[gdb/symtab] Fix function range handling in psymtabs

[gdb/symtab] Fix function range handling in psymtabs

Consider the test-case from this patch.

We run into:
...
(gdb) PASS: gdb.dwarf2/dw2-ranges-psym-warning.exp: continue
bt^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
warning: (Internal error: pc 0x4004b6 in read in psymtab, but not in symtab.)^M
^M
  read in psymtab, but not in symtab.)^M
^M
)^M
(gdb) FAIL: gdb.dwarf2/dw2-ranges-psym-warning.exp: bt
...

This happens as follows.

The function foo:
...
 <1><31>: Abbrev Number: 4 (DW_TAG_subprogram)
    <33>   DW_AT_name        : foo
    <37>   DW_AT_ranges      : 0x0
...
has these ranges:
...
    00000000 00000000004004c1 00000000004004d2
    00000000 00000000004004ae 00000000004004af
    00000000 <End of list>
...
which have a hole at at [0x4004af,0x4004c1).

However, the address map of the partial symtabs incorrectly maps addresses
in the hole (such as 0x4004b6 in the backtrace) to the foo CU.

The address map of the full symbol table of the foo CU however does not
contain the addresses in the hole, which is what the warning / internal error
complains about.

Fix this by making sure that ranges of functions are read correctly.

The patch adds a bit to struct partial_die_info, in this hole (shown for
x86_64-linux):
...
/*   11: 7   |     4 */    unsigned int canonical_name : 1;
/* XXX  4-byte hole  */
/*   16      |     8 */    const char *raw_name;
...
So there's no increase in size for 64-bit, but AFAIU there will be an increase
for 32-bit.

Tested on x86_64-linux.

gdb/ChangeLog:

2021-08-10  Tom de Vries  <tdevries@suse.de>

	PR symtab/28200
	* dwarf2/read.c (struct partial_die_info): Add has_range_info and
	range_offset field.
	(add_partial_subprogram): Handle pdi->has_range_info.
	(partial_die_info::read): Set pdi->has_range_info.

gdb/testsuite/ChangeLog:

2021-08-10  Tom de Vries  <tdevries@suse.de>

	PR symtab/28200
	* gdb.dwarf2/dw2-ranges-psym-warning-main.c: New test.
	* gdb.dwarf2/dw2-ranges-psym-warning.c: New test.
	* gdb.dwarf2/dw2-ranges-psym-warning.exp: New file.