Commit Graph

135 Commits

Author SHA1 Message Date
Rafael Espindola 8e232573a8 Simplify now that this is only used for global symbols.
llvm-svn: 285966
2016-11-03 20:48:57 +00:00
Rafael Espindola e19abab9a7 Now that the ELFFile constructor does nothing, create it when needed.
This avoids duplicating the buffer in InputFile.

llvm-svn: 285965
2016-11-03 20:44:50 +00:00
Rafael Espindola 6dcf4c6859 Change how we store the symbol table.
Instead of remembering a raw Elf_Shdr, store the symbol table proper
and the index of the first non local.

This moves error handling upfront and simplifies it.

llvm-svn: 285933
2016-11-03 16:55:44 +00:00
Rafael Espindola 21d8be9a4e Initialize the StringTable early and do it only once.
llvm-svn: 285926
2016-11-03 15:43:47 +00:00
Rafael Espindola 212b93d816 Delete dead code.
llvm-svn: 285922
2016-11-03 15:01:12 +00:00
Rafael Espindola 6d18d388c5 Pass the section table around instead of recomputing it.
llvm-svn: 285904
2016-11-03 13:24:29 +00:00
George Rimar db37e5b5c2 [ELF] - Removed unused method declaration. NFC.
llvm-svn: 285884
2016-11-03 08:20:57 +00:00
Rafael Espindola 7c7abafd81 Pass the sections to getShtGroupSignature.
This avoids fetching it again from the object.

llvm-svn: 285875
2016-11-03 02:28:13 +00:00
Rui Ueyama 7556f6b276 Reduce number of classes by merging DIHelper with ObjectFile.
DIHelper is a class having only one member, and ObjectFile has
a unique pointer to a DIHelper. So we can directly have ObjectFile
have the member.

Differential Revision: https://reviews.llvm.org/D26223

llvm-svn: 285850
2016-11-02 18:42:13 +00:00
Rafael Espindola ec05a574fe Don't fetch the section string table multiple times. NFC.
llvm-svn: 285755
2016-11-01 21:48:00 +00:00
Rafael Espindola 5c9e8f5e52 Replace GAlloc with a template function.
This patch replaces GAlloc<ELFT>::<sometype>.Allocate() with
alloc<sometype<ELFT>>().

Patch by Rui!

llvm-svn: 285748
2016-11-01 21:06:40 +00:00
Eugene Leviant c4681203e1 Allow fetching source line, when multiple "AX" sections present
Differential revision: https://reviews.llvm.org/D26070

llvm-svn: 285680
2016-11-01 09:17:50 +00:00
Rui Ueyama 55518e7dd8 Consolidate BumpPtrAllocators.
Previously, we have a lot of BumpPtrAllocators, but all these
allocators virtually have the same lifetime because they are
not freed until the linker finishes its job. This patch aggregates
them into a single allocator.

Differential revision: https://reviews.llvm.org/D26042

llvm-svn: 285452
2016-10-28 20:57:25 +00:00
Rui Ueyama 44fa48f986 Define ~DIHelper::DIHelper() in .cpp.
llvm-svn: 285347
2016-10-27 21:26:57 +00:00
Rafael Espindola 093abab817 Don't create a dummy ELF to process a binary file.
Now that it is easy to create input section and symbols, this is
simple.

llvm-svn: 285322
2016-10-27 17:45:40 +00:00
Rafael Espindola 7cc713adcb Store OSABI in Config.
This allows us to set a value for it based on -m.

llvm-svn: 285294
2016-10-27 14:00:51 +00:00
Rafael Espindola a8631e3887 Use fewer allocators.
Instead of having 3 section allocators per file, have 3 for all files.

This is a substantial performance improvement for some cases. Linking
chromium without gc speeds up by 1.065x.

This requires using _exit in fatal since we have to avoid destructing
an InputSection if fatal is called from the constructor.

Thanks to Rui for the suggestion.

llvm-svn: 285290
2016-10-27 13:32:32 +00:00
Rafael Espindola 5da1d88492 Reduce the number of allocators.
We used to have one allocator per file, which reduces the advantage of
using an allocator in the first place.

This is a small speed up is most cases. The largest speedup was in
1.014X in chromium no-gc. The largest slowdown was scylla at 1.003X.

llvm-svn: 285205
2016-10-26 15:34:24 +00:00
Eugene Leviant b380b24e6e [ELF] Better error reporting for undefined symbols
This patch make lld show following details for undefined symbol errors:
- file (line)
- file (function name)
- file (section name + offset)

Differential revision: https://reviews.llvm.org/D25826

llvm-svn: 285186
2016-10-26 11:07:09 +00:00
Rafael Espindola 8b2c8536e5 Use a CachedHashString for comdats too.
We were already using it in the larger sets/maps. This provides about
1% speedup in linking xul and chromium.

llvm-svn: 284862
2016-10-21 19:49:42 +00:00
Rui Ueyama 617d587432 Move code from InputFile to ELFCreator to decouple the two files.
Now that only one non-member function is exported from ELFCreator.h.
All the details are handled internally in ELFCreator.cpp file.

llvm-svn: 284786
2016-10-20 21:57:06 +00:00
George Rimar a4c7e74d4b [ELF] - Applied clang format. NFC.
llvm-svn: 284705
2016-10-20 08:36:42 +00:00
Rui Ueyama 673c9d9018 Add a helper function to define symbols.
Also replace std::copy with memcpy because in other places we are
using memcpy.

llvm-svn: 284700
2016-10-20 06:44:58 +00:00
Davide Italiano bcdd6c60a0 [ThinLTO] Avoid archive member collisions.
This fixes PR30665.

Differential Revision:  https://reviews.llvm.org/D25495

llvm-svn: 284034
2016-10-12 19:35:54 +00:00
Peter Smith 0760605ac5 [ELF][ARM] Garbage collection support for .ARM.exidx sections
.ARM.exidx sections have a reverse dependency on the section they have
a SHF_LINK_ORDER dependency on. In other words a .ARM.exidx section is
live only if the executable section it describes is live. We implement
this with a reverse dependency field in InputSection.

Adding the dependency to InputSection is the simplest implementation
but it could be moved out to a separate map if it were found to decrease
performance for non ARM targets.

Differential revision: https://reviews.llvm.org/D25234

llvm-svn: 283734
2016-10-10 10:10:27 +00:00
George Rimar b1f78d1202 [ELF] - Do not crash on invalid symbol index.
Relative to PR30540.

If .symtab has invalid type in elf, no bodies are created and any relocation
that tries to access them will fail.
The same can happen if symbol index is just incorrect.

This was revealed by "id_000005,sig_11,src_000000,op_flip2,pos_420"

Differential revision: https://reviews.llvm.org/D25025

llvm-svn: 283201
2016-10-04 09:02:42 +00:00
Davide Italiano 786d8e33db [ELF/LTO] Switch to the new resolution-based API.
Differential Revision:  https://reviews.llvm.org/D24492

llvm-svn: 282656
2016-09-29 00:40:08 +00:00
Rui Ueyama 38dbd3eea9 Simplify InputFile ownership management.
Previously, all input files were owned by the symbol table.
Files were created at various places, such as the Driver, the lazy
symbols, or the bitcode compiler, and the ownership of new files
was transferred to the symbol table using std::unique_ptr.
All input files were then free'd when the symbol table is freed
which is on program exit.

I think we don't have to transfer ownership just to free all
instance at once on exit.

In this patch, all instances are automatically collected to a
vector and freed on exit. In this way, we no longer have to
use std::unique_ptr.

Differential Revision: https://reviews.llvm.org/D24493

llvm-svn: 281425
2016-09-14 00:05:51 +00:00
Michael J. Spencer a9424f39c4 [ELF] Add support for -b binary
Implemented by building an ELF file in memory.

elf, default, and binary match gold behavior.

Differential Revision: https://reviews.llvm.org/D24060

llvm-svn: 281108
2016-09-09 22:08:04 +00:00
Simon Atanasyan 85c6b44817 [ELF][MIPS] Support .MIPS.abiflags section
This section supersedes .reginfo and .MIPS.options sections. But for now
we have to support all three sections for ABI transition period.

llvm-svn: 278482
2016-08-12 06:28:49 +00:00
Peter Collingbourne feee2103c6 COFF: Implement /linkrepro flag.
This flag is implemented similarly to --reproduce in the ELF linker.

This patch implements /linkrepro by moving the cpio writer and associated
utility functions to lldCore, and using that implementation in both linkers.

One COFF-specific detail is that we store the object file from which the
resource files were created in our reproducer, rather than the resource
files themselves. This allows the reproducer to be used on non-Windows
systems for example.

Differential Revision: https://reviews.llvm.org/D22418

llvm-svn: 276719
2016-07-26 02:00:42 +00:00
Rui Ueyama 429ef2af6a ELF: Include filenames in error messages.
llvm-svn: 275608
2016-07-15 20:38:28 +00:00
Rui Ueyama 3d9b26b4ad Inline traceUndefined function.
llvm-svn: 275531
2016-07-15 04:57:46 +00:00
Rui Ueyama 8b8d0055fe Fix memory leak.
Symbol's dtors are not called because they are allocated using
BumpPtrAllocators. So, members of std::unique_ptr type are not
freed when symbols are deallocated.

This patch is to allocate Thunks using BumpPtrAllocators.

llvm-svn: 274896
2016-07-08 17:58:54 +00:00
Rui Ueyama 5e64d3fb94 Refactor ELF type inference functions.
Previously, we initialized Config->EKind and Config->EMachine when
we instantiate ELF objects. That was not an ideal location to do that
because the logic was buried too deep inside a concrete logic.

This patch moves the code to the driver so that the initialization
becomes explicit.

Differential Revision: http://reviews.llvm.org/D21784

llvm-svn: 274089
2016-06-29 01:30:50 +00:00
Rui Ueyama d60dae8a6a Implement --trace-symbol=symbol option.
Patch by Shridhar Joshi.

This option provides names of all the link time modules which define and
reference symbols requested by user. This helps to speed up application
development by detecting references causing undefined symbols.
It also helps in detecting symbols being resolved to wrong (unintended)
definitions in case of applications containing multiple definitions for
same symbols with different types, bindings.

Implements PR28226.

llvm-svn: 273536
2016-06-23 07:00:17 +00:00
Rafael Espindola 65c65ce897 Don't include --start-lib/--end-lib files twice.
This should never happen with correct programs, but it is trivial
write a testcase where lld would crash or report duplicated
symbols. We now behave like when an archive is used and include the
file only once.

llvm-svn: 272724
2016-06-14 21:56:36 +00:00
Rui Ueyama 0b9a90364b Rename EHInputSection -> EhInputSection.
llvm-svn: 270532
2016-05-24 04:19:20 +00:00
Rafael Espindola 78db5a9dca Print member name in undefined symbol error.
llvm-svn: 268976
2016-05-09 21:40:06 +00:00
Simon Atanasyan add74f37f2 [ELF][MIPS] Read/write .MIPS.options section
MIPS N64 ABI introduces .MIPS.options section which specifies miscellaneous
options to be applied to an object/shared/executable file. LLVM as well as
modern versions of GNU tools read and write the only type of the options -
ODK_REGINFO. It is exact copy of .reginfo section used by O32 ABI.

llvm-svn: 268485
2016-05-04 10:07:38 +00:00
Peter Collingbourne 4f9527065c ELF: New symbol table design.
This patch implements a new design for the symbol table that stores
SymbolBodies within a memory region of the Symbol object. Symbols are mutated
by constructing SymbolBodies in place over existing SymbolBodies, rather
than by mutating pointers. As mentioned in the initial proposal [1], this
memory layout helps reduce the cache miss rate by improving memory locality.

Performance numbers:

           old(s) new(s)
Without debug info:
chrome      7.178  6.432 (-11.5%)
LLVMgold.so 0.505  0.502 (-0.5%)
clang       0.954  0.827 (-15.4%)
llvm-as     0.052  0.045 (-15.5%)
With debug info:
scylla      5.695  5.613 (-1.5%)
clang      14.396 14.143 (-1.8%)

Performance counter results show that the fewer required indirections is
indeed the cause of the improved performance. For example, when linking
chrome, stalled cycles decreases from 14,556,444,002 to 12,959,238,310, and
instructions per cycle increases from 0.78 to 0.83. We are also executing
many fewer instructions (15,516,401,933 down to 15,002,434,310), probably
because we spend less time allocating SymbolBodies.

The new mechanism by which symbols are added to the symbol table is by calling
add* functions on the SymbolTable.

In this patch, I handle local symbols by storing them inside "unparented"
SymbolBodies. This is suboptimal, but if we do want to try to avoid allocating
these SymbolBodies, we can probably do that separately.

I also removed a few members from the SymbolBody class that were only being
used to pass information from the input file to the symbol table.

This patch implements the new design for the ELF linker only. I intend to
prepare a similar patch for the COFF linker.

[1] http://lists.llvm.org/pipermail/llvm-dev/2016-April/098832.html

Differential Revision: http://reviews.llvm.org/D19752

llvm-svn: 268178
2016-05-01 04:55:03 +00:00
Rafael Espindola 156f4ee1c0 Use a single context for lto.
Using multiple context used to be a really big memory saving because we
could free memory from each file while the linker proceeded with the
symbol resolution. We are getting lazier about reading data from the
bitcode, so I was curious if this was still a good tradeoff.

One thing that is a bit annoying is that we still have to copy the
symbol names. The problem is that the names are stored in the Module and
get freed when we move the module bits during linking.

Long term I think the solution is to add a symbol table to the bitcode.
That way IRObject file will not need to use a Module or a Context and we
can drop it while still keeping a StringRef to the names.

This patch is still be an interesting medium term improvement.

When linking llvm-as without debug info this patch is a small speedup:

master: 29.861877513 seconds
patch: 29.814533787 seconds

With debug info the numbers are

master: 34.765181469 seconds
patch: 34.563351584 seconds

The peak memory usage when linking llvm-as with debug info was

master: 599.10MB
patch: 600.13MB
llvm-svn: 267921
2016-04-28 19:30:41 +00:00
Peter Collingbourne 21a12fc69a ELF: Create .gnu.version and .gnu.version_r sections when linking against versioned DSOs.
Differential Revision: http://reviews.llvm.org/D19464

llvm-svn: 267775
2016-04-27 20:22:31 +00:00
Peter Collingbourne 676c7cd1ed ELF: Move code to where it is used, and related cleanups. NFC.
Differential Revision: http://reviews.llvm.org/D19490

llvm-svn: 267637
2016-04-26 23:52:44 +00:00
Rafael Espindola 6c75238aca Call repl in getSymbolBody. NFC.
Every caller was doing it.

llvm-svn: 267603
2016-04-26 20:45:31 +00:00
Davide Italiano 9f8efffe29 [LTO] Create Undefined Bitcode symbol when we drop a comdat member.
Differential Revision:  http://reviews.llvm.org/D19389

llvm-svn: 267181
2016-04-22 18:26:33 +00:00
Rafael Espindola 197d6a882f This reverts commit r267154 and r267161.
It turns out that this will read data from the section to properly
handle Elf_Rel implicit addends.

Sorry for the noise.

Original messages:

Try to fix Windows lld build.

Move getRelocTarget to ObjectFile.
It doesn't use anything from the InputSection.

llvm-svn: 267163
2016-04-22 16:39:59 +00:00
Rafael Espindola ea4d177977 Move getRelocTarget to ObjectFile.
It doesn't use anything from the InputSection.

llvm-svn: 267154
2016-04-22 14:17:14 +00:00
Rui Ueyama f8baa66056 ELF: Implement --start-lib and --end-lib
start-lib and end-lib are options to link object files in the same
semantics as archive files. If an object is in start-lib and end-lib,
the object is linked only when the file is needed to resolve
undefined symbols. That means, if an object is in start-lib and end-lib,
it behaves as if it were in an archive file.

In this patch, I introduced a new notion, LazyObjectFile. That is
analogous to Archive file type, but that works for a single object
file instead of for an archive file.

http://reviews.llvm.org/D18814

llvm-svn: 265710
2016-04-07 19:24:51 +00:00
Rui Ueyama ec6aee0927 Do not allocate MipsReginfo using BumpPtrAllocator.
So that MipsReginfo's destructor will be called.

llvm-svn: 265512
2016-04-06 02:52:47 +00:00