view dmd2/scope.h @ 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 356e65836fb5
children 638d16625da2
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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.

#ifndef DMD_SCOPE_H
#define DMD_SCOPE_H

#ifdef __DMC__
#pragma once
#endif /* __DMC__ */

struct Dsymbol;
struct ScopeDsymbol;
struct Array;
struct Identifier;
struct Module;
struct Statement;
struct SwitchStatement;
struct TryFinallyStatement;
struct LabelStatement;
struct ForeachStatement;
struct ClassDeclaration;
struct AggregateDeclaration;
struct AnonymousAggregateDeclaration;
struct FuncDeclaration;
struct DocComment;
struct EnclosingHandler;
struct AnonDeclaration;
#if __GNUC__
#include "dsymbol.h"    // PROT
#include "mars.h"       // LINK
#else
enum LINK;
enum PROT;
#endif 

struct Scope
{
    Scope *enclosing;		// enclosing Scope

    Module *module;		// Root module
    ScopeDsymbol *scopesym;	// current symbol
    ScopeDsymbol *sd;		// if in static if, and declaring new symbols,
				// sd gets the addMember()
    FuncDeclaration *func;	// function we are in
    Dsymbol *parent;		// parent to use
    LabelStatement *slabel;	// enclosing labelled statement
    SwitchStatement *sw;	// enclosing switch statement
    TryFinallyStatement *tf;	// enclosing try finally statement; set inside its finally block
    EnclosingHandler *tfOfTry; // enclosing try-finally, volatile or synchronized statement; set inside its try or body block
    TemplateInstance *tinst;	// enclosing template instance
    Statement *sbreak;		// enclosing statement that supports "break"
    Statement *scontinue;	// enclosing statement that supports "continue"
    ForeachStatement *fes;	// if nested function for ForeachStatement, this is it
    unsigned offset;		// next offset to use in aggregate
    int inunion;		// we're processing members of a union
    int incontract;		// we're inside contract code
    int nofree;			// set if shouldn't free it
    int noctor;			// set if constructor calls aren't allowed
    int intypeof;		// in typeof(exp)
    int parameterSpecialization; // if in template parameter specialization
    int noaccesscheck;		// don't do access checks

    unsigned callSuper;		// primitive flow analysis for constructors
#define	CSXthis_ctor	1	// called this()
#define CSXsuper_ctor	2	// called super()
#define CSXthis		4	// referenced this
#define CSXsuper	8	// referenced super
#define CSXlabel	0x10	// seen a label
#define CSXreturn	0x20	// seen a return statement
#define CSXany_ctor	0x40	// either this() or super() was called

    unsigned structalign;	// alignment for struct members
    enum LINK linkage;		// linkage for external functions

    enum PROT protection;	// protection for class members
    int explicitProtection;	// set if in an explicit protection attribute

    unsigned stc;		// storage class

    unsigned flags;
#define SCOPEctor	1	// constructor type
#define SCOPEstaticif	2	// inside static if
#define SCOPEfree	4	// is on free list

    AnonymousAggregateDeclaration *anonAgg;	// for temporary analysis

    DocComment *lastdc;		// documentation comment for last symbol at this scope
    unsigned lastoffset;	// offset in docbuf of where to insert next dec
    OutBuffer *docbuf;		// buffer for documentation output

    static Scope *freelist;
    static void *operator new(size_t sz);
    static Scope *createGlobal(Module *module);

    Scope();
    Scope(Module *module);
    Scope(Scope *enclosing);

    Scope *push();
    Scope *push(ScopeDsymbol *ss);
    Scope *pop();

    void mergeCallSuper(Loc loc, unsigned cs);

    Dsymbol *search(Loc loc, Identifier *ident, Dsymbol **pscopesym);
    Dsymbol *insert(Dsymbol *s);

    ClassDeclaration *getClassScope();
    AggregateDeclaration *getStructClassScope();
    void setNoFree();
};

#endif /* DMD_SCOPE_H */