* Improve algorithm to reorder blocks in a function
In dead branch elimination, blocks can end up in a the wrong order, so
there is code to reorder the blocks in structured order. The problem is
that the algorithm to do that is very poor. It involves many searchs in
the function for the correct position to place the block, as well as
moving many block in the vector.
The solution is to write a specialized function in the function class
that will reorder the blocks in structured order. After computing the
structured order, reordering the block can be done in linear time, with
very little overhead.
* No longer blindly add global non-semantic info instructions to global
types and values
* functions now have a list of non-semantic instructions that succeed
them in the global scope
* global non-semantic instructions go in global types and values if
they appear before any function, otherwise they are attached to the
immediate function predecessor in the module
* changed ADCE to use the function removal utility
* Modified EliminateFunction to have special handling for non-semantic
instructions in the global scope
* non-semantic instructions are moved to an earlier function (or full
global set) if the function they are attached to is eliminated
* Added IRContext::KillNonSemanticInfo to remove the tree of
non-semantic instructions that use an instruction
* this is used in function elimination
* There is still significant work in the optimizer to handle
non-semantic instructions fully in the optimizer
* Move ProcessFunction* function from pass to the context.
There are a few functions that are used to traverse the call tree.
They currently live in the Pass class, but they have nothing to do with
a pass, and may be needed outside of a pass. They would be better in
the ir context, or in a specific call tree class if we ever have a need
for it.
* Don't inline recursive functions.
Inlining does not check if a function is recursive or not. This has
been fine as long as the shader was a Vulkan shader, which forbid
recursive functions. However, not all shaders are vulkan, so either
we limit inlining to Vulkan shaders or we teach it to look for recursive
functions.
I prefer to keep the passes as general as is reasonable. The change
does not require much new code in inlining and gives a reason to refactor
some other code.
The changes are to add a member function to the Function class that
checks if that function is recursive or not.
Then this is used in inlining to not inlining a function call if it calls
a recursive function.
* Add id to function analysis
There are a few places that build a map from ids to Function whose
result is that id. I decided to add an analysis to the context for this
to reduce that code, and simplify some of the functions.
* Add missing file.
