source: src/InitTweak/FixInit.cc@ b6fd751

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 b6fd751 was f0121d7, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

refactor genCtorInit, generate ConstructorInit for UniqueExpr
  • Property mode set to 100644
File size: 42.2 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 : Tue Jul 12 17:41:15 2016
13// Update Count : 34
14//
15
16#include <stack>
17#include <list>
18#include <iterator>
19#include <algorithm>
20#include "InitTweak.h"
21#include "FixInit.h"
22#include "FixGlobalInit.h"
23#include "ResolvExpr/Resolver.h"
24#include "ResolvExpr/typeops.h"
25#include "SynTree/Declaration.h"
26#include "SynTree/Type.h"
27#include "SynTree/Expression.h"
28#include "SynTree/Attribute.h"
29#include "SynTree/Statement.h"
30#include "SynTree/Initializer.h"
31#include "SynTree/Mutator.h"
32#include "SymTab/Indexer.h"
33#include "SymTab/Autogen.h"
34#include "GenPoly/PolyMutator.h"
35#include "GenPoly/DeclMutator.h"
36#include "SynTree/AddStmtVisitor.h"
37#include "CodeGen/GenType.h" // for warning/error messages
38
39bool ctordtorp = false; // print all debug
40bool ctorp = false; // print ctor debug
41bool cpctorp = false; // print copy ctor debug
42bool dtorp = false; // print dtor debug
43#define PRINT( text ) if ( ctordtorp ) { text }
44#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
45#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
46
47namespace InitTweak {
48 namespace {
49 class InsertImplicitCalls : public GenPoly::PolyMutator {
50 public:
51 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
52 /// function calls need their parameters to be copy constructed
53 static void insert( std::list< Declaration * > & translationUnit );
54
55 virtual Expression * mutate( ApplicationExpr * appExpr );
56 };
57
58 class ResolveCopyCtors : public SymTab::Indexer {
59 public:
60 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
61 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
62 /// arguments and return value temporaries
63 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
64
65 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
66
67 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
68 Expression * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
69 Expression * makeCtorDtor( const std::string & fname, Expression * thisArg, Expression * cpArg = NULL );
70 /// true if type does not need to be copy constructed to ensure correctness
71 bool skipCopyConstruct( Type * type );
72 void copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr );
73 void destructRet( Expression * ret, ImplicitCopyCtorExpr * impCpCtorExpr );
74 private:
75 TypeSubstitution * env;
76 };
77
78 /// collects constructed object decls - used as a base class
79 class ObjDeclCollector : public AddStmtVisitor {
80 public:
81 typedef AddStmtVisitor Parent;
82 using Parent::visit;
83 typedef std::set< ObjectDecl * > ObjectSet;
84 virtual void visit( CompoundStmt *compoundStmt );
85 virtual void visit( DeclStmt *stmt );
86 protected:
87 ObjectSet curVars;
88 };
89
90 // debug
91 struct printSet {
92 typedef ObjDeclCollector::ObjectSet ObjectSet;
93 printSet( const ObjectSet & objs ) : objs( objs ) {}
94 const ObjectSet & objs;
95 };
96 std::ostream & operator<<( std::ostream & out, const printSet & set) {
97 out << "{ ";
98 for ( ObjectDecl * obj : set.objs ) {
99 out << obj->get_name() << ", " ;
100 } // for
101 out << " }";
102 return out;
103 }
104
105 class LabelFinder : public ObjDeclCollector {
106 public:
107 typedef ObjDeclCollector Parent;
108 typedef std::map< Label, ObjectSet > LabelMap;
109 // map of Label -> live variables at that label
110 LabelMap vars;
111
112 void handleStmt( Statement * stmt );
113
114 // xxx - This needs to be done better.
115 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
116 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
117 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
118 // every specialized class knows about every new kind of statement that might be added.
119 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
133 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
134 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
135 };
136
137 class InsertDtors : public ObjDeclCollector {
138 public:
139 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
140 /// (currently by FixInit)
141 static void insert( std::list< Declaration * > & translationUnit );
142
143 typedef ObjDeclCollector Parent;
144 typedef std::list< ObjectDecl * > OrderedDecls;
145 typedef std::list< OrderedDecls > OrderedDeclsStack;
146
147 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
148
149 virtual void visit( ObjectDecl * objDecl );
150
151 virtual void visit( CompoundStmt * compoundStmt );
152 virtual void visit( ReturnStmt * returnStmt );
153 virtual void visit( BranchStmt * stmt );
154 private:
155 void handleGoto( BranchStmt * stmt );
156
157 LabelFinder::LabelMap & labelVars;
158 OrderedDeclsStack reverseDeclOrder;
159 };
160
161 class FixInit : public GenPoly::PolyMutator {
162 public:
163 /// expand each object declaration to use its constructor after it is declared.
164 static void fixInitializers( std::list< Declaration * > &translationUnit );
165
166 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
167
168 std::list< Declaration * > staticDtorDecls;
169 };
170
171 class FixCopyCtors : public GenPoly::PolyMutator {
172 public:
173 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
174 /// and destructors
175 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
176
177 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
178 };
179
180 class GenStructMemberCalls : public SymTab::Indexer {
181 public:
182 typedef Indexer Parent;
183 /// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
184 /// for any member that is missing a corresponding ctor/dtor call.
185 /// error if a member is used before constructed
186 static void generate( std::list< Declaration * > & translationUnit );
187
188 virtual void visit( FunctionDecl * funcDecl );
189
190 virtual void visit( MemberExpr * memberExpr );
191 virtual void visit( ApplicationExpr * appExpr );
192
193 SemanticError errors;
194 private:
195 void handleFirstParam( Expression * firstParam );
196 template< typename... Params >
197 void emit( const Params &... params );
198
199 FunctionDecl * function = 0;
200 std::set< DeclarationWithType * > unhandled, usedUninit;
201 ObjectDecl * thisParam = 0;
202 bool isCtor = false; // true if current function is a constructor
203 StructDecl * structDecl = 0;
204 };
205
206 // very simple resolver-like mutator class - used to
207 // resolve UntypedExprs that are found within newly
208 // generated constructor/destructor calls
209 class MutatingResolver : public Mutator {
210 public:
211 MutatingResolver( SymTab::Indexer & indexer ) : indexer( indexer ) {}
212
213 virtual DeclarationWithType* mutate( ObjectDecl *objectDecl );
214
215 virtual Expression* mutate( UntypedExpr *untypedExpr );
216 private:
217 SymTab::Indexer & indexer;
218 };
219
220 class FixCtorExprs : public GenPoly::DeclMutator {
221 public:
222 /// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
223 static void fix( std::list< Declaration * > & translationUnit );
224
225 virtual Expression * mutate( ConstructorExpr * ctorExpr );
226 };
227 } // namespace
228
229 void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
230 // fixes ConstructorInit for global variables. should happen before fixInitializers.
231 InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
232
233
234 InsertImplicitCalls::insert( translationUnit );
235 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
236 InsertDtors::insert( translationUnit );
237 FixInit::fixInitializers( translationUnit );
238
239 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
240 FixCopyCtors::fixCopyCtors( translationUnit );
241
242 GenStructMemberCalls::generate( translationUnit );
243 // xxx - ctor expansion currently has to be after FixCopyCtors, because there is currently a
244 // hack in the way untyped assignments are generated, where the first argument cannot have
245 // its address taken because of the way codegeneration handles UntypedExpr vs. ApplicationExpr.
246 // Thus such assignment exprs must never pushed through expression resolution (and thus should
247 // not go through the FixCopyCtors pass), otherwise they will fail -- guaranteed.
248 // Also needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
249 // don't look right, and a member can be constructed more than once.
250 FixCtorExprs::fix( translationUnit );
251 }
252
253 namespace {
254 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
255 InsertImplicitCalls inserter;
256 mutateAll( translationUnit, inserter );
257 }
258
259 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
260 ResolveCopyCtors resolver;
261 acceptAll( translationUnit, resolver );
262 }
263
264 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
265 FixInit fixer;
266
267 // can't use mutateAll, because need to insert declarations at top-level
268 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
269 SemanticError errors;
270 for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
271 try {
272 *i = maybeMutate( *i, fixer );
273 translationUnit.splice( i, fixer.staticDtorDecls );
274 } catch( SemanticError &e ) {
275 errors.append( e );
276 } // try
277 } // for
278 if ( ! errors.isEmpty() ) {
279 throw errors;
280 } // if
281 }
282
283 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
284 LabelFinder finder;
285 InsertDtors inserter( finder );
286 acceptAll( translationUnit, finder );
287 acceptAll( translationUnit, inserter );
288 }
289
290 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
291 FixCopyCtors fixer;
292 mutateAll( translationUnit, fixer );
293 }
294
295 void GenStructMemberCalls::generate( std::list< Declaration * > & translationUnit ) {
296 GenStructMemberCalls warner;
297 acceptAll( translationUnit, warner );
298
299 // visitor doesn't throw so that it can collect all errors
300 if ( ! warner.errors.isEmpty() ) {
301 throw warner.errors;
302 }
303 }
304
305 void FixCtorExprs::fix( std::list< Declaration * > & translationUnit ) {
306 FixCtorExprs fixer;
307 fixer.mutateDeclarationList( translationUnit );
308 }
309
310 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
311 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
312 assert( appExpr );
313
314 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
315 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
316 // optimization: don't need to copy construct in order to call intrinsic functions
317 return appExpr;
318 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
319 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
320 assert( ftype );
321 if ( (isConstructor( funcDecl->get_name() ) || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
322 Type * t1 = ftype->get_parameters().front()->get_type();
323 Type * t2 = ftype->get_parameters().back()->get_type();
324 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
325 assert( ptrType );
326
327 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
328 // optimization: don't need to copy construct in order to call a copy constructor or
329 // assignment operator
330 return appExpr;
331 } // if
332 } else if ( isDestructor( funcDecl->get_name() ) ) {
333 // correctness: never copy construct arguments to a destructor
334 return appExpr;
335 } // if
336 } // if
337 } // if
338 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
339
340 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
341 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
342 // save the type substitution onto the new node so that it is easy to find.
343 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
344 // The substitution is needed to obtain the type of temporary variables so that copy constructor
345 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
346 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
347 // saves the environment, or compute the types of temporaries here, but it's much simpler to
348 // save the environment here, and more cohesive to compute temporary variables and resolve copy
349 // constructor calls together.
350 assert( env );
351 expr->set_env( env );
352 return expr;
353 }
354
355 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
356 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
357 }
358
359 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
360 assert( var );
361 return makeCtorDtor( fname, new AddressExpr( new VariableExpr( var ) ), cpArg );
362 }
363
364 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, Expression * thisArg, Expression * cpArg ) {
365 assert( thisArg );
366 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
367 untyped->get_args().push_back( thisArg );
368 if (cpArg) untyped->get_args().push_back( cpArg->clone() );
369
370 // resolve copy constructor
371 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
372 // (VariableExpr and already resolved expression)
373 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
374 Expression * resolved = ResolvExpr::findVoidExpression( untyped, *this );
375 assert( resolved );
376 if ( resolved->get_env() ) {
377 env->add( *resolved->get_env() );
378 } // if
379
380 delete untyped;
381 return resolved;
382 }
383
384 void ResolveCopyCtors::copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr ) {
385 static UniqueName tempNamer("_tmp_cp");
386 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
387 assert( arg->has_result() );
388 Type * result = arg->get_result();
389 if ( skipCopyConstruct( result ) ) return; // skip certain non-copyable types
390
391 // type may involve type variables, so apply type substitution to get temporary variable's actual type
392 result = result->clone();
393 impCpCtorExpr->get_env()->apply( result );
394 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
395 tmp->get_type()->set_isConst( false );
396
397 // create and resolve copy constructor
398 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
399 Expression * cpCtor = makeCtorDtor( "?{}", tmp, arg );
400
401 if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( cpCtor ) ) {
402 // if the chosen constructor is intrinsic, the copy is unnecessary, so
403 // don't create the temporary and don't call the copy constructor
404 VariableExpr * function = dynamic_cast< VariableExpr * >( appExpr->get_function() );
405 assert( function );
406 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) return;
407 }
408
409 // replace argument to function call with temporary
410 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
411 impCpCtorExpr->get_tempDecls().push_back( tmp );
412 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
413 }
414
415 void ResolveCopyCtors::destructRet( Expression * ret, ImplicitCopyCtorExpr * impCpCtorExpr ) {
416 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", new AddressExpr( ret ) ) );
417 }
418
419 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
420 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
421 Visitor::visit( impCpCtorExpr );
422 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
423
424 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
425
426 // take each argument and attempt to copy construct it.
427 for ( Expression * & arg : appExpr->get_args() ) {
428 copyConstructArg( arg, impCpCtorExpr );
429 } // for
430
431 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
432 // initialized with the return value and is destructed later
433 // xxx - handle multiple return values
434 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
435 // xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
436 // level. Trying to pass that environment along.
437 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
438 Type * result = appExpr->get_result();
439 if ( ! result->isVoid() ) {
440 static UniqueName retNamer("_tmp_cp_ret");
441 result = result->clone();
442 impCpCtorExpr->get_env()->apply( result );
443 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
444 ret->get_type()->set_isConst( false );
445 impCpCtorExpr->get_returnDecls().push_back( ret );
446 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
447 destructRet( new VariableExpr( ret ) , impCpCtorExpr );
448 } // for
449 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
450 }
451
452
453 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
454 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
455
456 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
457 assert( impCpCtorExpr );
458
459 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
460 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
461 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
462
463 // add all temporary declarations and their constructors
464 for ( ObjectDecl * obj : tempDecls ) {
465 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
466 } // for
467 for ( ObjectDecl * obj : returnDecls ) {
468 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
469 } // for
470
471 // add destructors after current statement
472 for ( Expression * dtor : dtors ) {
473 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
474 } // for
475
476 // xxx - update to work with multiple return values
477 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
478 Expression * callExpr = impCpCtorExpr->get_callExpr();
479
480 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
481
482 // detach fields from wrapper node so that it can be deleted without deleting too much
483 dtors.clear();
484 tempDecls.clear();
485 returnDecls.clear();
486 impCpCtorExpr->set_callExpr( NULL );
487 impCpCtorExpr->set_env( NULL );
488 delete impCpCtorExpr;
489
490 if ( returnDecl ) {
491 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
492 assign->get_args().push_back( new VariableExpr( returnDecl ) );
493 assign->get_args().push_back( callExpr );
494 // know the result type of the assignment is the type of the LHS (minus the pointer), so
495 // add that onto the assignment expression so that later steps have the necessary information
496 assign->set_result( returnDecl->get_type()->clone() );
497
498 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
499 if ( callExpr->get_result()->get_isLvalue() ) {
500 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
501 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
502 // type of the return temporary from T to T* to properly capture the return value. Then dereference
503 // the result of the comma expression, since the lvalue returning call was originally wrapped with
504 // an AddressExpr. Effectively, this turns
505 // lvalue T f();
506 // &*f()
507 // into
508 // T * tmp_cp_retN;
509 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
510 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
511 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
512
513 Type * resultType = returnDecl->get_type()->clone();
514 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
515 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
516 deref->get_args().push_back( retExpr );
517 deref->set_result( resultType );
518 retExpr = deref;
519 } // if
520 retExpr->set_env( env->clone() );
521 return retExpr;
522 } else {
523 return callExpr;
524 } // if
525 }
526
527 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
528 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
529 // is removed from the ObjectDecl
530 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
531
532 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
533 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
534 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
535 if ( Statement * ctor = ctorInit->get_ctor() ) {
536 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
537 // originally wanted to take advantage of gcc nested functions, but
538 // we get memory errors with this approach. To remedy this, the static
539 // variable is hoisted when the destructor needs to be called.
540 //
541 // generate:
542 // static T __objName_static_varN;
543 // void __objName_dtor_atexitN() {
544 // __dtor__...;
545 // }
546 // int f(...) {
547 // ...
548 // static bool __objName_uninitialized = true;
549 // if (__objName_uninitialized) {
550 // __ctor(__objName);
551 // __objName_uninitialized = false;
552 // atexit(__objName_dtor_atexitN);
553 // }
554 // ...
555 // }
556
557 static UniqueName dtorCallerNamer( "_dtor_atexit" );
558
559 // static bool __objName_uninitialized = true
560 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
561 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
562 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
563 isUninitializedVar->fixUniqueId();
564
565 // __objName_uninitialized = false;
566 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
567 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
568 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
569
570 // generate body of if
571 CompoundStmt * initStmts = new CompoundStmt( noLabels );
572 std::list< Statement * > & body = initStmts->get_kids();
573 body.push_back( ctor );
574 body.push_back( new ExprStmt( noLabels, setTrue ) );
575
576 // put it all together
577 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
578 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
579 stmtsToAddAfter.push_back( ifStmt );
580
581 if ( ctorInit->get_dtor() ) {
582 // if the object has a non-trivial destructor, have to
583 // hoist it and the object into the global space and
584 // call the destructor function with atexit.
585
586 Statement * dtorStmt = ctorInit->get_dtor()->clone();
587
588 // void __objName_dtor_atexitN(...) {...}
589 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
590 dtorCaller->fixUniqueId();
591 dtorCaller->get_statements()->push_back( dtorStmt );
592
593 // atexit(dtor_atexit);
594 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
595 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
596
597 body.push_back( new ExprStmt( noLabels, callAtexit ) );
598
599 // hoist variable and dtor caller decls to list of decls that will be added into global scope
600 staticDtorDecls.push_back( objDecl );
601 staticDtorDecls.push_back( dtorCaller );
602
603 // need to rename object uniquely since it now appears
604 // at global scope and there could be multiple function-scoped
605 // static variables with the same name in different functions.
606 // Note: it isn't sufficient to modify only the mangleName, because
607 // then subsequent Indexer passes can choke on seeing the object's name
608 // if another object has the same name and type. An unfortunate side-effect
609 // of renaming the object is that subsequent NameExprs may fail to resolve,
610 // but there shouldn't be any remaining past this point.
611 static UniqueName staticNamer( "_static_var" );
612 objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
613 objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
614
615 objDecl->set_init( NULL );
616 ctorInit->set_ctor( NULL );
617 delete ctorInit;
618
619 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
620 // create a new object which is never used
621 static UniqueName dummyNamer( "_dummy" );
622 ObjectDecl * dummy = new ObjectDecl( dummyNamer.newName(), DeclarationNode::Static, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), new VoidType( Type::Qualifiers() ) ), 0, std::list< Attribute * >{ new Attribute("unused") } );
623 return dummy;
624 }
625 } else {
626 stmtsToAddAfter.push_back( ctor );
627 } // if
628 objDecl->set_init( NULL );
629 ctorInit->set_ctor( NULL );
630 } else if ( Initializer * init = ctorInit->get_init() ) {
631 objDecl->set_init( init );
632 ctorInit->set_init( NULL );
633 } else {
634 // no constructor and no initializer, which is okay
635 objDecl->set_init( NULL );
636 } // if
637 delete ctorInit;
638 } // if
639 return objDecl;
640 }
641
642 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
643 std::set< ObjectDecl * > prevVars = curVars;
644 Parent::visit( compoundStmt );
645 curVars = prevVars;
646 }
647
648 void ObjDeclCollector::visit( DeclStmt *stmt ) {
649 // keep track of all variables currently in scope
650 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
651 curVars.insert( objDecl );
652 } // if
653 Parent::visit( stmt );
654 }
655
656 void LabelFinder::handleStmt( Statement * stmt ) {
657 // for each label, remember the variables in scope at that label.
658 for ( Label l : stmt->get_labels() ) {
659 vars[l] = curVars;
660 } // for
661 }
662
663 template<typename Iterator, typename OutputIterator>
664 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
665 for ( Iterator it = begin ; it != end ; ++it ) {
666 // extract destructor statement from the object decl and insert it into the output. Note that this is
667 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
668 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
669 // contain side effects.
670 ObjectDecl * objDecl = *it;
671 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
672 assert( ctorInit && ctorInit->get_dtor() );
673 *out++ = ctorInit->get_dtor()->clone();
674 } // for
675 }
676
677 void InsertDtors::visit( ObjectDecl * objDecl ) {
678 // remember non-static destructed objects so that their destructors can be inserted later
679 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
680 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
681 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
682 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
683 Statement * dtor = ctorInit->get_dtor();
684 if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
685 // don't need to call intrinsic dtor, because it does nothing, but
686 // non-intrinsic dtors must be called
687 reverseDeclOrder.front().push_front( objDecl );
688 } // if
689 } // if
690 } // if
691 Parent::visit( objDecl );
692 }
693
694 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
695 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
696 // when block is left, just the destructors associated with variables defined in this block, so push a new
697 // list to the top of the stack so that we can differentiate scopes
698 reverseDeclOrder.push_front( OrderedDecls() );
699 Parent::visit( compoundStmt );
700
701 // add destructors for the current scope that we're exiting
702 std::list< Statement * > & statements = compoundStmt->get_kids();
703 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
704 reverseDeclOrder.pop_front();
705 }
706
707 void InsertDtors::visit( ReturnStmt * returnStmt ) {
708 // return exits all scopes, so dump destructors for all scopes
709 for ( OrderedDecls & od : reverseDeclOrder ) {
710 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
711 } // for
712 }
713
714 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
715 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
716 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
717 // of the error. See C++ Reference 6.6 Jump Statements for details.
718 void InsertDtors::handleGoto( BranchStmt * stmt ) {
719 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
720 // S_L = lvars = set of objects in scope at label definition
721 // S_G = curVars = set of objects in scope at goto statement
722 ObjectSet & lvars = labelVars[ stmt->get_target() ];
723
724 DTOR_PRINT(
725 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
726 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
727 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
728 )
729
730 ObjectSet diff;
731 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
732 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
733 DTOR_PRINT(
734 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
735 )
736 if ( ! diff.empty() ) {
737 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
738 } // if
739 // S_G-S_L results in set of objects that must be destructed
740 diff.clear();
741 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
742 DTOR_PRINT(
743 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
744 )
745 if ( ! diff.empty() ) {
746 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
747 OrderedDecls ordered;
748 for ( OrderedDecls & rdo : reverseDeclOrder ) {
749 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
750 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
751 } // for
752 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
753 } // if
754 }
755
756 void InsertDtors::visit( BranchStmt * stmt ) {
757 switch( stmt->get_type() ) {
758 case BranchStmt::Continue:
759 case BranchStmt::Break:
760 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
761 // always be empty), but it serves as a small sanity check.
762 case BranchStmt::Goto:
763 handleGoto( stmt );
764 break;
765 default:
766 assert( false );
767 } // switch
768 }
769
770 bool checkWarnings( FunctionDecl * funcDecl ) {
771 // only check for warnings if the current function is a user-defined
772 // constructor or destructor
773 if ( ! funcDecl ) return false;
774 if ( ! funcDecl->get_statements() ) return false;
775 return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
776 }
777
778 void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
779 ValueGuard< FunctionDecl * > oldFunction( funcDecl );
780 ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
781 ValueGuard< std::set< DeclarationWithType * > > oldUsedUninit( usedUninit );
782 ValueGuard< ObjectDecl * > oldThisParam( thisParam );
783 ValueGuard< bool > oldIsCtor( isCtor );
784 ValueGuard< StructDecl * > oldStructDecl( structDecl );
785
786 // need to start with fresh sets
787 unhandled.clear();
788 usedUninit.clear();
789
790 function = funcDecl;
791 isCtor = isConstructor( function->get_name() );
792 if ( checkWarnings( function ) ) {
793 FunctionType * type = function->get_functionType();
794 assert( ! type->get_parameters().empty() );
795 thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
796 PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
797 StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
798 if ( structType ) {
799 structDecl = structType->get_baseStruct();
800 for ( Declaration * member : structDecl->get_members() ) {
801 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
802 // record all of the struct type's members that need to be constructed or
803 // destructed by the end of the function
804 unhandled.insert( field );
805 }
806 }
807 }
808 }
809 Parent::visit( function );
810
811 // remove the unhandled objects from usedUninit, because a call is inserted
812 // to handle them - only objects that are later constructed are used uninitialized.
813 std::set< DeclarationWithType * > diff;
814 std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ) );
815 for ( DeclarationWithType * member : diff ) {
816 emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", member->get_name(), " used before being constructed" );
817 }
818
819 if ( ! unhandled.empty() ) {
820 // need to explicitly re-add function parameters in order to resolve copy constructors
821 enterScope();
822 maybeAccept( function->get_functionType(), *this );
823
824 // need to iterate through members in reverse in order for
825 // ctor/dtor statements to come out in the right order
826 for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
827 DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
828 // skip non-DWT members
829 if ( ! field ) continue;
830 // skip handled members
831 if ( ! unhandled.count( field ) ) continue;
832
833 // insert and resolve default/copy constructor call for each field that's unhandled
834 std::list< Statement * > stmt;
835 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
836 deref->get_args().push_back( new VariableExpr( thisParam ) );
837
838 Expression * arg2 = 0;
839 if ( isCopyConstructor( function ) ) {
840 // if copy ctor, need to pass second-param-of-this-function.field
841 std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
842 assert( params.size() == 2 );
843 arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
844 }
845 InitExpander srcParam( arg2 );
846 SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
847
848 assert( stmt.size() <= 1 );
849 if ( stmt.size() == 1 ) {
850 Statement * callStmt = stmt.front();
851
852 MutatingResolver resolver( *this );
853 try {
854 callStmt->acceptMutator( resolver );
855 if ( isCtor ) {
856 function->get_statements()->push_front( callStmt );
857 } else {
858 // destructor statements should be added at the end
859 function->get_statements()->push_back( callStmt );
860 }
861 } catch ( SemanticError & error ) {
862 emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", field->get_name(), " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" );
863 }
864 }
865 }
866 leaveScope();
867 }
868 }
869
870 void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
871 if ( ! checkWarnings( function ) ) return;
872
873 std::string fname = getFunctionName( appExpr );
874 if ( fname == function->get_name() ) {
875 // call to same kind of function
876 Expression * firstParam = appExpr->get_args().front();
877
878 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
879 // if calling another constructor on thisParam, assume that function handles
880 // all members - if it doesn't a warning will appear in that function.
881 if ( varExpr->get_var() == thisParam ) {
882 unhandled.clear();
883 }
884 } else {
885 // if first parameter is a member expression then
886 // remove the member from unhandled set.
887 handleFirstParam( firstParam );
888 }
889 }
890
891 Parent::visit( appExpr );
892 }
893
894 void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
895 using namespace std;
896 if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
897 if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
898 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
899 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
900 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
901 if ( varExpr->get_var() == thisParam ) {
902 unhandled.erase( memberExpr->get_member() );
903 }
904 }
905 }
906 }
907 }
908 }
909 }
910
911 void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
912 if ( ! checkWarnings( function ) ) return;
913 if ( ! isCtor ) return;
914
915 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
916 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
917 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
918 if ( varExpr->get_var() == thisParam ) {
919 if ( unhandled.count( memberExpr->get_member() ) ) {
920 // emit a warning because a member was used before it was constructed
921 usedUninit.insert( memberExpr->get_member() );
922 }
923 }
924 }
925 }
926 }
927 Parent::visit( memberExpr );
928 }
929
930 template< typename Visitor, typename... Params >
931 void error( Visitor & v, const Params &... params ) {
932 v.errors.append( toString( params... ) );
933 }
934
935 template< typename... Params >
936 void GenStructMemberCalls::emit( const Params &... params ) {
937 // toggle warnings vs. errors here.
938 // warn( params... );
939 error( *this, params... );
940 }
941
942 DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
943 // add object to the indexer assumes that there will be no name collisions
944 // in generated code. If this changes, add mutate methods for entities with
945 // scope and call {enter,leave}Scope explicitly.
946 objectDecl->accept( indexer );
947 return objectDecl;
948 }
949
950 Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
951 return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
952 }
953
954 Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
955 static UniqueName tempNamer( "_tmp_ctor_expr" );
956 // xxx - is the size check necessary?
957 assert( ctorExpr->has_result() && ctorExpr->get_result()->size() == 1 );
958 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, ctorExpr->get_result()->clone(), nullptr );
959 addDeclaration( tmp );
960
961 ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
962 TypeSubstitution * env = ctorExpr->get_env();
963 ctorExpr->set_callExpr( nullptr );
964 ctorExpr->set_env( nullptr );
965
966 Expression *& firstArg = callExpr->get_args().front();
967 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
968 assign->get_args().push_back( new VariableExpr( tmp ) );
969 assign->get_args().push_back( firstArg );
970 assign->set_result( ctorExpr->get_result()->clone() );
971 firstArg = assign;
972
973 CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
974 commaExpr->set_env( env );
975 delete ctorExpr;
976 return commaExpr;
977 }
978 } // namespace
979} // namespace InitTweak
980
981// Local Variables: //
982// tab-width: 4 //
983// mode: c++ //
984// compile-command: "make install" //
985// End: //
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