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c628f812eb
Consider the the pcgp-relax-02 testcase,
.text
.globl _start
_start:
.L1: auipc a0, %pcrel_hi(data_a)
.L2: auipc a1, %pcrel_hi(data_b)
addi a0, a0, %pcrel_lo(.L1)
addi a1, a1, %pcrel_lo(.L2)
.data
.word 0x0
.globl data_a
data_a:
.word 0x1
.section .rodata
.globl data_b
data_b:
.word 0x2
If the first auipc is deleted, but we are still building the pcgp
table (connect the high and low pcrel relocations), then there is
an aliasing issue that we need some way to disambiguate which of
the two symbols we are targeting. Therefore, Palmer thought of a
way to use R_RISCV_DELETE to split this into two phases, so we
could resolve the addresses before creating the ambiguities.
This patch just add the ld testcase for the above case, in case we
have changed something but break this.
ld/
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Renamed pcgp-relax
to pcgp-relax-01, and added pcgp-relax-02.
* testsuite/ld-riscv-elf/pcgp-relax-01.d: Renmaed from pcgp-relax.
* testsuite/ld-riscv-elf/pcgp-relax-01.s: Likewise.
* testsuite/ld-riscv-elf/pcgp-relax-02.d: New testcase.
* testsuite/ld-riscv-elf/pcgp-relax-02.s: Likewise.
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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