Some languages allow a restricted set of user structure types returned from texture sampling
operations. Restrictions include the total vector size of all components may not exceed 4,
and the basic types of all members must be identical.
This adds underpinnings for that ability. Because storing a whole TType or even a simple
TTypeList in the TSampler would be expensive, the structure definition is held in a
table outside the TType. The TSampler contains a small bitfield index, currently 4 bits
to support up to 15 separate texture template structure types, but that can be adjusted
up or down. Vector returns are handled as before.
There are abstraction methods accepting and returning a TType (such as may have been parsed
from a grammar). The new methods will accept a texture template type and set the
sampler to the structure if possible, checking a range of error conditions such as whether
the total structure vector components exceed 4, or whether their basic types differe, or
whether the struct contains non-vector-or-scalar members. Another query returns the
appropriate TType for the sampler.
High level summary of design:
In the TSampler, this holds an index into the texture structure return type table:
unsigned int structReturnIndex : structReturnIndexBits;
These are the methods to set or get the return type from the TSampler. They work for vector or structure returns, and potentially could be expanded to handle other things (small arrays?) if ever needed.
bool setTextureReturnType(TSampler& sampler, const TType& retType, const TSourceLoc& loc);
void getTextureReturnType(const TSampler& sampler, const TType& retType, const TSourceLoc& loc) const;
The ``convertReturn`` lambda in ``HlslParseContext::decomposeSampleMethods`` is greatly expanded to know how to copy a vec4 sample return to whatever the structure type should be. This is a little awkward since it involves introducing a comma expression to return the proper aggregate value after a set of memberwise copies.
Semantic test left over from other source languages is removed, since this is permitted by HLSL.
Also, to support the functionality, a targeted test is performed for this case and it is
turned into a EvqGlobal qualifier to create an AST initialization segment when needed.
Constness is now propagated up aggregate chains during initializer construction. This
handles hierarchical cases such as the distinction between:
static const float2 a[2] = { { 1, 2 }, { 3, 4} };
vs
static const float2 a[2] = { { 1, 2 }, { cbuffer_member, 4} };
The first of which can use a first class constant initalization, and the second cannot.
Lays the groundwork for fixing issue #954.
Partial flattenings were previously tracked through a stack of active subsets
in the parse context, but full functionality needs AST nodes to represent
this across time, removing the need for parsecontext tracking.
This adds infrastructure suitable for any front end to create SPIR-V loop
control flags. The only current front end doing so is HLSL.
[unroll] turns into spv::LoopControlUnrollMask
[loop] turns into spv::LoopControlDontUnrollMask
no specification means spv::LoopControlMaskNone
This is WIP, heavy on the IP part. There's not yet enough to use in real workloads.
Currently present:
* Creation of separate counter buffers for structured buffer types needing them.
* IncrementCounter / DecrementCounter methods
* Postprocess to remove unused counter buffers from linkage
* Associated counter buffers are given @count suffix (invalid as a user identifier)
Not yet present:
* reflection queries to obtain bindings for counter buffers
* Append/Consume buffers
* Ability to use SB references passed as fn parameters
Improves foundation for adding scalar casts.
Makes handle/make names more sane, better commented, uses more
precise subclass typing, and removes mutual recursion between
converting initializer lists and making constructors.
Previously, patch constant functions only accepted OutputPatch. This
adds InputPatch support, via a pseudo-builtin variable type, so that
the patch can be tracked clear through from the qualifier.
The prior implementation of GS did not work with the new EP wrapping architecture.
This fixes it: the Append() method now looks up the actual output rather
than the internal sanitized temporary type, and writes to that.
Unknown how extensive the semantics need to be yet. Need real
feedback from workloads. This is just done as part of unifying it
with the class/struct namespaces and grammar productions.
It would have been possible for globally scoped user functions to collide
with builtin method names. This adds a prefix to avoid polluting the
namespace.
Ideally this would be an invalid character to use in user identifiers, but
as that requires changing the scanner, for the moment it's an unlikely yet
valid prefix.
Also use this to move deferred member-function-body parsing to a better
place.
This should also be well poised for implementing the 'namespace' keyword.
This is needed for accessing types/variables within a member function body that are
not known until after the struct is finished being declared. However, that funtionality
is not yet present, this is just the deferred processing, which is working for
static member functions.
