Summary:
In some cases, one may want to use different names for C++ symbol of an
enumerand from its string representation. In particular, in the LLVM dialect
for, e.g., Linkage, we would like to preserve the same enumerand names as LLVM
API and the same textual IR form as LLVM IR, yet the two are different
(CamelCase vs snake_case with additional limitations on not being a C++
keyword).
Modify EnumAttrCaseInfo in OpBase.td to include both the integer value and its
string representation. By default, this representation is the same as C++
symbol name. Introduce new IntStrAttrCaseBase that allows one to use different
names. Exercise it for LLVM Dialect Linkage attribute. Other attributes will
follow as separate changes.
Differential Revision: https://reviews.llvm.org/D73362
BitEnumAttr is a mechanism for modelling attributes whose value is
a bitfield. It should not be scoped to the SPIR-V dialect and can
be used by other dialects too.
This CL is mostly shuffling code around and adding tests and docs.
Functionality changes are:
* Fixed to use `getZExtValue()` instead of `getSExtValue()` when
getting the value from the underlying IntegerAttr for a case.
* Changed to auto-detect whether there is a case whose value is
all bits unset (i.e., zero). If so handle it specially in all
helper methods.
PiperOrigin-RevId: 277964926
In ODS, right now we use StringAttrs to emulate enum attributes. It is
suboptimal if the op actually can and wants to store the enum as a
single integer value; we are paying extra cost on storing and comparing
the attribute value.
This CL introduces a new enum attribute subclass that are backed by
IntegerAttr. The downside with IntegerAttr-backed enum attributes is
that the assembly form now uses integer values, which is less obvious
than the StringAttr-backed ones. However, that can be remedied by
defining custom assembly form with the help of the conversion utility
functions generated via EnumsGen.
Choices are given to the dialect writers to decide which one to use for
their enum attributes.
PiperOrigin-RevId: 255935542
Enum attributes can be defined using `EnumAttr`, which requires all its cases
to be defined with `EnumAttrCase`. To facilitate the interaction between
`EnumAttr`s and their C++ consumers, add a new EnumsGen TableGen backend
to generate a few common utilities, including an enum class, `llvm::DenseMapInfo`
for the enum class, conversion functions from/to strings.
This is controlled via the `-gen-enum-decls` and `-gen-enum-defs` command-line
options of `mlir-tblgen`.
PiperOrigin-RevId: 252209623
Alex Zinenko