Commit Graph

122 Commits

Author SHA1 Message Date
George Rimar 5a3dcf4edf [ELF] - Do not call doInitSymbols for all ELFTs
It looks a bit wierd that we have to initialize symbols for all ELFT 
types when we use only one ELFT for link. We can only init those
that we need. Patch fixes it.

Differential revision: http://reviews.llvm.org/D18047

llvm-svn: 263133
2016-03-10 17:38:49 +00:00
Rafael Espindola e090fb2891 ELF: Remove non-standard ELF features from AMDGPU target.
Patch by Tom Stellard!

llvm-svn: 263063
2016-03-09 21:37:22 +00:00
Rafael Espindola 4f29c1a337 lto: Record visibility in defined symbols.
llvm-svn: 262835
2016-03-07 17:14:36 +00:00
George Rimar 2f0fab53e4 [ELF] - Simplify a SymbolBody class interface a bit.
Get rid of few accessors in that class, and replace
them with direct fields access.

Differential revision: http://reviews.llvm.org/D17879

llvm-svn: 262796
2016-03-06 06:26:18 +00:00
Davide Italiano 255730cdc5 [ELF] Generalize symbol type handling.
SymbolBody constructor and friends take isFunc and isTLS boolean arguments.
ELF symbols have already a type so than be easily passed as argument.
If we want to support another type, this scheme is not good enough, that is,
the current code logic would require passing another `bool isObject` around.
Up to two argument, this stretching exercise was a little bit goofy but
still acceptable, but with more types to support, is just too much, IMHO.

Change the code so that the type is passed instead.

Differential Revision:   http://reviews.llvm.org/D17871

llvm-svn: 262684
2016-03-04 01:55:28 +00:00
George Rimar aa4dc20f09 [ELF] - Create _DYNAMIC symbol for dynamic output
lld needs to provide _DYNAMIC symbol when creating a shared library
both bfd and gold do that.

This should fix the https://llvm.org/bugs/show_bug.cgi?id=26732

Differential revision: http://reviews.llvm.org/D17607

llvm-svn: 262348
2016-03-01 16:23:13 +00:00
Rafael Espindola e0df00b91f Rename elf2 to elf.
llvm-svn: 262159
2016-02-28 00:25:54 +00:00
Rui Ueyama 72acaa1d17 Add comment on AMDGPU that the difference has no obvious reason.
llvm-svn: 262026
2016-02-26 15:39:26 +00:00
George Rimar 9e8593949d Description of symbols is avalable here:
https://docs.oracle.com/cd/E53394_01/html/E54766/u-etext-3c.html

It is said that:
_etext - The address of _etext is the first 
location after the last read-only loadable segment.

_edata - The address of _edata is the first 
location after the last read-write loadable segment.

_end - If the address of _edata is greater than the address 
of _etext, the address of _end is same as the address of _edata.

In real life _end and _edata has different values for that case.
Both gold/bfd set _edata to the end of the last non SHT_NOBITS section.
This patch do the same for consistency.

It should fix the https://llvm.org/bugs/show_bug.cgi?id=26729.

Differential revision: http://reviews.llvm.org/D17601

llvm-svn: 262019
2016-02-26 14:36:36 +00:00
Rui Ueyama 0b28952993 ELF: Implement ICF.
This patch implements the same algorithm as LLD/COFF's ICF. I'm
not going to repeat the same description about how it works, so you
want to read the comment in ICF.cpp in this patch if you want to know
the details. This algorithm should be more powerful than the ICF
algorithm implemented in GNU gold. It can even merge mutually-recursive
functions (which is harder than one might think).

ICF is a fairly effective size optimization. Here are some examples.

 LLD:   37.14 MB -> 35.80 MB (-3.6%)
 Clang: 59.41 MB -> 57.80 MB (-2.7%)

The lacking feature is "safe" version of ICF. This merges all
identical sections. That is not compatible with a C/C++ language
requirement that two distinct functions must have distinct addresses.

But as long as your program do not rely on the pointer equality
(which is in many cases true), your program should work with the
feature. LLD works fine for example.

GNU gold implements so-called "safe ICF" that identifies functions
that are safe to merge by heuristics -- for example, gold thinks
that constructors are safe to merge because there is no way to
take an address of a constructor in C++. We have a different idea
which David Majnemer suggested that we add NOPs at beginning of
merged functions so that two or more pointers can have distinct
values. We can do whichever we want, but this patch does not
include neither.

http://reviews.llvm.org/D17529

llvm-svn: 261912
2016-02-25 18:43:51 +00:00
Rafael Espindola 148445ef98 Add support for weak symbols in LTO.
llvm-svn: 261881
2016-02-25 16:25:41 +00:00
Rui Ueyama c89bff2ce1 Handle bitcode files in archive files with --whole-archive.
This patch moves BitcodeFile instantiation into createObjectFile.
Previously, we handle bitcode files outside that function and did
not handle for --whole-archive.

http://reviews.llvm.org/D17527

llvm-svn: 261663
2016-02-23 18:17:11 +00:00
Rafael Espindola 6feecec0b0 Handle undef symbols in LTO.
This also handles bc files is archives.

llvm-svn: 261374
2016-02-19 22:50:16 +00:00
Rafael Espindola 9f77ef0c08 Add initial LTO support.
llvm-svn: 260726
2016-02-12 20:54:57 +00:00
Rafael Espindola a0a65f973a Use the plt entry as the address of some symbols.
This is the function equivalent of a copy relocation.

Since functions are expected to change sizes, we cannot use copy
relocations. In situations where one would be needed, what is done
instead is:
* Create a plt entry
* Output an undefined symbol whose addr is the plt entry.

The dynamic linker makes sure any shared library uses the plt entry as
the function address.

llvm-svn: 260224
2016-02-09 15:11:01 +00:00
Rafael Espindola abebed982a Rename IsUsedInDynamicReloc to MustBeInDynSym.
The variable was marking various cases where a symbol must be included
in the dynamic symbol table. Being used by a dynamic relocation was only
one of them.

llvm-svn: 259889
2016-02-05 15:27:15 +00:00
Rui Ueyama 512c61df1c Define SymbolBody::getSize instead of getSymSize(SymbolBody&). NFC.
llvm-svn: 259613
2016-02-03 00:12:24 +00:00
George Rimar 5c36e5938d [ELF] Implemented -Bsymbolic-functions command line option
-Bsymbolic-functions: 
When creating a shared library, bind references to global 
function symbols to the definition within the shared library, if any.

This patch also fixed behavior of already existent -Bsymbolic:
previously PLT entries were created even if -Bsymbolic was specified.

Differential revision: http://reviews.llvm.org/D16411

llvm-svn: 259481
2016-02-02 09:28:53 +00:00
Rui Ueyama 71c066d8cf ELF: Include archive names in error messages.
If object files are drawn from archive files, the error message should
be something like "conflict symbols in foo.a(bar.o) and baz.o" instead
of "conflict symbols in bar.o and baz.o". This patch implements that.

llvm-svn: 259475
2016-02-02 08:22:41 +00:00
Rui Ueyama b5a6970ace ELF: Teach SymbolBody about how to get its addresses.
Previously, the methods to get symbol addresses were somewhat scattered
in many places. You can use getEntryAddr returns the address of the symbol,
but if you want to get the GOT address for the symbol, you needed to call
Out<ELFT>::Got->getEntryAddr(Sym). This change adds new functions, getVA,
getGotVA, getGotPltVA, and getPltVA to SymbolBody, so that you can use
SymbolBody as the central place to ask about symbols.

http://reviews.llvm.org/D16710

llvm-svn: 259404
2016-02-01 21:00:35 +00:00
George Rimar 02ca17906d [ELF] - Symbols from object files that override symbols in DSO are added to .dynsym table.
Main executable did not export symbols that exist both in the main executable and in DSOs before this patch.
Symbols from object files that override symbols in DSO should be added to .dynsym table.

Differential revision: http://reviews.llvm.org/D16405

llvm-svn: 258672
2016-01-25 08:44:38 +00:00
Rafael Espindola 65e80b963a Rename IgnoredWeak to Ignored.
Thanks to Rui for the suggestion.

llvm-svn: 258189
2016-01-19 21:19:52 +00:00
Rafael Espindola 3a6a0a0109 Delete addIgnoredStrong.
It is not needed now that we resolve symbols is shared libraries
correctly.

llvm-svn: 258104
2016-01-19 00:05:54 +00:00
Rafael Espindola 0bc0c02387 Prefer symbols from .o over .so.
This matches the behavior of gold and bfd ld.

llvm-svn: 258102
2016-01-18 23:54:05 +00:00
Rui Ueyama df1545163f Update comment for __cxa_demangle again to make it precise.
Thanks for Ed Maste for the suggestion.

llvm-svn: 257685
2016-01-13 22:09:09 +00:00
Rui Ueyama e16d1b0a9c Update comment for __cxa_demangle.
llvm-svn: 257678
2016-01-13 21:39:40 +00:00
Rui Ueyama 5fa978b4c0 Attempt to make FreeBSD buildbot green.
It seems that __cxa_demangle function on the buildbot tried to demangle
a variable "tlsvar" as a C++ symbol. Do not call that function unless
it does not start with "_Z" which is the prefix of mangled names.

llvm-svn: 257661
2016-01-13 19:40:13 +00:00
Rui Ueyama a4a628fb51 Demangle symbols when including them in error messages.
llvm-svn: 257647
2016-01-13 18:55:39 +00:00
Rui Ueyama 09eb0b3b3f Rename IgnoredUndef -> Ignored since it is not an undefined symbol.
Also rename Ignored -> IgnoredWeak and IgnoredStrong -> Ignored,
since strong symbol is a norm.

llvm-svn: 257507
2016-01-12 19:24:55 +00:00
Simon Atanasyan 188558e5eb [ELF][MIPS] Prevent substitution of _gp_disp symbol
On MIPS O32 ABI, _gp_disp is a magic symbol designates offset between
start of function and gp pointer into GOT. To make seal with such symbol
we add new method addIgnoredStrong(). It adds ignored symbol with global
binding to prevent the symbol substitution. The addIgnored call is not
enough here because this call adds a weak symbol which might be
substituted by symbol from shared library.

Differential Revision: http://reviews.llvm.org/D16084

llvm-svn: 257449
2016-01-12 06:23:57 +00:00
Rui Ueyama 83cd6e00e9 Remove unnecessary `lld::`.
llvm-svn: 256970
2016-01-06 20:11:55 +00:00
Rui Ueyama 533c03078b Do not use templates to instantiate {Object,Shared}Files.
createELFFile looked complex because of its use of template,
so I want to keep it private within this file.

llvm-svn: 256880
2016-01-06 00:09:43 +00:00
Rui Ueyama a246e094bc Factor out static members from DefinedRegular.
This patch moves statically-allocated Elf_Sym objects out
of DefinedRegular class, so that the class definition becomes
smaller.

llvm-svn: 256408
2015-12-25 06:12:18 +00:00
Rafael Espindola 1119191c4f Make it possible to create common symbols from bitcode.
Since the only missing bit was the size, I just replaced the Elf_Sym
with the size.

llvm-svn: 256384
2015-12-24 16:23:37 +00:00
Rafael Espindola 02ce26a1b4 Delete DefinedAbsolute.
There are 3 symbol types that a .bc can provide during lto: defined,
undefined, common.

Defined and undefined symbols have already been refactored. I was
working on common and noticed that absolute symbols would become an
oddity: They would be the only symbol type present in a .o but not in
a.bc.

Looking a bit more, other than the special section number they were only
used for special rules for computing values. In that way they are
similar to TLS, and we don't have a DefinedTLS.

This patch deletes it. With it we have a reasonable rule of the thumb
for having a symbol kind: It exists if it has special resolution
semantics.

llvm-svn: 256383
2015-12-24 14:22:24 +00:00
Rafael Espindola 4d4b06a0f8 Split Defined and DefinedElf.
This is similar to what was done for Undefined and opens the way for
having a symbol defined in bitcode.

llvm-svn: 256354
2015-12-24 00:47:42 +00:00
Rafael Espindola 5d7593bc59 Split Undefined and UndefinedElf.
I am working on adding LTO support to the new ELF lld.

In order to do that, it will be necessary to represent defined and
undefined symbols that are not from ELF files. One way to do it is to
change the symbol hierarchy to look like

Defined : SymbolBody
Undefined : SymbolBody

DefinedElf<ELFT> : Defined
UndefinedElf<ELFT> : Undefined

Another option would be to use bogus Elf_Sym, but I think that is
getting a bit too hackish.

This patch does the Undefined/UndefinedElf. Split. The next one
will do the Defined/DefinedElf split.

llvm-svn: 256289
2015-12-22 23:00:50 +00:00
Rui Ueyama 6be68525d0 Typedef uintX_t at beginning of a function just like others.
llvm-svn: 255853
2015-12-16 23:49:19 +00:00
Igor Kudrin b044af50f2 [ELF] Define symbols "_end" and "end" if referenced.
These symbols are expected to point to the end of the data segment.

Implements http://llvm.org/pr25528.

Differential Revision: http://reviews.llvm.org/D14833

llvm-svn: 253637
2015-11-20 02:32:35 +00:00
Rui Ueyama 86696f38ea ELF2: Avoid bitwise-OR hack. NFC.
The previous code is too clever that that needs a bit more
brain power than this new code.

llvm-svn: 250934
2015-10-21 19:41:03 +00:00
Rui Ueyama 8f2c4da65a ELF2: Rename getMostConstrainingVisibility -> getVisibility. NFC.
The previous name was too long.

llvm-svn: 250920
2015-10-21 18:13:47 +00:00
Rui Ueyama aca48ffb41 ELF2: Inititalize other symbols only once as well.
llvm-svn: 249645
2015-10-08 00:44:28 +00:00
Rui Ueyama 833ce281db ELF2: Make member variable names shorter.
I'm going to use them in other patches, and the names feel too long
despite their narrow scope.

llvm-svn: 249642
2015-10-08 00:29:00 +00:00
Rui Ueyama 9ea49c7948 ELF2: Initialize SyntheticOptional only once.
llvm-svn: 249636
2015-10-07 23:46:11 +00:00
Rafael Espindola 8e5560d894 Don't complain about symbols showing up in multible shared libraries.
llvm-svn: 248381
2015-09-23 14:23:59 +00:00
Rafael Espindola 9d06ab6ded Rename Chunks.(h|cpp) to InputSection.(h|cpp). NFC.
llvm-svn: 248226
2015-09-22 00:01:39 +00:00
Rui Ueyama 6666f6ad73 ELF2: Reduce nesting by returning early. NFC.
llvm-svn: 247168
2015-09-09 17:55:09 +00:00
Rui Ueyama 7da94a58a0 ELF2: Return early. NFC.
llvm-svn: 247165
2015-09-09 17:40:51 +00:00
Rafael Espindola 18173d420e Start adding support for symbols in shared libraries.
llvm-svn: 247019
2015-09-08 15:50:05 +00:00
Michael J. Spencer 1b348a68e5 [elf2] Add basic archive file support.
llvm-svn: 246886
2015-09-04 22:28:10 +00:00
Rafael Espindola 78471f0ec1 Merge visibility from all symbols with the same name.
The ELF spec says:

... if any reference to or definition of a name is a symbol with a
non-default visibility attribute, the visibility attribute must be
propagated to the resolving symbol in the linked object. If different
visibility attributes are specified for distinct references to or
definitions of a symbol, the most constraining visibility attribute
must be propagated to the resolving symbol in the linked object. The
attributes, ordered from least to most constraining, are:
STV_PROTECTED, STV_HIDDEN and STV_INTERNAL.

llvm-svn: 246603
2015-09-01 23:12:52 +00:00
Rafael Espindola f31f9617ca Remember the maximum alignment used to refer to a common symbol.
llvm-svn: 246517
2015-09-01 01:19:12 +00:00
Rafael Espindola daa92a6193 Keep the largest common symbol.
This requires templating some functions over ELFT, but that opens other cleanup
opportunities for future patches.

llvm-svn: 246405
2015-08-31 01:16:19 +00:00
Rafael Espindola 30e1797b38 Turn resolution.s into an exhaustive testcase.
Now that we print a symbol table and all symbol kinds are at least declared,
we can test all combinations that don't produce an error.

This also includes a few fixes to keep the test passing:

* Keep the strong symbol in a weak X strong pair
* Handle common symbols.

The common X common case will be finished in a followup patch.

llvm-svn: 246401
2015-08-30 23:17:30 +00:00
Rafael Espindola 3a63f3fb22 Add support for weak absolute symbols.
On ELF being weak is independent of what we call the kind of the symbol. So
this also makes the code simpler.

llvm-svn: 246326
2015-08-28 20:19:34 +00:00
Rafael Espindola 0e0c1901c9 Start adding support for absolute symbols.
llvm-svn: 246147
2015-08-27 12:40:06 +00:00
Rafael Espindola 1bd885aba4 ELF: Also record the type of undefined symbols.
Tested with a weak undefined. Testing with a plain undefined will have to wait
for support for -shared.

llvm-svn: 245069
2015-08-14 16:46:28 +00:00
Rui Ueyama 4f89fdad9f ELF2: Make Defined{Regular,Weak} ctors look the same as other SymbolBody ctors.
llvm-svn: 244701
2015-08-11 23:37:25 +00:00
Rafael Espindola 76e24ea955 Add support for weak undefined symbols.
llvm-svn: 244640
2015-08-11 17:57:05 +00:00
Rafael Espindola 791e9f9c59 Remove unused templating.
llvm-svn: 244639
2015-08-11 17:51:57 +00:00
Rafael Espindola b13df6582a Add support for weak symbols.
llvm-svn: 244636
2015-08-11 17:33:02 +00:00
Rafael Espindola ae1b23bd61 Use real values for DefindeFirst and DefinedLast.
With this clang notices that switches are fully covered.

llvm-svn: 244632
2015-08-11 17:10:02 +00:00
Rafael Espindola df1e05a26c Delete broken code.
This was using a hard coded string table and getting it for every symbol.

The symbol name was already available.

llvm-svn: 244220
2015-08-06 15:33:21 +00:00
Rafael Espindola 49a2ca6ddd bar
llvm-svn: 244219
2015-08-06 15:33:19 +00:00
Rafael Espindola e3335d8a66 Delete dead code.
llvm-svn: 244040
2015-08-05 13:26:54 +00:00
Michael J. Spencer cdae0a4e2d [ELF2] Devirtualize SymbolBody.
llvm-svn: 243496
2015-07-28 22:58:25 +00:00
Rui Ueyama fdbbcdad87 ELF2: Inline very small functions.
llvm-svn: 243323
2015-07-27 20:39:04 +00:00
Rui Ueyama a7ccb2926f ELF2: Devirtualize SymbolBody::compare. NFC.
This is to make it consistent with COFF.

llvm-svn: 243321
2015-07-27 20:39:01 +00:00
Michael J. Spencer 84487f1174 [ELF2] Add a new ELF linker based on the new PE/COFF linker.
Differential Revision: http://reviews.llvm.org/D11188

llvm-svn: 243161
2015-07-24 21:03:07 +00:00
Michael J. Spencer bae540e945 Revert ELF port. Posting to mailing list.
llvm-svn: 242118
2015-07-14 04:49:48 +00:00
Michael J. Spencer f754b1fe12 Put explicit template instantiations in the correct namespace.
llvm-svn: 242093
2015-07-14 00:22:00 +00:00
Michael J. Spencer 8a4145411f Initial ELF port.
This is a direct port of the new PE/COFF linker to ELF.

It can take a single object file and generate a valid executable that executes at the first byte in the text section.

llvm-svn: 242088
2015-07-13 23:48:06 +00:00