This models a one or multi-dimensional C/C++ array.
The type implements the `ShapedTypeInterface` and prints similar to
memref/tensor:
```
%arg0: !emitc.array<1xf32>,
%arg1: !emitc.array<10x20x30xi32>,
%arg2: !emitc.array<30x!emitc.ptr<i32>>,
%arg3: !emitc.array<30x!emitc.opaque<"int">>
```
It can be translated to a C array type when used as function parameter
or as `emitc.variable` type.
This removes the type from EmitC's opaque attribute. The value provided
as a StringRefParameter can always be emitted as is. In consquence the
constant and variable ops explicitly need to opaque attributes which are
no longer typed attributes.
Co-authored-by: Simon Camphausen <simon.camphausen@iml.fraunhofer.de>
Reviewed By: Mogball, jpienaar
Differential Revision: https://reviews.llvm.org/D131666
This adds a variable op, emitted as C/C++ locale variable, which can be
used if the `emitc.constant` op is not sufficient.
As an example, the canonicalization pass would transform
```mlir
%0 = "emitc.constant"() {value = 0 : i32} : () -> i32
%1 = "emitc.constant"() {value = 0 : i32} : () -> i32
%2 = emitc.apply "&"(%0) : (i32) -> !emitc.ptr<i32>
%3 = emitc.apply "&"(%1) : (i32) -> !emitc.ptr<i32>
emitc.call "write"(%2, %3) : (!emitc.ptr<i32>, !emitc.ptr<i32>) -> ()
```
into
```mlir
%0 = "emitc.constant"() {value = 0 : i32} : () -> i32
%1 = emitc.apply "&"(%0) : (i32) -> !emitc.ptr<i32>
%2 = emitc.apply "&"(%0) : (i32) -> !emitc.ptr<i32>
emitc.call "write"(%1, %2) : (!emitc.ptr<i32>, !emitc.ptr<i32>) -> ()
```
resulting in pointer aliasing, as %1 and %2 point to the same address.
In such a case, the `emitc.variable` operation can be used instead.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D120098
