Commit Graph

304 Commits

Author SHA1 Message Date
Rafael Espindola
b5506e6baf Rename --icf-data and add a corresponding flag for functions.
When we have --icf=safe we should be able to define --icf=all as a
shorthand for --icf=safe --ignore-function-address-equality.

For now --ignore-function-address-equality is used only to control
access to non preemptable symbols in shared libraries.

llvm-svn: 322152
2018-01-10 01:37:36 +00:00
Rafael Espindola
4b6833332b Rewrite our relocation processing.
This splits relocation processing in two steps.

First, analyze what needs to be done at the relocation spot. This can
be a constant (non preemptible symbol, relative got reference, etc) or
require a dynamic relocation. At this step we also consider creating
copy relocations.

Once that is done we decide if we need a got or a plt entry.

The code is simpler IMHO. For example:

- There is a single call to isPicRel since the logic is not split
  among adjustExpr and the caller.
- R_MIPS_GOTREL is simple to handle now.
- The tracking of what is preemptible or not is much simpler now.

This also fixes a regression with symbols being both in a got and copy
relocated. They had regressed in r268668 and r268149.

The other test changes are because of error messages changes or the
order of two relocations in the output.

llvm-svn: 322047
2018-01-09 00:13:54 +00:00
Rafael Espindola
d1bd95cf73 Move scanReloc to an auxiliary function.
The body of the in scanRelocs is fairly big. This moves it to its own
function.

It is not a big readability win by itself, but should help further
refactoring.

llvm-svn: 322035
2018-01-08 22:20:44 +00:00
Rafael Espindola
8d13b213d4 Simplify handling of size relocations.
This is possible now that getSize is not a template.

llvm-svn: 321900
2018-01-05 21:41:17 +00:00
Rafael Espindola
73584cb587 Centralize Config->IsRela handling.
This merges the two places were we check Config->IsRela to decide how
to write a relocation addend.

llvm-svn: 321889
2018-01-05 20:08:38 +00:00
Rafael Espindola
a3ce1fdaba Inline a function that is only called once. NFC.
llvm-svn: 321780
2018-01-04 01:33:41 +00:00
Rafael Espindola
bba410668a Use references for a few arguments that are never null.
llvm-svn: 321772
2018-01-03 23:26:20 +00:00
Rafael Espindola
9cded98ad6 Mention symbol name in error message.
llvm-svn: 321769
2018-01-03 22:55:46 +00:00
Rafael Espindola
7c99c14722 Use getLocation to improve error message.
llvm-svn: 321768
2018-01-03 22:44:58 +00:00
Rafael Espindola
7137b8c298 Update code as this also handles GOT relocations.
llvm-svn: 321738
2018-01-03 16:54:18 +00:00
Rafael Espindola
49422f341a Use a switch. NFC.
llvm-svn: 321737
2018-01-03 16:52:15 +00:00
Rafael Espindola
cc333d7400 Refactor duplicated expression.
llvm-svn: 321736
2018-01-03 16:38:46 +00:00
Rafael Espindola
6e102b2fc6 Use a swtich. NFC.
llvm-svn: 321734
2018-01-03 16:29:43 +00:00
Rafael Espindola
28aa6e2bc5 Simplify mips gprel handling.
We normally add checks on the architecture independent Expr instead of
on the architecture dependent relocation type.

llvm-svn: 321733
2018-01-03 16:16:05 +00:00
Rafael Espindola
b5153ef7e8 Don't assume that size relocations are always constant.
llvm-svn: 321688
2018-01-03 03:58:58 +00:00
Rafael Espindola
4b2350d79b Produce relocations with weak undef if the section is RW.
If a section is RW there is no reason to drop a relocation with a weak
undefined symbol.

llvm-svn: 321684
2018-01-03 01:24:58 +00:00
Rafael Espindola
465e7c94ed Allow copy relocation with -z notext.
This makes adjustExpr a bit simpler too IMHO.

It seems that some of the complication around relocation processing
is that we are trying to create copy relocations too early. It seems
we could handle a few simple cases first and continue.

llvm-svn: 321507
2017-12-28 00:23:49 +00:00
Rafael Espindola
e2e070c6c4 Don't try to preempt protected symbols with -z notext.
I will send a followup patch removing the FIXME this patch adds.

llvm-svn: 321499
2017-12-27 20:53:13 +00:00
George Rimar
a0ab8d7a58 [ELF] - Allow relocation to a weak undefined symbol when -z notext is given.
Previously we failed to resolve them when produced executables:
"relocation R_X86_64_32 cannot be used against shared object; recompile with -fPIC"

Patch fixes it so that we resolve them to 0 for executables. 
And for -shared case we still should produce the relocation.

This finishes fixing PR35720.

DIfferential revision: https://reviews.llvm.org/D41551

llvm-svn: 321473
2017-12-27 07:29:55 +00:00
Rafael Espindola
a9c490b71d Allow relocations in rw sections to create plt entries.
If a relocation cannot be implemented by the dynamic linker and the
section is rw, allow creating a plt entry to use as the function
address as if the section was ro.

This matches bfd and gold. It also matches our behavior with -z
notext.

llvm-svn: 321430
2017-12-24 19:02:10 +00:00
Rafael Espindola
9a84f6b954 Detemplate reportDuplicate.
We normally avoid "switch (Config->EKind)", but in this case I think
it is worth it.

It is only executed when there is an error and it allows detemplating
a lot of code.

llvm-svn: 321404
2017-12-23 17:21:39 +00:00
George Rimar
3bdf6baa25 [ELF] - Allow using PLT relocations when "-z notext" is given.
This is part of PR35720.

Currently LLD allows dynamic relocations against text when -z notext is given.
Though for non-PIC relocations like R_X86_64_PC32 that does not work,
we produce "relocation R_X86_64_PC32 cannot be used against shared object;"
error because they may overflow in runtime.

Solution implemented is to use PLT for them.

Differential revision: https://reviews.llvm.org/D41541

llvm-svn: 321400
2017-12-23 09:00:37 +00:00
Rafael Espindola
a973cc2282 Call isStaticLinkTimeConstant only once per relocation.
It is a pretty expensive function. Some of the speedups:

clang: 1.92%
chrome: 1.15%
linux-kernel: 1.40%
llvm-svn: 321311
2017-12-21 21:45:35 +00:00
Rafael Espindola
a32ddc4639 Use a reference for the shared symbol file.
Every shared symbol has a file, so we can use a reference.

llvm-svn: 321187
2017-12-20 16:28:19 +00:00
Rafael Espindola
4c74feffd4 Don't write preemptible symbol values to the .got.
It is not necessary and matches what bfd and gold do.

This was a regression from r315658.

llvm-svn: 321023
2017-12-18 20:35:15 +00:00
Rafael Espindola
87e0deaea7 Move RelaPlt and RelaIplt to InX. NFC.
llvm-svn: 320327
2017-12-10 20:07:03 +00:00
Rafael Espindola
58946cdb08 Move RelaDyn to InX. NFC.
llvm-svn: 320324
2017-12-10 19:44:42 +00:00
Rafael Espindola
d26b52fd34 Remove some includes from InputFiles.h.
They were not used in InputFiles.h and it was getting too easy to add
circular includes.

llvm-svn: 320256
2017-12-09 16:56:18 +00:00
Rafael Espindola
91fac59a81 Add a call to std::vector::reserve.
This reduces total allocations when linking clang fsds from 263.21MB
to 174.62MB.

This also has some very nice speed improvements on some
benchmarks. Chromium and clang fsds link 6% faster.

llvm-svn: 319976
2017-12-06 22:32:19 +00:00
Rafael Espindola
a834b529c3 Fix a crash.
This is a constructed testcase I noticed while working on another
patch.

llvm-svn: 319874
2017-12-06 02:53:43 +00:00
Rafael Espindola
dfebd3601d Use Symbol::File directly.
We are already paying the cost of storing a InputFile in every
Symbol, so use it uniformly.

llvm-svn: 319378
2017-11-29 22:47:35 +00:00
Rui Ueyama
2017d52b54 Move Memory.{h,cpp} to Common.
Differential Revision: https://reviews.llvm.org/D40571

llvm-svn: 319221
2017-11-28 20:39:17 +00:00
Rafael Espindola
1d4b3023dc Bring back r319008.
This includes a fix to mark copy reloc aliases as used.

Original message:

[ELF] Do not keep symbols if they referenced only from discarded sections.

This patch also ensures that in case of "--as-needed" is used,
DT_NEEDED entries are not created if they are required only by
these eliminated symbols.

llvm-svn: 319215
2017-11-28 20:17:58 +00:00
Alexander Richardson
f463042312 [ELF][MIPS] Fix crash in LLD when linking code that needs PIC thunks
Summary:
The bug triggers when the following conditions are met:
    - A thunk is created in a given input section S
    - A linker script is specified
    - There is at least one matcher in the linker script .text section output
      that does not match any of the sections in the input files, before the matcher
      that matches section S.

The issue was found when linking the FreeBSD kernel for MIPS when built
with -fPIC. Patch by Alfredo Mazzinghi.

Reviewers: ruiu, psmith, atanasyan

Reviewed By: ruiu

Subscribers: peter.smith, emaste, sdardis, krytarowski, llvm-commits

Differential Revision: https://reviews.llvm.org/D40174

llvm-svn: 318653
2017-11-20 15:37:19 +00:00
Peter Smith
a2db4349d5 [ELF] Fix typo in comment for getISDThunkSec [NFC]
The ISR in the comment should read ISD for InputSectionDescription. The use
of ISR (InputSectionRange) was from the original implementation that did not
use the sections from InputSectionDescription directly.

llvm-svn: 317469
2017-11-06 10:36:18 +00:00
Peter Collingbourne
e9a9e0a1e7 ELF: Merge DefinedRegular and Defined.
Now that DefinedRegular is the only remaining derived class of
Defined, we can merge the two classes.

Differential Revision: https://reviews.llvm.org/D39667

llvm-svn: 317448
2017-11-06 04:35:31 +00:00
Rui Ueyama
48882249dd Rename Body -> Sym.
This patch is mechanically created by

  sed -i -e s/Body/Sym/g lld/ELF/*.{cpp,h}

and clang-format-diff.

llvm-svn: 317392
2017-11-04 00:31:04 +00:00
Rui Ueyama
f52496e1e0 Rename SymbolBody -> Symbol
Now that we have only SymbolBody as the symbol class. So, "SymbolBody"
is a bit strange name now. This is a mechanical change generated by

  perl -i -pe s/SymbolBody/Symbol/g $(git grep -l SymbolBody lld/ELF lld/COFF)

nd clang-format-diff.

Differential Revision: https://reviews.llvm.org/D39459

llvm-svn: 317370
2017-11-03 21:21:47 +00:00
George Rimar
82f0c42dad [ELF] - Teach LLD to report line numbers for data symbols.
This is PR34826.

Currently LLD is unable to report line number when reporting
duplicate declaration of some variable.

That happens because for extracting line information we always use
.debug_line section content which describes mapping from machine
instructions to source file locations, what does not help for
variables as does not describe them.

In this patch I am taking the approproate information about
variables locations from the .debug_info section.

Differential revision: https://reviews.llvm.org/D38721

llvm-svn: 317080
2017-11-01 07:42:38 +00:00
Rui Ueyama
f1f00841d9 Merge SymbolBody and Symbol into one class, SymbolBody.
SymbolBody and Symbol were separated classes due to a historical reason.
Symbol used to be a pointer to a SymbolBody, and the relationship
between Symbol and SymbolBody was n:1.

r2681780 changed that. Since that patch, SymbolBody and Symbol are
allocated next to each other to improve memory locality, and they have
1:1 relationship now. So, the separation of Symbol and SymbolBody no
longer makes sense.

This patch merges them into one class. In order to avoid updating too
many places, I chose SymbolBody as a unified name. I'll rename it Symbol
in a follow-up patch.

Differential Revision: https://reviews.llvm.org/D39406

llvm-svn: 317006
2017-10-31 16:07:41 +00:00
Rafael Espindola
566dbdc2fd Skip abs symbols when handling copy reloc aliases.
Since we now only check st_value, we have to consider the case where
the section index is special.

llvm-svn: 316928
2017-10-30 17:26:12 +00:00
Rui Ueyama
bd730e3ca7 Reduce sizeof(Symbol) from 104 bytes to 88 bytes.
Finding aliases for shared symbols doesn't need st_shndx because
we can just compare st_value.

llvm-svn: 316848
2017-10-28 22:18:17 +00:00
Rui Ueyama
7f9694a42d Pass symbol attributes instead of ElfSym to Shared symbol ctor.
This change allows us to use less templates for Shared symbol and
the functions that deals with shared symbols.

llvm-svn: 316841
2017-10-28 20:15:56 +00:00
Peter Smith
6c9df3fce5 [ELF] Add support for multiple passes to createThunks()
This change allows Thunks to be added on multiple passes. To do this we must
merge only the thunks added in each pass, and deal with thunks that have
drifted out of range of their callers.

A thunk may end out of range of its caller if enough thunks are added in
between the caller and the thunk. To handle this we create another thunk.

Differential Revision: https://reviews.llvm.org/D34692

llvm-svn: 316754
2017-10-27 09:07:10 +00:00
Peter Smith
75030b6d56 [ELF] Introduce range extension thunks for ARM
This change adds initial support for range extension thunks. All thunks must
be created within the first pass so some corner cases are not supported. A
follow up patch will add support for multiple passes.

With this change the existing tests arm-branch-error.s and
arm-thumb-branch-error.s now no longer fail with an out of range branch.
These have been renamed and tests added for the range extension thunk.

Differential Revision: https://reviews.llvm.org/D34691

llvm-svn: 316752
2017-10-27 09:04:11 +00:00
Peter Smith
f0c70f8d34 [ELF] Pre-create ThunkSections at Target specific intervals
When an OutputSection is larger than the branch range for a Target we
need to place thunks such that they are always in range of their caller,
and sufficiently spaced to maximise the number of callers that can use
the thunk. We use the simple heuristic of placing the
ThunkSection at intervals corresponding to a target specific branch range.
If the OutputSection is small we put the thunks at the end of the executable
sections.

Differential Revision: https://reviews.llvm.org/D34689

llvm-svn: 316751
2017-10-27 08:58:28 +00:00
Peter Smith
4a8e11595c [ELF] Record created ThunkSections in InputSectionDescription [NFC].
Instead of maintaining a map of the std::vector to ThunkSections, record the
ThunkSections directly in InputSectionDescription.

Differential Revision: https://reviews.llvm.org/D37743

llvm-svn: 316750
2017-10-27 08:56:20 +00:00
Rui Ueyama
d6b7a390d8 De-template elf::getObjMsg. NFC.
llvm-svn: 316732
2017-10-27 03:13:54 +00:00
Bob Haarman
b8a59c8aa5 [lld] unified COFF and ELF error handling on new Common/ErrorHandler
Summary:
The COFF linker and the ELF linker have long had similar but separate
Error.h and Error.cpp files to implement error handling. This change
introduces new error handling code in Common/ErrorHandler.h, changes the
COFF and ELF linkers to use it, and removes the old, separate
implementations.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: smeenai, jyknight, emaste, sdardis, nemanjai, nhaehnle, mgorny, javed.absar, kbarton, fedor.sergeev, llvm-commits

Differential Revision: https://reviews.llvm.org/D39259

llvm-svn: 316624
2017-10-25 22:28:38 +00:00
Simon Atanasyan
38f7d433ef [mips] Provide more detailed comment. NFC
llvm-svn: 316003
2017-10-17 14:39:03 +00:00