SystemVerilog allows tasks, functions, and classes to be defined at the
root level or inside packages, so we can't rely on an enclosing module
being present to provide the timescale.
(cherry picked from commit 7bed181f68)
If a static variable declared in a task, function, or block has an
initialisation expression, SystemVerilog requires the declaration to
have an explicit static lifetime. This is supposed to be a compile
error, but for now just output a warning.
Implementing this required adding support in the parser for explicit
lifetimes in variable declarations. For now, just output an error if
the user asks for a lifetime that isn't the default for that scope.
(cherry picked from commit 9538c81d34)
There were also some subtleties related to using enumerations
from typedefs and using them in multiple places. Fix various
bugs related to those issues.
This was temporarily implemented to just copy definitions to the
local scope, but the better method is to create a PEIdent that has
the package attached to it.
Class methods belong in a class scope, not the containing module.
So create a lexical scope that carries tasks and functions and
create a PClass to represent classes.
This gets me to the point where the parser stashes a defined type,
and the lexical analyzer uses the type names to differentiate
IDENTIFIER and TYPE_IDENTIFIER.
The pform propagates the parsed enum base type information
to the elaborator so that the base type can be fully elaborated.
This is necessary to get the types of the enumeration literals
correct.
When enum names are used as r-values in expressions, use their
values. Treat the enum names similar to (but not exactly as)
localparams so that they fit into the rest of the elaboration
flow naturally.
Creation of implicit nets requires knowledge of whether an identifier
has been declared before it is used. Currently implicit nets are
created during elaboration, but by this stage the order of declaration
and use is not known. This patch moves the creation of implicit nets
into the parser stage.
Currently, parameters and localparams declared in tasks, functions,
generate blocks, and named blocks are placed in the parent module
scope. Event declarations in these scopes are not permitted (a
syntax error is reported). This patch corrects this behaviour, so
that all the above declarations are accepted and are placed in the
scope in which they are declared.
Note that the IEEE standard does not permit parameter declarations
in generate blocks. This patch causes the parser to reject such
declarations.
Within generate schemes it is possible to have nested scopes, even
more liberally then outside generate blocks. So see to it that the
scopes properly stack with the generate blocks, and that wires and
behaviors are put in the right scopes.
Named begin/end blocks burried within generate schemes need to be
elaborated. Handle this by remembering to elaborate_scope on the
statements within the generate scheme.
In the process, clean up/regularize some of the member names and
methods.
Normally processes are found in the lexical scope of a module, but
there are special cases where processes (other then task/function
definitions) are in other lexical scopes. The most likely case is
initilizations that are in the lexical scope where the assigned
variable is declared.
In the process, the behaviors list is kept in the base PScope class
instead of the Module or any other derived lexical scope class.
Move the storage of wires (signals) out of the Module class into
the PScope base class, and instead of putting the PWires all into
the Module object, distribute them into the various lexical scopes
(derived from PScope) so that the wire names do not need to carry
scope information.
This required some rewiring of elaboration of signals, and rewriting
of lexical scope handling.
All the pform objects that represent lexical scope now are derived
from the PScope class, and are kept in a lexical_scope table so that
the scope can be managed.
Modules, functions and tasks are named scopes so derive them all
from the PScope base class. These items all take scoped items, so
the eventual plan is to move these items into PScope.
Martin Whitaker
Cary R
Stephen Williams
Arun Persaud
Martin Whitaker