I have the following versions of Cygwin, yasm, gcc, and gdb:
CYGWIN_NT-5.1 Thorondor 1.7.7(0.230/5/3) 2010-08-31 09:58 i686 Cygwin
yasm 1.1.0.2352
gcc (GCC) 3.4.4 (cygming special, gdc 0.12, using dmd 0.125)
GNU gdb 6.8.0.20080328-cvs (cygwin-special)
I've compiled vp8 using the following commands:
$ ./configure --enable-debug
$ make
However when I try to debug using GDB, I get the following error:
$ gdb simple_decoder.exe
GNU gdb 6.8.0.20080328-cvs (cygwin-special)
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/
gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show
copying"
and "show warranty" for details.
This GDB was configured as "i686-pc-cygwin"...
Dwarf Error: bad offset (0x4c4000) in compilation unit header (offset
0x0 + 6) [in module /cygdrive/
c/work/vp8/csim/build/simple_decoder.exe]
(gdb) q
Can someone help me out with this?
Thanks,
Arjun
Your compiler and binutils are too old. This was solved circa 2000, the fault comes from the linker (see http://gcc.gnu.org/ml/gcc-bugs/2000-06/msg00768.html)
Related
Problem
I'm trying to debug this Rust program using rust-gdb, but I can't seem to get GDB to work properly:
/home/a/tmp/foo(HEAD)
09/19/2021 09:57:23.114 AM> rust-gdb -q target/debug/foo
Reading symbols from target/debug/foo...
(gdb) b hello
Breakpoint 1 at 0x7a44: file src/main.rs, line 2.
(gdb) run
Starting program: /home/a/tmp/foo/target/debug/foo
Warning:
Cannot insert breakpoint 1.
Cannot access memory at address 0x7a44
(gdb)
I also tried setting the breakpoint using b src/main.rs:2 as well as running just gdb instead of the Rust wrapper rust-gdb both of which resulted in the same outcome. Am I doing this properly?
System Information
/home/a/tmp/foo(HEAD)
09/19/2021 09:07:48.200 AM> uname -a
Linux a 5.13.15_1 #1 SMP Fri Sep 10 16:52:33 UTC 2021 x86_64 GNU/Linux
/home/a/tmp/foo(HEAD)
09/19/2021 09:07:51.291 AM> rustc --version
rustc 1.55.0 (c8dfcfe04 2021-09-06)
/home/a/tmp/foo(HEAD)
09/19/2021 09:07:53.955 AM> gdb --version
GNU gdb (GDB) 10.2
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
I managed to get it working by uninstalling the installed gdb (which was obtained from the Nixpkgs repository) and replacing it with gdb from the Void Linux musl repository. I suspect the gdb from Nixpkgs was built with glibc and is incompatible with the compiled Rust program which was compiled to use musl instead. Usually, the Bedrock Linux userspace that I use allows me to use programs built with different C libraries together, but in this case I guess I needed GDB to be using the same C library as the thing it's trying to debug.
I'm practicing reversing a stripped arm binary (that I wrote) and found that when I set a breakpoint at say 0x010451, and run the program, gdb spins forever until I hit ctrl+c. When I do, the current pc is at the address, but I can't continue the program.
When I set the breakpoint to 0x010450, gdb hits the breakpoint fine, but the instructions are being decoded as non-thumb instructions.
Is this expected? A bug? I will try to upload examples later today.
Version info (under qemu usermode emulation):
debian#debian-arm:~/lab$ gdb --version
GNU gdb (Debian 8.2.1-2+b3) 8.2.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
debian#debian-arm:~/lab$ uname -a
Linux debian-arm 4.19.0-10-armmp-lpae #1 SMP Debian 4.19.132-1 (2020-07-24) armv7l GNU/Linux
I am trying to cross-compile Linux for QEMU (RV64G ISA, lp64d ABI, Virt machine) using Buildroot. But apparently, GDB has been removed from buildroot version I'm using (2019.08), and is listed under the legacy list.
My objective is to be able to run RISC-V Linux application (in user-mode and softmmu) and with GDB debugging. I was able to build and run RISC-V apps using QEMU in both modes. But I didn't find a way to generate GDB like the other host utilities. Any ideas on how to do that?
A possible procedure for building a riscv64-linux-gnu-gdb from scratch would be :
PREFIX=$(pwd)/gdb-8.3.1-riscv64-linux-gnu
wget ftp://ftp.gnu.org/gnu/gdb/gdb-8.3.1.tar.xz
tar Jxf gdb-8.3.1.tar.xz
mkdir gdb
cd gdb
../gdb-8.3.1/configure --program-prefix=riscv64-linux-gnu- -with-tui --target=riscv64-linux-gnu --prefix=${PREFIX}
make all install
cd -
Build artifacts will located in $(pwd)/gdb-8.3.1-riscv64-linux-gnu:
ls -gG gdb-8.3.1-riscv64-linux-gnu/bin/riscv64-linux-gnu-gdb
-rwxr-xr-x 1 80395824 Sep 26 14:16 gdb-8.3.1-riscv64-linux-gnu/bin/riscv64-linux-gnu-gdb
gdb-8.3.1-riscv64-linux-gnu/bin/riscv64-linux-gnu-gdb --version
GNU gdb (GDB) 8.3.1
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
If you don't want to build GDB with the TUI interface, remove --with-tui from the ./configure command.
I hope this helps.
gdb has certainly not been removed from Buildroot! However, back when the RISC-V support was added in Buildroot, the gdb support was not included, and therefore BR2_PACKAGE_HOST_GDB_ARCH_SUPPORTS depends on !BR2_riscv, which hides gdb when the RISC-V architecture is selected.
So one would need to see if there is an upstream version of gdb that supports RISC-V, and if there is, remove the !BR2_riscv dependency, and add the appropriate dependencies to prevent the user from selecting older gdb versions that don't have RISC-V support.
$ file app
app: Mach-O universal binary with 2 architectures
app (for architecture i386): Mach-O executable i386
app (for architecture x86_64): Mach-O 64-bit executable x86_64
$ gdb app
GNU gdb (GDB) 7.6
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin13.0.0".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
"app": not in executable format: File format not recognized
$ file test
test: Mach-O 64-bit executable x86_64
$ gdb test
GNU gdb (GDB) 7.6
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin13.0.0".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /Users/dmulder/test...Reading symbols from /Users/dmulder/test.dSYM/Contents/Resources/DWARF/test...done.
done.
Why would the 64bit binary succeed, but the 64+32 binary fail?
Unfortunately, the non-Apple version of GNU gdb is currently unable to debug universal (or 'fat') binaries (ones that contain both 32-bit and 64-bit executables).
One option is to use lipo to extract a single architecture and run gdb on that:
lipo -thin x86_64 -output app-x86_64 ./app
or
lipo -thin i386 -output app-i386 ./app
If you'd prefer to debug the combined executable, you could try using LLDB, or an Apple version of gdb.
As OP commented, using Apple's gdb will fix the problem.
Here are instructions to build Apple gdb 6.3.50.20050815-cvs from source on OS 10.9:
NOTE: You will need to install Xcode and set up a build environment. If you have Homebrew installed, run brew doctor to see if "Your system is ready to brew."
Download the gdb-1822 source tarball from: http://opensource.apple.com/tarballs/gdb/gdb-1822.tar.gz
Extract this into a temporary directory. Open a terminal and cd into gdb-1822/src.
Run the configure script:
./configure --prefix="$HOME/.local/stow/gdb-1822" --disable-debug --disable-dependency-tracking --with-system-readline
(The last three configure arguments are from the homebrew-dupes formula: https://github.com/Homebrew/homebrew-dupes/blob/master/gdb.rb )
Run make:
make
make install
Follow the instructions at https://sourceware.org/gdb/wiki/BuildingOnDarwin#Creating_a_certificate to create a gdb-cert code signing certificate.
cd into $HOME/.local/stow/gdb-1822/bin and sign the gdb executable:
codesign -s gdb-cert gdb
cd into $HOME/.local/stow and stow the gdb-1822 folder:
stow gdb-1822
Add $HOME/.local/bin to your PATH and either restart the terminal or clear Bash's cache to the location of gdb:
hash -d gdb
From this link: http://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
-dH Produce a core dump whenever an error occurs.
So, I compiled a program with a syntax error and the core file was generated. How can that core file be used now? GDB can't be invoked since any executable has not been generated, yet.
[11:11:12 Wed Apr 27]
~/junk1 $ls
core hell.c
[11:11:15 Wed Apr 27]
~/junk1 $gcc -g hell.c -dH
hell.c: In function ‘main’:
hell.c:4: error: expected ‘;’ before ‘}’ token
gcc: Internal error: Aborted (program cc1)
Please submit a full bug report.
See <http://bugs.opensuse.org/> for instructions.
[11:11:36 Wed Apr 27]
~/junk1 $ls
core hell.c
[11:12:09 Wed Apr 27]
~/junk1 $gdb cc1 core
GNU gdb (GDB) SUSE (6.8.91.20090930-2.4)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-suse-linux".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
***cc1: No such file or directory.***
Missing separate debuginfo for the main executable file
Try: zypper install -C "debuginfo(build-id)=41f1efcceccfa5fa0b3476021c731c489547f86e"
Core was generated by `/usr/lib64/gcc/x86_64-suse-linux/4.4/cc1 -quiet hell.c -quiet -dumpbase hell.c'.
Program terminated with signal 6, Aborted.
#0 0x00007fb1b01654e5 in ?? ()
(gdb)
The GDB says: cc1: No such file or directory, in the above output.
How I am supposed to use that core file?
I think that switch is to help debug gcc, not your program. The page you link to starts like this:
3.9 Options for Debugging Your Program or GCC
GCC has various special options that are used for debugging either your program or GCC:
Emphasis mine.
The cc1 program is an internal part of GCC, it is probably somewhere under /usr/lib/ or /usr/libexec/.
gdb -c corefile should work. I haven't had to use the -dH option, so not sure how useful it is in helping with debugging.