Re: [PATCH][gdb] Fix s390x -m31 build

Tom de Vries
2019-06-22T09:01:51Z

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On 21-06-19 19:07, Tom de Vries wrote:
> On 21-06-19 18:05, Tom Tromey wrote:
>>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
>>
>> Tom> Fix this by changing the length modifier from 'z' to the ptrdiff_t length
>> Tom> modifier 't', and change the conversion specifier from 'u' to the more
>> Tom> appropriate 'd'.
>>
>> gdb probably shouldn't be using 'z' anyway. IIRC it causes problems on
>> Windows.
>>
>> How portable is %td? I do not know. Maybe check the gnulib manual and
>> see what they have to say about it? Anyway, this is my main concern
>> with this patch.
>>
>
> I found here ( https://www.gnu.org/software/gnulib/manual/gnulib.html ):
> ...
> Portability problems fixed by Gnulib module fprintf-posix:
>
> This function does not support size specifiers as in C99 (hh, ll, j,
> t, z) on some platforms: AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1,
> Solaris 9, Cygwin 1.5.24, mingw, MSVC 14, BeOS.
> ...
>
>> The standard gdb approach here is to use plongest / pulongest in
>> conjunction with %s. That avoids any problems.
>
> I'll update the patch to use that method, thanks for pointing that out.

Committed as attached.

Thanks,
- Tom

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[gdb] Fix s390x -m31 build

When building gdb on s390x with -m31, we run into this Wformat
warning (which Werror turns into an error):
...
gdb/dwarf2read.c: In function \
'void create_addrmap_from_aranges(dwarf2_per_objfile*, \
dwarf2_section_info*)':
gdb/dwarf2read.c:3277:22: error: format '%zu' expects argument of type \
'size_t', but argument 3 has type 'int' [-Werror=format=]
warning (_("Section .debug_aranges in %s entry at offset %zu "
...

The Wformat warning is triggered in this statement:
...
warning (_("Section .debug_aranges in %s entry at offset %zu "
"length %s exceeds section length %s, "
"ignoring .debug_aranges."),
objfile_name (objfile), entry_addr - section->buffer,
plongest (bytes_read + entry_length),
pulongest (section->size));
...
where 'entry_addr - section->buffer' is of type ptrdiff_t and '%zu' prints an
unsigned with the same size as size_t/ssize_t.

On s390x with -m31, we have:
- size_t : unsigned long int (32-bit)
- ptrdiff_t: int (32-bit)

Wformat warns against this because even though long int and int have the same
size, the types are not compatible.

[ The Wformat warning is to similar to what we would get for x86_64 -m32
(where long and int are also the same size) and:
...
int i;
printf ("%ld", i);
... ]

Fix this by using '%s' and plongest instead of '%zu' to print ptrdiff_t.

Build and reg-tested on x86_64.

gdb/ChangeLog:

2019-06-20 Tom de Vries <tdevries@suse.de>

* dwarf2read.c (create_addrmap_from_aranges)
(read_debug_names_from_section): Print ptrdiff_t using '%s' and plongest
instead of '%zu'.

---
gdb/dwarf2read.c | 42 ++++++++++++++++++++++++------------------
1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index fccbd05e2d..85f2b1dfc4 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -3229,10 +3229,11 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
const uint8_t offset_size = dwarf5_is_dwarf64 ? 8 : 4;
if (addr + entry_length > section->buffer + section->size)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"length %s exceeds section length %s, "
"ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer,
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer),
plongest (bytes_read + entry_length),
pulongest (section->size));
return;
@@ -3243,10 +3244,10 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
addr += 2;
if (version != 2)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"has unsupported version %d, ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer,
- version);
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer), version);
return;
}

@@ -3257,10 +3258,11 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
= debug_info_offset_to_per_cu.find (sect_offset (debug_info_offset));
if (per_cu_it == debug_info_offset_to_per_cu.cend ())
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"debug_info_offset %s does not exists, "
"ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer,
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer),
pulongest (debug_info_offset));
return;
}
@@ -3269,20 +3271,21 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
const uint8_t address_size = *addr++;
if (address_size < 1 || address_size > 8)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"address_size %u is invalid, ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer,
- address_size);
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer), address_size);
return;
}

const uint8_t segment_selector_size = *addr++;
if (segment_selector_size != 0)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"segment_selector_size %u is not supported, "
"ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer,
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer),
segment_selector_size);
return;
}
@@ -3295,9 +3298,10 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
padding > 0; padding--)
if (*addr++ != 0)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"padding is not zero, ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer);
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer));
return;
}

@@ -3305,10 +3309,11 @@ create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
{
if (addr + 2 * address_size > entry_end)
{
- warning (_("Section .debug_aranges in %s entry at offset %zu "
+ warning (_("Section .debug_aranges in %s entry at offset %s "
"address list is not properly terminated, "
"ignoring .debug_aranges."),
- objfile_name (objfile), entry_addr - section->buffer);
+ objfile_name (objfile),
+ plongest (entry_addr - section->buffer));
return;
}
ULONGEST start = extract_unsigned_integer (addr, address_size,
@@ -5517,8 +5522,9 @@ read_debug_names_from_section (struct objfile *objfile,
if (addr != abbrev_table_start + abbrev_table_size)
{
warning (_("Section .debug_names in %s has abbreviation_table "
- "of size %zu vs. written as %u, ignoring .debug_names."),
- filename, addr - abbrev_table_start, abbrev_table_size);
+ "of size %s vs. written as %u, ignoring .debug_names."),
+ filename, plongest (addr - abbrev_table_start),
+ abbrev_table_size);
return false;
}
map.entry_pool = addr;