diff options
author | Michael W. Hudson <mwh@python.net> | 2002-08-30 13:09:51 (GMT) |
---|---|---|
committer | Michael W. Hudson <mwh@python.net> | 2002-08-30 13:09:51 (GMT) |
commit | 53d58bb369fbbc1ae93ca423f30b3beb2d83a9a1 (patch) | |
tree | d2cfada7ddfa673a343155bfbad7de1166ea3790 /Python/ceval.c | |
parent | b05e056e9f17f68daf106e1b018d1bbab2943148 (diff) | |
download | cpython-53d58bb369fbbc1ae93ca423f30b3beb2d83a9a1.zip cpython-53d58bb369fbbc1ae93ca423f30b3beb2d83a9a1.tar.gz cpython-53d58bb369fbbc1ae93ca423f30b3beb2d83a9a1.tar.bz2 |
Further SET_LINENO reomval fixes. See comments in patch #587933.
Use a slightly different strategy to determine when not to call the line
trace function. This removes the need for the RETURN_NONE opcode, so
that's gone again. Update docs and comments to match.
Thanks to Neal and Armin!
Also add a test suite. This should have come with the original patch...
Diffstat (limited to 'Python/ceval.c')
-rw-r--r-- | Python/ceval.c | 54 |
1 files changed, 20 insertions, 34 deletions
diff --git a/Python/ceval.c b/Python/ceval.c index d4be04e..8bd945e 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -1515,12 +1515,6 @@ eval_frame(PyFrameObject *f) why = WHY_RETURN; break; - case RETURN_NONE: - retval = Py_None; - Py_INCREF(retval); - why = WHY_RETURN; - break; - case YIELD_VALUE: retval = POP(); f->f_stacktop = stack_pointer; @@ -2880,9 +2874,8 @@ maybe_call_line_trace(int opcode, Py_tracefunc func, PyObject *obj, This is all fairly simple. Digging the information out of co_lnotab takes some work, but is conceptually clear. - Somewhat harder to explain is why we don't call the line - trace function when executing a POP_TOP or RETURN_NONE - opcodes. An example probably serves best. + Somewhat harder to explain is why we don't *always* call the + line trace function when the above test fails. Consider this code: @@ -2907,7 +2900,8 @@ maybe_call_line_trace(int opcode, Py_tracefunc func, PyObject *obj, 5 16 LOAD_CONST 2 (2) 19 PRINT_ITEM 20 PRINT_NEWLINE - >> 21 RETURN_NONE + >> 21 LOAD_CONST 0 (None) + 24 RETURN_VALUE If a is false, execution will jump to instruction at offset 15 and the co_lnotab will claim that execution has moved to @@ -2915,56 +2909,48 @@ maybe_call_line_trace(int opcode, Py_tracefunc func, PyObject *obj, associate the POP_TOP with line 4, but that doesn't make sense in all cases (I think). - On the other hand, if a is true, execution will jump from - instruction offset 12 to offset 21. Then the co_lnotab would - imply that execution has moved to line 5, which is again - misleading. - - This is why it is important that RETURN_NONE is *only* used - for the "falling off the end of the function" form of - returning None -- using it for code like - - 1: def f(): - 2: return + What we do is only call the line trace function if the co_lnotab + indicates we have jumped to the *start* of a line, i.e. if the + current instruction offset matches the offset given for the + start of a line by the co_lnotab. - would, once again, lead to misleading tracing behaviour. - - It is also worth mentioning that getting tracing behaviour - right is the *entire* motivation for adding the RETURN_NONE - opcode. + This also takes care of the situation where a is true. + Execution will jump from instruction offset 12 to offset 21. + Then the co_lnotab would imply that execution has moved to line + 5, which is again misleading. */ - if (opcode != POP_TOP && opcode != RETURN_NONE && - (frame->f_lasti < *instr_lb || frame->f_lasti > *instr_ub)) { + if ((frame->f_lasti < *instr_lb || frame->f_lasti >= *instr_ub)) { PyCodeObject* co = frame->f_code; int size, addr; unsigned char* p; - call_trace(func, obj, frame, PyTrace_LINE, Py_None); + size = PyString_GET_SIZE(co->co_lnotab) / 2; + p = (unsigned char*)PyString_AS_STRING(co->co_lnotab); - size = PyString_Size(co->co_lnotab) / 2; - p = (unsigned char*)PyString_AsString(co->co_lnotab); + addr = 0; /* possible optimization: if f->f_lasti == instr_ub (likely to be a common case) then we already know instr_lb -- if we stored the matching value of p somwhere we could skip the first while loop. */ - addr = 0; - /* see comments in compile.c for the description of co_lnotab. A point to remember: increments to p should come in pairs -- although we don't care about the line increments here, treating them as byte increments gets confusing, to say the least. */ - while (size >= 0) { + while (size > 0) { if (addr + *p > frame->f_lasti) break; addr += *p++; p++; --size; } + if (addr == frame->f_lasti) + call_trace(func, obj, frame, + PyTrace_LINE, Py_None); *instr_lb = addr; if (size > 0) { while (--size >= 0) { |