Commit Graph

106 Commits

Author SHA1 Message Date
Catherine 3e358d9bfa cxxrtl: add a way to observe state changes during the commit step.
The commit observer is a structure containing a callback that is invoked
whenever the `commit()` method changes a wire or a memory. This allows
code external to the compiled netlist to react to changes in the design
state in a very efficient way. One example of how this feature can be
used is an efficient implementation of record/replay.

Note that the VCD writer does not benefit from this feature because it
must be able to react to changes in any debug items and not just those
that contain design state.
2024-01-05 19:02:00 +00:00
Henri Nurmi 1c8e58a736 cxxrtl: Fix formating 2023-12-13 06:08:01 +00:00
Henri Nurmi 79c0bfcb22 cxxrtl: Remove unnecessary length check 2023-12-13 06:08:01 +00:00
Henri Nurmi dbff694e3d cxxrtl: Use the base name of the interface file for the include directive
Prior to this fix, the `CxxrtlBackend` used the entire path for the include
directive when a separated interface file is generated (via the `-header`
option). This commit updates the code to use the base name of the interface
file.

Since the C++11 standard is used by default, we cannot take advantage of
the `std::filesystem` to get the basename.
2023-12-13 06:08:01 +00:00
Catherine 62bbd086b1 cxxrtl: reorganize runtime component files.
In preparation for substantial expansion of CXXRTL's runtime, this commit
reorganizes the files used by the implementation. Only minimal changes are
required in a consumer.

First, change:
  -I$(yosys-config --datdir)/include
to:
  -I$(yosys-config --datdir)/include/backends/cxxrtl/runtime

Second, change:
  #include <backends/cxxrtl/cxxrtl.h>
to:
  #include <cxxrtl/cxxrtl.h>
(and do the same for cxxrtl_vcd.h, etc.)
2023-11-28 15:32:36 +00:00
Catherine 6ffc315936 cxxrtl: export wire attributes through the C API.
Co-authored-by: Charlotte <charlotte@lottia.net>
2023-10-25 16:01:48 +00:00
Asherah Connor 4a475fa7a2 cxxrtl: include iostream when prints are used 2023-08-17 07:08:22 +02:00
Charlotte 2829cd9caa cxxrtl_backend: move sync $print grouping out of dump into analyze 2023-08-11 04:46:52 +02:00
Charlotte ce245b5105 cxxrtl_backend: respect sync `$print` priority
We add a new flow graph node type, PRINT_SYNC, as they don't get handled
with regular CELL_EVALs.  We could probably move this grouping out of
the dump method.
2023-08-11 04:46:52 +02:00
Charlotte 4ffdee65e0 cxxrtl: store comb $print cell last EN/ARGS in module
statics were obviously wrong -- may be multiple instantiations of any
given module.  Extend test to cover this.
2023-08-11 04:46:52 +02:00
Charlotte 843ad9331b cxxrtl: WIP: adjust comb display cells to only fire on change
Naming and use of statics to be possibly revised.
2023-08-11 04:46:52 +02:00
Charlotte fc0acd0ad1 cxxrtl: restrict -print-output to cout, cerr 2023-08-11 04:46:52 +02:00
Charlotte f9b149fa7b cxxrtl: add "-print-output" option, test in fmt 2023-08-11 04:46:52 +02:00
Charlotte 095b093f4a cxxrtl: first pass of $print impl 2023-08-11 04:46:52 +02:00
Charlotte eb397592f0 cxxrtl: add `$divfloor`. 2023-06-28 15:27:06 +01:00
Michael Nolan 24b895778a Add support for GHDL modfloor operator 2022-07-05 15:15:54 -04:00
Marcelina Kościelnicka 93508d58da Add $bmux and $demux cells. 2022-01-28 23:34:41 +01:00
Catherine fc049e84a9 cxxrtl: don't reset elided wires with \init attribute. 2021-12-25 01:06:10 +00:00
Catherine 7f2ea7d222 cxxrtl: demote wires not inlinable only in debug_eval to locals.
Fixes #3112.

Co-authored-by: Irides <irides@irides.network>
2021-12-15 09:14:33 +00:00
Catherine 55c9fb3b18 cxxrtl: preserve interior memory pointers across reset.
Before this commit, values, wires, and memories with an initializer
were value-initialized in emitted C++ code. After this commit, all
values, wires, and memories are default-initialized, and the default
constructor of generated modules calls the reset() method, which
assigns the members that have an initializer.
2021-12-11 16:40:06 +00:00
Marcelina Kościelnicka e7d89e653c Hook up $aldff support in various passes. 2021-10-02 21:01:21 +02:00
Marcelina Kościelnicka e6f3d1c225 kernel/mem: Introduce transparency masks. 2021-08-11 00:04:16 +02:00
whitequark a04844bdf8
Merge pull request #2885 from whitequark/cxxrtl-fix-2883
cxxrtl: treat wires with multiple defs as not inlinable
2021-07-20 13:12:11 +00:00
whitequark 1a6ddf7892 cxxrtl: treat wires with multiple defs as not inlinable.
Fixes #2883.
2021-07-20 10:30:39 +00:00
whitequark 225af830c1 cxxrtl: treat assignable internal wires used only for debug as locals.
This issue was introduced in commit 4aa65f40 while fixing #2739.

Fixes #2882.
2021-07-20 10:10:42 +00:00
whitequark 4aa65f406f cxxrtl: treat internal wires used only for debug as constants.
Fixes #2739 (again).
2021-07-17 14:23:57 +00:00
whitequark 2db4137514
Merge pull request #2874 from whitequark/cxxrtl-fix-2589
cxxrtl: run hierarchy pass regardless of (*top*) attribute presence
2021-07-16 11:12:19 +00:00
whitequark efc43270fa
Merge pull request #2873 from whitequark/cxxrtl-fix-2500
cxxrtl: emit debug items for unused public wires
2021-07-16 11:01:10 +00:00
whitequark 5b003d6e5c cxxrtl: run hierarchy pass regardless of (*top*) attribute presence.
The hierarchy pass does a lot more than just finding the top module,
mainly resolving implicit (positional, wildcard) module connections.

Fixes #2589.
2021-07-16 10:27:47 +00:00
whitequark 09218896d6 cxxrtl: emit debug items for unused public wires.
This greatly improves debug information coverage.

Fixes #2500.
2021-07-16 10:14:40 +00:00
whitequark b28ca7f5ac cxxrtl: don't expect user cell inputs to be wires.
Ports can be connected to constants, too. (Usually resets.)

Fixes #2521.
2021-07-16 09:51:52 +00:00
whitequark 44a3d924ce cxxrtl: don't mark buffered internal wires as UNUSED for debug.
Public wires may alias buffered internal wires, so keep BUFFERED
wires in debug information even if they are private. Debug items are
only created for public wires, so this does not otherwise affect how
debug information is emitted.

Fixes #2540.
Fixes #2841.
2021-07-16 07:54:49 +00:00
whitequark 54b6cb645f cxxrtl: mark dead local wires as unused even with inlining disabled.
Fixes #2739.
2021-07-15 22:27:27 +00:00
Marcelina Kościelnicka 8bf9cb407d kernel/mem: Add a coalesce_inits helper.
While this helper is already useful to squash sequential initializations
into one in cxxrtl, its main purpose is to squash overlapping masked memory
initializations (when they land) and avoid having to deal with them in
cxxrtl runtime.
2021-07-13 15:59:11 +02:00
Marcelina Kościelnicka 37506d737c cxxrtl: Support memory writes in processes. 2021-07-12 18:27:48 +02:00
Marcelina Kościelnicka af7fa62251 cxxrtl: Add support for memory read port reset. 2021-07-12 18:27:48 +02:00
Marcelina Kościelnicka be5cf29699 cxxrtl: Add support for mem read port initial data. 2021-07-12 18:27:48 +02:00
Marcelina Kościelnicka d5c9595668 cxxrtl: Convert to Mem helpers.
This *only* does conversion, but doesn't add any new functionality —
support for memory read port init/reset is still upcoming.
2021-07-12 18:27:48 +02:00
whitequark ab76d9cec5 cxxrtl: don't assert on edge sync rules tied to a constant.
These are commonly the result of tying an async reset to an inactive
level.
2021-03-07 14:29:30 +00:00
whitequark d1de08e38a cxxrtl: allow `always` sync rules in debug_eval.
These can be produced from `always @*` processes, if `-noproc`
is used.
2021-03-07 14:28:45 +00:00
whitequark 9dd813374e
Merge pull request #2635 from whitequark/cxxrtl-memrd-async-addr
cxxrtl: follow aliases to outlines when emitting $memrd.ADDR
2021-03-05 05:30:19 -08:00
whitequark 06da2e0f18
Merge pull request #2634 from whitequark/cxxrtl-debug-wire-types
cxxrtl: add pass debug flag to show assigned wire types
2021-03-05 04:57:22 -08:00
whitequark 14ce8bdaa6 cxxrtl: follow aliases to outlines when emitting $memrd.ADDR. 2021-03-05 12:09:02 +00:00
whitequark 8471808834 cxxrtl: add pass debug flag to show assigned wire types.
Refs #2543.
2021-03-05 11:58:59 +00:00
whitequark a9a873a1d2 cxxrtl: don't crash on empty designs. 2021-03-05 11:05:19 +00:00
Iris Johnson c8415884d1 Improves the previous commit with a more complete coverage of the cases 2021-01-15 13:59:20 -06:00
Iris Johnson 86607d0fdc Handle sliced bits as clock inputs (fixes #2542) 2021-01-14 16:36:21 -06:00
whitequark f14074d2c2 cxxrtl: don't crash generating debug information for unused wires. 2020-12-22 06:51:38 +00:00
whitequark 7378194169 cxxrtl: split processes into sync and case nodes.
Similar to the treatment of black boxes, splitting processes into two
scheduling nodes adds sufficient freedom so that netlists with
well-behaved processes (e.g. those emitted by nMigen) can immediately
converge.

Because processes are not emitted into edge-triggered regions, this
approach has comparable performance to -O5 (without -noproc), which
is substantially slower than -O6.
2020-12-22 03:48:09 +00:00
whitequark b2221c1077 cxxrtl: completely rewrite netlist layout code.
The exact shape of C++ code emitted by CXXRTL has a critical effect
on performance, both compile-time and runtime. CXXRTL's performance
greatly improved when it started localizing and inlining wires, not
only because this assists the optimizer and register allocator, but
also because inlining code into edge-triggered regions cuts the time
spent in eval() by at least a factor of two.

However, the logic of netlist layout has always been ad-hoc, fragile,
and very hard to understand and modify. After commit ece25a45, which
introduced outlining, the same logic started being applied to two
distinct netlists at once instead of one, which barely worked.

This commit does four major changes:
  * There is now a single unambiguous source of truth (per subgraph)
    for the layout of any emitted wire.
  * Netlist layout is now done entirely during analysis using well
    known graph algorithms; no graph operations happen when emitting.
  * Netlist layout now happens completely separately for eval() and
    debug_eval() subgraphs.
  * Unreachable (within subgraph scope) netlist nodes are now neither
    emitted nor considered for wire inlining decisions.
The netlist layout code should also now closely match the described
semantics.

As a part of this large cleanup, it includes many miscellaneous
improvements:
  * The "bare minimum" debug level introduced in commit dd6a761d was
    split into two levels; -g1 now emits debug information *only* for
    inputs and state wires, and -g2 now emits debug information for
    all public members. The old behavior matches -g2. This is done
    to avoid bloat on low optimization levels.
  * Debug aliases and inlined connections are now handled separately,
    and complex RHS never interferes with inlined connections.
  * Aliases to outlined wires now carry a pointer to the outline.
  * Cell sync outputs can now be emitted in debug_eval().
  * Black box debug information now includes comb/sync driver flags.
  * The comment emitted for inlined cells is now accurate.
  * Debug information statistics now has less noise.
  * Netlist layout code is now much better documented.

Due to more precise inlining decisions, unmodified (i.e. with no
Yosys script being used) netlists now have much more logic inlined
into edge-triggered regions. On Minerva SoC SRAM, this improves
runtime by 20-25% across compilers and optimization levels.

Due to more precise reachability analysis, much less C++ code is now
emitted, especially at the maximum debug level. On Minerva SoC SRAM,
this improves clang compile time by 30-50% depending on options.
gcc is not affected.
2020-12-22 03:48:09 +00:00