bpo-44187: Quickening infrastructure (GH-26264)

* Add co_firstinstr field to code object.

* Implement barebones quickening.

* Use non-quickened bytecode when tracing.

* Add NEWS item

* Add new file to Windows build.

* Don't specialize instructions with EXTENDED_ARG.

1 files changed, 11 insertions, 2 deletions

diff --git a/Include/cpython/code.h b/Include/cpython/code.h
index 5c0fae4..98d728b 100644
--- a/Include/cpython/code.h
+++ b/Include/cpython/code.h
@@ -7,9 +7,11 @@ typedef uint16_t _Py_CODEUNIT;
 #ifdef WORDS_BIGENDIAN
 #  define _Py_OPCODE(word) ((word) >> 8)
 #  define _Py_OPARG(word) ((word) & 255)
+#  define _Py_MAKECODEUNIT(opcode, oparg) (((opcode)<<8)|(oparg))
 #else
 #  define _Py_OPCODE(word) ((word) & 255)
 #  define _Py_OPARG(word) ((word) >> 8)
+#  define _Py_MAKECODEUNIT(opcode, oparg) ((opcode)|((oparg)<<8))
 #endif
 
 typedef struct _PyOpcache _PyOpcache;
@@ -43,16 +45,20 @@ struct PyCodeObject {
     /* These fields are set with provided values on new code objects. */
 
     // The hottest fields (in the eval loop) are grouped here at the top.
-    PyObject *co_code;          /* instruction opcodes */
     PyObject *co_consts;        /* list (constants used) */
     PyObject *co_names;         /* list of strings (names used) */
+    _Py_CODEUNIT *co_firstinstr; /* Pointer to first instruction, used for quickening */
+    PyObject *co_exceptiontable; /* Byte string encoding exception handling table */
     int co_flags;               /* CO_..., see below */
+    int co_warmup;              /* Warmup counter for quickening */
+
     // The rest are not so impactful on performance.
     int co_argcount;            /* #arguments, except *args */
     int co_posonlyargcount;     /* #positional only arguments */
     int co_kwonlyargcount;      /* #keyword only arguments */
     int co_stacksize;           /* #entries needed for evaluation stack */
     int co_firstlineno;         /* first source line number */
+    PyObject *co_code;          /* instruction opcodes */
     PyObject *co_varnames;      /* tuple of strings (local variable names) */
     PyObject *co_cellvars;      /* tuple of strings (cell variable names) */
     PyObject *co_freevars;      /* tuple of strings (free variable names) */
@@ -60,7 +66,6 @@ struct PyCodeObject {
     PyObject *co_name;          /* unicode (name, for reference) */
     PyObject *co_linetable;     /* string (encoding addr<->lineno mapping) See
                                    Objects/lnotab_notes.txt for details. */
-    PyObject *co_exceptiontable; /* Byte string encoding exception handling table */
 
     /* These fields are set with computed values on new code objects. */
 
@@ -78,6 +83,10 @@ struct PyCodeObject {
        Type is a void* to keep the format private in codeobject.c to force
        people to go through the proper APIs. */
     void *co_extra;
+    /* Quickened instructions and cache, or NULL
+     This should be treated as opaque by all code except the specializer and
+     interpreter. */
+    union _cache_or_instruction *co_quickened;
 
     /* Per opcodes just-in-time cache
      *