Migrate build system to CMake

See #5895 for details.

This commit does not include CI or documentation changes.

cmake/PmgenCommand.cmake

@@ -0,0 +1,60 @@
+# Syntax:
+#
+# 	pmgen_command(<output>
+# 		[<input>...]
+# 		[PREFIX <prefix>]
+# 		[DEBUG]
+# 	)
+#
+# Builds `<output>_pm.h` in the current binary directory from pmgen source files `<input>`, which must have
+# the `*.pmg` extension.  If `<input>...` contains more than one file, `<prefix>` must be provided.
+#
+# Defines the following variables:
+#   - `PMGEN_<output>_DEFINED`: Boolean indicating whether this command was successfully invoked.
+#   - `PMGEN_<output>_OUTPUT`: The header file generated by `pmgen`.
+#
+# Usage example:
+#
+# 	pmgen_command(my_dsp
+# 		my_dsp.pmg
+# 	)
+# 	yosys_pass(my_dsp
+# 		my_dsp.cc
+# 		${PMGEN_my_dsp_OUTPUT}
+# 	)
+#
+# Usage example with multiple files:
+#
+# 	pmgen_command(my_dsp
+# 		my_dsp_macc.pmg
+# 		my_dsp_carry.pmg
+# 		PREFIX
+# 			my_dsp
+# 	)
+#
+function(pmgen_command arg_NAME)
+	cmake_parse_arguments(PARSE_ARGV 1 arg "DEBUG" "PREFIX" "")
+	set(arg_INPUTS ${arg_UNPARSED_ARGUMENTS})
+
+	set(pmgen_script ${CMAKE_SOURCE_DIR}/passes/pmgen/pmgen.py)
+	set(pmgen_output ${CMAKE_CURRENT_BINARY_DIR}/${arg_NAME}_pm.h)
+	cmake_path(RELATIVE_PATH pmgen_output BASE_DIRECTORY ${CMAKE_BINARY_DIR} OUTPUT_VARIABLE pmgen_output_rel)
+	add_custom_command(
+		DEPENDS ${pmgen_script} ${arg_INPUTS}
+		OUTPUT ${pmgen_output}
+		COMMAND ${Python3_EXECUTABLE}
+			${pmgen_script}
+			"$<$<BOOL:${arg_DEBUG}>:-g>"
+			"$<$<BOOL:${arg_PREFIX}>:-p;${arg_PREFIX}>"
+			-o ${pmgen_output}
+			${arg_INPUTS}
+		COMMAND_EXPAND_LISTS
+		WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+		VERBATIM
+		COMMENT "Compiling pattern matcher ${pmgen_output_rel}"
+	)
+
+	# The usage of this command is somewhat inspired by `flex_target()` and `bison_target()`.
+	set(PMGEN_${arg_NAME}_DEFINED TRUE)
+	set(PMGEN_${arg_NAME}_OUTPUT ${pmgen_output} PARENT_SCOPE)
+endfunction()