bpo-44525: Copy free variables in bytecode to allow calls to inner functions to be specialized (GH-29595)

* Make internal APIs that take PyFrameConstructor take a PyFunctionObject instead.

* Add reference to function to frame, borrow references to builtins and globals.

* Add COPY_FREE_VARS instruction to allow specialization of calls to inner functions.

1 files changed, 19 insertions, 2 deletions

diff --git a/Python/compile.c b/Python/compile.c
index 40bd1fd..87de7ba 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1171,6 +1171,7 @@ stack_effect(int opcode, int oparg, int jump)
 
         /* Closures */
         case MAKE_CELL:
+        case COPY_FREE_VARS:
             return 0;
         case LOAD_CLOSURE:
             return 1;
@@ -7611,7 +7612,7 @@ insert_instruction(basicblock *block, int pos, struct instr *instr) {
 
 static int
 insert_prefix_instructions(struct compiler *c, basicblock *entryblock,
-                           int *fixed)
+                           int *fixed, int nfreevars)
 {
 
     int flags = compute_code_flags(c);
@@ -7684,6 +7685,22 @@ insert_prefix_instructions(struct compiler *c, basicblock *entryblock,
         }
     }
 
+    if (nfreevars) {
+        struct instr copy_frees = {
+            .i_opcode = COPY_FREE_VARS,
+            .i_oparg = nfreevars,
+            .i_lineno = -1,
+            .i_col_offset = -1,
+            .i_end_lineno = -1,
+            .i_end_col_offset = -1,
+            .i_target = NULL,
+        };
+        if (insert_instruction(entryblock, 0, &copy_frees) < 0) {
+            return -1;
+        }
+
+    }
+
     return 0;
 }
 
@@ -7818,7 +7835,7 @@ assemble(struct compiler *c, int addNone)
     }
 
     // This must be called before fix_cell_offsets().
-    if (insert_prefix_instructions(c, entryblock, cellfixedoffsets)) {
+    if (insert_prefix_instructions(c, entryblock, cellfixedoffsets, nfreevars)) {
         goto error;
     }