diff options
| -rw-r--r-- | erts/emulator/beam/beam_emu.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 3c323634b7..a7d7e851cf 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -5687,6 +5687,25 @@ expand_error_value(Process* c_p, Uint freason, Eterm Value) { * that c_p->ftrace will point to a cons cell which holds the given args * and the saved data (encoded as a bignum). * + * There is an issue with line number information. Line number + * information is associated with the address *before* an operation + * that may fail or be stored stored on the stack. But continuation + * pointers point after its call instruction, not before. To avoid + * finding the wrong line number, we'll need to adjust them so that + * they point at the beginning of the call instruction or inside the + * call instruction. Since its impractical to point at the beginning, + * we'll do the simplest thing and decrement the continuation pointers + * by one. + * + * Here is an example of what can go wrong. Without the adjustment + * of continuation pointers, the call at line 42 below would seem to + * be at line 43: + * + * line 42 + * call ... + * line 43 + * gc_bif ... + * * (It would be much better to put the arglist - when it exists - in the * error value instead of in the actual trace; e.g. '{badarg, Args}' * instead of using 'badarg' with Args in the trace. The arglist may @@ -5753,7 +5772,7 @@ save_stacktrace(Process* c_p, BeamInstr* pc, Eterm* reg, BifFunction bf, } /* Save second stack entry if CP is valid and different from pc */ if (depth > 0 && c_p->cp != 0 && c_p->cp != pc) { - s->trace[s->depth++] = c_p->cp; + s->trace[s->depth++] = c_p->cp - 1; depth--; } s->pc = NULL; @@ -5773,13 +5792,13 @@ save_stacktrace(Process* c_p, BeamInstr* pc, Eterm* reg, BifFunction bf, /* Save first stack entry */ ASSERT(c_p->cp); if (depth > 0) { - s->trace[s->depth++] = c_p->cp; + s->trace[s->depth++] = c_p->cp - 1; depth--; } s->pc = NULL; /* Ignore pc */ } else { if (depth > 0 && c_p->cp != 0 && c_p->cp != pc) { - s->trace[s->depth++] = c_p->cp; + s->trace[s->depth++] = c_p->cp - 1; depth--; } s->pc = pc; @@ -5835,7 +5854,7 @@ save_stacktrace(Process* c_p, BeamInstr* pc, Eterm* reg, BifFunction bf, if (cp != prev) { /* Record non-duplicates only */ prev = cp; - s->trace[s->depth++] = cp; + s->trace[s->depth++] = cp - 1; depth--; } ptr++; |