/ALTERNATENAME is a rarely-used, undocumented command line option that is
needed to link LLD for release build. It seems that the option is for defining
an weak alias; /alternatename:foo=bar defines weak symbol "foo" for "bar".
If "foo" is defined in an input file, it'll be linked normally and the command
line option will have no effect. If it's not defined, "foo" will be handled
as an alias for "bar".
This patch implements the parser for the option. The actual weak alias handling
will be implemented in a separate patch.
llvm-svn: 196743
GroupedSectionsPass was a complicated pass. That pass's job was to reorder
atoms by section name, so that the atoms with the same section prefix will be
emitted consecutively to the executable. The pass added layout edges to atoms,
and let the layout pass to actually reorder them.
This patch simplifies the design by making GroupedSectionPass to directly
reorder atoms, rather than adding layout edges. This resembles ELF's
ArrayOrderPass.
This patch improves the performance of LLD; it used to take 7.1 seconds to
link LLD with LLD on my Macbook Pro, but it now takes 6.1 seconds.
llvm-svn: 196628
Emitting idata atoms to their own section would make debugging easier.
The Windows loader do not really care about whether the DLL import table is
in .rdata or its own .idata section, so there is no change in functionality.
llvm-svn: 196458
This is a patch to let the PECOFF writer to use the information passed
by the parser for /section option. The implementation of /section should
now be complete.
llvm-svn: 195893
/MERGE option is a bit complicated for many reasons. Firstly, it takes both
positive and negative arguments. That means we have to have one of three
distinctive values (set, clear or unchange) for each permission bit. In this
patch we represent the three values using two bitmasks.
Secondly, the permissions specified by the parameter is bitwise or-ed with the
default permissions of a section. There is an exception for that rule; if one
of READ, WRITE or EXECUTE bit is specified, unspecified bits need to be
cleared. (So if you specify only WRITE for example, the resulting section will
not have WRITE nor EXECUTE bits.)
Lastly, multiple /merge options are allowed.
llvm-svn: 195882
Atom ordinals are the indeces in a file. Currently the PECOFF reader assigns
ordinals for each section, so it's (incorrectly) assigning duplicate ordinals.
llvm-svn: 195852
Instead of having multiple SectionChunks for each section (.text, .data,
.rdata and .bss), we could have one chunk writer that can emit any sections.
This patch does that -- removing all section-sepcific chunk writers and
replace them with one "generic" writer.
This change should simplify the code because it eliminates similar-but-
slightly-different classes.
It also fixes an issue in the previous design. Before this patch, we could
emit only limited set of sections (i.e. .text, .data, .rdata and .bss). With
this patch, we can emit any sections.
llvm-svn: 195797
According to the PE/COFF spec, a section with IMAGE_SCN_LNK_INFO should only
appear in an object file, and not allowed in an executable. So I believe
treating it as the same way as IMAGE_SCN_LNK_INFO is the right thing.
llvm-svn: 195692
This patch won't change the output because the layout of linker internal
atoms is forced by layout-{before,after} references. Ordinals of the linker
internal atoms are not currently used. (That's why it's working even if there
are atoms having the same ordinals.)
llvm-svn: 195610
Change the attribute from sectionBasedOnContent to sectionCustomRequired
because its the right attribute for atoms read from COFF files to have.
COFF atoms should basically be emitted to the section having the same name
as input. Permissions/attributes should not affect that.
There's no functionality change because the writer doesn't yet use the
section name. The writer will be modified in a following patch, so that atoms
are written to its customSectionName()'s section.
llvm-svn: 195595
Looks like -L paths are not positional. They need to be added to a list of
search paths and those needs to be searched when lld looks for a library.
llvm-svn: 195594
If /subsystem option is not specified, the linker needs to infer it from the
entry point function. If "main" or "wmain" is defined, it's a console
application. If "WinMain" or "wWinMain" is defined, it's a GUI application.
llvm-svn: 195592
This adds LinkerScript support by creating a type Script which is of type
FileNode in the InputGraph. Once the LinkerScript Parser converts the
LinkerScript into a sequence of command, the commands are handled by the
equivalent LinkerScript node for the current Flavor/Target. For ELF, a
ELFGNULdScript gets created which converts the commands to ELF nodes and ELF
control nodes(ELFGroup for handling Group nodes).
Since the Inputfile type has to be determined in the Driver, the Driver needs
to determine the complete path of the file that needs to be processed by the
Linker. Due to this, few tests have been removed since the Driver uses paths
that doesnot exist.
llvm-svn: 195583
NativeReferenceIvarsV1 cannot handle more than 65535 relocation targets
because its field to point to the target table is of type uint16_t. Because
of that limitation, the LLD couldn't link a file containing more than 65535
relocations. 65535 is not a big number - the LLD couldn't even link itself
with V1.
This patch solves the issue by adding NativeReferenceIvarsV2 support. The
new structure has more bits for the target table, so it can handle a large
number of relocatinos.
V2 structure is larger than V1. In order to prevent file bloating, V2 format
is used only when the resulting file cannot be represented in V1 format. The
writer and the reader support both V1 and V2 formats.
Differential Revision: http://llvm-reviews.chandlerc.com/D2217
llvm-svn: 195270
The maximum number of references the file with NativeReferenceIvarsV1 can
contain is 65534. If a file larger than that is converted to Native format,
the conversion will fail without any error message. This caused a subtle bug
that the LLD would produce a broken executable only when input files contain
too many references.
This issue exists since the RoundTripNativeTest is introduced in r193585. Since
then, it seems that nobody have linked any program having more than 65534
relocations with the LLD. Otherwise we would have found it earlier.
llvm-svn: 194987
This patch does not change the meaning of the program, but if something's wrong
in the linker or the compiler and the control reaches to the gap of imported
function table, it will stop immediately because of the presence of INT3. If
NOP, it'd fall through to the next call instruction, which is usually a
completely foreign function call.
llvm-svn: 194860
The result of sizeof(SymbolTable<ELFT>::SymbolEntry) in DynamicSymbolTable
<ELFT>::write() was different from the same expression in RelocationTable
<ELFT>::write(), although the same template parameters were passed. They were
40 and 32, respectively. As a result, the same vector was treated as a
vector of 40 byte values in some places and a vector of 32 values in other
places. That caused an weird issue, resulting in collapse of the rela.dyn
section.
I suspect that this is a padding size calculation bug in MSVC 2012, but I
may be wrong. Reordering the fields to eliminate padding seems to fix the
issue.
llvm-svn: 194349
This patch adds support for converting normalized mach-o to and from binary
mach-o. It also changes WriterMachO (which previously directly wrote a
mach-o binary given a set of Atoms) to instead do it in two steps. The first
step uses normalizedFromAtoms() to convert Atoms to normalized mach-o, and the
second step uses writeBinary() which to generate the mach-o binary file.
llvm-svn: 194167
These fields are for /align option. Section alignment can be set per-section
basis with /section option too. In order to avoid name conflicts, rename the
existing identifiers to become more specific. No functionality change.
llvm-svn: 194160
We wrapped the linker internal file with a virtual archive file, so that the
linker internal file was linked only when it's actually used. This was to avoid
__ImageBase being included to the resulting executable. __ImageBase used to
occupy four bytes when emitted to executable.
And then it turned out that the implementation of __ImageBase was wrong -- it
shouldn't have been a regular atom but an absolute atom. Absolute atoms point
to some memory location, but they don't occupy disk space themselves. So it
wouldn't increase executable size (except the symbol table.) That means that
it's OK to link the linker internal file unconditionally.
So this patch does that, removing the wrapper archive file. Doing this
simplifies the code.
llvm-svn: 194127
n_desc field in MachO string table was not initialized. On Unix,
test/darwin/hello-world.objtxt did not fail because I think an nlist object
is always allocated to a fresh heap initialized with zeros. On Windows,
uninitialized fields are filled with 0xCC when compiled with /GZ. Because
of that the test was failing on Windows.
llvm-svn: 193909
Bugs that would be caught by this assertion would also be caught by
RoundTripYAMLPass test. We've enabled the pass for PECOFF, so we can remove
this.
llvm-svn: 193886
The data directory in the PE/COFF header consisted of list of data directory
atoms. This patch changes it -- now there's only one data directory entry that
contains former data directories. That's easier to handle in the writer as well
as to write to/read from YAML/Native files. The main purpose of this refactoring
is to enable RoundTrip tests for PE/COFF.
There's no functionality change.
llvm-svn: 193854
This reverts commit r193479.
The atoms are already added to the file, so re-adding them caused the YAML
writer to write the same atoms twice. That made the YAML reader to fail with
"duplicate atom name" error.
This is not the only error we've got for RoundTripYAMLPass for PECOFF, so we
cannot enable the test yet. More fixes will come.
Differential Revision: http://llvm-reviews.chandlerc.com/D2069
llvm-svn: 193762
Enable this for the following flavors
a) core
b) gnu
c) darwin
Its disabled for the flavor PECOFF. Convenient markers are added with FIXME
comments in the Driver that would be removed and code removed from each flavor.
llvm-svn: 193585
__ImageBase is an absolute symbol whose address is the same as the image base
address. What we did before this patch was to create __ImageBase symbol as a
symbol whose *contents* (not location) is the image base address, which is
clearly wrong.
llvm-svn: 193565
On discussing this with Nick, it looks like the StubAtoms
that contain a lazyImmediate reference kind should be null
and the location needs to be fixed up later with some value
that is an offset into the __LINKEDIT segment.
The drawback is that it allows yaml files with references
that expect a target to be considered without one.
This results in bad yaml files that would need to be handled
in the YAML Reader.
Inorder to fix this, the Stub Atoms use a dummy target such
as itself.
llvm-svn: 193476
/merge:<from>=<to> option makes the linker to combine "from" section to "to"
section. This patch is to parse the option. The actual feature will be
implemented in a subsequent patch.
llvm-svn: 193454
Disable tests to be run with REQUIRES: disable. Note disable is not added to the
config by the test runner Mkaefiles, so essentially disables the test.
Code changes would be required to fix these tests :-
test/darwin/hello-world.objtxt
test/elf/check.test
test/elf/phdr.test
test/elf/ppc.test
test/elf/undef-from-main-dso.test
test/elf/X86_64/note-sections-ro_plus_rw.test
test/pecoff/alignment.test
test/pecoff/base-reloc.test
test/pecoff/bss-section.test
test/pecoff/drectve.test
test/pecoff/dynamic.test
test/pecoff/dynamicbase.test
test/pecoff/entry.test
test/pecoff/hello.test
test/pecoff/imagebase.test
test/pecoff/importlib.test
test/pecoff/lib.test
test/pecoff/multi.test
test/pecoff/reloc.test
test/pecoff/weak-external.test
llvm-svn: 193300
This patch won't change LLD's behavior because it's a temporary file and
LLD does not use the file extension to determine file type. But using the
correct file extension is a good thing.
llvm-svn: 193211
We should dead-strip atoms only if they are created for COMDAT symbols. If we
remove non-COMDAT atoms from a binary, it will no longer be guaranteed that
the binary will work correctly.
In COFF, you can manipulate the order of section contents in the resulting
binary by section name. For example, if you have four sections
.data$unique_prefix_{a,b,c,d}, it's guaranteed that the contents of A, B, C,
and D will be consecutive in the resulting .data section in that order.
Thus, you can access B's and C's contents by incrementing a pointer pointing
to A until it reached to D. That's why we cannot dead-strip B or C even if
no one is directly referencing to them.
Some object files in the standard library actually use that technique.
llvm-svn: 193017
INT 3 (machine code 0xCC) will raise an interrupt when executed. That is better
for filling the gap than NOP because we want to stop the execution immediately
when the control reached to non-code address.
llvm-svn: 192945
This change removes code in various places which was setting the File Ordinals.
This is because the file ordinals are assigned by the way files are resolved.
There was no other way than making the getNextFileAndOrdinal be set const and
change the _nextOrdinal to mutable.
There are so many places in code, that you would need to cleanup to make
LinkingContext non-const!
llvm-svn: 192280
This is the first step in how I plan to get mach-o object files support into
lld. We need to be able to test the mach-o Reader and Write on systems without
a mach-o tools. Therefore, we want to support a textual way (YAML) to represent
mach-o files.
MachONormalizedFile.h defines an in-memory abstraction of the content of mach-o
files. The in-memory data structures are always native endianess and always
use 64-bit sizes. That internal data structure can then be converted to or
from three different formats: 1) yaml (text) encoded mach-o, 2) binary mach-o
files, 3) lld Atoms.
This patch defines the internal model and uses YAML I/O to implement the
conversion to and from the model to yaml. The next patch will implement
the conversion from normalized to binary mach-o.
This patch includes unit tests to validate the yaml conversion APIs.
llvm-svn: 192147
Changes :-
a) Functionality in InputGraph to insert Input elements at any position
b) Functionality in the Resolver to use nextFile
c) Move the functionality of assigning file ordinals to InputGraph
d) Changes all inputs to MemoryBuffers
e) Remove LinkerInput, InputFiles, ReaderArchive
llvm-svn: 192081
This will eventually need to be refactored to better handle COPY relocations,
as other relocations can also generate them. I'm not yet sure the exact
circumstances in which they are needed yet.
llvm-svn: 191567
This patch inverts the return value of these functions, so that they return
"true" on success and "false" on failure. The meaning of boolean return value
was mixed in LLD; for example, InputGraph::validate() returns true on success.
With this patch they'll become consistent.
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1748
llvm-svn: 191341
Summary:
This patch changes WriterPECOFF to actually write down the address instead of ignoring it.
Also, it changes the order of adding the BaseReloc chunk as otherwise the address wasn't set yet.
I think a better way of doing it would be to change DataDirectoryAtom to create a Reference
instead of using a number, and to change IdataPass accordingly, but I'm not sure how to do that.
Reviewers: ruiu
Reviewed By: ruiu
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1743
llvm-svn: 191220
Summary: This patch changes WritePECOFF to calculate the value of the SizeOfHeaders PE header field instead of just using 512.
Reviewers: rui314, ruiu
Reviewed By: ruiu
CC: llvm-commits, ruiu
Differential Revision: http://llvm-reviews.chandlerc.com/D1708
llvm-svn: 191212
This adds an option --output-filetype that can be set to either
YAML/Native(case insensitive). The linker would create the outputs
associated with the type specified by the user.
Changes all the tests to use the new option.
llvm-svn: 191183
This also makes it support debugging executables built with lld.
Initial patch done by Bigcheese. This is only a revised patch to
have the functionality in the Writer.
llvm-svn: 191032
Base relocation block should be aligned on a 32-bit boundary. While the PECOFF
spec mentions only aligning the blocks, and not padding them, link.exe seems
to add an extra IMAGE_REL_I386_ABSOLUTE entry (just a zeroed WORD) in order to
pad the blocks.
Patch by Ron Ofir.
llvm-svn: 190951
This sets the sectionChoice property for DefinedAtoms. The output section name
is derived by the property of the atom. This also decreases native file size.
Adds a test.
llvm-svn: 190840
This patch changes lld to go through all sections while calculating the size
for SizeOfCode, SizeOfInitializedData and SizeOfUninitializedData fields in the
PE header, instead of using only a small set of hard-coded sections.
This only really changes SizeOfInitializedData which didn't include .reloc
section before this patch.
Patch by Ron Ofir.
llvm-svn: 190799
This patch sets the IMAGE_SCN_MEM_DISCARDABLE characteristic to the base
relocations section in order to match MS PECOFF specification.
Patch by Ron Ofir.
llvm-svn: 190798
There was a bug that if a section has an alignment requirement and there are
multiple symbols at offset 0 in the section, only the last atom at offset 0
would be aligned properly. That bug would move only the last symbol to an
alignment boundary, leaving other symbols unaligned, although they should be at
the same location. That caused a mysterious SEGV error of the resultant
executable.
With this patch, we manage all symbols at the same location properly, rather
than keeping the last one.
llvm-svn: 190724
Alignment(1) does not mean that the atom should be aligned on a 1 byte
boundary but on a 2^1 boundary. So, atoms without any specific alignment
requirements should have Alignment(0).
llvm-svn: 190723
This handles multiple weak symbols which appear back to back. This fix is needed
which otherwise will lead to symbols getting initialized to arbitrary values.
There was a constructor/destructor test that really triggered this to be fixed
on X86_64.
Adds a test.
llvm-svn: 190658
So that we can determine what the target architecture is. Adding this
field does not mean that we are going to support non-i386 architectures
soon; there are many things to do to support them, and I'm focusing on
i386 now. But this is the first step toward multi architecture support.
llvm-svn: 190627
In COFF, an undefined symbol can have up to one alternative name. If a symbol
is resolved by its regular name, then it's linked normally. If a symbol is not
found in any input files, all references to the regular name are resolved using
the alternative name. If the alternative name is not found, it's a link error.
This mechanism is called "weak externals".
To support this mechanism, I added a new member function fallback() to undefined
atom. If an undefined atom has the second name, fallback() returns a new undefined
atom that should be used instead of the original one to resolve undefines. If it
does not have the second name, the function returns nullptr.
Differential Revision: http://llvm-reviews.chandlerc.com/D1550
llvm-svn: 190625
Mangling scheme varies on platform, and prepending an underscore is valid only
on 32-bit x86. Added a method to mangle name to PECOFFLinkingContext and use
it to avoid hard coding mangled names.
llvm-svn: 190585
attribute in LinkerInput to isWholeArchive and use that for deciding
whether library archives should be expanded. Implement the -all_load
option of the Darwin linker using this flag and drop the support for it
in GNU mode.
llvm-svn: 190275
Rui Ueyama