Separate Objdir (Debugging with GDB)
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C.3 Compiling GDB in Another Directory
If you want to run GDB versions for several host or target machines, you need a different gdb
compiled for each combination of host and target. configure
is designed to make this easy by allowing you to generate each configuration in a separate subdirectory, rather than in the source directory. If your make
program handles the ‘VPATH
’ feature (GNU make
does), running make
in each of these directories builds the gdb
program specified there.
To build gdb
in a separate directory, run configure
with the ‘--srcdir
’ option to specify where to find the source. (You also need to specify a path to find configure
itself from your working directory. If the path to configure
would be the same as the argument to ‘--srcdir
’, you can leave out the ‘--srcdir
’ option; it is assumed.)
For example, with version 12.0.50.20211026-git, you can build GDB in a separate directory for a Sun 4 like this:
cd gdb-12.0.50.20211026-git mkdir ../gdb-sun4 cd ../gdb-sun4 ../gdb-12.0.50.20211026-git/configure make
When configure
builds a configuration using a remote source directory, it creates a tree for the binaries with the same structure (and using the same names) as the tree under the source directory. In the example, you’d find the Sun 4 library libiberty.a
in the directory gdb-sun4/libiberty
, and GDB itself in gdb-sun4/gdb
.
Make sure that your path to the configure
script has just one instance of gdb
in it. If your path to configure
looks like ../gdb-12.0.50.20211026-git/gdb/configure
, you are configuring only one subdirectory of GDB, not the whole package. This leads to build errors about missing include files such as bfd/bfd.h
.
One popular reason to build several GDB configurations in separate directories is to configure GDB for cross-compiling (where GDB runs on one machine—the host—while debugging programs that run on another machine—the target). You specify a cross-debugging target by giving the ‘--target=target
’ option to configure
.
When you run make
to build a program or library, you must run it in a configured directory—whatever directory you were in when you called configure
(or one of its subdirectories).
The Makefile
that configure
generates in each source directory also runs recursively. If you type make
in a source directory such as gdb-12.0.50.20211026-git
(or in a separate configured directory configured with ‘--srcdir=dirname/gdb-12.0.50.20211026-git
’), you will build all the required libraries, and then build GDB.
When you have multiple hosts or targets configured in separate directories, you can run make
on them in parallel (for example, if they are NFS-mounted on each of the hosts); they will not interfere with each other.
Next: Config Names, Previous: Running Configure, Up: Installing GDB [Contents][Index]