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README

README for LD

This is the GNU linker. It is distributed with other "binary utilities" which should be in ../binutils. See ../binutils/README for more general notes, including where to send bug reports.

There are many features of the linker:

  • The linker uses a Binary File Descriptor library (../bfd) that it uses to read and write object files. This helps insulate the linker itself from the format of object files.
  • The linker supports a number of different object file formats. It can even handle multiple formats at once: Read two input formats and write a third.
  • The linker can be configured for cross-linking.
  • The linker supports a control language.
  • There is a user manual (ld.texinfo), as well as the beginnings of an internals manual (ldint.texinfo).

Installation

See ../binutils/README.

If you want to make a cross-linker, you may want to specify a different search path of -lfoo libraries than the default. You can do this by setting the LIB_PATH variable in ./Makefile or using the --with-lib-path configure switch.

To build just the linker, make the target all-ld from the top level directory (one directory above this one).

Porting to a new target

See the ldint.texinfo manual.

Reporting bugs etc

See ../binutils/README.

Known problems

The Solaris linker normally exports all dynamic symbols from an executable. The GNU linker does not do this by default. This is because the GNU linker tries to present the same interface for all similar targets (in this case, all native ELF targets). This does not matter for normal programs, but it can make a difference for programs which try to dlopen an executable, such as PERL or Tcl. You can make the GNU linker export all dynamic symbols with the -E or --export-dynamic command line option.

HP/UX 9.01 has a shell bug that causes the linker scripts to be generated incorrectly. The symptom of this appears to be "fatal error - scanner input buffer overflow" error messages. There are various workarounds to this:

  • Build and install bash, and build with "make SHELL=bash".
  • Update to a version of HP/UX with a working shell (e.g., 9.05).
  • Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the emulparams script used exports any shell variables it sets.