From b29fae0c564bae271f3659563a2a61230dab5def Mon Sep 17 00:00:00 2001 From: Damien George Date: Mon, 2 Sep 2019 13:30:16 +1000 Subject: [PATCH] py/bc: Fix size calculation of UNWIND_JUMP opcode in mp_opcode_format. Prior to this patch mp_opcode_format would calculate the incorrect size of the MP_BC_UNWIND_JUMP opcode, missing the additional byte. But, because opcodes below 0x10 are unused and treated as bytes in the .mpy load/save and freezing code, this bug did not show any symptoms, since nested unwind jumps would rarely (if ever) reach a depth of 16 (so the extra byte of this opcode would be between 0x01 and 0x0f and be correctly loaded/saved/frozen simply as an undefined opcode). This patch fixes this bug by correctly accounting for the additional byte. . --- py/bc.c | 6 ++- tests/basics/try_except_break.py | 73 ++++++++++++++++++++++++++++ tests/basics/try_except_break.py.exp | 3 ++ tools/mpy-tool.py | 4 +- 4 files changed, 83 insertions(+), 3 deletions(-) create mode 100644 tests/basics/try_except_break.py create mode 100644 tests/basics/try_except_break.py.exp diff --git a/py/bc.c b/py/bc.c index 7d0b13bd74..5625da8cf3 100644 --- a/py/bc.c +++ b/py/bc.c @@ -292,7 +292,8 @@ continue2:; #if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE // The following table encodes the number of bytes that a specific opcode -// takes up. There are 3 special opcodes that always have an extra byte: +// takes up. There are 4 special opcodes that always have an extra byte: +// MP_BC_UNWIND_JUMP // MP_BC_MAKE_CLOSURE // MP_BC_MAKE_CLOSURE_DEFARGS // MP_BC_RAISE_VARARGS @@ -402,7 +403,8 @@ uint mp_opcode_format(const byte *ip, size_t *opcode_size, bool count_var_uint) ip += 3; } else { int extra_byte = ( - *ip == MP_BC_RAISE_VARARGS + *ip == MP_BC_UNWIND_JUMP + || *ip == MP_BC_RAISE_VARARGS || *ip == MP_BC_MAKE_CLOSURE || *ip == MP_BC_MAKE_CLOSURE_DEFARGS ); diff --git a/tests/basics/try_except_break.py b/tests/basics/try_except_break.py new file mode 100644 index 0000000000..a7683f2185 --- /dev/null +++ b/tests/basics/try_except_break.py @@ -0,0 +1,73 @@ +# test deep unwind via break from nested try-except (22 of them) +while True: + print(1) + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + try: + print(2) + break + print(3) + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass + except: + pass +print(4) diff --git a/tests/basics/try_except_break.py.exp b/tests/basics/try_except_break.py.exp new file mode 100644 index 0000000000..e8a01cd985 --- /dev/null +++ b/tests/basics/try_except_break.py.exp @@ -0,0 +1,3 @@ +1 +2 +4 diff --git a/tools/mpy-tool.py b/tools/mpy-tool.py index 3d2a8fb7c6..e5c8f09597 100755 --- a/tools/mpy-tool.py +++ b/tools/mpy-tool.py @@ -109,6 +109,7 @@ MP_OPCODE_VAR_UINT = 2 MP_OPCODE_OFFSET = 3 # extra bytes: +MP_BC_UNWIND_JUMP = 0x46 MP_BC_MAKE_CLOSURE = 0x62 MP_BC_MAKE_CLOSURE_DEFARGS = 0x63 MP_BC_RAISE_VARARGS = 0x5c @@ -215,7 +216,8 @@ def mp_opcode_format(bytecode, ip, count_var_uint, opcode_format=make_opcode_for ip += 3 else: extra_byte = ( - opcode == MP_BC_RAISE_VARARGS + opcode == MP_BC_UNWIND_JUMP + or opcode == MP_BC_RAISE_VARARGS or opcode == MP_BC_MAKE_CLOSURE or opcode == MP_BC_MAKE_CLOSURE_DEFARGS )