A struct declaration with variables is now absorbed into the 'declaration'
rule, like any other variable declaration.
A struct declaration without variables is now reduced to the
'struct_declaration_without_vars' rule.
They both are reduced to a 'declaration_statement' in the end.
In a declaration with multiple variables, the variables must be created
before the initializer of the next variable is parsed. This is required
for initializers such as:
float a = 1, b = a, c = b + 1;
A requisite for this is that the type information is parsed in the same
rule as the first variable (as a variable_def_typed) so it is
immediately available to declare the first variable. Then, the next
untyped variable declaration is parsed, and the type from the first
variable can be used to declare the second, before the third is parsed,
and so on.
Non-constant vector indexing is not solved with relative addressing
in the register indexes because this indexation cannot be at the level
of register-components.
Mathematical operations must be used instead.
Currently, the compiler requires that dereferences be HLSL_IR_CONSTANT, so that
it can compute the offset at compile time. However, scenarios such as this test
will produce a dereference with HLSL_IR_EXPR, which will generate an error.
Passing this test in particular will require adding support for SM4 relative
addressing, as well as support for non-constant indexing in general.
Signed-off-by: Ethan Lee <flibitijibibo@gmail.com>
In Shader Model 6 each signature element can span a range of register
indices, or 'rows', and system values do not share a register index with
non-system values. Inputs and outputs are referenced by element index
instead of register index. This patch merges multiple signature elements
into a single element under the following conditions:
- The register index in a load or store is specified dynamically by
including a relative address parameter with a base register index. The
dcl_index_range instruction is used to identify these.
- A register declaration is split across multiple elements which declare
different components of the register.
- A patch constant function writes tessellation factors. These are an
array in SPIR-V, but in SM 5.x each factor is declared as a separate
register, and these are dynamically indexed by the fork/join instance
id. Elimination of multiple fork/join phases converts the indices to
constants, but merging the signature elements into a single arrayed
element matches the SPIR-V output.
All references to input/output register indices are converted to element
indices. If a relative address is present, the element index is moved up
a slot so it cannot be confused with a constant offset. Existing code
only handles register index relative addressing for tessellation factors.
This patch adds generic support for it.
The new fixmes can be triggered in presence of object components within
structs (for SM5).
In shaders such as this one:
struct apple
{
Texture2D tex : TEX;
float4 color : COLOR;
};
float4 main(struct apple input) : sv_target
{
return input.tex.Load(int3(1, 2, 3));
}
Or this one:
struct
{
Texture2D tex;
float4 color;
} s;
float4 main() : sv_target
{
return s.tex.Load(int3(1, 2, 3));
}
Variables that contain more than one object (arrays or structs) require
the allocation of contiguous registers in the respective object
register spaces.
