This option reverse input sections before assigning offsets to them.
This is useful to detect an unintended dependency between static
initializers in different translation units. C++ only guarantees that
static initializers are invoked from top to bottom in a single
translation unit, and it doesn't guaratee anything about the order of
initialization between translation units.
By (partially) reversing the contents of .init_array using
--reverse-sections, you can run your program with a completely
reversed initialization order.
The test expects an error when an object compiled with `-fno-PIC` is
linked with `-pie`, but that doesn't happen on aarch64.
Signed-off-by: Christoph Erhardt <github@sicherha.de>
This commit removes build-static.sh because statically-linked mold
executable can't generally dlopen a shared library and therefore can't
load the linker LTO plugin.
Now, build-dynamic.sh is renamed dist.sh and recommended for general
use.
I think we don't need to create a tar file for binary distribution
for each Linux distro. Instead, we can create mold executable that
works on most Linux machines.
The new script, build-dynamic.sh, creates a mold executable with
libmimalloc, libtbb, libstdc++ and libcrypto begin linked statically.
I don't have a concern as to the availability of other libraries
(libc, libm, libz and librt) because they essentially exists on any
system.
This commit ensure that all symbol resolution results are cleared
after LTO, so that the following second symbol resolution will not
be affected by the previous results.
It looks like setting __TBB_DYNAMIC_LOAD_ENABLED to 0 is not enough
to make TBB not to call dlopen(). We need to unset __TBB_WEAK_SYMBOLS_PRESENT
as well.
Fixes https://github.com/rui314/mold/issues/348
When building with SYSTEM_MIMALLOC=1, linking with (assuming
shared) '-lmimalloc' is not enough to override C++ new/delete
with mimalloc versions, and 'mimalloc-new-delete.h' should be
included from one (and the only) translation unit as well.
Signed-off-by: Dmitry Antipov <dantipov@cloudlinux.com>
ELF object files returned by do_lto() may contain unforeseen undefined
symbols, so we can't call that function after the symbol resolution pass
because it can cause undefined symbol errors.
In the previous commit (c325cc039a),
I argued that PC-relative relocations are not representable if they
refer absolute symbols, and I made a change so that such relocations
are handled as errors.
Even though what I did is technically correct, that results in a failure
of an important use case of the weak undefined symbol. Here is why.
If you have an weak undefined symbol `foo`, you would use it as follows:
if (foo)
foo();
If `foo` is defined (i.e. has an address other than 0), `foo` is called.
If `foo` is undefined (i.e. has the address 0), the subsequent CALL
instruction will have an offset from the CALL instruction to address 0.
That displacement is computed at link-time. If the output is position-
independent, the call instruction may not have a correct displacement
from address 0 to the instruction at runtime due to base relocation.
However, that's not a problem in practice, because the function call
is guarded by `if (foo)`, and that will always evaluated to false
if `foo` is undefined. Therefore, the faulty `CALL` instruction will
never be executed.
So, that means we need to relocate PC-relative relocations against
absolute symbols even if doing so results in an incorrect result.
This patch implement that.
PC-relative relocations against absolute symbols are not representable
in position-independent code. In order to support such relocations,
someone has to compute `S + A - P` or subtract `B` as a base relocation,
but such dynamic relocations don't exist.
This is contrary to non-PC-relative relocations against non-absolute
symbols. In this case, we can simply use the base relocation (e.g.
R_X86_64_RELATIVE).
https://github.com/rui314/mold/issues/348
It looks like the option is supported only by gold, and it doesn't
make much sense to me to have this option along with more generic
--warn-textrel. So I want to remove this before the next release.
This patch removes the --shuffle-sections option that takes an
argument as I'm still thinking about a better name for the option.
You can still use `--shuffle-sections` that doesn't take an argument.
If a relocation's r_sym value is 0 (i.e. it refers the undefined symbol
at the beginning of the symbol table), it has to handled as if S were 0.
We used to handle as if S were -1.
In addition to that, even if a relocation needs a dynamic base relocation,
it doesn't mean its expression is always S+A. For example, calling an
absolute address needs a dynamic relocation but its expression is S+A-P.
Fixes https://github.com/rui314/mold/issues/348
This reverts commit ddcb7b4197. `is_dso`
is used by hot functions such as `Symbol::get_addr()`, so we want to
eliminate the cost of virtual function dispatch.
