This patch partitions AstCFuncs under an AstNodeModule based on which
header files they require for their implementation, and emits them
into separate files based on the distinct dependency sets. This helps
with incremental recompilation of the output C++.
Apart from adding required AstCUse, V3CUse also used to create some
standard methods for classes. This is now done in a separate pass
V3Common. Note that this is not a performance issue, as V3Common just
iterates through each module, which are stored in a simple linked list
under the netlist, and does not need to traverse the whole netlist.
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.
Internal AstNodeModule headers (.h) and implementation (.cpp) files are
now emitted separately in V3EmitC::emitcHeaders() and
V3EmitC::emitcImp() respectively. No functional change intended
A separate V3VariableOrder pass is now used to order module variables
before Emit. All variables are now ordered together, without
consideration for whether they are ports, signals form the design, or
additional internal variables added by Verilator (which used to be
ordered and emitted as separate groups in Emit). For single threaded
models, this is performance neutral. For multi-threaded models, the
MTask affinity based sorting was slightly modified, so variables with no
MTask affinity are emitted last, otherwise the MTask affinity sets are
sorted using the TSP sorter as before, but again, ports, signals, and
internal variables are not differentiated. This yields a 2%+ speedup for
the multithreaded model on OpenTitan.
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.
Do not sort and hoist function local variables to the top of the
function definition. The stack layout of automatic variables is not
defined by C so the compilers can lay these out optimally. Simplifies
internals for follow on work. Effect on model performance is neutral to
very slight improvement, so we do not seem to be loosing anything.
V3Broken now checks that AstVar nodes referenced in an AstCFunc are
either external, or appear in the tree before the reference, and are in
scope.
Fix V3Begin to move lifted AstVars to beginning of FTask, rather than
end, which trips the above check.
debug() declared by VL_DEGUB_FUNC used to cache the result of the debug
level lookup (which depends on options) in a static. This meant that if
the debug() function was called before option parsing, the default debug
level of 0 would be used for the rest of the program, even if a --debug
option was given. Fixed by not caching the debug level until after
option parsing is complete.
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.
The -G option now correctly parses simple integer literals as signed
numbers, which is in line with the standard and is significant when
overriding parameters without a type specifier.
Fixes#3060
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.
For consistency with the rest of the generated code, generated methods
related to tracing now use snake_case instead of camelCase. No
functional change intended.
* Move MTaskState to ThreadSchedule
MTaskState does not concern itself with sandbagging, and thus solely contains information related to the finalized schedule, i.e., completion time, thread ID and next MTask on thread.
* Add .dot graph visualization of ThreadSchedule
Follow-up to #2779.
This commit adds the creation of .dot files - used by GraphViz - to visualize how mtasks are statically scheduled across the set of specified threads.
We visualize each thread as a row, with nodes of a row being the mtasks scheduled for the given thread. The width of the mtask nodes are proportional to their cost. MTask dependencies are shown using an edge between the source and sink mtasks.
V3Simulate reuses allocated AstConst nodes for efficiency, however this
used to be implemented in a way that required a deep copy of a
std::unorderd_map<_, std::deque<_>>, which was quite inefficient when it
grew large. The free list is now managed without any copying. This takes
the V3Table pass from taking 12s to 0.2s on SweRV EH1.
Tests used to silently pass when vcddiff aborted. Now fixed. Updated
large array trace reference files for FST, added same reference files
for VCD.
Developers need to update their local vcddiff.
