source: src/InitTweak/FixInit.cc@ f20dffa

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 f20dffa was 597db97f, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

fix order of destruction of unique expressions
  • Property mode set to 100644
File size: 52.0 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// FixInit.h --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Fri Mar 17 09:13:47 2017
13// Update Count : 71
14//
15
16#include <stack>
17#include <list>
18#include <iterator>
19#include <algorithm>
20#include <unordered_map>
21#include <unordered_set>
22#include "InitTweak.h"
23#include "GenInit.h"
24#include "FixInit.h"
25#include "FixGlobalInit.h"
26#include "ResolvExpr/Resolver.h"
27#include "ResolvExpr/typeops.h"
28#include "SynTree/Declaration.h"
29#include "SynTree/Type.h"
30#include "SynTree/Expression.h"
31#include "SynTree/Attribute.h"
32#include "SynTree/Statement.h"
33#include "SynTree/Initializer.h"
34#include "SynTree/Mutator.h"
35#include "SymTab/Indexer.h"
36#include "SymTab/Autogen.h"
37#include "GenPoly/PolyMutator.h"
38#include "GenPoly/DeclMutator.h"
39#include "SynTree/AddStmtVisitor.h"
40#include "CodeGen/GenType.h" // for warning/error messages
41#include "Tuples/Tuples.h"
42
43bool ctordtorp = false; // print all debug
44bool ctorp = false; // print ctor debug
45bool cpctorp = false; // print copy ctor debug
46bool dtorp = false; // print dtor debug
47#define PRINT( text ) if ( ctordtorp ) { text }
48#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
49#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
50
51namespace InitTweak {
52 namespace {
53 typedef std::unordered_map< Expression *, TypeSubstitution * > EnvMap;
54 typedef std::unordered_map< int, int > UnqCount;
55
56 class InsertImplicitCalls final : public GenPoly::PolyMutator {
57 public:
58 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
59 /// function calls need their parameters to be copy constructed
60 static void insert( std::list< Declaration * > & translationUnit, EnvMap & envMap );
61
62 InsertImplicitCalls( EnvMap & envMap ) : envMap( envMap ) {}
63 typedef GenPoly::PolyMutator Parent;
64 using Parent::mutate;
65 virtual Expression * mutate( ApplicationExpr * appExpr ) override;
66 virtual Expression * mutate( StmtExpr * stmtExpr ) override;
67
68 // collects environments for relevant nodes
69 EnvMap & envMap;
70 };
71
72 class ResolveCopyCtors final : public SymTab::Indexer {
73 public:
74 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
75 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
76 /// arguments and return value temporaries
77 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit, const EnvMap & envMap, UnqCount & unqCount );
78
79 typedef SymTab::Indexer Parent;
80 using Parent::visit;
81
82 ResolveCopyCtors( const EnvMap & envMap, UnqCount & unqCount ) : envMap( envMap ), unqCount( unqCount ) {}
83
84 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr ) override;
85 virtual void visit( UniqueExpr * unqExpr ) override;
86 virtual void visit( StmtExpr * stmtExpr ) override;
87
88 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
89 Expression * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
90 /// true if type does not need to be copy constructed to ensure correctness
91 bool skipCopyConstruct( Type * type );
92 void copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr );
93 void destructRet( ObjectDecl * ret, ImplicitCopyCtorExpr * impCpCtorExpr );
94
95 TypeSubstitution * env;
96 const EnvMap & envMap;
97 UnqCount & unqCount; // count the number of times each unique expr ID appears
98 };
99
100 /// collects constructed object decls - used as a base class
101 class ObjDeclCollector : public AddStmtVisitor {
102 public:
103 typedef AddStmtVisitor Parent;
104 using Parent::visit;
105 typedef std::set< ObjectDecl * > ObjectSet;
106 virtual void visit( CompoundStmt *compoundStmt ) override;
107 virtual void visit( DeclStmt *stmt ) override;
108
109 // don't go into other functions
110 virtual void visit( FunctionDecl *decl ) override {}
111
112 protected:
113 ObjectSet curVars;
114 };
115
116 // debug
117 struct printSet {
118 typedef ObjDeclCollector::ObjectSet ObjectSet;
119 printSet( const ObjectSet & objs ) : objs( objs ) {}
120 const ObjectSet & objs;
121 };
122 std::ostream & operator<<( std::ostream & out, const printSet & set) {
123 out << "{ ";
124 for ( ObjectDecl * obj : set.objs ) {
125 out << obj->get_name() << ", " ;
126 } // for
127 out << " }";
128 return out;
129 }
130
131 class LabelFinder final : public ObjDeclCollector {
132 public:
133 typedef ObjDeclCollector Parent;
134 typedef std::map< Label, ObjectSet > LabelMap;
135 // map of Label -> live variables at that label
136 LabelMap vars;
137
138 void handleStmt( Statement * stmt );
139
140 // xxx - This needs to be done better.
141 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
142 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
143 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
144 // every specialized class knows about every new kind of statement that might be added.
145 using Parent::visit;
146 virtual void visit( CompoundStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
147 virtual void visit( ExprStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
148 virtual void visit( AsmStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
149 virtual void visit( IfStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
150 virtual void visit( WhileStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
151 virtual void visit( ForStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
152 virtual void visit( SwitchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
153 virtual void visit( CaseStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
154 virtual void visit( BranchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
155 virtual void visit( ReturnStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
156 virtual void visit( TryStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
157 virtual void visit( CatchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
158 virtual void visit( FinallyStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
159 virtual void visit( NullStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
160 virtual void visit( DeclStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
161 virtual void visit( ImplicitCtorDtorStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
162 };
163
164 class InsertDtors final : public ObjDeclCollector {
165 public:
166 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
167 /// (currently by FixInit)
168 static void insert( std::list< Declaration * > & translationUnit );
169
170 typedef ObjDeclCollector Parent;
171 typedef std::list< ObjectDecl * > OrderedDecls;
172 typedef std::list< OrderedDecls > OrderedDeclsStack;
173
174 InsertDtors( LabelFinder & finder ) : finder( finder ), labelVars( finder.vars ) {}
175
176 using Parent::visit;
177
178 virtual void visit( ObjectDecl * objDecl ) override;
179 virtual void visit( FunctionDecl * funcDecl ) override;
180
181 virtual void visit( CompoundStmt * compoundStmt ) override;
182 virtual void visit( ReturnStmt * returnStmt ) override;
183 virtual void visit( BranchStmt * stmt ) override;
184 private:
185 void handleGoto( BranchStmt * stmt );
186
187 LabelFinder & finder;
188 LabelFinder::LabelMap & labelVars;
189 OrderedDeclsStack reverseDeclOrder;
190 };
191
192 class FixInit final : public GenPoly::PolyMutator {
193 public:
194 /// expand each object declaration to use its constructor after it is declared.
195 static void fixInitializers( std::list< Declaration * > &translationUnit );
196
197 typedef GenPoly::PolyMutator Parent;
198 using Parent::mutate;
199 virtual DeclarationWithType * mutate( ObjectDecl *objDecl ) override;
200
201 std::list< Declaration * > staticDtorDecls;
202 };
203
204 class FixCopyCtors final : public GenPoly::PolyMutator {
205 public:
206 FixCopyCtors( UnqCount & unqCount ) : unqCount( unqCount ){}
207 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
208 /// and destructors
209 static void fixCopyCtors( std::list< Declaration * > &translationUnit, UnqCount & unqCount );
210
211 typedef GenPoly::PolyMutator Parent;
212 using Parent::mutate;
213 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) override;
214 virtual Expression * mutate( UniqueExpr * unqExpr ) override;
215 virtual Expression * mutate( StmtExpr * stmtExpr ) override;
216
217 UnqCount & unqCount;
218 };
219
220 class GenStructMemberCalls final : public SymTab::Indexer {
221 public:
222 typedef Indexer Parent;
223 /// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
224 /// for any member that is missing a corresponding ctor/dtor call.
225 /// error if a member is used before constructed
226 static void generate( std::list< Declaration * > & translationUnit );
227
228 using Parent::visit;
229
230 virtual void visit( FunctionDecl * funcDecl ) override;
231
232 virtual void visit( MemberExpr * memberExpr ) override;
233 virtual void visit( ApplicationExpr * appExpr ) override;
234
235 SemanticError errors;
236 private:
237 void handleFirstParam( Expression * firstParam );
238 template< typename... Params >
239 void emit( CodeLocation, const Params &... params );
240
241 FunctionDecl * function = 0;
242 std::set< DeclarationWithType * > unhandled;
243 std::map< DeclarationWithType *, CodeLocation > usedUninit;
244 ObjectDecl * thisParam = 0;
245 bool isCtor = false; // true if current function is a constructor
246 StructDecl * structDecl = 0;
247 };
248
249 // very simple resolver-like mutator class - used to
250 // resolve UntypedExprs that are found within newly
251 // generated constructor/destructor calls
252 class MutatingResolver final : public Mutator {
253 public:
254 MutatingResolver( SymTab::Indexer & indexer ) : indexer( indexer ) {}
255
256 using Mutator::mutate;
257 virtual DeclarationWithType* mutate( ObjectDecl *objectDecl ) override;
258 virtual Expression* mutate( UntypedExpr *untypedExpr ) override;
259
260 private:
261 SymTab::Indexer & indexer;
262 };
263
264 class FixCtorExprs final : public GenPoly::DeclMutator {
265 public:
266 /// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
267 static void fix( std::list< Declaration * > & translationUnit );
268
269 using GenPoly::DeclMutator::mutate;
270 virtual Expression * mutate( ConstructorExpr * ctorExpr ) override;
271 };
272 } // namespace
273
274 void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
275 // fixes ConstructorInit for global variables. should happen before fixInitializers.
276 InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
277
278 EnvMap envMap;
279 UnqCount unqCount;
280
281 InsertImplicitCalls::insert( translationUnit, envMap );
282 ResolveCopyCtors::resolveImplicitCalls( translationUnit, envMap, unqCount );
283 InsertDtors::insert( translationUnit );
284 FixInit::fixInitializers( translationUnit );
285
286 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
287 FixCopyCtors::fixCopyCtors( translationUnit, unqCount );
288
289 GenStructMemberCalls::generate( translationUnit );
290 // xxx - ctor expansion currently has to be after FixCopyCtors, because there is currently a
291 // hack in the way untyped assignments are generated, where the first argument cannot have
292 // its address taken because of the way codegeneration handles UntypedExpr vs. ApplicationExpr.
293 // Thus such assignment exprs must never pushed through expression resolution (and thus should
294 // not go through the FixCopyCtors pass), otherwise they will fail -- guaranteed.
295 // Also needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
296 // don't look right, and a member can be constructed more than once.
297 FixCtorExprs::fix( translationUnit );
298 }
299
300 namespace {
301 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit, EnvMap & envMap ) {
302 InsertImplicitCalls inserter( envMap );
303 mutateAll( translationUnit, inserter );
304 }
305
306 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit, const EnvMap & envMap, UnqCount & unqCount ) {
307 ResolveCopyCtors resolver( envMap, unqCount );
308 acceptAll( translationUnit, resolver );
309 }
310
311 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
312 FixInit fixer;
313
314 // can't use mutateAll, because need to insert declarations at top-level
315 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
316 SemanticError errors;
317 for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
318 try {
319 *i = maybeMutate( *i, fixer );
320 translationUnit.splice( i, fixer.staticDtorDecls );
321 } catch( SemanticError &e ) {
322 e.set_location( (*i)->location );
323 errors.append( e );
324 } // try
325 } // for
326 if ( ! errors.isEmpty() ) {
327 throw errors;
328 } // if
329 }
330
331 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
332 LabelFinder finder;
333 InsertDtors inserter( finder );
334 acceptAll( translationUnit, inserter );
335 }
336
337 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit, UnqCount & unqCount ) {
338 FixCopyCtors fixer( unqCount );
339 mutateAll( translationUnit, fixer );
340 }
341
342 void GenStructMemberCalls::generate( std::list< Declaration * > & translationUnit ) {
343 GenStructMemberCalls warner;
344 acceptAll( translationUnit, warner );
345 }
346
347 void FixCtorExprs::fix( std::list< Declaration * > & translationUnit ) {
348 FixCtorExprs fixer;
349 fixer.mutateDeclarationList( translationUnit );
350 }
351
352 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
353 appExpr = dynamic_cast< ApplicationExpr * >( Parent::mutate( appExpr ) );
354 assert( appExpr );
355
356 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
357 if ( LinkageSpec::isBuiltin( function->get_var()->get_linkage() ) ) {
358 // optimization: don't need to copy construct in order to call intrinsic functions
359 return appExpr;
360 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
361 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
362 assert( ftype );
363 if ( (isConstructor( funcDecl->get_name() ) || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
364 Type * t1 = ftype->get_parameters().front()->get_type();
365 Type * t2 = ftype->get_parameters().back()->get_type();
366 PointerType * ptrType = safe_dynamic_cast< PointerType * > ( t1 );
367
368 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
369 // optimization: don't need to copy construct in order to call a copy constructor or
370 // assignment operator
371 return appExpr;
372 } // if
373 } else if ( isDestructor( funcDecl->get_name() ) ) {
374 // correctness: never copy construct arguments to a destructor
375 return appExpr;
376 } // if
377 } // if
378 } // if
379 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
380
381 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
382 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
383 // save the type substitution into the envMap so that it is easy to find.
384 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
385 // The substitution is needed to obtain the type of temporary variables so that copy constructor
386 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
387 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
388 // saves the environment, or compute the types of temporaries here, but it's much simpler to
389 // save the environment here, and more cohesive to compute temporary variables and resolve copy
390 // constructor calls together.
391 assert( env );
392 envMap[expr] = env;
393 return expr;
394 }
395
396 Expression * InsertImplicitCalls::mutate( StmtExpr * stmtExpr ) {
397 assert( env );
398 envMap[stmtExpr] = env;
399 return Parent::mutate( stmtExpr );
400 }
401
402 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
403 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type ) || Tuples::isTtype( type );
404 }
405
406 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
407 assert( var );
408 // arrays are not copy constructed, so this should always be an ExprStmt
409 ImplicitCtorDtorStmt * stmt = genCtorDtor( fname, var, cpArg );
410 ExprStmt * exprStmt = safe_dynamic_cast< ExprStmt * >( stmt->get_callStmt() );
411 Expression * untyped = exprStmt->get_expr();
412
413 // resolve copy constructor
414 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
415 // (VariableExpr and already resolved expression)
416 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
417 Expression * resolved = ResolvExpr::findVoidExpression( untyped, *this );
418 assert( resolved );
419 if ( resolved->get_env() ) {
420 // Extract useful information and discard new environments. Keeping them causes problems in PolyMutator passes.
421 env->add( *resolved->get_env() );
422 delete resolved->get_env();
423 resolved->set_env( nullptr );
424 } // if
425
426 delete stmt;
427 return resolved;
428 }
429
430 void ResolveCopyCtors::copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr ) {
431 static UniqueName tempNamer("_tmp_cp");
432 assert( env );
433 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *env << std::endl; )
434 assert( arg->has_result() );
435 Type * result = arg->get_result();
436 if ( skipCopyConstruct( result ) ) return; // skip certain non-copyable types
437
438 // type may involve type variables, so apply type substitution to get temporary variable's actual type
439 result = result->clone();
440 env->apply( result );
441 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
442 tmp->get_type()->set_const( false );
443
444 // create and resolve copy constructor
445 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
446 Expression * cpCtor = makeCtorDtor( "?{}", tmp, arg );
447
448 if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( cpCtor ) ) {
449 // if the chosen constructor is intrinsic, the copy is unnecessary, so
450 // don't create the temporary and don't call the copy constructor
451 VariableExpr * function = dynamic_cast< VariableExpr * >( appExpr->get_function() );
452 assert( function );
453 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) return;
454 }
455
456 // replace argument to function call with temporary
457 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
458 impCpCtorExpr->get_tempDecls().push_back( tmp );
459 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
460 }
461
462 void ResolveCopyCtors::destructRet( ObjectDecl * ret, ImplicitCopyCtorExpr * impCpCtorExpr ) {
463 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
464 }
465
466 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
467 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
468 Parent::visit( impCpCtorExpr );
469 env = envMap.at(impCpCtorExpr);
470 assert( env );
471
472 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
473
474 // take each argument and attempt to copy construct it.
475 for ( Expression * & arg : appExpr->get_args() ) {
476 copyConstructArg( arg, impCpCtorExpr );
477 } // for
478
479 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
480 // initialized with the return value and is destructed later
481 // xxx - handle named return values?
482 Type * result = appExpr->get_result();
483 if ( ! result->isVoid() ) {
484 static UniqueName retNamer("_tmp_cp_ret");
485 result = result->clone();
486 env->apply( result );
487 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
488 ret->get_type()->set_const( false );
489 impCpCtorExpr->get_returnDecls().push_back( ret );
490 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
491 if ( ! result->get_lvalue() ) {
492 // destructing lvalue returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary
493 destructRet( ret, impCpCtorExpr );
494 }
495 } // for
496 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
497 }
498
499 void ResolveCopyCtors::visit( StmtExpr * stmtExpr ) {
500 Parent::visit( stmtExpr );
501 env = envMap.at(stmtExpr);
502 assert( stmtExpr->get_result() );
503 Type * result = stmtExpr->get_result();
504 if ( ! result->isVoid() ) {
505 static UniqueName retNamer("_tmp_stmtexpr_ret");
506
507 // create variable that will hold the result of the stmt expr
508 result = result->clone();
509 env->apply( result );
510 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
511 ret->get_type()->set_const( false );
512 stmtExpr->get_returnDecls().push_front( ret );
513
514 // must have a non-empty body, otherwise it wouldn't have a result
515 CompoundStmt * body = stmtExpr->get_statements();
516 assert( ! body->get_kids().empty() );
517 // must be an ExprStmt, otherwise it wouldn't have a result
518 ExprStmt * last = safe_dynamic_cast< ExprStmt * >( body->get_kids().back() );
519 last->set_expr( makeCtorDtor( "?{}", ret, last->get_expr() ) );
520
521 stmtExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
522 } // if
523
524 }
525
526 void ResolveCopyCtors::visit( UniqueExpr * unqExpr ) {
527 static std::unordered_set< int > vars;
528 unqCount[ unqExpr->get_id() ]++; // count the number of unique expressions for each ID
529 if ( vars.count( unqExpr->get_id() ) ) {
530 // xxx - hack to prevent double-handling of unique exprs, otherwise too many temporary variables and destructors are generated
531 return;
532 }
533
534 Parent::visit( unqExpr );
535 // it should never be necessary to wrap a void-returning expression in a UniqueExpr - if this assumption changes, this needs to be rethought
536 assert( unqExpr->get_result() );
537 if ( ImplicitCopyCtorExpr * impCpCtorExpr = dynamic_cast<ImplicitCopyCtorExpr*>( unqExpr->get_expr() ) ) {
538 // note the variable used as the result from the call
539 assert( impCpCtorExpr->get_result() && impCpCtorExpr->get_returnDecls().size() == 1 );
540 unqExpr->set_var( new VariableExpr( impCpCtorExpr->get_returnDecls().front() ) );
541 } else {
542 // expr isn't a call expr, so create a new temporary variable to use to hold the value of the unique expression
543 unqExpr->set_object( new ObjectDecl( toString("_unq", unqExpr->get_id()), Type::StorageClasses(), LinkageSpec::C, nullptr, unqExpr->get_result()->clone(), nullptr ) );
544 unqExpr->set_var( new VariableExpr( unqExpr->get_object() ) );
545 }
546 vars.insert( unqExpr->get_id() );
547 }
548
549 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
550 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
551
552 impCpCtorExpr = safe_dynamic_cast< ImplicitCopyCtorExpr * >( Parent::mutate( impCpCtorExpr ) );
553 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
554 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
555 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
556
557 // add all temporary declarations and their constructors
558 for ( ObjectDecl * obj : tempDecls ) {
559 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
560 } // for
561 for ( ObjectDecl * obj : returnDecls ) {
562 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
563 } // for
564
565 // add destructors after current statement
566 for ( Expression * dtor : dtors ) {
567 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
568 } // for
569
570 // xxx - update to work with multiple return values
571 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
572 Expression * callExpr = impCpCtorExpr->get_callExpr();
573
574 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
575
576 // detach fields from wrapper node so that it can be deleted without deleting too much
577 dtors.clear();
578 tempDecls.clear();
579 returnDecls.clear();
580 impCpCtorExpr->set_callExpr( NULL );
581 impCpCtorExpr->set_env( NULL );
582 delete impCpCtorExpr;
583
584 if ( returnDecl ) {
585 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
586 assign->get_args().push_back( new VariableExpr( returnDecl ) );
587 assign->get_args().push_back( callExpr );
588 // know the result type of the assignment is the type of the LHS (minus the pointer), so
589 // add that onto the assignment expression so that later steps have the necessary information
590 assign->set_result( returnDecl->get_type()->clone() );
591
592 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
593 if ( callExpr->get_result()->get_lvalue() ) {
594 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
595 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
596 // type of the return temporary from T to T* to properly capture the return value. Then dereference
597 // the result of the comma expression, since the lvalue returning call was originally wrapped with
598 // an AddressExpr. Effectively, this turns
599 // lvalue T f();
600 // &*f();
601 // into
602 // T * f();
603 // T * tmp_cp_retN;
604 // &*(tmp_cp_retN = &*f(), tmp_cp_retN); // the first * and second & are generated here
605 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
606 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
607
608 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
609 retExpr->set_result( new PointerType( Type::Qualifiers(), retExpr->get_result() ) );
610 retExpr = UntypedExpr::createDeref( retExpr );
611 } // if
612 // move env from callExpr to retExpr
613 retExpr->set_env( callExpr->get_env() );
614 callExpr->set_env( nullptr );
615 return retExpr;
616 } else {
617 return callExpr;
618 } // if
619 }
620
621 Expression * FixCopyCtors::mutate( StmtExpr * stmtExpr ) {
622 stmtExpr = safe_dynamic_cast< StmtExpr * >( Parent::mutate( stmtExpr ) );
623 assert( stmtExpr->get_result() );
624 Type * result = stmtExpr->get_result();
625 if ( ! result->isVoid() ) {
626 for ( ObjectDecl * obj : stmtExpr->get_returnDecls() ) {
627 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
628 } // for
629 // add destructors after current statement
630 for ( Expression * dtor : stmtExpr->get_dtors() ) {
631 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
632 } // for
633 // must have a non-empty body, otherwise it wouldn't have a result
634 CompoundStmt * body = stmtExpr->get_statements();
635 assert( ! body->get_kids().empty() );
636 assert( ! stmtExpr->get_returnDecls().empty() );
637 body->get_kids().push_back( new ExprStmt( noLabels, new VariableExpr( stmtExpr->get_returnDecls().front() ) ) );
638 }
639 stmtExpr->get_returnDecls().clear();
640 stmtExpr->get_dtors().clear();
641 return stmtExpr;
642 }
643
644 Expression * FixCopyCtors::mutate( UniqueExpr * unqExpr ) {
645 unqCount[ unqExpr->get_id() ]--;
646 static std::unordered_map< int, std::list< Statement * > > dtors;
647 static std::unordered_map< int, UniqueExpr * > unqMap;
648 static std::unordered_set< int > addDeref;
649 // has to be done to clean up ImplicitCopyCtorExpr nodes, even when this node was skipped in previous passes
650 if ( unqMap.count( unqExpr->get_id() ) ) {
651 // take data from other UniqueExpr to ensure consistency
652 delete unqExpr->get_expr();
653 unqExpr->set_expr( unqMap[unqExpr->get_id()]->get_expr()->clone() );
654 delete unqExpr->get_result();
655 unqExpr->set_result( maybeClone( unqExpr->get_expr()->get_result() ) );
656 if ( unqCount[ unqExpr->get_id() ] == 0 ) { // insert destructor after the last use of the unique expression
657 stmtsToAdd.splice( stmtsToAddAfter.end(), dtors[ unqExpr->get_id() ] );
658 }
659 if ( addDeref.count( unqExpr->get_id() ) ) {
660 // other UniqueExpr was dereferenced because it was an lvalue return, so this one should be too
661 return UntypedExpr::createDeref( unqExpr );
662 }
663 return unqExpr;
664 }
665 FixCopyCtors fixer( unqCount );
666 unqExpr->set_expr( unqExpr->get_expr()->acceptMutator( fixer ) ); // stmtexprs contained should not be separately fixed, so this must occur after the lookup
667 stmtsToAdd.splice( stmtsToAdd.end(), fixer.stmtsToAdd );
668 unqMap[unqExpr->get_id()] = unqExpr;
669 if ( UntypedExpr * deref = dynamic_cast< UntypedExpr * >( unqExpr->get_expr() ) ) {
670 // unique expression is now a dereference, because the inner expression is an lvalue returning function call.
671 // Normalize the expression by dereferencing the unique expression, rather than the inner expression
672 // (i.e. move the dereference out a level)
673 assert( getFunctionName( deref ) == "*?" );
674 unqExpr->set_expr( getCallArg( deref, 0 ) );
675 getCallArg( deref, 0 ) = unqExpr;
676 addDeref.insert( unqExpr->get_id() );
677 if ( unqCount[ unqExpr->get_id() ] == 0 ) { // insert destructor after the last use of the unique expression
678 stmtsToAdd.splice( stmtsToAddAfter.end(), dtors[ unqExpr->get_id() ] );
679 } else { // remember dtors for last instance of unique expr
680 dtors[ unqExpr->get_id() ] = fixer.stmtsToAddAfter;
681 }
682 return deref;
683 }
684 return unqExpr;
685 }
686
687 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
688 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
689 // is removed from the ObjectDecl
690 objDecl = dynamic_cast< ObjectDecl * >( Parent::mutate( objDecl ) );
691 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
692 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
693 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
694 if ( Statement * ctor = ctorInit->get_ctor() ) {
695 if ( objDecl->get_storageClasses().is_static ) {
696 // originally wanted to take advantage of gcc nested functions, but
697 // we get memory errors with this approach. To remedy this, the static
698 // variable is hoisted when the destructor needs to be called.
699 //
700 // generate:
701 // static T __objName_static_varN;
702 // void __objName_dtor_atexitN() {
703 // __dtor__...;
704 // }
705 // int f(...) {
706 // ...
707 // static bool __objName_uninitialized = true;
708 // if (__objName_uninitialized) {
709 // __ctor(__objName);
710 // __objName_uninitialized = false;
711 // atexit(__objName_dtor_atexitN);
712 // }
713 // ...
714 // }
715
716 static UniqueName dtorCallerNamer( "_dtor_atexit" );
717
718 // static bool __objName_uninitialized = true
719 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
720 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
721 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", Type::StorageClasses( Type::Static ), LinkageSpec::Cforall, 0, boolType, boolInitExpr );
722 isUninitializedVar->fixUniqueId();
723
724 // __objName_uninitialized = false;
725 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
726 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
727 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
728
729 // generate body of if
730 CompoundStmt * initStmts = new CompoundStmt( noLabels );
731 std::list< Statement * > & body = initStmts->get_kids();
732 body.push_back( ctor );
733 body.push_back( new ExprStmt( noLabels, setTrue ) );
734
735 // put it all together
736 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
737 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
738 stmtsToAddAfter.push_back( ifStmt );
739
740 if ( ctorInit->get_dtor() ) {
741 // if the object has a non-trivial destructor, have to
742 // hoist it and the object into the global space and
743 // call the destructor function with atexit.
744
745 Statement * dtorStmt = ctorInit->get_dtor()->clone();
746
747 // void __objName_dtor_atexitN(...) {...}
748 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), Type::StorageClasses( Type::Static ), LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ) );
749 dtorCaller->fixUniqueId();
750 dtorCaller->get_statements()->push_back( dtorStmt );
751
752 // atexit(dtor_atexit);
753 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
754 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
755
756 body.push_back( new ExprStmt( noLabels, callAtexit ) );
757
758 // hoist variable and dtor caller decls to list of decls that will be added into global scope
759 staticDtorDecls.push_back( objDecl );
760 staticDtorDecls.push_back( dtorCaller );
761
762 // need to rename object uniquely since it now appears
763 // at global scope and there could be multiple function-scoped
764 // static variables with the same name in different functions.
765 // Note: it isn't sufficient to modify only the mangleName, because
766 // then subsequent Indexer passes can choke on seeing the object's name
767 // if another object has the same name and type. An unfortunate side-effect
768 // of renaming the object is that subsequent NameExprs may fail to resolve,
769 // but there shouldn't be any remaining past this point.
770 static UniqueName staticNamer( "_static_var" );
771 objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
772 objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
773
774 objDecl->set_init( NULL );
775 ctorInit->set_ctor( NULL );
776 delete ctorInit;
777
778 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
779 // create a new object which is never used
780 static UniqueName dummyNamer( "_dummy" );
781 ObjectDecl * dummy = new ObjectDecl( dummyNamer.newName(), Type::StorageClasses( Type::Static ), LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), new VoidType( Type::Qualifiers() ) ), 0, std::list< Attribute * >{ new Attribute("unused") } );
782 return dummy;
783 }
784 } else {
785 ImplicitCtorDtorStmt * implicit = safe_dynamic_cast< ImplicitCtorDtorStmt * > ( ctor );
786 ExprStmt * ctorStmt = dynamic_cast< ExprStmt * >( implicit->get_callStmt() );
787 ApplicationExpr * ctorCall = nullptr;
788 if ( ctorStmt && (ctorCall = isIntrinsicCallExpr( ctorStmt->get_expr() )) && ctorCall->get_args().size() == 2 ) {
789 // clean up intrinsic copy constructor calls by making them into SingleInits
790 objDecl->set_init( new SingleInit( ctorCall->get_args().back() ) );
791 ctorCall->get_args().pop_back();
792 } else {
793 stmtsToAddAfter.push_back( ctor );
794 objDecl->set_init( NULL );
795 ctorInit->set_ctor( NULL );
796 }
797 } // if
798 } else if ( Initializer * init = ctorInit->get_init() ) {
799 objDecl->set_init( init );
800 ctorInit->set_init( NULL );
801 } else {
802 // no constructor and no initializer, which is okay
803 objDecl->set_init( NULL );
804 } // if
805 delete ctorInit;
806 } // if
807 return objDecl;
808 }
809
810 void ObjDeclCollector::visit( CompoundStmt * compoundStmt ) {
811 std::set< ObjectDecl * > prevVars = curVars;
812 Parent::visit( compoundStmt );
813 curVars = prevVars;
814 }
815
816 void ObjDeclCollector::visit( DeclStmt * stmt ) {
817 // keep track of all variables currently in scope
818 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
819 curVars.insert( objDecl );
820 } // if
821 Parent::visit( stmt );
822 }
823
824 void LabelFinder::handleStmt( Statement * stmt ) {
825 // for each label, remember the variables in scope at that label.
826 for ( Label l : stmt->get_labels() ) {
827 vars[l] = curVars;
828 } // for
829 }
830
831 template<typename Iterator, typename OutputIterator>
832 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
833 for ( Iterator it = begin ; it != end ; ++it ) {
834 // extract destructor statement from the object decl and insert it into the output. Note that this is
835 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
836 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
837 // contain side effects.
838 ObjectDecl * objDecl = *it;
839 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
840 assert( ctorInit && ctorInit->get_dtor() );
841 *out++ = ctorInit->get_dtor()->clone();
842 } // for
843 }
844
845 void InsertDtors::visit( ObjectDecl * objDecl ) {
846 // remember non-static destructed objects so that their destructors can be inserted later
847 if ( ! objDecl->get_storageClasses().is_static ) {
848 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
849 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
850 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
851 Statement * dtor = ctorInit->get_dtor();
852 if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
853 // don't need to call intrinsic dtor, because it does nothing, but
854 // non-intrinsic dtors must be called
855 reverseDeclOrder.front().push_front( objDecl );
856 } // if
857 } // if
858 } // if
859 Parent::visit( objDecl );
860 }
861
862 template< typename Visitor >
863 void handleFuncDecl( FunctionDecl * funcDecl, Visitor & visitor ) {
864 maybeAccept( funcDecl->get_functionType(), visitor );
865 maybeAccept( funcDecl->get_statements(), visitor );
866 }
867
868 void InsertDtors::visit( FunctionDecl * funcDecl ) {
869 // each function needs to have its own set of labels
870 ValueGuard< LabelFinder::LabelMap > oldLabels( labelVars );
871 labelVars.clear();
872 handleFuncDecl( funcDecl, finder );
873
874 // all labels for this function have been collected, insert destructors as appropriate.
875 // can't be Parent::mutate, because ObjDeclCollector bottoms out on FunctionDecl
876 handleFuncDecl( funcDecl, *this );
877 }
878
879 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
880 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
881 // when block is left, just the destructors associated with variables defined in this block, so push a new
882 // list to the top of the stack so that we can differentiate scopes
883 reverseDeclOrder.push_front( OrderedDecls() );
884 Parent::visit( compoundStmt );
885
886 // add destructors for the current scope that we're exiting
887 std::list< Statement * > & statements = compoundStmt->get_kids();
888 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
889 reverseDeclOrder.pop_front();
890 }
891
892 void InsertDtors::visit( ReturnStmt * returnStmt ) {
893 // return exits all scopes, so dump destructors for all scopes
894 for ( OrderedDecls & od : reverseDeclOrder ) {
895 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
896 } // for
897 }
898
899 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
900 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
901 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
902 // of the error. See C++ Reference 6.6 Jump Statements for details.
903 void InsertDtors::handleGoto( BranchStmt * stmt ) {
904 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
905 // S_L = lvars = set of objects in scope at label definition
906 // S_G = curVars = set of objects in scope at goto statement
907 ObjectSet & lvars = labelVars[ stmt->get_target() ];
908
909 DTOR_PRINT(
910 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
911 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
912 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
913 )
914
915 ObjectSet diff;
916 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
917 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
918 DTOR_PRINT(
919 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
920 )
921 if ( ! diff.empty() ) {
922 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
923 } // if
924 // S_G-S_L results in set of objects that must be destructed
925 diff.clear();
926 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
927 DTOR_PRINT(
928 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
929 )
930 if ( ! diff.empty() ) {
931 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
932 OrderedDecls ordered;
933 for ( OrderedDecls & rdo : reverseDeclOrder ) {
934 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
935 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
936 } // for
937 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
938 } // if
939 }
940
941 void InsertDtors::visit( BranchStmt * stmt ) {
942 switch( stmt->get_type() ) {
943 case BranchStmt::Continue:
944 case BranchStmt::Break:
945 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
946 // always be empty), but it serves as a small sanity check.
947 case BranchStmt::Goto:
948 handleGoto( stmt );
949 break;
950 default:
951 assert( false );
952 } // switch
953 }
954
955 bool checkWarnings( FunctionDecl * funcDecl ) {
956 // only check for warnings if the current function is a user-defined
957 // constructor or destructor
958 if ( ! funcDecl ) return false;
959 if ( ! funcDecl->get_statements() ) return false;
960 return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
961 }
962
963 void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
964 ValueGuard< FunctionDecl * > oldFunction( funcDecl );
965 ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
966 ValueGuard< std::map< DeclarationWithType *, CodeLocation > > oldUsedUninit( usedUninit );
967 ValueGuard< ObjectDecl * > oldThisParam( thisParam );
968 ValueGuard< bool > oldIsCtor( isCtor );
969 ValueGuard< StructDecl * > oldStructDecl( structDecl );
970 errors = SemanticError(); // clear previous errors
971
972 // need to start with fresh sets
973 unhandled.clear();
974 usedUninit.clear();
975
976 function = funcDecl;
977 isCtor = isConstructor( function->get_name() );
978 if ( checkWarnings( function ) ) {
979 FunctionType * type = function->get_functionType();
980 assert( ! type->get_parameters().empty() );
981 thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
982 PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
983 StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
984 if ( structType ) {
985 structDecl = structType->get_baseStruct();
986 for ( Declaration * member : structDecl->get_members() ) {
987 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
988 // record all of the struct type's members that need to be constructed or
989 // destructed by the end of the function
990 unhandled.insert( field );
991 }
992 }
993 }
994 }
995 Parent::visit( function );
996
997 // remove the unhandled objects from usedUninit, because a call is inserted
998 // to handle them - only objects that are later constructed are used uninitialized.
999 std::map< DeclarationWithType *, CodeLocation > diff;
1000 // need the comparator since usedUninit and unhandled have different types
1001 struct comp_t {
1002 typedef decltype(usedUninit)::value_type usedUninit_t;
1003 typedef decltype(unhandled)::value_type unhandled_t;
1004 bool operator()(usedUninit_t x, unhandled_t y) { return x.first < y; }
1005 bool operator()(unhandled_t x, usedUninit_t y) { return x < y.first; }
1006 } comp;
1007 std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ), comp );
1008 for ( auto p : diff ) {
1009 DeclarationWithType * member = p.first;
1010 CodeLocation loc = p.second;
1011 // xxx - make error message better by also tracking the location that the object is constructed at?
1012 emit( loc, "in ", CodeGen::genPrettyType( function->get_functionType(), function->get_name() ), ", field ", member->get_name(), " used before being constructed" );
1013 }
1014
1015 if ( ! unhandled.empty() ) {
1016 // need to explicitly re-add function parameters in order to resolve copy constructors
1017 enterScope();
1018 maybeAccept( function->get_functionType(), *this );
1019
1020 // need to iterate through members in reverse in order for
1021 // ctor/dtor statements to come out in the right order
1022 for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
1023 DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
1024 // skip non-DWT members
1025 if ( ! field ) continue;
1026 // skip handled members
1027 if ( ! unhandled.count( field ) ) continue;
1028
1029 // insert and resolve default/copy constructor call for each field that's unhandled
1030 std::list< Statement * > stmt;
1031 UntypedExpr * deref = UntypedExpr::createDeref( new VariableExpr( thisParam ) );
1032
1033 Expression * arg2 = 0;
1034 if ( isCopyConstructor( function ) ) {
1035 // if copy ctor, need to pass second-param-of-this-function.field
1036 std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
1037 assert( params.size() == 2 );
1038 arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
1039 }
1040 InitExpander srcParam( arg2 );
1041 SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
1042
1043 assert( stmt.size() <= 1 );
1044 if ( stmt.size() == 1 ) {
1045 Statement * callStmt = stmt.front();
1046
1047 MutatingResolver resolver( *this );
1048 try {
1049 callStmt->acceptMutator( resolver );
1050 if ( isCtor ) {
1051 function->get_statements()->push_front( callStmt );
1052 } else {
1053 // destructor statements should be added at the end
1054 function->get_statements()->push_back( callStmt );
1055 }
1056 } catch ( SemanticError & error ) {
1057 emit( funcDecl->location, "in ", CodeGen::genPrettyType( function->get_functionType(), function->get_name() ), ", field ", field->get_name(), " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" );
1058 }
1059 }
1060 }
1061 leaveScope();
1062 }
1063 if (! errors.isEmpty()) {
1064 throw errors;
1065 }
1066 }
1067
1068 void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
1069 if ( ! checkWarnings( function ) ) return;
1070
1071 std::string fname = getFunctionName( appExpr );
1072 if ( fname == function->get_name() ) {
1073 // call to same kind of function
1074 Expression * firstParam = appExpr->get_args().front();
1075
1076 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
1077 // if calling another constructor on thisParam, assume that function handles
1078 // all members - if it doesn't a warning will appear in that function.
1079 if ( varExpr->get_var() == thisParam ) {
1080 unhandled.clear();
1081 }
1082 } else {
1083 // if first parameter is a member expression then
1084 // remove the member from unhandled set.
1085 handleFirstParam( firstParam );
1086 }
1087 }
1088
1089 Parent::visit( appExpr );
1090 }
1091
1092 void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
1093 using namespace std;
1094 if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
1095 if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
1096 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
1097 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
1098 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
1099 if ( varExpr->get_var() == thisParam ) {
1100 unhandled.erase( memberExpr->get_member() );
1101 }
1102 }
1103 }
1104 }
1105 }
1106 }
1107 }
1108
1109 void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
1110 if ( ! checkWarnings( function ) ) return;
1111 if ( ! isCtor ) return;
1112
1113 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
1114 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
1115 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
1116 if ( varExpr->get_var() == thisParam ) {
1117 if ( unhandled.count( memberExpr->get_member() ) ) {
1118 // emit a warning because a member was used before it was constructed
1119 usedUninit.insert( { memberExpr->get_member(), memberExpr->location } );
1120 }
1121 }
1122 }
1123 }
1124 }
1125 Parent::visit( memberExpr );
1126 }
1127
1128 template< typename Visitor, typename... Params >
1129 void error( Visitor & v, CodeLocation loc, const Params &... params ) {
1130 SemanticError err( toString( params... ) );
1131 err.set_location( loc );
1132 v.errors.append( err );
1133 }
1134
1135 template< typename... Params >
1136 void GenStructMemberCalls::emit( CodeLocation loc, const Params &... params ) {
1137 // toggle warnings vs. errors here.
1138 // warn( params... );
1139 error( *this, loc, params... );
1140 }
1141
1142 DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
1143 // add object to the indexer assumes that there will be no name collisions
1144 // in generated code. If this changes, add mutate methods for entities with
1145 // scope and call {enter,leave}Scope explicitly.
1146 objectDecl->accept( indexer );
1147 return objectDecl;
1148 }
1149
1150 Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
1151 return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
1152 }
1153
1154 Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
1155 static UniqueName tempNamer( "_tmp_ctor_expr" );
1156 // xxx - is the size check necessary?
1157 assert( ctorExpr->has_result() && ctorExpr->get_result()->size() == 1 );
1158
1159 // xxx - ideally we would reuse the temporary generated from the copy constructor passes from within firstArg if it exists and not generate a temporary if it's unnecessary.
1160 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), Type::StorageClasses(), LinkageSpec::C, nullptr, ctorExpr->get_result()->clone(), nullptr );
1161 addDeclaration( tmp );
1162
1163 // xxx - this can be TupleAssignExpr now. Need to properly handle this case.
1164 ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
1165 TypeSubstitution * env = ctorExpr->get_env();
1166 ctorExpr->set_callExpr( nullptr );
1167 ctorExpr->set_env( nullptr );
1168
1169 Expression *& firstArg = callExpr->get_args().front();
1170 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
1171 assign->get_args().push_back( new VariableExpr( tmp ) );
1172 assign->get_args().push_back( firstArg );
1173 assign->set_result( ctorExpr->get_result()->clone() );
1174 firstArg = assign;
1175
1176 CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
1177 commaExpr->set_env( env );
1178 delete ctorExpr;
1179 return commaExpr;
1180 }
1181 } // namespace
1182} // namespace InitTweak
1183
1184// Local Variables: //
1185// tab-width: 4 //
1186// mode: c++ //
1187// compile-command: "make install" //
1188// End: //
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