Two patches from Nelson Chu.
It is better to use the linker's callback functions to handle the link time
error when relocating. The unresolved relocation error can be regarded as
an unsupported relocation. To make user easier to understand different errors,
we need to extend the current error message format of the callback function
since the format is fixed.
bfd/
* elfnn-riscv.c (riscv_elf_relocate_section): Use asprintf to extend
the error message if needed, and then store the result into the
`msg_buf`. Finally, remember to free the unused `msg_buf`. All error
message for the dangerous relocation should be set before we call the
callback function. If we miss the error message since linker runs out
of memory, we should set the default error message for the error.
ld/
* testsuite/ld-riscv-elf/lib-nopic-01a.s: Create the shared library
lib-nopic-01a.so, it will be linked with lib-nopic-01b.s.
* testsuite/ld-riscv-elf/lib-nopic-01b.s: Add new test for the
unresolved relocation. Link the non-pic code into a shared library
may cause the error.
* testsuite/ld-riscv-elf/lib-nopic-01b.d: Likewise.
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Run the new test only when
the shared library is supported.
R_RISCV_CALL, R_RISCV_JAL and R_RISCV_RVC_JUMP are pc-relative relocation.
For now, we do not allow the object with these relocation links into a shared
library since the referenced symbols may be loaded to the places that too far
from the pc. We can improve the error message for these unsupported relocation
to notice user that they should recompile their code with `fPIC`.
bfd/
* elfnn-riscv.c (riscv_elf_relocate_section): Report the error message
that user should recompile their code with `fPIC` when linking non-pic
code into shared library.
ld/
* testsuite/ld-riscv-elf/lib-nopic-01b.d: Update the error message.
Change-Id: Ib3347a0a6fa1c2b20a9647c314d5bec2c322ff04
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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.
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