source: src/InitTweak/FixInit.cc@ e883a4b

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 e883a4b was 0661678, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

fix unreachable code warnings
  • Property mode set to 100644
File size: 52.7 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// 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() ) && 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
370 return appExpr;
371 } // if
372 } else if ( isDestructor( funcDecl->get_name() ) ) {
373 // correctness: never copy construct arguments to a destructor
374 return appExpr;
375 } // if
376 } // if
377 } // if
378 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
379
380 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
381 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
382 // save the type substitution into the envMap so that it is easy to find.
383 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
384 // The substitution is needed to obtain the type of temporary variables so that copy constructor
385 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
386 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
387 // saves the environment, or compute the types of temporaries here, but it's much simpler to
388 // save the environment here, and more cohesive to compute temporary variables and resolve copy
389 // constructor calls together.
390 assert( env );
391 envMap[expr] = env;
392 return expr;
393 }
394
395 Expression * InsertImplicitCalls::mutate( StmtExpr * stmtExpr ) {
396 assert( env );
397 envMap[stmtExpr] = env;
398 return Parent::mutate( stmtExpr );
399 }
400
401 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
402 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type ) || Tuples::isTtype( type );
403 }
404
405 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
406 assert( var );
407 // arrays are not copy constructed, so this should always be an ExprStmt
408 ImplicitCtorDtorStmt * stmt = genCtorDtor( fname, var, cpArg );
409 ExprStmt * exprStmt = safe_dynamic_cast< ExprStmt * >( stmt->get_callStmt() );
410 Expression * untyped = exprStmt->get_expr();
411
412 // resolve copy constructor
413 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
414 // (VariableExpr and already resolved expression)
415 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
416 Expression * resolved = ResolvExpr::findVoidExpression( untyped, *this );
417 assert( resolved );
418 if ( resolved->get_env() ) {
419 // Extract useful information and discard new environments. Keeping them causes problems in PolyMutator passes.
420 env->add( *resolved->get_env() );
421 delete resolved->get_env();
422 resolved->set_env( nullptr );
423 } // if
424
425 delete stmt;
426 return resolved;
427 }
428
429 void ResolveCopyCtors::copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr ) {
430 static UniqueName tempNamer("_tmp_cp");
431 assert( env );
432 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *env << std::endl; )
433 assert( arg->has_result() );
434 Type * result = arg->get_result();
435 if ( skipCopyConstruct( result ) ) return; // skip certain non-copyable types
436
437 // type may involve type variables, so apply type substitution to get temporary variable's actual type
438 result = result->clone();
439 env->apply( result );
440 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
441 tmp->get_type()->set_const( false );
442
443 // create and resolve copy constructor
444 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
445 Expression * cpCtor = makeCtorDtor( "?{}", tmp, arg );
446
447 if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( cpCtor ) ) {
448 // if the chosen constructor is intrinsic, the copy is unnecessary, so
449 // don't create the temporary and don't call the copy constructor
450 VariableExpr * function = dynamic_cast< VariableExpr * >( appExpr->get_function() );
451 assert( function );
452 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) return;
453 }
454
455 // replace argument to function call with temporary
456 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
457 impCpCtorExpr->get_tempDecls().push_back( tmp );
458 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
459 }
460
461 void ResolveCopyCtors::destructRet( ObjectDecl * ret, ImplicitCopyCtorExpr * impCpCtorExpr ) {
462 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
463 }
464
465 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
466 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
467 Parent::visit( impCpCtorExpr );
468 env = envMap.at(impCpCtorExpr);
469 assert( env );
470
471 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
472
473 // take each argument and attempt to copy construct it.
474 for ( Expression * & arg : appExpr->get_args() ) {
475 copyConstructArg( arg, impCpCtorExpr );
476 } // for
477
478 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
479 // initialized with the return value and is destructed later
480 // xxx - handle named return values?
481 Type * result = appExpr->get_result();
482 if ( ! result->isVoid() ) {
483 static UniqueName retNamer("_tmp_cp_ret");
484 result = result->clone();
485 env->apply( result );
486 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
487 ret->get_type()->set_const( false );
488 impCpCtorExpr->get_returnDecls().push_back( ret );
489 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
490 if ( ! result->get_lvalue() ) {
491 // destructing lvalue returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary
492 destructRet( ret, impCpCtorExpr );
493 }
494 } // for
495 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
496 }
497
498 void ResolveCopyCtors::visit( StmtExpr * stmtExpr ) {
499 Parent::visit( stmtExpr );
500 env = envMap.at(stmtExpr);
501 assert( stmtExpr->get_result() );
502 Type * result = stmtExpr->get_result();
503 if ( ! result->isVoid() ) {
504 static UniqueName retNamer("_tmp_stmtexpr_ret");
505
506 // create variable that will hold the result of the stmt expr
507 result = result->clone();
508 env->apply( result );
509 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), Type::StorageClasses(), LinkageSpec::C, 0, result, 0 );
510 ret->get_type()->set_const( false );
511 stmtExpr->get_returnDecls().push_front( ret );
512
513 // must have a non-empty body, otherwise it wouldn't have a result
514 CompoundStmt * body = stmtExpr->get_statements();
515 assert( ! body->get_kids().empty() );
516 // must be an ExprStmt, otherwise it wouldn't have a result
517 ExprStmt * last = safe_dynamic_cast< ExprStmt * >( body->get_kids().back() );
518 last->set_expr( makeCtorDtor( "?{}", ret, last->get_expr() ) );
519
520 stmtExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
521 } // if
522
523 }
524
525 void ResolveCopyCtors::visit( UniqueExpr * unqExpr ) {
526 static std::unordered_set< int > vars;
527 unqCount[ unqExpr->get_id() ]++; // count the number of unique expressions for each ID
528 if ( vars.count( unqExpr->get_id() ) ) {
529 // xxx - hack to prevent double-handling of unique exprs, otherwise too many temporary variables and destructors are generated
530 return;
531 }
532
533 Parent::visit( unqExpr );
534 // it should never be necessary to wrap a void-returning expression in a UniqueExpr - if this assumption changes, this needs to be rethought
535 assert( unqExpr->get_result() );
536 if ( ImplicitCopyCtorExpr * impCpCtorExpr = dynamic_cast<ImplicitCopyCtorExpr*>( unqExpr->get_expr() ) ) {
537 // note the variable used as the result from the call
538 assert( impCpCtorExpr->get_result() && impCpCtorExpr->get_returnDecls().size() == 1 );
539 unqExpr->set_var( new VariableExpr( impCpCtorExpr->get_returnDecls().front() ) );
540 } else {
541 // expr isn't a call expr, so create a new temporary variable to use to hold the value of the unique expression
542 unqExpr->set_object( new ObjectDecl( toString("_unq", unqExpr->get_id()), Type::StorageClasses(), LinkageSpec::C, nullptr, unqExpr->get_result()->clone(), nullptr ) );
543 unqExpr->set_var( new VariableExpr( unqExpr->get_object() ) );
544 }
545 vars.insert( unqExpr->get_id() );
546 }
547
548 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
549 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
550
551 impCpCtorExpr = safe_dynamic_cast< ImplicitCopyCtorExpr * >( Parent::mutate( impCpCtorExpr ) );
552 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
553 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
554 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
555
556 // add all temporary declarations and their constructors
557 for ( ObjectDecl * obj : tempDecls ) {
558 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
559 } // for
560 for ( ObjectDecl * obj : returnDecls ) {
561 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
562 } // for
563
564 // add destructors after current statement
565 for ( Expression * dtor : dtors ) {
566 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
567 } // for
568
569 // xxx - update to work with multiple return values
570 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
571 Expression * callExpr = impCpCtorExpr->get_callExpr();
572
573 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
574
575 // detach fields from wrapper node so that it can be deleted without deleting too much
576 dtors.clear();
577 tempDecls.clear();
578 returnDecls.clear();
579 impCpCtorExpr->set_callExpr( NULL );
580 impCpCtorExpr->set_env( NULL );
581 delete impCpCtorExpr;
582
583 if ( returnDecl ) {
584 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
585 assign->get_args().push_back( new VariableExpr( returnDecl ) );
586 assign->get_args().push_back( callExpr );
587 // know the result type of the assignment is the type of the LHS (minus the pointer), so
588 // add that onto the assignment expression so that later steps have the necessary information
589 assign->set_result( returnDecl->get_type()->clone() );
590
591 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
592 if ( callExpr->get_result()->get_lvalue() ) {
593 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
594 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
595 // type of the return temporary from T to T* to properly capture the return value. Then dereference
596 // the result of the comma expression, since the lvalue returning call was originally wrapped with
597 // an AddressExpr. Effectively, this turns
598 // lvalue T f();
599 // &*f();
600 // into
601 // T * f();
602 // T * tmp_cp_retN;
603 // &*(tmp_cp_retN = &*f(), tmp_cp_retN); // the first * and second & are generated here
604 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
605 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
606
607 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
608 retExpr->set_result( new PointerType( Type::Qualifiers(), retExpr->get_result() ) );
609 retExpr = UntypedExpr::createDeref( retExpr );
610 } // if
611 // move env from callExpr to retExpr
612 retExpr->set_env( callExpr->get_env() );
613 callExpr->set_env( nullptr );
614 return retExpr;
615 } else {
616 return callExpr;
617 } // if
618 }
619
620 Expression * FixCopyCtors::mutate( StmtExpr * stmtExpr ) {
621 // function call temporaries should be placed at statement-level, rather than nested inside of a new statement expression,
622 // since temporaries can be shared across sub-expressions, e.g.
623 // [A, A] f();
624 // g([A] x, [A] y);
625 // f(g());
626 // f is executed once, so the return temporary is shared across the tuple constructors for x and y.
627 std::list< Statement * > & stmts = stmtExpr->get_statements()->get_kids();
628 for ( Statement *& stmt : stmts ) {
629 stmt = stmt->acceptMutator( *this );
630 } // for
631 // stmtExpr = safe_dynamic_cast< StmtExpr * >( Parent::mutate( stmtExpr ) );
632 assert( stmtExpr->get_result() );
633 Type * result = stmtExpr->get_result();
634 if ( ! result->isVoid() ) {
635 for ( ObjectDecl * obj : stmtExpr->get_returnDecls() ) {
636 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
637 } // for
638 // add destructors after current statement
639 for ( Expression * dtor : stmtExpr->get_dtors() ) {
640 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
641 } // for
642 // must have a non-empty body, otherwise it wouldn't have a result
643 CompoundStmt * body = stmtExpr->get_statements();
644 assert( ! body->get_kids().empty() );
645 assert( ! stmtExpr->get_returnDecls().empty() );
646 body->get_kids().push_back( new ExprStmt( noLabels, new VariableExpr( stmtExpr->get_returnDecls().front() ) ) );
647 stmtExpr->get_returnDecls().clear();
648 stmtExpr->get_dtors().clear();
649 }
650 assert( stmtExpr->get_returnDecls().empty() );
651 assert( stmtExpr->get_dtors().empty() );
652 return stmtExpr;
653 }
654
655 Expression * FixCopyCtors::mutate( UniqueExpr * unqExpr ) {
656 unqCount[ unqExpr->get_id() ]--;
657 static std::unordered_map< int, std::list< Statement * > > dtors;
658 static std::unordered_map< int, UniqueExpr * > unqMap;
659 static std::unordered_set< int > addDeref;
660 // has to be done to clean up ImplicitCopyCtorExpr nodes, even when this node was skipped in previous passes
661 if ( unqMap.count( unqExpr->get_id() ) ) {
662 // take data from other UniqueExpr to ensure consistency
663 delete unqExpr->get_expr();
664 unqExpr->set_expr( unqMap[unqExpr->get_id()]->get_expr()->clone() );
665 delete unqExpr->get_result();
666 unqExpr->set_result( maybeClone( unqExpr->get_expr()->get_result() ) );
667 if ( unqCount[ unqExpr->get_id() ] == 0 ) { // insert destructor after the last use of the unique expression
668 stmtsToAddAfter.splice( stmtsToAddAfter.end(), dtors[ unqExpr->get_id() ] );
669 }
670 if ( addDeref.count( unqExpr->get_id() ) ) {
671 // other UniqueExpr was dereferenced because it was an lvalue return, so this one should be too
672 return UntypedExpr::createDeref( unqExpr );
673 }
674 return unqExpr;
675 }
676 FixCopyCtors fixer( unqCount );
677 unqExpr->set_expr( unqExpr->get_expr()->acceptMutator( fixer ) ); // stmtexprs contained should not be separately fixed, so this must occur after the lookup
678 stmtsToAdd.splice( stmtsToAdd.end(), fixer.stmtsToAdd );
679 unqMap[unqExpr->get_id()] = unqExpr;
680 if ( unqCount[ unqExpr->get_id() ] == 0 ) { // insert destructor after the last use of the unique expression
681 stmtsToAddAfter.splice( stmtsToAddAfter.end(), dtors[ unqExpr->get_id() ] );
682 } else { // remember dtors for last instance of unique expr
683 dtors[ unqExpr->get_id() ] = fixer.stmtsToAddAfter;
684 }
685 if ( UntypedExpr * deref = dynamic_cast< UntypedExpr * >( unqExpr->get_expr() ) ) {
686 // unique expression is now a dereference, because the inner expression is an lvalue returning function call.
687 // Normalize the expression by dereferencing the unique expression, rather than the inner expression
688 // (i.e. move the dereference out a level)
689 assert( getFunctionName( deref ) == "*?" );
690 unqExpr->set_expr( getCallArg( deref, 0 ) );
691 getCallArg( deref, 0 ) = unqExpr;
692 addDeref.insert( unqExpr->get_id() );
693 return deref;
694 }
695 return unqExpr;
696 }
697
698 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
699 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
700 // is removed from the ObjectDecl
701 objDecl = dynamic_cast< ObjectDecl * >( Parent::mutate( objDecl ) );
702 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
703 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
704 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
705 if ( Statement * ctor = ctorInit->get_ctor() ) {
706 if ( objDecl->get_storageClasses().is_static ) {
707 // originally wanted to take advantage of gcc nested functions, but
708 // we get memory errors with this approach. To remedy this, the static
709 // variable is hoisted when the destructor needs to be called.
710 //
711 // generate:
712 // static T __objName_static_varN;
713 // void __objName_dtor_atexitN() {
714 // __dtor__...;
715 // }
716 // int f(...) {
717 // ...
718 // static bool __objName_uninitialized = true;
719 // if (__objName_uninitialized) {
720 // __ctor(__objName);
721 // __objName_uninitialized = false;
722 // atexit(__objName_dtor_atexitN);
723 // }
724 // ...
725 // }
726
727 static UniqueName dtorCallerNamer( "_dtor_atexit" );
728
729 // static bool __objName_uninitialized = true
730 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
731 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
732 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", Type::StorageClasses( Type::Static ), LinkageSpec::Cforall, 0, boolType, boolInitExpr );
733 isUninitializedVar->fixUniqueId();
734
735 // __objName_uninitialized = false;
736 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
737 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
738 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
739
740 // generate body of if
741 CompoundStmt * initStmts = new CompoundStmt( noLabels );
742 std::list< Statement * > & body = initStmts->get_kids();
743 body.push_back( ctor );
744 body.push_back( new ExprStmt( noLabels, setTrue ) );
745
746 // put it all together
747 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
748 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
749 stmtsToAddAfter.push_back( ifStmt );
750
751 Statement * dtor = ctorInit->get_dtor();
752 objDecl->set_init( NULL );
753 ctorInit->set_ctor( NULL );
754 ctorInit->set_dtor( nullptr );
755 if ( dtor ) {
756 // if the object has a non-trivial destructor, have to
757 // hoist it and the object into the global space and
758 // call the destructor function with atexit.
759
760 Statement * dtorStmt = dtor->clone();
761
762 // void __objName_dtor_atexitN(...) {...}
763 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), Type::StorageClasses( Type::Static ), LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ) );
764 dtorCaller->fixUniqueId();
765 dtorCaller->get_statements()->push_back( dtorStmt );
766
767 // atexit(dtor_atexit);
768 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
769 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
770
771 body.push_back( new ExprStmt( noLabels, callAtexit ) );
772
773 // hoist variable and dtor caller decls to list of decls that will be added into global scope
774 staticDtorDecls.push_back( objDecl );
775 staticDtorDecls.push_back( dtorCaller );
776
777 // need to rename object uniquely since it now appears
778 // at global scope and there could be multiple function-scoped
779 // static variables with the same name in different functions.
780 // Note: it isn't sufficient to modify only the mangleName, because
781 // then subsequent Indexer passes can choke on seeing the object's name
782 // if another object has the same name and type. An unfortunate side-effect
783 // of renaming the object is that subsequent NameExprs may fail to resolve,
784 // but there shouldn't be any remaining past this point.
785 static UniqueName staticNamer( "_static_var" );
786 objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
787 objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
788
789 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
790 // create a new object which is never used
791 static UniqueName dummyNamer( "_dummy" );
792 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") } );
793 delete ctorInit;
794 return dummy;
795 }
796 } else {
797 ImplicitCtorDtorStmt * implicit = safe_dynamic_cast< ImplicitCtorDtorStmt * > ( ctor );
798 ExprStmt * ctorStmt = dynamic_cast< ExprStmt * >( implicit->get_callStmt() );
799 ApplicationExpr * ctorCall = nullptr;
800 if ( ctorStmt && (ctorCall = isIntrinsicCallExpr( ctorStmt->get_expr() )) && ctorCall->get_args().size() == 2 ) {
801 // clean up intrinsic copy constructor calls by making them into SingleInits
802 objDecl->set_init( new SingleInit( ctorCall->get_args().back() ) );
803 ctorCall->get_args().pop_back();
804 } else {
805 stmtsToAddAfter.push_back( ctor );
806 objDecl->set_init( NULL );
807 ctorInit->set_ctor( NULL );
808 }
809 } // if
810 } else if ( Initializer * init = ctorInit->get_init() ) {
811 objDecl->set_init( init );
812 ctorInit->set_init( NULL );
813 } else {
814 // no constructor and no initializer, which is okay
815 objDecl->set_init( NULL );
816 } // if
817 delete ctorInit;
818 } // if
819 return objDecl;
820 }
821
822 void ObjDeclCollector::visit( CompoundStmt * compoundStmt ) {
823 std::set< ObjectDecl * > prevVars = curVars;
824 Parent::visit( compoundStmt );
825 curVars = prevVars;
826 }
827
828 void ObjDeclCollector::visit( DeclStmt * stmt ) {
829 // keep track of all variables currently in scope
830 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
831 curVars.insert( objDecl );
832 } // if
833 Parent::visit( stmt );
834 }
835
836 void LabelFinder::handleStmt( Statement * stmt ) {
837 // for each label, remember the variables in scope at that label.
838 for ( Label l : stmt->get_labels() ) {
839 vars[l] = curVars;
840 } // for
841 }
842
843 template<typename Iterator, typename OutputIterator>
844 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
845 for ( Iterator it = begin ; it != end ; ++it ) {
846 // extract destructor statement from the object decl and insert it into the output. Note that this is
847 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
848 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
849 // contain side effects.
850 ObjectDecl * objDecl = *it;
851 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
852 assert( ctorInit && ctorInit->get_dtor() );
853 *out++ = ctorInit->get_dtor()->clone();
854 } // for
855 }
856
857 void InsertDtors::visit( ObjectDecl * objDecl ) {
858 // remember non-static destructed objects so that their destructors can be inserted later
859 if ( ! objDecl->get_storageClasses().is_static ) {
860 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
861 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
862 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
863 Statement * dtor = ctorInit->get_dtor();
864 if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
865 // don't need to call intrinsic dtor, because it does nothing, but
866 // non-intrinsic dtors must be called
867 reverseDeclOrder.front().push_front( objDecl );
868 } // if
869 } // if
870 } // if
871 Parent::visit( objDecl );
872 }
873
874 template< typename Visitor >
875 void handleFuncDecl( FunctionDecl * funcDecl, Visitor & visitor ) {
876 maybeAccept( funcDecl->get_functionType(), visitor );
877 maybeAccept( funcDecl->get_statements(), visitor );
878 }
879
880 void InsertDtors::visit( FunctionDecl * funcDecl ) {
881 // each function needs to have its own set of labels
882 ValueGuard< LabelFinder::LabelMap > oldLabels( labelVars );
883 labelVars.clear();
884 handleFuncDecl( funcDecl, finder );
885
886 // all labels for this function have been collected, insert destructors as appropriate.
887 // can't be Parent::mutate, because ObjDeclCollector bottoms out on FunctionDecl
888 handleFuncDecl( funcDecl, *this );
889 }
890
891 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
892 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
893 // when block is left, just the destructors associated with variables defined in this block, so push a new
894 // list to the top of the stack so that we can differentiate scopes
895 reverseDeclOrder.push_front( OrderedDecls() );
896 Parent::visit( compoundStmt );
897
898 // add destructors for the current scope that we're exiting, unless the last statement is a return, which
899 // causes unreachable code warnings
900 std::list< Statement * > & statements = compoundStmt->get_kids();
901 if ( ! statements.empty() && ! dynamic_cast< ReturnStmt * >( statements.back() ) ) {
902 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
903 }
904 reverseDeclOrder.pop_front();
905 }
906
907 void InsertDtors::visit( ReturnStmt * returnStmt ) {
908 // return exits all scopes, so dump destructors for all scopes
909 for ( OrderedDecls & od : reverseDeclOrder ) {
910 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
911 } // for
912 }
913
914 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
915 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
916 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
917 // of the error. See C++ Reference 6.6 Jump Statements for details.
918 void InsertDtors::handleGoto( BranchStmt * stmt ) {
919 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
920 // S_L = lvars = set of objects in scope at label definition
921 // S_G = curVars = set of objects in scope at goto statement
922 ObjectSet & lvars = labelVars[ stmt->get_target() ];
923
924 DTOR_PRINT(
925 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
926 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
927 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
928 )
929
930 ObjectSet diff;
931 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
932 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
933 DTOR_PRINT(
934 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
935 )
936 if ( ! diff.empty() ) {
937 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
938 } // if
939 // S_G-S_L results in set of objects that must be destructed
940 diff.clear();
941 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
942 DTOR_PRINT(
943 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
944 )
945 if ( ! diff.empty() ) {
946 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
947 OrderedDecls ordered;
948 for ( OrderedDecls & rdo : reverseDeclOrder ) {
949 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
950 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
951 } // for
952 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
953 } // if
954 }
955
956 void InsertDtors::visit( BranchStmt * stmt ) {
957 switch( stmt->get_type() ) {
958 case BranchStmt::Continue:
959 case BranchStmt::Break:
960 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
961 // always be empty), but it serves as a small sanity check.
962 case BranchStmt::Goto:
963 handleGoto( stmt );
964 break;
965 default:
966 assert( false );
967 } // switch
968 }
969
970 bool checkWarnings( FunctionDecl * funcDecl ) {
971 // only check for warnings if the current function is a user-defined
972 // constructor or destructor
973 if ( ! funcDecl ) return false;
974 if ( ! funcDecl->get_statements() ) return false;
975 return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
976 }
977
978 void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
979 ValueGuard< FunctionDecl * > oldFunction( funcDecl );
980 ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
981 ValueGuard< std::map< DeclarationWithType *, CodeLocation > > oldUsedUninit( usedUninit );
982 ValueGuard< ObjectDecl * > oldThisParam( thisParam );
983 ValueGuard< bool > oldIsCtor( isCtor );
984 ValueGuard< StructDecl * > oldStructDecl( structDecl );
985 errors = SemanticError(); // clear previous errors
986
987 // need to start with fresh sets
988 unhandled.clear();
989 usedUninit.clear();
990
991 function = funcDecl;
992 isCtor = isConstructor( function->get_name() );
993 if ( checkWarnings( function ) ) {
994 FunctionType * type = function->get_functionType();
995 assert( ! type->get_parameters().empty() );
996 thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
997 PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
998 StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
999 if ( structType ) {
1000 structDecl = structType->get_baseStruct();
1001 for ( Declaration * member : structDecl->get_members() ) {
1002 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
1003 // record all of the struct type's members that need to be constructed or
1004 // destructed by the end of the function
1005 unhandled.insert( field );
1006 }
1007 }
1008 }
1009 }
1010 Parent::visit( function );
1011
1012 // remove the unhandled objects from usedUninit, because a call is inserted
1013 // to handle them - only objects that are later constructed are used uninitialized.
1014 std::map< DeclarationWithType *, CodeLocation > diff;
1015 // need the comparator since usedUninit and unhandled have different types
1016 struct comp_t {
1017 typedef decltype(usedUninit)::value_type usedUninit_t;
1018 typedef decltype(unhandled)::value_type unhandled_t;
1019 bool operator()(usedUninit_t x, unhandled_t y) { return x.first < y; }
1020 bool operator()(unhandled_t x, usedUninit_t y) { return x < y.first; }
1021 } comp;
1022 std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ), comp );
1023 for ( auto p : diff ) {
1024 DeclarationWithType * member = p.first;
1025 CodeLocation loc = p.second;
1026 // xxx - make error message better by also tracking the location that the object is constructed at?
1027 emit( loc, "in ", CodeGen::genPrettyType( function->get_functionType(), function->get_name() ), ", field ", member->get_name(), " used before being constructed" );
1028 }
1029
1030 if ( ! unhandled.empty() ) {
1031 // need to explicitly re-add function parameters in order to resolve copy constructors
1032 enterScope();
1033 maybeAccept( function->get_functionType(), *this );
1034
1035 // need to iterate through members in reverse in order for
1036 // ctor/dtor statements to come out in the right order
1037 for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
1038 DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
1039 // skip non-DWT members
1040 if ( ! field ) continue;
1041 // skip handled members
1042 if ( ! unhandled.count( field ) ) continue;
1043
1044 // insert and resolve default/copy constructor call for each field that's unhandled
1045 std::list< Statement * > stmt;
1046 UntypedExpr * deref = UntypedExpr::createDeref( new VariableExpr( thisParam ) );
1047
1048 Expression * arg2 = 0;
1049 if ( isCopyConstructor( function ) ) {
1050 // if copy ctor, need to pass second-param-of-this-function.field
1051 std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
1052 assert( params.size() == 2 );
1053 arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
1054 }
1055 InitExpander srcParam( arg2 );
1056 SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
1057
1058 assert( stmt.size() <= 1 );
1059 if ( stmt.size() == 1 ) {
1060 Statement * callStmt = stmt.front();
1061
1062 MutatingResolver resolver( *this );
1063 try {
1064 callStmt->acceptMutator( resolver );
1065 if ( isCtor ) {
1066 function->get_statements()->push_front( callStmt );
1067 } else {
1068 // destructor statements should be added at the end
1069 function->get_statements()->push_back( callStmt );
1070 }
1071 } catch ( SemanticError & error ) {
1072 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" );
1073 }
1074 }
1075 }
1076 leaveScope();
1077 }
1078 if (! errors.isEmpty()) {
1079 throw errors;
1080 }
1081 }
1082
1083 void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
1084 if ( ! checkWarnings( function ) ) return;
1085
1086 std::string fname = getFunctionName( appExpr );
1087 if ( fname == function->get_name() ) {
1088 // call to same kind of function
1089 Expression * firstParam = appExpr->get_args().front();
1090
1091 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
1092 // if calling another constructor on thisParam, assume that function handles
1093 // all members - if it doesn't a warning will appear in that function.
1094 if ( varExpr->get_var() == thisParam ) {
1095 unhandled.clear();
1096 }
1097 } else {
1098 // if first parameter is a member expression then
1099 // remove the member from unhandled set.
1100 handleFirstParam( firstParam );
1101 }
1102 }
1103
1104 Parent::visit( appExpr );
1105 }
1106
1107 void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
1108 using namespace std;
1109 if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
1110 if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
1111 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
1112 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
1113 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
1114 if ( varExpr->get_var() == thisParam ) {
1115 unhandled.erase( memberExpr->get_member() );
1116 }
1117 }
1118 }
1119 }
1120 }
1121 }
1122 }
1123
1124 void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
1125 if ( ! checkWarnings( function ) ) return;
1126 if ( ! isCtor ) return;
1127
1128 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
1129 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
1130 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
1131 if ( varExpr->get_var() == thisParam ) {
1132 if ( unhandled.count( memberExpr->get_member() ) ) {
1133 // emit a warning because a member was used before it was constructed
1134 usedUninit.insert( { memberExpr->get_member(), memberExpr->location } );
1135 }
1136 }
1137 }
1138 }
1139 }
1140 Parent::visit( memberExpr );
1141 }
1142
1143 template< typename Visitor, typename... Params >
1144 void error( Visitor & v, CodeLocation loc, const Params &... params ) {
1145 SemanticError err( toString( params... ) );
1146 err.set_location( loc );
1147 v.errors.append( err );
1148 }
1149
1150 template< typename... Params >
1151 void GenStructMemberCalls::emit( CodeLocation loc, const Params &... params ) {
1152 // toggle warnings vs. errors here.
1153 // warn( params... );
1154 error( *this, loc, params... );
1155 }
1156
1157 DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
1158 // add object to the indexer assumes that there will be no name collisions
1159 // in generated code. If this changes, add mutate methods for entities with
1160 // scope and call {enter,leave}Scope explicitly.
1161 objectDecl->accept( indexer );
1162 return objectDecl;
1163 }
1164
1165 Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
1166 return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
1167 }
1168
1169 Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
1170 static UniqueName tempNamer( "_tmp_ctor_expr" );
1171 // xxx - is the size check necessary?
1172 assert( ctorExpr->has_result() && ctorExpr->get_result()->size() == 1 );
1173
1174 // 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.
1175 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), Type::StorageClasses(), LinkageSpec::C, nullptr, ctorExpr->get_result()->clone(), nullptr );
1176 addDeclaration( tmp );
1177
1178 // xxx - this can be TupleAssignExpr now. Need to properly handle this case.
1179 ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
1180 TypeSubstitution * env = ctorExpr->get_env();
1181 ctorExpr->set_callExpr( nullptr );
1182 ctorExpr->set_env( nullptr );
1183
1184 Expression *& firstArg = callExpr->get_args().front();
1185 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
1186 assign->get_args().push_back( new VariableExpr( tmp ) );
1187 assign->get_args().push_back( firstArg );
1188 assign->set_result( ctorExpr->get_result()->clone() );
1189 firstArg = assign;
1190
1191 CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
1192 commaExpr->set_env( env );
1193 delete ctorExpr;
1194 return commaExpr;
1195 }
1196 } // namespace
1197} // namespace InitTweak
1198
1199// Local Variables: //
1200// tab-width: 4 //
1201// mode: c++ //
1202// compile-command: "make install" //
1203// End: //
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