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view dmd/access.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 | eeb8b95ea92e |
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// Copyright (c) 1999-2006 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 <stdlib.h> #include <assert.h> #include "root.h" #include "rmem.h" #include "enum.h" #include "aggregate.h" #include "init.h" #include "attrib.h" #include "scope.h" #include "id.h" #include "mtype.h" #include "declaration.h" #include "aggregate.h" #include "expression.h" #include "module.h" #define LOG 0 /* Code to do access checks */ int hasPackageAccess(Scope *sc, Dsymbol *s); /**************************************** * Return PROT access for Dsymbol smember in this declaration. */ enum PROT AggregateDeclaration::getAccess(Dsymbol *smember) { return PROTpublic; } enum PROT StructDeclaration::getAccess(Dsymbol *smember) { enum PROT access_ret = PROTnone; #if LOG printf("+StructDeclaration::getAccess(this = '%s', smember = '%s')\n", toChars(), smember->toChars()); #endif if (smember->toParent() == this) { access_ret = smember->prot(); } else if (smember->isDeclaration()->isStatic()) { access_ret = smember->prot(); } return access_ret; } enum PROT ClassDeclaration::getAccess(Dsymbol *smember) { enum PROT access_ret = PROTnone; #if LOG printf("+ClassDeclaration::getAccess(this = '%s', smember = '%s')\n", toChars(), smember->toChars()); #endif if (smember->toParent() == this) { access_ret = smember->prot(); } else { enum PROT access; int i; if (smember->isDeclaration()->isStatic()) { access_ret = smember->prot(); } for (i = 0; i < baseclasses.dim; i++) { BaseClass *b = (BaseClass *)baseclasses.data[i]; access = b->base->getAccess(smember); switch (access) { case PROTnone: break; case PROTprivate: access = PROTnone; // private members of base class not accessible break; case PROTpackage: case PROTprotected: case PROTpublic: case PROTexport: // If access is to be tightened if (b->protection < access) access = b->protection; // Pick path with loosest access if (access > access_ret) access_ret = access; break; default: assert(0); } } } #if LOG printf("-ClassDeclaration::getAccess(this = '%s', smember = '%s') = %d\n", toChars(), smember->toChars(), access_ret); #endif return access_ret; } /******************************************************** * Helper function for ClassDeclaration::accessCheck() * Returns: * 0 no access * 1 access */ static int accessCheckX( Dsymbol *smember, Dsymbol *sfunc, AggregateDeclaration *dthis, AggregateDeclaration *cdscope) { assert(dthis); #if 0 printf("accessCheckX for %s.%s in function %s() in scope %s\n", dthis->toChars(), smember->toChars(), sfunc ? sfunc->toChars() : "NULL", cdscope ? cdscope->toChars() : "NULL"); #endif if (dthis->hasPrivateAccess(sfunc) || dthis->isFriendOf(cdscope)) { if (smember->toParent() == dthis) return 1; else { ClassDeclaration *cdthis = dthis->isClassDeclaration(); if (cdthis) { for (int i = 0; i < cdthis->baseclasses.dim; i++) { BaseClass *b = (BaseClass *)cdthis->baseclasses.data[i]; enum PROT access; access = b->base->getAccess(smember); if (access >= PROTprotected || accessCheckX(smember, sfunc, b->base, cdscope) ) return 1; } } } } else { if (smember->toParent() != dthis) { ClassDeclaration *cdthis = dthis->isClassDeclaration(); if (cdthis) { for (int i = 0; i < cdthis->baseclasses.dim; i++) { BaseClass *b = (BaseClass *)cdthis->baseclasses.data[i]; if (accessCheckX(smember, sfunc, b->base, cdscope)) return 1; } } } } return 0; } /******************************* * Do access check for member of this class, this class being the * type of the 'this' pointer used to access smember. */ void AggregateDeclaration::accessCheck(Loc loc, Scope *sc, Dsymbol *smember) { int result; FuncDeclaration *f = sc->func; AggregateDeclaration *cdscope = sc->getStructClassScope(); enum PROT access; #if LOG printf("AggregateDeclaration::accessCheck() for %s.%s in function %s() in scope %s\n", toChars(), smember->toChars(), f ? f->toChars() : NULL, cdscope ? cdscope->toChars() : NULL); #endif Dsymbol *smemberparent = smember->toParent(); if (!smemberparent || !smemberparent->isAggregateDeclaration()) { #if LOG printf("not an aggregate member\n"); #endif return; // then it is accessible } // BUG: should enable this check //assert(smember->parent->isBaseOf(this, NULL)); if (smemberparent == this) { enum PROT access = smember->prot(); result = access >= PROTpublic || hasPrivateAccess(f) || isFriendOf(cdscope) || (access == PROTpackage && hasPackageAccess(sc, this)); #if LOG printf("result1 = %d\n", result); #endif } else if ((access = this->getAccess(smember)) >= PROTpublic) { result = 1; #if LOG printf("result2 = %d\n", result); #endif } else if (access == PROTpackage && hasPackageAccess(sc, this)) { result = 1; #if LOG printf("result3 = %d\n", result); #endif } else { result = accessCheckX(smember, f, this, cdscope); #if LOG printf("result4 = %d\n", result); #endif } if (!result) { error(loc, "member %s is not accessible", smember->toChars()); halt(); } } /**************************************** * Determine if this is the same or friend of cd. */ int AggregateDeclaration::isFriendOf(AggregateDeclaration *cd) { #if LOG printf("AggregateDeclaration::isFriendOf(this = '%s', cd = '%s')\n", toChars(), cd ? cd->toChars() : "null"); #endif if (this == cd) return 1; // Friends if both are in the same module //if (toParent() == cd->toParent()) if (cd && getModule() == cd->getModule()) { #if LOG printf("\tin same module\n"); #endif return 1; } #if LOG printf("\tnot friend\n"); #endif return 0; } /**************************************** * Determine if scope sc has package level access to s. */ int hasPackageAccess(Scope *sc, Dsymbol *s) { #if LOG printf("hasPackageAccess(s = '%s', sc = '%p')\n", s->toChars(), sc); #endif for (; s; s = s->parent) { if (s->isPackage() && !s->isModule()) break; } #if LOG if (s) printf("\tthis is in package '%s'\n", s->toChars()); #endif if (s && s == sc->module->parent) { #if LOG printf("\ts is in same package as sc\n"); #endif return 1; } #if LOG printf("\tno package access\n"); #endif return 0; } /********************************** * Determine if smember has access to private members of this declaration. */ int AggregateDeclaration::hasPrivateAccess(Dsymbol *smember) { if (smember) { AggregateDeclaration *cd = NULL; Dsymbol *smemberparent = smember->toParent(); if (smemberparent) cd = smemberparent->isAggregateDeclaration(); #if LOG printf("AggregateDeclaration::hasPrivateAccess(class %s, member %s)\n", toChars(), smember->toChars()); #endif if (this == cd) // smember is a member of this class { #if LOG printf("\tyes 1\n"); #endif return 1; // so we get private access } // If both are members of the same module, grant access while (1) { Dsymbol *sp = smember->toParent(); if (sp->isFuncDeclaration() && smember->isFuncDeclaration()) smember = sp; else break; } if (!cd && toParent() == smember->toParent()) { #if LOG printf("\tyes 2\n"); #endif return 1; } if (!cd && getModule() == smember->getModule()) { #if LOG printf("\tyes 3\n"); #endif return 1; } } #if LOG printf("\tno\n"); #endif return 0; } /**************************************** * Check access to d for expression e.d */ void accessCheck(Loc loc, Scope *sc, Expression *e, Declaration *d) { #if LOG if (e) { printf("accessCheck(%s . %s)\n", e->toChars(), d->toChars()); printf("\te->type = %s\n", e->type->toChars()); } else { //printf("accessCheck(%s)\n", d->toChars()); } #endif if (!e) { if (d->prot() == PROTprivate && d->getModule() != sc->module || d->prot() == PROTpackage && !hasPackageAccess(sc, d)) error(loc, "%s %s.%s is not accessible from %s", d->kind(), d->getModule()->toChars(), d->toChars(), sc->module->toChars()); } else if (e->type->ty == Tclass) { // Do access check ClassDeclaration *cd; cd = (ClassDeclaration *)(((TypeClass *)e->type)->sym); #if 1 if (e->op == TOKsuper) { ClassDeclaration *cd2; cd2 = sc->func->toParent()->isClassDeclaration(); if (cd2) cd = cd2; } #endif cd->accessCheck(loc, sc, d); } else if (e->type->ty == Tstruct) { // Do access check StructDeclaration *cd; cd = (StructDeclaration *)(((TypeStruct *)e->type)->sym); cd->accessCheck(loc, sc, d); } }