Commit Graph

896 Commits

Author SHA1 Message Date
Chandler Carruth 96f02da75a The LLD tests require 'llvm-nm' to run as well, ensure that this is
built before running the test suite.

llvm-svn: 231770
2015-03-10 08:08:58 +00:00
Chandler Carruth 8300c76b15 Don't write output to 'a.out', write it to a temporary file. This fixes
the test when run frem a read-only checkout of the source tree.

llvm-svn: 231769
2015-03-10 08:06:49 +00:00
Simon Atanasyan d3388cc9b6 [Mips] Implement R_MIPS_SUB relocation handling
llvm-svn: 231643
2015-03-09 10:53:50 +00:00
Simon Atanasyan 1397f520d4 [Mips] Implement R_MIPS_64 relocation handling
llvm-svn: 231642
2015-03-09 10:53:41 +00:00
Simon Atanasyan e604e8f970 [Mips] Show error message and stop linking in case of cross mode jump errors
llvm-svn: 231640
2015-03-09 10:53:24 +00:00
Simon Atanasyan 9af798f5e4 [Mips] Fix incorrect handling of cross mode jumps
We should not take in account a type of "source" symbol. Cross mode jump
adjustment is requred when target symbol and relocation belong to
different (regular/microMIPS) instruction sets.

llvm-svn: 231639
2015-03-09 10:53:15 +00:00
Rui Ueyama 5768e9fde9 Test: Use layout-after instead of layout-before.
Update the tests so that they use layout-after instead of layout-before.
In all other places, we use layout-afters as primary edges.

llvm-svn: 231627
2015-03-09 04:00:29 +00:00
Rui Ueyama d18a97cb7a PECOFF: Create layout-afters instead of layout-befores.
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
2015-03-09 00:06:07 +00:00
Rui Ueyama 47d101e613 PECOFF: Fix off-by-one error.
We accidentally skipped the last base relocation entry for each block.

llvm-svn: 231586
2015-03-08 03:23:43 +00:00
Rui Ueyama 13003d7774 Core: Make the resolver faster.
In the resolver, we maintain a list of undefined symbols, and when we
visit an archive file, we check that file if undefined symbols can be
resolved using files in the archive. The archive file class provides
find() function to lookup a symbol.

Previously, we call find() for each undefined symbols. Archive files
may be visited multiple times if they are in a --start-group and
--end-group. If we visit a file M times and if we have N undefined
symbols, find() is called M*N times. I found that that is one of the
most significant bottlenecks in LLD when linking a large executable.

find() is not a very cheap operation because it looks up a hash table
for a given string. And a string, or a symbol name, can be pretty long
if you are dealing with C++ symbols.

We can eliminate the bottleneck.

Calling find() with the same symbol multiple times is a waste. If a
result of looking up a symbol is "not found", it stays "not found"
forever because the symbol simply doesn't exist in the archive.
Thus, we should call find() only for newly-added undefined symbols.
This optimization makes O(M*N) O(N).

In this patch, all undefined symbols are added to a vector. For each
archive/shared library file, we maintain a start position P. All
symbols [0, P) are already searched. [P, end of the vector) are not
searched yet. For each file, we scan the vector only once.

This patch changes the order in which undefined symbols are looked for.
Previously, we iterated over the result of _symbolTable.undefines().
Now we iterate over the new vector. This is a benign change but caused
differences in output if remaining undefines exist. This is why some
tests are updated.

The performance improvement of this patch seems sometimes significant.
Previously, linking chrome.dll on my workstation (Xeon 2.4GHz 8 cores)
took about 70 seconds. Now it takes (only?) 30 seconds!

http://reviews.llvm.org/D8091

llvm-svn: 231434
2015-03-06 00:28:41 +00:00
Rui Ueyama 77a4da1991 Define DefinedAtom::sectionSize.
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
2015-03-04 21:40:46 +00:00
Davide Italiano 7a89462158 [ELF] Implement R_X86_64_PC16 relocation.
Yet another chapter in the story. We're getting there, finally.
Note for the future: the tests for relocation have a lot of duplication
and probably can be unified in a single file. Let's reevaluate this once
the support will be complete (hopefully, soon).

llvm-svn: 231057
2015-03-03 07:38:20 +00:00
Rui Ueyama c817fd2273 Call File::beforeLink hook even if the file is in an archive.
Previously we didn't call the hook on a file in an archive, which
let the PE/COFF port fail to link files in archives. It was a
simple mistake. Added a call to the hook and also added a test to
catch that error.

const_cast is an unfortunate hack. Files in the resolver are usually
const, but they are not actually const objects, since they are
mutated if either a file is taken from an archive (an archive file
does never return the same file twice) or the beforeLink hook is
called. Maybe we should just remove const from there -- because they
are not const.

llvm-svn: 230808
2015-02-27 23:15:11 +00:00
Rui Ueyama 5b3d935fce Update comments, fix typos.
llvm-svn: 230729
2015-02-27 04:23:21 +00:00
Simon Atanasyan 82ae48eeb5 [Driver] Use paths explicitly provided by the -L option before default paths
User should be able to override default search paths using the -L
option.

http://reviews.llvm.org/D7902

llvm-svn: 230679
2015-02-26 20:09:50 +00:00
Davide Italiano a82ae9146e [Core] Do not reclaim absolute atoms in resolver.
This fixes a linker crash (found out while testing --gc-sections,
testcase provided by Rafael Avila de Espindola).
While this behaviour was found while testing ELF, it' not necessarily
ELF specific and this change is (apparently) harmless on all the
other drivers.

Differential Revision:  D7823
Reviewed by:    ruiu

llvm-svn: 230614
2015-02-26 05:39:57 +00:00
Michael J. Spencer 09358d247a Add Example Sub Target.
llvm-svn: 230594
2015-02-26 00:48:10 +00:00
Davide Italiano 9793956644 [ELF][X86_64] Handle R_X86_64_PC64 relocation
Differential Revision:	D7820
Reviewed by:	shankarke, ruiu

llvm-svn: 230465
2015-02-25 05:56:05 +00:00
Shankar Easwaran 9e07346679 [ELF] Add section group/COMDAT support.
SHF_GROUP: Group Member Sections
----------------------------------
A section which is part of a group, and is to be retained or discarded with the
group as a whole, is identified by a new section header attribute: SHF_GROUP
This section is a member (perhaps the only one) of a group of sections, and the
linker should retain or discard all or none of the members. This section must be
referenced in a SHT_GROUP section. This attribute flag may be set in any section
header, and no other modification or indication is made in the grouped sections.
All additional information is contained in the associated SHT_GROUP section.

SHT_GROUP: Section Group Definition
-------------------------------------
Represents a group section.

The section group's sh_link field identifies a symbol table section, and its
sh_info field the index of a symbol in that section. The name of that symbol is
treated as the identifier of the section group.

More information: https://mentorembedded.github.io/cxx-abi/abi/prop-72-comdat.html

Added a lot of extensive tests, that tests functionality.

llvm-svn: 230195
2015-02-23 00:30:00 +00:00
Shankar Easwaran de4a31909f [ELF] Add .gnu.linkonce support.
When the GNU linker sees two input sections with the same name, and the name
starts with ".gnu.linkonce.", the linker will only keep one copy and discard the
other. Any section whose name starts with “.gnu.linkonce.” is a COMDAT section.

Some architectures like Hexagon use this section to store floating point constants,
that need be deduped.

This patch adds gnu.linkonce functionality to the ELFReader.

llvm-svn: 230194
2015-02-23 00:04:49 +00:00
Shankar Easwaran a1d3637f3d [Core,MachO,Test] Remove trailing whitespace.
llvm-svn: 230192
2015-02-22 23:54:38 +00:00
Shankar Easwaran e44fc87cde [Core] Fix handling of Section Groups.
There is code(added by me) in the YAMLReader which isn't correct when it handles references
for section groups. The test case was also checking for wrong outputs.

This fixes the bug and the testcase so that they check for proper outputs.

llvm-svn: 230190
2015-02-22 23:40:58 +00:00
Shankar Easwaran 45b392d6cf [ELF][X86_64] R_X86_64_16 relocation support
llvm-svn: 230189
2015-02-22 23:32:34 +00:00
Shankar Easwaran b8301da4a1 [ELF] Fix References being ignored.
The ELFReader was skipping references for sections that contained relocations.

This fixes the bug.

llvm-svn: 230127
2015-02-21 04:42:43 +00:00
Rui Ueyama 2c64aef35f Remove YAML/Native round-trip passes.
The round-trip passes were introduced in r193300. The intention of
the change was to make sure that LLD is capable of reading end
writing such file formats.

But that turned out to be yet another over-designed stuff that had
been slowing down everyday development.

The passes ran after the core linker and before the writer. If you
had an additional piece of information that needs to be passed from
front-end to the writer, you had to invent a way to save the data to
YAML/Native. These passes forced us to do that even if that data
was not needed to be represented neither in an object file nor in
an executable/DSO. It doesn't make sense. We don't need these passes.

http://reviews.llvm.org/D7480

llvm-svn: 230069
2015-02-20 22:10:28 +00:00
Rui Ueyama 11f42aa285 PECOFF: Fix base relocation for ImageBase.
This is yet another edge case of base relocation for symbols. Absolute
symbols are in general not target of base relocation because absolute
atom is a way to point to a specific memory location. In r229816, I
removed entries for absolute atoms from the base relocation table
(so that they won't be fixed by the loader).

However, there was one exception -- ImageBase. ImageBase points to the
start address of the current image in memory. That needs to be fixed up
at load time. This patch is to treat the symbol in a special manner.

llvm-svn: 229961
2015-02-20 03:35:59 +00:00
Rui Ueyama 3966c61536 PECOFF: Fix base relocation for an absolute symbol.
Previously we wrongly emitted a base relocation entry for an absolute symbol.
That made the loader to rewrite some instruction operands with wrong values
only when a DLL is not loaded at the default address. That caused a
misterious crash of some executable.

Absolute symbols will of course never change value wherever the binary is
loaded to memory. We shouldn't emit base relocations for absolute symbols.

llvm-svn: 229816
2015-02-19 04:22:27 +00:00
Rui Ueyama 3e6490f1e8 PECOFF: use llvm-readobj to dump .reloc section
When this test was written, no llvm tool could print out contents
of base relocation section. Now llvm-readobj is able to dump it in
a text format. Use that tool to make this test readable.

llvm-svn: 229814
2015-02-19 04:02:17 +00:00
Rui Ueyama 92b5979cb5 PECOFF: Fix symbol aliases
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
2015-02-18 23:11:48 +00:00
Will Newton 8d62e098ef Fix AArhc64 ELF test failure on Windows
The atoms may be processed in different orders on different systems
based on allocated addresses. This is a bit unfortunate as it would
be nice to have error messages emitted in order of file contents.
However we are emitting errors inside a parallel_for_each so even if
we stabilize the order of atom processing we would need to do some
further work in order to ensure that thread scheduling doesn't perturb
the order of errors. For now switch to using CHECK-DAG instead of CHECK.

llvm-svn: 229487
2015-02-17 11:16:54 +00:00
Simon Atanasyan fbe1348ef4 [Mips] Read GP0 value from .MIPS.options section
llvm-svn: 229442
2015-02-16 21:52:43 +00:00
Simon Atanasyan 371e1128b3 [Mips] Show error if MIPS_REGINFO section has invalid size
llvm-svn: 229441
2015-02-16 21:52:35 +00:00
Will Newton 6b3f59b6a9 ELF/AArch64: Add support for checking for ABS32 overflow
Add support for checking overflow when applying a R_AARCH64_ABS32
relocation and add a test to ensure it behaves correctly.

llvm-svn: 229072
2015-02-13 06:22:31 +00:00
Shankar Easwaran 7d71622c8f [ELF] Insert wrap symbols into a set.
Symbols specified by --wrap was being inserted into a vector, change this to
insert into a set, so that we have unique entries.

llvm-svn: 228968
2015-02-12 22:37:27 +00:00
Shankar Easwaran 2df0c3efd6 [ELF] Support --wrap option
Use a wrapper function for symbol. Any undefined reference to symbol will be
resolved to "__wrap_symbol". Any undefined reference to "__real_symbol" will be
resolved to symbol.

This can be used to provide a wrapper for a system function. The wrapper
function should be called "__wrap_symbol". If it wishes to call the system
function, it should call "__real_symbol".

Here is a trivial example:

void * __wrap_malloc (size_t c)
{
  printf ("malloc called with %zu\n", c);
  return __real_malloc (c);
}

If you link other code with this file using --wrap malloc, then all calls
to "malloc" will call the function "__wrap_malloc" instead. The call to
"__real_malloc" in "__wrap_malloc" will call the real "malloc" function.

llvm-svn: 228906
2015-02-12 05:02:46 +00:00
Denis Protivensky e35908b18f [ELF][ARM] Add veneer generation to branch instructions
When calling ARM code from Thumb and vice versa,
a veneer that switches instruction set should be generated.
Added veneer generation for ARM_JUMP24 ARM_THM_JUMP24 instructions.

Differential Revision: http://reviews.llvm.org/D7502

llvm-svn: 228680
2015-02-10 09:31:42 +00:00
Rui Ueyama 55240af6a3 Remove trailing space.
llvm-svn: 228643
2015-02-10 01:06:14 +00:00
Davide Italiano 1fd20ff599 [ELF] Implement --strip-all/-s
Differential Revision:	D7489
Reviewed by:	shankarke

llvm-svn: 228533
2015-02-08 19:42:15 +00:00
Rui Ueyama f54e4fd3c6 PECOFF: Move error check for invalid command line combination to validateImpl.
llvm-svn: 228461
2015-02-06 23:09:13 +00:00
Rui Ueyama 0076215b88 MachO: Move LayoutPass to MachO directory.
The real user of the LayoutPass is now only Mach-O, so move that
pass out of the common directory to Mach-O directory.

"Core" architecture were using the LayoutPass. I modified that
to use a simple OrderPass. I think no one actually have authority
what feature should be in Core and what's not, but I believe the
LayoutPass is not very suitable for Core. Before more code starts
depending on the complex pass, it's better to remove that from
Core.

I could have simplified that pass because Mach-O is the only user
of the LayoutPass. For example, the second parameter of the
LayoutPass constructor can be converted from optional to mandatory.
I didn't do that in this patch to keep it simple. I'll do in a
followup patch.

http://reviews.llvm.org/D7311

llvm-svn: 228341
2015-02-05 20:05:33 +00:00
Rui Ueyama df7d133cdf PECOFF: Fix I386_DIR32 relocation to an absolute symbol
Previously, we incorrectly added the image base address to an absolute
symbol address (that calculation doesn't make any sense) if an
IMAGE_REL_I386_DIR32 relocation is applied to an absolute symbol.

This patch fixes the issue. With this fix, we can link Bochs using LLD.
(Choosing Bochs has no special meaining -- I just picked it up as a
test program and found it didn't work.) This also fixes one of the
issues we currently have to link Chromium using LLD.

llvm-svn: 228279
2015-02-05 07:22:53 +00:00
Shankar Easwaran d67bcb5f5c [ELF] Dont discard sections in the input file.
The reader was discarding certain types of sections from the input file.

llvm-svn: 228268
2015-02-05 02:56:06 +00:00
Denis Protivensky b635ae8388 [lld][ARM] Add relocations to perform function calls
Added relocations to perform function calls with and without passing arguments.
ARM-only, Thumb-only and mixed mode code generations are supported.
Only simple veneers (direct instruction modification) are supported as ARM-Thumb interwork.

Differential Revision: http://reviews.llvm.org/D7223

llvm-svn: 227961
2015-02-03 10:48:37 +00:00
Davide Italiano 5cbde851ed [ELF] Support for parsing OUTPUT command in LinkerScript
Differential Revision:	D7326
Reviewed by:	rafaelauler, shankarke, ruiu

llvm-svn: 227786
2015-02-02 06:21:23 +00:00
Shankar Easwaran d6f73ac366 [test] Add test for section groups and deadstrip
This adds a test that deadstrip should preserve the section group even if there
is only one reference to a function in the group.

llvm-svn: 227711
2015-02-01 05:47:02 +00:00
Shankar Easwaran 0f011fdcdf [ELF] Set order of ctors/dtors section
llvm-svn: 227707
2015-02-01 03:21:57 +00:00
Rui Ueyama 33ab83bc4b ELF: Don't use LayoutPass.
Previously we applied the LayoutPass to order atoms and then
apply elf::ArrayOrderPass to sort them again. The first pass is
basically supposed to sort atoms in the normal fashion (which
is to sort symbols in the same order as the input files).
The second pass sorts atoms in {init,fini}_array.<priority> by
priority.

The problem is that the LayoutPass is overkill. It analyzes
references between atoms to make a decision how to sort them.
It's slow, hard to understand, and above all, it doesn't seem
that we need its feature for ELF in the first place.

This patch remove the LayoutPass from ELF pass list. Now all
reordering is done in elf::OrderPass. That pass sorts atoms by
{init,fini}_array, and if they are not in the special section,
they are ordered as the same order as they appear in the command
line. The new code is far easier to understand, faster, and
still able to create valid executables.

Unlike the previous layout pass, elf::OrderPass doesn't count
any attributes of an atom (e.g. permissions) except its
position. It's OK because the writer takes care of them if we
have to.

This patch changes the order of final output, although that's
benign. Tests are updated.

http://reviews.llvm.org/D7278

llvm-svn: 227666
2015-01-31 02:05:01 +00:00
Rui Ueyama a9a6f55840 ELF: Fix a bug in -l.
If a linker script is given with -l, LLD failed to read the file.
The bug was introduced in 227341.

llvm-svn: 227610
2015-01-30 21:03:19 +00:00
Rui Ueyama c4038ab5bf PECOFF: Do not use LayoutPass and instead use simpler one.
The LayoutPass is one of the slowest pass. This change is to skip
that pass. This change not only improve performance but also improve
maintainability of the code because the LayoutPass is pretty complex.

Previously we used the LayoutPass to sort all atoms in a specific way,
and reorder them again for PE/COFF in GroupedSectionPass.

I spent time on improving and fixing bugs in the LayoutPass (e.g.
r193029), but the pass is still hard to understand and hard to use.
It's better not to depend on that if we don't need. For PE/COFF, we
just wanted to sort atoms in the same order as the file order in the
command line.

The feature we used in the LayoutPass is now simplified to
compareByPosition function in OrderPass.cpp. The function is just 5
lines.

This patch changes the order of final output because it changes the
sort order a bit. The output is still correct, though.

llvm-svn: 227500
2015-01-29 22:12:50 +00:00
Greg Fitzgerald df0f5cd474 Remove PPC ELF target
Differential Revision: http://reviews.llvm.org/D7225

llvm-svn: 227320
2015-01-28 16:37:43 +00:00