https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84864
Bug ID: 84864
Summary: Issues with large line numbers >= 2^31
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Keywords: deferred, diagnostic
Severity: normal
Priority: P3
Component: preprocessor
Assignee: unassigned at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Target Milestone: ---
PR 84852 describes an ICE on this source code:
$ cat test.c
#line 7777777777
int foo (void) { return strlen(""); }
On fixing the ICE, the #line directive leads to negative line numbers, with the
diagnostic reported here:
test.c:-812156815:25:
The 7777777777 is truncated to unsigned 32 bits (linenum_type), from
0x1cf977871 to 0xcf977871 == 3482810481.
In some places we use linenum_type (unsigned int); in others we use int,
leading to the printing of -812156815 for the line number.
We already warn for too-large line numbers with -pedantic:
test.c:1:7: warning: line number out of range
#line 7777777777
^~~~~~~~~~
There seem to be at least two issues here:
* silent truncation of #line
* use of negative numbers for such cases
I experimented with using linenum_type throughout for the fix for PR 84852, but
it was more invasive that I'd have liked in stage 4, so filing this to track
addressing this when stage 1 opens.
