pythonGH-137276: Don't mark uop as escaping if the escaping call is on an exit branch (pythonGH-137277)

Author: markshannon

Include/internal/pycore_opcode_metadata.h

@@ -5,7 +5,7 @@
 import re
 from typing import Optional, Callable
 
-from parser import Stmt, SimpleStmt, BlockStmt, IfStmt, WhileStmt
+from parser import Stmt, SimpleStmt, BlockStmt, IfStmt, WhileStmt, ForStmt, MacroIfStmt
 
 @dataclass
 class EscapingCall:
@@ -723,53 +723,57 @@ def visit(stmt: Stmt) -> None:
     if error is not None:
         raise analysis_error(f"Escaping call '{error.text} in condition", error)
 
+def escaping_call_in_simple_stmt(stmt: SimpleStmt, result: dict[SimpleStmt, EscapingCall]) -> None:
+    tokens = stmt.contents
+    for idx, tkn in enumerate(tokens):
+        try:
+            next_tkn = tokens[idx+1]
+        except IndexError:
+            break
+        if next_tkn.kind != lexer.LPAREN:
+            continue
+        if tkn.kind == lexer.IDENTIFIER:
+            if tkn.text.upper() == tkn.text:
+                # simple macro
+                continue
+            #if not tkn.text.startswith(("Py", "_Py", "monitor")):
+            #    continue
+            if tkn.text.startswith(("sym_", "optimize_", "PyJitRef")):
+                # Optimize functions
+                continue
+            if tkn.text.endswith("Check"):
+                continue
+            if tkn.text.startswith("Py_Is"):
+                continue
+            if tkn.text.endswith("CheckExact"):
+                continue
+            if tkn.text in NON_ESCAPING_FUNCTIONS:
+                continue
+        elif tkn.kind == "RPAREN":
+            prev = tokens[idx-1]
+            if prev.text.endswith("_t") or prev.text == "*" or prev.text == "int":
+                #cast
+                continue
+        elif tkn.kind != "RBRACKET":
+            continue
+        if tkn.text in ("PyStackRef_CLOSE", "PyStackRef_XCLOSE"):
+            if len(tokens) <= idx+2:
+                raise analysis_error("Unexpected end of file", next_tkn)
+            kills = tokens[idx+2]
+            if kills.kind != "IDENTIFIER":
+                raise analysis_error(f"Expected identifier, got '{kills.text}'", kills)
+        else:
+            kills = None
+        result[stmt] = EscapingCall(stmt, tkn, kills)
+
+
 def find_escaping_api_calls(instr: parser.CodeDef) -> dict[SimpleStmt, EscapingCall]:
     result: dict[SimpleStmt, EscapingCall] = {}
 
     def visit(stmt: Stmt) -> None:
         if not isinstance(stmt, SimpleStmt):
             return
-        tokens = stmt.contents
-        for idx, tkn in enumerate(tokens):
-            try:
-                next_tkn = tokens[idx+1]
-            except IndexError:
-                break
-            if next_tkn.kind != lexer.LPAREN:
-                continue
-            if tkn.kind == lexer.IDENTIFIER:
-                if tkn.text.upper() == tkn.text:
-                    # simple macro
-                    continue
-                #if not tkn.text.startswith(("Py", "_Py", "monitor")):
-                #    continue
-                if tkn.text.startswith(("sym_", "optimize_", "PyJitRef")):
-                    # Optimize functions
-                    continue
-                if tkn.text.endswith("Check"):
-                    continue
-                if tkn.text.startswith("Py_Is"):
-                    continue
-                if tkn.text.endswith("CheckExact"):
-                    continue
-                if tkn.text in NON_ESCAPING_FUNCTIONS:
-                    continue
-            elif tkn.kind == "RPAREN":
-                prev = tokens[idx-1]
-                if prev.text.endswith("_t") or prev.text == "*" or prev.text == "int":
-                    #cast
-                    continue
-            elif tkn.kind != "RBRACKET":
-                continue
-            if tkn.text in ("PyStackRef_CLOSE", "PyStackRef_XCLOSE"):
-                if len(tokens) <= idx+2:
-                    raise analysis_error("Unexpected end of file", next_tkn)
-                kills = tokens[idx+2]
-                if kills.kind != "IDENTIFIER":
-                    raise analysis_error(f"Expected identifier, got '{kills.text}'", kills)
-            else:
-                kills = None
-            result[stmt] = EscapingCall(stmt, tkn, kills)
+        escaping_call_in_simple_stmt(stmt, result)
 
     instr.block.accept(visit)
     check_escaping_calls(instr, result)
@@ -822,6 +826,60 @@ def stack_effect_only_peeks(instr: parser.InstDef) -> bool:
     )
 
 
+def stmt_is_simple_exit(stmt: Stmt) -> bool:
+    if not isinstance(stmt, SimpleStmt):
+        return False
+    tokens = stmt.contents
+    if len(tokens) < 4:
+        return False
+    return (
+        tokens[0].text in ("ERROR_IF", "DEOPT_IF", "EXIT_IF")
+        and
+        tokens[1].text == "("
+        and
+        tokens[2].text in ("true", "1")
+        and
+        tokens[3].text == ")"
+    )
+
+
+def stmt_list_escapes(stmts: list[Stmt]) -> bool:
+    if not stmts:
+        return False
+    if stmt_is_simple_exit(stmts[-1]):
+        return False
+    for stmt in stmts:
+        if stmt_escapes(stmt):
+            return True
+    return False
+
+
+def stmt_escapes(stmt: Stmt) -> bool:
+    if isinstance(stmt, BlockStmt):
+        return stmt_list_escapes(stmt.body)
+    elif isinstance(stmt, SimpleStmt):
+        for tkn in stmt.contents:
+            if tkn.text == "DECREF_INPUTS":
+                return True
+        d: dict[SimpleStmt, EscapingCall] = {}
+        escaping_call_in_simple_stmt(stmt, d)
+        return bool(d)
+    elif isinstance(stmt, IfStmt):
+        if stmt.else_body and stmt_escapes(stmt.else_body):
+            return True
+        return stmt_escapes(stmt.body)
+    elif isinstance(stmt, MacroIfStmt):
+        if stmt.else_body and stmt_list_escapes(stmt.else_body):
+            return True
+        return stmt_list_escapes(stmt.body)
+    elif isinstance(stmt, ForStmt):
+        return stmt_escapes(stmt.body)
+    elif isinstance(stmt, WhileStmt):
+        return stmt_escapes(stmt.body)
+    else:
+        assert False, "Unexpected statement type"
+
+
 def compute_properties(op: parser.CodeDef) -> Properties:
     escaping_calls = find_escaping_api_calls(op)
     has_free = (
@@ -843,7 +901,7 @@ def compute_properties(op: parser.CodeDef) -> Properties:
         )
     error_with_pop = has_error_with_pop(op)
     error_without_pop = has_error_without_pop(op)
-    escapes = bool(escaping_calls) or variable_used(op, "DECREF_INPUTS")
+    escapes = stmt_escapes(op.block)
     pure = False if isinstance(op, parser.LabelDef) else "pure" in op.annotations
     no_save_ip = False if isinstance(op, parser.LabelDef) else "no_save_ip" in op.annotations
     return Properties(