Synchronize InstructionFormat and InstructionData.

These two enums must have identical variants. One is generated from the
instruction formats in meta/cretonne/formats.py, the other defines the contents
of an instruction.

Emit a conversion from InstructionData to InstructionFormat which also serves
to verify the correspondence. Rustc will error is the match is not complete.

meta/cretonne/__init__.py

@@ -55,6 +55,17 @@ value = OperandKind(
         operand.
         """)
 
+#: A variable-sizes list of value operands. Use for Ebb and function call
+#: arguemnts.
+args = OperandKind(
+        'args', """
+        A variable size list of `value` operands.
+
+        Use this to represent arguemtns passed to a function call, arguments
+        passed to an extended basic block, or a variable number of results
+        returned from an instruction.
+        """)
+
 
 # Instances of immediate operand types are provided in the cretonne.immediates
 # module.

meta/cretonne/formats.py

@@ -7,9 +7,11 @@ in this module.
 """
 
 
-from . import InstructionFormat, value
+from . import InstructionFormat, value, args
 from immediates import imm64, ieee32, ieee64, immvector
 
+Nullary = InstructionFormat()
+
 Unary = InstructionFormat(value)
 UnaryImm = InstructionFormat(imm64)
 UnaryIeee32 = InstructionFormat(ieee32)
@@ -20,6 +22,7 @@ Binary = InstructionFormat(value, value)
 BinaryImm = InstructionFormat(value, imm64)
 BinaryImmRev = InstructionFormat(imm64, value)
 
+Call = InstructionFormat(args, multiple_results=True)
 
 # Finally extract the names of global variables in this module.
 InstructionFormat.extract_names(globals())

meta/gen_instr.py

@@ -21,6 +21,20 @@ def gen_formats(fmt):
             fmt.line(f.name + ',')
     fmt.line()
 
+    # Emit a From<InstructionData> which also serves to verify that
+    # InstructionFormat and InstructionData are in sync.
+    with fmt.indented(
+            "impl<'a> From<&'a InstructionData> for InstructionFormat {", '}'):
+        with fmt.indented(
+                "fn from(inst: &'a InstructionData) -> InstructionFormat {",
+                '}'):
+            with fmt.indented('match *inst {', '}'):
+                for f in cretonne.InstructionFormat.all_formats:
+                    fmt.line(('InstructionData::{} {{ .. }} => ' +
+                              'InstructionFormat::{},')
+                             .format(f.name, f.name))
+    fmt.line()
+
 
 def collect_instr_groups(targets):
     seen = set()