Standard attribute names and target names in both forms of the Icarus
`$attribute` extension are unambiguous identifier positions. When such a name
matches a visible typedef the lexer returns `TYPE_IDENTIFIER`, while the
grammar only accepts `IDENTIFIER`.
Use `identifier_name` for all of these positions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The LRM allows omitting the `parameter` keyword in a module parameter port
list, but the optional type in that form is a data_type, not an implicit
data type. A parameter port list like this is therefore invalid:
module M #([3:0] P = 1);
The parameter declaration grammar was reusing the general
value_parameter_assign_with_type rule for the omitted-keyword form. That rule
also accepts implicit types so that ordinary `parameter signed P = 1`
declarations work, which made the omitted-keyword form accept implicit types
as well.
Add a separate rule for value parameter assignments without the `parameter`
keyword. The rule still accepts bare identifiers and explicit data types so a
parameter name can shadow a visible typedef name, but it rejects implicit
types.
Fixes: e56c93a2be ("Support shadowing type identifiers in parameter declarations")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
A named binding selector such as `.T(expr)` names an existing formal port,
parameter, task or function argument, or constructor argument. It is not a
declaration of a new identifier. If a visible typedef named `T` exists at the
use site the lexer returns `TYPE_IDENTIFIER`, which made the parser reject the
binding selector.
Modport simple port aliases use the same grammar, but are slightly different:
the selector is the modport-visible port name and can shadow a visible typedef
name in the interface scope.
Use `identifier_name` for the selector name in `named_expression` and
`named_expression_opt`. This covers named parameter overrides, named task and
function arguments, named constructor arguments, and modport simple port
aliases. Also use `identifier_name` in the named module port connection rules,
including implicit named port connections and error recovery.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a declaration in an inner scope to use the same name as a
type identifier from an outer scope. This also applies to named event
declarations. The lexer reports such names as `TYPE_IDENTIFIER` before the
event has been installed, which made constructs such as:
typedef int T;
module test;
event T;
endmodule
fail in the event declaration grammar.
Event declarations do not have the local type/name ambiguity that exists for
variable, net, or parameter declarations. The name in `event_variable` is
always the event name. Use `identifier_name` so a `TYPE_IDENTIFIER` token can
be accepted as the event name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a named block label in an inner scope to use the same
name as a visible type identifier from an outer scope. The lexer reports such
names as `TYPE_IDENTIFIER` before the label has been installed, which made
constructs such as:
typedef int T;
module test;
initial begin
begin : T
end : T
end
endmodule
fail in the block label grammar.
The affected grammar positions are label names, not declarations with an
adjacent type/name ambiguity. Use `identifier_name` for `label_opt` and for the
anachronistic named generate begin form so a token returned as `TYPE_IDENTIFIER`
can still be accepted as the label name. With `label_opt` able to handle
`TYPE_IDENTIFIER`, the separate class end-label rule is no longer needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a package declaration to use a name that is also visible
as a type identifier. The lexer reports such names as `TYPE_IDENTIFIER` before
the package has been installed, which made constructs such as:
package p;
typedef int T;
endpackage
import p::*;
package T;
endpackage
fail in the package declaration grammar.
Package declarations do not have the local type/name ambiguity that exists for
variable, net, or parameter declarations. After the optional lifetime the next
token is always the package name. Use `identifier_name` so a
`TYPE_IDENTIFIER` token can be accepted as the package name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The parameter declaration grammar allows a visible type identifier to be used
as a parameter name. The assignment continuation rule still used
`identifier_name`, which made Bison reduce a `TYPE_IDENTIFIER` before it had
seen whether following dimensions belonged to the parameter name or to an
explicit type identifier.
Match ordinary and type identifiers directly in `parameter_assign` so the
parser can shift dimensions before deciding between a parameter name and an
explicit parameter type.
Fixes: e56c93a2be ("Support shadowing type identifiers in parameter declarations")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a UDP primitive or UDP port declaration to use the same
name as a visible type identifier from another namespace or outer scope. The
lexer reports such names as `TYPE_IDENTIFIER` before the UDP name has been
installed, which made constructs such as:
typedef int T;
primitive T (Q, A);
output Q;
input A;
table
0 : 0;
endtable
endprimitive
fail in the UDP grammar.
UDP primitive and port names do not have the local type/name ambiguity that
exists for variable, net, or parameter declarations. Use `identifier_name` for
the primitive name, the UDP port list, UDP port declarations, and the UDP
initial target so a `TYPE_IDENTIFIER` token can be accepted as the UDP name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a declaration in an inner scope to use the same name as a
type identifier from an outer scope. This also applies to enum item names. The
lexer reports such names as `TYPE_IDENTIFIER` before the enum item has been
installed, which made constructs such as:
typedef int T;
module test;
enum { T = 1 } e;
endmodule
fail in the enum item grammar.
Enum item declarations do not have the local type/name ambiguity that exists for
variable, net, or parameter declarations. The name in each `enum_name`
production is always the enum item name, including the sequence forms like
`T[2]` and `T[1:2]`. Use `identifier_name` for these names so they can shadow a
visible type identifier.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a declaration in an inner scope to use the same name as a
type identifier from an outer scope. This also applies to task and function
names. The lexer reports such names as `TYPE_IDENTIFIER` before the new task or
function has been installed, which made constructs such as:
typedef int T;
module test;
function int T(input int value);
return value;
endfunction
task T;
endtask
endmodule
fail in the task and function declaration grammar. A class method with the same
name as the class itself hits the same problem because the class name is visible
as a type identifier in the class scope.
The task grammar can accept `identifier_name` directly, because a task has no
return type and the token after `task` and the optional lifetime is always the
task name.
Function declarations have a local return-type/name ambiguity. After
`function T` the parser does not know yet whether `T` is the function name with
no explicit return type, or whether a following identifier will make `T` the
explicit return type as in `function T f`. Parse the optional function return
type and function name together. This allows a `TYPE_IDENTIFIER` token to be
interpreted as the function name when no separate function name follows, while
still parsing typed forms and `void` return types correctly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a visible type identifier to be shadowed by a
parameter declaration name. Parameter declarations still required the
parameter name to be an `IDENTIFIER` token and rejected declarations like:
typedef int P;
module test;
parameter int P = 1;
endmodule
The parameter grammar can not just accept `TYPE_IDENTIFIER` in every name
position. After `parameter P` the parser does not know yet whether `P` is
the parameter name, or whether a following identifier will make `P` the
parameter type.
Parse the optional value parameter type and the first parameter assignment
together. This allows a `TYPE_IDENTIFIER` token to be interpreted as the
parameter name when no explicit type is present, while still parsing a
following identifier as the parameter name for typed parameters.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a class property to have the same name as a visible
type. The lexer reports the visible type name as `TYPE_IDENTIFIER` before
the property has been installed, which made constructs such as
`typedef int T; class C; int T; endclass` fail in the class item grammar.
A class property with the same name as the class itself hits the same
problem. Member references such as `obj.T` or `obj.C` can also hit the
same tokenization problem in hierarchical names.
Parse class properties through the same declaration helper used for
variables so the first type/name pair can be disambiguated. Also let
hierarchical member names use `identifier_name`.
Stop type lookup when a class scope already has a property with the same
name. This makes method body references resolve as properties instead of
visible types, including type names found through wildcard imports.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows a declaration in an inner scope to use the same name as a
type identifier from an outer scope. The lexer reports such names as
`TYPE_IDENTIFIER` before the new declaration has been installed, which made
constructs such as `int T;`, `wire T;`, and `input T` fail when `T` was a
visible typedef.
The affected declaration forms have a local type/name/dimension ambiguity. For
example, after `input T` or `wire T` the parser does not know whether `T` is the
declared name, or whether a following identifier will make `T` the declaration
type in `input T x` or `wire T x`. With dimensions, `input T [1:0]` and
`wire T [1:0]` can be either a declaration named `T` with unpacked dimensions or
a declaration using typedef `T` as a packed type followed by another name.
Parse these declaration forms with productions that decide the first declarator
and carry the selected declaration type across the rest of the list. This covers
variable declarations, net declarations, ANSI and non-ANSI module port
declarations, and task/function port declarations. Other identifier uses still
need separate grammar changes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows an identifier that is visible as a typedef to be
shadowed by a declaration in a nested scope or reused as a declaration
name in another namespace. The lexer can return `TYPE_IDENTIFIER` before
the new name has been installed, so these grammar positions reject
otherwise valid code.
This is not a complete conversion of all identifier grammar sites. Only
handle the trivial conflict-free cases where `IDENTIFIER` can be replaced
by `identifier_name` without any surrounding grammar changes.
Also stop type lookup when the current scope already has a local symbol
with the same name. This makes later references to a shadowing
declaration use the local symbol instead of an outer typedef.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows initialized and uninitialized net declaration entries to
be mixed in the same declaration, e.g. `wire x, y = 1'b1`. In Verilog,
either all nets need to have an initializer or non can have one.
In addition SystemVerilog also allows assignments to arrays of wires during
declaration. E.g. `wire a[3:0] = b;`
Currently there are two different rules for net declarations, one for each
of the Verilog variants. Combine these into a single rule to support
SystemVerilog mixed declarations as well as the assignment to array nets.
When running in Verilog mode still reject mixed initialized and
uninitialized with a check after the parsing.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog 2023 allows type parameters to be restricted to a
specific kind of type, e.g. `parameter type struct T = T0`.
This is very similar to the type restrictions that can be applied to
forward typedefs.
Factor the support code from the typedefs into a standalone helper and
reuse it for both.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog 2023 adds soft packed unions. They are pretty much the same
as regular packed unions except they remove the restriction that all
elements have to have the same packed width.
The packed with of the union itself is the maximum packed width of any
element.
The bits of each member are right-justified towards the LSBs and this
representation is applied recursively to nested soft packed unions. The
existing packed union member offsets already use that layout. When
accessing a field that is smaller than the union itself upper bits are
ignored for both reading and writing.
The `soft` qualifier implies a packed union so both `union soft U { ... }`
and `union soft packed U { ... }` declare a soft packed union.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The parser union still has a few fields that are not used by any
grammar rule. They do not have matching semantic type tags and no
action references them.
Remove the unused fields.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The LRM allows to add a lifetime specified for variables declared in
package scope. It is not particular useful since only static lifetime is
allowed. But it is legal syntax, so support it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The drive strength of a net must be declared between the net type and the data type. E.g.
wire (weak0, strong1) [7:0] x;
The current implementation expects the drive strength after the data type. Update the parser to fix this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
As discussed in issue #1143, the for loop initialisation statement,
termination condition, and step statement were only made optional in
IEEE 1800-2012. So check all three are present when compiling for
ealier generations.
SystemVerilog makes all of the initialisation, condition, and step
components of a for loop optional. We already support this for the
initialisation and step components.
Enhance the lists of identifiers and declaration assignments generated
by the parser to associate each identifier with its lexical_pos. Also do
this for single items in complex parser rules where the location passed
to the pform is not the location of the identifier.
This is needed for detecting use before declaration. The lexical scanner
is the only place where we process the source text in strict lexical
order, so do it there.
As Verilog allows modules to span multiple source files, don't reset
the counter when we reset the lexor.
In addition to providing positional arguments for task and functions
SystemVerilog allows to bind arguments by name. This is similar to how
module ports can be bound by name.
```
task t(int a, int b); ... endtask
...
t(.b(1), .a(2));
```
Extend the parser and elaboration stage to be able to handle this. During
elaboration the named argument list is transformed into a purely positional
list so that later stages like synthesis do not have to care about the
names.
For system functions and tasks all arguments must be unnamed, otherwise an
error will be reported.
In addition to functions and tasks arguments can also be bound by name for
the various different ways of invoking a class constructor.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen
Cary R.
Jose Tejada
Martin Whitaker