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view dmd/scope.c @ 1117:4c20fcc4252b
Fun with parameter attributes: For several of the "synthetic" parameters added
to D functions, we can apply noalias and nocapture. They are sret parameters,
'nest' pointers passed to nested functions, and _argptr:
Nocapture:
- Sret and nest are nocapture because they don't represent D-level variables,
and thus the callee can't (validly) obtain a pointer to them, let alone keep
it around after it returns.
- _argptr is nocapture because although the callee has access to it as a
pointer, that pointer is invalidated when it returns.
All three are noalias because they're function-local variables
- Sret and _argptr are noalias because they're freshly alloca'd memory only
used for a single function call that's not allowed to keep an aliasing
pointer to it around (since the parameter is nocapture).
- 'Nest' is noalias because the callee only ever has access to one such pointer
per parent function, and every parent function has a different one.
This commit also ensures attributes set on sret, _arguments and _argptr are
propagated to calls to such functions.
It also adds one exception to the general rule that attributes on function types
should propagate to calls: the type of a delegate's function pointer has a
'nest' parameter, but this can either be a true 'nest' (for delegates to nested
functions) or a 'this' (for delegates to member functions). Since 'this' is
neither noalias nor nocapture, and there's generally no way to tell which one it
is, we remove these attributes at the call site if the callee is a delegate.
author | Frits van Bommel <fvbommel wxs.nl> |
---|---|
date | Sat, 14 Mar 2009 22:15:31 +0100 |
parents | b30fe7e1dbb9 |
children | f99a3b393c03 |
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// Copyright (c) 1999-2005 by Digital Mars // All Rights Reserved // written by Walter Bright // http://www.digitalmars.com // License for redistribution is by either the Artistic License // in artistic.txt, or the GNU General Public License in gnu.txt. // See the included readme.txt for details. #include <stdio.h> #include <assert.h> #include "root.h" #include "mars.h" #include "init.h" #include "identifier.h" #include "attrib.h" #include "dsymbol.h" #include "scope.h" #include "declaration.h" #include "aggregate.h" #include "module.h" #include "id.h" Scope *Scope::freelist = NULL; void *Scope::operator new(size_t size) { if (freelist) { Scope *s = freelist; freelist = s->enclosing; //printf("freelist %p\n", s); assert(s->flags & SCOPEfree); s->flags &= ~SCOPEfree; return s; } void *p = ::operator new(size); //printf("new %p\n", p); return p; } Scope::Scope() { // Create root scope //printf("Scope::Scope() %p\n", this); this->module = NULL; this->scopesym = NULL; this->sd = NULL; this->enclosing = NULL; this->parent = NULL; this->sw = NULL; this->tf = NULL; this->tfOfTry = NULL; this->tinst = NULL; this->sbreak = NULL; this->scontinue = NULL; this->fes = NULL; this->structalign = global.structalign; this->func = NULL; this->slabel = NULL; this->linkage = LINKd; this->protection = PROTpublic; this->explicitProtection = 0; this->stc = 0; this->offset = 0; this->inunion = 0; this->incontract = 0; this->nofree = 0; this->noctor = 0; this->noaccesscheck = 0; this->intypeof = 0; this->parameterSpecialization = 0; this->callSuper = 0; this->flags = 0; this->anonAgg = NULL; this->lastdc = NULL; this->lastoffset = 0; this->docbuf = NULL; } Scope::Scope(Scope *enclosing) { //printf("Scope::Scope(enclosing = %p) %p\n", enclosing, this); assert(!(enclosing->flags & SCOPEfree)); this->module = enclosing->module; this->func = enclosing->func; this->parent = enclosing->parent; this->scopesym = NULL; this->sd = NULL; this->sw = enclosing->sw; this->tf = enclosing->tf; this->tfOfTry = enclosing->tfOfTry; this->tinst = enclosing->tinst; this->sbreak = enclosing->sbreak; this->scontinue = enclosing->scontinue; this->fes = enclosing->fes; this->structalign = enclosing->structalign; this->enclosing = enclosing; #ifdef DEBUG if (enclosing->enclosing) assert(!(enclosing->enclosing->flags & SCOPEfree)); if (this == enclosing->enclosing) { printf("this = %p, enclosing = %p, enclosing->enclosing = %p\n", this, enclosing, enclosing->enclosing); } assert(this != enclosing->enclosing); #endif this->slabel = NULL; this->linkage = enclosing->linkage; this->protection = enclosing->protection; this->explicitProtection = enclosing->explicitProtection; this->stc = enclosing->stc; this->offset = 0; this->inunion = enclosing->inunion; this->incontract = enclosing->incontract; this->nofree = 0; this->noctor = enclosing->noctor; this->noaccesscheck = enclosing->noaccesscheck; this->intypeof = enclosing->intypeof; this->parameterSpecialization = enclosing->parameterSpecialization; this->callSuper = enclosing->callSuper; this->flags = 0; this->anonAgg = NULL; this->lastdc = NULL; this->lastoffset = 0; this->docbuf = enclosing->docbuf; assert(this != enclosing); } Scope *Scope::createGlobal(Module *module) { Scope *sc; sc = new Scope(); sc->module = module; sc->scopesym = new ScopeDsymbol(); sc->scopesym->symtab = new DsymbolTable(); // Add top level package as member of this global scope Dsymbol *m = module; while (m->parent) m = m->parent; m->addMember(NULL, sc->scopesym, 1); m->parent = NULL; // got changed by addMember() // Create the module scope underneath the global scope sc = sc->push(module); sc->parent = module; return sc; } Scope *Scope::push() { //printf("Scope::push()\n"); Scope *s = new Scope(this); assert(this != s); return s; } Scope *Scope::push(ScopeDsymbol *ss) { //printf("Scope::push(%s)\n", ss->toChars()); Scope *s = push(); s->scopesym = ss; return s; } Scope *Scope::pop() { //printf("Scope::pop() %p nofree = %d\n", this, nofree); Scope *enc = enclosing; if (enclosing) enclosing->callSuper |= callSuper; if (!nofree) { enclosing = freelist; freelist = this; flags |= SCOPEfree; } return enc; } void Scope::mergeCallSuper(Loc loc, unsigned cs) { // This does a primitive flow analysis to support the restrictions // regarding when and how constructors can appear. // It merges the results of two paths. // The two paths are callSuper and cs; the result is merged into callSuper. if (cs != callSuper) { int a; int b; callSuper |= cs & (CSXany_ctor | CSXlabel); if (cs & CSXreturn) { } else if (callSuper & CSXreturn) { callSuper = cs | (callSuper & (CSXany_ctor | CSXlabel)); } else { a = (cs & (CSXthis_ctor | CSXsuper_ctor)) != 0; b = (callSuper & (CSXthis_ctor | CSXsuper_ctor)) != 0; if (a != b) error(loc, "one path skips constructor"); callSuper |= cs; } } } Dsymbol *Scope::search(Loc loc, Identifier *ident, Dsymbol **pscopesym) { Dsymbol *s; Scope *sc; //printf("Scope::search(%p, '%s')\n", this, ident->toChars()); if (ident == Id::empty) { // Look for module scope for (sc = this; sc; sc = sc->enclosing) { assert(sc != sc->enclosing); if (sc->scopesym) { s = sc->scopesym->isModule(); if (s) { //printf("\tfound %s.%s\n", s->parent ? s->parent->toChars() : "", s->toChars()); if (pscopesym) *pscopesym = sc->scopesym; return s; } } } return NULL; } for (sc = this; sc; sc = sc->enclosing) { assert(sc != sc->enclosing); if (sc->scopesym) { //printf("\tlooking in scopesym '%s', kind = '%s'\n", sc->scopesym->toChars(), sc->scopesym->kind()); s = sc->scopesym->search(loc, ident, 0); if (s) { if ((global.params.warnings || global.params.Dversion > 1) && ident == Id::length && sc->scopesym->isArrayScopeSymbol() && sc->enclosing && sc->enclosing->search(loc, ident, NULL)) { warning(s->loc, "array 'length' hides other 'length' name in outer scope"); } //printf("\tfound %s.%s, kind = '%s'\n", s->parent ? s->parent->toChars() : "", s->toChars(), s->kind()); if (pscopesym) *pscopesym = sc->scopesym; return s; } } } return NULL; } Dsymbol *Scope::insert(Dsymbol *s) { Scope *sc; for (sc = this; sc; sc = sc->enclosing) { //printf("\tsc = %p\n", sc); if (sc->scopesym) { //printf("\t\tsc->scopesym = %p\n", sc->scopesym); if (!sc->scopesym->symtab) sc->scopesym->symtab = new DsymbolTable(); return sc->scopesym->symtab->insert(s); } } assert(0); return NULL; } /******************************************** * Search enclosing scopes for ClassDeclaration. */ ClassDeclaration *Scope::getClassScope() { Scope *sc; for (sc = this; sc; sc = sc->enclosing) { ClassDeclaration *cd; if (sc->scopesym) { cd = sc->scopesym->isClassDeclaration(); if (cd) return cd; } } return NULL; } /******************************************** * Search enclosing scopes for ClassDeclaration. */ AggregateDeclaration *Scope::getStructClassScope() { Scope *sc; for (sc = this; sc; sc = sc->enclosing) { AggregateDeclaration *ad; if (sc->scopesym) { ad = sc->scopesym->isClassDeclaration(); if (ad) return ad; else { ad = sc->scopesym->isStructDeclaration(); if (ad) return ad; } } } return NULL; } /******************************************* * For TemplateDeclarations, we need to remember the Scope * where it was declared. So mark the Scope as not * to be free'd. */ void Scope::setNoFree() { Scope *sc; //int i = 0; //printf("Scope::setNoFree(this = %p)\n", this); for (sc = this; sc; sc = sc->enclosing) { //printf("\tsc = %p\n", sc); sc->nofree = 1; assert(!(flags & SCOPEfree)); //assert(sc != sc->enclosing); //assert(!sc->enclosing || sc != sc->enclosing->enclosing); //if (++i == 10) //assert(0); } }