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Over the last few years, the compiler has grown to support 7 different
language versions and 6 extensions that add new built-in types. With
more and more features being added, some of our core code has devolved
into an unmaintainable spaghetti of sorts.
A few problems with the old code:
1. Built-in types are declared...where exactly?
The types in builtin_types.h were organized in arrays by the language
version or extension they were introduced in. It's factored out to
avoid duplicates---every type only exists in one array. But that
means that sampler1D is declared in 110, sampler2D is in core types,
sampler3D is a unique global not in a list...and so on.
2. Spaghetti call-chains with weird parameters:
generate_300ES_types calls generate_130_types which calls
generate_120_types and generate_EXT_texture_array_types, which calls
generate_110_types, which calls generate_100ES_types...and more
Except that ES doesn't want 1D types, so we have a skip_1d parameter.
add_deprecated also falls into this category.
3. Missing type accessors.
Common types have convenience pointers (like glsl_type::vec4_type),
but others may not be accessible at all without a symbol table (for
example, sampler types).
4. Global variable declarations in a header file?
#include "builtin_types.h" in two C++ files would break the build.
The new code addresses these problems. All built-in types are declared
together in a single table, independent of when they were introduced.
The macro that declares a new built-in type also creates a convenience
pointer, so every type is available and it won't get out of sync.
The code to populate a symbol table with the appropriate types for a
particular language version and set of extensions is now a single
table-driven function. The table lists the type name and GL/ES versions
when it was introduced (similar to how the lexer handles reserved
words). A single loop adds types based on the language version.
Explicit extension checks then add additional types. If they were
already added based on the language version, glsl_symbol_table simply
ignores the request to add them a second time, meaning we don't need
to worry about duplicates and can simply list types where they belong.
v2: Mark uvecs and shadow samplers as ES3 only, and 1DArrayShadow as
unsupported in ES entirely. Add a touch more doxygen.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
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