back.cxxrtl: allow injecting black boxes.

diff --git a/nmigen/back/cxxrtl.py b/nmigen/back/cxxrtl.py
index 8010539e03b98fea367e112b9ae8de0cd778a605..38cb41b15a2c6f4cacf35f4e18d7ebee974525c0 100644 (file)
--- a/nmigen/back/cxxrtl.py
+++ b/nmigen/back/cxxrtl.py
@@ -5,23 +5,38 @@ from . import rtlil
 __all__ = ["YosysError", "convert", "convert_fragment"]
 
 
-def _convert_rtlil_text(rtlil_text, *, src_loc_at=0):
+def _convert_rtlil_text(rtlil_text, black_boxes, *, src_loc_at=0):
+    if black_boxes is not None:
+        if not isinstance(black_boxes, dict):
+            raise TypeError("CXXRTL black boxes must be a dictionary, not {!r}"
+                            .format(black_boxes))
+        for box_name, box_source in black_boxes.items():
+            if not isinstance(box_name, str):
+                raise TypeError("CXXRTL black box name must be a string, not {!r}"
+                                .format(box_name))
+            if not isinstance(box_source, str):
+                raise TypeError("CXXRTL black box source code must be a string, not {!r}"
+                                .format(box_source))
+
      # FIXME: update this requirement once Yosys updates its node version
     yosys = find_yosys(lambda ver: ver >= (0, 9))
-    return yosys.run(["-q", "-"], """
-read_ilang <<rtlil
-{}
-rtlil
-delete w:$verilog_initial_trigger
-write_cxxrtl
-""".format(rtlil_text), src_loc_at=1 + src_loc_at)
+
+    script = []
+    if black_boxes is not None:
+        for box_name, box_source in black_boxes.items():
+            script.append("read_ilang <<rtlil\n{}\nrtlil".format(box_source))
+    script.append("read_ilang <<rtlil\n{}\nrtlil".format(rtlil_text))
+    script.append("delete w:$verilog_initial_trigger")
+    script.append("write_cxxrtl")
+
+    return yosys.run(["-q", "-"], "\n".join(script), src_loc_at=1 + src_loc_at)
 
 
-def convert_fragment(*args, **kwargs):
+def convert_fragment(*args, black_boxes=None, **kwargs):
     rtlil_text, name_map = rtlil.convert_fragment(*args, **kwargs)
-    return _convert_rtlil_text(rtlil_text, src_loc_at=1), name_map
+    return _convert_rtlil_text(rtlil_text, black_boxes, src_loc_at=1), name_map
 
 
-def convert(*args, **kwargs):
+def convert(*args, black_boxes=None, **kwargs):
     rtlil_text = rtlil.convert(*args, **kwargs)
-    return _convert_rtlil_text(rtlil_text, src_loc_at=1)
+    return _convert_rtlil_text(rtlil_text, black_boxes, src_loc_at=1)