When printing source lines with calls to print_source_lines we need to
pass a start line number and an end line number. The end line number
is calculated by calling get_lines_to_list and adding this value to
the start line number. For example this code from list_command:
print_source_lines (cursal.symtab, first,
first + get_lines_to_list (), 0);
The problem is that get_lines_to_list returns a value based on the
GDB setting `set listsize LISTSIZE`. By default LISTSIZE is 10,
however, its also possible to set LISTSIZE to unlimited, in which
case get_lines_to_list will return INT_MAX.
As the parameter signature for print_source_lines is:
void print_source_lines (struct symtab *, int, int,
print_source_lines_flags);
and `first` in the above code is an `int`, then when LISTSIZE is
`unlimited` the above code will result in signed integer overflow,
which is undefined.
The solution in this patch is a new class source_lines_range that can
be constructed from a single line number and a direction (forward or
backward). The range is then constructed from the line number and the
value of get_lines_to_list.
gdb/ChangeLog:
* cli/cli-cmds.c (list_command): Pass a source_lines_range to
print_source_lines.
* source.c (print_source_lines_base): Update line number check.
(print_source_lines): New function.
(source_lines_range::source_lines_range): New function.
* source.h (class source_lines_range): New class.
(print_source_lines): New declaration.
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