The _CONST suffix on these macros is only lexical notation, pointer
constness can be preserved by overloading the underlying
implementations appropriately. Given that the compiler will catch
invalid const usage (trying to assign a non-const pointer to a const
pointer variable, etc.), and that the declarations of symbols should
make their constness obvious, I see no reason to keep the _CONST
flavours.
Fail at compile time if the result of these macros can be statically
determined (i.e.: they aways succeed or always fail). Remove unnecessary
casts discovered. No functional change.
VN_AS should be used over VN_CAST in code where the author knows up
front (i.e.: statically) what the true type of the node is. This has
multiple benefits over VN_CAST:
- In the debug build: Asserts node type is as expected
- In the optimized build: It is faster as no superfluous type test
- And (I would argue most importantly) it documents intent in the code
No current instances of VN_CAST changed in this patch
All parameters that are required in the output are now emitted as
'static constexpr, except for string or array of strings parameters,
which are still emitted as 'static const' (required as std::string is
not a literal type, so cannot be constexpr). This simplifies handling
of parameters and supports 'real' parameters.
Other sub-classes of AstNodeCCall do not need the self pointer. Moving
it into the specific sub-class that needs it clarifies V3Descope and
Emit. No functional change intended.
This patch makes OpenTitan verilation with --debug-check 22% faster, and
the same with --debug --no-dump-tree 91% faster. Functionality is the
same (including when VL_LEAK_CHECKS is defined), except V3Broken can now
always find duplicate references via child/next pointers if the target
node is not `maybePointedTo()` (previously this only happened when
compiled with VL_LEAK_CHECKS). The main change relates to storing the
v3Broken traversal state in the AstNode by stealing a byte from what
used to be unused flags. We retain an unordered_set only for marking
pointers as valid to be referenced via a non-child/non-next member
pointer.
The bool AstNode flags fit in a padding gap after m_type. This reduces
memory consumption by about 2% on OpenTitan. Initializing the unused
bits in the flags then avoids a read-modify-write in the constructor
(replacing it with a store constant). Overall verilation speed is about
1% faster.
Remove magic code fragments form EmitCTrace, so Emit need not be aware
that a function is tracing related or not (apart from the purpose of
file name generation). All necessary code is now generated via text
nodes in V3TraceDecl and V3Trace. No functional change intended.
This patch implements #3032. Verilator creates a module representing the
SystemVerilog $root scope (V3LinkLevel::wrapTop). Until now, this was
called the "TOP" module, which also acted as the user instantiated model
class. Syms used to hold a pointer to this root module, but hold
instances of any submodule. This patch renames this root scope module
from "TOP" to "$root", and introduces a separate model class which is
now an interface class. As the root module is no longer the user
interface class, it can now be made an instance of Syms, just like any
other submodule. This allows absolute references into the root module to
avoid an additional pointer indirection resulting in a potential speedup
(about 1.5% on OpenTitan). The model class now also contains all non
design specific generated code (e.g.: eval loops, trace config, etc),
which additionally simplifies Verilator internals.
Please see the updated documentation for the model interface changes.
Teach V3Localize how to localize variables that are used in multiple
functions, if in all functions where they are used, they are always
written in whole before being consumed. This allows a lot more variables
to be localized (+20k variables on OpenTitan - when building without
--trace), and can cause significant performance improvement (OpenTitan
simulates 8.5% - build single threaded and withuot --trace).
These utility classes can be used to hang advanced data structures off
AstNode user*u() pointers, and they take care of memory management for
the client. Use via the call operator().
V3Localize can now localize variable references that reference variables
located in scopes different from the referencing function. This also
means V3Descope has now moved after V3Localize.
The goal of this patch is to move functionality related to constructing
the thread entry points and then invoking them out of V3EmitC (and into
V3Partition). The long term goal being enabling V3EmitC to emit
functions partitioned based on header dependencies. V3EmitC having to
deal with only AstCFunc instances and no other magic will facilitate
this.
In this patch:
- We construct AstCFuncs for each thread entry point in
V3Partition::finalize and move AstMTaskBody nodes under these functions.
- Add the invocation of the threads as text statements within the
AstExecGraph, so they are still invoked where the exec graph is located.
(the entry point functions are still referenced via AstCCall or
AstAddOrCFunc, so lazy declarations of referenced functions are created
automatically).
- Explicitly handle MTask state variables (VlMTaskVertex in
verilated_threads.h) within Verilator, so no need to text bash a lot of
these any more (some text refs still remain but they are all created
next to each other within V3Partition.cpp).
The effect of all this on the emitted code should be nothing but some
identifier/ordering changes. No functional change intended.
This patch introduces the concept of 'loose' methods, which semantically
are methods, but are declared as global functions, and are passed an
explicit 'self' pointer. This enables these methods to be declared
outside the class, only when they are needed, therefore removing the
header dependency. The bulk of the emitted model implementation now uses
loose methods.
astgen now generates ASTGEN_SUPER_* macros, instead of expanding the
ASTGEN_SUPER itself. This means that V3AstNodes.h itself can be included
in V3Ast.h, which helps IDEs (namely CLion) find definitions in
V3AstNodes.h a lot better. Albeit this is a little bit more boilerplate,
writing constructors of Ast nodes should be a lot rarer than trying to
find their definitions, so hopefully this is an improvement overall.
astgen will error if the developer calls the wrong superclass
constructor.
Rework Ast hashing to be stable
Eliminated reliance on pointer values in AstNode hashes in order to make
them stable. This requires moving the sameHash functions into a visitor,
as nodes pointed to via members (and not child nodes) need to be hashed
themselves.
The hashes are now stable (as far as I could test them), and the impact
on verilation time is small enough not to be reliably measurable.
V3Hasher is responsible for computing AstNode hashes, while V3DupFinder
can be used to find duplicate trees based on hashes. Interface of
V3DupFinder simplified somewhat. No functional change intended at this
point, but hash computation might differ in minor details, this however
should have no perceivable effect on output/runtime.
Implements (#2964)
- Remove dead code
- Simplify what is left
- Minor improvements using C++11
- Remove special case AstNode constructors used only in one place in
V3Combine (inlined instead).
No functional changes intended. Boring patch in the hope of being
helpful to new contributors. Although AstNode* base classes needing to
be abstract is described in the internals manual, this might provide a
bit of extra safety.
Inlining used to set some VarRefs to point to new Var nodes, without
updating the dtype of the VarRef to the dtype of the new Var.
AstNode::sameTree does identity comparison on the dtype, so some trees
that were semantically the same did not compare as such with sameTree
because of the dtype. This in turn results in some missed opportunities
for combining equivalent SenTree sensitivities when the clock came from
outside.
The main goal of this patch is to enable splitting the full and
incremental tracing functions into multiple functions, which can then be
run in parallel at a later stage. It also simplifies further
experimentation as all of the interesting trace code construction now
happens in V3Trace. No functional change is intended by this patch, but
there are some implementation changes in the generated code.
Highlights:
- Pass symbol table directly to trace callbacks for simplicity.
- A new traceRegister function is generated which adds each trace
function as an individual callback, which means we can have multiple
callbacks for each trace function type.
- A new traceCleanup function is generated which clears the activity
flags, as the trace callbacks might be implemented as multiple functions.
- Re-worked sub-function handling so there is no separate sub-function
for each trace activity class. Sub-functions are generate when required
by splitting.
- traceFull/traceChg are now created in V3Trace rather than V3TraceDecl,
this requires carrying the trace value tree in TraceDecl until it
reaches V3Trace where the TraceInc nodes are created (previously a
TraceInc was also created in V3TraceDecl which carries the value).
Includes `timescale, $printtimescale, $timeformat.
VL_TIME_MULTIPLIER, VL_TIME_PRECISION, VL_TIME_UNIT have been removed
and the time precision must now match the SystemC time precision.
To get closer behavior to older versions, use e.g. --timescale-override
"1ps/1ps".
Replace the virtual type() method on AstNode with a non-virtual, inlined
accessor to a const member variable m_type. This means that in order to be
able to use this for type testing, it needs to be initialized based on the
final type of the node. This is achieved by passing the relevant AstType
value back through the constructor call chain. Most of the boilerplate
involved is auto generated by first feeding V3AstNodes.h through astgen to
get V3AstNodes__gen.h, which is then included in V3Ast.h. No client code
needs to be aware and there is no functional change intended.
Eliminating the virtual function call to fetch the node type identifier
results in measured compilation speed improvement of 5-10% as it
eliminates up to 20% of all mispredicted branches from the execution.
dynamic_cast can have large run-time cost, so here we implement type
tests for AstNode instances by checking the unique type() property, which
in turn is a constant generated by astgen. For leaf types in the AstNode
type hierarchy, this is a simple equality check. To handle intermediate
types, we generate the type ids of leaf types in a pre-order traversal of
the type hierarchy. This yields contiguous ranges of ids for sub-type
trees, which means we can check membership of a non-leaf type via 2
comparisons against a low and high id. This single patch makes Verilator
itself 6-13% faster (depending on which optimizations are enabled) on a
large design of over 250k lines of Verilog.
* Add more directives to configuration files
Allow to set the same directives in configuration files that can also
be set by comment attributes (such as /* verilator public */ etc).
* Add support for lint messsage waivers
Add configuration file switch '-match' for lint_off. It takes a string
with wildcards allowed and warnings will be matched against it (if
rule and file also match). If it matches, the warning is waived.
Fixes#1649 and #1514Closes#2072
Geza Lore
Wilson Snyder
Julien Margetts
Piotr Binkowski
Yutetsu TAKATSUKASA
Yossi Nivin
Stefan Wallentowitz