Commit Graph

128 Commits

Author SHA1 Message Date
Robin Ole Heinemann 8bc4bd8a20 cxxrtl, fmt: escape double quotes in c strings 2024-11-11 18:49:05 +00:00
Emil J. Tywoniak 785bd44da7 rtlil: represent Const strings as std::string 2024-10-14 06:28:12 +02:00
Asherah Connor e97c36d4c4 cxxrtl: don't emit syncs for empty lhs. 2024-06-07 14:24:27 +03:00
Amiot Noe c7580eb18e cxxrtl: Prevent wires with input or output ports from being aliased 2024-05-24 23:26:16 +01:00
Catherine 6e003e1af6 cxxrtl: minimize stack space consumed by `debug_info()`.
This commit uses parameter packs to sink `debug_item()` construction
into the `debug_info()`-specific `add()` overload. This makes the stack
space use sub-linear in typical case rather than linear (which is still
the worst case). Oddly, the stack slots that get allocated now are all
for the `0` literal for `lsb_offset`. This could be fixed by allocating
numbers statically but the existing reduction in stack use of ~98% for
a representative example (Minerva SoC) should be enough.
2024-05-08 03:37:14 +00:00
Catherine 80798daf53 cxxrtl: reduce stack space consumed by `debug_info()` further.
Before this commit, this function would create a temporary `std::string`
per debug item (and scope). After this commit, an additional overload is
used to push that down the call stack. This reduces stack usage by
about 50% more on top of the previous commit.
2024-05-08 02:55:17 +00:00
Catherine 9134cd1928 cxxrtl: reduce stack space consumed by `debug_info()`.
Before this commit, the creation of (constant) attribute maps caused
`debug_info()` (which is built with `__attribute__((optnone))`) to
consume large amounts of stack space; up to tens of megabytes. This
caused problems particularly on macOS, where the default stack size
is 512 KiB.

After this commit, `std::map` objects are no longer created inline in
the `debug_info()` function, but are compiled to and then expanded from
a string literal in a subroutine call. This reduces stack space usage
by about 50%.
2024-05-08 02:55:17 +00:00
Catherine 43ddd89ba5 cxxrtl: fix `escape_c_string` hex literal fiasco.
In C and C++, a `\x` escape sequence consumes as many hexadecimal digits
as there are available, so it is not composable with arbitrary alnum
characters afterwards. An octal escape sequence like `\000` always has
fixed width, avoiding an issue where `\x01c` and `\x1c` produce the same
string.
2024-05-08 02:55:17 +00:00
Catherine 1a44645aef cxxrtl: expose scope information in the C++ API.
This commit adds a `debug_scopes` container, which can collect metadata
about scopes in a design. Currently the only scope is that of a module.
A module scope can be represented either by a module and cell pair, or
a `$scopeinfo` cell in a flattened netlist. The metadata produced by
the C++ API is identical between these two cases, so flattening remains
transparent to a netlist with CXXRTL.

The existing `debug_items` method is deprecated. This isn't strictly
necessary, but the user experience is better if the path is provided
as e.g. `"top "` (as some VCD viewers make it awkward to select topmost
anonymous scope), and the upgrade flow encourages that, which should
reduce frustration later.

While the new `debug_items` method could still be broken in the future
as the C++ API permits, this seems unlikely since the debug information
can now capture all common netlist aspects and includes several
extension points (via `debug_item`, `debug_scope` types).

Also, naming of scope paths was normalized to `path` or `top_path`,
as applicable.
2024-02-26 12:42:48 +00:00
Catherine d903f47d41 write_cxxrtl: don't assert on `-noflatten` with `-g4`. 2024-02-26 12:42:48 +00:00
Catherine 569a6d7fea cxxrtl: make blackbox `commit()` possible to override.
This fixes a regression introduced when commit observers were added.
2024-02-26 10:29:19 +00:00
Catherine c7bf0e3b8f Add new `$check` cell to represent assertions with a message. 2024-02-01 20:10:39 +01:00
Catherine b841d1bcbe cxxrtl: fix typo in codegen for async set/clear. 2024-01-24 16:30:01 +00:00
Catherine fc5ff7a265 cxxrtl: always lazily format print messages.
This is mostly useful for collecting coverage for the future `$check`
cell, where, depending on the flavor, formatting a message may not be
wanted even for a failed assertion.
2024-01-19 18:55:23 +00:00
Catherine b74d33d1b8 fmt: rename TIME to VLOG_TIME.
The behavior of these format specifiers is highly specific to Verilog
(`$time` and `$realtime` are only defined relative to `$timescale`)
and may not fit other languages well, if at all. If they choose to use
it, it is now clear what they are opting into.

This commit also simplifies the CXXRTL code generation for these format
specifiers.
2024-01-19 15:12:05 +00:00
Catherine 5a1fcdea13 cxxrtl: include attributes in `performer::on_print` callback.
This is useful primarily to determine the source location, but can also
be used for any other purpose.
2024-01-16 16:39:11 +00:00
Catherine 905f07c03f cxxrtl: introduce `performer`, a context object for `eval()`. (breaking change)
At the moment the only thing it allows is redirecting `$print` cell
output in a context-dependent manner. In the future, it will allow
customizing handling of `$check` cells (where the default is to abort),
of out-of-range memory accesses, and other runtime conditions with
effects.

This context object also allows a suitably written testbench to add
Verilog-compliant `$time`/`$realtime` handling, albeit it involves
the ceremony of defining a `performer` subclass. Most people will
want something like this to customize `$time`:

    int64_t time = 0;
    struct : public performer {
      int64_t *time_ptr;
      int64_t time() const override { return *time_ptr; }
    } performer = { &time };

    p_top.step(&performer);
2024-01-16 16:37:07 +00:00
Catherine 02e3d508fa cxxrtl: remove `module::steps`. (breaking change)
This approach to tracking simulation time was a mistake that I did not
catch in review. It has several issues:
1. There is absolutely no requirement to call `step()`, as it is
   a convenience function. In particular, `steps` will not be
   incremented in submodules if `-noflatten` is used.
2. The semantics of `steps` does not match that of the Verilog `$time`
   construct.
3. There is no way to make the semantics of `%t` match that of Verilog.
4. The `module` interface is intentionally very barebones. It is little
   more than a container for three method pointers, `reset`, `eval`,
   and `commit`. Adding ancillary data to it goes against this.

If similar functionality is introduced again it should probably be
a variable that is global per toplevel design using some object that is
unique for an entire hierarchy of modules, and ideally exposed via
the C API. For now, it is being removed (in this commit) and (in next
commit) the capability is being reintroduced through a context object
that can be specified for `eval()`.
2024-01-16 16:35:51 +00:00
Catherine a33acb7cd9 cxxrtl: refactor the formatter and use a closure.
This commit achieves three roughly equally important goals:
1. To bring the rendering code in kernel/fmt.cc and in cxxrtl.h as close
   together as possible, with an ideal of only having the bigint library
   as the difference between the render functions.
2. To make the treatment of `$time` and `$realtime` in CXXRTL closer to
   the Verilog semantics, at least in the formatting code.
3. To change the code generator so that all of the `$print`-to-`string`
   conversion code is contained inside of a closure.

There are two reasons to aim for goal (3):
a. Because output redirection through definition of a global ostream
   object is neither convenient nor useful for environments where
   the output is consumed by other code rather than being printed on
   a terminal.
b. Because it may be desirable to, in some cases, ignore the `$print`
   cells that are present in the netlist based on a runtime decision.
   This is doubly true for an upcoming `$check` cell implementing
   assertions, since failing a `$check` would by default cause a crash.
2024-01-16 16:35:51 +00:00
Catherine bf1a99da09 cxxrtl: make observer methods non-virtual. (breaking change)
This avoids having to devirtualize them later to get performance back,
and simplifies the code a bit.

The change is prompted by the desire to add a similar observer object
to `eval()`, and a repeated consideration of whether the dispatch on
these should be virtual in first place.
2024-01-16 09:58:21 +00:00
Catherine 7142e20dab write_cxxrtl: support initial `$print` cells. 2024-01-11 15:27:21 +01:00
Catherine d493225313 write_cxxrtl: reset state value of comb `$print` cells. 2024-01-11 15:17:06 +01:00
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