loadFile could load mulitple files just because yaml has a feature for
putting multiple documents in one file.
Designing a linker around what yaml can do seems like a bad idea to
me. This patch changes it to read a single file.
There are further improvements to be done to the api and they
will follow shortly.
llvm-svn: 235724
The Native file format was designed to be the fastest on-memory or
on-disk file format for object files. The problem is that no one
is working on that. No LLVM tools can produce object files in
the Native, thus the feature of supporting the format is useless
in the linker.
This patch removes the Native file support. We can add it back
if we really want it in future.
llvm-svn: 234641
atom_collection is basically a wrapper for std::vector. The class
provides begin and end member functions, so that it "hides" the
other member functions provided by std::vector. However, you can
still directly access _atoms member since the member is not
protected.
We cannot simply make the member private because we need that member
when we are constructing atom vectors.
This patch splits atom_collection into two types: std::vector<Atom *>
and AtomRange. When we are constructing atom vectors, we use the
former class. We return instances of the latter class from File
objects so that callers cannot add or remove atoms from the lists.
std::vector<Atom *> is automatically converted to AtomRange.
llvm-svn: 234450
canParse took three parameters -- file magic, filename extension and
memory buffer. All but YAMLReader ignored the second parameter.
This patch removes the parameter.
llvm-svn: 234080
This patch defines implicit conversion between integers and PowerOf2
instances, so uses of the classes is now implicit and look like
regular integers. Now we are ready to remove the scaffolding.
llvm-svn: 233245
I knew I cut corners when I wrote this. Turned out that it is
actually slow when a file being read has many symbols. This patch
is to stop doing linear search and instead do map lookup.
llvm-svn: 232436
All readers except PE/COFF reader create layout-after edges to preserve
the original symbol order. PE/COFF uses layout-before edges as primary
edges for no reason.
This patch makes PE/COFF reader to create layout-after edges.
Resolver is updated to recognize reverse edges of layout-after edges
in the garbage collection pass.
Now we can retire layout-before edges. I don't do that in this patch
because if I do, I would have updated many tests to replace all
occurrrences of "layout-before" with "layout-after". So that's a TODO.
llvm-svn: 231615
This patch reverts r231545 "PECOFF: Do not add extraneous symbols
to the dead strip root." CrWinClangLLD buildbot is currently broken.
Since I can't reproduce the issue locally, I'm reverting the most
relevant change.
llvm-svn: 231582
Previously we added all undefined symbols found in object files to
the dead strip root. This patch makes the linker to stop doing that.
Undefined symbols would be resolved anyway, so this patch doesn't
change the linker behavior. It should slightly improve performance
but it's really marginal. This is a cleanup.
llvm-svn: 231545
The last use of layout-after edge for PE/COFF was removed in r231290.
Now layout-after edges do nothing. We can stop adding them to the graph.
No functionality change intended.
llvm-svn: 231301
Merge::mergeByLargestSection is half-baked since it's defined
in terms of section size, there's no way to get the section size
of an atom.
Currently we work around the issue by traversing the layout edges
to both directions and calculate the sum of all atoms reachable.
I wrote that code but I knew it's hacky. It's even not guaranteed
to work. If you add layout edges before the core linking, it
miscalculates a size.
Also it's of course slow. It's basically a linked list traversal.
In this patch I added DefinedAtom::sectionSize so that we can use
that for mergeByLargestSection. I'm not very happy to add a new
field to DefinedAtom base class, but I think it's legitimate since
mergeByLargestSection is defined for section size, and the section
size is currently just missing.
http://reviews.llvm.org/D7966
llvm-svn: 231290
This reverts commit r230086. I added a lock to guard FileCOFF::doParse(),
which killed parallel file parsing. Now the buildbots got back to green,
I believe the threading issue was resolved, so it's time to remove the
guard to see if it works with the buildbots.
llvm-svn: 230886
In doParse, we shouldn't do anything that has side effects. That function may be
called speculatively and possibly in parallel.
We called WinLinkDriver::parse from doParse to parse a command line in a .drectve
section. The parse function updates a linking context object, so it has many side
effects. It was not safe to call that function from doParse. beforeLink is a
function for a File object to do something that has side effects. Moving a call
of WinLinkDriver::parse to there.
llvm-svn: 230791
This reverts commit r230732.
sectionSize() in lib/Core/SymbolTable.cpp still depends on the layout-
after edges, so we couldn't remove them yet.
llvm-svn: 230734
Previously we needed to create atoms as a doubly-linked link, but it's
no longer needed. Also we don't use layout-after edges in PE/COFF.
Creating such edges is just waste.
llvm-svn: 230732
Previously we have a string -> string map to keep the weak alias
symbol mapping. Naturally we can't define more than one weak alias
with that data structure.
This patch is to allow multiple aliases for the same symbol by
changing the map type to string -> set of string map.
llvm-svn: 230702
Looks like there's a threading issue in the COFF reader which makes
buildbot unstable. Probability of crash varies depending on the number
of input. If we are linking a big executalbe, LLD almost always crash.
This patch temporarily adds a lock to guard the reader so that LLD
doesn't crash. I'll investigate and fix the issue as soon as possible
because this patch has negative performance impact.
llvm-svn: 230086
Weak aliases defined using /alternatename command line option were getting
wrong RVAs in the final output because of wrong atom ordinal. Alias atoms
were assigned large ordinals than any other regular atoms because they were
instantiated after other atoms and just got new (larger) ordinals.
Atoms are sorted by its file and atom ordinals in the order pass. Alias
atoms were located after all other atoms in the same file.
An alias atom's ordinal needs to be smaller than its alias target but larger
than the atom appeared before the target -- so that the alias is located
between the two. Since an alias has no size, the alias target will be located
at the same location as the alias.
In this patch, I made a gap between two regular atoms so that we can put
aliases after instantiating them (without re-numbering existing atoms).
llvm-svn: 229762
atomContent's memory is freed at the end of the stack frame,
but it is referenced by the atom pushed into _definedAtoms.
Differential Revision: http://reviews.llvm.org/D7732
llvm-svn: 229749
* Removed cyclic dependency between lldPECOFF and lldDriver
* Added missing dependencies in unit tests
Differential Revision: http://reviews.llvm.org/D7185
llvm-svn: 227134
Before this patch there was a cyclic dependency between lldCore and
lldReaderWriter. Only lldConfig could be built as a shared library.
* Moved Reader and Writer base classes into lldCore.
* The following shared libraries can now be built:
lldCore
lldYAML
lldNative
lldPasses
lldReaderWriter
Differential Revision: http://reviews.llvm.org/D7105
From: Greg Fitzgerald <garious@gmail.com>
llvm-svn: 226732
LLD parses archive file index table only at first. When it finds a symbol
it is looking for is defined in a member file in an archive file, it actually
reads the member from the archive file. That's done in the core linker.
That's a single-thread process since the core linker is single threaded.
If your command line contains a few object files and a lot of archive files
(which is quite often the case), LLD hardly utilizes hardware parallelism.
This patch improves parallelism by speculatively instantiating archive
file members. At the beginning of the core linking, we first create a map
containing all symbols defined in all members, and each time we find a
new undefined symbol, we instantiate a member file containing the
symbol (if such file exists). File instantiation is side effect free, so this
should not affect correctness.
This is a quick benchmark result. Time to link self-link LLD executable:
Linux 9.78s -> 8.50s (0.86x)
Windows 6.18s -> 4.51s (0.73x)
http://reviews.llvm.org/D7015
llvm-svn: 226336
The original commit had an issue with Mac OS dylib files. It didn't
handle fat binary dylib files correctly. This patch includes a fix.
A test for that case has already been committed in r225764.
llvm-svn: 226123
r225764 broke a basic functionality on Mac OS. This change reverts
r225764, r225766, r225767, r225769, r225814, r225816, r225829, and r225832.
llvm-svn: 225859
This teaches lld about the ARM NT object types. Add a trivial test to ensure
that it can handle ARM NT object file inputs. It is still unable to perform the
necessary relocations for ARM NT, but this allows the linker to at least read
the objects.
llvm-svn: 225052
The documentation of parseFile() said that "the resulting File
object may take ownership of the MemoryBuffer." So, whether or not
the ownership of a MemoryBuffer would be taken was not clear.
A FileNode (a subclass of InputElement, which is being deprecated)
keeps the ownership if a File doesn't take it.
This patch makes File always take the ownership of a buffer.
Buffers lifespan is not always the same as File instances.
Files are able to deallocate buffers after parsing the contents.
llvm-svn: 224113
This is a second patch for InputGraph cleanup.
Sorry about the size of the patch, but what I did in this
patch is basically moving code from constructor to a new
method, parse(), so the amount of new code is small.
This has no change in functionality.
We've discussed the issue that we have too many classes
to represent a concept of "file". We have File subclasses
that represent files read from disk. In addition to that,
we have bunch of InputElement subclasses (that are part
of InputGraph) that represent command line arguments for
input file names. InputElement is a wrapper for File.
InputElement has parseFile method. The method instantiates
a File. The File's constructor reads a file from disk and
parses that.
Because parseFile method is called from multiple worker
threads, file parsing is processed in parallel. In other
words, one reason why we needed the wrapper classes is
because a File would start reading a file as soon as it
is instantiated.
So, the reason why we have too many classes here is at
least partly because of the design flaw of File class.
Just like threads in a good threading library, we need
to separate instantiation from "start" method, so that
we can instantiate File objects when we need them (which
should be very fast because it involves only one mmap()
and no real file IO) and use them directly instead of
the wrapper classes. Later, we call parse() on each
file in parallel to let them do actual file IO.
In this design, we can eliminate a reason to have the
wrapper classes.
In order to minimize the size of the patch, I didn't go so
far as to replace the wrapper classes with File classes.
The wrapper classes are still there.
In this patch, we call parse() immediately after
instantiating a File, so this really has no change in
functionality. Eventually the call of parse() should be
moved to Driver::link(). That'll be done in another patch.
llvm-svn: 224102
LLD skipped COMDAT section symbols when reading them because
I thought we don't want to have symbols with the same name.
But they are actually needed because relocations may refer to
the section symbols. So we shoulnd't skip them.
llvm-svn: 221329
Teach the reader about ARM NT relocation types. Although the writer cannot yet
perform the actual application of these relocations, the reader can at least now
identify the relocation types.
llvm-svn: 219178
Previously, we would not check the target machine type and the module (object)
machine type. Add a check to ensure that we do not attempt to use an object
file with a different target architecture.
This change identified a couple of tests which were incorrectly mixing up
architecture types, using x86 input for a x64 target. Adjust the tests
appropriately. The renaming of the input and the architectures covers the
changes to the existing tests.
One significant change to the existing tests is that the newly added test input
for x64 uses the correct user label prefix for X64.
llvm-svn: 219093
Atoms are ordered in the output file by ordinal. File has file ordinal,
and atom has atom ordinal which is unique within the file.
No two atoms should have the same combination of ordinals.
However that contract was not satisifed for alias atoms. Alias atom
is defined by /alternatename:sym1=sym2. In this case sym1 is defined
as an alias for sym2. sym1 always got ordinal 0.
As a result LLD failed with an assertion failure.
This patch assigns ordinal to alias atoms.
llvm-svn: 218158
Rather than saving whether we are targeting 64-bit x86 (x86_64), simply convert
the single use of that information to the actual relocation type. This will
permit the selection of non-x86 relocation types (e.g. for WoA support).
Inline the access of the machine type field as it is relatively cheap (a couple
of pointer dereferences) rather than storing the relocation type as a member
variable.
llvm-svn: 218104
Rafael Espindola