TLDR: This patch introduces a new kind of builtin, "a polymorphic builtin". One
calls it like any other builtin, e.x.:
```
Builtin.generic_add(x, y)
```
but it has a contract: it must be specialized to a concrete builtin by the time
we hit Lowered SIL. In this commit, I add support for the following generic
operations:
Type | Op
------------------------
FloatOrVector |FAdd
FloatOrVector |FDiv
FloatOrVector |FMul
FloatOrVector |FRem
FloatOrVector |FSub
IntegerOrVector|AShr
IntegerOrVector|Add
IntegerOrVector|And
IntegerOrVector|ExactSDiv
IntegerOrVector|ExactUDiv
IntegerOrVector|LShr
IntegerOrVector|Mul
IntegerOrVector|Or
IntegerOrVector|SDiv
IntegerOrVector|SRem
IntegerOrVector|Shl
IntegerOrVector|Sub
IntegerOrVector|UDiv
IntegerOrVector|Xor
Integer |URem
NOTE: I only implemented support for the builtins in SIL and in SILGen. I am
going to implement the optimizer parts of this in a separate series of commits.
DISCUSSION
----------
Today there are polymorphic like instructions in LLVM-IR. Yet, at the
swift and SIL level we represent these operations instead as Builtins whose
names are resolved by splatting the builtin into the name. For example, adding
two things in LLVM:
```
%2 = add i64 %0, %1
%2 = add <2 x i64> %0, %1
%2 = add <4 x i64> %0, %1
%2 = add <8 x i64> %0, %1
```
Each of the add operations are done by the same polymorphic instruction. In
constrast, we splat out these Builtins in swift today, i.e.:
```
let x, y: Builtin.Int32
Builtin.add_Int32(x, y)
let x, y: Builtin.Vec4xInt32
Builtin.add_Vec4xInt32(x, y)
...
```
In SIL, we translate these verbatim and then IRGen just lowers them to the
appropriate polymorphic instruction. Beyond being verbose, these prevent these
Builtins (which need static types) from being used in polymorphic contexts where
we can guarantee that eventually a static type will be provided.
In contrast, the polymorphic builtins introduced in this commit can be passed
any type, with the proviso that the expert user using this feature can guarantee
that before we reach Lowered SIL, the generic_add has been eliminated. This is
enforced by IRGen asserting if passed such a builtin and by the SILVerifier
checking that the underlying builtin is never called once the module is in
Lowered SIL.
In forthcoming commits, I am going to add two optimizations that give the stdlib
tool writer the tools needed to use this builtin:
1. I am going to add an optimization to constant propagation that changes a
"generic_*" op to the type of its argument if the argument is a type that is
valid for the builtin (i.e. integer or vector).
2. I am going to teach the SILCloner how to specialize these as it inlines. This
ensures that when we transparent inline, we specialize the builtin automatically
and can then form SSA at -Onone using predictable memory access operations.
The main implication around these polymorphic builtins are that if an author is
not able to specialize the builtin, they need to ensure that after constant
propagation, the generic builtin has been DCEed. The general rules are that the
-Onone optimizer will constant fold branches with constant integer operands. So
if one can use a bool of some sort to trigger the operation, one can be
guaranteed that the code will not codegen. I am considering putting in some sort
of diagnostic to ensure that the stdlib writer has a good experience (e.x. get
an error instead of crashing the compiler).
Most of AST, Parse, and Sema deal with FileUnits regularly, but SIL
and IRGen certainly don't. Split FileUnit out into its own header to
cut down on recompilation times when something changes.
No functionality change.
1. builtin "int_expect", which makes the evaluator work on more
integer operations such as left/right shift (with traps) and
integer conversions.
2. builtin "_assertConfiguration", which enables the evaluator
to work with debug stdlib.
3. builtin "ptrtoint", which enables the evaluator to track
StaticString
4. _assertionFailure API, which enables the evaluator to report
stdlib assertion failures encountered during constant evaluation.
Also, enable attaching auxiliary data with the enum "UnknownReason"
and use it to improve diagnostics for UnknownSymbolicValues,
which represent failures during constant evaluation.
This memoizes the result, which is fine for all callers; the only
exception is open existential types where each new open existential
now explicitly gets a unique generic environment, allocated by
calling GenericEnvironment::getIncomplete().
Returns `true` if `T.Type` is known to refer to a concrete type. The
implementation allows for the optimizer to specialize this at -O and
eliminate conditional code.
Includes `Swift._isConcrete<T>(T.Type) -> Bool` wrapper function.
We have to be source compatible to be able to parse old swiftinterface files where the old Builtin.condfail is used in inlineable functions.
rdar://problem/53176692
The SIL generation for this builtin also changes: instead of generating the cond_fail instructions upfront, let the optimizer generate it, if the operand is a static string literal.
In worst case, if the second operand is not a static string literal, the Builtin.condfail is lowered at the end of the optimization pipeline with a default message: "unknown program error".
The SIL generation for this builtin also changes: instead of generating the cond_fail instructions upfront, let the optimizer generate it, if the operand is a static string literal.
In worst case, if the second operand is not a static string literal, the Builtin.condfail is lowered at the end of the optimization pipeline with a default message: "unknown program error".
String -> Builtin.RawPointer that given a string constructed from a
literal, returns the address of the string literal in the global string
table of the compiled binary as a pointer.
These changes allow to optionally perform a very fast build that is targeted to only produce the syntax parser library.
Part of addressing rdar://48153331
Intrinsics never have custom function type ExtInfo anymore. (This used
to be where the "noreturn" bit lived, but now that's represented by
Swift.Never.)
No functionality change.
Looking these up is slow because the attribute lists get rebuilt and
reuniqued in the LLVM context each time. Saving them is a single
pointer per IntrinsicInfo and IntrinsicInfos are already cached in
each SILModule.
This shaves about 4s off optimizing the standard library (72s out of a
3:00+ build), and probably has much less effect anywhere else. That
is, it's not /really/ important after all, but it was an easy bit of
the profile to hammer down.
* Remove apparently obsolete builtin functions.
- Remove s_to_u_checked_conversion and u_to_s_checked_conversion functions from builtin AST parsing, SIL/IR generation and from SIL optimisations.
* Remove apparently obsolete builtin functions - unit tests.
- Remove unit tests for SIL transformations relating to s_to_u_checked_conversion and u_to_s_checked_conversion builtin functions.
`#assert` is a new static assertion statement that will let us write
tests for the new constant evaluation infrastructure that we are working
on. `#assert` works by lowering to a `Builtin.poundAssert` SIL
instruction. The constant evaluation infrastructure will look for these
SIL instructions, const-evaluate their conditions, and emit errors if
the conditions are non-constant or false.
This commit implements parsing, typechecking and SILGen for `#assert`.
The goal here is for the SILGen of these builtins to receive an owned
value so that it will perform an owned->owned conversion and therefore
produce a +1 result, as generally expected. Without this, SILGen will
perform a borrowed->borrowed conversion, and the copy of the result (if
it even happens) may happen after the argument's borrow scope has ended.
`\.self` is the final chosen syntax. Implement support for this syntax, and remove the stopgap builtin and `WritableKeyPath._identity` property that were in place before.
Visual Studio's compiler has a hard limit on the number of if/else if cascading
blocks at 128 elements (https://msdn.microsoft.com/en-us/library/dcda4f64.aspx).
Use `llvm::StringSwitch` which is both easier to read (although less imported in
this case due to the macro generation) and allows us to avoid this limit.
Parsed declarations would create an untyped 'self' parameter;
synthesized, imported and deserialized declarations would get a
typed one.
In reality the type, if any, depends completely on the properties
of the function in question, so we can just lazily create the
'self' parameter when needed.
If the function already has a type, we give it a type right there;
otherwise, we check if a 'self' was already created when we
compute a function's type and set the type of 'self' then.
Make sure the implementation can handle a key path with zero components by removing inappropriate assumptions that the number of components is always non-empty. Identity key paths also need some special behavior:
- Appending an identity key path should be an identity operation for the other operand
- Identity key paths have a `MemoryLayout.offset(of:)` zero
- Identity key paths interop with KVC as key paths to `@"self"`
To be able to exercise and test this behavior, add a `Builtin.identityKeyPath()` function and `WritableKeyPath._identity` accessor in lieu of finalized syntax.
This makes it easier to grep for and eventually remove the
remaining usages.
It also allows you to write FunctionType::get({}, ...) to call the
ArrayRef overload empty parameter list, instead of picking the Type
overload and calling it with an empty Type() value.
While I"m at it, in a few places instead of renaming just clean up
usages where it was completely mechanical to do so.
There are two general constructor forms here:
- One took the number of parameter lists, to be filled in later.
Now, this takes a boolean indicating if there is an implicit
'self'.
- The other one took the actual parameter lists and filled them
in right away. This now takes a separate 'self' ParamDecl and
ParameterList.
Instead of storing the number of parameter lists, an
AbstractFunctionDecl now only needs to store if there is a 'self'
or not.
I've updated most places that construct AbstractFunctionDecls to
properly use these new forms. In the ClangImporter, there is
more code that remains to be untangled, so we continue to build
multiple ParameterLists and unpack them into a ParamDecl and
ParameterList at the last minute.
