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648f6099d4
A number of targets use assignments like:
. = DATA_SEGMENT_RELRO_END (SIZEOF (.got.plt) >= 12 ? 12 : 0, .);
(from i386) in linker scripts to put the end of the relro segment past
the header in .got.plt. Examination of testcases like those edited by
this patch instead sees the end of the relro segment being placed at
the start of .got.plt. For the i386 pie1 test:
[ 9] .got.plt PROGBITS 00002000 001000 00000c 04 WA 0 0 4
GNU_RELRO 0x000f90 0x00001f90 0x00001f90 0x00070 0x00070 R 0x1
A map file shows:
.dynamic 0x0000000000001f90 0x70
*(.dynamic)
.dynamic 0x0000000000001f90 0x70 tmpdir/pie1.o
0x0000000000001f90 _DYNAMIC
.got 0x0000000000002000 0x0
*(.got)
.got 0x0000000000002000 0x0 tmpdir/pie1.o
*(.igot)
0x0000000000002ff4 . = DATA_SEGMENT_RELRO_END (., (SIZEOF (.got.plt) >= 0xc)?0xc:0x0)
.got.plt 0x0000000000002000 0xc
*(.got.plt)
.got.plt 0x0000000000002000 0xc tmpdir/pie1.o
0x0000000000002000 _GLOBAL_OFFSET_TABLE_
The DATA_SEGMENT_RELRO_END value in the map file is weird too. All of
this is triggered by SIZEOF (.got.plt) being evaluated wrongly as
zero. Fix it by taking into account the action of
lang_reset_memory_regions during relaxation.
* ldexp.c (fold_name <SIZEOF>): Use rawsize if size has been reset.
* ldlang.c (lang_size_sections_1): Don't reset processed_vma here.
* testsuite/ld-i386/pie1.d: Adjust to suit.
* testsuite/ld-x86-64/pr20830a.d: Likewise.
* testsuite/ld-x86-64/pr20830b.d: Likewise.
* testsuite/ld-x86-64/pr21038a.d: Likewise.
* testsuite/ld-x86-64/pr21038b.d: Likewise.
* testsuite/ld-x86-64/pr21038c.d: 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.
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.