Commit Graph

1463 Commits

Author SHA1 Message Date
Fangrui Song 121078bee7 [ELF] PowerOpen ABI -> Power Architecture 64-bit v2 ABI. NFC
Reviewers: sfertile, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D46904

llvm-svn: 332572
2018-05-17 05:34:29 +00:00
Han Shen b56030ee9e [lld] Mitigate relocation overflow [part 1 of 2].
This CL places .dynsym and .dynstr at the beginning of SHF_ALLOC
sections. We do this to mitigate the possibility that huge .dynsym and
.dynstr sections placed between ro-data and text sections cause
relocation overflow.

Differential Revision: https://reviews.llvm.org/D45788

llvm-svn: 332374
2018-05-15 17:02:35 +00:00
George Rimar 4c9ae67bb7 [ELF] - Revert of: r332038, r332054, r332060, r332061, r332062, r332063
This reverts "Mitigate relocation overflow [part 1 of 2]." and the following commits which
were trying to fix the bots.

At the moment of r332082, bots are still failing and we need to find the reason of test case breakages first of all.
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/17042/steps/test/logs/stdio
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/29845/steps/test/logs/stdio

llvm-svn: 332085
2018-05-11 08:11:25 +00:00
Han Shen 6c0881c3cd Mitigate relocation overflow [part 1 of 2].
This CL is to mitigate R_X86_64_PC32 relocation overflow problems for huge binaries that has near 4G allocated sections.

By examining those binaries, there're 2 issues contributes to the problem:
1). huge ".dynsym" and ".dynstr" stands in the way between .rodata and .text
2). _init_array_start/end are placed at 0 if no ".init_array" presents, this causes .text relocation against them become more prone to overflow.

This CL addresses 1st problem (the 2nd will be addressed in another CL.) by assigning a smaller sortrank to .dynsym and .dynstr thus they no longer stand in between.

llvm-svn: 332038
2018-05-10 20:44:42 +00:00
Ed Maste 6556aa6848 [ELF] Omit PT_NOTE for SHT_NOTE without SHF_ALLOC
A non-alloc note section should not have a PT_NOTE program header.

Found while linking ghc (Haskell compiler) with lld on FreeBSD.
ghc emits a .debug-ghc-link-info note section (as the name suggests, it
contains link information) as a SHT_NOTE section without SHF_ALLOC set.

For this case ld.bfd does not emit a PT_NOTE segment for the
.debug-ghc-link-info section.  lld previously emitted a PT_NOTE with
p_vaddr = 0 and FreeBSD's rtld segfaulted when trying to parse a note at
address 0.

llvm.org/pr37361

Differential Revision:	https://reviews.llvm.org/D46623

llvm-svn: 331973
2018-05-10 11:12:18 +00:00
Sriraman Tallam be01d2e3de New option -z keep-text-section-prefix to keep text sections with prefixes separate.
Separate output sections for selected text section prefixes to enable TLB optimizations and for readablilty.

Differential Revision: https://reviews.llvm.org/D45841

llvm-svn: 331823
2018-05-08 23:19:50 +00:00
Zaara Syeda f61b0733a8 [PPC64] Remove support for ELF V1 ABI in LLD
The current support for V1 ABI in LLD is incomplete.
This patch removes V1 ABI support and changes the default behavior to V2 ABI,
issuing an error when using the V1 ABI. It also updates the testcases to V2
and removes any V1 specific tests.

Differential Revision: https://reviews.llvm.org/D46316

llvm-svn: 331529
2018-05-04 15:09:49 +00:00
Fangrui Song 1f3e2b2966 [ELF] Fix typo. NFC
llvm-svn: 331018
2018-04-27 05:50:40 +00:00
Rafael Espindola ab0cce5f1f Replace SharedSymbols with Defined when creating copy relocations.
This is slightly simpler to read IMHO. Now if a symbol has a position
in the file, it is Defined.

The main motivation is that with this a SharedSymbol doesn't need a
section, which reduces the size of SymbolUnion.

With this the peak allocation when linking chromium goes from 568.1 to
564.2 MB.

llvm-svn: 330966
2018-04-26 17:58:58 +00:00
George Rimar de83cbf37e [ELF] - Never use std::sort.
It turns out we should not use the std::sort anymore.
r327219 added a new wrapper llvm::sort (D39245).
When EXPENSIVE_CHECKS is defined, it shuffles the
input container and that helps to find non-deterministic
ordering.

Patch changes code to use llvm::sort and std::stable_sort
instead of std::sort

Differential revision: https://reviews.llvm.org/D45969

llvm-svn: 330702
2018-04-24 09:55:39 +00:00
Rafael Espindola aded409325 Simplify getOffset for synthetic sections.
We had a single symbol using -1 with a synthetic section. It is
simpler to just update its value.

This is not a big will by itself, but will allow having a simple
getOffset for InputSeciton.

llvm-svn: 330340
2018-04-19 16:54:30 +00:00
Michael J. Spencer b842725c1d [ELF] Add profile guided section layout
This adds profile guided layout using the Call-Chain Clustering (C³) heuristic
from https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf .

RFC: [llvm-dev] [RFC] Profile guided section layout
     http://lists.llvm.org/pipermail/llvm-dev/2017-June/114178.html

Pass `--call-graph-ordering-file <file>` to read a call graph profile where each
line has the format:

    <from symbol> <to symbol> <call count>

Differential Revision: https://reviews.llvm.org/D36351

llvm-svn: 330234
2018-04-17 23:30:05 +00:00
George Rimar c552619fc1 [ELF] - Reorder local symbols.
This fixes PR36716 (https://bugs.llvm.org/show_bug.cgi?id=36716),

Patch sorts local symbols to match the
following order: file1, local1, hidden1, file2, local2, hidden2 ...

Differential revision: https://reviews.llvm.org/D45325

llvm-svn: 329787
2018-04-11 09:24:27 +00:00
George Rimar 9f0b8e8025 [ELF] - Simplify. NFC.
llvm-svn: 329785
2018-04-11 09:03:02 +00:00
Rafael Espindola 262589db70 Don't warn on ICFed symbols, warn on synthetic ones.
Based on a patch for the ICF warning by Rui.

llvm-svn: 329757
2018-04-10 21:13:52 +00:00
George Rimar e160473823 [ELF] - Do not crash when trying to order --defsym/linker script symbols.
Currently, we crash because File is null for
such symbols.

Differential revision: https://reviews.llvm.org/D45440

llvm-svn: 329678
2018-04-10 09:44:44 +00:00
George Rimar 0029f21482 [ELF] - Stop setting OutSecOff too early.
Currently LLD sets OutSecOff in addSection for input sections.
That is a fake offset (just a rude approximation to remember the order), 
used for sorting SHF_LINK_ORDER sections
(see resolveShfLinkOrder, compareByFilePosition).

There are 2 problems with such approach:

1. We currently change and reuse Size field as a value assigned. Changing size is
not good because leads to bugs. Currently, SIZEOF(.bss) for empty .bss returns 2
because we add two empty synthetic sections and increase size twice by 1. 
(See PR37011: https://bugs.llvm.org/show_bug.cgi?id=37011)

2. Such approach simply does not work when --symbol-ordering-file is involved,
because processing of the ordering file might break the initial section order.

This fixes PR37011.

Differential revision: https://reviews.llvm.org/D45368

llvm-svn: 329560
2018-04-09 13:01:50 +00:00
George Rimar 7bf92be676 [ELF] - Allow LLD to produce file symbols.
This is for PR36716 and
this enables emitting STT_FILE symbols.

Output size affect is minor:
lld binary size changes from 52,883,408 to 52,949,400
clang binary size changes from 83,136,456 to 83,219,600

Differential revision: https://reviews.llvm.org/D45261

llvm-svn: 329557
2018-04-09 11:43:52 +00:00
Rafael Espindola 3bd98b1031 Change which file we print when a symbol cannot be ordered.
Currently there are a few odd things about the warning about symbols
that cannot be ordered. This patch fixes:

* When there is an undefined symbol that resolves to a shared file, we
  were printing the location of the undefined reference.

* If there are multiple comdats, we were reporting them all.

llvm-svn: 329371
2018-04-06 03:36:19 +00:00
Eugene Leviant 57225ac179 [ELF] Don't add NOLOAD sections to segment
Differential revision: https://reviews.llvm.org/D45264

llvm-svn: 329281
2018-04-05 13:23:59 +00:00
George Rimar 94e148c830 [ELF] - Rename checkSectionOverlap() to checkSections(). NFC.
Renaming was requested in post commit review for D43820.

llvm-svn: 329159
2018-04-04 09:24:31 +00:00
Rui Ueyama c6bf37d56d Instead of using std::copy, clear the vector first and add new elements. NFC.
Differential Revision: https://reviews.llvm.org/D45227

llvm-svn: 329107
2018-04-03 20:08:45 +00:00
Peter Collingbourne bca630bd61 ELF: Use a vector of pairs to sort sections ordered using --symbol-ordering-file.
This improved performance by 0.5-1% linking Chromium for Android.

Differential Revision: https://reviews.llvm.org/D45222

llvm-svn: 329106
2018-04-03 19:45:10 +00:00
George Rimar 1fc9f39bd5 [ELF] - Check that output sections fit in address space.
Added checks to test that we do not produce
output where VA of sections overruns the address
space available.

Differential revision: https://reviews.llvm.org/D43820

llvm-svn: 329063
2018-04-03 12:39:28 +00:00
George Rimar 8fcd04b786 [ELF] - Fix the comment. NFC.
llvm-svn: 329062
2018-04-03 12:28:53 +00:00
Peter Collingbourne 5ea6d50af1 ELF: Place ordered sections in the middle of the unordered section list on targets with limited-range branches.
It generally does not matter much where we place sections ordered
by --symbol-ordering-file relative to other sections. But if the
ordered sections are hot (which is the case already for some users
of --symbol-ordering-file, and is increasingly more likely to be
the case once profile-guided section layout lands) and the target
has limited-range branches, it is beneficial to place the ordered
sections in the middle of the output section in order to decrease
the likelihood that a range extension thunk will be required to call
a hot function from a cold function or vice versa.

That is what this patch does. After D44966 it reduces the size of
Chromium for Android's .text section by 60KB.

Differential Revision: https://reviews.llvm.org/D44969

llvm-svn: 328905
2018-03-30 21:36:54 +00:00
Rumeet Dhindsa 7588a8e89d Initialize Elf Header to zero to ensure that bytes not assigned any value later on are initialized properly.
Differential Revision: https://reviews.llvm.org/D44986

llvm-svn: 328902
2018-03-30 20:49:34 +00:00
Rui Ueyama 5706161806 Simplify. NFC.
llvm-svn: 328817
2018-03-29 19:51:53 +00:00
Rui Ueyama fb1db6ae43 Exit early from a loop. NFC.
This patch fixes an issue introduced in r328810 which made the algorithm
to always run the loop O(n^2) times, though we can break early. The
output remains the same.

llvm-svn: 328811
2018-03-29 18:29:12 +00:00
Rui Ueyama 09fcdbc131 Refactor Writer::checkNoOverlappingSections. NFC.
This patch rewrites the function to remove lambda callbacks and use
of template. The algorithm is the same as before.

llvm-svn: 328810
2018-03-29 18:24:01 +00:00
Rui Ueyama 2ce7401505 Unloop a for-loop so that we can comment on each symbol. NFC.
llvm-svn: 328736
2018-03-28 22:09:40 +00:00
Rui Ueyama e86c7956d6 Merge nested "if"s. NFC.
llvm-svn: 328733
2018-03-28 21:53:10 +00:00
Rafael Espindola f065390f6c Reduce code duplication a bit. NFC
llvm-svn: 328569
2018-03-26 18:49:31 +00:00
George Rimar 16f11462ce [ELF] - Simplify. NFC.
llvm-svn: 328319
2018-03-23 14:43:51 +00:00
George Rimar 42c939c6c1 [ELF] - Apply clang-format. NFC.
llvm-svn: 328195
2018-03-22 13:47:56 +00:00
George Rimar 8ee7947fb4 [ELF] - Make __start_/__stop_<section_name> symbols STV_PROTECTED
There are no reasons for them to be STV_DEFAULT,
recently bfd did the same change.

Differential revision: https://reviews.llvm.org/D44566

llvm-svn: 327983
2018-03-20 14:22:10 +00:00
Zaara Syeda 52ed6eb8d9 [ELF] Add basic support for PPC LE
This patch adds changes to start supporting the Power 64-Bit ELF V2 ABI.
This includes:
- Changing the ElfSym::GlobalOffsetTable to be named .TOC.
- Creating a GotHeader so the first entry in the .got is .TOC.
- Setting the e_flags to be 1 for ELF V1 and 2 for ELF V2

Differential Revision: https://reviews.llvm.org/D44483

llvm-svn: 327871
2018-03-19 17:40:14 +00:00
Peter Smith 3d044f57d4 [ELF] Recommit 327248 with Arm using the .got for _GLOBAL_OFFSET_TABLE_
This is the same as 327248 except Arm defining _GLOBAL_OFFSET_TABLE_ to
be the base of the .got section as some existing code is relying upon it.

For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at
the start of the .got.plt section so that _GLOBAL_OFFSET_TABLE_[0] =
reserved value that is by convention the address of the dynamic section.
Previously we had defined _GLOBAL_OFFSET_TABLE_ as either the start or end
of the .got section with the intention that the .got.plt section would
follow the .got. However this does not always hold with the current
default section ordering so _GLOBAL_OFFSET_TABLE_[0] may not be consistent
with the reserved first entry of the .got.plt.

X86, X86_64 and AArch64 will use the .got.plt. Arm, Mips and Power use .got

Fixes PR36555

Differential Revision: https://reviews.llvm.org/D44259

llvm-svn: 327823
2018-03-19 06:52:51 +00:00
Peter Collingbourne 5c902845e5 Revert r327248, "For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at"
This change broke ARM code that expects to be able to add
_GLOBAL_OFFSET_TABLE_ to the result of an R_ARM_REL32.

I will provide a reproducer on llvm-commits.

llvm-svn: 327688
2018-03-16 01:01:44 +00:00
Rui Ueyama db46a62e2b Implement --cref.
This is an option to print out a table of symbols and filenames.
The output format of this option is the same as GNU, so that it can be
processed by the same scripts as before after migrating from GNU to lld.

This option is mildly useful; we can live without it. But it is pretty
convenient sometimes, and it can be implemented in 50 lines of code, so
I think lld should support this option.

Differential Revision: https://reviews.llvm.org/D44336

llvm-svn: 327565
2018-03-14 20:29:45 +00:00
George Rimar 2313086726 [ELF] - Restrict section offsets that exceeds file size.
This is part of PR36515.

With some linkerscripts it is possible to get file offset overlaps
and overflows. Currently LLD checks overlaps in checkNoOverlappingSections().
And also we allow broken output with --no-inhibit-exec.
Problem is that sometimes final offset of sections is completely broken
and we calculate output file size wrong and might crash.

Patch implements check to verify that there is no output section
which offset exceeds file size.

Differential revision: https://reviews.llvm.org/D43819

llvm-svn: 327376
2018-03-13 08:47:17 +00:00
Peter Smith 18aa0be36e For most Targets the _GLOBAL_OFFSET_TABLE_ symbol is expected to be at
the start of the .got.plt section so that _GLOBAL_OFFSET_TABLE_[0] =
reserved value that is by convention the address of the dynamic section.
Previously we had defined _GLOBAL_OFFSET_TABLE_ as either the start or end
of the .got section with the intention that the .got.plt section would
follow the .got. However this does not always hold with the current
default section ordering so _GLOBAL_OFFSET_TABLE_[0] may not be consistent
with the reserved first entry of the .got.plt.

X86, X86_64, Arm and AArch64 will use the .got.plt. Mips and Power use .got

Fixes PR36555

Differential Revision: https://reviews.llvm.org/D44259

llvm-svn: 327248
2018-03-11 20:58:18 +00:00
Rui Ueyama 301305fd3d Use exact uint32_t for uint32_t ELF field. NFC.
llvm-svn: 326934
2018-03-07 19:25:36 +00:00
George Rimar bf3c384673 [ELF] - Adjust rangeToString to report ranges in a different format.
It was raised during the review of D43819.

LLD usually use [X, Y] for reporting ranges, like below:
"relocation R_386_16 out of range: 65536 is not in [0, 65535]"

Patch changes rangeToString() to do the same.

Differential revision: https://reviews.llvm.org/D44207

llvm-svn: 326918
2018-03-07 17:54:25 +00:00
Rui Ueyama b0084a0eee Revert r326911: Improve --warn-symbol-ordering.
This reverts commit r326911 because it was committed by accident.

llvm-svn: 326914
2018-03-07 17:24:46 +00:00
Rui Ueyama ebfab927d9 Improve --warn-symbol-ordering.
Summary:
I originally tried to simplify code and then noticed that lld doesn't
do what it tells to the user by warn(). It says "unable to order
discarded symbol" but it actually can for sections eliminated by ICF.
With this patch, lld doesn't sort such sections.

Reviewers: jhenderson, rafael

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D44180

llvm-svn: 326911
2018-03-07 17:15:06 +00:00
Rui Ueyama 37ad8161e4 Do not create multiple NOTE segments.
Previously, we didn't try to make effort to put .note sections next
to each other in the output file, so two .note sections were likely
to be stored to two separate NOTE segments. That's undesirable because
we should create as few segments as possible in general.

Differential Revision: https://reviews.llvm.org/D43858

llvm-svn: 326410
2018-03-01 02:31:29 +00:00
Rafael Espindola 852bd5c062 Simplify removing empty output sections.
With this the meaning of the Live bit in output sections is clear: we
have at some point added a input section into it.

llvm-svn: 326401
2018-03-01 01:08:00 +00:00
Rui Ueyama ee17371897 Merge {COFF,ELF}/Strings.cpp to Common/Strings.cpp.
This should resolve the issue that lld build fails in some hosts
that uses case-insensitive file system.

Differential Revision: https://reviews.llvm.org/D43788

llvm-svn: 326339
2018-02-28 17:38:19 +00:00
George Rimar 46045364b2 [ELF] - Format, fix mistype. NFC.
llvm-svn: 326198
2018-02-27 14:06:47 +00:00
George Rimar a77b963c90 [ELF] - Fix case of using both --icf and --symbol-ordering-file together.
Imagine that we have sections A, B, C, where A == C and
symbol ordering file containing symbols: symC, symB, symA

Previously because of ICF it was possible that final order would be
B, A or B, C. That violates order specified in ordering file.
Patch changes that.

Differential revision: https://reviews.llvm.org/D43234

llvm-svn: 326179
2018-02-27 08:26:38 +00:00
Rafael Espindola 79c23eec04 Keep flags from phantom synthetic sections.
This fixes pr36475.

I think this code can be simplified a bit, but I would like to check
in the more direct fix if we are in agreement on the direction and
then refactor.

This is not something that bfd does. The issue is not noticed in bfd
because it keeps fewer sections from the linkerscript in the output.

The reasons why it seems reasonable to do this:

- As George noticed, we would still keep the flags if the output
  section had both an empty synthetic section and a regular section
- We need an heuristic to find the flags of output sections. Using the
  flags of a synthetic section that would have been there seems a
  reasonable heuristic.

llvm-svn: 326137
2018-02-26 22:32:15 +00:00
George Rimar 0c97f4eba4 [ELF] - Fix variable name and mistype in comment. NFC.
llvm-svn: 326090
2018-02-26 15:16:03 +00:00
Simon Atanasyan a4cde9d2e2 [ELF][MIPS] Set EI_ABIVERSION flag accordingly to MIPS ABIs requirement
MIPS ABIs require that if an executable file uses non-PIC model, the
EI_ABIVERSION entry in the ELF header should be incremented from 0 to 1.
That allows obsoleted / limited dynamic linkers refuse to link them.

llvm-svn: 325890
2018-02-23 11:28:57 +00:00
George Rimar db1a062447 [ELF] - Do not remove empty output sections that are explicitly assigned to phdr in script.
This continues direction started in D43069.

We can keep sections that are explicitly assigned to segment in script.
It helps to simplify code.

Differential revision: https://reviews.llvm.org/D43571

llvm-svn: 325887
2018-02-23 10:53:04 +00:00
Fangrui Song 9cd5df0e15 [ELF] Add comment for preemptible and fix typo. NFC
Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D43642

llvm-svn: 325855
2018-02-23 02:05:48 +00:00
George Rimar 925529b821 [ELF] - Rewrote outdated comment. NFC.
llvm-svn: 325809
2018-02-22 17:52:43 +00:00
George Rimar 563e4f2f58 [ELF] - Introduce getInputSections() helper.
We sometimes need to iterate over input sections for a given
output section. It is not very convinent because we have to iterate
over section descriptions.
Patch introduces getInputSections helper, it simplifies things.

Differential revision: https://reviews.llvm.org/D43574

llvm-svn: 325763
2018-02-22 09:55:28 +00:00
George Rimar 5bd90e2db1 [ELF] - Simplify. NFC.
llvm-svn: 325681
2018-02-21 14:21:23 +00:00
Igor Kudrin 25f917341e [ELF] Simplify handling of AT section attribute.
This also makes the behavior close to GNU ld's.

Differential Revision: https://reviews.llvm.org/D43284

llvm-svn: 325213
2018-02-15 06:13:52 +00:00
James Henderson de300e66bb [ELF] Add warnings for various symbols that cannot be ordered
There are a number of different situations when symbols are requested
to be ordered in the --symbol-ordering-file that cannot be ordered for
some reason. To assist with identifying these symbols, and either
tidying up the order file, or the inputs, a number of warnings have
been added. As some users may find these warnings unhelpful, due to how
they use the symbol ordering file, a switch has also been added to
disable these warnings.

The cases where we now warn are:

 * Entries in the order file that don't correspond to any symbol in the input
 * Undefined symbols
 * Absolute symbols
 * Symbols imported from shared objects
 * Symbols that are discarded, due to e.g. --gc-sections or /DISCARD/ linker script sections
 * Multiple of the same entry in the order file

Reviewed by: rafael, ruiu

Differential Revision: https://reviews.llvm.org/D42475

llvm-svn: 325125
2018-02-14 13:36:22 +00:00
Rafael Espindola 1d76120d9a Use a stricter return type in buildSectionOrder. NFC.
We sort inside output sections, so all the sections we see should be
InputSectionBase.

I noticed the patch adding callgraph based section ordering used this
type and changing this separately makes the merge easier.

llvm-svn: 325094
2018-02-14 01:42:26 +00:00
Rui Ueyama 3cd48fb124 Remove 'z' in .zdebug when decompressing a section.
When decompressing a compressed debug section, we drop SHF_COMPRESSED
flag but we didn't drop "z" in ".zdebug" section name. This patch does
that for consistency.

This change also fixes the issue that .zdebug_gnu_pubnames are not
dropped when we are creating a .gdb_index section.

llvm-svn: 324949
2018-02-12 22:25:45 +00:00
Rafael Espindola ecfd73457c Refactor how we decide which sections to sort.
This is a bit more verbose, but it has a few advantages.

The logic on what to do with special sections like .init_array is not
duplicated. Before we would need keep isKnownNonreorderableSection in
sync.

I think with this the call graph based sorting can be implemented by
"just" returning a new order from buildSectionOrder.

llvm-svn: 324744
2018-02-09 16:09:22 +00:00
Michael J. Spencer e43db0e89e [ELF] Don't sort non reorderable sections with --symbol-ordering-file
Differential Revision: https://reviews.llvm.org/D43038

llvm-svn: 324656
2018-02-08 22:03:23 +00:00
George Rimar 3d5e86e5ee [ELF] - Remove unused synthetic sections correctly.
This is PR35740 which now crashes
because we remove unused synthetic sections incorrectly.

We can keep input section description and corresponding output
section live even if it must be empty and dead. 
This results in a crash because SHF_LINK_ORDER handling code
tries to access first section which is nullptr in this case.

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D42681

llvm-svn: 324463
2018-02-07 09:11:07 +00:00
Rafael Espindola 339dbb8af2 Convert a use of Config->Static.
In lld this was the only use of Config->Static where it meant anything
else other than "use .a instead of .so".

If a program turns out to not use any dynamic libraries, we should
produce the same result with and without -static.

llvm-svn: 324421
2018-02-06 22:59:24 +00:00
Rui Ueyama 6a8e79b8e5 Add -{no,}-check-sections flags to enable/disable section overlchecking
GNU linkers have this option.

Differential Revision: https://reviews.llvm.org/D42858

llvm-svn: 324150
2018-02-02 22:24:06 +00:00
Alexander Richardson 6b367faa45 [ELF] Make overlapping output sections an error
Summary:
While trying to make a linker script behave the same way with lld as it did
with bfd, I discovered that lld currently doesn't diagnose overlapping
output sections. I was getting very strange runtime failures which I
tracked down to overlapping sections in the resulting binary. When linking
with ld.bfd overlapping output sections are an error unless
--noinhibit-exec is passed and I believe lld should behave the same way
here to avoid surprising crashes at runtime.

The patch also uncovered an errors in the tests: arm-thumb-interwork-thunk
was creating a binary where .got.plt was placed at an address overlapping
with .got.

Reviewers: ruiu, grimar, rafael

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D41046

llvm-svn: 323856
2018-01-31 09:22:44 +00:00
Rafael Espindola c7945c827d Move function to the file where it is used.
llvm-svn: 323780
2018-01-30 16:24:04 +00:00
Rafael Espindola 22d533568b Sort orphan section if --symbol-ordering-file is given.
Before this patch orphan sections were not sorted.

llvm-svn: 323779
2018-01-30 16:20:08 +00:00
Rafael Espindola a0d7df3988 Put the header in the first PT_LOAD even if that PT_LOAD has a LMAExpr.
This should fix PR36017.

The root problem is that we were creating a PT_LOAD just for the
header. That was technically valid, but inconvenient: we should not be
making the ELF discontinuous.

The solution is to allow a section with LMAExpr to be added to a
PT_LOAD if that PT_LOAD doesn't already have a LMAExpr.

llvm-svn: 323625
2018-01-29 03:44:44 +00:00
Rafael Espindola db9dd5b43e Improve LMARegion handling.
This fixes the crash reported at PR36083.

The issue is that we were trying to put all the sections in the same
PT_LOAD and crashing trying to write past the end of the file.

This also adds accounting for used space in LMARegion, without it all
3 PT_LOADs would have the same physical address.

llvm-svn: 323449
2018-01-25 17:42:03 +00:00
Rafael Espindola a9263c8963 Fix lld crash introduced by r321154.
Since SyntheticSection::getParent() may return null, dereferencing
this pointer in ARMExidxSentinelSection::empty() call from
removeUnusedSyntheticSections() results in crashes when linking ARM
binaries.

Patch by vit9696!

llvm-svn: 323366
2018-01-24 19:16:31 +00:00
Rui Ueyama e2dfdbf0aa Do not pass an argument that can be easily inferred from other argument.
llvm-svn: 322416
2018-01-12 22:29:29 +00:00
George Rimar 9fc2c64b35 [ELF] - Do not use HeaderSize for conditions in PltSection.
Previously we checked (HeaderSize == 0) to find out if
PltSection section is IPLT or PLT. Some targets does not set
HeaderSize though. For example PPC64 has no lazy binding implemented
and does not set PltHeaderSize constant.

Because of that using of both IPLT and PLT relocations worked
incorrectly there (testcase is provided).

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D41613

llvm-svn: 322362
2018-01-12 09:35:57 +00:00
Rui Ueyama 0657e5c3f2 Do not use parallelForEach to call maybeCompress().
Currently LLVM's paralellForEach has a problem with reentracy.
That caused https://bugs.llvm.org/show_bug.cgi?id=35788 (lld somtimes
hangs while linking Ruby 2.4) because maybeCompress calls writeTo which
uses paralellForEach.

This patch is to avoid using paralellForEach to call maybeCompress
to workaround the issue.

llvm-svn: 322041
2018-01-08 23:12:42 +00:00
James Henderson e1689689d8 [ELF] Compress debug sections after assignAddresses and support custom layout
Previously, in r320472, I moved the calculation of section offsets and sizes
for compressed debug sections into maybeCompress, which happens before
assignAddresses, so that the compression had the required information. However,
I failed to take account of relocations that patch such sections. This had two
effects:

1. A race condition existed when a debug section referred to a different debug
section (see PR35788).
2. References to symbols in non-debug sections would be patched incorrectly.
This is because the addresses of such symbols are not calculated until after
assignAddresses (this was a partial regression caused by r320472, but they
could still have been broken before, in the event that a custom layout was used
in a linker script).

assignAddresses does not need to know about the output section size of
non-allocatable sections, because they do not affect the value of Dot. This
means that there is no longer a reason not to support custom layout of
compressed debug sections, as far as I'm aware. These two points allow for
delaying when maybeCompress can be called, removing the need for the loop I
previously added to calculate the section size, and therefore the race
condition. Furthermore, by delaying, we fix the issues of relocations getting
incorrect symbol values, because they have now all been finalized.

llvm-svn: 321986
2018-01-08 10:17:03 +00:00
Rafael Espindola 2640a0a5e5 Align SHT_NOBITS sections is they are the first on a PT_LOAD.
We normally want to ignore SHT_NOBITS sections when computing
offsets. The sh_offset of section itself seems to be irrelevant and

- If the section is in the middle of a PT_LOAD, it will make no
  difference on the computed offset of the followup section.

- If it is in the end of a PT_LOAD, we want to avoid its alignment
  changing the offset of the followup sections.

The issue is if it is at the start of the PT_LOAD. In that case we do
have to align it so that the following sections have congruent address
and offset module the page size. We were not handling this case.

This should fix freebsd kernel link.

llvm-svn: 321657
2018-01-02 16:46:30 +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
Igor Kudrin 5966d15943 [ELF] Fix an assignment command at the end of an .ARM.exidx section.
The value of the symbol in the assignment should include the sentinel entry.

Differential Revision: https://reviews.llvm.org/D41234

llvm-svn: 321154
2017-12-20 08:56:10 +00:00
Peter Smith 96ca4f5e91 [ELF] Remove Duplicate .ARM.exidx sections
The ARM.exidx section contains a table of 8-byte entries with the first
word of each entry an offset to the function it describes and the second
word instructions for unwinding if an exception is thrown from that
function. The SHF_LINK_ORDER processing will order the table in ascending
order of the functions described by the exception table entries. As the
address range of an exception table entry is terminated by the next table
entry, it is possible to merge consecutive table entries that have
identical unwind instructions.

For this implementation we define a table entry to be identical if:
- Both entries are the special EXIDX_CANTUNWIND.
- Both entries have the same inline unwind instructions.
We do not attempt to establish if table entries that are references to
.ARM.extab sections are identical.

This implementation works at a granularity of a single .ARM.exidx
InputSection. If all entries in the InputSection are identical to the
previous table entry we can remove the InputSection. A more sophisticated
but more complex implementation would rewrite InputSection contents so that
duplicates within a .ARM.exidx InputSection can be merged.

Differential Revision: https://reviews.llvm.org/D40967

llvm-svn: 320803
2017-12-15 11:09:41 +00:00
Peter Smith cf354873c1 [ELF] Complete implementation of --fix-cortex-a53-843419
This patch provides the mechanism to fix instances of the instruction
sequence that may trigger the cortex-a53 843419 erratum. The fix is
provided by an alternative instruction sequence to remove one of the
erratum conditions. To reach this alternative instruction sequence we
replace the original instruction with a branch to the alternative
sequence. The alternative sequence is responsible for branching back to
the original.

As there is only erratum to fix the implementation is specific to
AArch64 and the specific erratum conditions. It should be generalizable
to other targets and erratum if needed.

Differential Revision: https://reviews.llvm.org/D36749

llvm-svn: 320800
2017-12-15 10:32:34 +00:00
Rafael Espindola f4fb5fd752 Move Repl to SectionBase.
It is currently in InputSectionBase. Only InputSections are used in
ICF, so Repl should be move to InputSection to clear the class
hierarchy or, like this patch does, to SectionBase for convenience.

The convenience of having it on the base class is that we can just
access the replacement without having to first check if it is an
InputSection. It is a bit less code and a bit faster as some of this
code is very hot.

I got up to 1.77% improvement in clang-gdb-index and no regressions
according to lnt.

llvm-svn: 320654
2017-12-13 22:59:23 +00:00
Peter Smith 03cbf468cd [ELF] Move SHF_LINK_ORDER processing earlier in Writer.cpp [NFC]
By moving this step before thunk creation and other processing that depends
on the size of sections, we permit removal of duplicates in the .ARM.exidx
section.

Differential Revision: https://reviews.llvm.org/D40964

llvm-svn: 320477
2017-12-12 13:30:44 +00:00
Petr Hosek d663de3e18 [ELF] Don't set the executable bit for relocatable files
These are not executable files so they shouldn't be marked as such.

Differential Revision: https://reviews.llvm.org/D41041

llvm-svn: 320438
2017-12-11 23:30:54 +00:00
Rafael Espindola 63fcc5cccc Create reserved symbols early so they can be versioned.
This fixes pr35570.

We were creating these symbols after parsing version scripts, so they
could not be versioned.

We cannot move the version script parsing later because we need it for
lto.

One option is to move both addReservedSymbols and
createSyntheticSections earlier. The disadvantage is that some
sections created by createSyntheticSections replace other input
sections. For example, gdb index replaces .debug_gnu_pubnames, so it
wants to run after gc sections so that it can set S->Live to false.

What this patch does instead is to move just the ElfHeader creation
early.

llvm-svn: 320390
2017-12-11 17:23:28 +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 5af073e3bf Make createSyntheticSections a static helper. NFC.
llvm-svn: 320200
2017-12-08 21:50:29 +00:00
Rafael Espindola 471001a7b4 Make findSection a static function. NFC.
llvm-svn: 320198
2017-12-08 21:44:11 +00:00
Rafael Espindola 1dd30ddd45 Make addReservedSymbols a static helper. NFC.
llvm-svn: 320175
2017-12-08 19:13:27 +00:00
Peter Smith 732cd8cbef [ELF] Implement scanner for Cortex-A53 Erratum 843419
Add a new file AArch64ErrataFix.cpp that implements the logic to scan for
the Cortex-A53 Erratum 843419. This involves finding all the executable
code, disassembling the instructions that might trigger the erratum and
reporting a message if the sequence is detected.

At this stage we do not attempt to fix the erratum, this functionality
will be added in a later patch. See D36749 for proposal.

Differential Revision: https://reviews.llvm.org/D36742

llvm-svn: 319780
2017-12-05 15:59:05 +00:00
Peter Smith 7c40f93f38 [ELF] InX::BssRelRo should check section contents before marking relro
When a linker script is used with a pattern like { *(.bss .bss.*) } the
InX::BssRelRo section will match against .bss.*. By matching on the name
only, in the same way that .data.rel.ro works we prevent this
from happening, but permit scripts that want to explicitly provide
a .bss.rel.ro OutputSection.
    
Differential Revision: https://reviews.llvm.org/D40735

llvm-svn: 319755
2017-12-05 11:15:58 +00:00
Rafael Espindola b70824c1b8 Revert r318924 Skip over empty sections when checking for contiguous relro
PR35478 https://bugs.llvm.org/show_bug.cgi?id=35478 points out a flaw
in the implementation of r318924 from D40364. The implementation
depends on the Size field being set or the SyntheticSection::empty()
being accurate. These functions are not reliable as some linker script
commands that have yet to be processed may affect the results, causing
some non-zero size sections to be reported as zero size.

I think the first step is to revert r318924 and come up with a better
solution for the underlying problem rather than trying to layer more
heuristics onto the zero sized output section.

Chances are I'll be out of office by the time anyone sees this so feel
free to commit the revert if you agree with me.

Fixes PR35478

Current thoughts on the underlying problem:

Revisiting the motivation for adding the zero size check in the first
place; it was to prevent 0 sized SyntheticSections that a user does
not have full control over from needlessly breaking the PT_GNU_RELRO,
rather than trying to accommodate arbitrarily complex linker
scripts. Looking at the code, it looks like
removeUnusedSyntheticSections() should remove zero sized synthetic
sections. It does, but it doesn't set the Parent to nullptr, this has
the side effect that Sec == InX::BssRelRo->getParent() will make the
parent OutputSection of InX::BssRelRo RelRo even if there is no
InX::BssRelRo.

I tried a quick experiment with setting the Parent to nullptr and this
flushed out a few interesting test failures, it feels like playing
Jenga with every change:

    In the isRelroSection() we have to consider the case where there
    is no .plt and .plt.got but there is a ifunc plt with accompanying
    (ifunc .got or .plt.got)

    The PPC64 has PltHeaderSize == 0. Unfortunately HeaderSize == 0 is
    used to choose between the ifunc plt or normal plt. We seem to get
    away with this at the moment, but tests start to fail when Parent
    is set to nullptr for the .got.plt.

    The InX::BssRelRo and InX::Bss never get their sizes set and they
    are always removed by removeUnusedSyntheticSections(), their
    purpose seems to be as some kind of proxy for add .bss or
    .bss.relro InputSections into their parent OutputSections, they
    therefore don't behave like other SyntheticSections anyway.

My thinking is that some work is needed to make sure that the Sec ==
SyntheticSection->getParent() does a bit more checking before
returning true, particularly for InX::BssRelRo as that has special
behaviour. I'll hope to post something for review as soon as possible.

Patch by Peter Smith!

llvm-svn: 319563
2017-12-01 18:14:14 +00:00
George Rimar 196be4a18e [ELF] - Rename excessive variable. NFC.
It is a follow up for 
https://reviews.llvm.org/D40652 requested during review.

llvm-svn: 319527
2017-12-01 09:14:56 +00:00
George Rimar 78e27e830d [ELF] - Produce relocation section name consistent with output section name when --emit-reloc used with linker script.
This is for "Bug 35474 - --emit-relocs produces wrongly-named reloc sections".

LLD currently for scripts like:

.text.boot : { *(.text.boot) }
emits relocation section with name .rela.text because does not take
redefined name of output section into account and builds section name
using rules for non-scripted case. Patch fixes this oddness.

Differential revision: https://reviews.llvm.org/D40652

llvm-svn: 319526
2017-12-01 09:04:52 +00:00
Rui Ueyama 8ed548a481 Fix typo.
llvm-svn: 319394
2017-11-30 01:04:26 +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
Igor Kudrin a46522f369 Revert r319008, "[ELF] Do not keep symbols if they referenced only from discarded sections."
and r319051, "Add a missing test."

r319008 broke the LTO bots;
r319051 depends on changes in r319008.

llvm-svn: 319154
2017-11-28 08:39:40 +00:00
Igor Kudrin 40007586fc [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.

Differential Revision: https://reviews.llvm.org/D38790

llvm-svn: 319008
2017-11-27 05:51:10 +00:00
Peter Smith 80e4be7eae [ELF] Rename .bss.rel.ro to .data.rel.ro.bss for some Linker Scripts.
LLD uses .bss.rel.ro for read-only copy relocations whereas the ld.bfd and
gold linkers use .data.rel.ro. In some linker scripts including ld.bfd's
internal linker script, the relro sections are placed sequentially assuming
.data.rel.ro is used. LLD's use of .bss.rel.ro means that the copy
relocations get matched into the .bss section causing the relro sections to
be non-contiguous.

This change checks for a .data.rel.ro OutputSection when a linker script
with the SECTIONS command is used. The section will match in the
.data.rel.ro output section and will maintain contiguous relro.

Differential Revision: https://reviews.llvm.org/D40365

Fixes PR35265

llvm-svn: 318940
2017-11-24 08:48:29 +00:00
Peter Smith c076b280df [ELF] Skip over empty sections when checking for contiguous relro
When checking for contiguous relro sections we can skip over empty sections.
If there is an empty non-relro section in the middle of a contiguous block
of relro sections then it cannot be written to so it is safe to include in
PT_GNU_RELRO header. If there is a contiguous block of empty relro sections
then no PT_GNU_RELRO header is required for them.

Differential Revision: https://reviews.llvm.org/D40364

llvm-svn: 318924
2017-11-23 15:10:00 +00:00
Peter Smith dc3bd88b22 [ELF] Give error message when relro sections are not contiguous.
If a linker script is used that names linker generated synthetic sections
it is possible that the OutputSections for which isRelroSection() is true
are not contiguous. When the relro sections are not contiguous we cannot
describe them with a single PT_GNU_RELRO PHDR. Unfortunately at least one
contemporary dynamic loader only supports one PT_GNU_RELRO PHDR so we
cannot output more than one of these PHDRs. As not including relro
sections in the PHDR will lead to security sensitive sections being
writeable we choose to give an error message instead.

Differential Revision: https://reviews.llvm.org/D40359

[ELF] Skip over empty sections when checking for contiguous relro

llvm-svn: 318920
2017-11-23 14:53:10 +00:00
Rafael Espindola de56343cf0 Simplify as-needed handling.
This is a reduction of a patch by Rui Ueyama.

llvm-svn: 318852
2017-11-22 17:50:42 +00:00
George Rimar 80355234f7 [ELF] - Allow applying SHF_MERGE optimization for relocatable output.
This fixes PR35223.

Here I enabled SHF_MERGE section content merging for -r like
we do for regular linking.

Differential revision: https://reviews.llvm.org/D40026

llvm-svn: 318516
2017-11-17 11:27:57 +00:00
Rafael Espindola bec3765bea Remove IsLocal.
Since we always have Binding in the current symbol design IsLocal is
redundant.

llvm-svn: 318497
2017-11-17 01:37:50 +00:00
George Rimar 661a2c1970 [ELF] - Don't emit broken relocations for SHF_MERGE sections when --emit-relocs is used.
Previously our relocations we rewrote were broken for that case.
We emited incorrect addend and broken relocation info field
because did not produce section symbol for mergeable synthetic sections.

Differential revision: https://reviews.llvm.org/D40070

llvm-svn: 318394
2017-11-16 12:33:36 +00:00
Rafael Espindola a4884cc38f Try harder to delete the temporary file.
It is really hard to cover restarts in a debugger, SIGKILL or power
failures. I will try to handle them in a followup patch, but it will
not support all the systems lld has to run on.

RemoveFileOnSignal takes care of crashes.

So what is left is making sure all regular exits delete the file. This
patch does that by moving the buffer to error handling. That is a bit
of a hack, but seemed better than to generalize it to take a callback on
construction.

I will implement this on COFF on the next patch.

llvm-svn: 318060
2017-11-13 18:06:43 +00:00
Rafael Espindola 5f903f3848 Update for llvm change.
llvm-svn: 317657
2017-11-08 01:50:34 +00:00
Rafael Espindola f7a57294d7 Update for llvm change.
llvm-svn: 317650
2017-11-08 01:05:52 +00:00
Peter Collingbourne b472aa0268 ELF: Remove function Symbol::isInCurrentOutput().
This function is now equivalent to isDefined().

llvm-svn: 317449
2017-11-06 04:39:07 +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 aa8523e4b6 Move OutputSectionFactory to LinkerScript.cpp. NFC.
That class is used only by LinkerScript.cpp, so we should move it to
that file. Also, it no longer has to be a "factory" class. It can just
be a non-member function.

llvm-svn: 317427
2017-11-04 23:54:25 +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 8c0cdca99e [ELF] - Removed unused variable. NFC.
llvm-svn: 317316
2017-11-03 11:51:58 +00:00
James Henderson 50baa593f1 [ELF] Remove unnecessary function call. NFC.
StringTableSection does not implement postThunkContents, so calling it on these 
sections is pointless (it calls an empty virtual function), and we can remove it.

Reviewers: ruiu

Differential Revision: https://reviews.llvm.org/D39460

llvm-svn: 317014
2017-10-31 17:28:44 +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
George Rimar f9b04fd91f [ELF] - Simplify output section creation.
When there is no SECTION commands given, all sections are
technically orphans, but now we handle script orphans sections
and regular "orphans" sections for non-scripted case differently,
though we can handle them at one place.

Patch do that change.

Differential revision: https://reviews.llvm.org/D39045

llvm-svn: 316984
2017-10-31 10:31:58 +00:00
George Rimar a6b1fbece1 [ELF] - Stop sorting input sections in createSections().
It does not seem that createSections() is a good place for
applying sorting. Patch changes code to do that inside
sortSections(), which looks more appropriate place.

Differential revision: https://reviews.llvm.org/D39371

llvm-svn: 316893
2017-10-30 10:12:49 +00:00
Peter Collingbourne e662436114 ELF: Correctly set edata if there are no .bss sections.
edata needs to be set to the end of the last mapped initialized
section. We were previously mishandling the case where there were no
non-mapped sections by setting it to the end of the last section in
the output file.

Differential Revision: https://reviews.llvm.org/D39399

llvm-svn: 316877
2017-10-29 22:31:48 +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
Rui Ueyama bda337a8d8 Rename isInCurrentDSO -> isInCurrentOutput.
DSO is short for dynamic shared object, so the function name was a
little confusing because it sounded like it didn't work when we were
a creating statically-linked executable or something.

What we mean by "DSO" here is the current output file that we are
creating. Thus the new name. Alternatively, we could call it the current
ELF module, but "module" is a overloaded word, so I avoided that.

llvm-svn: 316809
2017-10-27 22:54:16 +00:00
Peter Collingbourne 5c54f15c55 ELF: Add support for emitting dynamic relocations in the Android relocation packing format.
The Android relocation packing format is a more compact
format for dynamic relocations in executables and DSOs
that is based on delta encoding and SLEBs. An overview
of the format can be found in the Android source code:
https://android.googlesource.com/platform/bionic/+/refs/heads/master/tools/relocation_packer/src/delta_encoder.h

This patch implements relocation packing using that format.

This implementation uses a more intelligent algorithm for compressing
relative relocations than Android's own relocation packer. As a
result it can generally create smaller relocation sections than
that packer. If I link Chromium for Android targeting ARM32 I get a
.rel.dyn of size 174693 bytes, as compared to 371832 bytes with gold
and the Android packer.

Differential Revision: https://reviews.llvm.org/D39152

llvm-svn: 316775
2017-10-27 17:49:40 +00:00
George Rimar 3396bf07a2 [ELF] - Stop naming relocation sections with first input section name.
It was reported (https://reviews.llvm.org/D38724#902841) that when we use 
-ffunction-sections --emit-relocs build, REL[A] output section receives the name of first
input section, like .rela.text.first_function_in_text rather than .rela.text.

It is probably not really an issue as sh_info still points to correct target section, but
it does not look clean in output and allows internal section name to leak there,
what at least looks confusing and is not consistent with ld.bfd.

Patch changes this behavior so that target output section name is used as a base.

Differential revision: https://reviews.llvm.org/D39242

llvm-svn: 316760
2017-10-27 11:38:31 +00:00
George Rimar 96b1157814 [ELF] - Simplify reporting of garbage collected sections.
This moves reporting of garbage collected sections right after
we do GC. That simplifies things.

Differential revision: https://reviews.llvm.org/D39058

llvm-svn: 316759
2017-10-27 11:32:22 +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
Rui Ueyama 0f46e45b03 Simplify logic to find the last executable segment. NFC.
llvm-svn: 316742
2017-10-27 05:08:39 +00:00
Rui Ueyama df15559c80 Fix typo.
llvm-svn: 316741
2017-10-27 04:59:33 +00:00
Rui Ueyama 02551abdca De-template EhFrameHdr. NFC.
llvm-svn: 316734
2017-10-27 03:14:24 +00:00
Rui Ueyama 572247f22e De-template EhFrameSection. NFC.
llvm-svn: 316731
2017-10-27 03:13:39 +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
Rui Ueyama 7b4eddf0ea Improve comment.
llvm-svn: 316489
2017-10-24 19:53:51 +00:00
Konstantin Zhuravlyov e7f1734f1a LLD/ELF: Allow targets to set e_flags
Differential Revision: https://reviews.llvm.org/D39139

llvm-svn: 316460
2017-10-24 17:01:40 +00:00
Petr Hosek 2fd533db9f [ELF] When placing orphans, handle case when last section is dead
r315292 introduced a change that's supposed to consistently ignore
"dead" output sections when placing orphans. Unfortunately, that
change doesn't handle the special case when the orphan section is
second to last section and the last section is dead (e.g. because
it's being discarded) introducing a regression in some cases.

This change handles this case by using the same predicate when
checking the last section.

Differential Revision: https://reviews.llvm.org/D39172

llvm-svn: 316307
2017-10-23 00:51:08 +00:00
Rafael Espindola 3558e24ae8 Remove unused argument.
llvm-svn: 316248
2017-10-20 23:28:19 +00:00
George Rimar 1c09dfe2bc [ELF] - Simplify. NFC.
llvm-svn: 316163
2017-10-19 15:03:59 +00:00
George Rimar a4ca931336 [ELF] - Remove excessive helper. NFC.
Removes addRegular() helper that looks excessive from Writer.cpp.

Differential revision: https://reviews.llvm.org/D39006

llvm-svn: 316068
2017-10-18 08:36:47 +00:00
George Rimar d30bd1321f [ELF] - Simplify. NFC.
llvm-svn: 316002
2017-10-17 14:31:29 +00:00
Bob Haarman 4f5c8c29ac [lld] Move Threads to Common
Summary:
This will allow using the functionality from other linkers. It is also
a prerequisite for sharing the error logging code.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: emaste, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D38822

llvm-svn: 315725
2017-10-13 18:22:55 +00:00
Rui Ueyama 662bb00028 Hide SymbolBody::IsLocal.
IsLocal member is initialized by the constructor and will never change.
So we don't want to make it directly accessible.

llvm-svn: 315667
2017-10-13 03:37:26 +00:00
Rui Ueyama 5908c2f877 Rename processCommands -> processSectionCommands.
llvm-svn: 315415
2017-10-11 02:28:28 +00:00
Rui Ueyama 6b394caaf1 Rename Commands -> SectionCommands.
"Commands" was ambiguous because in the linker script, everything is
a command. We used to handle only SECTIONS commands, and at the time,
it might make sense to call them the commands, but it is no longer
the case. We handle not only SECTIONS but also MEMORY, PHDRS, VERSION,
etc., and they are all commands.

llvm-svn: 315409
2017-10-11 01:50:56 +00:00
Rui Ueyama a323e2a722 Rename HasSections -> HasSectionsComand.
HasSections is true if there is at least one SECTIONS linker
script command, and it is not directly related to whether we have
section objects or not. So I think the new name is better.

llvm-svn: 315405
2017-10-11 01:34:51 +00:00
Rui Ueyama ac27de9dc7 Remove ScriptConfiguration class and move the members to LinkerScript class.
ScriptConfiguration was a class to contain parsed results of
linker scripts. LinkerScript is a class to interpret it.

That ditinction was needed because we haven't instantiated
LinkerScript early (because, IIRC, LinkerScript class was a
ELFT template function). So, when we parse linker scripts,
we couldn't directly store the result to a LinkerScript instance.

Now, that limitation is gone. We instantiate LinkerScript
at the very beginning of our main function. We can directly
store parse results to a LinkerScript instance.

llvm-svn: 315403
2017-10-11 01:19:33 +00:00
Rafael Espindola 97c57b9e7b Don't create a dummy __tls_get_addr.
We just don't need one with the current setup.

We only error on undefined references that are used by some
relocation.

If we managed to relax all uses of __tls_get_addr, no relocation uses
it and we don't produce an error.

This is less code and fixes the case were we fail to relax. Before we
would produce a broken output, but now we produce an error.

llvm-svn: 315334
2017-10-10 17:27:34 +00:00