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| author | Björn Gustavsson <[email protected]> | 2017-09-13 12:56:06 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2017-09-14 10:23:17 +0200 |
| commit | 4bf642e54bca72d77b64af4409a13188dd5c7378 (patch) | |
| tree | 5ef6a1cd9b7b6ec4c0a6fcd9cb6c501625bbbd50 | |
| parent | ddaed7774eb0a3bbaf6ee40153d2b082181a1223 (diff) | |
| download | otp-4bf642e54bca72d77b64af4409a13188dd5c7378.tar.gz otp-4bf642e54bca72d77b64af4409a13188dd5c7378.tar.bz2 otp-4bf642e54bca72d77b64af4409a13188dd5c7378.zip | |
Correct disassembly of select instructions
Make sure to use the 'unpacked[-1]' when accessing the unpacked
arguments.
| -rw-r--r-- | erts/emulator/beam/beam_debug.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/erts/emulator/beam/beam_debug.c b/erts/emulator/beam/beam_debug.c index afde45ba71..7017656476 100644 --- a/erts/emulator/beam/beam_debug.c +++ b/erts/emulator/beam/beam_debug.c @@ -629,13 +629,20 @@ print_op(fmtfn_t to, void *to_arg, int op, int size, BeamInstr* addr) unpacked = ap; ap = addr + size; + + /* + * In the code below, never use ap[-1], ap[-2], ... + * (will not work if the arguments have been packed). + * + * Instead use unpacked[-1], unpacked[-2], ... + */ switch (op) { case op_i_select_val_lins_xfI: case op_i_select_val_lins_yfI: case op_i_select_val_bins_xfI: case op_i_select_val_bins_yfI: { - int n = ap[-1]; + int n = unpacked[-1]; int ix = n; Sint32* jump_tab = (Sint32 *)(ap + n); @@ -656,7 +663,7 @@ print_op(fmtfn_t to, void *to_arg, int op, int size, BeamInstr* addr) case op_i_select_tuple_arity_xfI: case op_i_select_tuple_arity_yfI: { - int n = ap[-1]; + int n = unpacked[-1]; int ix = n - 1; /* without sentinel */ Sint32* jump_tab = (Sint32 *)(ap + n); @@ -698,7 +705,7 @@ print_op(fmtfn_t to, void *to_arg, int op, int size, BeamInstr* addr) case op_i_jump_on_val_xfIW: case op_i_jump_on_val_yfIW: { - int n = ap[-2]; + int n = unpacked[-2]; Sint32* jump_tab = (Sint32 *) ap; size += (n+1) / 2; @@ -712,7 +719,7 @@ print_op(fmtfn_t to, void *to_arg, int op, int size, BeamInstr* addr) case op_i_jump_on_val_zero_xfI: case op_i_jump_on_val_zero_yfI: { - int n = ap[-1]; + int n = unpacked[-1]; Sint32* jump_tab = (Sint32 *) ap; size += (n+1) / 2; |