co_lnotab supports negative line number delta
Issue #26107: The format of the co_lnotab attribute of code objects changes to
support negative line number delta.
Changes:
* assemble_lnotab(): if line number delta is less than -128 or greater than
127, emit multiple (offset_delta, lineno_delta) in co_lnotab
* update functions decoding co_lnotab to use signed 8-bit integers
- dis.findlinestarts()
- PyCode_Addr2Line()
- _PyCode_CheckLineNumber()
- frame_setlineno()
* update lnotab_notes.txt
* increase importlib MAGIC_NUMBER to 3361
* document the change in What's New in Python 3.6
* cleanup also PyCode_Optimize() to use better variable names
diff --git a/Objects/codeobject.c b/Objects/codeobject.c
index b0e3446..0f03dfe 100644
--- a/Objects/codeobject.c
+++ b/Objects/codeobject.c
@@ -557,7 +557,8 @@
addr += *p++;
if (addr > addrq)
break;
- line += *p++;
+ line += (signed char)*p;
+ p++;
}
return line;
}
@@ -592,17 +593,19 @@
if (addr + *p > lasti)
break;
addr += *p++;
- if (*p)
+ if ((signed char)*p)
bounds->ap_lower = addr;
- line += *p++;
+ line += (signed char)*p;
+ p++;
--size;
}
if (size > 0) {
while (--size >= 0) {
addr += *p++;
- if (*p++)
+ if ((signed char)*p)
break;
+ p++;
}
bounds->ap_upper = addr;
}