Category
GDB.
Synopsis
gdb cannot find line numbers of certain weak symbols during backtrace
Confidential
No
Severity
Serious
Priority
Medium
Submitter-Id
net.
Release
% gdb
GNU gdb (GDB) 7.7
Environment
* the operating system verson (output of uname -a)
Linux lc-sj1-4507 2.6.18-308.11.1.el5 #1 SMP Fri Jun 15 15:41:53 EDT 2012
x86_64 x86_64 x86_64 GNU/Linux
* the compiler version (for GCC, the output from gcc -v)
g++ (GCC) 4.7.2
* how GDB was configured (the This GDB was configured as line from
GDB's startup text)
This GDB was configured as x86_64-unknown-linux-gnu.
How-To-Repeat
Unfortunately I don't have a simple testcase to repeat. I will work
on it in the background, to see if I can reproduce it.
Here are the compile flags I used:
g++ -O0 -ggdb -pthread -m32 -fPIC -Wall -Wno-unknown-pragmas -Wno-error
-Wno-deprecated -Wno-unused-variable -Wno-overloaded-virtual -Wno-enum-compare
-Wno-write-strings -fpermissive -Wno-div-by-zero ...
I have also tried -fno-inline and it made no difference.
Description
The problem is that gdb does not print line numbers for only couple items in
the stack frame even though everything was built using the -ggdb switch. Here
is a stack trace, notice that #10 and #11 do not have the file and line numbers
associated with them, everything else does.
(gdb) where
#0 0xe410 in __kernel_vsyscall ()
#1 0x002d5df0 in raise () from /lib/libc.so.6
#2 0x002d7701 in abort () from /lib/libc.so.6
#3 0x002cf26b in __assert_fail () from /lib/libc.so.6
#4 0x082e0d0f in
FLEX_HASH_TABLE::search_bankTD3::uft_search_stage_params::check_base_entry_width
(this=0x8a88f7c BM_BaseTest::Iss+65564,
base_entry_width=4, req_in=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/include/ip/flex_hash_table/src/search_bank.h:1119
#5 0x082dd698 in
FLEX_HASH_TABLE::search_bankTD3::uft_search_stage_params::table_search
(this=0x8a88f7c BM_BaseTest::Iss+65564, req_in=...,
rst_out=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/include/ip/flex_hash_table/src/search_bank.h:717
#6 0x082da27d in
FLEX_HASH_TABLE::search_bankTD3::uft_search_stage_params::process_bank_req
(this=0x8a88f7c BM_BaseTest::Iss+65564, req_in=...,
rst_out=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/include/ip/flex_hash_table/src/search_bank.h:324
#7 0x082d952d in
FLEX_HASH_TABLE::search_stageTD3::uft_search_stage_params::process_req
(this=0x8a78f60 BM_BaseTest::Iss, req=..., rst=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/include/ip/flex_hash_table/src/search_stage.h:307
#8 0x0833f085 in TD3::fb_uft_ss::process_req (
this=0x8a78f60 BM_BaseTest::Iss, req=..., rst=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/ip/flex_hash_table/src/trident3/fb_uft_ss.cc:32
#9 0x082e34b7 in FLEX_HASH_TABLE::search_stages::process_search_req (
this=0x8c16918, req=..., rst=...)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/include/ip/flex_hash_table/src/search_stages.h:176
#10 0x0833554c in
FLEX_HASH_TABLE::flex_hash_tableTD3::fb_l3_search::l3_ht_params::process_table_req(FLEX_HASH_TABLE::REQ_BUS,
FLEX_HASH_TABLE::RST_BUS) ()
#11 0x08332de3 in
FLEX_HASH_TABLE::flex_hash_tableTD3::fb_l3_search::l3_ht_params::hash_table_lookup(SchanMsg,
FLEX_HASH_TABLE::flex_hash_table_width_t) ()
#12 0x0833127f in TD3::fb_l3_search::table_lookup (
this=0x8ab9000 BM_BaseTest::l3_search, smsg=..., table_type=3284)
at
/projects/ntsw-arch3/AV/users/runipg/rg_arch2/arch/ip/flex_hash_table/src/trident3/fb_l3_search.cc:310
I looked through the object files using nm and the executable using
readelf. These symbols are listed as weak symbols.
% readelf -t --wide --symbols test_flex_ht.linux | grep l3_search | grep
hash_table_lookup
43328: 08332ca8 810 FUNCWEAK DEFAULT 12
_ZN15FLEX_HASH_TABLE15flex_hash_tableIN3TD312fb_l3_search12l3_ht_paramsEE17hash_table_lookupER8SchanMsgNS_23flex_hash_table_width_tE
Just FYI, the object itself lives in a static global store.
Thanks for looking into it!
Runip
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