xvalue symbols refer to two expressions: an lvalue and an rvalue. They
are meant to be used with xvalue expressions.
xvalue expressions are useful when a distinction must be made between
the behavior of something (eg, a pascal function symbol) must change
depending on whether it's an lvalue (assignment of the function's return
value) or an rvalue (a call to the function, especially when the
function takes no parameters).
Because the glsl front-end uses Ruamoko to compile its builtins, it
needs to switch languages, and the cleanest way to do so is to use a
context object that gets passed around. This removes not only the
current_language global, but also (as a bonus) any real references to
flex's scanner object (there's still a pointer in rua_ctx_t, but it's no
longer a parameter (which caused some pain in the change)).
While it is a pessimism, I really want to get rid of fold_constants (in
favor of something smarter), and it's currently in the way of more
important things.
The main goal was to make it possible to give generic functions
definitions (since the code would be very dependent on the actual
parameter types), but will also allow for inline functions. It also
helped move a lot of the back-end dependent code out of semantics
processing and almost completely (if not completely) out of the parser.
Possibly more importantly, it gets the dags flushing out of the parser,
which means such is now shared by all front-ends.
There's probably a lot of dead code in expr.c now, but that can be taken
care of another time.
When getting an offset alias of an already aliased def, the offset needs
to be updated so it points to the correct part of the def. This is
actually a rather old bug but it got uncovered somehow with my rework of
the ruamoko semantic processing (probably an altered cast).
I guess I'd wanted to avoid supporting automatic types in type
functions, but that broke long and unsigned int: either no type, or just
int, depending on the decl style.
Unfortunately, it turns out that generic functions are over-grouped so
all functions with the same name get the last definition, so `mix` with
a float (which should get GLSLstd450FMix) gets the bool version instead
(SpvOpSelect).
When the number of supplied vectors matches the number of columns in the
matrix and all vectors have the same width as the number of rows in the
matrix, there's no need to expand the vectors into components only to be
gathered again.
SPIR-V requires that matrices are constructed from vectors rather than
individual components. While not optimal, iqm.vert's output now passes
spirv-val. Also probably still lots wrong with fine details.
I think I need to come up with a better way of defining glsl builtins
and the strings are rather ugly (and I don't want to use qfcc system
header files).
iqm.vert now compiles, but doesn't pass validation yet (matrix bugs).
And, nicely, simplify it quite a bit. I'm not sure why I didn't thinkg
of this approach before. While the ruamoko back-end doesn't support
matrices yet, the expressions are handled.
As a side effect, type checking on comparisons is "stricter" in that
more potentially bogus comparisons (eg, int-float) are caught, resulting
in a few warnings in ruamoko code and even finding a couple of bugs.
Using bit masks for valid source types for each destination type makes
the logic a lot easier to read. Still had to have some explicit checks
for enums and bools.
The code gen return statements checks for out/inout parameters in the
current function and thus could result in some undesired behavior when
constants are evaluated within such a function.
I found a need to check for shifts separately (not sure it's the right
approach for that problem, though), and there are a few more math ops
than just +-*/.
I'm not sure what it's useful for, but GLSL has a function for it thus I
decided to add the instruction to the VM, so this is part of the
compiler side.
The tricky bit was figuring out how to get `floor()` out of the
available instructions. It's handy that the comparison ops always
returned floats and didn't force the use of branches.
Now both width and columns must match for an instruction to be selected.
Found a few errors in my opcode specs, and some minor goofs in the type
system (really just overthinking things when I added matrices).
