Commit Graph

243 Commits

Author SHA1 Message Date
Rafael Espindola 0f7cedaa1e Create thunks before regular relocation scan.
We will need to do something like this to support range extension
thunks since that process is iterative.

Doing this also has the advantage that when doing the regular
relocation scan the offset in the output section is known and we can
just store that. This reduces the number of times we have to run
getOffset and I think will allow a more specialized .eh_frame
representation.

By itself this is already a performance win.

firefox
  master 7.295045737
  patch  7.209466989 0.98826892235
chromium
  master 4.531254468
  patch  4.509221804 0.995137623774
chromium fast
  master 1.836928973
  patch  1.823805241 0.992855612714
the gold plugin
  master 0.379768791
  patch  0.380043405 1.00072310839
clang
  master 0.642698284
  patch  0.642215663 0.999249070657
llvm-as
  master 0.036665467
  patch  0.036456225 0.994293213284
the gold plugin fsds
  master 0.40395817
  patch  0.404384555 1.0010555177
clang fsds
  master 0.722045545
  patch  0.720946135 0.998477367518
llvm-as fsds
  master 0.03292646
  patch  0.032759965 0.994943428477
scylla
  master 3.427376378
  patch  3.368316181 0.98276810292

llvm-svn: 276146
2016-07-20 17:58:07 +00:00
Rui Ueyama 941faa77ad Remove TargetInfo::getImageBase. NFC.
llvm-svn: 275447
2016-07-14 17:43:28 +00:00
Rui Ueyama 803b120ba1 Add GotEntrySize/GotPltEntrySize to ELF target.
Patch by H.J Lu.

For x86-64 psABI, the entry size of .got and .got.plt sections is 8
bytes for both LP64 and ILP32.  Add GotEntrySize and GotPltEntrySize
to ELF target instead of using size of ELFT::uint.  Now we can generate
a simple working x32 executable.

Differential Revision: http://reviews.llvm.org/D22288

llvm-svn: 275301
2016-07-13 18:55:14 +00:00
Rui Ueyama 484a49514f Rename VAStart -> ImageBase. NFC.
Config members are named after corresponding command line options.
This patch renames VAStart ImageBase so that they are in line with
--image-base.

Differential Revision: http://reviews.llvm.org/D22277

llvm-svn: 275298
2016-07-13 18:40:59 +00:00
Rui Ueyama e2efadced7 Remove Target::writeThunk.
Only MipsThunk were using the function, and the way how it wrote
thunk contents was different from ARM thunks. This patch makes
them consistent.

llvm-svn: 274997
2016-07-09 22:52:32 +00:00
Peter Smith fb05cd997c Recommit R274836 Add Thunk support framework for ARM and Mips
The TinyPtrVector of const Thunk<ELFT>* in InputSections.h can cause 
build failures on certain compiler/library combinations when Thunk<ELFT> 
is not a complete type or is an abstract class. Fixed by making Thunk<ELFT>
non Abstract.

type or is an abstract class 

llvm-svn: 274863
2016-07-08 16:10:27 +00:00
Peter Smith eeb827447e Revert R274836 Add Thunk support framework for ARM and Mips
This seems to be causing a buildbot failure on lld-x86_64-freebsd. Will
reproduce locally and fix. 

llvm-svn: 274841
2016-07-08 12:25:50 +00:00
Peter Smith de01b98a26 Add Thunk support framework for ARM and Mips
Generalise the Mips LA25 Thunk code and implement ARM and Thumb
    interworking Thunks.
    
    - Introduce a new module Thunks.cpp to store the Target Specific Thunk
      implementations.
    - DefinedRegular and Shared have a ThunkData field to record Thunk.
    - A Target can have more than one type of Thunk.
    - Support PC-relative calls to Thunks.
    - Support Thunks to PLT entries.
    - Existing Mips LA25 Thunk code integrated.
    - Support for ARMv7A interworking Thunks.
    
    Limitations:
    - Only one Thunk per SymbolBody, this is sufficient for all currently
      implemented Thunks.
    - ARM thunks assume presence of V6T2 MOVT and MOVW instructions.

    Differential revision: http://reviews.llvm.org/D21891

llvm-svn: 274836
2016-07-08 11:13:40 +00:00
Rui Ueyama c737ef5d21 Remove default values that vary depending on target.
llvm-svn: 272976
2016-06-16 23:50:25 +00:00
Rui Ueyama 4a90f57ef2 Rename PltZero -> PltHeader.
PltZero (or PLT[0]) was an appropriate name for the little code
we have at beginning of the PLT section when we only supported x86
since the code for x86 just fits in the first PLT slot.

It's not the case anymore. The code for ARM64 occupies first two
slots, so PltZero spans PLT[0] and PLT[1], for example.
This patch renames it to avoid confusion.

llvm-svn: 272913
2016-06-16 16:28:50 +00:00
Rui Ueyama c9fee5fee6 Eliminate unnecessary call of SymbolBody::getPltVA.
For ARM and MIPS, we don't need to call this function.
This patch passes a symbol instead of a PLT entry address
so that the target handler can call it if necessary.

llvm-svn: 272910
2016-06-16 16:14:50 +00:00
Rui Ueyama 3e097b1a06 Move a function declaration to a header.
llvm-svn: 272146
2016-06-08 14:35:22 +00:00
Rafael Espindola f807d47164 Rename TlsGdToLeSkip.
It will also be used for GT_TO_IE relaxations.

llvm-svn: 271813
2016-06-04 23:04:39 +00:00
Rafael Espindola 5c66b8260e Rename adjustRelaxGotExpr.
It will be used for more than just gots.

llvm-svn: 271812
2016-06-04 22:58:54 +00:00
Rafael Espindola e37d13b9ec Start adding tlsdesc support for aarch64.
This is mostly extracted from http://reviews.llvm.org/D18960.

The general idea for tlsdesc is that the two GD got entries are used
for a function pointer and its argument. The dynamic linker sets
both. In the non-dlopen case the dynamic linker sets the function to
the identity and the argument to the offset in the tls block.

All that the static linker has to do in the non-dlopen case is
relocate the code to point to the got entries and create a dynamic
relocation.

The dlopen case is more complicated, but can be implemented in another patch.

llvm-svn: 271569
2016-06-02 19:49:53 +00:00
George Rimar f10c8290fa [ELF] - Implemented support for test/binop relaxations from latest ABI.
Patch implements next relaxation from latest ABI:

"Convert memory operand of test and binop into immediate operand, where binop is one of adc, add, and, cmp, or,
sbb, sub, xor instructions, when position-independent code is disabled."

It is described in System V Application Binary Interface AMD64 Architecture Processor 
Supplement Draft Version 0.99.8 (https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-r249.pdf, 
B.2 "B.2 Optimize GOTPCRELX Relocations").

Differential revision: http://reviews.llvm.org/D20793

llvm-svn: 271405
2016-06-01 16:45:30 +00:00
Rafael Espindola a8433c1d1b Revert "bar"
This reverts commit r271365.
Sorry, wrong branch.

llvm-svn: 271366
2016-06-01 06:15:22 +00:00
Rafael Espindola 74540516ef bar
llvm-svn: 271365
2016-06-01 06:13:54 +00:00
George Rimar a8f9cf18ad Removed redundant argument. NFC.
llvm-svn: 270847
2016-05-26 13:37:12 +00:00
George Rimar 5c33b91bbe [ELF] - Implemented optimization for R_X86_64_GOTPCREL relocation.
System V Application Binary Interface AMD64 Architecture Processor Supplement Draft Version 0.99.8 
(https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-r249.pdf, B.2 "B.2 Optimize GOTPCRELX Relocations")
introduces possible relaxations for R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX.

That patch implements the next relaxation: 
mov foo@GOTPCREL(%rip), %reg => lea foo(%rip), %reg
and also opens door for implementing all other ones.

Implementation was suggested by Rafael Ávila de Espíndola with few additions and testcases by myself.

Differential revision: http://reviews.llvm.org/D15779

llvm-svn: 270705
2016-05-25 14:31:37 +00:00
Rafael Espindola fe3a2f1b81 Revert "Simplify. Thanks to Rui for the suggestion."
This reverts commit r270551.

Sorry, I commited the wrong branch :-(

llvm-svn: 270554
2016-05-24 12:12:06 +00:00
Rafael Espindola dba64b8ea4 Simplify. Thanks to Rui for the suggestion.
llvm-svn: 270551
2016-05-24 11:53:15 +00:00
Rafael Espindola 8818ca69dc Make tp offset computation target independent.
This adds direct support for computing offsets from the thread pointer
for both variants. Of the architectures we support, variant 1 is used
only by aarch64 (but that doesn't seem to be documented anywhere.)

llvm-svn: 270243
2016-05-20 17:41:09 +00:00
Rafael Espindola e4c86d83fe Drop vestigial support for UseLazyBinding=false.
Lazy binding is quite important for use case like a shared build of
llvm. Also, if someone wants to disable it, it is better done in the
compiler (disable plt generation).

The only reason to keep it is to make it easier to add a new
architecture. But it doesn't really help much as it is possible to start
with non lazy relocation and plt code but still let the generic part
create a dedicated .got.plt and .rela.plt.

llvm-svn: 269982
2016-05-18 21:03:36 +00:00
Rafael Espindola 4ee6cb3a70 Document and test the first few .got.plt entries.
llvm-svn: 268945
2016-05-09 18:12:15 +00:00
Rafael Espindola 38bd217d0c Delete getTlsGotRel.
It was an old hack to avoid duplicating expression computation, but that
is not needed with getExprRel.

llvm-svn: 268515
2016-05-04 15:51:23 +00:00
Rafael Espindola ebb04b9eb6 Simplify handling of hint relocations.
llvm-svn: 268501
2016-05-04 14:44:22 +00:00
Rafael Espindola b8ff59ac12 Rename isRelRelative
It was never a particularly good name and is now completely out of date.

llvm-svn: 267886
2016-04-28 14:34:39 +00:00
Simon Atanasyan 4ee2918e6e [ELF][MIPS] Remove getMipsGpAddr(). NFC
llvm-svn: 267673
2016-04-27 05:31:28 +00:00
Simon Atanasyan 1ef1bf87dc [ELF][MIPS] Move MIPS GOT header generation to the GotSection
MIPS is the only target requires GOT header. We already have MIPS
specific code in the `GotSection` class, so move MIPS GOT header
generation there and delete redundant stuff like `GotHeaderEntriesNum`
field and `writeGotHeader` method.

Differential Revision: http://reviews.llvm.org/D19465

llvm-svn: 267460
2016-04-25 20:25:05 +00:00
Rafael Espindola a6c4d2f197 Delete needsCopyRelImpl. It is redundant with getRelExpr.
llvm-svn: 267394
2016-04-25 12:05:56 +00:00
Rafael Espindola e26b50e71a Reduce templating. NFC.
llvm-svn: 267018
2016-04-21 17:37:11 +00:00
Rafael Espindola b312a740ae Delete the needsPlt target hook.
It can be made redundant with getRelExpr.

llvm-svn: 267012
2016-04-21 17:30:24 +00:00
Rafael Espindola 0c869a752e Moves needsPlt to Writer.cpp.
It was only used there.

llvm-svn: 267002
2016-04-21 16:57:32 +00:00
Rafael Espindola c6b17bdc29 Delete refersToGotEntry.
It can be computed from the expression.

llvm-svn: 266890
2016-04-20 17:30:22 +00:00
Rafael Espindola cc36a63f0b Move canRelaxTls to Writer.cpp. NFC.
llvm-svn: 266878
2016-04-20 14:41:55 +00:00
Rafael Espindola 6eda85ac1f Delete needsDynRelative.
It is now redundant. Writer.cpp can reason that 2 dynamic relocations
are needed: one to find the final got entry address and one to fill the
got entry.

llvm-svn: 266876
2016-04-20 14:36:24 +00:00
Rafael Espindola 5bf59728e2 Remove isGotRelative.
It is now redundant with the expression. While at it, handle both "X -
Got" and "Got - PC".

llvm-svn: 266607
2016-04-18 12:31:37 +00:00
Rafael Espindola 99c224787b Delete the now redundant pointsToLocalDynamicGotEntry.
llvm-svn: 266584
2016-04-18 01:34:20 +00:00
Rafael Espindola 5628ee7631 Simplify got handling.
Each getRelExpr is now expected to return the correct got expression
instead of having Writer patch it up with needsGot.

llvm-svn: 266466
2016-04-15 19:14:18 +00:00
Rafael Espindola 3151d89595 Simplify handling of size relocations. NFC.
llvm-svn: 266355
2016-04-14 18:39:44 +00:00
Rafael Espindola 22ef956a45 Change how we apply relocations.
With this patch we use the first scan over the relocations to remember
the information we found about them: will them be relaxed, will a plt be
used, etc.

With that the actual relocation application becomes much simpler. That
is particularly true for the interfaces in Target.h.

This unfortunately means that we now do two passes over relocations for
non SHF_ALLOC sections. I think this can be solved by factoring out the
code that scans a single relocation. It can then be used both as a scan
that record info and for a dedicated direct relocation of non SHF_ALLOC
sections.

I also think it is possible to reduce the number of enum values by
representing a target with just an OutputSection and an offset (which
can be from the start or end).

This should unblock adding features like relocation optimizations.

llvm-svn: 266158
2016-04-13 01:40:19 +00:00
Rafael Espindola 6f92e14ce2 Use DefinedSynthetic for _gp* symbols.
The test changes to put _gp* in the .got section matches what both bfd
and gold do.

llvm-svn: 266067
2016-04-12 13:26:51 +00:00
Rafael Espindola 666625b78c Pass a const pointer to getImplicitAddend. NFC.
llvm-svn: 265143
2016-04-01 14:36:09 +00:00
Simon Atanasyan 13f6da1d2c [ELF] Implement infrastructure for thunk code creation
Some targets might require creation of thunks. For example, MIPS targets
require stubs to call PIC code from non-PIC one. The patch implements
infrastructure for thunk code creation and provides support for MIPS
LA25 stubs. Any MIPS PIC code function is invoked with its address
in register $t9. So if we have a branch instruction from non-PIC code
to the PIC one we cannot make the jump directly and need to create a small
stub to save the target function address.
See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf

- In relocation scanning phase we ask target about thunk creation necessity
by calling `TagetInfo::needsThunk` method. The `InputSection` class
maintains list of Symbols requires thunk creation.

- Reassigning offsets performed for each input sections after relocation
scanning complete because position of each section might change due
thunk creation.

- The patch introduces new dedicated value for DefinedSynthetic symbols
DefinedSynthetic::SectionEnd. Synthetic symbol with that value always
points to the end of the corresponding output section. That allows to
escape updating synthetic symbols if output sections sizes changes after
relocation scanning due thunk creation.

- In the `InputSection::writeTo` method we write thunks after corresponding
input section. Each thunk is written by calling `TargetInfo::writeThunk` method.

- The patch supports the only type of thunk code for each target. For now,
it is enough.

Differential Revision: http://reviews.llvm.org/D17934

llvm-svn: 265059
2016-03-31 21:26:23 +00:00
Rafael Espindola 4e5ab42e21 Pass a const SymbolBody to needsGot. NFC.
llvm-svn: 265012
2016-03-31 13:38:28 +00:00
Rafael Espindola 287e100db2 No relocation needs bot SA and ZA.
Pass only one of them to relocateOne.

llvm-svn: 264866
2016-03-30 13:27:50 +00:00
Rafael Espindola da99df366d Fix handling of addends on i386.
Because of merge sections it is not sufficient to just add them while
applying a relocation.

llvm-svn: 264863
2016-03-30 12:40:38 +00:00
Rafael Espindola 163974dd33 Simplify AHL handling.
This simplifies a few things

* Read the value as early as possible, instead of passing a pointer to
  the location.
* Print the warning for missing pair close to where we find out it is
  missing.
* Don't pass the value to relocateOne.

llvm-svn: 264802
2016-03-29 23:05:59 +00:00
Rafael Espindola 5432287bad Make needsPlt a plain function instead of a template.
llvm-svn: 264267
2016-03-24 12:55:27 +00:00
Rafael Espindola 54bf9e1ca5 Don't pass SymbolBody to the relax* functions.
We already pass the symbol value.

llvm-svn: 263670
2016-03-16 23:01:56 +00:00
Rafael Espindola 89cc14fd46 Split relaxTls into one per relaxation type.
This reduces code duplication in each target.

llvm-svn: 263653
2016-03-16 19:03:58 +00:00
Rui Ueyama 9328b2cdde Use ELFT instead of ELFFile<ELFT>.
llvm-svn: 263510
2016-03-14 23:16:09 +00:00
George Rimar cbcda9e077 Remove dead code. NFC.
llvm-svn: 263433
2016-03-14 14:25:28 +00:00
Rafael Espindola 67d72c02bc Create a SymbolBody for locals.
pr26878 shows a case where locals have to be in the got.

llvm-svn: 263222
2016-03-11 12:06:30 +00:00
Rafael Espindola 1f04c44885 Delete isTlsDynRel.
It was a badly specified hack for when a tls relocation should be
propagated to the dynamic relocation table.

This replaces it with a not as bad hack of saying that a local dynamic
tls relocation is never preempted.

I will try to remove even that second hack in the next patch.

llvm-svn: 262955
2016-03-08 20:24:36 +00:00
George Rimar 7b8850f2bd [ELF] - Changed return type of Target::relaxTls()
Patch changes the return type of Target::relaxTls 
to size_t from unsigned. That is consistent with
its use from other code.

Change was reviewed http://reviews.llvm.org/D17882
and asked to commit separately from that patch above.

llvm-svn: 262794
2016-03-06 06:09:50 +00:00
George Rimar 98b060d228 [ELF] - Use the uint32_t instead of unsigned in Target class for relocations types
Patch changes all relocations types to be uint32_t and also 
fixes some dependent inconsistency in callers code.

Differential revision: http://reviews.llvm.org/D17882

llvm-svn: 262793
2016-03-06 06:01:07 +00:00
Rafael Espindola d405f4721c Refactor target independent code.
The rules for when we can relax tls relocations are target independent.
The only things that are target dependent are the relocation values.

llvm-svn: 262748
2016-03-04 21:37:09 +00:00
Rafael Espindola 1ea51d2718 Refactor duplicated code.
llvm-svn: 262720
2016-03-04 16:14:19 +00:00
Rafael Espindola e0df00b91f Rename elf2 to elf.
llvm-svn: 262159
2016-02-28 00:25:54 +00:00
Rafael Espindola 993f0273e3 Fix some confusion about what can be preempted.
For shared libraries we allow any weak undefined symbol to eventually be
resolved, even if we never see a definition in another .so. This matches
the behavior when handling other undefined symbols in a shared library.

For executables, we require seeing a definition in a .so or resolve it
to zero. This is also similar to how non weak symbols are handled.

llvm-svn: 262017
2016-02-26 14:27:47 +00:00
Rafael Espindola 795dc5a0fb Move target independent code out of x86_64 only path.
The logic for deciding if an undefined symbol should have the value of a
got entry is not target specific.

llvm-svn: 261760
2016-02-24 18:24:23 +00:00
Rafael Espindola f7ae359d2c Simplify. NFC.
llvm-svn: 261668
2016-02-23 18:53:29 +00:00
Rafael Espindola fb1533b326 Don't create copy relocs in shared libraries.
This fixes PR26699.

llvm-svn: 261576
2016-02-22 21:23:29 +00:00
Rafael Espindola 852860e920 make needsPlt a pure predicate.
llvm-svn: 260685
2016-02-12 15:47:37 +00:00
Adhemerval Zanella 74bcf03f87 [lld] [ELF/AArch64] Add support to some GD/LE/IS TLS relocations
This patch adds some TLS relocations and relaxations for AArch64.
Some Global-Dynamic relocation are handled by optimizing them to
Local-Exec (Initial-Exec is not yet supported). They are:

 - R_AARCH64_TLSDESC_ADR_PAGE21
 - R_AARCH64_TLSDESC_LD64_LO12_NC
 - R_AARCH64_TLSDESC_ADD_LO12_NC
 - R_AARCH64_TLSDESC_CALL

Also some Init-Exec is optimized to Local-Exec if possible. They are:

 - R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21
 - R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC

Finally some Local-Exec relocation are handled in relocateOne:

 - R_AARCH64_TLSLE_ADD_TPREL_HI12
 - R_AARCH64_TLSLE_ADD_TPREL_LO12_NC

This work is mainly for compiler bootstrap, where static binaries is
showing good progress (although shared object still lacking support
from both TLS aarch64 backend and some other issues).

llvm-svn: 260677
2016-02-12 13:43:03 +00:00
Rui Ueyama c1c282a04e ELF: Release Target at end of link().
Previously, Target held a value until a new value is assigned to the
variable. That was a benign leak -- that was not an unbounded leak
and didn't grab any resources except a small amount of memory. But
it is better to fix than leaving as is.

llvm-svn: 260592
2016-02-11 21:18:01 +00:00
George Rimar 2960c9867a [ELF] - Remove R_X86_64_GOTTPOFF from static relocation processing
R_X86_64_TPOFF64 is a dynamic relocation,
it should not appear in static relocation processing.
Patch fixes it.

Differential revision: http://reviews.llvm.org/D16880

llvm-svn: 260508
2016-02-11 11:14:46 +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
Simon Atanasyan 4b03451cac [ELF][MIPS] Replace needsMipsLocalGot function by canBePreempted
Symbol does not need an entry i the 'global' part of GOT if it cannot be
preempted. So canBePreempted fully satisfies us at least for now.

llvm-svn: 259779
2016-02-04 11:51:45 +00:00
Rui Ueyama 9398f86a2a Remove a parameter from Target::writePlt.
llvm-svn: 259158
2016-01-29 04:15:02 +00:00
Rui Ueyama 012eb783b3 ELF: Provide default implemenatations for simple functions.
llvm-svn: 259157
2016-01-29 04:05:09 +00:00
Rui Ueyama 57b676c546 Define stub functions instead of pure virtual functions.
To remove empty functions.

llvm-svn: 259155
2016-01-29 03:51:51 +00:00
Rui Ueyama 900e2d2578 ELF: Do not pass addresses that can be obtained using Out.
llvm-svn: 259154
2016-01-29 03:51:49 +00:00
Rui Ueyama 6251545683 Rename PltZeroEntrySize -> PltZeroSize.
This patch also fixes parameter name. They points to the beginning
of PLT or GOT tables, so GotAddr or PltAddr are better.)

llvm-svn: 259150
2016-01-29 03:00:32 +00:00
Rui Ueyama 69c30edb5e Add a comment.
llvm-svn: 259149
2016-01-29 03:00:30 +00:00
Rui Ueyama c516ae1719 ELF: Make Target's member function names shorter.
llvm-svn: 259147
2016-01-29 02:33:45 +00:00
Rui Ueyama 724d625c7a ELF: Remove accessors from Target.
These accessors do not provide values. We can simply make the variables public.

llvm-svn: 259141
2016-01-29 01:49:32 +00:00
Rui Ueyama 74b7df016f Remove unused variable.
llvm-svn: 259140
2016-01-29 01:49:29 +00:00
Rui Ueyama baf16512ea Rename isTlsOptimized -> canRelaxTls.
This function is a predicate that a given relocation can be relaxed.
The previous name implied that it returns true if a given relocation
has already been optimized away.

llvm-svn: 259128
2016-01-29 00:20:12 +00:00
George Rimar 237b218770 [ELF] - fix possible UB when dereferencing null
In InputSection.cpp it was possible to dereference null.
Had to change signature of relocateTlsOptimize to accept pointer instead of reference.

Differential revision: http://reviews.llvm.org/D16466

llvm-svn: 258508
2016-01-22 18:02:28 +00:00
Simon Atanasyan 56ab5f0289 [ELF][MIPS] Initial support of MIPS local GOT entries
Some MIPS relocation (for now R_MIPS_GOT16) requires creation of GOT
entries for symbol not included in the dynamic symbol table. They are
local symbols and non-local symbols with 'local' visibility. Local GOT
entries occupy continuous block between GOT header and regular GOT
entries.

The patch adds initial support for handling local GOT entries. The main
problem is allocating local GOT entries for local symbols. Such entries
should be initialized by high 16-bit of the symbol value. In ideal world
there should be no duplicated entries with the same values. But at the
moment of the `Writer::scanRelocs` call we do not know a value of the
symbol. In this patch we create new local GOT entry for each relocation
against local symbol, though we can exhaust GOT quickly. That needs to
be optimized later. When we calculate relocation we know a final symbol
value and request local GOT entry index. To do that we maintain map
between addresses and local GOT entry indexes. If we start to calculate
relocations in parallel we will have to serialize access to this map.

Differential Revision: http://reviews.llvm.org/D16324

llvm-svn: 258388
2016-01-21 05:33:23 +00:00
Simon Atanasyan 682aeea9de [ELF][MIPS] Ignore 'hint' relocations like R_MIPS_JALR in the `scanRelocs` method
MIPS ABI has relocations like R_MIPS_JALR which is just a hint for
linker to make some code optimization. Such relocations should not be
handled as a regular ones and lead to say dynamic relocation creation.

The patch introduces new virtual `Target::isHintReloc` method, overrides
it in the `MipsTargetInfo` class and calls it in the `Writer<ELFT>::scanRelocs`
method.

Differential Revision: http://reviews.llvm.org/D16193

llvm-svn: 257798
2016-01-14 20:42:09 +00:00
Rui Ueyama b705b10012 ELF: Remove dead code.
R_X86_64_PLT32 is handled in the same way as R_X86_64_PC32 by
relocateOne(), so this function does not seems to be needed.
Without this code, all tests still pass.

http://reviews.llvm.org/D15971

llvm-svn: 257203
2016-01-08 20:11:47 +00:00
Rui Ueyama 2b0edc2fdc Add a comment.
llvm-svn: 257140
2016-01-08 02:41:35 +00:00
Rui Ueyama 3a7c2f6f44 ELF: Simplify Target::isSizeReloc and add comments.
All non-trivial relocation decisions need explanations like this
to help readers understand not only how relocations are handled but
why they are handled these ways. This is a start.

llvm-svn: 257119
2016-01-08 00:13:23 +00:00
George Rimar a07ff66112 [ELF] - Implemented R_*_IRELATIVE relocations for x86, x64 targets.
This relocation is similar to R_*_RELATIVE except that the value used in this relocation is the program address returned by the function, which takes no arguments, at the address of
the result of the corresponding R_*_RELATIVE relocation as specified in the processor-specific ABI. The purpose of this relocation to avoid name lookup for locally defined STT_GNU_IFUNC symbols at load-time.

More info can be found in ifunc.txt from https://sites.google.com/site/x32abi/documents.

Differential revision: http://reviews.llvm.org/D15235

llvm-svn: 256144
2015-12-21 10:12:06 +00:00
George Rimar bfb7bf7429 [ELF] - R_386_GOTOFF relocation implemented.
R_386_GOTOFF is calculated as S + A - GOT, where:
S - Represents the value of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.
GOT - Represents the address of the global offset table.

Differential revision: http://reviews.llvm.org/D15383

llvm-svn: 256143
2015-12-21 10:00:12 +00:00
George Rimar 6f17e09307 [ELF] - implemented @indntpoff (x86) relocation and its optimization.
@indntpoff is similar to @gotntpoff, but for use in position dependent code. While @gotntpoff resolves to GOT slot address relative to the
start of the GOT in the movl or addl instructions, @indntpoff resolves to the
absolute GOT slot address. ("ELF Handling For Thread-Local Storage", Ulrich Drepper).

Differential revision: http://reviews.llvm.org/D15494

llvm-svn: 255884
2015-12-17 09:32:21 +00:00
Rui Ueyama 02dfd496b0 ELF: Rename relocNeedsCopy -> needsCopyRel
Just "copy" was a bit too ambiguous to say about copy relocations.

llvm-svn: 255866
2015-12-17 01:18:40 +00:00
George Rimar 48651489b3 [ELF] - R_X86_64_SIZE64/R_X86_64_SIZE32 relocations implemented.
R_X86_64_SIZE64/R_X86_64_SIZE32 relocations were introduced in 0.98v of "System V Application Binary Interface x86-64" (http://www.x86-64.org/documentation/abi.pdf).

Calculation for them is Z + A, where:
Z - Represents the size of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.

Differential revision: http://reviews.llvm.org/D15335

llvm-svn: 255332
2015-12-11 08:59:37 +00:00
George Rimar 25411f2558 [ELF] - Implemented @tlsgd optimization (GD->IE case, x64).
"Ulrich Drepper, ELF Handling For Thread-Local Storage" (5.5 x86-x64 linker optimizations, http://www.akkadia.org/drepper/tls.pdf) shows how GD can be optimized to IE.
This patch implements the optimization.

Differential revision: http://reviews.llvm.org/D15000

llvm-svn: 254713
2015-12-04 11:20:13 +00:00
Simon Atanasyan 09b3e3685f [ELF] MIPS paired R_MIPS_HI16/LO16 relocations support
Some MIPS relocations including `R_MIPS_HI16/R_MIPS_LO16` use combined
addends. Such addend is calculated using addends of both paired relocations.
Each `R_MIPS_HI16` relocation is paired with the next `R_MIPS_LO16`
relocation. ABI requires to compute such combined addend in case of REL
relocation record format only.

For details see p. 4-17 at
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf

This patch implements lookup of the next paired relocation suing new
`InputSectionBase::findPairedRelocLocation` method. The primary
disadvantage of this approach is that we put MIPS specific logic into
the common code. The next disadvantage is that we lookup `R_MIPS_LO16`
for each `R_MIPS_HI16` relocation, while in fact multiple `R_MIPS_HI16`
might be paired with the single `R_MIPS_LO16`. From the other side
this way allows us to keep `MipsTargetInfo` class stateless and implement
later relocation handling in parallel.

This patch does not support `R_MIPS_HI16/R_MIPS_LO16` relocations against
`_gp_disp` symbol. In that case the relocations use a special formula for
the calculation. That will be implemented later.

Differential Revision: http://reviews.llvm.org/D15112

llvm-svn: 254461
2015-12-01 21:24:45 +00:00
George Rimar b8bfd25239 [ELF] - Target interface simplification, getGotRefReloc() removed.
Removes Target::getGotRefReloc() method to simplify Target class a little.

Differential revision: http://reviews.llvm.org/D15107

llvm-svn: 254429
2015-12-01 17:52:40 +00:00
George Rimar 77b7779b48 Reapply r254098.
Fix is (OutputSections.cpp):
for (std::pair<const SymbolBody *, size_t> &I : Entries) {
 =>
for (std::pair<const SymbolBody *, unsigned> &I : Entries) {

llvm-svn: 254105
2015-11-25 22:15:01 +00:00
George Rimar dbb2f6188d Revert r254098 as it seems broke build bot.
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/3555

llvm-svn: 254103
2015-11-25 22:03:16 +00:00
George Rimar 6713cf8a52 [ELF] - Implemented optimizations for @tlsld and @tlsgd
Implements @tlsld (LD to LE) and @tlsgd (GD to LE) optimizations.
Patch does not implement the GD->IE case for @tlsgd.

Differential revision: http://reviews.llvm.org/D14870

llvm-svn: 254101
2015-11-25 21:46:05 +00:00
George Rimar 21c0a7131b [ELF] - Lazy relocations support for x86 target.
Patch implements lazy relocations for x86.
One of features of x86 is that executable files and shared object files have separate procedure linkage tables. So patch implements both cases.

Detailed information about instructions used can be found in http://docs.oracle.com/cd/E19620-01/805-3050/chapter6-1235/index.html (search: x86: Procedure Linkage Table).

Differential revision: http://reviews.llvm.org/D14955

llvm-svn: 254098
2015-11-25 21:37:59 +00:00
George Rimar d23970f778 [ELF/x86] Implemented R_386_TLS_LE_32, R_386_TLS_LE relocations.
This patch implements next relocations:
R_386_TLS_LE - Negative offset relative to static TLS (GNU version).
R_386_TLS_LE_32 - Offset relative to static TLS block.

These ones are created when using next code sequences:
* @tpoff - The operator must be used to compute an immediate value. The linker will report
an error if the referenced variable is not defined or it is not code for the executable
itself. No GOT entry is created in this case.
* @ntpoff Calculate the negative offset of the variable it is added to relative to the static TLS block.
The operator must be used to compute an immediate value. The linker will report
an error if the referenced variable is not defined or it is not code for the executable
itself. No GOT entry is created in this case.

Information was found in Ulrich Drepper, ELF Handling For Thread-Local Storage, http://www.akkadia.org/drepper/tls.pdf, (6.2, p76)

Differential revision: http://reviews.llvm.org/D14930

llvm-svn: 254090
2015-11-25 20:41:53 +00:00
George Rimar 1393477fd7 [ELF] - simplify Target interface, relocPointsToGot() removed.
https://docs.oracle.com/cd/E19683-01/817-3677/chapter6-26/index.html says:
R_386_GOTPC
Resembles R_386_PC32, except that it uses the address of the global offset table in its calculation. The symbol referenced in this relocation normally is _GLOBAL_OFFSET_TABLE_, which also instructs the link-editor to create the global offset table.

Currently _GLOBAL_OFFSET_TABLE_ has value == zero. And we use GOT address to calculate the relocation. This patch does not changes that. It just removes the method which is used only for x86. So it is close to non functional change.

Differential revision: http://reviews.llvm.org/D14993

llvm-svn: 254088
2015-11-25 20:20:31 +00:00
George Rimar 77d1cb1ddf [ELF2] - Optimization for R_X86_64_GOTTPOFF relocation.
R_X86_64_GOTTPOFF is not always requires GOT entries. Some relocations can be converted to local ones.

Differential revision: http://reviews.llvm.org/D14713

llvm-svn: 253966
2015-11-24 09:00:06 +00:00
Igor Kudrin 5d2bffdd57 [ELF/AArch64] Add support for R_AARCH64_ADR_GOT_PAGE and R_AARCH64_LD64_GOT_LO12_NC.
With these relocations, it is now possible to build a simple "hello world"
program for AArch64 Debian.

Differential revision: http://reviews.llvm.org/D14917

llvm-svn: 253957
2015-11-24 06:48:31 +00:00
Igor Kudrin e7ad0937bb [ELF2] getPLTRefReloc() -> getPltRefReloc().
llvm-svn: 253351
2015-11-17 17:47:53 +00:00
Igor Kudrin 351b41de4e [ELF2] Remove target specific code from GotPltSection.
The content of reserved entries of the .got.plt section is target specific.

In particular, on x86_64 the zero entry holds the address of the .dynamic section,
but on AArch64 the same info is stored in the zero entry of the .got section.

Differential revision: http://reviews.llvm.org/D14703

llvm-svn: 253239
2015-11-16 17:44:08 +00:00
George Rimar 687138c7d1 [ELF2] - Implemented R_X86_64_GOTTPOFF relocation
Generates single GOT entry, R_X86_64_TPOFF64 is added to RelaDyn.

Differential revision: http://reviews.llvm.org/D14621

llvm-svn: 253049
2015-11-13 16:28:53 +00:00
Michael J. Spencer ecd7f377dd [elf2] get{Local,Global}DynamicReloc -> is{LocalGlobal}DynamicReloc.
llvm-svn: 252982
2015-11-13 00:32:58 +00:00
Michael J. Spencer 627ae703b5 [elf2] Implement global dynamic tls.
llvm-svn: 252979
2015-11-13 00:28:34 +00:00
Michael J. Spencer 1e22561a57 [elf2] Add support for R_X86_64_TLSLD.
leaq symbol@tlsld(%rip), %rdi
call __tls_get_addr@plt

symbol@tlsld (R_X86_64_TLSLD) instructs the linker to generate a tls_index entry (two GOT slots) in the GOT for the entire module (shared object or executable) with an offset of 0. The symbol for this GOT entry doesn't matter (as long as it's either local to the module or null), and gold doesn't put a symbol in the dynamic R_X86_64_DTPMOD64 relocation for the GOT entry.

All other platforms defined in http://www.akkadia.org/drepper/tls.pdf except for Itanium use a similar model where global and local dynamic GOT entries take up 2 contiguous GOT slots, so we can handle this in a unified manner if we don't care about Itanium.

While scanning relocations we need to identify local dynamic relocations and generate a single tls_index entry in the GOT for the module and store the address of it somewhere so we can later statically resolve the offset for R_X86_64_TLSLD relocations. We also need to generate a R_X86_64_DTPMOD64 relocation in the RelaDyn relocation section.

This implementation is a bit hacky. It side steps the issue of GotSection and RelocationSection only handling SymbolBody entries by relying on a specific relocation type. The alternative to this seemed to be completely rewriting how GotSection and RelocationSection work, or using a different hacky signaling method.

llvm-svn: 252682
2015-11-11 01:00:24 +00:00
Igor Kudrin f6f45476f5 [ELF2] Remove Writer::getVAStart, use TargetInfo::getVAStart instead.
llvm-svn: 252593
2015-11-10 08:39:27 +00:00
Igor Kudrin 15cd9ffd1e [ELF2] Add GOT section for MIPS target.
This patch implements R_MIPS_GOT16 relocation for global symbols in order to
generate some entries in GOT. Only reserved and global entries are supported
for now. For the detailed description about GOT in MIPS, see "Global Offset
Table" in Chapter 5 in the followin document:
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf

In addition, the platform specific symbol "_gp" is added, see "Global Data
Symbols" in Chapter 6 in the aforementioned document.

Differential revision: http://reviews.llvm.org/D14211

llvm-svn: 252275
2015-11-06 07:43:03 +00:00
George Rimar bc590feb2b [ELF2] R_X86_64_COPY relocation implemented
Differential revision: http://reviews.llvm.org/D14090.

llvm-svn: 251526
2015-10-28 16:48:58 +00:00
Rui Ueyama 96f0e0bfc9 ELF2: Improve Target::relocateOne().
relocateOne is a function to apply a relocation. Previously, that
function took a pointer to Elf_Rel or Elf_Rela in addition to other
information that can be derived from the relocation entry. This patch
simplifies the parameter list. The new parameters, P or SA, are used
in the ELF spec to describe each relocation. These names make
relocateOne look like a mechanical, direct translation of the ELF spec.

llvm-svn: 251090
2015-10-23 02:40:46 +00:00
George Rimar 648a2c37fb [ELF2] - Lazy relocation support for x86_64.
Target has supportsLazyRelocations() method which can switch lazy relocations on/off (currently all targets are OFF except x64 which is ON). So no any other targets are affected now.

Differential Revision: http://reviews.llvm.org/D13856?id=37726

llvm-svn: 250808
2015-10-20 08:54:27 +00:00
Hal Finkel 6f97c2bc00 [ELF2] getLocalRelTarget should handle R_PPC64_TOC directly
R_PPC64_TOC does not have an associated symbol, but does have a non-zero VA
that target-specific code must compute using some non-trivial rule. We
handled this as a special case in PPC64TargetInfo::relocateOne, where
we knew to write this special address, but that did not work when creating shared
libraries. The special TOC address needs to be the subject of a
R_PPC64_RELATIVE relocation, and so we also need to know how to encode this
special address in the addend of that relocation.

Thus, some target-specific logic is necessary when creating R_PPC64_RELATIVE as
well. To solve this problem, we teach getLocalRelTarget to handle R_PPC64_TOC
as a special case. This allows us to remove the special case in
PPC64TargetInfo::relocateOne (simplifying code there), and naturally allows the
existing logic to do the right thing when creating associated R_PPC64_RELATIVE
relocations for shared libraries.

llvm-svn: 250555
2015-10-16 21:55:40 +00:00
Hal Finkel 736c741752 [ELF2] Set a target-specific VAStart for PPC64
After some additional post-commit (post-revert) discussion and research, this
reverts, in part, r250205, so the ABI-recommended starting address can be used
on PPC64 (as is done by other linkers).

Also, this addresses the FIXME in ELF/Writer.cpp by making VAStart a
target-dependent property.

llvm-svn: 250378
2015-10-15 07:49:07 +00:00
Rui Ueyama efc23de4dd ELF2: Move Target concrete classes from .h to .cpp.
llvm-svn: 250330
2015-10-14 21:30:32 +00:00
Rafael Espindola 227556e1c7 Add support for a R_X86_64_32 referring to a plt.
This can show up with a non-PIC .o being linked into an executable that uses
shared libraries.

llvm-svn: 250300
2015-10-14 16:15:46 +00:00
Simon Atanasyan 9c2d788dda [ELF2][mips] Support both big and little endian MIPS 32-bit targets
- Make the `MipsTargetInfo` template class with `ELFType` argument. Use
  the argument to select an appropriate relocation type and read/write
  routines.
- Add template function `add32` to add-and-write relocation value in
  both big and little endian cases. Keep the `add32le` to reduce code
  changes.

Differential Revision: http://reviews.llvm.org/D13723

llvm-svn: 250297
2015-10-14 14:24:46 +00:00
Hal Finkel d962ef0bf8 Revert: "Re: [lld] r249752 - Revert: r249728 - Roll back r249726 and r249723 because they broke buildbots."
This has turned out to be unnecessary, and while some ability to set VAStart
will be needed at some point, this is not clearly the right direction.

llvm-svn: 250205
2015-10-13 18:50:28 +00:00
Rui Ueyama c58656c7c0 Revert r250169: "This patch implements basic variant of lazy loading for x86_x64 and for X86 targets."
With this patch LLD is not able to self-host on x86-64 Linux.

llvm-svn: 250182
2015-10-13 16:59:30 +00:00
George Rimar 9fd8fcb5a4 This patch implements basic variant of lazy loading for x86_x64 and for X86 targets.
What was done:
1) .got.plt section is created for functions that requires PLT. .got.plt has 3 predefined empty entries now that are required for dynamic linker.
Also other new items created are configured to have correct jump to PLT[N].
2) PLT section now has PLT[0] entry, also others ones are configured to support PLT->GOT(.got.plt) calls.
3) Implemented .rel[a].plt sections (based on patch http://reviews.llvm.org/D13569).
4) Fixed plt relocations types (based on patch http://reviews.llvm.org/D13589).

NOTES:
The .plt.got zero entry is still empty now. According to ELF specification it should hold the address of the dynamic structure, referenced with the symbol
_DYNAMIC. The _DYNAMIC entry points to the .dynamic section which contains information used by the ELF interpreter to setup the binary.

Differential Revision: http://reviews.llvm.org/D13651

llvm-svn: 250169
2015-10-13 16:09:55 +00:00
Rui Ueyama 9100439391 ELF2: Move createTarget to Target.cpp.
Now all Target<Arch> classes are used only in Target.cpp.
We can put them in an anonymous namespace. In order to avoid
merge conflict with other people's patches, I'll do that later.

llvm-svn: 250168
2015-10-13 16:08:15 +00:00
Rui Ueyama e7e3348aa3 ELF2: Remove dead code.
This code is completely a stub. We can resurrect when we start working on ARM.

llvm-svn: 250167
2015-10-13 16:03:39 +00:00
Hal Finkel 87bbd5ffd4 [ELF2] Allow PPC64 to add the TOC-restore after .plt-based relocations
Under the PPC64 ELF ABI, functions that might call into other modules (and,
thus, need to load a different TOC base value into %r2), need to restore the
old value after the call. The old value is saved by the .plt code, and the
caller only needs to include a nop instruction after the call, which the linker
will transform into a TOC restore if necessary.

In order to do this the relocation handler needs two things:

 1. It needs to know whether the call instruction it is modifying is targeting
    a .plt stub that will load a new TOC base value (necessitating a restore after
    the call).

 2. It needs to know where the buffer ends, so that it does not accidentally
    run off the end of the buffer when looking for the 'nop' instruction after the
    call.

Given these two pieces of information, we can insert the restore instruction in
place of the following nop when necessary.

llvm-svn: 250110
2015-10-12 21:19:18 +00:00
Hal Finkel be0823dcc4 [ELF2] Implement PPC64TargetInfo::isRelRelative
This is essentially pattern-matching against the x86 target, and generates the
analogous PPC64 relocation.

llvm-svn: 250102
2015-10-12 20:58:52 +00:00
Rui Ueyama 0cef68913e ELF2: Handle default entry name in the driver.
llvm-svn: 250048
2015-10-12 15:23:54 +00:00
Hal Finkel e3c2626aa4 [ELF2] Make the system page size a target-dependent property
The required page alignment is different on different targets. On PowerPC, for
example, we need 64K pages (the loader won't set different permissions on a
finer granularity than that). I've set the existing targets to what I believe
to be the correct values, and have updated the regression tests accordingly.

llvm-svn: 249760
2015-10-08 22:23:54 +00:00
Hal Finkel 6c2a3b8368 [ELF2] Make the .plt entry size target dependent
The size of a .plt entry is different on different targets (it is,
specifically, much larger than 8 on all PPC ABIs). There is no functional
change here (later patches to create .plt entries for PPC64 will depend on this
change).

llvm-svn: 249756
2015-10-08 21:51:31 +00:00
Hal Finkel 4729064a1c Revert: r249728 - Roll back r249726 and r249723 because they broke buildbots.
Reapply r249726 (and r249723), hopefully with the correct test fixups this time.

Original commit message:

Address a FIXME in ELF/Writer.cpp: Make VAStart a target-dependent property.
I've set the values for the existing targets to what I believe to be the
correct values, and updated the regression tests accordingly.

llvm-svn: 249752
2015-10-08 21:25:04 +00:00
Rui Ueyama af21d92320 ELF2: Do not pass GotVA because it's accessible as Out<ELFT>::Got->getVA().
llvm-svn: 249729
2015-10-08 20:06:07 +00:00
Rui Ueyama 7114f0597b Roll back r249726 and r249723 because they broke buildbots.
llvm-svn: 249728
2015-10-08 20:00:02 +00:00
Hal Finkel eb84ce8bd1 [ELF2] Make VAStart a target-dependent property
Address a FIXME in ELF/Writer.cpp: Make VAStart a target-dependent property.
I've set the values for the existing targets to what I believe to be the
correct values, and updated the regression tests accordingly.

llvm-svn: 249723
2015-10-08 19:36:39 +00:00
Rafael Espindola ae24400424 Create R_X86_64_RELATIVE when needed.
The dynamic relocation code needs refactoring, but it is probably better
to do it with this test passing.

llvm-svn: 249340
2015-10-05 19:30:12 +00:00
Rafael Espindola 3ef3a4c9ff Start adding support for static programs using dynamic libraries.
This is just enough for a hello world using a dynamic glibc.

llvm-svn: 248854
2015-09-29 23:22:16 +00:00
Rafael Espindola 8acb95c7ab Add support for R_386_GOT32.
llvm-svn: 248799
2015-09-29 14:42:37 +00:00
Rafael Espindola 6d7fcdb518 Add R_386_GOTPC support.
llvm-svn: 248793
2015-09-29 13:36:32 +00:00
Simon Atanasyan 49829a1bfe [ELF2] Add initial MIPS support
Besides a trivial MIPS support the patch introduces new TargetInfo class
member getDefaultEntry() to override default name of the entry symbol.
MIPS uses __start for that.

Differential Revision:  http://reviews.llvm.org/D13227

llvm-svn: 248779
2015-09-29 05:34:03 +00:00
Davide Italiano cde9336717 [ELF2] Add initial AArch64 support.
Differential Revision:	http://reviews.llvm.org/D13167

llvm-svn: 248641
2015-09-26 00:32:04 +00:00
Rafael Espindola 7f07442bb6 Move the last remaining hard coded relocations to Target.
Unfortunately the i386 and x86_64 relocation have the same numerical value
and it is a probably a bit much to add got support for another architecture
just to test this.

llvm-svn: 248326
2015-09-22 21:35:51 +00:00
Rafael Espindola 1d6063e804 Stub out ARM and PPC targets so that we can use a switch to create them.
llvm-svn: 248324
2015-09-22 21:24:52 +00:00
Rafael Espindola c40108858d Move relocation processing to Target.
I will add a couple of ppc64 relocs in the next patches.

llvm-svn: 248319
2015-09-22 20:54:08 +00:00
Rafael Espindola 01205f79a4 Start adding target abstractions.
This is just enough to get PLT working on 32 bit x86.

The idea behind using a virtual interface is that it should be easy to
convert any of the functions to template parameters if any turns out to be
performance critical.

llvm-svn: 248308
2015-09-22 18:19:46 +00:00