Generate register bank descriptions.

Use the information in the ISA's registers.py files to generate a
RegInfo Rust data structure.

lib/cretonne/meta/gen_registers.py

@@ -0,0 +1,51 @@
+"""
+Generate register bank descriptions for each ISA.
+"""
+
+from __future__ import absolute_import
+import srcgen
+
+try:
+    from typing import Sequence  # noqa
+    from cdsl.isa import TargetISA  # noqa
+    from cdsl.registers import RegBank  # noqa
+except ImportError:
+    pass
+
+
+def gen_regbank(regbank, fmt):
+    # type: (RegBank, srcgen.Formatter) -> None
+    """
+    Emit a static data definition for regbank.
+    """
+    with fmt.indented(
+            'RegBank {{'.format(regbank.name), '},'):
+        fmt.line('name: "{}",'.format(regbank.name))
+        fmt.line('first_unit: {},'.format(regbank.first_unit))
+        fmt.line('units: {},'.format(regbank.units))
+        fmt.line(
+                'names: &[{}],'
+                .format(', '.join('"{}"'.format(n) for n in regbank.names)))
+        fmt.line('prefix: "{}",'.format(regbank.prefix))
+
+
+def gen_isa(isa, fmt):
+    # type: (TargetISA, srcgen.Formatter) -> None
+    """
+    Generate register tables for isa.
+    """
+    if not isa.regbanks:
+        print('cargo:warning={} has no register banks'.format(isa.name))
+    with fmt.indented('pub static INFO: RegInfo = RegInfo {', '};'):
+        # Bank descriptors.
+        with fmt.indented('banks: &[', '],'):
+            for regbank in isa.regbanks:
+                gen_regbank(regbank, fmt)
+
+
+def generate(isas, out_dir):
+    # type: (Sequence[TargetISA], str) -> None
+    for isa in isas:
+        fmt = srcgen.Formatter()
+        gen_isa(isa, fmt)
+        fmt.update_file('registers-{}.rs'.format(isa.name), out_dir)