It seems that the NVIDIA drivers leaves VBVs bindings untouched
when they are NULL (or the GPU buffer address is NULL), instead of
setting them to a null binding.
Differently from other cases of inconsistent behaviour between AMD
and NVIDIA, here I'm explicitly marking the NVIDIA behaviour as
broken, because the expected behaviour is spelled out explicitly
(at least for the D3D12 specification standards).
The code doesn't make sense in the first place, even if it's
accepted by the compiler, so it makes sense that the behaviour
is undefined. And indeed the behaviour is different on AMD (4 is
returned), NVIDIA (QNaN is returned) and WARP (device is removed).
Currently program errors might result on instructions that use
ctx->error_instr as src. In case we hit YYABORT while parsing another
part of the HLSL source, we have to make sure that the block that
contains the instruction is properly cleaned up, or we might hit the
vkd3d:590273:err:hlsl_free_instr Failed assertion: list_empty(&node->uses)
assertion when hlsl_ctx_cleanup() is called after the YYABORT.
Consider the following shader:
float4 main() : sv_target
{
// Statement A
int p = foo; // initializer argument is ERROR.
// Statement B
undeclared_fun(); // triggers YYABORT.
}
Statement A will src the ctx->error_instr because of the undeclared
identifier and Statement B will trigger an YYABORT because of the
undeclared function.
