Debugging with GDB (September 2007)

Appendix A: Installing GDB 329
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 gdb-199991101, you can build GDB in a separate directory
for a Sun 4 like this:
cd gdb-gdb-199991101
mkdir ../gdb-sun4
cd ../gdb-sun4
../gdb-gdb-199991101/configure sun4
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’.
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 de-
bugging 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 subdi-
rectories).
The Makefile that configure generates in each source directory also runs recursively.
If you type make in a source directory such as ‘gdb-gdb-199991101’ (or in a separate
configured directory configured with ‘--srcdir=dirname/gdb-gdb-199991101’), 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.
A.2 Specifying names for hosts and targets
The specifications used for hosts and targets in the configure script are based on a
three-part naming scheme, but some short predefined aliases are also supported. The full
naming scheme encodes three pieces of information in the following pattern:
architecture-vendor-os
For example, you can use the alias sun4 as a host argument, or as the value for target
in a --target=target option. The equivalent full name is ‘sparc-sun-sunos4’.
The configure script accompanying GDB does not provide any query facility to list
all supported host and target names or aliases. configure calls the Bourne shell script