Rework ifunc support to address a number of short comings:
- Move to a shared _rtld_call_ifunc for rel and rela architectures
- Architectures using rel format must patch IRELATIVE non-PLT
relocations like RELATIVE in additition to the later ifunc handling
- Consistently record the delta to the end of the relocation group for
non-PLT IRELATIVE relocations

Hidden ifunc is now supported on all ifunc platforms, even when using
-fno-plt. The combination of -fno-plt and relro is broken due to
incorrect GNU ld output though.

branches: 1.14.44;
simplify the logic for compat ld.elf_so and move it here. we now can
find the libc objdir for multiple compat ld.elf_so's, too.

rename LD32DIR to MLIBDIR.

move the defines for RTLD_ARCH_SUBDIR into a sub-sub-makefile so we can
grab these values via reach-over more easily.

branches: 1.11.2;
if LD32DIR is defined:
- look in src/compat/lib/libc for libc_pic.
- define RTLD_ARCH_SUBDIR to "i386" or "sparc" for amd64 and sparc64
builds, respectively
if RTLD_ARCH_SUBDIR is defined, add this path before
RTLD_DEFAULT_LIBRARY_PATH in the default search path.

Explicitly prefix ld(1) options in LDFLAGS with "-Wl," rather than
using the ${LDFLAGS:@F@-Wl,$F@} make substitution because that breaks
if LDFLAGS is already set.

Move common LDFLAGS into Makefile from arch/*/Makefile.inc

Whitespace.

Remove vestiges of VARPSZ.

This ld script is no longer necessary.

Nuke RTLD_RELOCATE_SELF for SPARC.

branches: 1.4.2;
Grumble. Put compiler options back into CPPFLAGS for now, since
they're needed to build .S files with the correct PIC options.

XXX Really needs cleanup in <bsd.*.mk> to do this properly.

Don't put compiler options into CPPFLAGS.

We need to compile with -DVARPSZ, because the sparc has a variable page
size depending on arch. Make it an error to compile without it. This
caused -lposix linked programs to fail.

Work in progress (does not work yet).

simplify the logic for compat ld.elf_so and move it here. we now can
find the libc objdir for multiple compat ld.elf_so's, too.

branches: 1.1.2;
move the defines for RTLD_ARCH_SUBDIR into a sub-sub-makefile so we can
grab these values via reach-over more easily.

This ld script is no longer necessary.

Nuke RTLD_RELOCATE_SELF for SPARC.

ld.elf_so(1): Nix trailing whitespace.

No functional change intended.

ld.elf_so: Cite reference for SPARC ELF relocations

PR lib/58455: Missing references for processor-specific ELF
relocation semantics

branches: 1.58.2;
Fix debug code

Fix interactions of initial-exec TLS model and dlopen

(1) If an initial-exec relocation was used for a non-local symbol
(i.e. the definition of the symbol is in a different DSO), the
computation of the static TLS offset used the wrong DSO.
This would effectively mean the wrong address was computed
(PR toolchain/50277, PR pkg/57445).

Fix this by forcing the computation of the correct DSO (the one defining
the symbol).

This code uses __UNCONST to avoid the vast interface changes for this
special case.

(2) If symbols from a DSO loaded via dlopen are used with both
global-dynamic/local-dynamic and initial-exec relocations AND
a initial-exec relocation was resolved first in a thread, a split brain
situation could exist where the dynamic relocations would use one memory
block (separate allocation) and the initial-exec relocations the static
per-thread TLS space.

(3) If the initial-exec relocation in (2) is seen after any thread has
already used a GD/LD allocation, bail out. Since IE relocations are used
only in the GOT, this will prevent the dlopen. This is a bit more
aggressive than necessary, but a full blown reference counting doesn't
seem to be justified.

follow the steps of Andrew Doran (ad) commit and fix more s/loose/lose/ typos.
also s/beyound/beyond/ and few others along the way, mainly in comments.

branches: 1.55.4; 1.55.12;
Rework ifunc support to address a number of short comings:
- Move to a shared _rtld_call_ifunc for rel and rela architectures
- Architectures using rel format must patch IRELATIVE non-PLT
relocations like RELATIVE in additition to the later ifunc handling
- Consistently record the delta to the end of the relocation group for
non-PLT IRELATIVE relocations

Hidden ifunc is now supported on all ifunc platforms, even when using
-fno-plt. The combination of -fno-plt and relro is broken due to
incorrect GNU ld output though.

Move the complex logic for dynamically writing branches from ld.elf_so
into a header for reuse in crt0.o for static ifunc support. Change the
existing logic for sparc64 to use the Bicc variant of ba,a as it allows
+-8MB displacement compared to the BPcc variant's +-1MB. Teach the sparc
variant the same trick for using ba,a and not sethi+jmp when possible.

Don't skip PLT processing for the main binary. It can still contain
ifunc references.

branches: 1.52.2;
Add sparc/sparc64 support for irelative relocations.

Add IRELATIVE support for ARM, X86 and PowerPC.

Replace COMBREL with just-in-time check in _rtld_relocate_nonplt_objects.

The COMBREL logic predates thread-safety of the dynamic linker and
breaks the use of shared locks for the common symbol lookup case. It is
unlikely to provide any benefit for lazy binding or PLT lookups, so
provide equivalent functionality in the non-PLT relocation handling loop
by checking if the symbol used by the current relocation is the same as
the one used during the last lookup. No inter-object cachine is done as
it is also unlikely to be benefical.

Testing with Firefox startup on AMD64 shows a small performance gain by
the new method.

Fix indentation.

branches: 1.48.8;
Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

branches: 1.47.22;
Add missing comma.

Add support for TLS relocations

Add basic locking to ld.elf_so.

Reduce header pollution for mdreloc.c. Make Obj_Entry argument of
_rtld_relocate_nonplt_objects non-const in preparation for TLS support.

PR/39240: Satoshi Suetake: Don't fail when attempting to resolve weak symbols
when we are doing immediate binding, leave them alone and they will be dealt
with later during lazy binding. From skrll@

Fix const issues (cast const pointers to "const uint8_t *" instead of "caddr_t")

NOTE: change based on ../i386/mdreloc.c 1.27
XXX: not compile tested

branches: 1.41.4; 1.41.6;
Refactor common code to _rtld_relocate_plt_object to i386 and arm so they
act like the other versions.
In _rtld_bind, if the result is 0, call _rtld_die.
Initialize _rtld_sym_zero.st_value to -_rtld_objself.maprelocbase. Now when
the symbol is resolved, st_value + maprelocbase will equal 0 and the above
check in _rtld_bind will fire and a call to NULL will be avoided.

branches: 1.40.2;
Remove clause 3 and 4 from TNF licenses

branches: 1.39.18;
in _rtld_bind() initialise result to appease GCC4.

Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

Add __RCSID.

KNF

Add LD_BIND_NOW support for sparc and remove some relocation types that
are not supposed to happen in 32bit code.
From Nick Hudson.

Add support for unaligned relocs on sparc, from PR 26858.
Should also fix PR 25901 and PR 18296.

branches: 1.33.4;
ANSIfy and de-__P().

Remove the `self' args to _rtld_relocate_objects() and
_rtld_relocate_nonplt_objects().

Remove a meaningless bit from a rdbg().

Make the stack frame 96 bytes, like GCC does.

Tweak the save instruction in the PLT stub rather than adding an instruction
to the binder entry stub...

For consistency, use Elf_Word* to point to code, not Elf_Addr*.

Push the _rtld_bind() interface into MD code -- it's just a trivial wrapper
anyway.

Nuke -DRTLD_RELOCATE_SELF and `dodebug' from orbit.

_rtld_bind_start() is not used in MI code, so declare it in the MD code.

Do the _rtld_relocate_nonplt_self() thing for SPARC.

Nuke RTLD_RELOCATE_SELF for SPARC.

Expand the comment about the R_TYPE(RELATIVE) special-case, as it's not quite
obvious from the code. Also, just do it all the time, as an optimization.

Make the reloc tables const.

Pass down an additional flag to _rtld_relocate_nonplt_objects() which
indicates whether we're relocating ld.elf_so itself. Use this in some places
rather than hackish tests on `dodebug'. (The Alpha and HPPA `dodebug' tests
were actually noops, because RTLD_RELOCATE_SELF is not set, and therefore
dodebug is always true.)

Re-poison a lot of consts, now that the mark shite is gone.

Split _rtld_relocate_plt_object() into two MD functions:
* _rtld_relocate_plt_lazy() fixes up all the relocs pointing to the PLT. (On
most platforms it just does a simple base-relative fixup; on SPARC it does
nothing.)
* _rtld_relocate_plt_object() does immediate binding for a PLT entry.
The basic gist is that this saves a bit of time on SPARC (where the iteration
through the pltrela table was gratuitous), and a little less time on all other
platforms. A whole lot of #ifdef'ed crap is moved out of reloc.c, too.

NOT tested on: hppa sh x86_64

Repair a slight biff I made earlier -- do not exit the loop in
_rtld_relocate_nonplt_objects() early.

Partially fix up some debug printf()s that don't need to use defobj.

A few things:
* Pass a symbol number to _rtld_find_symdef(), not a r_info.
* Don't try to do a symbol lookup when we find an unsupported relocation;
instead get the symbol name from the referencing object's strtab.
* Add preliminary support for `-z combreloc'-style startup optimization on
i386, `#ifdef COMBRELOC'.

Rename _rtld_relocate_nonplt_object() to _rtld_relocate_nonplt_objects(),
and push the outer loop into it. This actually shaves a couple % off startup
time at least on PCs.

Split _rtld_relocate_nonplt_object() into separate MD files.

Remove unused arguments of _rtld_find_symdef().

Make _rtld_setup_pltgot() a consistent interface on all platforms.

branches: 1.10.2;
Sync with <sys/exec_elf.h> rev. 1.45: ElfNN_RelA -> ElfNN_Rela.

branches: 1.9.4;
Make this more likely to compile with ld.elf_so changes. (But this is
untested.)

branches: 1.8.6;
fix rdbg macro args.

KNF

* Make changing the PLT slot entry (lazy function binding) thread-safe.
* Insert `iflush' instructions for the patched words in PLT entries.

Add comment on the necessity of having to look at implicit memory addends
even though the sparc architecture uses `Elf_Rela' structures exclusively.

Target bitmask for RELOC_RELATIVE should be a full word.
Also for RELOC_RELATIVEs, add in the memory contents in addition to r_addend.

Relative relocations should use addend.

Take care of `load address relative' relocations.
Ignore JMP_SLOTs in non-plt relocations.

Work in progress (does not work yet).

Remove clause 3 and 4 from TNF licenses

branches: 1.15.30;
Update copyright.

Adjust for the fact that the GOT is all 0s in new binutils -- do the trick of
disassembling a call to _DYNAMIC to determine its real address, and using the
first entry of the GOT as its base-relative address.

It's evil, but it works.

Make the stack frame 96 bytes, like GCC does.

Tweak the save instruction in the PLT stub rather than adding an instruction
to the binder entry stub...

Allocate space for the argument space area in both _rtld_start() and
_rtld_bind_start(). Not needed normally, but if we compile ld.elf_so with
-g, it blows up without this.

There is no need to save and restore a second register window in the binder
stub.

Update comments.

Pass the calculated relocation offset down to _rtld().

Do the _rtld_relocate_nonplt_self() thing for SPARC.

Indent branch delay instructions.

Nuke RTLD_RELOCATE_SELF for SPARC.

branches: 1.4.12;
- Use c style comments.
- & -> and
- align 4 in both functions for consistency.

Make mkdep succeed (use matching quotes in comment).

Implement rtld_bind() stub.
Fix startup code.

Work in progress (does not work yet).