Initially, since c6c37250e98f113755e0d787f7070e2ac80ce77e (in 1999),
in order to fix linking against Microsoft import libraries, ld did
internally rename members of such libraries. At that point, the
criteria for being considered a Microsoft import library was that
every archive member had the same name (no regard for exactly what
that name was).
This was later amended in 44dbf3639f127af46d569ad96b6242dfbc4c0a89
(in 2003) to allow for Microsoft import libraries with intermixed
static object files. At this point, the criteria were extended, so
that all members following the first member named *.dll either had
the exact same member name, or be named *.obj. (Curiously, this would
allow members with any name if it precedes the first one named *.dll.)
In practice, Microsoft style import libraries can contain
members for linking against more than one DLL (built by merging
multiple regular import libraries into one).
Instead of trying to do validation of the whole archive before
considering it a Microsoft style import library, relax the criteria
for doing the member renaming: If an archive member is named *.dll
and it contains .idata sections, assume that that member is a
Microsoft import file, and apply the renaming scheme.
This works for imports for any number of DLLs in the same library,
intermixed with other static object files (regardless of their
names), and vastly simplifies the code.
LLVM generates Microsoft style import libraries, and Rust builds
seem to bundle up multiple import libraries together with some
Rust specific static objects. This fixes linking directly against
them with ld.bfd.
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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.texi), as well as the
beginnings of an internals manual (ldint.texi).
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.texi 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.
Copyright (C) 2012-2022 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.
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