Check that constructor chaining for various corner cases of mixing implicit
and explicit constructors are handled correctly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently when neither an explicit constructor is specified nor any
properties are present in the class that will create an implicit
constructor there will be no constructor for the class.
As a result a class that specifies the arguments for the base class
constructor as part of the `extends` clause will not have the base
constructor called with the right arguments.
E.g.
```
class C;
function new(int a);
endfunction
endclass
class D extends C(10);
endclass
```
To avoid this make sure that an implicit constructor is created when
passing arguments through the `extends` clause.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are some corner cases around class constructor chaining that can
result in chained constructors not being called, or being called multiple
times.
This is primarily related to that a class can have either an explicit
constructor called `new` and an implicit constructor called `new@` and how
the lookup of them is done.
Lookup is currently done independently for the implicit and explicit
constructor using the `method_from_name()` method. `method_from_name()`
will search the whole class hierarchy for a class method. If a class
doesn't have a method by that name it will look in the parent class and so
on.
As a result the lookup for the explicit constructor can return the explicit
constructor of a parent class if the class itself only has an implicit
constructor and vice versa.
E.g. in the following example the constructor of D will not be called
because the implicit constructor for C is found when looking for a implicit
constructor in D.
```
class C;
int x = 10;
endclass
class D extends C;
function new;
$display("D");
endfunction
endclass
class E extends D;
int y;
function new;
y = 20;
endfunction
endclass
E e = new;
```
There is a similar case where the constructor of a base class can be called
multiple times if the base class has an explicit constructor and the
derived class has an implicit constructor. In that case the derived class
constructor will call the base class constructor, but the code that is
emitted for the `new` statement will call both of them.
To mitigate this introduce a new method to lookup the constructor that will
search for either the explicit or implicit constructor in the current class
and only continue to search in the base class if neither is found.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Commit 3daa2982ac ("Add support for `const` variables") added support for
constant variables, but had a small mistake and did propagate the constant
flag from the parser if the variable is declared with the `var` keyword.
Still allowing to modify those variables. Fix this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Automatic 2-state vectors currently get initialized to 'hx, while their
default value should be 0.
Make sure the vector is initialized to 0 at the beginning of the automatic
context.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows to declare const variables. These variables are
read-only and can not be assigned a value after their declaration. It is
only possible to assign an initial value as an initializer.
E.g.
```
const int x = 10;
x = 20; // Error
```
The LRM requires that for variable declarations with static storage the
initializer is a constant expression with the extension that other const
variables are also allowed. const variables with automatic storage can
be initialized by any expression.
Checking if an expression contains only const variables requires a bit more
work to implement. So for now be more lenient that what the standard
requires and allow arbitrary expressions to initialize const variables even
for those with static storage.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
arith_expr_type() queries the expression type of its two child nodes up to two
times. Since the child nodes might also need to query their child nodes
expression type to determine their own this can lead to an exponential runtime.
For complex expressions this can easily result in very long elaboration time.
Avoid this by querying the expression type only once for each child node.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Check that it is possible to declare module ports with only partial
attributes. Other attributes should be inherited from the previous port in
the list or use the default.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
In Verilog it is possible to declare multiple ports as part of the same
port declaration. Ports declared this way all have same direction, signal
kind and data type. E.g.
```
module M (input [3:0] a, b, c) ...
```
SystemVerilog extends this and allows to override on a per port basis
certain port attributes. E.g. redefine just the data type
```
module test (input [3:0] a, [1:0] b, int c) ...
```
Or to just redefine the port kind
```
module test(input [3:0] a, var b, wire c) ...
```
It is even possible to leave out the direction for the very first port. As
long as at least one other property of the port is specified. In that case
the direction will default to `inout`. E.g.
```
module test(integer a, b, c) ...
```
Furthermore it is possible to specify unpacked dimensions for each of the
ports. E.g.
```
module test(input integer a, b[1:0], c[3:0][1:0]) ...
```
If all port properties are omitted for the first port this indicates the
start of a non-ANSI port list.
Extend the parser to handle this.
If all three direction, port kind and data type are omitted they are
inherited from the previous port. Otherwise
* If the direction is omitted it is inherited from the previous port.
* If the data type is omitted it defaults to logic.
* If the port kind is omitted the behavior depends on the direction.
For output ports with an explicit data type it is a variable, for
all others it is a net.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Add a helper function to the parser that handles module port declaration.
This allows to reduce a bit of duplicated code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
`$bits()` for array types is supposed to return the full size of the array
in bits. This currently works for data types that are passed to `$bits()`,
but not for array typed identifiers.
E.g.
```
typedef int T[1:0];
T x;
$display($bits(T)); // -> 64
$display(x); // -> 32
```
Since the `$bits()` implementation uses the expr_width of an expression
include the size of the unpacked dimensions in that for array identifiers
and array slices. Strictly speaking an array identifier does not have an
expression width, but this would be its expression with if it were for
example bitstream cast to a vector.
Special care needs to be take to not trying to pad array identifier
expressions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Bit selects on packed arrays are always unsigned and have a width of 1.
Element selects on a multi-dimensional packed array are always unsigned and
have the width of the element.
At the moment a element or bit select on the last level element of a
multi-dimensional signed array will incorrectly yield a signed expression.
Commit 40b36337e2 ("Fix some bugs with packed array dimensions") added
some special checks to fix the width on multi-dimensional array element
selects. But this removed the unsigned attribute from bit selects.
Commit 81947edaa5 ("A bit select is not the same as selecting part of a
packed array") fixed this for single dimensional packed array, but left it
broken for multi-dimensional arrays.
Commit 7c024d6cab ("Fix width calculation for bit/part selects of
multi-dimensioned packed arrays.") added some additional fixes for the
width calculation, which make the special checks in the first commit
unnecessary.
We can now remove those checks which will give us the correct behavior in
terms of the signedness of bit and element selects on both single- and
multi-dimensional packed arrays.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
At the moment there are two rules for port declarations. One that allows
the port to be declared as an unpacked array, the other that allows to
specify an initializer expression.
SystemVerilog allows both to be specified in the same port declaration. Add
support for this to the parser.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The module_output_port_list_def declares a output port with an implicit
data type and assigns an initial value to it. Since output ports with an
implicit data type are nets this test is not standard compliant.
This only works because at the moment the parser incorrectly flags all
output ports with an initial value as variables rather than following the
method defined by the standard to decide whether the port should be a net
or variable.
Make the test standard compliant by using an explicit data type for the
output port, in which case it will be a variable.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The currently used checkout@v2 CI action shows the following deprecation
warning
```
Node.js 12 actions are deprecated. Please update the following actions to
use Node.js 16: actions/checkout@v2. For more information see:
https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.
```
Github has announced that this will eventually stop working somewhen in mid
2023.
Switch to checkout@v3 which uses Node.js 16 to avoid the ci from breaking
in the near future.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen
Cary R
Stephen Williams
mole99