Extract InstructionFlags etc. into flags.py

python · gvanrossum · Jul 24, 2023 · Jul 22, 2023 · Jul 23, 2023 · Jul 23, 2023
commit 4bc2c5c4ae7bc7cb475a7157ca4ceef6a83e8f2f
@@ -0,0 +1,102 @@
+import dataclasses
+
+from formatting import Formatter
+import lexer as lx
+import parsing
+
+
+@dataclasses.dataclass
+class InstructionFlags:
+    """Construct and manipulate instruction flags"""
+
+    HAS_ARG_FLAG: bool
+    HAS_CONST_FLAG: bool
+    HAS_NAME_FLAG: bool
+    HAS_JUMP_FLAG: bool
+    HAS_FREE_FLAG: bool
+    HAS_LOCAL_FLAG: bool
+
+    def __post_init__(self):
+        self.bitmask = {name: (1 << i) for i, name in enumerate(self.names())}
+
+    @staticmethod
+    def fromInstruction(instr: parsing.Node):
+
+        has_free = (
+            variable_used(instr, "PyCell_New")
+            or variable_used(instr, "PyCell_GET")
+            or variable_used(instr, "PyCell_SET")
+        )
+
+        return InstructionFlags(
+            HAS_ARG_FLAG=variable_used(instr, "oparg"),
+            HAS_CONST_FLAG=variable_used(instr, "FRAME_CO_CONSTS"),
+            HAS_NAME_FLAG=variable_used(instr, "FRAME_CO_NAMES"),
+            HAS_JUMP_FLAG=variable_used(instr, "JUMPBY"),
+            HAS_FREE_FLAG=has_free,
+            HAS_LOCAL_FLAG=(
+                variable_used(instr, "GETLOCAL") or variable_used(instr, "SETLOCAL")
+            )
+            and not has_free,
+        )
+
+    @staticmethod
+    def newEmpty():
+        return InstructionFlags(False, False, False, False, False, False)
+
+    def add(self, other: "InstructionFlags") -> None:
+        for name, value in dataclasses.asdict(other).items():
+            if value:
+                setattr(self, name, value)
+
+    def names(self, value=None):
+        if value is None:
+            return dataclasses.asdict(self).keys()
+        return [n for n, v in dataclasses.asdict(self).items() if v == value]
+
+    def bitmap(self) -> int:
+        flags = 0
+        for name in self.names():
+            if getattr(self, name):
+                flags |= self.bitmask[name]
+        return flags
+
+    @classmethod
+    def emit_macros(cls, out: Formatter):
+        flags = cls.newEmpty()
+        for name, value in flags.bitmask.items():
+            out.emit(f"#define {name} ({value})")
+
+        for name, value in flags.bitmask.items():
+            out.emit(
+                f"#define OPCODE_{name[:-len('_FLAG')]}(OP) "
+                f"(_PyOpcode_opcode_metadata[OP].flags & ({name}))"
+            )
+
+
+def variable_used(node: parsing.Node, name: str) -> bool:
+    """Determine whether a variable with a given name is used in a node."""
+    return any(
+        token.kind == "IDENTIFIER" and token.text == name for token in node.tokens
+    )
+
+
+def variable_used_unspecialized(node: parsing.Node, name: str) -> bool:
+    """Like variable_used(), but skips #if ENABLE_SPECIALIZATION blocks."""
+    tokens: list[lx.Token] = []
+    skipping = False
+    for i, token in enumerate(node.tokens):
+        if token.kind == "MACRO":
+            text = "".join(token.text.split())
+            # TODO: Handle nested #if
+            if text == "#if":
+                if (
+                    i + 1 < len(node.tokens)
+                    and node.tokens[i + 1].text == "ENABLE_SPECIALIZATION"
+                ):
+                    skipping = True
+            elif text in ("#else", "#endif"):
+                skipping = False
+        if not skipping:
+            tokens.append(token)
+    return any(token.kind == "IDENTIFIER" and token.text == name for token in tokens)
@@ -1,5 +1,5 @@
-"""Generate the main interpreter switch.
 
+"""Generate the main interpreter switch.
 Reads the instruction definitions from bytecodes.c.
 Writes the cases to generated_cases.c.h, which is #included in ceval.c.
 """
@@ -13,9 +13,6 @@
 import sys
 import typing
 
-import lexer as lx
-import parsing
-from parsing import StackEffect
 from formatting import (
     Formatter,
     UNUSED,
@@ -24,6 +21,10 @@
     prettify_filename,
     string_effect_size,
 )
+from flags import InstructionFlags, variable_used, variable_used_unspecialized
+import lexer as lx
+import parsing
+from parsing import StackEffect
 
 
 HERE = os.path.dirname(__file__)
@@ -92,72 +93,6 @@
 )
 
 
-@dataclasses.dataclass
-class InstructionFlags:
-    """Construct and manipulate instruction flags"""
-
-    HAS_ARG_FLAG: bool
-    HAS_CONST_FLAG: bool
-    HAS_NAME_FLAG: bool
-    HAS_JUMP_FLAG: bool
-    HAS_FREE_FLAG: bool
-    HAS_LOCAL_FLAG: bool
-
-    def __post_init__(self):
-        self.bitmask = {
-            name : (1 << i) for i, name in enumerate(self.names())
-        }
-
-    @staticmethod
-    def fromInstruction(instr: "AnyInstruction"):
-
-        has_free = (variable_used(instr, "PyCell_New") or
-                    variable_used(instr, "PyCell_GET") or
-                    variable_used(instr, "PyCell_SET"))
-
-        return InstructionFlags(
-            HAS_ARG_FLAG=variable_used(instr, "oparg"),
-            HAS_CONST_FLAG=variable_used(instr, "FRAME_CO_CONSTS"),
-            HAS_NAME_FLAG=variable_used(instr, "FRAME_CO_NAMES"),
-            HAS_JUMP_FLAG=variable_used(instr, "JUMPBY"),
-            HAS_FREE_FLAG=has_free,
-            HAS_LOCAL_FLAG=(variable_used(instr, "GETLOCAL") or
-                            variable_used(instr, "SETLOCAL")) and
-                            not has_free,
-        )
-
-    @staticmethod
-    def newEmpty():
-        return InstructionFlags(False, False, False, False, False, False)
-
-    def add(self, other: "InstructionFlags") -> None:
-        for name, value in dataclasses.asdict(other).items():
-            if value:
-                setattr(self, name, value)
-
-    def names(self, value=None):
-        if value is None:
-            return dataclasses.asdict(self).keys()
-        return [n for n, v in dataclasses.asdict(self).items() if v == value]
-
-    def bitmap(self) -> int:
-        flags = 0
-        for name in self.names():
-            if getattr(self, name):
-                flags |= self.bitmask[name]
-        return flags
-
-    @classmethod
-    def emit_macros(cls, out: Formatter):
-        flags = cls.newEmpty()
-        for name, value in flags.bitmask.items():
-            out.emit(f"#define {name} ({value})");
-
-        for name, value in flags.bitmask.items():
-            out.emit(
-                f"#define OPCODE_{name[:-len('_FLAG')]}(OP) "
-                f"(_PyOpcode_opcode_metadata[OP].flags & ({name}))")
-
 
 @dataclasses.dataclass
 class ActiveCacheEffect:
@@ -1504,34 +1439,6 @@ def always_exits(lines: list[str]) -> bool:
     )
 
 
-def variable_used(node: parsing.Node, name: str) -> bool:
-    """Determine whether a variable with a given name is used in a node."""
-    return any(
-        token.kind == "IDENTIFIER" and token.text == name for token in node.tokens
-    )
-
-
-def variable_used_unspecialized(node: parsing.Node, name: str) -> bool:
-    """Like variable_used(), but skips #if ENABLE_SPECIALIZATION blocks."""
-    tokens: list[lx.Token] = []
-    skipping = False
-    for i, token in enumerate(node.tokens):
-        if token.kind == "MACRO":
-            text = "".join(token.text.split())
-            # TODO: Handle nested #if
-            if text == "#if":
-                if (
-                    i + 1 < len(node.tokens)
-                    and node.tokens[i + 1].text == "ENABLE_SPECIALIZATION"
-                ):
-                    skipping = True
-            elif text in ("#else", "#endif"):
-                skipping = False
-        if not skipping:
-            tokens.append(token)
-    return any(token.kind == "IDENTIFIER" and token.text == name for token in tokens)
-
-
 def main():
     """Parse command line, parse input, analyze, write output."""
     args = arg_parser.parse_args()  # Prints message and sys.exit(2) on error