source: src/InitTweak/FixInit.cc@ b3b2077

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 stuck-waitfor-destruct with_gc
Last change on this file since b3b2077 was b3b2077, checked in by Rob Schluntz <rschlunt@…>, 10 years ago

refactor some code that generates dereference and assignment calls
  • Property mode set to 100644
File size: 42.4 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 <unordered_map>
21#include <unordered_set>
22#include "InitTweak.h"
23#include "FixInit.h"
24#include "FixGlobalInit.h"
25#include "ResolvExpr/Resolver.h"
26#include "ResolvExpr/typeops.h"
27#include "SynTree/Declaration.h"
28#include "SynTree/Type.h"
29#include "SynTree/Expression.h"
30#include "SynTree/Attribute.h"
31#include "SynTree/Statement.h"
32#include "SynTree/Initializer.h"
33#include "SynTree/Mutator.h"
34#include "SymTab/Indexer.h"
35#include "SymTab/Autogen.h"
36#include "GenPoly/PolyMutator.h"
37#include "GenPoly/DeclMutator.h"
38#include "SynTree/AddStmtVisitor.h"
39#include "CodeGen/GenType.h" // for warning/error messages
40
41bool ctordtorp = false; // print all debug
42bool ctorp = false; // print ctor debug
43bool cpctorp = false; // print copy ctor debug
44bool dtorp = false; // print dtor debug
45#define PRINT( text ) if ( ctordtorp ) { text }
46#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
47#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
48
49namespace InitTweak {
50 namespace {
51 class InsertImplicitCalls : public GenPoly::PolyMutator {
52 public:
53 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
54 /// function calls need their parameters to be copy constructed
55 static void insert( std::list< Declaration * > & translationUnit );
56
57 virtual Expression * mutate( ApplicationExpr * appExpr );
58 };
59
60 class ResolveCopyCtors : public SymTab::Indexer {
61 public:
62 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
63 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
64 /// arguments and return value temporaries
65 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
66
67 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
68
69 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
70 Expression * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
71 Expression * makeCtorDtor( const std::string & fname, Expression * thisArg, Expression * cpArg = NULL );
72 /// true if type does not need to be copy constructed to ensure correctness
73 bool skipCopyConstruct( Type * type );
74 void copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr );
75 void destructRet( Expression * ret, ImplicitCopyCtorExpr * impCpCtorExpr );
76 private:
77 TypeSubstitution * env;
78 };
79
80 /// collects constructed object decls - used as a base class
81 class ObjDeclCollector : public AddStmtVisitor {
82 public:
83 typedef AddStmtVisitor Parent;
84 using Parent::visit;
85 typedef std::set< ObjectDecl * > ObjectSet;
86 virtual void visit( CompoundStmt *compoundStmt );
87 virtual void visit( DeclStmt *stmt );
88 protected:
89 ObjectSet curVars;
90 };
91
92 // debug
93 struct printSet {
94 typedef ObjDeclCollector::ObjectSet ObjectSet;
95 printSet( const ObjectSet & objs ) : objs( objs ) {}
96 const ObjectSet & objs;
97 };
98 std::ostream & operator<<( std::ostream & out, const printSet & set) {
99 out << "{ ";
100 for ( ObjectDecl * obj : set.objs ) {
101 out << obj->get_name() << ", " ;
102 } // for
103 out << " }";
104 return out;
105 }
106
107 class LabelFinder : public ObjDeclCollector {
108 public:
109 typedef ObjDeclCollector Parent;
110 typedef std::map< Label, ObjectSet > LabelMap;
111 // map of Label -> live variables at that label
112 LabelMap vars;
113
114 void handleStmt( Statement * stmt );
115
116 // xxx - This needs to be done better.
117 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
118 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
119 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
120 // every specialized class knows about every new kind of statement that might be added.
121 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
133 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
134 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
135 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
136 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
137 };
138
139 class InsertDtors : public ObjDeclCollector {
140 public:
141 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
142 /// (currently by FixInit)
143 static void insert( std::list< Declaration * > & translationUnit );
144
145 typedef ObjDeclCollector Parent;
146 typedef std::list< ObjectDecl * > OrderedDecls;
147 typedef std::list< OrderedDecls > OrderedDeclsStack;
148
149 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
150
151 virtual void visit( ObjectDecl * objDecl );
152
153 virtual void visit( CompoundStmt * compoundStmt );
154 virtual void visit( ReturnStmt * returnStmt );
155 virtual void visit( BranchStmt * stmt );
156 private:
157 void handleGoto( BranchStmt * stmt );
158
159 LabelFinder::LabelMap & labelVars;
160 OrderedDeclsStack reverseDeclOrder;
161 };
162
163 class FixInit : public GenPoly::PolyMutator {
164 public:
165 /// expand each object declaration to use its constructor after it is declared.
166 static void fixInitializers( std::list< Declaration * > &translationUnit );
167
168 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
169
170 std::list< Declaration * > staticDtorDecls;
171 };
172
173 class FixCopyCtors : public GenPoly::PolyMutator {
174 public:
175 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
176 /// and destructors
177 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
178
179 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
180 };
181
182 class GenStructMemberCalls : public SymTab::Indexer {
183 public:
184 typedef Indexer Parent;
185 /// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
186 /// for any member that is missing a corresponding ctor/dtor call.
187 /// error if a member is used before constructed
188 static void generate( std::list< Declaration * > & translationUnit );
189
190 virtual void visit( FunctionDecl * funcDecl );
191
192 virtual void visit( MemberExpr * memberExpr );
193 virtual void visit( ApplicationExpr * appExpr );
194
195 SemanticError errors;
196 private:
197 void handleFirstParam( Expression * firstParam );
198 template< typename... Params >
199 void emit( const Params &... params );
200
201 FunctionDecl * function = 0;
202 std::set< DeclarationWithType * > unhandled, usedUninit;
203 ObjectDecl * thisParam = 0;
204 bool isCtor = false; // true if current function is a constructor
205 StructDecl * structDecl = 0;
206 };
207
208 // very simple resolver-like mutator class - used to
209 // resolve UntypedExprs that are found within newly
210 // generated constructor/destructor calls
211 class MutatingResolver : public Mutator {
212 public:
213 MutatingResolver( SymTab::Indexer & indexer ) : indexer( indexer ) {}
214
215 virtual DeclarationWithType* mutate( ObjectDecl *objectDecl );
216
217 virtual Expression* mutate( UntypedExpr *untypedExpr );
218 private:
219 SymTab::Indexer & indexer;
220 };
221
222 class FixCtorExprs : public GenPoly::DeclMutator {
223 public:
224 /// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
225 static void fix( std::list< Declaration * > & translationUnit );
226
227 virtual Expression * mutate( ConstructorExpr * ctorExpr );
228 };
229 } // namespace
230
231 void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
232 // fixes ConstructorInit for global variables. should happen before fixInitializers.
233 InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
234
235
236 InsertImplicitCalls::insert( translationUnit );
237 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
238 InsertDtors::insert( translationUnit );
239 FixInit::fixInitializers( translationUnit );
240
241 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
242 FixCopyCtors::fixCopyCtors( translationUnit );
243
244 GenStructMemberCalls::generate( translationUnit );
245 // xxx - ctor expansion currently has to be after FixCopyCtors, because there is currently a
246 // hack in the way untyped assignments are generated, where the first argument cannot have
247 // its address taken because of the way codegeneration handles UntypedExpr vs. ApplicationExpr.
248 // Thus such assignment exprs must never pushed through expression resolution (and thus should
249 // not go through the FixCopyCtors pass), otherwise they will fail -- guaranteed.
250 // Also needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
251 // don't look right, and a member can be constructed more than once.
252 FixCtorExprs::fix( translationUnit );
253 }
254
255 namespace {
256 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
257 InsertImplicitCalls inserter;
258 mutateAll( translationUnit, inserter );
259 }
260
261 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
262 ResolveCopyCtors resolver;
263 acceptAll( translationUnit, resolver );
264 }
265
266 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
267 FixInit fixer;
268
269 // can't use mutateAll, because need to insert declarations at top-level
270 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
271 SemanticError errors;
272 for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
273 try {
274 *i = maybeMutate( *i, fixer );
275 translationUnit.splice( i, fixer.staticDtorDecls );
276 } catch( SemanticError &e ) {
277 errors.append( e );
278 } // try
279 } // for
280 if ( ! errors.isEmpty() ) {
281 throw errors;
282 } // if
283 }
284
285 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
286 LabelFinder finder;
287 InsertDtors inserter( finder );
288 acceptAll( translationUnit, finder );
289 acceptAll( translationUnit, inserter );
290 }
291
292 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
293 FixCopyCtors fixer;
294 mutateAll( translationUnit, fixer );
295 }
296
297 void GenStructMemberCalls::generate( std::list< Declaration * > & translationUnit ) {
298 GenStructMemberCalls warner;
299 acceptAll( translationUnit, warner );
300
301 // visitor doesn't throw so that it can collect all errors
302 if ( ! warner.errors.isEmpty() ) {
303 throw warner.errors;
304 }
305 }
306
307 void FixCtorExprs::fix( std::list< Declaration * > & translationUnit ) {
308 FixCtorExprs fixer;
309 fixer.mutateDeclarationList( translationUnit );
310 }
311
312 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
313 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
314 assert( appExpr );
315
316 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
317 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
318 // optimization: don't need to copy construct in order to call intrinsic functions
319 return appExpr;
320 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
321 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
322 assert( ftype );
323 if ( (isConstructor( funcDecl->get_name() ) || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
324 Type * t1 = ftype->get_parameters().front()->get_type();
325 Type * t2 = ftype->get_parameters().back()->get_type();
326 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
327 assert( ptrType );
328
329 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
330 // optimization: don't need to copy construct in order to call a copy constructor or
331 // assignment operator
332 return appExpr;
333 } // if
334 } else if ( isDestructor( funcDecl->get_name() ) ) {
335 // correctness: never copy construct arguments to a destructor
336 return appExpr;
337 } // if
338 } // if
339 } // if
340 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
341
342 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
343 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
344 // save the type substitution onto the new node so that it is easy to find.
345 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
346 // The substitution is needed to obtain the type of temporary variables so that copy constructor
347 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
348 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
349 // saves the environment, or compute the types of temporaries here, but it's much simpler to
350 // save the environment here, and more cohesive to compute temporary variables and resolve copy
351 // constructor calls together.
352 assert( env );
353 expr->set_env( env );
354 return expr;
355 }
356
357 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
358 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
359 }
360
361 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
362 assert( var );
363 return makeCtorDtor( fname, new AddressExpr( new VariableExpr( var ) ), cpArg );
364 }
365
366 Expression * ResolveCopyCtors::makeCtorDtor( const std::string & fname, Expression * thisArg, Expression * cpArg ) {
367 assert( thisArg );
368 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
369 untyped->get_args().push_back( thisArg );
370 if (cpArg) untyped->get_args().push_back( cpArg->clone() );
371
372 // resolve copy constructor
373 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
374 // (VariableExpr and already resolved expression)
375 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
376 Expression * resolved = ResolvExpr::findVoidExpression( untyped, *this );
377 assert( resolved );
378 if ( resolved->get_env() ) {
379 env->add( *resolved->get_env() );
380 } // if
381
382 delete untyped;
383 return resolved;
384 }
385
386 void ResolveCopyCtors::copyConstructArg( Expression *& arg, ImplicitCopyCtorExpr * impCpCtorExpr ) {
387 static UniqueName tempNamer("_tmp_cp");
388 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
389 assert( arg->has_result() );
390 Type * result = arg->get_result();
391 if ( skipCopyConstruct( result ) ) return; // skip certain non-copyable types
392
393 // type may involve type variables, so apply type substitution to get temporary variable's actual type
394 result = result->clone();
395 impCpCtorExpr->get_env()->apply( result );
396 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
397 tmp->get_type()->set_isConst( false );
398
399 // create and resolve copy constructor
400 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
401 Expression * cpCtor = makeCtorDtor( "?{}", tmp, arg );
402
403 if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( cpCtor ) ) {
404 // if the chosen constructor is intrinsic, the copy is unnecessary, so
405 // don't create the temporary and don't call the copy constructor
406 VariableExpr * function = dynamic_cast< VariableExpr * >( appExpr->get_function() );
407 assert( function );
408 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) return;
409 }
410
411 // replace argument to function call with temporary
412 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
413 impCpCtorExpr->get_tempDecls().push_back( tmp );
414 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
415 }
416
417 void ResolveCopyCtors::destructRet( Expression * ret, ImplicitCopyCtorExpr * impCpCtorExpr ) {
418 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", new AddressExpr( ret ) ) );
419 }
420
421 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
422 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
423 Visitor::visit( impCpCtorExpr );
424 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
425
426 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
427
428 // take each argument and attempt to copy construct it.
429 for ( Expression * & arg : appExpr->get_args() ) {
430 copyConstructArg( arg, impCpCtorExpr );
431 } // for
432
433 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
434 // initialized with the return value and is destructed later
435 // xxx - handle multiple return values
436 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
437 // xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
438 // level. Trying to pass that environment along.
439 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
440 Type * result = appExpr->get_result();
441 if ( ! result->isVoid() ) {
442 static UniqueName retNamer("_tmp_cp_ret");
443 result = result->clone();
444 impCpCtorExpr->get_env()->apply( result );
445 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
446 ret->get_type()->set_isConst( false );
447 impCpCtorExpr->get_returnDecls().push_back( ret );
448 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
449 if ( ! result->get_isLvalue() ) {
450 // destructing lvalue returns is bad because it can cause multiple destructor calls to the same object - the returned object is not a temporary
451 destructRet( new VariableExpr( ret ), impCpCtorExpr );
452 }
453 } // for
454 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
455 }
456
457
458 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
459 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
460
461 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
462 assert( impCpCtorExpr );
463
464 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
465 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
466 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
467
468 // add all temporary declarations and their constructors
469 for ( ObjectDecl * obj : tempDecls ) {
470 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
471 } // for
472 for ( ObjectDecl * obj : returnDecls ) {
473 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
474 } // for
475
476 // add destructors after current statement
477 for ( Expression * dtor : dtors ) {
478 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
479 } // for
480
481 // xxx - update to work with multiple return values
482 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
483 Expression * callExpr = impCpCtorExpr->get_callExpr();
484
485 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
486
487 // detach fields from wrapper node so that it can be deleted without deleting too much
488 dtors.clear();
489 tempDecls.clear();
490 returnDecls.clear();
491 impCpCtorExpr->set_callExpr( NULL );
492 impCpCtorExpr->set_env( NULL );
493 delete impCpCtorExpr;
494
495 if ( returnDecl ) {
496 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
497 assign->get_args().push_back( new VariableExpr( returnDecl ) );
498 assign->get_args().push_back( callExpr );
499 // know the result type of the assignment is the type of the LHS (minus the pointer), so
500 // add that onto the assignment expression so that later steps have the necessary information
501 assign->set_result( returnDecl->get_type()->clone() );
502
503 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
504 if ( callExpr->get_result()->get_isLvalue() ) {
505 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
506 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
507 // type of the return temporary from T to T* to properly capture the return value. Then dereference
508 // the result of the comma expression, since the lvalue returning call was originally wrapped with
509 // an AddressExpr. Effectively, this turns
510 // lvalue T f();
511 // &*f();
512 // into
513 // T * f();
514 // T * tmp_cp_retN;
515 // &*(tmp_cp_retN = &*f(), tmp_cp_retN); // the first * and second & are generated here
516 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
517 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
518
519 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
520 retExpr->set_result( new PointerType( Type::Qualifiers(), retExpr->get_result() ) );
521 retExpr = UntypedExpr::createDeref( retExpr );
522 } // if
523 retExpr->set_env( env->clone() );
524 return retExpr;
525 } else {
526 return callExpr;
527 } // if
528 }
529
530 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
531 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
532 // is removed from the ObjectDecl
533 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
534
535 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
536 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
537 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
538 if ( Statement * ctor = ctorInit->get_ctor() ) {
539 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
540 // originally wanted to take advantage of gcc nested functions, but
541 // we get memory errors with this approach. To remedy this, the static
542 // variable is hoisted when the destructor needs to be called.
543 //
544 // generate:
545 // static T __objName_static_varN;
546 // void __objName_dtor_atexitN() {
547 // __dtor__...;
548 // }
549 // int f(...) {
550 // ...
551 // static bool __objName_uninitialized = true;
552 // if (__objName_uninitialized) {
553 // __ctor(__objName);
554 // __objName_uninitialized = false;
555 // atexit(__objName_dtor_atexitN);
556 // }
557 // ...
558 // }
559
560 static UniqueName dtorCallerNamer( "_dtor_atexit" );
561
562 // static bool __objName_uninitialized = true
563 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
564 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
565 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
566 isUninitializedVar->fixUniqueId();
567
568 // __objName_uninitialized = false;
569 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
570 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
571 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
572
573 // generate body of if
574 CompoundStmt * initStmts = new CompoundStmt( noLabels );
575 std::list< Statement * > & body = initStmts->get_kids();
576 body.push_back( ctor );
577 body.push_back( new ExprStmt( noLabels, setTrue ) );
578
579 // put it all together
580 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
581 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
582 stmtsToAddAfter.push_back( ifStmt );
583
584 if ( ctorInit->get_dtor() ) {
585 // if the object has a non-trivial destructor, have to
586 // hoist it and the object into the global space and
587 // call the destructor function with atexit.
588
589 Statement * dtorStmt = ctorInit->get_dtor()->clone();
590
591 // void __objName_dtor_atexitN(...) {...}
592 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
593 dtorCaller->fixUniqueId();
594 dtorCaller->get_statements()->push_back( dtorStmt );
595
596 // atexit(dtor_atexit);
597 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
598 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
599
600 body.push_back( new ExprStmt( noLabels, callAtexit ) );
601
602 // hoist variable and dtor caller decls to list of decls that will be added into global scope
603 staticDtorDecls.push_back( objDecl );
604 staticDtorDecls.push_back( dtorCaller );
605
606 // need to rename object uniquely since it now appears
607 // at global scope and there could be multiple function-scoped
608 // static variables with the same name in different functions.
609 // Note: it isn't sufficient to modify only the mangleName, because
610 // then subsequent Indexer passes can choke on seeing the object's name
611 // if another object has the same name and type. An unfortunate side-effect
612 // of renaming the object is that subsequent NameExprs may fail to resolve,
613 // but there shouldn't be any remaining past this point.
614 static UniqueName staticNamer( "_static_var" );
615 objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
616 objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
617
618 objDecl->set_init( NULL );
619 ctorInit->set_ctor( NULL );
620 delete ctorInit;
621
622 // xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
623 // create a new object which is never used
624 static UniqueName dummyNamer( "_dummy" );
625 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") } );
626 return dummy;
627 }
628 } else {
629 stmtsToAddAfter.push_back( ctor );
630 } // if
631 objDecl->set_init( NULL );
632 ctorInit->set_ctor( NULL );
633 } else if ( Initializer * init = ctorInit->get_init() ) {
634 objDecl->set_init( init );
635 ctorInit->set_init( NULL );
636 } else {
637 // no constructor and no initializer, which is okay
638 objDecl->set_init( NULL );
639 } // if
640 delete ctorInit;
641 } // if
642 return objDecl;
643 }
644
645 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
646 std::set< ObjectDecl * > prevVars = curVars;
647 Parent::visit( compoundStmt );
648 curVars = prevVars;
649 }
650
651 void ObjDeclCollector::visit( DeclStmt *stmt ) {
652 // keep track of all variables currently in scope
653 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
654 curVars.insert( objDecl );
655 } // if
656 Parent::visit( stmt );
657 }
658
659 void LabelFinder::handleStmt( Statement * stmt ) {
660 // for each label, remember the variables in scope at that label.
661 for ( Label l : stmt->get_labels() ) {
662 vars[l] = curVars;
663 } // for
664 }
665
666 template<typename Iterator, typename OutputIterator>
667 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
668 for ( Iterator it = begin ; it != end ; ++it ) {
669 // extract destructor statement from the object decl and insert it into the output. Note that this is
670 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
671 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
672 // contain side effects.
673 ObjectDecl * objDecl = *it;
674 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
675 assert( ctorInit && ctorInit->get_dtor() );
676 *out++ = ctorInit->get_dtor()->clone();
677 } // for
678 }
679
680 void InsertDtors::visit( ObjectDecl * objDecl ) {
681 // remember non-static destructed objects so that their destructors can be inserted later
682 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
683 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
684 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
685 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
686 Statement * dtor = ctorInit->get_dtor();
687 if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
688 // don't need to call intrinsic dtor, because it does nothing, but
689 // non-intrinsic dtors must be called
690 reverseDeclOrder.front().push_front( objDecl );
691 } // if
692 } // if
693 } // if
694 Parent::visit( objDecl );
695 }
696
697 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
698 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
699 // when block is left, just the destructors associated with variables defined in this block, so push a new
700 // list to the top of the stack so that we can differentiate scopes
701 reverseDeclOrder.push_front( OrderedDecls() );
702 Parent::visit( compoundStmt );
703
704 // add destructors for the current scope that we're exiting
705 std::list< Statement * > & statements = compoundStmt->get_kids();
706 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
707 reverseDeclOrder.pop_front();
708 }
709
710 void InsertDtors::visit( ReturnStmt * returnStmt ) {
711 // return exits all scopes, so dump destructors for all scopes
712 for ( OrderedDecls & od : reverseDeclOrder ) {
713 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
714 } // for
715 }
716
717 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
718 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
719 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
720 // of the error. See C++ Reference 6.6 Jump Statements for details.
721 void InsertDtors::handleGoto( BranchStmt * stmt ) {
722 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
723 // S_L = lvars = set of objects in scope at label definition
724 // S_G = curVars = set of objects in scope at goto statement
725 ObjectSet & lvars = labelVars[ stmt->get_target() ];
726
727 DTOR_PRINT(
728 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
729 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
730 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
731 )
732
733 ObjectSet diff;
734 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
735 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
736 DTOR_PRINT(
737 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
738 )
739 if ( ! diff.empty() ) {
740 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
741 } // if
742 // S_G-S_L results in set of objects that must be destructed
743 diff.clear();
744 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
745 DTOR_PRINT(
746 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
747 )
748 if ( ! diff.empty() ) {
749 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
750 OrderedDecls ordered;
751 for ( OrderedDecls & rdo : reverseDeclOrder ) {
752 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
753 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
754 } // for
755 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
756 } // if
757 }
758
759 void InsertDtors::visit( BranchStmt * stmt ) {
760 switch( stmt->get_type() ) {
761 case BranchStmt::Continue:
762 case BranchStmt::Break:
763 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
764 // always be empty), but it serves as a small sanity check.
765 case BranchStmt::Goto:
766 handleGoto( stmt );
767 break;
768 default:
769 assert( false );
770 } // switch
771 }
772
773 bool checkWarnings( FunctionDecl * funcDecl ) {
774 // only check for warnings if the current function is a user-defined
775 // constructor or destructor
776 if ( ! funcDecl ) return false;
777 if ( ! funcDecl->get_statements() ) return false;
778 return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
779 }
780
781 void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
782 ValueGuard< FunctionDecl * > oldFunction( funcDecl );
783 ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
784 ValueGuard< std::set< DeclarationWithType * > > oldUsedUninit( usedUninit );
785 ValueGuard< ObjectDecl * > oldThisParam( thisParam );
786 ValueGuard< bool > oldIsCtor( isCtor );
787 ValueGuard< StructDecl * > oldStructDecl( structDecl );
788
789 // need to start with fresh sets
790 unhandled.clear();
791 usedUninit.clear();
792
793 function = funcDecl;
794 isCtor = isConstructor( function->get_name() );
795 if ( checkWarnings( function ) ) {
796 FunctionType * type = function->get_functionType();
797 assert( ! type->get_parameters().empty() );
798 thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
799 PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
800 StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
801 if ( structType ) {
802 structDecl = structType->get_baseStruct();
803 for ( Declaration * member : structDecl->get_members() ) {
804 if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
805 // record all of the struct type's members that need to be constructed or
806 // destructed by the end of the function
807 unhandled.insert( field );
808 }
809 }
810 }
811 }
812 Parent::visit( function );
813
814 // remove the unhandled objects from usedUninit, because a call is inserted
815 // to handle them - only objects that are later constructed are used uninitialized.
816 std::set< DeclarationWithType * > diff;
817 std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ) );
818 for ( DeclarationWithType * member : diff ) {
819 emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", member->get_name(), " used before being constructed" );
820 }
821
822 if ( ! unhandled.empty() ) {
823 // need to explicitly re-add function parameters in order to resolve copy constructors
824 enterScope();
825 maybeAccept( function->get_functionType(), *this );
826
827 // need to iterate through members in reverse in order for
828 // ctor/dtor statements to come out in the right order
829 for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
830 DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
831 // skip non-DWT members
832 if ( ! field ) continue;
833 // skip handled members
834 if ( ! unhandled.count( field ) ) continue;
835
836 // insert and resolve default/copy constructor call for each field that's unhandled
837 std::list< Statement * > stmt;
838 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
839 deref->get_args().push_back( new VariableExpr( thisParam ) );
840
841 Expression * arg2 = 0;
842 if ( isCopyConstructor( function ) ) {
843 // if copy ctor, need to pass second-param-of-this-function.field
844 std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
845 assert( params.size() == 2 );
846 arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
847 }
848 InitExpander srcParam( arg2 );
849 SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
850
851 assert( stmt.size() <= 1 );
852 if ( stmt.size() == 1 ) {
853 Statement * callStmt = stmt.front();
854
855 MutatingResolver resolver( *this );
856 try {
857 callStmt->acceptMutator( resolver );
858 if ( isCtor ) {
859 function->get_statements()->push_front( callStmt );
860 } else {
861 // destructor statements should be added at the end
862 function->get_statements()->push_back( callStmt );
863 }
864 } catch ( SemanticError & error ) {
865 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" );
866 }
867 }
868 }
869 leaveScope();
870 }
871 }
872
873 void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
874 if ( ! checkWarnings( function ) ) return;
875
876 std::string fname = getFunctionName( appExpr );
877 if ( fname == function->get_name() ) {
878 // call to same kind of function
879 Expression * firstParam = appExpr->get_args().front();
880
881 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
882 // if calling another constructor on thisParam, assume that function handles
883 // all members - if it doesn't a warning will appear in that function.
884 if ( varExpr->get_var() == thisParam ) {
885 unhandled.clear();
886 }
887 } else {
888 // if first parameter is a member expression then
889 // remove the member from unhandled set.
890 handleFirstParam( firstParam );
891 }
892 }
893
894 Parent::visit( appExpr );
895 }
896
897 void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
898 using namespace std;
899 if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
900 if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
901 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
902 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
903 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
904 if ( varExpr->get_var() == thisParam ) {
905 unhandled.erase( memberExpr->get_member() );
906 }
907 }
908 }
909 }
910 }
911 }
912 }
913
914 void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
915 if ( ! checkWarnings( function ) ) return;
916 if ( ! isCtor ) return;
917
918 if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
919 if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
920 if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
921 if ( varExpr->get_var() == thisParam ) {
922 if ( unhandled.count( memberExpr->get_member() ) ) {
923 // emit a warning because a member was used before it was constructed
924 usedUninit.insert( memberExpr->get_member() );
925 }
926 }
927 }
928 }
929 }
930 Parent::visit( memberExpr );
931 }
932
933 template< typename Visitor, typename... Params >
934 void error( Visitor & v, const Params &... params ) {
935 v.errors.append( toString( params... ) );
936 }
937
938 template< typename... Params >
939 void GenStructMemberCalls::emit( const Params &... params ) {
940 // toggle warnings vs. errors here.
941 // warn( params... );
942 error( *this, params... );
943 }
944
945 DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
946 // add object to the indexer assumes that there will be no name collisions
947 // in generated code. If this changes, add mutate methods for entities with
948 // scope and call {enter,leave}Scope explicitly.
949 objectDecl->accept( indexer );
950 return objectDecl;
951 }
952
953 Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
954 return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
955 }
956
957 Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
958 static UniqueName tempNamer( "_tmp_ctor_expr" );
959 // xxx - is the size check necessary?
960 assert( ctorExpr->has_result() && ctorExpr->get_result()->size() == 1 );
961 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, ctorExpr->get_result()->clone(), nullptr );
962 addDeclaration( tmp );
963
964 ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
965 TypeSubstitution * env = ctorExpr->get_env();
966 ctorExpr->set_callExpr( nullptr );
967 ctorExpr->set_env( nullptr );
968
969 Expression *& firstArg = callExpr->get_args().front();
970 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
971 assign->get_args().push_back( new VariableExpr( tmp ) );
972 assign->get_args().push_back( firstArg );
973 assign->set_result( ctorExpr->get_result()->clone() );
974 firstArg = assign;
975
976 CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
977 commaExpr->set_env( env );
978 delete ctorExpr;
979 return commaExpr;
980 }
981 } // namespace
982} // namespace InitTweak
983
984// Local Variables: //
985// tab-width: 4 //
986// mode: c++ //
987// compile-command: "make install" //
988// End: //
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