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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 ab186e535e72
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 <ctype.h>
#include <assert.h>
#include <math.h>

#if __DMC__
#include <complex.h>
#endif

#include "lexer.h"
#include "mtype.h"
#include "expression.h"
#include "declaration.h"
#include "aggregate.h"
#include "init.h"


#ifdef IN_GCC
#include "d-gcc-real.h"

/* %% fix? */
extern "C" bool real_isnan (const real_t *);
#endif

static real_t zero;	// work around DMC bug for now


/*************************************
 * If expression is a variable with a const initializer,
 * return that initializer.
 */

Expression *fromConstInitializer(Expression *e1)
{
    //printf("fromConstInitializer(%s)\n", e1->toChars());
    if (e1->op == TOKvar)
    {	VarExp *ve = (VarExp *)e1;
	VarDeclaration *v = ve->var->isVarDeclaration();
	if (v && v->isConst() && v->init && !v->init->isStructInitializer())
	{   Expression *ei = v->init->toExpression();
	    if (ei && ei->type)
		e1 = ei;
	}
    }
    return e1;
}


Expression *Expression::optimize(int result)
{
    //printf("Expression::optimize(result = x%x) %s\n", result, toChars());
    return this;
}

Expression *VarExp::optimize(int result)
{
    if (result & WANTinterpret)
    {
	return fromConstInitializer(this);
    }
    return this;
}

Expression *TupleExp::optimize(int result)
{
    for (size_t i = 0; i < exps->dim; i++)
    {   Expression *e = (Expression *)exps->data[i];

	e = e->optimize(WANTvalue | (result & WANTinterpret));
	exps->data[i] = (void *)e;
    }
    return this;
}

Expression *ArrayLiteralExp::optimize(int result)
{
    if (elements)
    {
	for (size_t i = 0; i < elements->dim; i++)
	{   Expression *e = (Expression *)elements->data[i];

	    e = e->optimize(WANTvalue | (result & WANTinterpret));
	    elements->data[i] = (void *)e;
	}
    }
    return this;
}

Expression *AssocArrayLiteralExp::optimize(int result)
{
    assert(keys->dim == values->dim);
    for (size_t i = 0; i < keys->dim; i++)
    {   Expression *e = (Expression *)keys->data[i];

	e = e->optimize(WANTvalue | (result & WANTinterpret));
	keys->data[i] = (void *)e;

	e = (Expression *)values->data[i];
	e = e->optimize(WANTvalue | (result & WANTinterpret));
	values->data[i] = (void *)e;
    }
    return this;
}

Expression *StructLiteralExp::optimize(int result)
{
    if (elements)
    {
	for (size_t i = 0; i < elements->dim; i++)
	{   Expression *e = (Expression *)elements->data[i];
	    if (!e)
		continue;
	    e = e->optimize(WANTvalue | (result & WANTinterpret));
	    elements->data[i] = (void *)e;
	}
    }
    return this;
}

Expression *TypeExp::optimize(int result)
{
    return this;
}

Expression *UnaExp::optimize(int result)
{
    e1 = e1->optimize(result);
    return this;
}

Expression *NegExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    if (e1->isConst() == 1)
    {
	e = Neg(type, e1);
    }
    else
	e = this;
    return e;
}

Expression *ComExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    if (e1->isConst() == 1)
    {
	e = Com(type, e1);
    }
    else
	e = this;
    return e;
}

Expression *NotExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    if (e1->isConst() == 1)
    {
	e = Not(type, e1);
    }
    else
	e = this;
    return e;
}

Expression *BoolExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    if (e1->isConst() == 1)
    {
	e = Bool(type, e1);
    }
    else
	e = this;
    return e;
}

Expression *AddrExp::optimize(int result)
{   Expression *e;

    //printf("AddrExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(result);
    // Convert &*ex to ex
    if (e1->op == TOKstar)
    {	Expression *ex;

	ex = ((PtrExp *)e1)->e1;
	if (type->equals(ex->type))
	    e = ex;
	else
	{
	    e = ex->copy();
	    e->type = type;
	}
	return e;
    }
#if !IN_LLVM
    if (e1->op == TOKvar)
    {	VarExp *ve = (VarExp *)e1;
	if (!ve->var->isOut() && !ve->var->isRef() &&
	    !ve->var->isImportedSymbol())
	{
	    e = new SymOffExp(loc, ve->var, 0);
	    e->type = type;
	    return e;
	}
    }
    if (e1->op == TOKindex)
    {	// Convert &array[n] to &array+n
	IndexExp *ae = (IndexExp *)e1;

	if (ae->e2->op == TOKint64 && ae->e1->op == TOKvar)
	{
	    integer_t index = ae->e2->toInteger();
	    VarExp *ve = (VarExp *)ae->e1;
	    if (ve->type->ty == Tsarray && ve->type->next->ty != Tbit
		&& !ve->var->isImportedSymbol())
	    {
		TypeSArray *ts = (TypeSArray *)ve->type;
		integer_t dim = ts->dim->toInteger();
		if (index < 0 || index >= dim)
		    error("array index %jd is out of bounds [0..%jd]", index, dim);
		e = new SymOffExp(loc, ve->var, index * ts->next->size());
		e->type = type;
		return e;
	    }
	}
    }
#endif
    return this;
}

Expression *PtrExp::optimize(int result)
{
    //printf("PtrExp::optimize(result = x%x) %s\n", result, toChars());
    e1 = e1->optimize(result);
    // Convert *&ex to ex
    if (e1->op == TOKaddress)
    {	Expression *e;
	Expression *ex;

	ex = ((AddrExp *)e1)->e1;
	if (type->equals(ex->type))
	    e = ex;
	else
	{
	    e = ex->copy();
	    e->type = type;
	}
	return e;
    }
    // Constant fold *(&structliteral + offset)
    if (e1->op == TOKadd)
    {
	Expression *e;
	e = Ptr(type, e1);
	if (e != EXP_CANT_INTERPRET)
	    return e;
    }

    return this;
}

Expression *DotVarExp::optimize(int result)
{
    //printf("DotVarExp::optimize(result = x%x) %s\n", result, toChars());
    e1 = e1->optimize(result);

#if DMDV2
    if (e1->op == TOKvar)
    {	VarExp *ve = (VarExp *)e1;
	VarDeclaration *v = ve->var->isVarDeclaration();
	Expression *e = expandVar(result, v);
	if (e && e->op == TOKstructliteral)
	{   StructLiteralExp *sle = (StructLiteralExp *)e;
	    VarDeclaration *vf = var->isVarDeclaration();
	    if (vf)
	    {
		e = sle->getField(type, vf->offset);
		if (e != EXP_CANT_INTERPRET)
		    return e;
	    }
	}
    }
    else
#endif
    if (e1->op == TOKstructliteral)
    {   StructLiteralExp *sle = (StructLiteralExp *)e1;
	VarDeclaration *vf = var->isVarDeclaration();
	if (vf)
	{
	    Expression *e = sle->getField(type, vf->offset);
	    if (e != EXP_CANT_INTERPRET)
		return e;
	}
    }

    return this;
}

Expression *CallExp::optimize(int result)
{   Expression *e = this;

    e1 = e1->optimize(result);
    if (e1->op == TOKvar && result & WANTinterpret)
    {
	FuncDeclaration *fd = ((VarExp *)e1)->var->isFuncDeclaration();
	if (fd)
	{
	    Expression *eresult = fd->interpret(NULL, arguments);
	    if (eresult && eresult != EXP_VOID_INTERPRET)
		e = eresult;
	    else if (result & WANTinterpret)
		error("cannot evaluate %s at compile time", toChars());
	}
    }
    return e;
}


Expression *CastExp::optimize(int result)
{
    //printf("CastExp::optimize(result = %d) %s\n", result, toChars());
    //printf("from %s to %s\n", type->toChars(), to->toChars());
    //printf("from %s\n", type->toChars());
    //printf("e1->type %s\n", e1->type->toChars());
    //printf("type = %p\n", type);
    assert(type);
    enum TOK op1 = e1->op;

    e1 = e1->optimize(result);
    if (result & WANTinterpret)
	e1 = fromConstInitializer(e1);

    if ((e1->op == TOKstring || e1->op == TOKarrayliteral) &&
	(type->ty == Tpointer || type->ty == Tarray) &&
	type->next->equals(e1->type->next)
       )
    {
	// make a copy before adjusting type to avoid
	// messing up the type of an existing initializer
	e1 = e1->syntaxCopy();
	e1->type = type;
	return e1;
    }
    /* The first test here is to prevent infinite loops
     */
    if (op1 != TOKarrayliteral && e1->op == TOKarrayliteral)
	return e1->castTo(NULL, to);
    if (e1->op == TOKnull &&
	(type->ty == Tpointer || type->ty == Tclass))
    {
	e1->type = type;
	return e1;
    }

    if (result & WANTflags && type->ty == Tclass && e1->type->ty == Tclass)
    {
	// See if we can remove an unnecessary cast
	ClassDeclaration *cdfrom;
	ClassDeclaration *cdto;
	int offset;

	cdfrom = e1->type->isClassHandle();
	cdto   = type->isClassHandle();
	if (cdto->isBaseOf(cdfrom, &offset) && offset == 0)
	{
	    e1->type = type;
	    return e1;
	}
    }

    Expression *e;

    if (e1->isConst())
    {
	if (e1->op == TOKsymoff)
	{
	    if (type->size() == e1->type->size() &&
		type->toBasetype()->ty != Tsarray)
	    {
		e1->type = type;
		return e1;
	    }
	    return this;
	}
	if (to->toBasetype()->ty == Tvoid)
	    e = this;
	else
	    e = Cast(type, to, e1);
    }
    else
	e = this;
    return e;
}

Expression *BinExp::optimize(int result)
{
    //printf("BinExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (op == TOKshlass || op == TOKshrass || op == TOKushrass)
    {
	if (e2->isConst() == 1)
	{
	    integer_t i2 = e2->toInteger();
	    d_uns64 sz = e1->type->size() * 8;
	    if (i2 < 0 || i2 > sz)
	    {   error("shift assign by %jd is outside the range 0..%zu", i2, sz);
		e2 = new IntegerExp(0);
	    }
	}
    }
    return this;
}

Expression *AddExp::optimize(int result)
{   Expression *e;

    //printf("AddExp::optimize(%s)\n", toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() && e2->isConst())
    {
	if (e1->op == TOKsymoff && e2->op == TOKsymoff)
	    return this;
	e = Add(type, e1, e2);
    }
    else
	e = this;
    return e;
}

Expression *MinExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() && e2->isConst())
    {
	if (e2->op == TOKsymoff)
	    return this;
	e = Min(type, e1, e2);
    }
    else
	e = this;
    return e;
}

Expression *MulExp::optimize(int result)
{   Expression *e;

    //printf("MulExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
    {
	e = Mul(type, e1, e2);
    }
    else
	e = this;
    return e;
}

Expression *DivExp::optimize(int result)
{   Expression *e;

    //printf("DivExp::optimize(%s)\n", toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
    {
	e = Div(type, e1, e2);
    }
    else
	e = this;
    return e;
}

Expression *ModExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
    {
	e = Mod(type, e1, e2);
    }
    else
	e = this;
    return e;
}

Expression *shift_optimize(int result, BinExp *e, Expression *(*shift)(Type *, Expression *, Expression *))
{   Expression *ex = e;

    e->e1 = e->e1->optimize(result);
    e->e2 = e->e2->optimize(result);
    if (e->e2->isConst() == 1)
    {
	integer_t i2 = e->e2->toInteger();
	d_uns64 sz = e->e1->type->size() * 8;
	if (i2 < 0 || i2 > sz)
	{   e->error("shift by %jd is outside the range 0..%zu", i2, sz);
	    e->e2 = new IntegerExp(0);
	}
	if (e->e1->isConst() == 1)
	    ex = (*shift)(e->type, e->e1, e->e2);
    }
    return ex;
}

Expression *ShlExp::optimize(int result)
{
    //printf("ShlExp::optimize(result = %d) %s\n", result, toChars());
    return shift_optimize(result, this, Shl);
}

Expression *ShrExp::optimize(int result)
{
    //printf("ShrExp::optimize(result = %d) %s\n", result, toChars());
    return shift_optimize(result, this, Shr);
}

Expression *UshrExp::optimize(int result)
{
    //printf("UshrExp::optimize(result = %d) %s\n", result, toChars());
    return shift_optimize(result, this, Ushr);
}

Expression *AndExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
	e = And(type, e1, e2);
    else
	e = this;
    return e;
}

Expression *OrExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
	e = Or(type, e1, e2);
    else
	e = this;
    return e;
}

Expression *XorExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
	e = Xor(type, e1, e2);
    else
	e = this;
    return e;
}

Expression *CommaExp::optimize(int result)
{   Expression *e;

    //printf("CommaExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(result & WANTinterpret);
    e2 = e2->optimize(result);
    if (!e1 || e1->op == TOKint64 || e1->op == TOKfloat64 || !e1->checkSideEffect(2))
    {
	e = e2;
	if (e)
	    e->type = type;
    }
    else
	e = this;
    //printf("-CommaExp::optimize(result = %d) %s\n", result, e->toChars());
    return e;
}

Expression *ArrayLengthExp::optimize(int result)
{   Expression *e;

    //printf("ArrayLengthExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(WANTvalue | (result & WANTinterpret));
    e = this;
    if (e1->op == TOKstring || e1->op == TOKarrayliteral || e1->op == TOKassocarrayliteral)
    {
	e = ArrayLength(type, e1);
    }
    return e;
}

Expression *EqualExp::optimize(int result)
{   Expression *e;

    //printf("EqualExp::optimize(result = %x) %s\n", result, toChars());
    e1 = e1->optimize(WANTvalue | (result & WANTinterpret));
    e2 = e2->optimize(WANTvalue | (result & WANTinterpret));
    e = this;

    Expression *e1 = fromConstInitializer(this->e1);
    Expression *e2 = fromConstInitializer(this->e2);

    e = Equal(op, type, e1, e2);
    if (e == EXP_CANT_INTERPRET)
	e = this;
    return e;
}

Expression *IdentityExp::optimize(int result)
{   Expression *e;

    //printf("IdentityExp::optimize(result = %d) %s\n", result, toChars());
    e1 = e1->optimize(WANTvalue | (result & WANTinterpret));
    e2 = e2->optimize(WANTvalue | (result & WANTinterpret));
    e = this;

    if (this->e1->isConst() && this->e2->isConst())
    {
	e = Identity(op, type, this->e1, this->e2);
    }
    return e;
}

Expression *IndexExp::optimize(int result)
{   Expression *e;

    //printf("IndexExp::optimize(result = %d) %s\n", result, toChars());
    Expression *e1 = this->e1->optimize(WANTvalue | (result & WANTinterpret));
    if (result & WANTinterpret)
	e1 = fromConstInitializer(e1);
    e2 = e2->optimize(WANTvalue | (result & WANTinterpret));
    e = Index(type, e1, e2);
    if (e == EXP_CANT_INTERPRET)
	e = this;
    return e;
}

Expression *SliceExp::optimize(int result)
{   Expression *e;

    //printf("SliceExp::optimize(result = %d) %s\n", result, toChars());
    e = this;
    e1 = e1->optimize(WANTvalue | (result & WANTinterpret));
    if (!lwr)
    {	if (e1->op == TOKstring)
	{   // Convert slice of string literal into dynamic array
	    Type *t = e1->type->toBasetype();
	    if (t->next)
		e = e1->castTo(NULL, t->next->arrayOf());
	}
	return e;
    }
    if (result & WANTinterpret)
	e1 = fromConstInitializer(e1);
    lwr = lwr->optimize(WANTvalue | (result & WANTinterpret));
    upr = upr->optimize(WANTvalue | (result & WANTinterpret));
    e = Slice(type, e1, lwr, upr);
    if (e == EXP_CANT_INTERPRET)
	e = this;
    return e;
}

Expression *AndAndExp::optimize(int result)
{   Expression *e;

    //printf("AndAndExp::optimize(%d) %s\n", result, toChars());
    e1 = e1->optimize(WANTflags | (result & WANTinterpret));
    e = this;
    if (e1->isBool(FALSE))
    {
	e = new CommaExp(loc, e1, new IntegerExp(loc, 0, type));
	e->type = type;
	e = e->optimize(result);
    }
    else
    {
	e2 = e2->optimize(WANTflags | (result & WANTinterpret));
	if (result && e2->type->toBasetype()->ty == Tvoid && !global.errors)
	    error("void has no value");
	if (e1->isConst())
	{
	    if (e2->isConst())
	    {	int n1 = e1->isBool(1);
		int n2 = e2->isBool(1);

		e = new IntegerExp(loc, n1 && n2, type);
	    }
	    else if (e1->isBool(TRUE))
		e = new BoolExp(loc, e2, type);
	}
    }
    return e;
}

Expression *OrOrExp::optimize(int result)
{   Expression *e;

    e1 = e1->optimize(WANTflags | (result & WANTinterpret));
    e = this;
    if (e1->isBool(TRUE))
    {	// Replace with (e1, 1)
	e = new CommaExp(loc, e1, new IntegerExp(loc, 1, type));
	e->type = type;
	e = e->optimize(result);
    }
    else
    {
	e2 = e2->optimize(WANTflags | (result & WANTinterpret));
	if (result && e2->type->toBasetype()->ty == Tvoid && !global.errors)
	    error("void has no value");
	if (e1->isConst())
	{
	    if (e2->isConst())
	    {	int n1 = e1->isBool(1);
		int n2 = e2->isBool(1);

		e = new IntegerExp(loc, n1 || n2, type);
	    }
	    else if (e1->isBool(FALSE))
		e = new BoolExp(loc, e2, type);
	}
    }
    return e;
}

Expression *CmpExp::optimize(int result)
{   Expression *e;

    //printf("CmpExp::optimize() %s\n", toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    if (e1->isConst() == 1 && e2->isConst() == 1)
    {
	e = Cmp(op, type, this->e1, this->e2);
    }
    else
	e = this;
    return e;
}

Expression *CatExp::optimize(int result)
{   Expression *e;

    //printf("CatExp::optimize(%d) %s\n", result, toChars());
    e1 = e1->optimize(result);
    e2 = e2->optimize(result);
    e = Cat(type, e1, e2);
    if (e == EXP_CANT_INTERPRET)
	e = this;
    return e;
}


Expression *CondExp::optimize(int result)
{   Expression *e;

    econd = econd->optimize(WANTflags | (result & WANTinterpret));
    if (econd->isBool(TRUE))
	e = e1->optimize(result);
    else if (econd->isBool(FALSE))
	e = e2->optimize(result);
    else
    {	e1 = e1->optimize(result);
	e2 = e2->optimize(result);
	e = this;
    }
    return e;
}