Just like we try to fixup struct names for block types, inner structs
can be "anonymous" structs. HLSL codegen from DXC tends to emit this,
and emitting dummy struct names tends to break GL linkage on some
drivers.
Makes codegen from typical D3D emulation SPIR-V more readable.
Also makes cross compilation with NotEqual more sensible.
It's very rare to actually need the strict NaN-checks in practice.
Also, glslang now emits UnordNotEqual by default it seems, so give up
trying to assume OrdNotEqual. Harmonize for UnordNotEqual as the sane
default.
Introduces an idea of a recompilation making forward progress.
There are some extreme edge cases where we need more than 3 loops, but
only allow this in specific circumstances where we can reason about
forward progress being made.
This is somewhat awkward to support, but the best effort we can do here
is to analyze various Load/Store opcodes and deduce the ideal overall
alignment based on this. This is not a 100% perfect solution, but should
be correct for any reasonable use case.
Also fix various nitpicks with BDA support while I'm at it.
Apparently, it's legal to use a selection construct where both paths
branch to same location, but a different merge point is used.
This breaks many assumptions the variable scope analyzer makes.
The only logical way to generate code for this scenario is to treat the
selection construct as a trivial switch construct with only a default
case.
Need special workarounds to handle array load/store since array size is
unsized in GLSL, and array copy is not possible.
Also, consider bitcast for scalar loads and stores.
- Do not silently drop reserved identifiers in the parser. This makes it
possible to reflect identifiers which are reserved by the
cross-compiler module.
- Instead of dropping the name, emit _RESERVED_IDENTIFIER_FIXUP in the
source to make it clear that a name has been rewritten.
- Document what is reserved and not.
To facilitate an improved linking-by-name use case for older GL,
we will be more aggressive about merging struct definitions, even for
rather unrelated cases where we don't strictly need to use type aliases.
When inside a loop, treat any read of outer expressions to happen
multiple times, forcing a temporary of said outer expressions.
This avoids the problem where we can end up relying on loop-invariant code motion to happen in the
compiler when converting optimized shaders.
When we see a switch block which only contains one default block, emit a
do {} while(false) statement instead, which is far more idiomatic and
readable anyways.
