Summary:
This will allow using the functionality from other linkers. It is also
a prerequisite for sharing the error logging code.
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: emaste, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D38822
llvm-svn: 315725
Relocations.cpp is still head-scratching. Even though relocations are
processed by multiple functions, the functions are effectively one
gigantic function with lots of local and global shared states, because
they are really tightly coupled. It is really hard to predict whether
a change to a function will or will not affect other functions behaviors.
What I'm trying to do is to rewrite the code without breaking the
existing tests so that the code can tolerate a more aggressive
refactoring (i.e. splitting it to logically separated steps).
llvm-svn: 315673
This is not a mechanical transformation. Even though I believe this
patch is correct, I'm not 100% sure if lld with this patch behaves
exactly the same way as before on all edge cases. At least all tests
still pass.
I'm submitting this patch because it took almost a day to understand
this function, and I don't want to lose it.
llvm-svn: 315658
This paves the way for other projects which might /use/ clang or
lld but not necessarily need to the full set of functionality
available to clang and lld tests to be able to have a basic set
of substitutions that allow a project to run the clang or lld
executables.
llvm-svn: 315627
This patch merges computeAddend and computeMipsAddend.
Getting an addend for a relocation is usually pretty easy:
it is either in the r_addend field (if RELA) or in a target
section (if REL).
However, MIPS has many special rules that are different from
other ELF ABIs. I don't think there were technical reasons to
be different, but the reality is that they are different.
It is unfortunate that we had to pass many parameters to
computeAddend, but it seems unavoidable because of MIPS.
llvm-svn: 315617
This is an attempt to make lld's relocation handler code understandable.
Since I don't fully understand what exactly this function does for all
possible cases (I believe no one can), I'm not really sure if this patch
is NFC, but at least no functionality change intended. All tests still pass.
llvm-svn: 315612
It doesn't make sense to link from an alloc section to a non alloc
one as we were doing.
This matches the behavior of both gold and bfd.
llvm-svn: 315584
Previously we did not support following:
foo = ~0xFF;
and had to add space before numeric value:
foo = ~ 0xFF
That was constistent with ld.bfd < 2.30, which shows:
script.txt:3: undefined symbol `~2' referenced in expression,
but inconsistent with gold.
It was fixed for ld.bfd 2.30 as well:
https://sourceware.org/bugzilla/show_bug.cgi?id=22267
Differential revision: https://reviews.llvm.org/D36508
llvm-svn: 315569
GNU ld automatically exports all symbols if no symbols have
been chosen to export via either def files or dllexport attributes.
The same behaviour can also be enabled via the GNU ld option
--export-all-symbols, in case some symbols are marked for export
via a def file or dllexport attribute.
The list of excluded symbols is from GNU ld, minus the
cygwin specific symbols.
Also add support for outputting the actual list of exported
symbols in a def file, as in the GNU ld option --output-def.
These options in GNU ld are documented in
https://sourceware.org/binutils/docs/ld/WIN32.html.
This currently exports all symbols from object files pulled in
from libmingw32 and libmingwex and other static libraries
that are linked in.
Differential Revision: https://reviews.llvm.org/D38760
llvm-svn: 315562
This is implemented in the same way as the other ADDR32NB relocations
for ARM and X64.
Differential Revision: https://reviews.llvm.org/D38815
llvm-svn: 315561
A section was passed to getRelExpr just to create an error message.
But if there's an invalid relocation, we would eventually report it
in relocateOne. So we don't have to pass a section to getRelExpr.
llvm-svn: 315552
We were using uint32_t as the type of relocation kind. It has a
readability issue because what Type really means in `uint32_t Type`
is not obvious. It could be a section type, a symbol type or a
relocation type.
Since we do not do any arithemetic operations on relocation types
(e.g. adding one to R_X86_64_PC32 doesn't make sense), it would be
more natural if they are represented as enums. Unfortunately, that
is not doable because relocation type definitions are spread into
multiple header files.
So I decided to use typedef. This still should be better than the
plain uint32_t because the intended type is now obvious.
llvm-svn: 315525
This patch doesn't change the behavior of the program because it
would eventually return None at end of the function. But it is
better to return None early if we know it will eventually happen.
llvm-svn: 315495
This is PR34546.
Currently LLD creates output sections even if it has no input sections,
but its command contains an assignment.
Committed code just assigns the same flag that was used in previous
live section.
That does not work sometimes. For example if we have following script:
.ARM.exidx : { *(.ARM.exidx*) }
.foo : { _foo = 0; } }
Then first section has SHF_LINK_ORDER flag. But section foo should not.
That was a reason of crash in OutputSection::finalize(). LLD tried to calculate
Link value, calling front() on empty input sections list.
We should only keep access flags and omit all others when creating such sections.
Patch fixes the crash observed.
Differential revision: https://reviews.llvm.org/D37736
llvm-svn: 315441
Usually, a function that does symbol lookup takes symbol name as
its first argument. Also, if a function takes a source location hint,
it is usually the last parameter. So the previous parameter order
was counter-intuitive.
llvm-svn: 315433
Because of r314495, DefinedCommon symbols cannot reach to
getSymbolValue function. When they reach the fucntion, they have
already been converted to DefinedRegular symbols.
llvm-svn: 315432
We used CurAddressState to capture a dynamic context just like
we use lambdas to capture static contexts. So, CurAddressState
is used everywhere in LinkerScript.cpp. It is worth a shorter
name.
llvm-svn: 315418
"Commands" was ambiguous because in the linker script, everything is
a command. We used to handle only SECTIONS commands, and at the time,
it might make sense to call them the commands, but it is no longer
the case. We handle not only SECTIONS but also MEMORY, PHDRS, VERSION,
etc., and they are all commands.
llvm-svn: 315409
HasSections is true if there is at least one SECTIONS linker
script command, and it is not directly related to whether we have
section objects or not. So I think the new name is better.
llvm-svn: 315405
ScriptConfiguration was a class to contain parsed results of
linker scripts. LinkerScript is a class to interpret it.
That ditinction was needed because we haven't instantiated
LinkerScript early (because, IIRC, LinkerScript class was a
ELFT template function). So, when we parse linker scripts,
we couldn't directly store the result to a LinkerScript instance.
Now, that limitation is gone. We instantiate LinkerScript
at the very beginning of our main function. We can directly
store parse results to a LinkerScript instance.
llvm-svn: 315403
Because addRegular's functionality is tightly coupled with
addSymbol, and the former is called only once, it makes sense
to merge the two functions. This patch also adds comments.
llvm-svn: 315401
Fixes PR34306.
This is because it usually results in more compact code, and because
there are also known code generation bugs when using the PIC model
(see bug).
Based on a patch by Carlo Kok.
Differential Revision: https://reviews.llvm.org/D38769
llvm-svn: 315400
The condition whether a section is alive or not by default
is becoming increasingly complex, so the decision of garbage
collection is spreading over InputSection.h and MarkLive.cpp,
which is not a good state.
This moves the code to MarkLive.cpp, to keep the file the central
place to make decisions about garbage collection.
llvm-svn: 315384
We just don't need one with the current setup.
We only error on undefined references that are used by some
relocation.
If we managed to relax all uses of __tls_get_addr, no relocation uses
it and we don't produce an error.
This is less code and fixes the case were we fail to relax. Before we
would produce a broken output, but now we produce an error.
llvm-svn: 315334
When parsing linker scripts, LLD previously started with a '.' value of 0,
regardless of the internal default image base for the target, and regardless of
switches such as --image-base. It seems reasonable to use a different image base
value when using linker scripts and --image-base is specified, since otherwise the
switch has no effect. This change does this, as well as removing unnecessary
initialisation of Dot where it is not used.
The default image base should not be used when processing linker
scripts, because this will change the behaviour for existing linker script users,
and potentially result in invalid output being produced, as a subsequent assignment
to Dot could move the location counter backwards. Instead, we maintain the existing
behaviour of starting from 0 if --image-base is not specified.
Reviewers: ruiu
Differential Revision: https://reviews.llvm.org/D38360
llvm-svn: 315293
When findOrphanPos does the reverse search to find the OutputSection
preceding the orphan's insertion point, look for a live OutputSection
and ignore "dead" OutputSection's. This matches the behaviour of the
forward search performed earlier in this function.
Added test which without the above fix fails as a result of an orphan
executable section being incorrectly placed in a non-executable segment.
Differential Review: https://reviews.llvm.org/D38690
llvm-svn: 315292
Previously, when we added an input section to an output section, we
called `OutputSectionFactory::addInputSec`. This isn't a good design
because, a factory class is intended to create a new object and
return it, but in this use case, it will never create a new object.
This patch fixes the design flaw.
llvm-svn: 315138
Rafael Espindola