This is encoded as a primitive AIR instruction to resolve one corner
case: A function may include a `catch { ... }` or `else |err| { ... }`
block but not call any errorable fn. In that case, there is no error
return trace to save the index of and codegen needs to avoid
interacting with the non-existing error trace.
By using a primitive AIR op, we can depend on Liveness to mark this
unused in this corner case.
'Self' isn't a very good name to describe what it does.
This commit changes the type name into `CodeGen` and the parameter
to `func` as we're generating code for a function.
With this change, the backend's coding style is in line with the
self-hosted Wasm-linker.
When we return an operand directly as a result, we must call
`reuseOperand`. This commit ensures it's done for all currently-
implemented AIR instructions.
Rather than accepting a canonical branch and a target branch
we allow to directly merge a branch into the parent branch.
This is possible as there's no overlapping and we have infinite
registers to our availability. This makes merging a lot simpler.
When determining the type of a local (read: register), we would
previously subtract the stack locals also. However, this locals
are also within the same `locals` list, meaning the type of the
local we were retrieving was off by 2. This could create a validation
error when we re-use a local of a different type.
Upon a branch, we only allow locals to be freed which were allocated
within the same branch as where they die. This ensures that when two
or more branches target the same operand we do not try to free
it more than once. This does however not implement freeing the local
upon branch merging yet.
When reusing an operand it increases the reference count, then when
an operand dies it will only decrease the reference count. When
this reaches 0, the local will be virtually freed, meaning it can be
re-used for a new local.
By reference counting the locals, we can ensure that when we free
a local, no local will be reused while it still has references pointing
to it. This prevents misscompilations. The compiler will also panic if
we free a local more than we reference it, introducing extra safety to
ensure they match up.
This hooks reusal of locals into liveness analysis.
Meaning that when an operand dies, and is a local,
it will automatically be freed so it can be re-used
when a new local is required. The result of this, is
a lower allocation required for locals. Having less
locals means smaller binary size, as well as faster
compilation speed when loaded by the runtime.
This also fixes performing relocations for data symbols
of which the target symbol exists in an external object file.
We do this by checking if the target symbol was discarded,
and if so: get the new location so that we can find the
corresponding atom that belongs to said new location. Previously
it would always assume the symbol would live in the same file
as the atom/symbol that is doing the relocation.
Rather than storing it in a local and returning that,
we now keep this on the stack as all internal functions
expect it to be on the stack already and therefore were
generating extra `local.set` instructions.
When a local is no longer referenced or used, free it
so the local can be re-used by another instruction.
This means we generate less locals. Freeing this local
is a manual action and must only be used on temporaries
or where we are sure the local is not referenced by a
different AIR instruction, as that creates UB.
We now also no longer store a `WValue` when its tag is set to `none`
as those may never be referenced by any AIR instruction.
An assertion is done to make sure we never store a reference to a
`stack` value in our resolved instructions.
We internally use a lot of `load`'s that used to put
the result in a newly created local. For instance, when is considered
byRef or when we need a specific field/element/bytes from a larger type.
However, sometimes we want to directly use this value and then forget about
it, which means storing it in a local first is wasted instructions as well
as wasted locals that shouldn't be generated in the first place.
With this change it's explicit and requires the usage of `toLocal`.
This also does it for `wrapBinOp` which internally uses the already
refactored `binOp` and `wrapOperand` heavily simplifying this
function and not duplicate the logic from `binOp`
By keeping the result on the stack, we prevent codegen
from generating unneccesary locals when we have subsequent instructions
that do not have to be re-used.
Rather than always creating a new local and storing the result of
a binary operation into said local, we now leave it on top of the stack.
This allows for better codegen as we need less instructions, as well
as less total amount of locals.
When a local is no longer needed (for instance, it was used as
a temporary during arithmetic), it can be appended to one of
the typed freelists. This allows us to re-use locals and therefore
require less locals, reducing the binary size, as well as runtime
initialization.
Removed the copy of param_names inside of Fn and changed to
implementation of getParamName to fetch to parameter name from the ZIR.
The signature of getParamName was also changed to take an additional
*Module argument.
Rather than lowering float negation as `0.0 - x`.
* Add AIR instruction for float negation.
* Add compiler-rt functions for f128, f80 negation
closes#11853
`genFunctype` now accepts calling convention, param types, and return type
as part of its function signature rather than `fnData`. This means
we no longer have to create a dummy for our intrinsic call abstraction.
This also adds support for f16 division and builtins such as `@ceil` & more.
Implements `@mulAdd` for floats with bitsize 16, where it generates
a call into compiler-rt's `fmaf` function. Note that arguments
for fmaf are different in order than `@mulAdd`.
This implements binary operations and comparisons
for floats with bitsize 16. It does this by calling into
compiler-rt to first extend the float to 32 bits, perform the operation,
and then finally truncate back to 16 bits. When loading and storing the f16,
we do this as an unsigned 16bit integer.
Implements the creation of an undefined symbol for a compiler-rt intrinsic.
Also implements the building of the function call to said compiler-rt intrinsic.
Rather than storing all the shifts in temporaries, we perform the correct
shifting without temporaries. This makes the runtime code more performant
and also the backend code is simplified as we have a singular abstraction.
This does however not support floats of bitsizes
different than 32 or 64. f16, f80, f126 will require
support for compiler-rt and are out-of-scope for this commit.
Signed integers are currently not supported either.
