Re: [PATCH] Add "set debug minsyms" command

Simon Marchi
2018-12-21T23:07:57Z

On 2018-12-21 4:59 p.m., John Baldwin wrote:
>> diff --git a/gdb/auto-load.c b/gdb/auto-load.c
>> index 33d282afe83..e35fd29426b 100644
>> --- a/gdb/auto-load.c
>> +++ b/gdb/auto-load.c
>> @@ -1175,6 +1175,8 @@ load_auto_scripts_for_objfile (struct objfile *objfile)
>> static void
>> auto_load_new_objfile (struct objfile *objfile)
>> {
>> + std::vector <int> c;
>> + c.clear();
>> if (!objfile)
>> {
>> /* OBJFILE is NULL when loading a new "main" symbol-file. */
>
> This seems spurious (also not in ChangeLog)?
>
>> diff --git a/gdb/elfread.c b/gdb/elfread.c
>> index 71e6fcca6ec..359089b166c 100644
>> --- a/gdb/elfread.c
>> +++ b/gdb/elfread.c
>> @@ -249,6 +249,8 @@ elf_symtab_read (minimal_symbol_reader &reader,
>> continue;
>> }
>>
>> + printf(" --- %s\n", sym->name);
>> +
>> /* Skip "special" symbols, e.g. ARM mapping symbols. These are
>> symbols which do not correspond to objects in the symbol table,
>> but have some other target-specific meaning. */
>
> Likewise.

Woops, I meant to remove those changes, looks like I amended instead by mistake.

>> diff --git a/gdb/minsyms.c b/gdb/minsyms.c
>> index 0f854422e0f..98ce969eed0 100644
>> --- a/gdb/minsyms.c
>> +++ b/gdb/minsyms.c
>> @@ -1112,6 +1143,11 @@ minimal_symbol_reader::record_full (const char *name, int name_len,
>> if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
>> return (NULL);
>>
>> + if (debug_minsyms)
>> + printf_unfiltered
>> + ("minsym: recording minsym type: %-21s addr: 0x%016llx section: %-5d name: %s\n",
>> + mst_str (ms_type), (long long) address, section, name);
>
> Maybe plongest() instead of %llx? Or does plongest not do the leading 0 fill
> you want?
I don't really mind about the leading 0s, it's just that having fixed width, right aligned
and padded with spaces would give something like "0x 1234". But I ended up using
hex_string.

Here's v2:

From 388db2a2b0299ac769943f7840c3cd4e01a216ac Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@ericsson.com>
Date: Thu, 20 Dec 2018 11:43:52 -0500
Subject: [PATCH] Add debug output for recorded minsyms

While discussing this issue:

https://sourceware.org/ml/gdb-patches/2018-12/threads.html#00082

I added a printf to be able to quickly see all minimal symbols recorded
by GDB. I thought it would be useful to have it built-in, for the
future.

Recording minsym: mst_data 0x400780 15 _IO_stdin_used
Recording minsym: mst_text 0x400700 13 __libc_csu_init
Recording minsym: mst_bss 0x601058 25 _end

New since v1:

- Remove unrelated changes
- Don't print field names
- Use hex_string to print addresses
- Don't add a new "set debug" knob, use "set debug symtab-create" instead.
Output this when the value is >= 2, since there can be quite a lot of
symbols.

gdb/ChangeLog:

* minsyms.c (mst_str): New.
(minimal_symbol_reader::record_full): Add debug output.
---
gdb/minsyms.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 0f854422e0f..71d630374ac 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -1080,6 +1080,33 @@ minimal_symbol_reader::record (const char *name, CORE_ADDR address,
record_with_info (name, address, ms_type, section);
}

+/* Convert an enumerator of type minimal_symbol_type to its string
+ representation. */
+
+static const char *
+mst_str (minimal_symbol_type t)
+{
+#define MST_TO_STR(x) case x: return #x;
+ switch (t)
+ {
+ MST_TO_STR (mst_unknown);
+ MST_TO_STR (mst_text);
+ MST_TO_STR (mst_text_gnu_ifunc);
+ MST_TO_STR (mst_slot_got_plt);
+ MST_TO_STR (mst_data);
+ MST_TO_STR (mst_bss);
+ MST_TO_STR (mst_abs);
+ MST_TO_STR (mst_solib_trampoline);
+ MST_TO_STR (mst_file_text);
+ MST_TO_STR (mst_file_data);
+ MST_TO_STR (mst_file_bss);
+
+ default:
+ return "mst_???";
+ }
+#undef MST_TO_STR
+}
+
/* See minsyms.h. */

struct minimal_symbol *
@@ -1112,6 +1139,10 @@ minimal_symbol_reader::record_full (const char *name, int name_len,
if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
return (NULL);

+ if (symtab_create_debug >= 2)
+ printf_unfiltered ("Recording minsym: %-21s %18s %4d %s\n",
+ mst_str (ms_type), hex_string (address), section, name);
+
if (m_msym_bunch_index == BUNCH_SIZE)
{
newobj = XCNEW (struct msym_bunch);
--
2.20.1