cxxsim: basic support.

Author: kivikakk

rainhdx/rainhdx/__init__.py

@@ -1,13 +1,12 @@
 import json
-import logging
 import sys
 from argparse import ArgumentParser
 from functools import partialmethod
 from pathlib import Path
 
 from amaranth import Elaboratable
 
-from . import build, formal, logger, test
+from . import build, cxxsim, formal, test
 from .platform import Platform
 
 __all__ = ["Project", "Platform", "FormalHelper", "cli"]
@@ -63,6 +62,12 @@ class Project:
             required=True,
             issubclass=Elaboratable,
         ),
+        Prop(
+            "cxxsim_top",
+            description="a reference to the top-level C++ simulator test elaboratable",
+            required=False,
+            issubclass=Elaboratable,
+        ),
         Prop(
             "formal_top",
             description="a reference to the top-level formal elaboratable",
@@ -102,7 +107,10 @@ def cli(rp):
     subparsers = parser.add_subparsers(required=True)
 
     test.add_arguments(rp, subparsers.add_parser("test", help="run the unit tests"))
-    # cxxsim
+    if hasattr(rp, "cxxsim_top"):
+        cxxsim.add_arguments(
+            rp, subparsers.add_parser("cxxsim", help="run the C++ simulator tests")
+        )
     if hasattr(rp, "formal_top"):
         formal.add_arguments(
             rp, subparsers.add_parser("formal", help="formally verify the design")

rainhdx/rainhdx/cxxsim.py

@@ -0,0 +1,123 @@
+import inspect
+import subprocess
+from enum import Enum
+from functools import partial
+from pathlib import Path
+
+from amaranth._toolchain.yosys import find_yosys
+from amaranth.back import rtlil
+
+from .platform import Platform
+
+__all__ = ["add_arguments"]
+
+
+class _Optimize(Enum):
+    none = "none"
+    rtl = "rtl"
+
+    def __str__(self):
+        return self.value
+
+    @property
+    def opt_rtl(self) -> bool:
+        return self in (self.rtl,)
+
+
+def add_arguments(rp, parser):
+    parser.set_defaults(func=partial(main, rp))
+    parser.add_argument(
+        "-c",
+        "--compile",
+        action="store_true",
+        help="compile only; don't run",
+    )
+    parser.add_argument(
+        "-O",
+        "--optimize",
+        type=_Optimize,
+        choices=_Optimize,
+        help="build with optimizations (default: rtl)",
+        default=_Optimize.rtl,
+    )
+    parser.add_argument(
+        "-v",
+        "--vcd",
+        action="store_true",
+        help="output a VCD file",
+    )
+
+
+def main(rp, args):
+    yosys = find_yosys(lambda ver: ver >= (0, 10))
+
+    platform = Platform["cxxsim"]
+    sig = inspect.signature(rp.cxxsim_top)
+    kwargs = {}
+    if "platform" in sig.parameters:
+        kwargs["platform"] = platform
+    design = rp.cxxsim_top(**kwargs)
+
+    cxxrtl_cc_path = rp.path.build(f"{rp.name}.cc")
+    _cxxrtl_convert_with_header(
+        yosys,
+        cxxrtl_cc_path,
+        design,
+        platform,
+        black_boxes={},
+        ports=design.ports(platform),
+    )
+
+    cc_o_paths = {
+        rp.path("cxxsim/main.cc"): rp.path.build("main.o"),
+    }
+
+    for cc_path, o_path in cc_o_paths.items():
+        subprocess.run(
+            [
+                "c++",
+                *(["-O3"] if args.optimize.opt_rtl else []),
+                "-I" + str(rp.path(".")),
+                "-I" + str(yosys.data_dir() / "include" / "backends" / "cxxrtl" / "runtime"),
+                "-c",
+                cc_path,
+                "-o",
+                o_path,
+            ],
+            check=True,
+        )
+
+    exe_o_path = rp.path.build("cxxsim")
+    subprocess.run(
+        [
+            "c++",
+            *(["-O3"] if args.optimize.opt_rtl else []),
+            *cc_o_paths.values(),
+            "-o",
+            exe_o_path,
+        ],
+        check=True,
+    )
+
+    if not args.compile:
+        cmd = [exe_o_path]
+        if args.vcd:
+            cmd += ["--vcd"]
+        subprocess.run(cmd, cwd=rp.path("cxxsim"), check=True)
+
+
+def _cxxrtl_convert_with_header(yosys, cc_out, design, platform, *, black_boxes, ports):
+    if cc_out.is_absolute():
+        try:
+            cc_out = cc_out.relative_to(Path.cwd())
+        except ValueError:
+            raise AssertionError(
+                "cc_out must be relative to cwd for builtin-yosys to write to it"
+            )
+    rtlil_text = rtlil.convert(design, platform=platform, ports=ports)
+    script = []
+    for box_source in black_boxes.values():
+        script.append(f"read_rtlil <<rtlil\n{box_source}\nrtlil")
+    script.append(f"read_rtlil <<rtlil\n{rtlil_text}\nrtlil")
+    script.append(f"write_cxxrtl -header {cc_out}")
+    yosys.run(["-q", "-"], "\n".join(script))