A unit attribute is an attribute that represents a value of `unit` type. The
`unit` type allows only one value forming a singleton set. This attribute value
is used to represent attributes that only have meaning from their existence.
One example of such an attribute could be the `swift.self` attribute. This attribute indicates that a function parameter is the self/context
parameter. It could be represented as a boolean attribute(true or false), but a
value of false doesn't really bring any value. The parameter either is the
self/context or it isn't.
```mlir {.mlir}
// A unit attribute defined with the `unit` value specifier.
func @verbose_form(i1 {unitAttr : unit})
// A unit attribute can also be defined without the `unit` value specifier.
func @simple_form(i1 {unitAttr})
```
--
PiperOrigin-RevId: 245254045
other characters within the <>'s now that we can. This will allow quantized
types to use the pretty syntax (among others) after a few changes.
--
PiperOrigin-RevId: 243521268
There are no empty lines in output for three of these directives so removed
them and replaced the remaining one with 'CHECK-NOT:' as otherwise it is
failing with the following error.
error: found 'CHECK-EMPTY' without previous 'CHECK: line
TESTED = n/a
PiperOrigin-RevId: 243288605
making the IR dumps much nicer.
This is part 2/3 of the path to making dialect types more nice. Part 3/3 will
slightly generalize the set of characters allowed in pretty types and make it
more principled.
--
PiperOrigin-RevId: 242249955
restricted grammar. This will make certain common types much easier to read.
This is part tensorflow/mlir#1 of 2, which allows us to accept the new syntax. Part 2 will
change the asmprinter to automatically use it when appropriate, which will
require updating a bunch of tests.
This is motivated by the EuroLLVM tutorial and cleaning up the LLVM dialect aesthetics a bit more.
--
PiperOrigin-RevId: 242234821
have no standard ops for working with these yet, this is simply enough to
represent and round trip them in the printer and parser.
--
PiperOrigin-RevId: 241102728
Example:
%call:2 = call @multi_return() : () -> (f32, i32)
use(%calltensorflow/mlir#0, %calltensorflow/mlir#1)
This cl also adds parser support for uniquely named result values. This means that a test writer can now write something like:
%foo, %bar = call @multi_return() : () -> (f32, i32)
use(%foo, %bar)
Note: The printer will still print the collapsed form.
PiperOrigin-RevId: 240860058
Due to legacy reasons (ML/CFG function separation), regions in affine control
flow operations require contained blocks not to have terminators. This is
inconsistent with the notion of the block and may complicate code motion
between regions of affine control operations and other regions.
Introduce `affine.terminator`, a special terminator operation that must be used
to terminate blocks inside affine operations and transfers the control back to
he region enclosing the affine operation. For brevity and readability reasons,
allow `affine.for` and `affine.if` to omit the `affine.terminator` in their
regions when using custom printing and parsing format. The custom parser
injects the `affine.terminator` if it is missing so as to always have it
present in constructed operations.
Update transformations to account for the presence of terminator. In
particular, most code motion transformation between loops should leave the
terminator in place, and code motion between loops and non-affine blocks should
drop the terminator.
PiperOrigin-RevId: 240536998
Dialect attributes are defined as:
dialect-namespace `.` attr-name `:` attribute-value
Dialects can override any of the following hooks to verify the validity of a given attribute:
* verifyFunctionAttribute
* verifyFunctionArgAttribute
* verifyInstructionAttribute
PiperOrigin-RevId: 236507970
Associates opaque constants with a particular dialect. Adds general mechanism to register dialect-specific hooks defined in external components. Adds hooks to decode opaque tensor constant and extract an element of an opaque tensor constant.
This CL does not change the existing mechanism for registering constant folding hook yet. One thing at a time.
PiperOrigin-RevId: 233544757
Aggregate types where at least one dimension is zero do not fully make sense as
they cannot contain any values (their total size is zero). However, TensorFlow
and XLA support tensors with zero sizes, so we must support those too. This is
relatively safe since, unlike vectors and memrefs, we don't have first-class
element accessors for MLIR tensors.
To support sparse element attributes of vector types that have no non-zero
elements, make sure that index and value element attributes have tensor type so
that we never need to create a zero vector type internally. Note that this is
already consistent with the inline documentation of the sparse elements
attribute. Users of the sparse elements attribute should not rely on the
storage schema anyway.
PiperOrigin-RevId: 232896707
Existing IR syntax is ambiguous in type declarations in presence of zero sizes.
In particular, `0x1` in the type size can be interpreted as either a
hexadecimal literal corresponding to 1, or as two distinct decimal literals
separated by an `x` for sizes. Furthermore, the shape `<0xi32>` fails lexing
because it is expected to be an integer literal.
Fix the lexer to treat `0xi32` as an integer literal `0` followed by a bare
identifier `xi32` (look one character ahead and early return instead of
erroring out).
Disallow hexadecimal literals in type declarations and forcibly split the token
into multiple parts while parsing the type. Note that the splitting trick has
been already present to separate the element type from the preceding `x`
character.
PiperOrigin-RevId: 232880373
Existing type syntax contains the following productions:
function-type ::= type-list-parens `->` type-list
type-list ::= type | type-list-parens
type ::= <..> | function-type
Due to these rules, when the parser sees `->` followed by `(`, it cannot
disambiguate if `(` starts a parenthesized list of function result types, or a
parenthesized list of operands of another function type, returned from the
current function. We would need an unknown amount of lookahead to try to find
the `->` at the right level of function nesting to differentiate between type
lists and singular function types.
Instead, require the result type of the function that is a function type itself
to be always parenthesized, at the syntax level. Update the spec and the
parser to correspond to the production rule names used in the spec (although it
would have worked without modifications). Fix the function type parsing bug in
the process, as it used to accept the non-parenthesized list of types for
arguments, disallowed by the spec.
PiperOrigin-RevId: 232528361
In optional attribute dictionary used, among others, in the generic form of the
ops, attribute types for integers and floats are omitted. This could lead to
inconsistencies when round-tripping the IR, in particular the attributes are
created with incorrect types after parsing (integers default to i64, floats
default to f64). Provide API to emit a trailing type after the attribute for
integers and floats. Use it while printing the optional attribute dictionary.
Omitting types for i64 and f64 is a pragmatic decision that minimizes changes
in tests. We may want to reconsider in the future and always print types of
attributes in the generic form.
PiperOrigin-RevId: 232480116
- print multiplication by -1 as unary negate; expressions like s0 * -1, d0 * -1
+ d1 will now appear as -s0, -d0 + d1 resp.
- a minor cleanup while on printAffineExprInternal
PiperOrigin-RevId: 230222151
Originally, terminators were special kinds of operation and could not be
extended by dialects. Only builtin terminators were supported and they had
custom parsers and printers. Currently, "terminator" is a property of an
operation, making it possible for dialects to define custom terminators.
However, verbose forms of operation syntax were not designed to support
terminators that may have a list of successors (each successor contains a block
name and an optional operand list). Calling printDefaultOp on a terminator
drops all successor information. Dialects are thus required to provide custom
parsers and printers for their terminators.
Introduce the syntax for the list of successors in the verbose from of the
operation. Add support for printing and parsing verbose operations with
successors.
Note that this does not yet add support for unregistered terminators since
"terminator" is a property stored in AsbtractOperation and therefore is only
available for registered operations that have an instance of AbstractOperation.
Add tests for verbose parsing. It is currently impossible to test round-trip
for verbose terminators because none of the known dialects use verbose syntax
for printing terminators by default, however the printer was exercised on the
LLVM IR dialect prototype.
PiperOrigin-RevId: 228566453
Alias identifiers can be used in the place of the types that they alias, and are defined as:
type-alias-def ::= '!' alias-name '=' 'type' type
type-alias ::= '!' alias-name
Example:
!avx.m128 = type vector<4 x f32>
...
"foo"(%x) : vector<4 x f32> -> ()
// becomes:
"foo"(%x) : !avx.m128 -> ()
PiperOrigin-RevId: 228271372
Dialect specific types are registered similarly to operations, i.e. registerType<...> within the dialect. Unlike operations, there is no notion of a "verbose" type, that is *all* types must be registered to a dialect. Casting support(isa/dyn_cast/etc.) is implemented by reserving a range of type kinds in the top level Type class as opposed to string comparison like operations.
To support derived types a few hooks need to be implemented:
In the concrete type class:
- static char typeID;
* A unique identifier for the type used during registration.
In the Dialect:
- typeParseHook and typePrintHook must be implemented to provide parser support.
The syntax for dialect extended types is as follows:
dialect-type: '!' dialect-namespace '<' '"' type-specific-data '"' '>'
The 'type-specific-data' is information used to identify different types within the dialect, e.g:
- !tf<"variant"> // Tensor Flow Variant Type
- !tf<"string"> // Tensor Flow String Type
TensorFlow/TensorFlowControl types are now implemented as dialect specific types as a proof
of concept.
PiperOrigin-RevId: 227580052
The entire compiler now looks at structural properties of the function (e.g.
does it have one block, does it contain an if/for stmt, etc) so the only thing
holding up this difference is round tripping through the parser/printer syntax.
Removing this shrinks the compile by ~140LOC.
This is step 31/n towards merging instructions and statements. The last step
is updating the docs, which I will do as a separate patch in order to split it
from this mostly mechanical patch.
PiperOrigin-RevId: 227540453
printing the entry block in a CFG function's argument line. Since I'm touching
all of the testcases anyway, change the argument list from printing as
"%arg : type" to "%arg: type" which is more consistent with bb arguments.
In addition to being more consistent, this is a much nicer look for cfg functions.
PiperOrigin-RevId: 227240069
have a designator. This improves diagnostics and merges handling between CFG
and ML functions more. This also eliminates hard coded parser knowledge of
terminator keywords, allowing dialects to define their own terminators.
PiperOrigin-RevId: 227239398
the function signature, giving them common functionality to ml functions. This
is a strictly additive patch that adds new capability without changing behavior
in a significant way (other than a few diagnostic cleanups). A subsequent
patch will change the printer to use this behavior, which will require updating
a ton of testcases. :)
This exposes the fact that we need to make a grammar change for block
arguments, as is tracked by b/122119779
This is step 23/n towards merging instructions and statements, and one of the
first steps towards eliminating the "cfg vs ml" distinction at a syntax and
semantic level.
PiperOrigin-RevId: 227228342
River Riddle