view dmd2/init.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 356e65836fb5
children 638d16625da2
line wrap: on
line source


// Compiler implementation of the D programming language
// Copyright (c) 1999-2007 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 "mars.h"
#include "init.h"
#include "expression.h"
#include "statement.h"
#include "identifier.h"
#include "declaration.h"
#include "aggregate.h"
#include "scope.h"
#include "mtype.h"
#include "hdrgen.h"

/********************************** Initializer *******************************/

Initializer::Initializer(Loc loc)
{
    this->loc = loc;
}

Initializer *Initializer::syntaxCopy()
{
    return this;
}

Initializer *Initializer::semantic(Scope *sc, Type *t)
{
    return this;
}

Type *Initializer::inferType(Scope *sc)
{
    error(loc, "cannot infer type from initializer");
    return Type::terror;
}

Initializers *Initializer::arraySyntaxCopy(Initializers *ai)
{   Initializers *a = NULL;

    if (ai)
    {
	a = new Initializers();
	a->setDim(ai->dim);
	for (int i = 0; i < a->dim; i++)
	{   Initializer *e = (Initializer *)ai->data[i];

	    e = e->syntaxCopy();
	    a->data[i] = e;
	}
    }
    return a;
}

char *Initializer::toChars()
{   OutBuffer *buf;
    HdrGenState hgs;

    memset(&hgs, 0, sizeof(hgs));
    buf = new OutBuffer();
    toCBuffer(buf, &hgs);
    return buf->toChars();
}

/********************************** VoidInitializer ***************************/

VoidInitializer::VoidInitializer(Loc loc)
    : Initializer(loc)
{
    type = NULL;
}


Initializer *VoidInitializer::syntaxCopy()
{
    return new VoidInitializer(loc);
}


Initializer *VoidInitializer::semantic(Scope *sc, Type *t)
{
    //printf("VoidInitializer::semantic(t = %p)\n", t);
    type = t;
    return this;
}


Expression *VoidInitializer::toExpression()
{
    error(loc, "void initializer has no value");
    return new IntegerExp(0);
}


void VoidInitializer::toCBuffer(OutBuffer *buf, HdrGenState *hgs)
{
    buf->writestring("void");
}


/********************************** StructInitializer *************************/

StructInitializer::StructInitializer(Loc loc)
    : Initializer(loc)
{
    ad = NULL;
}

Initializer *StructInitializer::syntaxCopy()
{
    StructInitializer *ai = new StructInitializer(loc);

    assert(field.dim == value.dim);
    ai->field.setDim(field.dim);
    ai->value.setDim(value.dim);
    for (int i = 0; i < field.dim; i++)
    {    
	ai->field.data[i] = field.data[i];

	Initializer *init = (Initializer *)value.data[i];
	init = init->syntaxCopy();
	ai->value.data[i] = init;
    }
    return ai;
}

void StructInitializer::addInit(Identifier *field, Initializer *value)
{
    //printf("StructInitializer::addInit(field = %p, value = %p)\n", field, value);
    this->field.push(field);
    this->value.push(value);
}

Initializer *StructInitializer::semantic(Scope *sc, Type *t)
{
    TypeStruct *ts;
    int errors = 0;

    //printf("StructInitializer::semantic(t = %s) %s\n", t->toChars(), toChars());
    vars.setDim(field.dim);
    t = t->toBasetype();
    if (t->ty == Tstruct)
    {	unsigned i;
	unsigned fieldi = 0;

	ts = (TypeStruct *)t;
	ad = ts->sym;
	for (i = 0; i < field.dim; i++)
	{
	    Identifier *id = (Identifier *)field.data[i];
	    Initializer *val = (Initializer *)value.data[i];
	    Dsymbol *s;
	    VarDeclaration *v;

	    if (id == NULL)
	    {
		if (fieldi >= ad->fields.dim)
		{   error(loc, "too many initializers for %s", ad->toChars());
		    field.remove(i);
		    i--;
		    continue;
		}
		else
		{
		    s = (Dsymbol *)ad->fields.data[fieldi];
		}
	    }
	    else
	    {
		//s = ad->symtab->lookup(id);
		s = ad->search(loc, id, 0);
		if (!s)
		{
		    error(loc, "'%s' is not a member of '%s'", id->toChars(), t->toChars());
		    continue;
		}

		// Find out which field index it is
		for (fieldi = 0; 1; fieldi++)
		{
		    if (fieldi >= ad->fields.dim)
		    {
			s->error("is not a per-instance initializable field");
			break;
		    }
		    if (s == (Dsymbol *)ad->fields.data[fieldi])
			break;
		}
	    }
	    if (s && (v = s->isVarDeclaration()) != NULL)
	    {
		val = val->semantic(sc, v->type);
		value.data[i] = (void *)val;
		vars.data[i] = (void *)v;
	    }
	    else
	    {	error(loc, "%s is not a field of %s", id ? id->toChars() : s->toChars(), ad->toChars());
		errors = 1;
	    }
	    fieldi++;
	}
    }
    else if (t->ty == Tdelegate && value.dim == 0)
    {	/* Rewrite as empty delegate literal { }
	 */
	Arguments *arguments = new Arguments;
	Type *tf = new TypeFunction(arguments, NULL, 0, LINKd);
	FuncLiteralDeclaration *fd = new FuncLiteralDeclaration(loc, 0, tf, TOKdelegate, NULL);
	fd->fbody = new CompoundStatement(loc, new Statements());
	fd->endloc = loc;
	Expression *e = new FuncExp(loc, fd);
	ExpInitializer *ie = new ExpInitializer(loc, e);
	return ie->semantic(sc, t);
    }
    else
    {
	error(loc, "a struct is not a valid initializer for a %s", t->toChars());
	errors = 1;
    }
    if (errors)
    {
	field.setDim(0);
	value.setDim(0);
	vars.setDim(0);
    }
    return this;
}


/***************************************
 * This works by transforming a struct initializer into
 * a struct literal. In the future, the two should be the
 * same thing.
 */
Expression *StructInitializer::toExpression()
{   Expression *e;

    //printf("StructInitializer::toExpression() %s\n", toChars());
    if (!ad)				// if fwd referenced
    {
	return NULL;
    }
    StructDeclaration *sd = ad->isStructDeclaration();
    if (!sd)
	return NULL;
    Expressions *elements = new Expressions();
    for (size_t i = 0; i < value.dim; i++)
    {
	if (field.data[i])
	    goto Lno;
	Initializer *iz = (Initializer *)value.data[i];
	if (!iz)
	    goto Lno;
	Expression *ex = iz->toExpression();
	if (!ex)
	    goto Lno;
	elements->push(ex);
    }
    e = new StructLiteralExp(loc, sd, elements);
    e->type = sd->type;
    return e;

Lno:
    delete elements;
    //error(loc, "struct initializers as expressions are not allowed");
    return NULL;
}


void StructInitializer::toCBuffer(OutBuffer *buf, HdrGenState *hgs)
{
    //printf("StructInitializer::toCBuffer()\n");
    buf->writebyte('{');
    for (int i = 0; i < field.dim; i++)
    {
        if (i > 0)
	    buf->writebyte(',');
        Identifier *id = (Identifier *)field.data[i];
        if (id)
        {
            buf->writestring(id->toChars());
            buf->writebyte(':');
        }
        Initializer *iz = (Initializer *)value.data[i];
        if (iz)
            iz->toCBuffer(buf, hgs);
    }
    buf->writebyte('}');
}

/********************************** ArrayInitializer ************************************/

ArrayInitializer::ArrayInitializer(Loc loc)
    : Initializer(loc)
{
    dim = 0;
    type = NULL;
    sem = 0;
}

Initializer *ArrayInitializer::syntaxCopy()
{
    //printf("ArrayInitializer::syntaxCopy()\n");

    ArrayInitializer *ai = new ArrayInitializer(loc);

    assert(index.dim == value.dim);
    ai->index.setDim(index.dim);
    ai->value.setDim(value.dim);
    for (int i = 0; i < ai->value.dim; i++)
    {	Expression *e = (Expression *)index.data[i];
	if (e)
	    e = e->syntaxCopy();
	ai->index.data[i] = e;

	Initializer *init = (Initializer *)value.data[i];
	init = init->syntaxCopy();
	ai->value.data[i] = init;
    }
    return ai;
}

void ArrayInitializer::addInit(Expression *index, Initializer *value)
{
    this->index.push(index);
    this->value.push(value);
    dim = 0;
    type = NULL;
}

Initializer *ArrayInitializer::semantic(Scope *sc, Type *t)
{   unsigned i;
    unsigned length;

    //printf("ArrayInitializer::semantic(%s)\n", t->toChars());
    if (sem)				// if semantic() already run
	return this;
    sem = 1;
    type = t;
    t = t->toBasetype();
    switch (t->ty)
    {
	case Tpointer:
	case Tsarray:
	case Tarray:
	    break;

	default:
	    error(loc, "cannot use array to initialize %s", type->toChars());
	    return this;
    }

    length = 0;
    for (i = 0; i < index.dim; i++)
    {	Expression *idx;
	Initializer *val;

	idx = (Expression *)index.data[i];
	if (idx)
	{   idx = idx->semantic(sc);
	    idx = idx->optimize(WANTvalue | WANTinterpret);
	    index.data[i] = (void *)idx;
	    length = idx->toInteger();
	}

	val = (Initializer *)value.data[i];
	val = val->semantic(sc, t->nextOf());
	value.data[i] = (void *)val;
	length++;
	if (length == 0)
	    error(loc, "array dimension overflow");
	if (length > dim)
	    dim = length;
    }
    unsigned long amax = 0x80000000;
    if ((unsigned long) dim * t->nextOf()->size() >= amax)
	error(loc, "array dimension %u exceeds max of %ju", dim, amax / t->nextOf()->size());
    return this;
}

/********************************
 * If possible, convert array initializer to array literal.
 */

Expression *ArrayInitializer::toExpression()
{   Expressions *elements;
    Expression *e;

    //printf("ArrayInitializer::toExpression()\n");
    //static int i; if (++i == 2) halt();
    elements = new Expressions();
    for (size_t i = 0; i < value.dim; i++)
    {
	if (index.data[i])
	    goto Lno;
	Initializer *iz = (Initializer *)value.data[i];
	if (!iz)
	    goto Lno;
	Expression *ex = iz->toExpression();
	if (!ex)
	    goto Lno;
	elements->push(ex);
    }
    e = new ArrayLiteralExp(loc, elements);
    e->type = type;
    return e;

Lno:
    delete elements;
    error(loc, "array initializers as expressions are not allowed");
    return NULL;
}


/********************************
 * If possible, convert array initializer to associative array initializer.
 */

Initializer *ArrayInitializer::toAssocArrayInitializer()
{   Expressions *keys;
    Expressions *values;
    Expression *e;

    //printf("ArrayInitializer::toAssocArrayInitializer()\n");
    //static int i; if (++i == 2) halt();
    keys = new Expressions();
    keys->setDim(value.dim);
    values = new Expressions();
    values->setDim(value.dim);

    for (size_t i = 0; i < value.dim; i++)
    {
	e = (Expression *)index.data[i];
	if (!e)
	    goto Lno;
	keys->data[i] = (void *)e;

	Initializer *iz = (Initializer *)value.data[i];
	if (!iz)
	    goto Lno;
	e = iz->toExpression();
	if (!e)
	    goto Lno;
	values->data[i] = (void *)e;
    }
    e = new AssocArrayLiteralExp(loc, keys, values);
    return new ExpInitializer(loc, e);

Lno:
    delete keys;
    delete values;
    error(loc, "not an associative array initializer");
    return this;
}


Type *ArrayInitializer::inferType(Scope *sc)
{
    for (size_t i = 0; i < value.dim; i++)
    {
	if (index.data[i])
	    goto Lno;
    }
    if (value.dim)
    {
	Initializer *iz = (Initializer *)value.data[0];
	if (iz)
	{   Type *t = iz->inferType(sc);
	    t = new TypeSArray(t, new IntegerExp(value.dim));
	    t = t->semantic(loc, sc);
	    return t;
	}
    }

Lno:
    error(loc, "cannot infer type from this array initializer");
    return Type::terror;
}


void ArrayInitializer::toCBuffer(OutBuffer *buf, HdrGenState *hgs)
{
    buf->writebyte('[');
    for (int i = 0; i < index.dim; i++)
    {
        if (i > 0)
	    buf->writebyte(',');
        Expression *ex = (Expression *)index.data[i];
        if (ex)
        {
            ex->toCBuffer(buf, hgs);
            buf->writebyte(':');
        }
        Initializer *iz = (Initializer *)value.data[i];
        if (iz)
            iz->toCBuffer(buf, hgs);
    }
    buf->writebyte(']');
}


/********************************** ExpInitializer ************************************/

ExpInitializer::ExpInitializer(Loc loc, Expression *exp)
    : Initializer(loc)
{
    this->exp = exp;
}

Initializer *ExpInitializer::syntaxCopy()
{
    return new ExpInitializer(loc, exp->syntaxCopy());
}

Initializer *ExpInitializer::semantic(Scope *sc, Type *t)
{
    //printf("ExpInitializer::semantic(%s), type = %s\n", exp->toChars(), t->toChars());
    exp = exp->semantic(sc);
    exp = resolveProperties(sc, exp);
    exp = exp->optimize(WANTvalue | WANTinterpret);
    Type *tb = t->toBasetype();

    /* Look for case of initializing a static array with a too-short
     * string literal, such as:
     *	char[5] foo = "abc";
     * Allow this by doing an explicit cast, which will lengthen the string
     * literal.
     */
    if (exp->op == TOKstring && tb->ty == Tsarray && exp->type->ty == Tsarray)
    {	StringExp *se = (StringExp *)exp;

	if (!se->committed && se->type->ty == Tsarray &&
	    ((TypeSArray *)se->type)->dim->toInteger() <
	    ((TypeSArray *)t)->dim->toInteger())
	{
	    exp = se->castTo(sc, t);
	    goto L1;
	}
    }

    // Look for the case of statically initializing an array
    // with a single member.
    if (tb->ty == Tsarray &&
	!tb->nextOf()->equals(exp->type->toBasetype()->nextOf()) &&
	exp->implicitConvTo(tb->nextOf())
       )
    {
	t = tb->nextOf();
    }

    exp = exp->implicitCastTo(sc, t);
L1:
    exp = exp->optimize(WANTvalue | WANTinterpret);
    //printf("-ExpInitializer::semantic(): "); exp->print();
    return this;
}

Type *ExpInitializer::inferType(Scope *sc)
{
    //printf("ExpInitializer::inferType() %s\n", toChars());
    exp = exp->semantic(sc);
    exp = resolveProperties(sc, exp);

    // Give error for overloaded function addresses
    if (exp->op == TOKsymoff)
    {   SymOffExp *se = (SymOffExp *)exp;
	if (se->hasOverloads && !se->var->isFuncDeclaration()->isUnique())
	    exp->error("cannot infer type from overloaded function symbol %s", exp->toChars());
    }

    Type *t = exp->type;
    return t;
    //return t->ty == Tsarray ? t : t->toHeadMutable();
}

Expression *ExpInitializer::toExpression()
{
    return exp;
}


void ExpInitializer::toCBuffer(OutBuffer *buf, HdrGenState *hgs)
{
    exp->toCBuffer(buf, hgs);
}