Fix constness and rename hotness

markshannon · Feb 20, 2024 · Jan 10, 2024 · Jan 11, 2024 · Jan 11, 2024 · Jan 11, 2024
commit 5c8f0bd0ed81e59425dcfad575b72bfa26632905
diff --git a/Include/cpython/optimizer.h b/Include/cpython/optimizer.h
@@ -38,13 +38,13 @@ typedef struct {
 
 typedef struct _exit_data {
     uint32_t target;
-    int16_t hotness;
+    int16_t temperature;
     struct _PyExecutorObject *executor;
 } _PyExitData;
 
 typedef struct _PyExecutorObject {
     PyObject_VAR_HEAD
-    _PyUOpInstruction *trace;
+    const _PyUOpInstruction *trace;
     _PyVMData vm_data; /* Used by the VM, but opaque to the optimizer */
     uint32_t exit_count;
     uint32_t code_size;

@@ -4087,11 +4087,11 @@ dummy_func(
             TIER_TWO_ONLY
             assert(current_executor->trace[0].opcode != _COLD_EXIT);
             _PyExitData *exit = &current_executor->exits[oparg];
-            exit->hotness++;
+            exit->temperature++;
             assert(exit->executor->trace[0].opcode == _COLD_EXIT);
             PyCodeObject *code = _PyFrame_GetCode(frame);
             _Py_CODEUNIT *target = _PyCode_CODE(code) + exit->target;
-            if (exit->hotness < 0) {
+            if (exit->temperature < 0) {
                 next_instr = target;
                 Py_DECREF(current_executor);
                 current_executor = NULL;
@@ -4104,7 +4104,7 @@ dummy_func(
             } else {
                 int optimized = _PyOptimizer_Optimize(frame, target, stack_pointer, &executor);
                 if (optimized <= 0) {
-                    exit->hotness = -10000; /* Choose a better number */
+                    exit->temperature = -10000; /* Choose a better number */
                     Py_DECREF(current_executor);
                     current_executor = NULL;
                     next_instr = target;

@@ -745,7 +745,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
 
     _Py_CODEUNIT *next_instr;
     PyObject **stack_pointer;
-    _PyUOpInstruction *next_uop = NULL;
+    const _PyUOpInstruction *next_uop = NULL;
 
 
 start_frame:
@@ -1081,8 +1081,8 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
     UOP_STAT_INC(uopcode, miss);
     uint32_t exit_id = next_uop[-1].target;
     _PyExitData *exit = &current_executor->exits[exit_id];
-    DPRINTF(2, "SIDE EXIT: [UOp %d (%s), oparg %d, operand %" PRIu64 ", exit %u, hotness %d, target %d -> %s]\n",
-            uopcode, _PyUOpName(uopcode), next_uop[-1].oparg, next_uop[-1].operand, exit_id, exit->hotness, exit->target,
+    DPRINTF(2, "SIDE EXIT: [UOp %d (%s), oparg %d, operand %" PRIu64 ", exit %u, temp %d, target %d -> %s]\n",
+            uopcode, _PyUOpName(uopcode), next_uop[-1].oparg, next_uop[-1].operand, exit_id, exit->temperature, exit->target,
             _PyOpcode_OpName[_PyCode_CODE(_PyFrame_GetCode(frame))[exit->target].op.code]);
     Py_INCREF(exit->executor);
     next_uop = exit->executor->trace;

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
@@ -812,7 +812,7 @@ PyTypeObject _ColdExit_Type = {
     .tp_methods = executor_methods,
 };
 
-static _PyColdExitObject COLD_EXITS[UOP_MAX_TRACE_LENGTH];
+static const _PyColdExitObject COLD_EXITS[UOP_MAX_TRACE_LENGTH];
 
 static _PyExecutorObject *
 allocate_executor(int exit_count, int length)
@@ -855,38 +855,38 @@ make_executor_from_uops(_PyUOpInstruction *buffer, _PyBloomFilter *dependencies)
     /* Initialize exits */
     for (int i = 0; i < exit_count; i++) {
         executor->exits[i].executor = (_PyExecutorObject *)&COLD_EXITS[i];
-        executor->exits[i].hotness = -67;
+        executor->exits[i].temperature = -67;
     }
     int next_exit = exit_count-1;
-    int dest = length;
+    _PyUOpInstruction *dest = (_PyUOpInstruction *)&executor->trace[length];
     /* Scan backwards, so that we see the destinations of jumps before the jumps themselves. */
     for (int i = UOP_MAX_TRACE_LENGTH-1; i >= 0; i--) {
         if (!BIT_IS_SET(used, i)) {
             continue;
         }
-        executor->trace[dest] = buffer[i];
+        *dest = buffer[i];
         int opcode = buffer[i].opcode;
         if (opcode == _POP_JUMP_IF_FALSE ||
             opcode == _POP_JUMP_IF_TRUE)
         {
             /* The oparg of the target will already have been set to its new offset */
-            int oparg = executor->trace[dest].oparg;
-            executor->trace[dest].oparg = buffer[oparg].oparg;
+            int oparg = dest->oparg;
+            dest->oparg = buffer[oparg].oparg;
         }
         if (_PyUop_Flags[opcode] & HAS_EXIT_FLAG) {
             executor->exits[next_exit].target = buffer[i].target;
-            executor->trace[dest].target = next_exit;
+            dest->target = next_exit;
             next_exit--;
         }
         /* Set the oparg to be the destination offset,
          * so that we can set the oparg of earlier jumps correctly. */
-        buffer[i].oparg = dest;
+        buffer[i].oparg = dest - executor->trace;
         dest--;
     }
     assert(next_exit == -1);
-    assert(dest == 0);
-    executor->trace[0].opcode = _START_EXECUTOR;
-    executor->trace[0].operand = (uintptr_t)executor;
+    assert(dest == executor->trace);
+    dest->opcode = _START_EXECUTOR;
+    dest->operand = (uintptr_t)executor;
     _Py_ExecutorInit(executor, dependencies);
 #ifdef Py_DEBUG
     char *python_lltrace = Py_GETENV("PYTHON_LLTRACE");
@@ -1247,7 +1247,7 @@ print("};")
 
 static_assert(UOP_MAX_TRACE_LENGTH == 512, "COLD_EXITS must be regenerated");
 
-static _PyColdExitObject COLD_EXITS[] = {
+static const _PyColdExitObject COLD_EXITS[] = {
     [0] = { .base = { PyVarObject_HEAD_INIT(&_ColdExit_Type, 0) .vm_data = { 0 }, .trace = &COLD_EXITS[0].uop }, .uop.opcode = _COLD_EXIT, .uop.oparg = 0 },
     [1] = { .base = { PyVarObject_HEAD_INIT(&_ColdExit_Type, 0) .vm_data = { 0 }, .trace = &COLD_EXITS[1].uop }, .uop.opcode = _COLD_EXIT, .uop.oparg = 1 },
     [2] = { .base = { PyVarObject_HEAD_INIT(&_ColdExit_Type, 0) .vm_data = { 0 }, .trace = &COLD_EXITS[2].uop }, .uop.opcode = _COLD_EXIT, .uop.oparg = 2 },

@@ -318,6 +318,7 @@ def clean_lines(text):
     _abs('Objects/stringlib/unicode_format.h'): (10_000, 400),
     _abs('Objects/typeobject.c'): (35_000, 200),
     _abs('Python/compile.c'): (20_000, 500),
+    _abs('Python/optimizer.c'): (100_000, 5_000),
     _abs('Python/parking_lot.c'): (40_000, 1000),
     _abs('Python/pylifecycle.c'): (500_000, 5000),
     _abs('Python/pystate.c'): (500_000, 5000),