GH-111485: Increment `next_instr` consistently at the start of the instruction. (GH-111486)

3 files changed, 13 insertions, 6 deletions

diff --git a/Tools/cases_generator/analysis.py b/Tools/cases_generator/analysis.py
index 53f715d..180bd01 100644
--- a/Tools/cases_generator/analysis.py
+++ b/Tools/cases_generator/analysis.py
@@ -432,7 +432,6 @@ class Analyzer:
             "LOAD_FAST_LOAD_FAST",
             "LOAD_CONST_LOAD_FAST",
             "STORE_FAST_STORE_FAST",
-            "_BINARY_OP_INPLACE_ADD_UNICODE",
             "POP_JUMP_IF_TRUE",
             "POP_JUMP_IF_FALSE",
             "_ITER_JUMP_LIST",
diff --git a/Tools/cases_generator/instructions.py b/Tools/cases_generator/instructions.py
index c6b5516..e9ed2a8 100644
--- a/Tools/cases_generator/instructions.py
+++ b/Tools/cases_generator/instructions.py
@@ -61,6 +61,7 @@ class Instruction:
     # Computed by constructor
     always_exits: str  # If the block always exits, its last line; else ""
     has_deopt: bool
+    needs_this_instr: bool
     cache_offset: int
     cache_effects: list[parsing.CacheEffect]
     input_effects: list[StackEffect]
@@ -87,6 +88,7 @@ class Instruction:
             effect for effect in inst.inputs if isinstance(effect, parsing.CacheEffect)
         ]
         self.cache_offset = sum(c.size for c in self.cache_effects)
+        self.needs_this_instr = variable_used(self.inst, "this_instr") or any(c.name != UNUSED for c in self.cache_effects)
         self.input_effects = [
             effect for effect in inst.inputs if isinstance(effect, StackEffect)
         ]
@@ -164,7 +166,8 @@ class Instruction:
                 func = f"read_u{bits}"
             if tier == TIER_ONE:
                 out.emit(
-                    f"{typ}{ceffect.name} = {func}(&next_instr[{active.offset}].cache);"
+                    f"{typ}{ceffect.name} = "
+                    f"{func}(&this_instr[{active.offset + 1}].cache);"
                 )
             else:
                 out.emit(f"{typ}{ceffect.name} = ({typ.strip()})operand;")
diff --git a/Tools/cases_generator/stacking.py b/Tools/cases_generator/stacking.py
index 69a6c10..123e38c 100644
--- a/Tools/cases_generator/stacking.py
+++ b/Tools/cases_generator/stacking.py
@@ -365,8 +365,17 @@ def write_macro_instr(mac: MacroInstruction, out: Formatter) -> None:
     ]
     out.emit("")
     with out.block(f"TARGET({mac.name})"):
+        needs_this = any(part.instr.needs_this_instr for part in parts)
+        if needs_this and not mac.predicted:
+            out.emit(f"_Py_CODEUNIT *this_instr = frame->instr_ptr = next_instr;")
+        else:
+            out.emit(f"frame->instr_ptr = next_instr;")
+        out.emit(f"next_instr += {mac.cache_offset+1};")
+        out.emit(f"INSTRUCTION_STATS({mac.name});")
         if mac.predicted:
             out.emit(f"PREDICTED({mac.name});")
+            if needs_this:
+                out.emit(f"_Py_CODEUNIT *this_instr = next_instr - {mac.cache_offset+1};")
         out.static_assert_family_size(mac.name, mac.family, mac.cache_offset)
         try:
             next_instr_is_set = write_components(
@@ -375,8 +384,6 @@ def write_macro_instr(mac: MacroInstruction, out: Formatter) -> None:
         except AssertionError as err:
             raise AssertionError(f"Error writing macro {mac.name}") from err
         if not parts[-1].instr.always_exits:
-            if not next_instr_is_set and mac.cache_offset:
-                out.emit(f"next_instr += {mac.cache_offset};")
             if parts[-1].instr.check_eval_breaker:
                 out.emit("CHECK_EVAL_BREAKER();")
             out.emit("DISPATCH();")
@@ -450,8 +457,6 @@ def write_components(
 
         if mgr.instr.name == "_SAVE_RETURN_OFFSET":
             next_instr_is_set = True
-            if cache_offset:
-                out.emit(f"next_instr += {cache_offset};")
             if tier == TIER_ONE:
                 assert_no_pokes(managers)