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Steps to get GDB actually working in April 2021 on macOS (Intel x86-64 only)

Debug with GDB on macOS 11

The big reason to do this is that LLDB has no ability to "follow-fork-mode child", in other words, a multi-process target that doesn't have a single-process mode (or, a bug that only manifests when in multi-process mode) is going to be difficult or impossible to debug, especially if you have to run the target over and over in order to make the bug manifest. If you have a repeatable bug, no big deal, break on the fork from the parent process and attach to the child in a second lldb instance. Otherwise, read on.

Install GDB

Don't make the mistake of thinking you can just brew install gdb. Currently this is version 10.2 and it's mostly broken, with at least two annoying bugs as of April 29th 2021, but the big one is https://sourceware.org/bugzilla/show_bug.cgi?id=24069

$ xcode-select install  # install the XCode command-line tools
$ brew install --force --build-from-source domq/gdb/gdb  # a patched version based on 10.1

It's now installed at /usr/local/bin/gdb.

Create and Install a Self-Signed Code-Signing Certificate

  1. Start the Keychain Access application, found in /Applications/Utilities.
  2. From the Keychains list on the left, right-click on the System item and select Unlock Keychain "System".
  3. Choose Keychain Access > Certificate Assistant > Create a Certificate... from the menu.
  4. Choose a name (e.g. gdb-cert), set Identity Type to Self Signed Root, set Certificate Type to Code Signing and select the Let me override defaults. Click several times on Continue until you get to the Specify a Location For The Certificate screen, then set Keychain to System.
  5. If for some reason you create the certificate in the System keychain directly, create it in the Login keychain, then export it. You can then import it into the System keychain.
  6. Finally, using the context menu for the certificate, select Get Info, open the Trust item, and set Code Signing to Always Trust.
  7. From the Keychains list on the left, right-click on the System item and select Lock Keychain "System".
  8. You must quit the Keychain Access application and restart the system, in order to use the certificate.

Create the entitlements plist file (for macOS 10.14 and newer)

We'll call it gdb-entitlement.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>com.apple.security.cs.allow-jit</key>
    <true/>
    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
    <true/>
    <key>com.apple.security.cs.allow-dyld-environment-variables</key>
    <true/>
    <key>com.apple.security.cs.disable-library-validation</key>
    <true/>
    <key>com.apple.security.cs.disable-executable-page-protection</key>
    <true/>
    <key>com.apple.security.cs.debugger</key>
    <true/>
    <key>com.apple.security.get-task-allow</key>
    <true/>
</dict>
</plist>

Codesign and entitle the GDB executable

$ codesign --entitlements gdb-entitlement.xml -fs gdb-cert $(which gdb)

This seems to work even though that's Homebrew's link to the actual file on disk:

% ls -la $(which gdb)
lrwxr-xr-x  1 mmyers  admin  26 Apr 28 16:16 /usr/local/bin/gdb -> ../Cellar/gdb/10.2/bin/gdb
% codesign -vvv /usr/local/Cellar/gdb/10.2/bin/gdb
/usr/local/Cellar/gdb/10.2/bin/gdb: valid on disk
/usr/local/Cellar/gdb/10.2/bin/gdb: satisfies its Designated Requirement

Finally, Run GDB

$ gdb hello_world
(gdb) break main
(gdb) run

Troubleshooting

  • GDB will not understand "fat" executables. You can "lipo -thin x86_64" them.
  • If you tried debugging with gdb, but you get a "No symbol table is loaded" error, you might need to compile programs with the -ggdb option in gcc. I didn't have this issue personally.
  • If after hitting run in gdb, you get "Starting program: /path/to/your/executable [args] [New Thread 0x2303 of process 795]" followed by a blank line which does not respond to anything, then you have hit GDB bug 24069. Check that you built the patched version from source.
@michaelschem
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@jacksonwelsh did you ever find a solution? I'm having the same issue.

@gromgit
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gromgit commented Feb 21, 2022

@michaelschem As @phil-blain already mentioned:

GDB does not yet support the M1 chip

The instructions above that do work are for GDB on Intel macOS.

@phil-blain
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phil-blain commented Mar 3, 2022

Hi everyone, the fixes that Dominique Quatravaux (@domq) incorporated in their fork of GDB, made available in the Homebrew tap linked above by @mike-myers-tob (at https://github.com/domq/homebrew-gdb), were merged recently to the upstream GDB project:

This means that you should be able to get a working GDB on recent macOS by building from source, which should be as easy as this:

date="$(date +%Y%m%d)"
curl -sSLO https://sourceware.org/pub/gdb/snapshots/current/gdb-12.0.50.${date}.tar.xz
tar xf gdb-12.0.50.${date}.tar.xz
mkdir build
cd build
../gdb-12.0.50.${date}/configure \
    --disable-unit-tests         \
    --disable-binutils           \
    --without-guile
make -j
make install
echo 'set startup-with-shell off' >> $HOME/.gdbinit

and then signing the executable as mentioned above. Disabling unit-tests should not affect GDB's functionality and is required to work around this bug.

It would be really great if interested people could try it and see if the hang is resolved. It is from my testing on macOS 10.15 but I do not have access to other versions to test. Please do try it and report back on the bugzilla issue (https://sourceware.org/bugzilla/show_bug.cgi?id=24069) if the hang is not resolved.

EDIT changed the commands above to use date so they can be copy pasted as-is.
EDIT added --without-guile

@zouhairm
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zouhairm commented Mar 7, 2022

Running into this issue. I'm on macOS 10.15.7.
Tried the following:

  • downloaded gdb-12.0.50.20220307 & unzipped
mkdir build
cd build
../gdb-12.0.50.20220307/configure --with-pydebug --disable-unit-tests   --disable-binutils
make -j

Getting this error:

../../gdb-12.0.50.20220307/gdb/guile/guile.c:676:5: error:
      'scm_install_gmp_memory_functions' is deprecated [-Werror,-Wdeprecated-declarations]
    scm_install_gmp_memory_functions = 0;
    ^
/usr/local/Cellar/guile/3.0.8/include/guile/3.0/libguile/deprecated.h:164:1: note:
      'scm_install_gmp_memory_functions' has been explicitly marked deprecated here
SCM_DEPRECATED int scm_install_gmp_memory_functions;
^
/usr/local/Cellar/guile/3.0.8/include/guile/3.0/libguile/scm.h:743:50: note: expanded from
      macro 'SCM_DEPRECATED'
# define SCM_DEPRECATED  SCM_API __attribute__ ((__deprecated__))
                                                 ^
1 error generated.
make[2]: *** [guile/guile.o] Error 1
make[2]: *** Waiting for unfinished jobs....
``

@phil-blain
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If you don’t need Guile scripting capabilities, try removing the build directory and rerunning configure with --without-guile

@iceice
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iceice commented Mar 27, 2022

Hi everyone, the fixes that Dominique Quatravaux (@domq) incorporated in their fork of GDB, made available in the Homebrew tap linked above by @mike-myers-tob (at https://github.com/domq/homebrew-gdb), were merged recently to the upstream GDB project:

This means that you should be able to get a working GDB on recent macOS by building from source, which should be as easy as this:

date="$(date +%Y%m%d)"
curl -sSLO https://sourceware.org/pub/gdb/snapshots/current/gdb-12.0.50.${date}.tar.xz
tar xf gdb-12.0.50.${date}.tar.xz
mkdir build
cd build
../gdb-12.0.50.${date}/configure \
    --disable-unit-tests         \
    --disable-binutils           \
    --without-guile
make -j
make install
echo 'set startup-with-shell off' >> $HOME/.gdbinit

and then signing the executable as mentioned above. Disabling unit-tests should not affect GDB's functionality and is required to work around this bug.

It would be really great if interested people could try it and see if the hang is resolved. It is from my testing on macOS 10.15 but I do not have access to other versions to test. Please do try it and report back on the bugzilla issue (https://sourceware.org/bugzilla/show_bug.cgi?id=24069) if the hang is not resolved.

EDIT changed the commands above to use date so they can be copy pasted as-is. EDIT added --without-guile

Thanks for @phil-blain tutorial, but the gdb hangs on macOS Catalina(10.15.7) at the very first excution, run gdb again, it works well.

How can I avoid it?

@phil-blain
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Thanks for @phil-blain tutorial, but the gdb hangs on macOS Catalina(10.15.7) at the very first excution, run gdb again, it works well.

How can I avoid it?

Thanks for trying it! I also noticed that behaviour. Unfortunately I can't tell you how to avoid it since it appears the GDB bug is not yet completely fixed. The only way to avoid it would be to fix GDB. This would require understanding the Darwin/Mach kernel debug API and trying to assess what goes wrong in the GDB code base. Since GDB works correctly on macOS 10.13 and below, I'm assuming something changed in the macOS kernel behaviour between 10.13 and 10.14 which leads to the wrong behaviour being observed here...

@hitzhangjie
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hitzhangjie commented Apr 10, 2022

Can anyone submit a built gdb binary here, I am using macOS 10.15.7. My network is so slow to pull the gdb source code.


I solved this by:

  1. download the source code zip file from https://github.com/bminor/binutils-gdb.git,
    unzip the zipfile to ./binutils-gdb-master
  2. then try to build from master HEAD
mkdir build
cd build
../binutils-gdb-master/configure \
    --disable-unit-tests         \
    --disable-binutils           \
    --without-guile
make -j8

the built gdb binary is put here: ./gdb/gdb

Because I want to make package management simpler, so I don't want to run make install to install the gdb and other files.

ps: there's no make uninstall target in the Makefile, if you want to remove all installed files, try this:

make install DESTDIR=/tmp/gccinst
find /tmp/gccinst | sed -e s,/tmp/gccinst,, | \
(while read F; do rm "$F"; done)
  1. I then run brew install gdb to install the homebrew latest version, then I replace the gdb binary by:
cp ./gdb/gdb /usr/local/Cellar/gdb/11.2/bin/gdb -f
  1. Then codesign mentioned above, OK, I put it here for convenience:
    write a gdb-entitlement.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>com.apple.security.cs.allow-jit</key>
    <true/>
    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
    <true/>
    <key>com.apple.security.cs.allow-dyld-environment-variables</key>
    <true/>
    <key>com.apple.security.cs.disable-library-validation</key>
    <true/>
    <key>com.apple.security.cs.disable-executable-page-protection</key>
    <true/>
    <key>com.apple.security.cs.debugger</key>
    <true/>
    <key>com.apple.security.get-task-allow</key>
    <true/>
</dict>
</plist>

then run following command to codesign:

sudo codesign --entitlements gdb-entitlement.xml -fs gdb-cert $(which gdb)

If you don't have a gdb-cert created before, run following command to create one:

# download the script
https://github.com/conda-forge/gdb-feedstock/blob/main/recipe/macos-codesign/macos-setup-codesign.sh

# replace the certificate name
sed -i 's/gdb-codesign/gdb-cert/g' macos-setup-codesign.sh

# run the script to create the certificate and trust it
./macos-setup-codesign.sh

# check the certificate is create or not
security find-certificate -p -c gdb-cert | openssl x509 -checkend 0
or
security find-certificate -p -c gdb-cert |openssl x509 -noout -text\
  1. then you can start your debugging, it works.

@phil-blain
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GDB 12.1 was released last weekend, which includes the patches mentioned above. You can build it yourself from the tarball, or use brew install gdb since Homebrew has already built this new version.

@petrstepanov
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@mike-myers-tob thank you for this write up! I also confirm that above approach works with Eclipse 2022-03 (4.23.0) and GNU gdb (GDB) 12.1 installed from brew install gdb

@michaelschem
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The hint is in the error x86_64 architecture is required for this software., you're on an M1 mac. Not gonna work.

@4nuG
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4nuG commented Aug 21, 2022

@michaelschem im on a 2022 m2 Mac and I get the same error:
% brew install gdb
gdb: The x86_64 architecture is required for this software.

@michaelschem
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@4nuG same problem. All mac chips (those starting with M) are arm and not x86_64.

@siddharth7061
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Hi I am using macOS Catalina 10.15.7
I had to create the certificate in login as it was showing error while doing it in system. How do i import it to system, please explain.

@mayakrunal
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@siddharth7061 I think you can just import it into key chain, if it's on your local laptop.

https://support.apple.com/guide/keychain-access/add-certificates-to-a-keychain-kyca2431/mac

@mayakrunal
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@ferdnyc
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ferdnyc commented Oct 21, 2022

# download the script
https://github.com/conda-forge/gdb-feedstock/blob/main/recipe/macos-codesign/macos-setup-codesign.sh

# replace the certificate name
sed -i 's/gdb-codesign/gdb-cert/g' macos-setup-codesign.sh

@hitzhangjie

Note that, at least with the current version of https://github.com/conda-forge/gdb-feedstock/blob/main/recipe/macos-codesign/macos-setup-codesign.sh, that sed command should be:

sed -i 's/gdb_codesign/gdb-cert/g' macos-setup-codesign.sh

Since the script (now?) uses an underscore instead of a dash.

Probably makes sense to do this, in fact:

sed -i 's/gdb_codesign/gdb_cert/g' macos-setup-codesign.sh

And then use the name gdb_cert instead.

@optimux
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optimux commented Nov 27, 2022

Hang issue:
If after hitting run in gdb, you get "Starting program: /path/to/your/executable [args] [New Thread 0x2303 of process 795]" followed by a blank line which does not respond to anything, then you have hit GDB bug 24069.

This problem has an easy fix, type in terminal:
echo "set startup-with-shell-off" >> ~/.gdbinit
source ~/.gdbinit

Restart gdb you'll find it's working. This issue is quite annoying, I spent weeks on this but failed. Tools must be easy to use not to keep us from working!

@optimux
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optimux commented Dec 4, 2022

Hi guys,
I just ran into a wired issue: <error reading variable: failed to get range bounds>. For variables of size 1 in local subroutines or shared from other modules, I can print its value; whereas for variables of size >1 (like 2D arrays or 1D vector), either in local subroutines or from shared modules, it says error reading variable: failed to get range bounds when I tried to print. Do you guys have any ideas? This is quite annoying.

info: macOS Monterey 12.0.1 + gdb 12.1 + intel chip + fortran90

The same code works properly on CentOS9 + gdb 10.2.

Thanks!

@phil-blain
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Hi @optimux, this looks like a general regression in GDB, not specific to macOS. If you can replicate it (using the same GDB version) on Linux, then I encourage you to report it to the GDB bug tracker, see:

@ken-salterdiazsolutions
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ken-salterdiazsolutions commented Jan 3, 2023

I'm running gdb 12.1 from brew install gdb. I have my .gdbinit file with set startup-with-shell off. I have setup Visual Studio Code to use gdb. It launches and I see this:

=thread-group-added,id="i1"
GNU gdb (GDB) 12.1
Copyright (C) 2022 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-darwin22.1.0".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".
=cmd-param-changed,param="startup-with-shell",value="off"
Warning: Debuggee TargetArchitecture not detected, assuming x86_64.
=cmd-param-changed,param="pagination",value="off"
[New Thread 0x2303 of process 42682]

and there it does nothing else. Any thoughts?

@ken-salterdiazsolutions
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ken-salterdiazsolutions commented Jan 3, 2023

Additionally, if I try to debug outside of Visual Studio Code, I get this:

GNU gdb (GDB) 12.1
Copyright (C) 2022 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-darwin22.1.0".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from greetings...
Reading symbols from /Users/kensalter/repos/nim/bin/greetings.dSYM/Contents/Resources/DWARF/greetings...
(gdb) run
Starting program: /Users/kensalter/repos/nim/bin/greetings 
[New Thread 0x2703 of process 42833]

^C[New Thread 0x2403 of process 42833]
warning: unhandled dyld version (17)
Server listening on port 8080

Notice, I have to feed a Command+C to kill the shell task so that my program actually runs.

@ferdnyc
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ferdnyc commented Jan 4, 2023

@ken-salterdiazsolutions

All of the previous times "unhandled dyld version" has come up, it's been an issue of GDB just plain being out of date with the latest Apple changes to the dynamic-loading API. Whether that requires a simple version bump in a macro, or more involved changes to the code to support new/modified API features, is an open question. But if you're seeing that, it's likely you need a newer gdb... assuming a version even exists, yet, which has been patched to support dyld version 17.

@ken-salterdiazsolutions
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@ken-salterdiazsolutions

All of the previous times "unhandled dyld version" has come up, it's been an issue of GDB just plain being out of date with the latest Apple changes to the dynamic-loading API. Whether that requires a simple version bump in a macro, or more involved changes to the code to support new/modified API features, is an open question. But if you're seeing that, it's likely you need a newer gdb... assuming a version even exists, yet, which has been patched to support dyld version 17.

It is the latest I know of from brew (12.1)..anyway I think I've given up. If I run it via cmd line and use the Command+C to get to the actual program, because the program is written in Nim, the vars and function names are mangled. Was investigating if Nim would be something to have in my toolkit, but on the Mac at least it seems to be a PITA as far as debugging is concerned. I had also tried LLDB but no love there either. Ah well...thanks for the reply!

@ferdnyc
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ferdnyc commented Jan 5, 2023

@ken-salterdiazsolutions

Mmm, well, I certainly don't know a whole lot about Nim. From a quick skim online, I gather that it basically compiles down to source code in a number of different languages (C, C++, JS, etc.), but C by default. If you're seeing mangled symbols, sounds like it may be compiling to C++ (or maybe Nim does its own mangling).

You've probably seen most of these already, but...

This blog post recommends using all of these options on the nim c command line, for generating debuggable binaries:

$ nim c -d:debug --lineDir:on --debuginfo --debugger:native myprogram.nim

This documentation page also suggests including --opt:none (but that may be the default for -d:debug anyway). It sounds like --debugger:native is the really important flag.

It also looks like there are pre-made convenience wrappers available, when using gdb with Nim:

Compile this code with --debugger:native and load it to nim-gdb.

nim c --debugger:native test.nim
nim-gdb test

If you cannot find nim-gdb, you can download Nim/bin/nim-gdb and Nim/tools/nim-gdb.py from Nim repository. If you don't use nim-gdb, execute source Nim/tools/nim-gdb.py command after you run gdb. nim-gdb is a bash script that execute GDB and let GDB load Nim/tools/nim-gdb.py. And nim-gdb.py is a Python script that make GDB print Nim variables nicely.

@domq
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domq commented Jan 19, 2023

Many thanks @mike-myers-tob and all participants to this gist. I just updated the relevant Wiki page with the correct and up-to-date contents for gdb-entitlement.xml as seen above.

@Vegz78
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Vegz78 commented Jan 19, 2023

Great work!!!

@VenkyDevHub
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Great!!! It is working on my Mac. Thanks very much for this procedure.

@gpertea
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gpertea commented Aug 24, 2023

No luck here, Catalina 10.15.7, latest gdb 13.2 installed with brew, trying to debug C++ program in latest Eclipse. When I try debugging, it just runs ignoring any breakpoints I set. If I check the option to stop at "main", it does stop as the debug session starts, but in a nonsensical place, and the call stack also does not make any sense. The dreaded "unhandled dlyd version" issue might have something to do with this failure, I guess..

[New Thread 0x2803 of process 67174]
[New Thread 0x1e03 of process 67174]
[New Thread 0x2503 of process 67174]
warning: unhandled dyld version (16)

Thread 3 hit Temporary breakpoint 4.1, 0x00000001000f1f75 in ....

Same behavior no matter what compiler I use (tried: Xcode clang++ 12.0 and brew g++ 13.1)

@PrabhuUdurg
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Sonoma 14.4.1 with gdb 14.2 still the same problem as in @gpertea case above

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