These are only ever used with ShaderCode instances and nothing else.
Given that, we can convert these helper functions to expect that type of
object as an argument and remove the need for templates, improving
compiler throughput a marginal amount, as the template instantiation
process doesn't need to be performed.
We can also move the definitions of these functions into the cpp file,
which allows us to remove a few inclusions from the ShaderGenCommon
header. This uncovered a few instances of indirect inclusions being
relied upon in other source files.
One other benefit is this allows changes to be made to the definitions
of the functions without needing to recompile all translation units that
make use of these functions, making change testing a little quicker.
Moving the definitions into the cpp file also allows us to completely
hide DefineOutputMember() from external view, given it's only ever used
inside of GenerateVSOutputMembers().
Currently, when immediately compile shaders is not enabled, the
ubershaders will be placed before any specialized shaders in the compile
queue in hybrid ubershaders mode. This means that Dolphin could
potentially use the ubershaders for a longer time than it would have if
we blocked startup until all shaders were compiled, leading to a drop in
performance.
- In D3D, shaders could be compiled on the main thread, blocking
startup.
- Reduced the latency between a pipeline being requested and used in all
backends in hybrid ubershader mode, when no shader stages were present.
- Fixed a case where async compilation could cause the same UID to be
appended multiple times to the UID cache.
- Fix incorrect number of threads being used when immediately compile
shaders was enabled.
This enables shaders to be compiled while the game is starting, instead
of blocking startup. If a shader is needed before it is compiled,
emulation will block.
As these are stored in a map, operator< will become a hot function when
doing lookups, which happen every frame. std::tie generated a rather
large function here with quite a few branches.
