified On : Fri May 13 11:44:26 2016
13// Update Count : 30
14//
15
16#include <stack>
17#include <list>
18#include "FixInit.h"
19#include "InitTweak.h"
20#include "ResolvExpr/Resolver.h"
21#include "ResolvExpr/typeops.h"
22#include "SynTree/Declaration.h"
23#include "SynTree/Type.h"
24#include "SynTree/Expression.h"
25#include "SynTree/Statement.h"
26#include "SynTree/Initializer.h"
27#include "SynTree/Mutator.h"
28#include "SymTab/Indexer.h"
29#include "GenPoly/PolyMutator.h"
30
31bool ctordtorp = false;
32#define PRINT( text ) if ( ctordtorp ) { text }
33
34namespace InitTweak {
35 namespace {
36 const std::list<Label> noLabels;
37 const std::list<Expression*> noDesignators;
38 }
39
40 class InsertImplicitCalls : public GenPoly::PolyMutator {
41 public:
42 /// wrap function application expressions as ImplicitCopyCtorExpr nodes
43 /// so that it is easy to identify which function calls need their parameters
44 /// to be copy constructed
45 static void insert( std::list< Declaration * > & translationUnit );
46
47 virtual Expression * mutate( ApplicationExpr * appExpr );
48 };
49
50 class ResolveCopyCtors : public SymTab::Indexer {
51 public:
52 /// generate temporary ObjectDecls for each argument and return value of each
53 /// ImplicitCopyCtorExpr, generate/resolve copy construction expressions for each,
54 /// and generate/resolve destructors for both arguments and return value temporaries
55 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
56
57 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
58
59 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
60 ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
61 /// true if type does not need to be copy constructed to ensure correctness
62 bool skipCopyConstruct( Type * );
63 private:
64 TypeSubstitution * env;
65 };
66
67 class FixInit : public GenPoly::PolyMutator {
68 public:
69 /// expand each object declaration to use its constructor after it is declared.
70 /// insert destructor calls at the appropriate places
71 static void fixInitializers( std::list< Declaration * > &translationUnit );
72
73 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
74
75 virtual CompoundStmt * mutate( CompoundStmt * compoundStmt );
76 virtual Statement * mutate( ReturnStmt * returnStmt );
77 virtual Statement * mutate( BranchStmt * branchStmt );
78
79 private:
80 // stack of list of statements - used to differentiate scopes
81 std::list< std::list< Statement * > > dtorStmts;
82 };
83
84 class FixCopyCtors : public GenPoly::PolyMutator {
85 public:
86 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors,
87 /// call expression, and destructors
88 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
89
90 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
91
92 private:
93 // stack of list of statements - used to differentiate scopes
94 std::list< std::list< Statement * > > dtorStmts;
95 };
96
97 void fix( std::list< Declaration * > & translationUnit ) {
98 InsertImplicitCalls::insert( translationUnit );
99 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
100 FixInit::fixInitializers( translationUnit );
101 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
102 FixCopyCtors::fixCopyCtors( translationUnit );
103 }
104
105 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
106 InsertImplicitCalls inserter;
107 mutateAll( translationUnit, inserter );
108 }
109
110 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
111 ResolveCopyCtors resolver;
112 acceptAll( translationUnit, resolver );
113 }
114
115 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
116 FixInit fixer;
117 mutateAll( translationUnit, fixer );
118 }
119
120 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
121 FixCopyCtors fixer;
122 mutateAll( translationUnit, fixer );
123 }
124
125 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
126 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
127 assert( appExpr );
128
129 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
130 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
131 // optimization: don't need to copy construct in order to call intrinsic functions
132 return appExpr;
133 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
134 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
135 assert( ftype );
136 if ( (funcDecl->get_name() == "?{}" || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
137 Type * t1 = ftype->get_parameters().front()->get_type();
138 Type * t2 = ftype->get_parameters().back()->get_type();
139 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
140 assert( ptrType );
141
142 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
143 // optimization: don't need to copy construct in order to call a copy constructor or
144 // assignment operator
145 return appExpr;
146 }
147 } else if ( funcDecl->get_name() == "^?{}" ) {
148 // correctness: never copy construct arguments to a destructor
149 return appExpr;
150 }
151 }
152 }
153 PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
154
155 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
156 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
157 // save the type substitution onto the new node so that it is easy to find.
158 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
159 // The substitution is needed to obtain the type of temporary variables so that copy constructor
160 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
161 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
162 // saves the environment, or compute the types of temporaries here, but it's much simpler to
163 // save the environment here, and more cohesive to compute temporary variables and resolve copy
164 // constructor calls together.
165 assert( env );
166 expr->set_env( env );
167 return expr;
168 }
169
170 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
171 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
172 }
173
174 ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
175 assert( var );
176 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
177 untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
178 if (cpArg) untyped->get_args().push_back( cpArg );
179
180 // resolve copy constructor
181 // should only be one alternative for copy ctor and dtor expressions, since
182 // all arguments are fixed (VariableExpr and already resolved expression)
183 PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
184 ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
185 if ( resolved->get_env() ) {
186 env->add( *resolved->get_env() );
187 }
188
189 assert( resolved );
190 delete untyped;
191 return resolved;
192 }
193
194 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
195 static UniqueName tempNamer("_tmp_cp");
196 static UniqueName retNamer("_tmp_cp_ret");
197
198 PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
199 Visitor::visit( impCpCtorExpr );
200 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
201
202 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
203
204 // take each argument and attempt to copy construct it.
205 for ( Expression * & arg : appExpr->get_args() ) {
206 PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
207 // xxx - need to handle tuple arguments
208 assert( ! arg->get_results().empty() );
209 Type * result = arg->get_results().front();
210 if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
211 // type may involve type variables, so apply type substitution to get temporary variable's actual type
212 result = result->clone();
213 impCpCtorExpr->get_env()->apply( result );
214 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
215 tmp->get_type()->set_isConst( false );
216
217 // create and resolve copy constructor
218 PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
219 ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
220
221 // if the chosen constructor is intrinsic, the copy is unnecessary, so
222 // don't create the temporary and don't call the copy constructor
223 VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
224 assert( function );
225 if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
226 // replace argument to function call with temporary
227 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
228 impCpCtorExpr->get_tempDecls().push_back( tmp );
229 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
230 }
231 }
232
233 // each return value from the call needs to be connected with an ObjectDecl
234 // at the call site, which is initialized with the return value and is destructed
235 // later
236 // xxx - handle multiple return values
237 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
238 // xxx - is this right? callExpr may not have the right environment, because it was attached
239 // at a higher level. Trying to pass that environment along.
240 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
241 for ( Type * result : appExpr->get_results() ) {
242 result = result->clone();
243 impCpCtorExpr->get_env()->apply( result );
244 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
245 ret->get_type()->set_isConst( false );
246 impCpCtorExpr->get_returnDecls().push_back( ret );
247 PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
248 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
249 }
250 PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
251 }
252
253
254 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
255 PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
256
257 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
258 assert( impCpCtorExpr );
259
260 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
261 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
262 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
263
264 // add all temporary declarations and their constructors
265 for ( ObjectDecl * obj : tempDecls ) {
266 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
267 }
268 for ( ObjectDecl * obj : returnDecls ) {
269 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
270 }
271
272 // add destructors after current statement
273 for ( Expression * dtor : dtors ) {
274 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
275 }
276
277 // xxx - update to work with multiple return values
278 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
279 Expression * callExpr = impCpCtorExpr->get_callExpr();
280
281 PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
282
283 // xxx - some of these aren't necessary, and can be removed once this is stable
284 dtors.clear();
285 tempDecls.clear();
286 returnDecls.clear();
287 impCpCtorExpr->set_callExpr( NULL );
288 impCpCtorExpr->set_env( NULL );
289 delete impCpCtorExpr;
290
291 if ( returnDecl ) {
292 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
293 assign->get_args().push_back( new VariableExpr( returnDecl ) );
294 assign->get_args().push_back( callExpr );
295 // know the result type of the assignment is the type of the LHS (minus the pointer), so
296 // add that onto the assignment expression so that later steps have the necessary information
297 assign->add_result( returnDecl->get_type()->clone() );
298
299 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
300 if ( callExpr->get_results().front()->get_isLvalue() ) {
301 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any
302 // lvalue returning non-intrinsic function. Add an AddressExpr to the call to negate
303 // the derefence and change the type of the return temporary from T to T* to properly
304 // capture the return value. Then dereference the result of the comma expression, since
305 // the lvalue returning call was originally wrapped with an AddressExpr.
306 // Effectively, this turns
307 // lvalue T f();
308 // &*f()
309 // into
310 // T * tmp_cp_retN;
311 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
312 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
313 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
314
315 Type * resultType = returnDecl->get_type()->clone();
316 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
317 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
318 deref->get_args().push_back( retExpr );
319 deref->add_result( resultType );
320 retExpr = deref;
321 }
322 // xxx - might need to set env on retExpr...
323 // retExpr->set_env( env->clone() );
324 return retExpr;
325 } else {
326 return callExpr;
327 }
328 }
329
330 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
331 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors
332 // when the init is removed from the ObjectDecl
333 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
334
335 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
336 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
337 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
338 if ( Statement * ctor = ctorInit->get_ctor() ) {
339 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
340 // generate:
341 // static bool __objName_uninitialized = true;
342 // if (__objName_uninitialized) {
343 // __ctor(__objName);
344 // void dtor_atexit() {
345 // __dtor(__objName);
346 // }
347 // on_exit(dtorOnExit, &__objName);
348 // __objName_uninitialized = false;
349 // }
350
351 // generate first line
352 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
353 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
354 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
355 isUninitializedVar->fixUniqueId();
356
357 // void dtor_atexit(...) {...}
358 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + "_dtor_atexit", DeclarationNode::NoStorageClass, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
359 dtorCaller->fixUniqueId();
360 dtorCaller->get_statements()->get_kids().push_back( ctorInit->get_dtor() );
361
362 // on_exit(dtor_atexit);
363 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
364 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
365
366 // __objName_uninitialized = false;
367 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
368 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
369 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
370
371 // generate body of if
372 CompoundStmt * initStmts = new CompoundStmt( noLabels );
373 std::list< Statement * > & body = initStmts->get_kids();
374 body.push_back( ctor );
375 body.push_back( new DeclStmt( noLabels, dtorCaller ) );
376 body.push_back( new ExprStmt( noLabels, callAtexit ) );
377 body.push_back( new ExprStmt( noLabels, setTrue ) );
378
379 // put it all together
380 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
381 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
382 stmtsToAddAfter.push_back( ifStmt );
383 } else {
384 stmtsToAddAfter.push_back( ctor );
385 dtorStmts.back().push_front( ctorInit->get_dtor() );
386 }
387 objDecl->set_init( NULL );
388 ctorInit->set_ctor( NULL );
389 ctorInit->set_dtor( NULL ); // xxx - only destruct when constructing? Probably not?
390 } else if ( Initializer * init = ctorInit->get_init() ) {
391 objDecl->set_init( init );
392 ctorInit->set_init( NULL );
393 } else {
394 // no constructor and no initializer, which is okay
395 objDecl->set_init( NULL );
396 }
397 delete ctorInit;
398 }
399 return objDecl;
400 }
401
402 namespace {
403 template<typename Iterator, typename OutputIterator>
404 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
405 for ( Iterator it = begin ; it != end ; ++it ) {
406 // remove if instrinsic destructor statement. Note that this is only called
407 // on lists of implicit dtors, so if the user manually calls an intrinsic
408 // dtor then the call must (and will) still be generated since the argument
409 // may contain side effects.
410 if ( ! isInstrinsicSingleArgCallStmt( *it ) ) {
411 // don't need to call intrinsic dtor, because it does nothing, but
412 // non-intrinsic dtors must be called
413 *out++ = (*it)->clone();
414 }
415 }
416 }
417 }
418
419 CompoundStmt * FixInit::mutate( CompoundStmt * compoundStmt ) {
420 // mutate statements - this will also populate dtorStmts list.
421 // don't want to dump all destructors when block is left,
422 // just the destructors associated with variables defined in this block,
423 // so push a new list to the top of the stack so that we can differentiate scopes
424 dtorStmts.push_back( std::list<Statement *>() );
425
426 compoundStmt = PolyMutator::mutate( compoundStmt );
427 std::list< Statement * > & statements = compoundStmt->get_kids();
428
429 insertDtors( dtorStmts.back().begin(), dtorStmts.back().end(), back_inserter( statements ) );
430
431 deleteAll( dtorStmts.back() );
432 dtorStmts.pop_back();
433 return compoundStmt;
434 }
435
436 Statement * FixInit::mutate( ReturnStmt * returnStmt ) {
437 for ( std::list< std::list< Statement * > >::reverse_iterator list = dtorStmts.rbegin(); list != dtorStmts.rend(); ++list ) {
438 insertDtors( list->begin(), list->end(), back_inserter( stmtsToAdd ) );
439 }
440 return Mutator::mutate( returnStmt );
441 }
442
443 Statement * FixInit::mutate( BranchStmt * branchStmt ) {
444 // TODO: adding to the end of a block isn't sufficient, since
445 // return/break/goto should trigger destructor when block is left.
446 switch( branchStmt->get_type() ) {
447 case BranchStmt::Continue:
448 case BranchStmt::Break:
449 insertDtors( dtorStmts.back().begin(), dtorStmts.back().end(), back_inserter( stmtsToAdd ) );
450 break;
451 case BranchStmt::Goto:
452 // xxx
453 // if goto leaves a block, generate dtors for every block it leaves
454 // if goto is in same block but earlier statement, destruct every object that was defined after the statement
455 break;
456 default:
457 assert( false );
458 }
459 return Mutator::mutate( branchStmt );
460 }
461
462
463} // namespace InitTweak
464
465// Local Variables: //
466// tab-width: 4 //
467// mode: c++ //
468// compile-command: "make install" //
469// End: //
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