pyosys: tox for non-wheel builds, update instructions

- add `tox` to list of dependencies: saves builder(s) from manually having to manage a venv for python build dependencies
  - when building wheels, pip automatically creates the environment with those dependencies, so no need for tox
  - when running simply `make ENABLE_PYOSYS=1`, this is not the case. people attempting to `pip3 install --upgrade pybind11 cxxheaderparser` to add it to their system packages will be met with a scare message about "breaking system packages"
  - tox is available from all major package managers all the way back to ubuntu 20.04 and resolves this issue
- update installation instructions to drop boost and add tox instead
- update ci scripts to use `macos-15[-intel]` (`macos-13` sunset in early december)

.github/actions/setup-build-env/action.yml

@@ -8,7 +8,7 @@ runs:
       shell: bash
       run: |
         sudo apt-get update
-        sudo apt-get install gperf build-essential bison flex libfl-dev libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev libbz2-dev libgtest-dev
+        sudo apt-get install gperf build-essential bison flex libfl-dev libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3-dev tox zlib1g-dev libbz2-dev libgtest-dev
 
     - name: Install macOS Dependencies
       if: runner.os == 'macOS'

.github/workflows/test-compile.yml

@@ -45,7 +45,7 @@ jobs:
           - 'gcc-14'
         include:
           # macOS x86
-          - os: macos-13
+          - os: macos-15-intel
             compiler: 'clang-19'
           # macOS arm
           - os: macos-latest

.github/workflows/wheels.yml

@@ -27,13 +27,13 @@ jobs:
             {
               name: "macOS 13",
               family: "macos",
-              runner: "macos-13",
+              runner: "macos-15-intel",
               archs: "x86_64",
             },
             {
               name: "macOS 14",
               family: "macos",
-              runner: "macos-14",
+              runner: "macos-15",
               archs: "arm64",
             },
             ## Windows is disabled because of an issue with compiling FFI as

.gitignore

@@ -61,6 +61,7 @@
 /venv
 /*.whl
 /*.egg-info
+/.tox
 
 # yosysjs dependency
 /viz.js

Brewfile

@@ -6,9 +6,9 @@ brew "git"
 brew "graphviz"
 brew "pkg-config"
 brew "python3"
+brew "tox"
 brew "xdot"
 brew "bash"
-brew "boost-python3"
 brew "llvm@20"
 brew "lld"
 brew "googletest"

Makefile

@@ -28,6 +28,7 @@ ENABLE_HELP_SOURCE := 0
 
 # python wrappers
 ENABLE_PYOSYS := 0
+PYOSYS_USE_TOX := 1
 
 # other configuration flags
 ENABLE_GCOV := 0
@@ -352,16 +353,22 @@ PYTHON_OBJECTS = pyosys/wrappers.o kernel/drivers.o kernel/yosys.o passes/cmds/p
 
 ifeq ($(ENABLE_PYOSYS),1)
 # python-config --ldflags includes -l and -L, but LINKFLAGS is only -L
+
+TOX_ENV :=
+ifeq ($(PYOSYS_USE_TOX),1)
+TOX_ENV := tox -qq -e build --
+endif
+
 LINKFLAGS += $(filter-out -l%,$(shell $(PYTHON_CONFIG) --ldflags))
 LIBS += $(shell $(PYTHON_CONFIG) --libs)
 EXE_LIBS += $(filter-out $(LIBS),$(shell $(PYTHON_CONFIG_FOR_EXE) --libs))
-PYBIND11_INCLUDE ?= $(shell $(PYTHON_EXECUTABLE) -m pybind11 --includes)
+PYBIND11_INCLUDE ?= $(shell $(TOX_ENV) $(PYTHON_EXECUTABLE) -m pybind11 --includes)
 CXXFLAGS += -I$(PYBIND11_INCLUDE) -DYOSYS_ENABLE_PYTHON
 CXXFLAGS += $(shell $(PYTHON_CONFIG) --includes) -DYOSYS_ENABLE_PYTHON
 
 OBJS += $(PY_WRAPPER_FILE).o
 PY_GEN_SCRIPT = pyosys/generator.py
-PY_WRAP_INCLUDES := $(shell $(PYTHON_EXECUTABLE) $(PY_GEN_SCRIPT) --print-includes)
+PY_WRAP_INCLUDES := $(shell $(TOX_ENV) $(PYTHON_EXECUTABLE) $(PY_GEN_SCRIPT) --print-includes)
 endif # ENABLE_PYOSYS
 
 ifeq ($(ENABLE_READLINE),1)
@@ -777,7 +784,7 @@ endif
 ifeq ($(ENABLE_PYOSYS),1)
 $(PY_WRAPPER_FILE).cc: $(PY_GEN_SCRIPT) pyosys/wrappers_tpl.cc $(PY_WRAP_INCLUDES) pyosys/hashlib.h
 	$(Q) mkdir -p $(dir $@)
-	$(P) $(PYTHON_EXECUTABLE) $(PY_GEN_SCRIPT) $(PY_WRAPPER_FILE).cc
+	$(P) $(TOX_ENV) $(PYTHON_EXECUTABLE) $(PY_GEN_SCRIPT) $(PY_WRAPPER_FILE).cc
 endif
 
 %.o: %.cpp

README.md

@@ -85,8 +85,7 @@ prerequisites for building yosys:
 
 	$ sudo apt-get install build-essential clang lld bison flex libfl-dev \
 		libreadline-dev gawk tcl-dev libffi-dev git \
-		graphviz xdot pkg-config python3 libboost-system-dev \
+		graphviz xdot pkg-config python3-dev tox zlib1g-dev
-		libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
 The environment variable `CXX` can be used to control the C++ compiler used, or
 run one of the following to override it:

docs/source/getting_started/installation.rst

@@ -99,8 +99,7 @@ Installing all prerequisites for Ubuntu 22.04:
 
    sudo apt-get install gperf build-essential clang lld bison flex libfl-dev \
       libreadline-dev gawk tcl-dev libffi-dev git \
-      graphviz xdot pkg-config python3 libboost-system-dev \
+      graphviz xdot pkg-config python3-dev tox zlib1g-dev
-      libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
 Installing all prerequisites for macOS 13 (with Homebrew):
 
@@ -141,7 +140,7 @@ For Cygwin use the following command to install all prerequisites, or select the
    missing `strdup` function when using gcc.  It is instead recommended to use
    Windows Subsystem for Linux (WSL) and follow the instructions for Ubuntu.
 
-.. 
+..
    For MSYS2 (MINGW64):
 
    .. code:: console
@@ -215,7 +214,7 @@ Running the build system
 From the root ``yosys`` directory, call the following commands:
 
 .. code:: console
-   
+
    make
    sudo make install
 
@@ -228,7 +227,7 @@ To use a separate (out-of-tree) build directory, provide a path to the Makefile.
 
 Out-of-tree builds require a clean source tree.
 
-.. seealso:: 
+.. seealso::
 
    Refer to :doc:`/yosys_internals/extending_yosys/test_suites` for details on
    testing Yosys once compiled.

docs/source/using_yosys/pyosys.rst

@@ -28,6 +28,14 @@ methods:
 
    ``yosys -y ./my_pyosys_script.py``
 
+   Do note this requires some build-time dependencies to be available to Python,
+   namely, ``pybind11`` and ``cxxheaderparser``. By default, the required
+   ``tox`` package will be used to create an ephemeral environment with the
+   correct versions of the tools installed.
+
+   You can force use of your current Python environment by passing the Makefile
+   flag ``PYOSYS_USE_TOX=0``.
+
 2. Installing the Pyosys wheels
 
    On macOS and GNU/Linux you can install pre-built wheels of Yosys using

tox.ini

@@ -0,0 +1,9 @@
+[tox]
+envlist = build
+
+[testenv:build]
+skip_install = true
+deps =
+    pybind11>=3,<4
+    cxxheaderparser
+commands = {posargs}