For loops may have empty initialization statements. In that case some things
can't be done, such as loop unrolling or synthesis, but otherwise it is a
valid thing to do. So generate the correct code in this case.
SystemVerilog allows to skip dimensions in a foreach loop by not specifying
an identifier name for the dimensions. E.g. the following will iterate over
the first and last dimensions, but skip the middle dimension.
```
int x[1][2][3];
foreach(x[a,,b]) ...
```
Add support for this to the parser as well as elaboration.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog supports type parameters. These are similar to value
parameters, but they allow to pass a type to a module or similar when
instantiating it.
E.g.
```
module A #(parameter type T = int);
endmodule
module B;
A #(.T(real)) i_a;
endmodule
```
Add support for handling type parameters.
For the vlog95 and vhdl backends type parameters, similar to typedefs, get
replaced with their actual value. For modules with non-local type
parameters for each module instance a unique module or architecture is
generated with the actual type.
Querying type parameters through VPI is not yet supported.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog supports forward type declarations. This allows to declare a
type identifier and use it, e.g. in a signal declaration, before declaring
what the actual type is. The type still needs to be fully defined
eventually in the same scope as its forward type declaration. E.g.
```
typedef T;
T x;
typedef int T;
```
The forward type definition can also contain the kind of the type it is
going to be. E.g struct, union, class, etc. The LRM calls this the basic
type. If the actual type is not of the basic type specified in the forward
type declaration this is an error. E.g.
```
typedef struct T;
typedef int T; // Error, int is not a struct
```
It is legal to have more than one forward type declaration for the same
type name, as long as the basic type is the compatible. It is even legal to
have a forward type declaration after the actual type has already been
declared. E.g.
```
typedef T;
typedef int T;
typedef T;
```
Implement support for forward type definitions as part of the new
typedef_t. The basic type will be attached to the typedef_t.
The compatibility of the basic type for multiple forward type declarations
will be checked in the parser. The compatibility of the basic type to the
actual type will be checked during elaboration, once the actual type is
known.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently typedefs are just a pointer to a data_type_t.
Currently typedefs are implemented by setting the name field of a
data_type_t when a typedef of the type is declared. This works mostly, but
there are some corner cases that can't be supported.
E.g. a typedef of a typedef does not work as it overwrites the name field
of the same data_type_t multiple times.
Forward typedefs can also not be supported since forward typedefs allow to
reference a type before it has been declared.
There are also some problems with type identifier references from a
higher-level scope if there is a type identifier in the current scope with
the same name, but it is declared after the type identifier has been
referenced. E.g. in the following x should be a vector fo width 8, but it
will be a vector of width 4, because while the right type is used it is
elaborated in the wrong scope.
```
localparam A = 8;
typedef logic [A-1:0] T;
module M;
localparam A = 4;
T x;
typedef int T;
endmodule
```
Furthermore typedefs used for the type of ports are elaborated in the wrong
scope.
To handle these corner case issues introduce a data_type_t for typedefs.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog supports using compressed assignment operators for the genvar
for loop variable update.
Add support for this in a similar way as increment/decrement operators by
transforming the statement to its uncompressed equivalent. E.g. `x += y`
gets transformed to `x = x + y`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently when referencing a typedef this gets replaced with the
`data_type_t` that the typedef points to. This works for most cases, but
there are some corner cases where it breaks down.
E.g. it is possible to have a scoped type identifier which references a
type defined in a package. For such type identifiers, only the data_type_t
itself is remembered, but not the package scope. This will cause the type
identifier to be elaborated in the wrong scope.
Furthermore type identifiers of vector types used for module or task port
might not be elaborated in the correct scope.
Introduce a new `typeref_t` which has `data_type_t` as a base type and can
be used as the data type for a signal. A new instance of a `typeref_t` is
created when referencing a type identifier. The `typeref_t` remembers both
the data type and the scope of the type identifier.
When elaborating the `typeref_t` the elaboration is passed through to the
referenced `data_type_t`. But special care is taken to lookup the right
scope first.
With the new approach also typedefs of typedefs are supported. This
previously did not work because chained typedefs all reference the same
`data_type_t`, but each typedef sets the `name` field of the `data_type_t`.
So the second typedef overwrites the first typedef and a lookup of the
scope of the first typedef by name will fail as it will return the scope of
the second typedef.
This refactoring also allows to define clear ownership of a data_type_t
instance. This e.g. means that an array type owns its base type and the
base type can be freed when the array type itself is freed. The same is
true for signals and class properties, they now own their data type and the
data type can be freed when the signal or property is freed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The current class end label parser rule gets the data type from the
TYPE_IDENTIFIER, casts that to a class_type_t and gets the name from that.
This code was written when the TYPE_IDENTIFIER only provided the data type.
But these days it provides both the data type and the name. Simplify the
code to get the name directly from the TYPE_IDENTIIFER.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
In order to avoid conflicts in the grammar the lexer distinguishes between
identifiers and type identifiers. To correctly classify an identifier the
lexer needs to know in which scope a token is parsed. E.g. when the parser
encounters a package scope operator it calls `lex_in_package_scope()` to tell
the lexer which scope the following identifier should be classified in.
Currently the `lex_in_package_scope()` is only used when a type identifiers
is parsed, but on for normal identifiers. As a result it is not possible to
reference variables or function from a package scope that have the same
name as a type identifier in the current scope. E.g.
```
package P;
int T;
endpackage
module test;
typedef int T;
initial $display(P::T);
endmodule
```
Another problem is that in expressions both type identifiers and signal
identifiers can be referenced. As a result there are two rules in an
expression that can be reduced
* <PACKAGE_TYPE> :: <TYPE_IDENTIFIER>
* <PACKAGE_TYPE> :: <IDENTIFIER>
The way the rules are formulated at the moment the parser has to use token
lookahead to decide which rule to follow before it can reduce the package
scope operator. As a result the lexer detects the token before
lex_in_package_scope() is called and the identifier does not get evaluated
in the package scope, but in the current scope. Which can cause the
identifier to be misclassified. E.g.
```
package P;
typedef int T;
shortint X;
endpackage
module test;
typedef byte X;
initial $display($bits(P::T));
initial $display($bits(P::X));
endmodule
```
Here `P::T` gets classified as a signal identifier and `P::X` gets
classified as a type identifier.
To solve this introduce a common rule for the package scope operator. Using
the same rule everywhere allows the parser to reduce it unconditionally
without using lookahead.
Note that there are additional problems with resolving the type of a scoped
type identifiers in expressions, but this is a prerequisite to solve that.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The parser currently only allows package scoped functions to be called if
there is at least one argument. But package scoped functions are the same
as normal functions and it is allowed to call them with no arguments. It is
even possible to pass no value for a positional argument, if the positional
argument has a default value.
Update the parser to handle this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
For function calls when calling the PECallFunction() constructor a copy is
made of the argument expression list. This means the original list should
be deleted within the rule.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
If the type of a port is an array type it currently always gets evaluated
in the scope where the port is declared.
But if the type is a typedef it might be declared in a different scope and
must be evaluated in that scope. E.g. the following will declare an array
port with 10 entries and an element type of a 5 bit vector, while it should
declare one with 4 entries and an element type of a 2 bit vector.
```
localparam A = 2;
localparam B = 4;
typedef [A-1:0] T[B];
module test (
T x
);
localparam A = 5;
localparam B = 10;
endmodule
```
This is in part due to array types being given special handling. This was
necessary before because each base type required slightly different
handling and so the base type had to be extracted from the array type.
This has now been consolidated and all data types are treated the same.
The only exception is the vector type which still needs special handling to
support separate definition of port direction and type.
As a result it is possible to remove the special handling of the array
type. This solves the problem of evaluating the type in the wrong scope.
Some special handling needs to be retained though to be able to
differentiate between array dimensions that are part of a type and array
dimensions that are part of port declaration. This is again necessary to
correctly support separate definition of port direction and type. E.g. in
the example below port `x` and `y` get treated slightly differently, even
though the resulting signals will be identical.
```
typedef logic [7:0] T[1:0];
...
input T x;
input [7:0] y[1:0];
```
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The parser used to have behavior that was dependent on the
`ivl_variable_type_t` of a signal. It also used the `ivl_variable_type_t`
of a signal to decide whether a signal can be re-declared as part of a
non-ANSI port declaration.
Neither of these is done anymore and most of the reference to
`ivl_variable_type_t` can be removed from the parser. The only thing it is
still needed for is to decide whether a vector type is 4-state or 2-state.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
`pform_make_task_ports()` has code very similar to `pform_set_net_range()`.
Use that helper function instead of duplicating the code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The last user of the `make_range_from_width()` was removed in commit
f6042033d0 ("Correctly handle separate port type declaration for
`integer` and `time`").
Remove the function itself as well.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Both Verilog (2005) and SystemVerilog support default port values for
variable output ports. SystemVerilog also supports default port values for
input ports. For port declaration lists it is possible to specify the
default value for port identifier.
E.g.
```
module M (
input integer x, y = 1,
output integer z, w = 2
) ...
```
Currently the parser only supports specifying the default value for the
first identifier in the list. Extend the parser to also allow to specify
the default value for identifiers in the list.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few places where it is possible to provide an optional
initializer in the form of `[ = <expression> ]`.
There are currently multiple rules that implement this behavior as well as
few places with duplicated rules, one with and one without the initializer.
Introduce a common helper rule for optional initializers. This allows to
remove some duplicated code from the parser.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
For output port lists with a default value for the first port declaration
all subsequent port declarations are declared as inout ports. This is due
to a small typo when setting the `port_declaration_context` port direction.
Fix this to make sure all ports in the port declaration list are declared
as output ports.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog supports sign cast where it is possible to change the
signedness of an expression. Syntactical it is similar to width or type
casting, except that the keywords 'signed' or 'unsigned' are used in front
of the cast operator. E.g.
```
logic [3:0] a = 4'b1000;
logic [7:0] b = signed'(a); // b is 8'b11111000;
logic signed [3:0] c = 4'b1000;
logic signed [7:0] d = unsigned'(c); // d is 8'b00001000;
```
As noted by the LRM section 6.24.1 ("Cast operator") applying a sign cast
to an expression is equivalent to calling the $signed() and $unsigned()
system functions on the expression.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog adds the `var` keyword that can be used to declare a signal
as a variable.
In contexts where a signal is always a variable it is purely optional and
it makes no difference whether it is specified or not. This is in
* for loop variable declarations
* task and function port declarations
For variable declarations as block items when `var` is used it is possible
to omit the explicit data type and use a implicit data type instead. E.g.
all of the following are valid.
```
var x;
var signed y;
var [1:0] z;
```
For module input and output ports the `var` keyword can be used in place of
the net type. It can be combined with either an implicit or explicit data
type.
E.g.
```
input var x
output var [1:0] y
```
inout ports can not be variables and will be reported as an error.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Refactor the variable lifetime parser rules so that instead of having too
rules, one with lifetime and one without, there is a single rule where the
lifetime is an optional element.
This helps to avoid a combinatorial explosion of parser rules once we
add `var` support.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently the parser can recover from `integer` or `time` variable
declarations, but not for variables of other types. Refector the parser
rules so that it can recover for all variable types as well as events.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The custom `svector` class is essentially a subset of `std::vector`. There
is no inherent advantage to using `svector`. Both have the same memory
footprint.
`svector` was designed to be of static size, but there are a few places in
the parser where it has to grow at runtime. Handling this becomes a bit
easier by switching to `std::vector` since it is possible to use its
methods which take care of resizing the vector.
This also allows to remove the unused parameter of the `lgate` struct
constructor, which was only needed for compatibility with `svector`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The lgate struct has its own fields for tracking file and line number,
while everything else that has this information attached inherits from the
LineInfo class.
Make lgate also inherit from LineInfo for consistency.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `pform_set_data_type()` function is used to set the data type as well
as attributes on a list of signals. Currently the signals are passed as a
list of signal names and then the function looks up the actual signals from
the names.
Refactor the code to directly pass a list of signals. This will allow to
skip the look-up by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
`pform_set_reg_idx()` is always called right after `pform_makewire()`. Move
it into the function. This avoids the extra lookup that
`pform_set_reg_idx()` does to get the PWire from the name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few parameters for `pform_makewire()` and related functions
that always get passed the same value.
* port_type is always NetNet::NOT_A_PORT
* attr is always 0
Remove these parameters.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Variable declarations in packages need an explicit data type. Omitting the
data type or using just packed dimensions is not valid syntax. E.g. the
following should not work.
```
package P;
x;
[1:0] y;
endpackage
```
The current implementation does accept this tough. To fix this update the
parser to only allow explicit data types for package variable declarations.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When using non-ANSI style port declarations it is possible to declare the
port direction and the data type for the port in separate statements. E.g.
```
input x;
reg x;
```
When using packed array dimensions they must match for both declarations.
E.g.
```
input [3:0] x;
reg [3:0] x;
```
But this only applies for vector types, i.e. the packed dimension is
explicitly declared. It does not apply to the `integer` and `time` types,
which have an implicit packed dimension.
The current implementation requires that even for `integer` and `time`
types the implicit dimension needs to be explicitly declared in the port
direction. E.g. the following will result in a elaboration error
complaining about a packed dimension mismatch.
```
module test;
output x;
integer x;
endmodule
```
Currently the parser creates a vector_type_t for `time` and `integer`. This
means that e.g. `time` and `reg [63:0]` are indistinguishable during
elaboration, even though they require different behavior.
To fix let the atom2_type_t handle `integer` and `time`. Since it no longer
exclusively handles 2-state types, rename it to atom_type_t.
This also fixes a problem with the vlog95 target unit tests. The vlog95
target translates
```
module test(output integer x);
endmodule
```
to
```
module test(x);
output x;
integer x;
endmodule
```
which then fails when being elaborated again. There were some regression
tests that were failing because of this that will now pass.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
It is possible to call a class method without parenthesis if no arguments
are specified.
At the moment this works when calling a class method by name. But when
using the implicit class handle `this` or `super` it does not work.
Add support for this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Class constructors can be declared without parenthesis after the `new` when
no arguments are required. Just like for normal function.
In a similar way the base class constructor can also be invoked without
parenthesis after the `new`.
```
class C extends D;
function new;
super.new;
endfunction
endclass
```
Add support for this by making the parenthesis optional in the parser.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Class constructors don't allow for non-ANSI ports. E.g. the following is
not valid.
```
class C;
function new();
input int i;
endfunction
endclass
```
The parser will currently accept this, but otherwise ignore the non-ANSI
port. Modify the parser rules so that this is a syntax error.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few places in the grammar that follow the pattern of
`implicit_class_handle '.' hierarchy_identifier` and then splice the two
identifier paths into a single one. Factor this into a common helper rule
to avoid duplicated code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few places in the grammar where it is possible to specify a
argument list in parenthesis or nothing. E.g. a task invocation.
```
task t(int a = 10);
endtask
initial begin
// All 3 are valid syntax
t(1);
t();
t;
end
```
Factor this out into a common rule to be able to remove some duplicated
code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few places in the grammar where it is possible to specify a
task/function port list in parenthesis or nothing. E.g. task and function
prototypes. Factor this out into a common rule to be able to remove some
duplicated code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The base type for an enum type can be a type identifier for a typedef as
long as it resolves to a vector or integer type with at most one packed
dimension. This is described in section 6.19 ("Enumerations") of the LRM
(1800-2017). E.g.
```
typedef bit [3:0] T;
enum T {
A
} e;
```
Add support for this by allowing to specify a type identifier as the base
type for an enum in the parser. During elaboration it is checked whether
the type identifier resolves to a valid enum base type.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
It is possible to declare a new typedef that shadows an existing typedef in
a higher level scope. E.g.
```
typedef int T;
class C;
typedef real T;
endclass
```
In the current implementation this works for scopes that are not class
scopes.
Update the parser to also support this in class scopes by re-using the
existing parser rule that is used for the other scopes.
Reusing the existing rule also adds support for class forward typedes
inside classes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
It is possible to declare a new typedef that shadows an existing typedef in
a higher level scope. E.g.
```
typedef int T;
module M;
typedef real T;
endmodule
```
In the current implementation this only works as long as the new type is
a not an array type.
Update the parser to allow to specify unpacked dimension when overwriting
a typedef from a different scope.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The parser currently expects `reg output` for UDP registered output. But
the correct syntax is `output reg`. Fix this to accept the correct syntax.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently there is a mix of passing line information either as `struct
vlltype` or as a separate `const char *file` and `unsigned lineno`.
For consistency always use the struct vlltype variant.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The SystemVerilog grammar explicitly allows an empty class item
declaration. The empty class item declaration is just a semicolon and has
no effect.
E.g. the following is legal
```
class C
int x;;;
endclass
```
Add support to the parser to accept empty class item declarations.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
In Verilog module input ports can only have a packed dimensions and a
signed flag, but no explicit data type.
In SystemVerilog an explicit data type can be specified for module input
ports. Such a port is a net, regardless of the data type, unless
explicitly made a variable using the `var` keyword.
This works for the most part in the current implementation, but for some
data types such as `reg` and `integer` the input port is turned into a
variable. And since input port's can't be variables in the current
implementation this results in an error.
Fix this by completely removing the `reg_flag` that is used to indicate
that a certain data type is always a variable. There is no such restriction
on data types for SystemVerilog and for Verilog there are already checks in
place that a input port can only have an implicit (or real) data type.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
While a variable can have any data type the data type for nets is quite
restricted.
The SystemVerilog LRM section 6.7.1 ("Net declarations with built-in net
types") requires that the data type of a wire is either a 4-state packed or
a unpacked struct or unpacked array of 4-state packed types.
As an extension to this iverilog allows real data type for wires as well as
2-state packed types.
Add a check that reports an error if a net with any other type is declared.
In addition in Verilog a net can not have an explicit data type at all. It
can only have a packed dimension and a signed flag. As an extension to this
Icarus also allows wires to be of `real` data type.
Note that in Verilog mode the data type is checked in the parser since only
the parser knows whether the data type is an implicit type (`input reg
[7:0]` and `input [7:0] x` elaborate the same). But for SystemVerilog the
type is checked during elaboration since due to forward typedefs and type
parameters the type is not necessarily known in the parser.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
In SystemVerilog output ports are a variable if either:
* They are explicitly declared a variable (with the `var` keyword)
* There is no explicit net type, but a explicit data type
This is in detail described in section 23.2.2.3 ("Rules for determining port
kind, data type, and direction") of the LRM (1800-2017).
E.g.
```
output x // Net
output [1:0] x // Net
output signed x // Net
output wire x // Net
output wire logic x // Net
output var x // Variable
output logic x // Variable
output var logic x // Variable
output int x // Variable
output real x // Variable
output string x // Variable
output some_typedef x // Variable
```
At the moment the code checks for certain data types and only makes the
output port a variable for those. And it is even different data types
depending on whether the port is declared ANSI or non-ANSI style.
Change this so that if a data type is specified and it is not a implicit
data type (i.e. only ranges or `signed`) then the output is of type
variable.
This ensures consistent and correct behavior.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Task and function item rules are identical. Consolidate them into a single
set of rules to remove some duplicated code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows unpacked array dimensions on non-ANSI style task and
function ports.
To support this refactor pform_make_task_ports() to accept a of
pform_port_t, which in addition to the identifier name also allows to
specify per port unpacked dimensions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tasks and functions support two types of port declarations. Either ANSI
style, in parenthesis after the task name, or non-ANSI style, as
declaration statements in the task body.
In the current implementation SystemVerilog types are only accept for ANSI
style port declarations, while non-ANSI style only accept Verilog types
(reg, integer, time, real).
Add support for SystemVerilog data types for non-ansi style ports.
This also makes the parsing rules simpler since we can use `data_type` to
match all data types and don't need a explicit rule for each supported data
type.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows `parameter` and `localparam` to declare constants
within a class scope. E.g.
```SystemVerilog
class C;
localparam A = 10;
endclass
```
In this context both declare a local parameter that can not be overwritten.
Supporting this can be achieved for the most part by adding a parser
sub-rule in class declaration rule. In addition some extra support code is
needed to mark the parameter as non-overridable.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are currently two rules for parsing variable declarations.
One that is used when declaring variables in as a block declaration item
and another that is use everywhere else.
Consolidate those into a single set of rules. This removes a fair bit of
duplicated code in the parser.
A side effect of this refactoring is that class new statements can be used
as variable initializers as allowed by the standard. E.g.
```
module test;
class C;
endlcass
C c = new C;
endmodule
```
This previously was not supported for block item variable declarations.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Variables don't have a delay or strength and the NetNet::Type is known. Add
a small wrapper around pform_makewire() that can be used to create
variables. This will allow to reduce the boilerplate code for variable
declarations.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few places where pform_makewire() is used and attributes can be
attached to the created net or variable. At the moment pform_makewire()
doesn't allow to specify the attributes, and they either get dropped
silently or with a warning.
Add support for passing the attributes to pform_makewire() which will then
pass it on to pform_set_data_type() to attach it to the declared net or
variable.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are currently two very similar implementations of pform_makewire().
One that takes a `net_decl_assign_t`, the other a `std::list<decl_assignment_t*>`.
The one that takes a `std::list<decl_assignment_t*>` is a superset of the
other. It can handle both wires and variables, while the other can only
handle wires.
Update the parser to generate a `std::list<decl_assignment_t*>` for wire
declarations. This allows to remove one of the two functions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Most things that can be declared in a module can also be declared in a
generate block.
But there are a few exceptions that can not be declared in generate block
* module, program or interface declaration
* specify block or specparam
* timeunit
Some of these currently work while some of them trigger an assertion and
cause and application crash.
Add checks to make sure that all of them these are reported as an error and
do not cause a crash.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The "->" operator is rarely used, but exists. Unfortunately, the syntax
is tied up in a horrible mess with the System Verilog constraint list
syntax. Do some flex magic to make it all work.
SystemVerilog allows to omit the default value of a parameter declared in a
parameter port list. In this case the parameter must be overridden for
every module instance. This is defined in section 6.20.1 ("Parameter
declaration syntax") of the LRM (1800-2017).
In addition a module that has a parameter without a default value does not
qualify for automatic toplevel module selection.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few system functions that take either an expression or a data
type. This is implemented in the parser by allowing a type identifier as a
primary expression.
But those functions allow any data type, not just typedefs. E.g.
```
$bits(int);
$bits(reg [1:0]);
$bits(struct packed { int x; });
```
Support this by changing the parser rule from TYPE_IDENTIFIER to data_type.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows to completely omit the `parameter` keyword in a
module parameter port list. This is described in section 6.20.1 ("Parameter
declaration syntax") of the LRM (1800-2017).
E.g.
```
module a #(X = 10) ...
module b #(int Y = 20) ...
```
It also allows to redefine the parameter type without having to have a
parameter or localparam before the type.
E.g.
```
module a #(parameter int A = 1, real B = 2.0) ...
module b #(int X = 3, real Y = 4.0) ...
```
Extend the parser to support this.
Note that it is not possible to declare a parameter with an implicit data
type this way.
E.g. the following is not legal SystemVerilog
```
module a #([3:0] A = 1) ...
module b #(int X = 2, signed Y = 3.0) ...
```
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When encountering a construct that requires SystemVerilog in most cases an
error message is generated when SystemVerilog is not enabled and parsing
simply continues.
Factor the checking and generating of the error message into a helper
function. This slightly reduces boiler plate code and gives consistent
error messages.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
A base class can be referenced by scope. E.g. if the base class is in a
package.
```
package P;
class B;
endclass
endpackage
module test;
class C extends P::B;
endlcass
endmodule
```
To support this let the parser accept a scope identifier for the base
class.
A small change is also necessary to how the base class lockup is done
during elaboration. At the moment the code will search for the base class
by name in the current scope. This doesn't work with scoped identifiers.
But we already have a reference to the base class data type, so we don't
have to search for it by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are multiple places in the grammar where either a type identifier or
scoped type identifier is accepted.
Factor this into a common parser rule. This removes some duplicated code.
But it will also be required to avoid reduce-reduce conflicts for future
grammar extensions, e.g. to support type parameters.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently when encountering an end label on a unnamed block
a 'syntax error' will be generated and the parser will give up.
Slightly refactor the parser so that this case is detected, a more specific
error message is generated and the parser can recover and continue.
This also slightly reduces the parser since it allows to merge the almost
identical rules for handling named and unnamed blocks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Most named constructs support a end label in SystemVerilog. The handling of
this end label is always the same.
* Generate an error if the end label does not match the name of the block
* Generate an error if not in SystemVerilog mode
* Delete the end label
Factor this into a common helper function. This reduces code size a bit and
results in consistent error messages.
The latter requires refreshing of some gold files to match the slightly
different error messages.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
While it is not a particular useful construct it is legal to have a
parallel block with just variable declarations and no statements. E.g.
```
fork
int x;
join
```
At the moment there is a special rule for completely empty parallel
blocks. Remove that rule and change the statement_or_null_list in the
fork/join parser section to a statement_or_null_list_opt. This way it
covers both completely empty parallel blocks as well as parallel blocks
with only variable declarations.
Note that this already works as expected for named parallel blocks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When declaring module parameters in the ANSI style parameter list it is
possible to omit the `parameter` or `localparam` keyword. In this case
whether the parameter is local or non-local is inherited from the previous
parameter.
In the current implementation when the type of the parameter is not
specified it will always use parameter. E.g. the following will create a
localparam A and a parameter B, while it should be localparam A and B.
```
module #(localparam A = 1, B = 2);
```
Fix this by remembering whether the previous entry was a parameter or
localparam. This is similar to how the parameter data type is already
remembered.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Verilog-AMS defines parameter value ranges which can restrict the value
that can be assigned to a parameter. It defines this for both `parameter`
and `localparam`. Currently it is only implemented for `parameter`. Support
it for `localparam` as well for consistency.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The code for handling parameter and localparameter declarations is very
similar. Consolidate this into a single helper function.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
While it is not a particular useful construct it is legal to have a
begin/end block with just variable declarations and no statements. E.g.
```
begin
int x;
end
```
At the moment there is a special rule for completely empty begin/end
blocks. Remove that rule and change the statement_or_null_list in the
begin/end block parser section to a statement_or_null_list_opt. This way it
covers both completely empty blocks as well as blocks with only variable
declarations.
Note that this already works as expected for named begin/end blocks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
packed structs and packed unions as a whole can either be signed or
unsigned. This information is used when it is used as a primary in an
expression, i.e. without accessing any of the members.
Add support for parsing and elaborating signed structs.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Allow scoped identifiers to be used as the base type for packed array
types. Scoped type identifiers can be used the same way as unscoped type
identifiers.
E.g.
```
package p;
typedef logic [1:0] vector;
endpackage
module test;
p::vector [1:0] pa;
endmodule
```
is a valid construct.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
It is possible to directly declare a packed array of a struct or enum,
without having to typedef the struct or enum first. E.g.
```
struct packed {
int x;
} [1:0] pa;
```
Add support to the parser for handling this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When creating an enum type it must be added to the scope where it is
declared so it can later be elaborated and the enum and its names can be
referenced in expressions.
In addition the names of the enum must be added to the lexor scope so that
name collisions are detected and can be reported as errors.
This is done with pform_put_enum_type_in_scope() function.
At the moment the function is called from two different places
* When adding a typedef of a enum type
* When creating a signal of a enum type
In addition the enum_type_t is added to a class scope `enum_sets` when
declaring a enum property in a class. But this only makes sure that the
enum gets elaborated, its names are not added to the lexor scope.
This works fine for the most part, but breaks for a few corner cases.
E.g. it is possible to declare a enum type as part of the subtype of
another packed type such as structs or packed arrays. E.g.
```
struct packed {
enum {
A
} e;
} s;
```
This is not covered by either of the cases above and neither do the names
of the enum get added to the lexor scope, nor is the enum type elaborated.
Another corner case that is currently not working is declaring a class
property where the type is a typedef of a enum that is declared outside of
the class. In this case the enum is elaborated again inside the class
scope. E.g. the below is supposed to work, but fails with an already
declared symbol error.
```
typedef enum {
A
} e_t;
class C;
typedef enum {
A
} e1;
e_t e2;
endclass
```
In addition since for enums declared in classes they are only added to
`enum_sets`, but names are not added to the lexor scope, it is possible to
declare a different symbol in the class scope with the same name.
E.g. the following elaborates fine
```
class C;
enum {
A
} e;
typedef int A;
endclass
```
To fix this call pform_put_enum_type_in_scope() when the enum_type_t is
created in the parser. This makes sure that it is handled the same
regardless where the type is declared or used.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Refactor the enum rule by adding a enum_base_type rule which handles the
type specific initialization. This allows to keep the non-type specific
parts in a common rule, which makes it easier to modify in future changes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When something goes wrong when parsing a struct member, e.g. the type does
not exist, a nullptr is added to the struct member list. This will cause a
crash when iterating over the list.
E.g.
```
struct packed {
logc x;
} s;
```
Add a check so that nullptr members are not added to the list.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Stephen Williams
Lars-Peter Clausen
Lloyd Parkes
Zachary Snow
Martin Whitaker
Cary R