GH-113464: Add a JIT backend for tier 2 (GH-113465)

Add an option (--enable-experimental-jit for configure-based builds or --experimental-jit for PCbuild-based ones) to build an *experimental* just-in-time compiler, based on copy-and-patch (https://fredrikbk.com/publications/copy-and-patch.pdf). See Tools/jit/README.md for more information on how to install the required build-time tooling.
2025-08-04 08:59:19 +00:00 · 2024-01-28 18:48:48 -08:00 · 2024-01-28 18:48:48 -08:00 · f6d9e5926b
commit f6d9e5926b
parent f7c05d7ad3
29 changed files with 1738 additions and 5 deletions
--- a/Tools/jit/template.c
+++ b/Tools/jit/template.c
@ -0,0 +1,98 @@
+#include "Python.h"
+
+#include "pycore_call.h"
+#include "pycore_ceval.h"
+#include "pycore_dict.h"
+#include "pycore_emscripten_signal.h"
+#include "pycore_intrinsics.h"
+#include "pycore_jit.h"
+#include "pycore_long.h"
+#include "pycore_opcode_metadata.h"
+#include "pycore_opcode_utils.h"
+#include "pycore_range.h"
+#include "pycore_setobject.h"
+#include "pycore_sliceobject.h"
+
+#include "ceval_macros.h"
+
+#undef CURRENT_OPARG
+#define CURRENT_OPARG() (_oparg)
+
+#undef CURRENT_OPERAND
+#define CURRENT_OPERAND() (_operand)
+
+#undef DEOPT_IF
+#define DEOPT_IF(COND, INSTNAME) \
+    do {                         \
+        if ((COND)) {            \
+            goto deoptimize;     \
+        }                        \
+    } while (0)
+
+#undef ENABLE_SPECIALIZATION
+#define ENABLE_SPECIALIZATION (0)
+
+#undef GOTO_ERROR
+#define GOTO_ERROR(LABEL)        \
+    do {                         \
+        goto LABEL ## _tier_two; \
+    } while (0)
+
+#undef LOAD_IP
+#define LOAD_IP(UNUSED) \
+    do {                \
+    } while (0)
+
+#define PATCH_VALUE(TYPE, NAME, ALIAS)  \
+    extern void ALIAS;                  \
+    TYPE NAME = (TYPE)(uint64_t)&ALIAS;
+
+#define PATCH_JUMP(ALIAS)                                    \
+    extern void ALIAS;                                       \
+    __attribute__((musttail))                                \
+    return ((jit_func)&ALIAS)(frame, stack_pointer, tstate);
+
+_Py_CODEUNIT *
+_JIT_ENTRY(_PyInterpreterFrame *frame, PyObject **stack_pointer, PyThreadState *tstate)
+{
+    // Locals that the instruction implementations expect to exist:
+    PATCH_VALUE(_PyExecutorObject *, current_executor, _JIT_EXECUTOR)
+    int oparg;
+    int opcode = _JIT_OPCODE;
+    _PyUOpInstruction *next_uop;
+    // Other stuff we need handy:
+    PATCH_VALUE(uint16_t, _oparg, _JIT_OPARG)
+    PATCH_VALUE(uint64_t, _operand, _JIT_OPERAND)
+    PATCH_VALUE(uint32_t, _target, _JIT_TARGET)
+    // The actual instruction definitions (only one will be used):
+    if (opcode == _JUMP_TO_TOP) {
+        CHECK_EVAL_BREAKER();
+        PATCH_JUMP(_JIT_TOP);
+    }
+    switch (opcode) {
+#include "executor_cases.c.h"
+        default:
+            Py_UNREACHABLE();
+    }
+    PATCH_JUMP(_JIT_CONTINUE);
+    // Labels that the instruction implementations expect to exist:
+unbound_local_error_tier_two:
+    _PyEval_FormatExcCheckArg(
+        tstate, PyExc_UnboundLocalError, UNBOUNDLOCAL_ERROR_MSG,
+        PyTuple_GetItem(_PyFrame_GetCode(frame)->co_localsplusnames, oparg));
+    goto error_tier_two;
+pop_4_error_tier_two:
+    STACK_SHRINK(1);
+pop_3_error_tier_two:
+    STACK_SHRINK(1);
+pop_2_error_tier_two:
+    STACK_SHRINK(1);
+pop_1_error_tier_two:
+    STACK_SHRINK(1);
+error_tier_two:
+    _PyFrame_SetStackPointer(frame, stack_pointer);
+    return NULL;
+deoptimize:
+    _PyFrame_SetStackPointer(frame, stack_pointer);
+    return _PyCode_CODE(_PyFrame_GetCode(frame)) + _target;
+}