On 4 September 2013 15:22, Kenneth Graunke <kenn...@whitecape.org> wrote:
> For the upcoming built-in function rewrite, we'll need to be able to
> answer "Is this built-in function signature available?".
>
> This is actually a somewhat complex question, since it depends on the
> language version, GLSL vs. GLSL ES, enabled extensions, and the current
> shader stage.
>
> Storing such a set of constraints in a structure would be painful, so
> instead we store a function pointer. When creating a signature, we
> simply point to a predicate that inspects _mesa_glsl_parse_state and
> answers whether the signature is available in the current shader.
>
> Unfortunately, IR reader doesn't actually know when built-in functions
> are available, so this patch makes it lie and say that they're always
> present. This allows us to hook up the new functionality; it just won't
> be useful until real data is populated. In the meantime, the existing
> profile mechanism ensures built-ins are available in the right places.
>
> Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
> ---
> src/glsl/ir.cpp | 8 +++++---
> src/glsl/ir.h | 14 +++++++++++++-
> src/glsl/ir_clone.cpp | 1 +
> src/glsl/ir_reader.cpp | 13 +++++++++++--
> 4 files changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
> index c6d96d8..ea018eb 100644
> --- a/src/glsl/ir.cpp
> +++ b/src/glsl/ir.cpp
> @@ -1579,11 +1579,13 @@ ir_variable::determine_interpolation_mode(bool
> flat_shade)
> }
>
>
> -ir_function_signature::ir_function_signature(const glsl_type *return_type)
> - : return_type(return_type), is_defined(false), _function(NULL)
> +ir_function_signature::ir_function_signature(const glsl_type *return_type,
> + builtin_available_predicate
> b)
> + : return_type(return_type), is_defined(false), builtin_info(b),
> + _function(NULL)
> {
> this->ir_type = ir_type_function_signature;
> - this->is_builtin = false;
> + this->is_builtin = builtin_info != NULL;
> this->origin = NULL;
> }
>
> diff --git a/src/glsl/ir.h b/src/glsl/ir.h
> index b45e6cb..d785259 100644
> --- a/src/glsl/ir.h
> +++ b/src/glsl/ir.h
> @@ -591,6 +591,11 @@ public:
> const glsl_type *interface_type;
> };
>
> +/**
> + * A function that returns whether a built-in function is available in the
> + * current shading language (based on version, ES or desktop, and
> extensions).
> + */
> +typedef bool (*builtin_available_predicate)(const _mesa_glsl_parse_state
> *);
>
> /*@{*/
> /**
> @@ -602,7 +607,8 @@ class ir_function_signature : public ir_instruction {
> * an ir_function.
> */
> public:
> - ir_function_signature(const glsl_type *return_type);
> + ir_function_signature(const glsl_type *return_type,
> + builtin_available_predicate builtin_info = NULL);
>
> virtual ir_function_signature *clone(void *mem_ctx,
> struct hash_table *ht) const;
> @@ -684,6 +690,12 @@ public:
> struct exec_list body;
>
> private:
> + /**
> + * A function pointer to a predicate that answers whether a built-in
> + * function is available in the current shader. NULL if not a
> built-in.
> + */
> + builtin_available_predicate builtin_info;
> +
>
I'd prefer to see this called something like "builtin_avail" instead of
"builtin_info" since that describes precisely what info it's storing about
the function. Calling it "builtin_info" makes it sound like it stores a
variety of information about built-in functions.
It's a nit-pick, though, so either way, this patch is:
Reviewed-by: Paul Berry <stereotype...@gmail.com>
> /** Function of which this signature is one overload. */
> class ir_function *_function;
>
> diff --git a/src/glsl/ir_clone.cpp b/src/glsl/ir_clone.cpp
> index 9d4178d..967ad70 100644
> --- a/src/glsl/ir_clone.cpp
> +++ b/src/glsl/ir_clone.cpp
> @@ -328,6 +328,7 @@ ir_function_signature::clone_prototype(void *mem_ctx,
> struct hash_table *ht) con
>
> copy->is_defined = false;
> copy->is_builtin = this->is_builtin;
> + copy->builtin_info = this->builtin_info;
> copy->origin = this;
>
> /* Clone the parameter list, but NOT the body.
> diff --git a/src/glsl/ir_reader.cpp b/src/glsl/ir_reader.cpp
> index f263fe8..8261d9f 100644
> --- a/src/glsl/ir_reader.cpp
> +++ b/src/glsl/ir_reader.cpp
> @@ -211,6 +211,12 @@ ir_reader::read_function(s_expression *expr, bool
> skip_body)
> return added ? f : NULL;
> }
>
> +static bool
> +always_available(const _mesa_glsl_parse_state *)
> +{
> + return true;
> +}
> +
> void
> ir_reader::read_function_sig(ir_function *f, s_expression *expr, bool
> skip_body)
> {
> @@ -251,8 +257,11 @@ ir_reader::read_function_sig(ir_function *f,
> s_expression *expr, bool skip_body)
> ir_function_signature *sig =
> f->exact_matching_signature(&hir_parameters);
> if (sig == NULL && skip_body) {
> /* If scanning for prototypes, generate a new signature. */
> - sig = new(mem_ctx) ir_function_signature(return_type);
> - sig->is_builtin = true;
> + /* ir_reader doesn't know what languages support a given built-in,
> so
> + * just say that they're always available. For now, other
> mechanisms
> + * guarantee the right built-ins are available.
> + */
> + sig = new(mem_ctx) ir_function_signature(return_type,
> always_available);
> f->add_signature(sig);
> } else if (sig != NULL) {
> const char *badvar = sig->qualifiers_match(&hir_parameters);
> --
> 1.8.3.4
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev@lists.freedesktop.org
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>
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