In V3Active, we try hard to turn `always @(a or b or c)` into an
`always_comb` if the only variables read in the block are also in the
sensitivity list. In addition, also allow this optimization when reading
variables that are not in the sensitivity list, but are known to be
constant/never changing after initialization. In particular lookup
tables introduced by V3Table are covered by this. This can have a
significant impact on designs that use the `always @(a or b or c)` style
for combinational logic.
The cost of an AstCMethodHard right now is generally unknown. However,
VlTriggerVec::at is used a lot in conditions, so we make an effort
to estimate this correctly via 2 changes:
- In general when an AstVarRef appears as the target of an
AstCMethodHard, we cost it as a simple address computation (an add)
- Check for VlTriggerVec::at explicitly when costing AstCMethodHard,
which is essentially a load.
This can have a significant effect when there are a lot of unique
triggers in the design.
In non-static contexts like class objects or stack frames, the use of
global trigger evaluation is not feasible. The concept of dynamic
triggers allows for trigger evaluation in such cases. These triggers are
simply local variables, and coroutines are themselves responsible for
evaluating them. They await the global dynamic trigger scheduler object,
which is responsible for resuming them during the trigger evaluation
step in the 'act' eval region. Once the trigger is set, they await the
dynamic trigger scheduler once again, and then get resumed during the
resumption step in the 'act' eval region.
Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
This changeset brings support for accesses like:
class Cls#(type TYPE1);
TYPE1::some_method();
endclass
It is done by delaying dot resolution on type parameters until they get
resolved by V3Param, and doing a more thorough reference skip.
In DFG DfgVertex::width() is only defined for vertices representing
packed values, which DfgVertex::hash() used to violate. The only
non-packed values at the moment are DfgVarArray, which is a
DfgVertexVar, which are handled specially anyway, so this is easy to
fix.
Fixes#3682
In order to not leak signal names with --protect-ids, we simply make the
trigger dump function empty (this is a debug only construct).
Partial fix for #3689
The emitted SystemC types (e.g. sc_bv) are not interchangeable with
Verilator internal C++ types (e.g.: VlWide), so the variables themselves
are not interchangeable (but can be assigned to/from each other). We can
preserve correctness simply be not inlining any SystemC variables (i.e.:
don't simplify any 'sc = nonSc' or 'nonSc = sc' assignments). SystemC
types only appear at top level ports so this should have no significant
impact.
Fixes#3688
