Rewrite how IDs are iterated over.

This is a fairly fundamental change on how IDs are handled.
It serves many purposes:

- Improve performance. We only need to iterate over IDs which are
  relevant at any one time.
- Makes sure we iterate through IDs in SPIR-V module declaration order
  rather than ID space. IDs don't have to be monotonically increasing,
  which was an assumption SPIRV-Cross used to have. It has apparently
  never been a problem until now.
- Support LUTs of structs. We do this by interleaving declaration of
  constants and struct types in SPIR-V module order.

To support this, the ParsedIR interface needed to change slightly.
Before setting any ID with variant_set<T> we let ParsedIR know
that an ID with a specific type has been added. The surface for change
should be minimal.

ParsedIR will maintain a per-type list of IDs which the cross-compiler
will need to consider for later.

Instead of looping over ir.ids[] (which can be extremely large), we loop
over types now, using:

ir.for_each_typed_id<SPIRVariable>([&](uint32_t id, SPIRVariable &var) {
	handle_variable(var);
});

Now we make sure that we're never looking at irrelevant types.

1 files changed, 1 insertions, 1 deletions

diff --git a/spirv_hlsl.hpp b/spirv_hlsl.hpp
index 67243637..8b777de3 100644
--- a/spirv_hlsl.hpp
+++ b/spirv_hlsl.hpp
@@ -148,7 +148,7 @@ private:
 	void emit_uniform(const SPIRVariable &var) override;
 	void emit_modern_uniform(const SPIRVariable &var);
 	void emit_legacy_uniform(const SPIRVariable &var);
-	void emit_specialization_constants();
+	void emit_specialization_constants_and_structs();
 	void emit_composite_constants();
 	void emit_fixup() override;
 	std::string builtin_to_glsl(spv::BuiltIn builtin, spv::StorageClass storage) override;