For ARM thunks, the `movt` half of the relocation was using an incorrect
offset (it was off by 4 bytes). The original intent seems to have been
for the offset to have been relative to the current instruction, in
which case the difference of 4 makes sense. As the code stands, however,
the offset is always calculated relative to the start of the thunk
(`P`), and so the `movw` and `movt` halves should use the same offset.
This requires a very particular offset between the thunk and its target
to be triggered, and it results in the `movt` half of the relocation
being off-by-one.
The tests here use ARM-Thumb interworking thunks, since those are the
only ARM thunks currently implemented. I actually encountered this with
a range extension thunk (having Peter's patches cherry-picked locally),
but the underlying issue is identical.
Differential Revision: https://reviews.llvm.org/D38112
llvm-svn: 313915
This patch goes back to considering ForceAbsolute in moveAbsRight, but
only if the second argument is not already absolute.
With this we can handle "foo + ABSOLUTE(foo)" and "ABSOLUTE(foo) + foo".
llvm-svn: 313800
The idea of this function is to simplify the implementation of binary
operators like add.
A value might be absolute because of an ABSOLUTE expression, but it
still depends on the value of a section and we might not be able to
evaluate it early. We should keep such values on the LHS, so that we
can delay the evaluation.
We can now handle both "1 + ABSOLUTE(foo)" and "ABSOLUTE(foo) + 1".
llvm-svn: 313794
The previous logic was to try to detect if a linker script defined _gp
by checking !ElfSym::MipsGp->Value. That doesn't work in all cases as
the assigned value can be 0.
We now just always defined it Writer.cpp and always overwrite it
afterwards if needed.
llvm-svn: 313788
Normally to find the offset of a value in a section, we have to
compute the value since the alignment is defined on the final address.
If the alignment is trivial, we can skip the value computation. This
allows us to know the offset even in cases where we cannot yet know
the value.
llvm-svn: 313777
We try to evaluate expressions early when possible, but it is not
possible to evaluate them early if they are based on a section.
Before we would get this wrong on ABSOLUTE expressions.
llvm-svn: 313764
Its a PR34648 which was a segfault that happened because
we stored pointers to elements in DenseMap.
When DenseMap grows such pointers are invalidated.
Solution implemented is to keep elements by pointer
and not by value.
Differential revision: https://reviews.llvm.org/D38034
llvm-svn: 313741
EhSectionPiece used to have a pointer to a section, but that pointer was
mostly redundant because we almost always know what the section is without
using that pointer. This patch removes the pointer from the struct.
This patch also use uint32_t/int32_t instead of size_t to represent
offsets that are hardly be larger than 4 GiB. At the moment, I think it is
OK even if we cannot handle .eh_frame sections larger than 4 GiB.
Differential Revision: https://reviews.llvm.org/D38012
llvm-svn: 313697
CieRecord is a struct containing a CIE and FDEs, but oftentimes the
struct itself is named `Cie` which caused some confusion. This patch
renames them `CieRecords` or `Rec`.
llvm-svn: 313681
Given a linker script that ends in
.some_sec { ...} ;
__stack_start = .;
. = . + 0x2000;
__stack_end = .;
lld would put orphan sections like .comment before __stack_end,
corrupting the intended meaning.
The reason we don't normally move orphans past assignments to . is to
avoid breaking
rx_sec : { *(rx_sec) }
. = ALIGN(0x1000);
/* The RW PT_LOAD starts here*/
but in this case, there is nothing after and it seems safer to put the
orphan section last. This seems to match bfd's behavior and is
convenient for writing linker scripts that care about the layout of
SHF_ALLOC sections, but not of any non SHF_ALLOC sections.
llvm-svn: 313646
This is PR34506.
Imagine we have 2 sections the same name but different COMDAT groups:
.section .foo,"axG",@progbits,bar,comdat
.section .foo,"axG",@progbits,zed,comdat
When linking relocatable we do not merge SHT_GROUP sections. But still would merge
both input sections .foo into single output section .foo.
As a result we will have 2 different SHT_GROUPs containing the same section, what
is wrong.
Patch fixes the issue, preventing merging SHF_GROUP sections with any others.
Differential revision: https://reviews.llvm.org/D37574
llvm-svn: 313621
We crashed when --emit-relocs was used
and relocated section was collected by GC.
Differential revision: https://reviews.llvm.org/D37561
llvm-svn: 313620
This patch removes lot of static Instances arrays from different input file
classes and introduces global arrays for access instead. Similar to arrays we
have for InputSections/OutputSectionCommands.
It allows to iterate over input files in a non-templated code.
Differential revision: https://reviews.llvm.org/D35987
llvm-svn: 313619
EhSectionPiece inherited from SectionPiece, but we did not actually use
EhSectionPiece objects as SectionPiece ojbects. They were handled as
distinct types. So it didn't make much sense to use inheritance.
llvm-svn: 313587
"Repl" member is guranteed to have a non-null pointer. If an input
section is not merged by ICF, "Repl" points to "this". Otherwise, it
points to some other section. It must not be NULL.
llvm-svn: 313556
This is not really OK in C++11, and GCc triggers a warning.
We can switch back to default arguments when C++14 will be the
minimum version of the standard supported, see:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#974
Ack'ed by Rafael.
llvm-svn: 313550
Does not seem we need to set SectionIndex here.
It is set in finalizeSections() later.
Differential revision: https://reviews.llvm.org/D37815
llvm-svn: 313522
This fixes pr34301.
As the bug points out, we want to keep some relocations with undefined
weak symbols. This means that we cannot always claim that these
symbols are not preemptible as we do now.
Unfortunately, we cannot also just always claim that they are
preemptible. Doing so would, for example, cause us to try to create a
plt entry when we don't even have a dynamic symbol table.
What almost works is to say that weak undefined symbols are
preemptible if and only if we have a dynamic symbol table. Almost
because we don't want to fail the build trying to create a copy
relocation to a weak undefined.
llvm-svn: 313372
Patch removes one of OutputSectionFactory::addInputSec methods.
That allows to simplify reporting of discarded sections and
should help to D37561.
Differential revision: https://reviews.llvm.org/D37735
llvm-svn: 313361
_gp points to a position in the file, so it is not really absolute. It
is also simpler to not force it to be absolute, so if there is no
strong ABI requirement we should not do it.
llvm-svn: 313333
There is no need to scan over all input sections for relocatable output.
As we do not process or scan relocations anyways.
Patch moves check for Config->Relocatable out to avoid that and also removes
excessive check for isa<EhInputSection> from first for loop.
It is excessive because we handle all of them in a second for loop below.
That all allowed to simplify code.
Differential revision: https://reviews.llvm.org/D37746
llvm-svn: 313127
This should fix the lto bootstrap.
It is somewhat hard to remember about lazy symbols deep down in the
link. It might be worth it replacing them with undefined symbols once
we are done adding files.
llvm-svn: 313103
https://reviews.llvm.org/rL312796 meant that references to garbage collected common symbols would cause a segfault.
This change fixes the behaviour for references to stripped common symbols.
Differential Revision: https://reviews.llvm.org/D37718
llvm-svn: 313086
The patch implements initial support of microMIPS code linking:
- Handle microMIPS specific relocations.
- Emit both R1-R5 and R6 microMIPS PLT records.
For now linking mixed set of regular and microMIPS object files is not
supported. Also the patch does not handle (setup and clear) the
least-significant bit of an address which is utilized as the ISA mode
bit and allows to make jump between regular and microMIPS code without
any thunks.
Differential revision: https://reviews.llvm.org/D37335
llvm-svn: 313028
Replace OutputSection *Cmd to OutputSection *OS. The Commands vector was
moved to OutputSection but the names of the variables were not. This patch
changes the names to match.
Differential Revision: https://reviews.llvm.org/D37627
llvm-svn: 313015
When given
foobar = ALIGN(., 0x100);
my expectation from what the manual says is that the final address of
foobar will be aligned. It seems that bfd aligns the offset in the
section, which causes some odd results if the section is not 0x100
aligned. Gold aligns the address.
This changes lld to align the final address.
llvm-svn: 312979
When building COFF programs many targets such as mingw prefer
to have a gnu ld frontend. Rather then having a fully fledged
standalone driver we wrap a shim around the LINK driver.
Extra tests were provided by mstorsjo
Reviewers: mstorsjo, ruiu
Differential Revision: https://reviews.llvm.org/D33880
llvm-svn: 312926
Rafael Espindola