compute stack effect of BUILD_MAP correctly (closes #25060)

benjaminp · benjaminp · commit b6855150397a · 2015-09-10T21:02:39.000-07:00
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -14,6 +14,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #25060: Correctly compute stack usage of the BUILD_MAP opcode.
+
 - Issue #24857: Comparing call_args to a long sequence now correctly returns a
   boolean result instead of raising an exception.  Patch by A Kaptur.
 
diff --git a/Python/compile.c b/Python/compile.c
@@ -985,7 +985,7 @@ PyCompile_OpcodeStackEffect(int opcode, int oparg)
         case BUILD_MAP_UNPACK_WITH_CALL:
             return 1 - (oparg & 0xFF);
         case BUILD_MAP:
-            return 1;
+            return 1 - 2*oparg;
         case LOAD_ATTR:
             return 0;
         case COMPARE_OP:
diff --git a/Python/importlib_external.h b/Python/importlib_external.h
@@ -1395,7 +1395,7 @@ const unsigned char _Py_M__importlib_external[] = {
     32,83,111,117,114,99,101,76,111,97,100,101,114,32,117,115,
     105,110,103,32,116,104,101,32,102,105,108,101,32,115,121,115,
     116,101,109,46,99,2,0,0,0,0,0,0,0,3,0,0,
-    0,5,0,0,0,67,0,0,0,115,34,0,0,0,116,0,
+    0,4,0,0,0,67,0,0,0,115,34,0,0,0,116,0,
     0,124,1,0,131,1,0,125,2,0,100,1,0,124,2,0,
     106,1,0,100,2,0,124,2,0,106,2,0,105,2,0,83,
     41,3,122,33,82,101,116,117,114,110,32,116,104,101,32,109,
