glsl: Simplify aggregate type inference to prepare for ARB_arrays_of_arrays.

Most of the time it is not necessary to perform type inference to
compile GLSL; the type of every expression can be inferred from the
contents of the expression itself (and previous type declarations).
The exception is aggregate initializers: their type is determined by
the LHS of the variable being assigned to.  For example, in the
statement:

   mat2 foo = { { 1, 2 }, { 3, 4 } };

the type of { 1, 2 } is only known to be vec2 (as opposed to, say,
ivec2, uvec2, int[2], or a struct) because of the fact that the result
is being assigned to a mat2.

Previous to this patch, we handled this situation by doing some type
inference during parsing: when parsing a declaration like the one
above, we would call _mesa_set_aggregate_type(), which would infer the
type of each aggregate initializer and store it in the corresponding
ast_aggregate_initializer::constructor_type field.  Since this
happened at parse time, we couldn't do the type inference using
glsl_type objects; we had to use ast_type_specifiers, which are much
more awkward to work with.  Things are about to get more complicated
when we add support for ARB_arrays_of_arrays.

This patch simplifies things by postponing the call to
_mesa_set_aggregate_type() until ast-to-hir time, when we have access
to glsl_type objects.  As a side benefit, we only need to have one
call to _mesa_set_aggregate_type() now, instead of six.

Reviewed-by: Matt Turner <[email protected]>

1 files changed, 3 insertions, 5 deletions

diff --git a/src/glsl/ast_function.cpp b/src/glsl/ast_function.cpp
index 2d05d072341..4c5b0e4aa90 100644
--- a/src/glsl/ast_function.cpp
+++ b/src/glsl/ast_function.cpp
@@ -1687,14 +1687,12 @@ ast_aggregate_initializer::hir(exec_list *instructions,
 {
    void *ctx = state;
    YYLTYPE loc = this->get_location();
-   const char *name;
 
    if (!this->constructor_type) {
       _mesa_glsl_error(&loc, state, "type of C-style initializer unknown");
       return ir_rvalue::error_value(ctx);
    }
-   const glsl_type *const constructor_type =
-      this->constructor_type->glsl_type(&name, state);
+   const glsl_type *const constructor_type = this->constructor_type;
 
    if (!state->ARB_shading_language_420pack_enable) {
       _mesa_glsl_error(&loc, state, "C-style initialization requires the "
@@ -1702,12 +1700,12 @@ ast_aggregate_initializer::hir(exec_list *instructions,
       return ir_rvalue::error_value(ctx);
    }
 
-   if (this->constructor_type->is_array) {
+   if (constructor_type->is_array()) {
       return process_array_constructor(instructions, constructor_type, &loc,
                                        &this->expressions, state);
    }
 
-   if (this->constructor_type->structure) {
+   if (constructor_type->is_record()) {
       return process_record_constructor(instructions, constructor_type, &loc,
                                         &this->expressions, state);
    }