gcc/d/dmd/dscope.c

   1
   2 /* Compiler implementation of the D programming language
   3  * Copyright (C) 1999-2018 by The D Language Foundation, All Rights Reserved
   4  * written by Walter Bright
   5  * http://www.digitalmars.com
   6  * Distributed under the Boost Software License, Version 1.0.
   7  * http://www.boost.org/LICENSE_1_0.txt
   8  * https://github.com/D-Programming-Language/dmd/blob/master/src/scope.c
   9  */
  10
  11 #include "root/dsystem.h"               // strlen()
  12 #include "root/root.h"
  13 #include "root/rmem.h"
  14 #include "root/speller.h"
  15
  16 #include "mars.h"
  17 #include "init.h"
  18 #include "identifier.h"
  19 #include "scope.h"
  20 #include "attrib.h"
  21 #include "dsymbol.h"
  22 #include "declaration.h"
  23 #include "statement.h"
  24 #include "aggregate.h"
  25 #include "module.h"
  26 #include "id.h"
  27 #include "template.h"
  28
  29 Scope *Scope::freelist = NULL;
  30
  31 void allocFieldinit(Scope *sc, size_t dim)
  32 {
  33     sc->fieldinit = (unsigned *)mem.xcalloc(sizeof(unsigned), dim);
  34     sc->fieldinit_dim = dim;
  35 }
  36
  37 void freeFieldinit(Scope *sc)
  38 {
  39     if (sc->fieldinit)
  40         mem.xfree(sc->fieldinit);
  41     sc->fieldinit = NULL;
  42     sc->fieldinit_dim = 0;
  43 }
  44
  45 Scope *Scope::alloc()
  46 {
  47     if (freelist)
  48     {
  49         Scope *s = freelist;
  50         freelist = s->enclosing;
  51         //printf("freelist %p\n", s);
  52         assert(s->flags & SCOPEfree);
  53         s->flags &= ~SCOPEfree;
  54         return s;
  55     }
  56
  57     return new Scope();
  58 }
  59
  60 Scope::Scope()
  61 {
  62     // Create root scope
  63
  64     //printf("Scope::Scope() %p\n", this);
  65     this->_module = NULL;
  66     this->scopesym = NULL;
  67     this->sds = NULL;
  68     this->enclosing = NULL;
  69     this->parent = NULL;
  70     this->sw = NULL;
  71     this->tf = NULL;
  72     this->os = NULL;
  73     this->tinst = NULL;
  74     this->minst = NULL;
  75     this->sbreak = NULL;
  76     this->scontinue = NULL;
  77     this->fes = NULL;
  78     this->callsc = NULL;
  79     this->aligndecl = NULL;
  80     this->func = NULL;
  81     this->slabel = NULL;
  82     this->linkage = LINKd;
  83     this->cppmangle = CPPMANGLEdefault;
  84     this->inlining = PINLINEdefault;
  85     this->protection = Prot(PROTpublic);
  86     this->explicitProtection = 0;
  87     this->stc = 0;
  88     this->depdecl = NULL;
  89     this->inunion = 0;
  90     this->nofree = 0;
  91     this->noctor = 0;
  92     this->intypeof = 0;
  93     this->lastVar = NULL;
  94     this->callSuper = 0;
  95     this->fieldinit = NULL;
  96     this->fieldinit_dim = 0;
  97     this->flags = 0;
  98     this->lastdc = NULL;
  99     this->anchorCounts = NULL;
 100     this->prevAnchor = NULL;
 101     this->userAttribDecl = NULL;
 102 }
 103
 104 Scope *Scope::copy()
 105 {
 106     Scope *sc = Scope::alloc();
 107     *sc = *this;    // memcpy
 108
 109     /* Bugzilla 11777: The copied scope should not inherit fieldinit.
 110      */
 111     sc->fieldinit = NULL;
 112
 113     return sc;
 114 }
 115
 116 Scope *Scope::createGlobal(Module *_module)
 117 {
 118     Scope *sc = Scope::alloc();
 119     *sc = Scope();  // memset
 120
 121     sc->aligndecl = NULL;
 122     sc->linkage = LINKd;
 123     sc->inlining = PINLINEdefault;
 124     sc->protection = Prot(PROTpublic);
 125
 126     sc->_module = _module;
 127
 128     sc->tinst = NULL;
 129     sc->minst = _module;
 130
 131     sc->scopesym = new ScopeDsymbol();
 132     sc->scopesym->symtab = new DsymbolTable();
 133
 134     // Add top level package as member of this global scope
 135     Dsymbol *m = _module;
 136     while (m->parent)
 137         m = m->parent;
 138     m->addMember(NULL, sc->scopesym);
 139     m->parent = NULL;                   // got changed by addMember()
 140
 141     // Create the module scope underneath the global scope
 142     sc = sc->push(_module);
 143     sc->parent = _module;
 144     return sc;
 145 }
 146
 147 Scope *Scope::push()
 148 {
 149     Scope *s = copy();
 150
 151     //printf("Scope::push(this = %p) new = %p\n", this, s);
 152     assert(!(flags & SCOPEfree));
 153     s->scopesym = NULL;
 154     s->sds = NULL;
 155     s->enclosing = this;
 156     s->slabel = NULL;
 157     s->nofree = 0;
 158     s->fieldinit = saveFieldInit();
 159     s->flags = (flags & (SCOPEcontract | SCOPEdebug | SCOPEctfe | SCOPEcompile | SCOPEconstraint |
 160                          SCOPEnoaccesscheck | SCOPEignoresymbolvisibility));
 161     s->lastdc = NULL;
 162
 163     assert(this != s);
 164     return s;
 165 }
 166
 167 Scope *Scope::push(ScopeDsymbol *ss)
 168 {
 169     //printf("Scope::push(%s)\n", ss->toChars());
 170     Scope *s = push();
 171     s->scopesym = ss;
 172     return s;
 173 }
 174
 175 Scope *Scope::pop()
 176 {
 177     //printf("Scope::pop() %p nofree = %d\n", this, nofree);
 178     Scope *enc = enclosing;
 179
 180     if (enclosing)
 181     {
 182         enclosing->callSuper |= callSuper;
 183         if (fieldinit)
 184         {
 185             if (enclosing->fieldinit)
 186             {
 187                 assert(fieldinit != enclosing->fieldinit);
 188                 size_t dim = fieldinit_dim;
 189                 for (size_t i = 0; i < dim; i++)
 190                     enclosing->fieldinit[i] |= fieldinit[i];
 191             }
 192             freeFieldinit(this);
 193         }
 194     }
 195
 196     if (!nofree)
 197     {
 198         enclosing = freelist;
 199         freelist = this;
 200         flags |= SCOPEfree;
 201     }
 202
 203     return enc;
 204 }
 205
 206 Scope *Scope::startCTFE()
 207 {
 208     Scope *sc = this->push();
 209     sc->flags = this->flags | SCOPEctfe;
 210     return sc;
 211 }
 212
 213 Scope *Scope::endCTFE()
 214 {
 215     assert(flags & SCOPEctfe);
 216     return pop();
 217 }
 218
 219 void Scope::mergeCallSuper(Loc loc, unsigned cs)
 220 {
 221     // This does a primitive flow analysis to support the restrictions
 222     // regarding when and how constructors can appear.
 223     // It merges the results of two paths.
 224     // The two paths are callSuper and cs; the result is merged into callSuper.
 225
 226     if (cs != callSuper)
 227     {
 228         // Have ALL branches called a constructor?
 229         int aAll = (cs        & (CSXthis_ctor | CSXsuper_ctor)) != 0;
 230         int bAll = (callSuper & (CSXthis_ctor | CSXsuper_ctor)) != 0;
 231
 232         // Have ANY branches called a constructor?
 233         bool aAny = (cs        & CSXany_ctor) != 0;
 234         bool bAny = (callSuper & CSXany_ctor) != 0;
 235
 236         // Have any branches returned?
 237         bool aRet = (cs        & CSXreturn) != 0;
 238         bool bRet = (callSuper & CSXreturn) != 0;
 239
 240         // Have any branches halted?
 241         bool aHalt = (cs        & CSXhalt) != 0;
 242         bool bHalt = (callSuper & CSXhalt) != 0;
 243
 244         bool ok = true;
 245
 246         if (aHalt && bHalt)
 247         {
 248             callSuper = CSXhalt;
 249         }
 250         else if ((!aHalt && aRet && !aAny && bAny) ||
 251                  (!bHalt && bRet && !bAny && aAny))
 252         {
 253             // If one has returned without a constructor call, there must be never
 254             // have been ctor calls in the other.
 255             ok = false;
 256         }
 257         else if (aHalt || (aRet && aAll))
 258         {
 259             // If one branch has called a ctor and then exited, anything the
 260             // other branch has done is OK (except returning without a
 261             // ctor call, but we already checked that).
 262             callSuper |= cs & (CSXany_ctor | CSXlabel);
 263         }
 264         else if (bHalt || (bRet && bAll))
 265         {
 266             callSuper = cs | (callSuper & (CSXany_ctor | CSXlabel));
 267         }
 268         else
 269         {
 270             // Both branches must have called ctors, or both not.
 271             ok = (aAll == bAll);
 272             // If one returned without a ctor, we must remember that
 273             // (Don't bother if we've already found an error)
 274             if (ok && aRet && !aAny)
 275                 callSuper |= CSXreturn;
 276             callSuper |= cs & (CSXany_ctor | CSXlabel);
 277         }
 278         if (!ok)
 279             error(loc, "one path skips constructor");
 280     }
 281 }
 282
 283 unsigned *Scope::saveFieldInit()
 284 {
 285     unsigned *fi = NULL;
 286     if (fieldinit)  // copy
 287     {
 288         size_t dim = fieldinit_dim;
 289         fi = (unsigned *)mem.xmalloc(sizeof(unsigned) * dim);
 290         for (size_t i = 0; i < dim; i++)
 291             fi[i] = fieldinit[i];
 292     }
 293     return fi;
 294 }
 295
 296 static bool mergeFieldInit(unsigned &fieldInit, unsigned fi, bool mustInit)
 297 {
 298     if (fi != fieldInit)
 299     {
 300         // Have any branches returned?
 301         bool aRet = (fi        & CSXreturn) != 0;
 302         bool bRet = (fieldInit & CSXreturn) != 0;
 303
 304         // Have any branches halted?
 305         bool aHalt = (fi        & CSXhalt) != 0;
 306         bool bHalt = (fieldInit & CSXhalt) != 0;
 307
 308         bool ok;
 309
 310         if (aHalt && bHalt)
 311         {
 312             ok = true;
 313             fieldInit = CSXhalt;
 314         }
 315         else if (!aHalt && aRet)
 316         {
 317             ok = !mustInit || (fi & CSXthis_ctor);
 318             fieldInit = fieldInit;
 319         }
 320         else if (!bHalt && bRet)
 321         {
 322             ok = !mustInit || (fieldInit & CSXthis_ctor);
 323             fieldInit = fi;
 324         }
 325         else if (aHalt)
 326         {
 327             ok = !mustInit || (fieldInit & CSXthis_ctor);
 328             fieldInit = fieldInit;
 329         }
 330         else if (bHalt)
 331         {
 332             ok = !mustInit || (fi & CSXthis_ctor);
 333             fieldInit = fi;
 334         }
 335         else
 336         {
 337             ok = !mustInit || !((fieldInit ^ fi) & CSXthis_ctor);
 338             fieldInit |= fi;
 339         }
 340
 341         return ok;
 342     }
 343     return true;
 344 }
 345
 346 void Scope::mergeFieldInit(Loc loc, unsigned *fies)
 347 {
 348     if (fieldinit && fies)
 349     {
 350         FuncDeclaration *f = func;
 351         if (fes) f = fes->func;
 352         AggregateDeclaration *ad = f->isMember2();
 353         assert(ad);
 354
 355         for (size_t i = 0; i < ad->fields.dim; i++)
 356         {
 357             VarDeclaration *v = ad->fields[i];
 358             bool mustInit = (v->storage_class & STCnodefaultctor ||
 359                              v->type->needsNested());
 360
 361             if (!::mergeFieldInit(fieldinit[i], fies[i], mustInit))
 362             {
 363                 ::error(loc, "one path skips field %s", ad->fields[i]->toChars());
 364             }
 365         }
 366     }
 367 }
 368
 369 Module *Scope::instantiatingModule()
 370 {
 371     // TODO: in speculative context, returning 'module' is correct?
 372     return minst ? minst : _module;
 373 }
 374
 375 static Dsymbol *searchScopes(Scope *scope, Loc loc, Identifier *ident, Dsymbol **pscopesym, int flags)
 376 {
 377     for (Scope *sc = scope; sc; sc = sc->enclosing)
 378     {
 379         assert(sc != sc->enclosing);
 380         if (!sc->scopesym)
 381             continue;
 382         //printf("\tlooking in scopesym '%s', kind = '%s', flags = x%x\n", sc->scopesym->toChars(), sc->scopesym->kind(), flags);
 383
 384         if (sc->scopesym->isModule())
 385             flags |= SearchUnqualifiedModule;        // tell Module.search() that SearchLocalsOnly is to be obeyed
 386
 387         if (Dsymbol *s = sc->scopesym->search(loc, ident, flags))
 388         {
 389             if (!(flags & (SearchImportsOnly | IgnoreErrors)) &&
 390                 ident == Id::length && sc->scopesym->isArrayScopeSymbol() &&
 391                 sc->enclosing && sc->enclosing->search(loc, ident, NULL, flags))
 392             {
 393                 warning(s->loc, "array 'length' hides other 'length' name in outer scope");
 394             }
 395             if (pscopesym)
 396                 *pscopesym = sc->scopesym;
 397             return s;
 398         }
 399         // Stop when we hit a module, but keep going if that is not just under the global scope
 400         if (sc->scopesym->isModule() && !(sc->enclosing && !sc->enclosing->enclosing))
 401             break;
 402     }
 403     return NULL;
 404 }
 405
 406 /************************************
 407  * Perform unqualified name lookup by following the chain of scopes up
 408  * until found.
 409  *
 410  * Params:
 411  *  loc = location to use for error messages
 412  *  ident = name to look up
 413  *  pscopesym = if supplied and name is found, set to scope that ident was found in
 414  *  flags = modify search based on flags
 415  *
 416  * Returns:
 417  *  symbol if found, null if not
 418  */
 419 Dsymbol *Scope::search(Loc loc, Identifier *ident, Dsymbol **pscopesym, int flags)
 420 {
 421     // This function is called only for unqualified lookup
 422     assert(!(flags & (SearchLocalsOnly | SearchImportsOnly)));
 423
 424     /* If ident is "start at module scope", only look at module scope
 425      */
 426     if (ident == Id::empty)
 427     {
 428         // Look for module scope
 429         for (Scope *sc = this; sc; sc = sc->enclosing)
 430         {
 431             assert(sc != sc->enclosing);
 432             if (!sc->scopesym)
 433                 continue;
 434
 435             if (Dsymbol *s = sc->scopesym->isModule())
 436             {
 437                 if (pscopesym)
 438                     *pscopesym = sc->scopesym;
 439                 return s;
 440             }
 441         }
 442         return NULL;
 443     }
 444
 445     if (this->flags & SCOPEignoresymbolvisibility)
 446         flags |= IgnoreSymbolVisibility;
 447
 448     Dsymbol *sold = NULL;
 449     if (global.params.bug10378 || global.params.check10378)
 450     {
 451         sold = searchScopes(this, loc, ident, pscopesym, flags | IgnoreSymbolVisibility);
 452         if (!global.params.check10378)
 453             return sold;
 454
 455         if (ident == Id::dollar) // Bugzilla 15825
 456             return sold;
 457
 458         // Search both ways
 459     }
 460
 461     // First look in local scopes
 462     Dsymbol *s = searchScopes(this, loc, ident, pscopesym, flags | SearchLocalsOnly);
 463     if (!s)
 464     {
 465         // Second look in imported modules
 466         s = searchScopes(this, loc, ident, pscopesym, flags | SearchImportsOnly);
 467         /** Still find private symbols, so that symbols that weren't access
 468          * checked by the compiler remain usable.  Once the deprecation is over,
 469          * this should be moved to search_correct instead.
 470          */
 471         if (!s && !(flags & IgnoreSymbolVisibility))
 472         {
 473             s = searchScopes(this, loc, ident, pscopesym, flags | SearchLocalsOnly | IgnoreSymbolVisibility);
 474             if (!s)
 475                 s = searchScopes(this, loc, ident, pscopesym, flags | SearchImportsOnly | IgnoreSymbolVisibility);
 476
 477             if (s && !(flags & IgnoreErrors))
 478                 ::deprecation(loc, "%s is not visible from module %s", s->toPrettyChars(), _module->toChars());
 479         }
 480     }
 481
 482     if (global.params.check10378)
 483     {
 484         Dsymbol *snew = s;
 485         if (sold != snew)
 486             deprecation10378(loc, sold, snew);
 487         if (global.params.bug10378)
 488             s = sold;
 489     }
 490     return s;
 491 }
 492
 493 Dsymbol *Scope::insert(Dsymbol *s)
 494 {
 495     if (VarDeclaration *vd = s->isVarDeclaration())
 496     {
 497         if (lastVar)
 498             vd->lastVar = lastVar;
 499         lastVar = vd;
 500     }
 501     else if (WithScopeSymbol *ss = s->isWithScopeSymbol())
 502     {
 503         if (VarDeclaration *vd = ss->withstate->wthis)
 504         {
 505             if (lastVar)
 506                 vd->lastVar = lastVar;
 507             lastVar = vd;
 508         }
 509         return NULL;
 510     }
 511     for (Scope *sc = this; sc; sc = sc->enclosing)
 512     {
 513         //printf("\tsc = %p\n", sc);
 514         if (sc->scopesym)
 515         {
 516             //printf("\t\tsc->scopesym = %p\n", sc->scopesym);
 517             if (!sc->scopesym->symtab)
 518                 sc->scopesym->symtab = new DsymbolTable();
 519             return sc->scopesym->symtabInsert(s);
 520         }
 521     }
 522     assert(0);
 523     return NULL;
 524 }
 525
 526 /********************************************
 527  * Search enclosing scopes for ClassDeclaration.
 528  */
 529
 530 ClassDeclaration *Scope::getClassScope()
 531 {
 532     for (Scope *sc = this; sc; sc = sc->enclosing)
 533     {
 534         if (!sc->scopesym)
 535             continue;
 536
 537         ClassDeclaration *cd = sc->scopesym->isClassDeclaration();
 538         if (cd)
 539             return cd;
 540     }
 541     return NULL;
 542 }
 543
 544 /********************************************
 545  * Search enclosing scopes for ClassDeclaration.
 546  */
 547
 548 AggregateDeclaration *Scope::getStructClassScope()
 549 {
 550     for (Scope *sc = this; sc; sc = sc->enclosing)
 551     {
 552         if (!sc->scopesym)
 553             continue;
 554
 555         AggregateDeclaration *ad = sc->scopesym->isClassDeclaration();
 556         if (ad)
 557             return ad;
 558         ad = sc->scopesym->isStructDeclaration();
 559         if (ad)
 560             return ad;
 561     }
 562     return NULL;
 563 }
 564
 565 /*******************************************
 566  * For TemplateDeclarations, we need to remember the Scope
 567  * where it was declared. So mark the Scope as not
 568  * to be free'd.
 569  */
 570
 571 void Scope::setNoFree()
 572 {
 573     //int i = 0;
 574
 575     //printf("Scope::setNoFree(this = %p)\n", this);
 576     for (Scope *sc = this; sc; sc = sc->enclosing)
 577     {
 578         //printf("\tsc = %p\n", sc);
 579         sc->nofree = 1;
 580
 581         assert(!(flags & SCOPEfree));
 582         //assert(sc != sc->enclosing);
 583         //assert(!sc->enclosing || sc != sc->enclosing->enclosing);
 584         //if (++i == 10)
 585             //assert(0);
 586     }
 587 }
 588
 589 structalign_t Scope::alignment()
 590 {
 591     if (aligndecl)
 592         return aligndecl->getAlignment(this);
 593     else
 594         return STRUCTALIGN_DEFAULT;
 595 }
 596
 597 /************************************************
 598  * Given the failed search attempt, try to find
 599  * one with a close spelling.
 600  */
 601
 602 void *scope_search_fp(void *arg, const char *seed, int* cost)
 603 {
 604     //printf("scope_search_fp('%s')\n", seed);
 605
 606     /* If not in the lexer's string table, it certainly isn't in the symbol table.
 607      * Doing this first is a lot faster.
 608      */
 609     size_t len = strlen(seed);
 610     if (!len)
 611         return NULL;
 612     Identifier *id = Identifier::lookup(seed, len);
 613     if (!id)
 614         return NULL;
 615
 616     Scope *sc = (Scope *)arg;
 617     Module::clearCache();
 618     Dsymbol *scopesym = NULL;
 619     Dsymbol *s = sc->search(Loc(), id, &scopesym, IgnoreErrors);
 620     if (s)
 621     {
 622         for (*cost = 0; sc; sc = sc->enclosing, (*cost)++)
 623             if (sc->scopesym == scopesym)
 624                 break;
 625         if (scopesym != s->parent)
 626         {
 627             (*cost)++; // got to the symbol through an import
 628             if (s->prot().kind == PROTprivate)
 629                 return NULL;
 630         }
 631     }
 632     return (void*)s;
 633 }
 634
 635 void Scope::deprecation10378(Loc loc, Dsymbol *sold, Dsymbol *snew)
 636 {
 637     // Bugzilla 15857
 638     //
 639     // The overloadset found via the new lookup rules is either
 640     // equal or a subset of the overloadset found via the old
 641     // lookup rules, so it suffices to compare the dimension to
 642     // check for equality.
 643     OverloadSet *osold = NULL;
 644     OverloadSet *osnew = NULL;
 645     if (sold && (osold = sold->isOverloadSet()) != NULL &&
 646         snew && (osnew = snew->isOverloadSet()) != NULL &&
 647         osold->a.dim == osnew->a.dim)
 648         return;
 649
 650     OutBuffer buf;
 651     buf.writestring("local import search method found ");
 652     if (osold)
 653         buf.printf("%s %s (%d overloads)", sold->kind(), sold->toPrettyChars(), (int)osold->a.dim);
 654     else if (sold)
 655         buf.printf("%s %s", sold->kind(), sold->toPrettyChars());
 656     else
 657         buf.writestring("nothing");
 658     buf.writestring(" instead of ");
 659     if (osnew)
 660         buf.printf("%s %s (%d overloads)", snew->kind(), snew->toPrettyChars(), (int)osnew->a.dim);
 661     else if (snew)
 662         buf.printf("%s %s", snew->kind(), snew->toPrettyChars());
 663     else
 664         buf.writestring("nothing");
 665
 666     deprecation(loc, "%s", buf.peekString());
 667 }
 668
 669 Dsymbol *Scope::search_correct(Identifier *ident)
 670 {
 671     if (global.gag)
 672         return NULL;            // don't do it for speculative compiles; too time consuming
 673
 674     return (Dsymbol *)speller(ident->toChars(), &scope_search_fp, this, idchars);
 675 }
 676
 677 /************************************
 678  * Maybe `ident` was a C or C++ name. Check for that,
 679  * and suggest the D equivalent.
 680  * Params:
 681  *  ident = unknown identifier
 682  * Returns:
 683  *  D identifier string if found, null if not
 684  */
 685 const char *Scope::search_correct_C(Identifier *ident)
 686 {
 687     TOK tok;
 688     if (ident == Id::_NULL)
 689         tok = TOKnull;
 690     else if (ident == Id::_TRUE)
 691         tok = TOKtrue;
 692     else if (ident == Id::_FALSE)
 693         tok = TOKfalse;
 694     else if (ident == Id::_unsigned)
 695         tok = TOKuns32;
 696     else
 697         return NULL;
 698     return Token::toChars(tok);
 699 }