[PATCH 1/5] d3dcompiler: Synthesize a variable when subscripting a non-deref node.

[Matteo Bruni]

On Mon, May 4, 2020 at 10:04 PM Zebediah Figura <z.figura12 at gmail.com> wrote:
>
> Signed-off-by: Zebediah Figura <zfigura at codeweavers.com>
> ---
> There are of course other options to handle this situation, e.g. allowing
> hlsl_deref to contain either hlsl_ir_var or hlsl_ir_node, or introducing another
> deref type (e.g. HLSL_IR_DEREF and HLSL_IR_OFFSET).
>
> I'm inclined to go with this one, mostly because we don't need to handle
> multiple cases when dealing with derefs (or another case when dealing with node
> types).

First of all, sorry for the late review...

>
>  dlls/d3dcompiler_43/hlsl.y | 68 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 64 insertions(+), 4 deletions(-)
>
> diff --git a/dlls/d3dcompiler_43/hlsl.y b/dlls/d3dcompiler_43/hlsl.y
> index db305361738..01b210419c8 100644
> --- a/dlls/d3dcompiler_43/hlsl.y
> +++ b/dlls/d3dcompiler_43/hlsl.y
> @@ -125,6 +125,11 @@ static void check_invalid_matrix_modifiers(DWORD modifiers, struct source_locati
>      }
>  }
>
> +static BOOL type_is_single_reg(const struct hlsl_type *type)
> +{
> +    return type->type == HLSL_CLASS_SCALAR || type->type == HLSL_CLASS_VECTOR;

In theory there are more possible cases (e.g. matrix with suitable
dimensions and majority) although I'm not sure you want to handle
those in the same way.

> +}
> +
>  static BOOL declare_variable(struct hlsl_ir_var *decl, BOOL local)
>  {
>      BOOL ret;
> @@ -507,6 +512,41 @@ static struct hlsl_ir_jump *new_return(struct hlsl_ir_node *value, struct source
>      return jump;
>  }
>
> +static struct hlsl_ir_var *new_synthetic_var(const char *name, struct hlsl_type *type,
> +        const struct source_location loc)
> +{
> +    struct hlsl_ir_var *var;
> +
> +    if (!(var = d3dcompiler_alloc(sizeof(*var))))
> +    {
> +        hlsl_ctx.status = PARSE_ERR;
> +        return NULL;
> +    }
> +
> +    var->name = strdup(name);
> +    var->data_type = type;
> +    var->loc = loc;
> +    list_add_tail(&hlsl_ctx.globals->vars, &var->scope_entry);
> +    return var;
> +}
> +
> +static struct hlsl_ir_assignment *make_simple_assignment(struct hlsl_ir_var *lhs, struct hlsl_ir_node *rhs)
> +{
> +    struct hlsl_ir_assignment *assign;
> +
> +    if (!(assign = d3dcompiler_alloc(sizeof(*assign))))
> +        return NULL;
> +
> +    init_node(&assign->node, HLSL_IR_ASSIGNMENT, rhs->data_type, rhs->loc);
> +    assign->lhs.type = HLSL_IR_DEREF_VAR;
> +    assign->lhs.v.var = lhs;
> +    assign->rhs = rhs;
> +    if (type_is_single_reg(lhs->data_type))
> +        assign->writemask = (1 << lhs->data_type->dimx) - 1;
> +
> +    return assign;
> +}
> +
>  static struct hlsl_ir_deref *new_var_deref(struct hlsl_ir_var *var, const struct source_location loc)
>  {
>      struct hlsl_ir_deref *deref = d3dcompiler_alloc(sizeof(*deref));
> @@ -525,13 +565,33 @@ static struct hlsl_ir_deref *new_var_deref(struct hlsl_ir_var *var, const struct
>  static struct hlsl_ir_deref *new_record_deref(struct hlsl_ir_node *record,
>          struct hlsl_struct_field *field, const struct source_location loc)
>  {
> -    struct hlsl_ir_deref *deref = d3dcompiler_alloc(sizeof(*deref));
> +    struct hlsl_ir_deref *deref;
>
> -    if (!deref)
> +    if (record->type != HLSL_IR_DEREF)
>      {
> -        ERR("Out of memory.\n");
> -        return NULL;
> +        struct hlsl_ir_assignment *assign;
> +        struct hlsl_ir_var *var;
> +        char name[27];
> +
> +        sprintf(name, "<deref-%p>", record);
> +        if (!(var = new_synthetic_var(name, record->data_type, record->loc)))
> +            return NULL;
> +
> +        TRACE("Synthesized variable %p for %s node.\n", var, debug_node_type(record->type));
> +
> +        if (!(assign = make_simple_assignment(var, record)))
> +            return NULL;
> +        list_add_after(&record->entry, &assign->node.entry);
> +
> +        if (!(deref = new_var_deref(var, var->loc)))
> +            return NULL;
> +        list_add_after(&assign->node.entry, &deref->node.entry);
> +        record = &deref->node;
>      }
> +
> +    if (!(deref = d3dcompiler_alloc(sizeof(*deref))))
> +        return NULL;
> +
>      init_node(&deref->node, HLSL_IR_DEREF, field->type, loc);
>      deref->src.type = HLSL_IR_DEREF_RECORD;
>      deref->src.v.record.record = record;

This looks fine to me. It would have been nicer if we had a test
exercising this new path already in the test suite... but I don't know
that the parser currently supports any of those.