Fix alignment

Author: pablogsal

Include/internal/pycore_interp_structs.h

@@ -73,6 +73,7 @@ struct trampoline_api_st {
     int (*free_state)(void* state);
     void *state;
     Py_ssize_t code_padding;
+    Py_ssize_t code_alignment;
 };
 #endif
 

Python/perf_trampoline.c

@@ -230,6 +230,7 @@ perf_map_init_state(void)
 {
     PyUnstable_PerfMapState_Init();
     trampoline_api.code_padding = 0;
+    trampoline_api.code_alignment = 32;
     perf_trampoline_type = PERF_TRAMPOLINE_TYPE_MAP;
     return NULL;
 }
@@ -291,7 +292,9 @@ new_code_arena(void)
     void *start = &_Py_trampoline_func_start;
     void *end = &_Py_trampoline_func_end;
     size_t code_size = end - start;
-    size_t chunk_size = round_up(code_size + trampoline_api.code_padding, 16);
+    size_t unaligned_size = code_size + trampoline_api.code_padding;
+    size_t chunk_size = round_up(unaligned_size, trampoline_api.code_alignment);
+    assert(chunk_size % trampoline_api.code_alignment == 0);
     // TODO: Check the effect of alignment of the code chunks. Initial investigation
     // showed that this has no effect on performance in x86-64 or aarch64 and the current
     // version has the advantage that the unwinder in GDB can unwind across JIT-ed code.
@@ -356,7 +359,9 @@ static inline py_trampoline
 code_arena_new_code(code_arena_t *code_arena)
 {
     py_trampoline trampoline = (py_trampoline)code_arena->current_addr;
-    size_t total_code_size = round_up(code_arena->code_size + trampoline_api.code_padding, 16);
+    size_t total_code_size = round_up(code_arena->code_size + trampoline_api.code_padding,
+                                  trampoline_api.code_alignment);
+    assert(total_code_size % trampoline_api.code_alignment == 0);
     code_arena->size_left -= total_code_size;
     code_arena->current_addr += total_code_size;
     return trampoline;