Shrink the LOAD_GLOBAL caches

python · brandtbucher · Mar 11, 2023 · Feb 16, 2023 · Feb 17, 2023 · Feb 17, 2023
commit 9931a3522aedf69ff06863bd3e80e4d6b81c8387
diff --git a/Include/internal/pycore_code.h b/Include/internal/pycore_code.h
@@ -20,7 +20,7 @@ extern "C" {
 typedef struct {
     uint16_t counter;
     uint16_t index;
-    uint16_t module_keys_version[2];
+    uint16_t module_keys_version;
     uint16_t builtin_keys_version;
 } _PyLoadGlobalCache;
 

diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
diff --git a/Lib/opcode.py b/Lib/opcode.py
@@ -390,7 +390,7 @@ def pseudo_op(name, op, real_ops):
     "LOAD_GLOBAL": {
         "counter": 1,
         "index": 1,
-        "module_keys_version": 2,
+        "module_keys_version": 1,
         "builtin_keys_version": 1,
     },
     "BINARY_OP": {

diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
@@ -1078,7 +1078,7 @@ dummy_func(
             LOAD_GLOBAL_BUILTIN,
         };
 
-        inst(LOAD_GLOBAL, (unused/1, unused/1, unused/2, unused/1 -- null if (oparg & 1), v)) {
+        inst(LOAD_GLOBAL, (unused/1, unused/1, unused/1, unused/1 -- null if (oparg & 1), v)) {
             #if ENABLE_SPECIALIZATION
             _PyLoadGlobalCache *cache = (_PyLoadGlobalCache *)next_instr;
             if (ADAPTIVE_COUNTER_IS_ZERO(cache->counter)) {
@@ -1133,7 +1133,7 @@ dummy_func(
             null = NULL;
         }
 
-        inst(LOAD_GLOBAL_MODULE, (unused/1, index/1, version/2, unused/1 -- null if (oparg & 1), res)) {
+        inst(LOAD_GLOBAL_MODULE, (unused/1, index/1, version/1, unused/1 -- null if (oparg & 1), res)) {
             assert(cframe.use_tracing == 0);
             DEOPT_IF(!PyDict_CheckExact(GLOBALS()), LOAD_GLOBAL);
             PyDictObject *dict = (PyDictObject *)GLOBALS();
@@ -1147,7 +1147,7 @@ dummy_func(
             null = NULL;
         }
 
-        inst(LOAD_GLOBAL_BUILTIN, (unused/1, index/1, mod_version/2, bltn_version/1 -- null if (oparg & 1), res)) {
+        inst(LOAD_GLOBAL_BUILTIN, (unused/1, index/1, mod_version/1, bltn_version/1 -- null if (oparg & 1), res)) {
             assert(cframe.use_tracing == 0);
             DEOPT_IF(!PyDict_CheckExact(GLOBALS()), LOAD_GLOBAL);
             DEOPT_IF(!PyDict_CheckExact(BUILTINS()), LOAD_GLOBAL);

diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
diff --git a/Python/opcode_metadata.h b/Python/opcode_metadata.h
@@ -707,7 +707,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
 #endif
 
 enum Direction { DIR_NONE, DIR_READ, DIR_WRITE };
-enum InstructionFormat { INSTR_FMT_IB, INSTR_FMT_IBC, INSTR_FMT_IBC0, INSTR_FMT_IBC000, INSTR_FMT_IBC0000, INSTR_FMT_IBC00000000, INSTR_FMT_IBIB, INSTR_FMT_IX, INSTR_FMT_IXC, INSTR_FMT_IXC000 };
+enum InstructionFormat { INSTR_FMT_IB, INSTR_FMT_IBC, INSTR_FMT_IBC0, INSTR_FMT_IBC000, INSTR_FMT_IBC00000000, INSTR_FMT_IBIB, INSTR_FMT_IX, INSTR_FMT_IXC, INSTR_FMT_IXC000 };
 struct opcode_metadata {
     enum Direction dir_op1;
     enum Direction dir_op2;
@@ -789,9 +789,9 @@ const struct opcode_metadata _PyOpcode_opcode_metadata[256] = {
     [STORE_GLOBAL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [DELETE_GLOBAL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [LOAD_NAME] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
-    [LOAD_GLOBAL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC0000 },
-    [LOAD_GLOBAL_MODULE] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC0000 },
-    [LOAD_GLOBAL_BUILTIN] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC0000 },
+    [LOAD_GLOBAL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
+    [LOAD_GLOBAL_MODULE] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
+    [LOAD_GLOBAL_BUILTIN] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
     [DELETE_FAST] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [MAKE_CELL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
     [DELETE_DEREF] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },

diff --git a/Python/specialize.c b/Python/specialize.c
@@ -1144,8 +1144,12 @@ _Py_Specialize_LoadGlobal(
             SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_VERSIONS);
             goto fail;
         }
+        if (keys_version != (uint16_t)keys_version) {
+                SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
+            goto fail;
+        }
         cache->index = (uint16_t)index;
-        write_u32(cache->module_keys_version, keys_version);
+        cache->module_keys_version = (uint16_t)keys_version;
         _py_set_opcode(instr, LOAD_GLOBAL_MODULE);
         goto success;
     }
@@ -1172,6 +1176,10 @@ _Py_Specialize_LoadGlobal(
         SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_VERSIONS);
         goto fail;
     }
+    if (globals_version != (uint16_t)globals_version) {
+        SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
+        goto fail;
+    }
     uint32_t builtins_version = _PyDictKeys_GetVersionForCurrentState(builtin_keys);
     if (builtins_version == 0) {
         SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_VERSIONS);
@@ -1182,7 +1190,7 @@ _Py_Specialize_LoadGlobal(
         goto fail;
     }
     cache->index = (uint16_t)index;
-    write_u32(cache->module_keys_version, globals_version);
+    cache->module_keys_version = (uint16_t)globals_version;
     cache->builtin_keys_version = (uint16_t)builtins_version;
     _py_set_opcode(instr, LOAD_GLOBAL_BUILTIN);
     goto success;