From 55824d01f866d1fa0f21996d897fba0e07d09ac8 Mon Sep 17 00:00:00 2001 From: Mark Shannon Date: Thu, 11 Jan 2024 18:20:42 +0000 Subject: GH-113853: Guarantee forward progress in executors (GH-113854) --- Python/bytecodes.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'Python/bytecodes.c') diff --git a/Python/bytecodes.c b/Python/bytecodes.c index f53ddae8df9..2011d963e36 100644 --- a/Python/bytecodes.c +++ b/Python/bytecodes.c @@ -2325,12 +2325,18 @@ dummy_func( // Double-check that the opcode isn't instrumented or something: if (ucounter > threshold && this_instr->op.code == JUMP_BACKWARD) { OPT_STAT_INC(attempts); - int optimized = _PyOptimizer_BackEdge(frame, this_instr, next_instr, stack_pointer); + _Py_CODEUNIT *start = this_instr; + /* Back up over EXTENDED_ARGs so optimizer sees the whole instruction */ + while (oparg > 255) { + oparg >>= 8; + start--; + } + int optimized = _PyOptimizer_Optimize(frame, start, stack_pointer); ERROR_IF(optimized < 0, error); if (optimized) { // Rewind and enter the executor: - assert(this_instr->op.code == ENTER_EXECUTOR); - next_instr = this_instr; + assert(start->op.code == ENTER_EXECUTOR); + next_instr = start; this_instr[1].cache &= ((1 << OPTIMIZER_BITS_IN_COUNTER) - 1); } else { @@ -2370,10 +2376,12 @@ dummy_func( GOTO_TIER_TWO(); } else { - code->co_executors->executors[oparg & 255] = NULL; + /* ENTER_EXECUTOR will be the first code unit of the instruction */ + assert(oparg < 256); + code->co_executors->executors[oparg] = NULL; opcode = this_instr->op.code = executor->vm_data.opcode; this_instr->op.arg = executor->vm_data.oparg; - oparg = (oparg & (~255)) | executor->vm_data.oparg; + oparg = executor->vm_data.oparg; Py_DECREF(executor); next_instr = this_instr; DISPATCH_GOTO(); -- cgit v1.2.3