Commit Graph

5023 Commits

Author SHA1 Message Date
Rui Ueyama 90f13ed0e4 Return early. NFC.
llvm-svn: 329126
2018-04-03 22:39:12 +00:00
Rui Ueyama d35b839c3f Merge two `if`s and add a few blank lines. NFC.
llvm-svn: 329125
2018-04-03 22:39:04 +00:00
Rafael Espindola 6cd7af51e1 Inline initOffsetMap.
In the lld perf builder r328686 had a negative impact in
stalled-cycles-frontend. Somehow that stat is not showing on my
machine, but the attached patch shows an improvement on cache-misses,
which is probably a reasonable proxy.

My working theory is that given a large input the pieces vector is out
of cache by the time initOffsetMap runs.

Both finalizeContents implementation have a convenient location for
initializing the OffsetMap, so this seems the best solution.

llvm-svn: 329117
2018-04-03 21:38:18 +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
Rui Ueyama 61b67abe89 Fix buildbots.
r329092 broke buildbots.

llvm-svn: 329103
2018-04-03 18:59:31 +00:00
Rui Ueyama cc013f62c1 Make fetchIfLazy only fetch an object file. NFC.
Previously, fetchIfLazy did more than the name says. Now, setting
to UsedInRegularObj is moved to another function.

llvm-svn: 329092
2018-04-03 18:01:18 +00:00
Bob Haarman 8c63bafdd3 [lld] fix data race in ELF/ICF.cpp
Summary:
r328610 fixed a data race in the COFF linker. This change makes a
similar fix to the ELF linker.

Reviewers: ruiu, pcc, rnk

Reviewed By: ruiu

Subscribers: emaste, llvm-commits, arichardson

Differential Revision: https://reviews.llvm.org/D45192

llvm-svn: 329088
2018-04-03 17:27:39 +00:00
George Rimar 1ef746ba21 [ELF] - Eliminate Lazy class.
Patch removes Lazy class which
is just an excessive layer.

Differential revision: https://reviews.llvm.org/D45083

llvm-svn: 329086
2018-04-03 17:16:52 +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
George Rimar bc1d58a6b1 [ELF] - Relax checks for R_386_8/R_386_16 relocations.
This fixes PR36927.

The issue is next. Imagine we have -Ttext 0x7c and code below.

.code16
.global _start
_start:
movb $_start+0x83,%ah

So we have R_386_8 relocation and _start at 0x7C.
Addend is 0x83 == 131. We will sign extend it to 0xffffffffffffff83.

Now, 0xffffffffffffff83 + 0x7c gives us 0xFFFFFFFFFFFFFFFF.
Techically 0x83 + 0x7c == 0xFF, we do not exceed 1 byte value, but
currently LLD errors out, because we use checkUInt<8>.

Let's try to use checkInt<8> now and the following code to see if it can help (no):
main.s:
.byte foo

input.s:
.globl foo
.hidden foo
foo = 0xff

Here, foo is 0xFF. And addend is 0x0. Final value is 0x00000000000000FF.
Again, it fits one byte well, but with checkInt<8>,
we would error out it, so we can't use it.

What we want to do is to check that the result fits 1 byte well.
Patch changes the check to checkIntUInt to fix the issue.

Differential revision: https://reviews.llvm.org/D45051

llvm-svn: 329061
2018-04-03 12:19:04 +00:00
George Rimar bfbeecdc5d [ELF] - Simplify createFiles. NFCI.
Groups paired options together.

Differential revision: https://reviews.llvm.org/D45090

llvm-svn: 329060
2018-04-03 12:06:29 +00:00
George Rimar c6735c23d2 [ELF] - X86_64: don't allow 8/16 bit dynamic relocations.
Having 8/16 bits dynamic relocations is incorrect.

Both gold and bfd (built from latest sources) disallow
that too.

Differential revision: https://reviews.llvm.org/D45158

llvm-svn: 329059
2018-04-03 11:58:23 +00:00
George Rimar 624e163f53 [ELF] - Remove dead declaration. NFC.
llvm-svn: 329058
2018-04-03 10:40:39 +00:00
Rafael Espindola 95f8d303ab Use OffsetMap in getSectionPiece.
OffsetMap maps to a SectionPiece index, but we were not taking
advantage of that in getSectionPiece.

With this patch both getOffset and getSectionPiece use OffsetMap and
the binary search is moved to findSectionPiece.

llvm-svn: 329044
2018-04-03 04:06:14 +00:00
Rui Ueyama 24a47201fd Merge LazyArchive::fetch() and ArchiveFile::getMember(). NFC.
They are to pull out an object file for a symbol, but for a historical
reason the code is written in two separate functions. This patch
merges them.

llvm-svn: 329039
2018-04-03 02:06:57 +00:00
Rui Ueyama 7d6131a898 Inline two trivial functions that are called only once. NFC.
llvm-svn: 329034
2018-04-02 23:58:50 +00:00
Rafael Espindola 3e7d6fc2c6 Define TrapInst for ppc64.
This is nice for testing since it is the first TrapInst whose bytes
are not all the same.

llvm-svn: 329014
2018-04-02 21:11:13 +00:00
Sean Fertile 227d4399bf [PPC64] Minor changes for Plt relocations.
The Plt relative relocations are R_PPC64_JMP_SLOT in the V2 abi, and we only
reserve 2 double words instead of 3 at the start of the array of PLT entries for
lazy linking.

Differential Revision: https://reviews.llvm.org/D44951

llvm-svn: 329006
2018-04-02 19:47:21 +00:00
Sean Fertile af95629deb [PPC64] Write plt stubs for ElfV2 abi
Add the default version of a plt stub for the V2 Elf abi.

Differential Revision: https://reviews.llvm.org/D44850

llvm-svn: 329004
2018-04-02 19:17:12 +00:00
Fangrui Song ef61d85fc9 [ELF] Simplify read32. NFC
llvm-svn: 328908
2018-03-30 23:13:00 +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
Peter Collingbourne 5e3ee94562 ELF: Try to create last thunk section at ThunkSectionSpacing bytes before the end.
Now that we have the ability to create short thunks, it is beneficial
for thunk sections to be surrounded by ThunkSectionSpacing bytes
of code on both sides in order to increase the likelihood that the
distance from the thunk to the target will be sufficiently small to
allow for the creation of a short thunk. This is currently the case
for most thunks that we create, except for the last one, which could,
depending on the size of the output section, potentially appear near
the end and therefore have a relatively small amount of code after it.

This patch moves the last thunk section to ThunkSectionSpacing bytes
before the end of the output section, as long as the section is larger
than 2*ThunkSectionSpacing bytes. It reduces the size of Chromium
for Android's .text section by 32KB.

Differential Revision: https://reviews.llvm.org/D44966

llvm-svn: 328889
2018-03-30 18:32:24 +00:00
Rui Ueyama 5aab635e10 Improve error message for an unknown --plugin-opt.
Before:

  $ ld.lld --plugin-opt=-foo
  ld.lld: --Unknown command line argument '-abc'

After:

  $ ld.lld --plugin-opt=-foo
  ld.lld: --plugin-opt: ld.lld --Unknown command line argument '-abc'

Differential Revision: https://reviews.llvm.org/D45075

llvm-svn: 328880
2018-03-30 17:22:44 +00:00
Rui Ueyama 5a67a6ec4a Re-implement --just-symbols as a regular object file.
I tried a few different designs to find a way to implement it without
too much hassle and settled down with this. Unlike before, object files
given as arguments for --just-symbols are handled as object files, with
an exception that their section tables are handled as if they were all
null.

Differential Revision: https://reviews.llvm.org/D42025

llvm-svn: 328852
2018-03-30 01:15:36 +00:00
Peter Collingbourne 015d30c807 ELF: Add support for short thunks on ARM.
A short thunk uses a direct branch (b or b.w) instruction, and is used
when the target has the same thumbness as the thunk and is within
direct branch range (32MB for ARM, 16MB for Thumb-2). Reduces the
size of Chromium for Android's .text section by around 160KB.

Differential Revision: https://reviews.llvm.org/D44963

llvm-svn: 328846
2018-03-29 22:43:52 +00:00
Rui Ueyama f001ead490 Do not use template for check{Int,UInt,IntUInt,Alignment}.
Template is just unnecessary.

Differential Revision: https://reviews.llvm.org/D45063

llvm-svn: 328843
2018-03-29 22:40:52 +00:00
Peter Collingbourne c5391ce51e ELF: Allow thunks to change size. NFCI.
Differential Revision: https://reviews.llvm.org/D44962

llvm-svn: 328841
2018-03-29 22:32:13 +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
Andrew Ng fe1d346f99 [ELF] Fix X86 & X86_64 PLT retpoline padding
The PLT retpoline support for X86 and X86_64 did not include the padding
when writing the header and entries. This issue was revealed when linker
scripts were used, as this disables the built-in behaviour of filling
the last page of executable segments with trap instructions. This
particular behaviour was hiding the missing padding.

Added retpoline tests with linker scripts.

Differential Revision: https://reviews.llvm.org/D44682

llvm-svn: 328777
2018-03-29 14:03:01 +00:00
Rui Ueyama efe9af9f07 Rename NonLocal -> Global.
NonLocal is technically more accurate, but we already use the term
"Global" to specify the non-local part of the symbol table, and
Local <-> Global is easier to digest.

llvm-svn: 328740
2018-03-28 22:55:40 +00:00
Rui Ueyama 6a1ca2627a Move code so that the code matches with a comment. NFC.
llvm-svn: 328739
2018-03-28 22:47:53 +00:00
Rafael Espindola c8f774b393 Strip @VER suffices from the LTO output.
This fixes pr36623.

The problem is that we have to parse versions out of names before LTO
so that LTO can use that information.

When we get the LTO produced .o files, we replace the previous symbols
with the LTO produced ones, but they still have @ in their names.

We could just trim the name directly, but calling parseSymbolVersion
to do it is simpler.

llvm-svn: 328738
2018-03-28 22:45:39 +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
Peter Collingbourne cebab4a639 ELF: Make required Thunk methods pure virtual and remove an unused argument. NFC.
Also make certain Thunk methods non-const as this will be required for
an upcoming change.

Differential Revision: https://reviews.llvm.org/D44961

llvm-svn: 328732
2018-03-28 21:33:31 +00:00
George Rimar fd11560f6e [ELF] - Linkerscript: support MIN and MAX.
Sample for the OVERLAY command from the spec 
(https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/sections.html)
uses MAX command that we do not support currently:

. = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));

This patch implements support for MIN and MAX.

Differential revision: https://reviews.llvm.org/D44734

llvm-svn: 328696
2018-03-28 11:33:00 +00:00
Rafael Espindola 816127ea17 Initialize OffsetMap in a known location.
This is a small optimization and avoids the need to use call_once.

llvm-svn: 328686
2018-03-28 03:20:18 +00:00
Rafael Espindola 92eba0e14a Define a trivial method inline.
llvm-svn: 328685
2018-03-28 03:14:11 +00:00
Rafael Espindola 5a7ca96e2d Store live offsets as uint32_t.
We don't support input merge sections larger than 4gb, so these can be
uint32_t.

llvm-svn: 328684
2018-03-28 02:32:31 +00:00
Rafael Espindola 35aad41c1b Force SHF_MERGE optimizations with -r.
Some tools (dwarfdump for example) get confused by the current -O0 -r
output since it has multiple copies of .debug_str.

We cannot just merge sections with the same name as they can have
different sh_entsize.

We could have duplicated logic for merging sections based on name and
sh_entsize, but it seems better to just use the existing logic by
enabling optimizations.

llvm-svn: 328640
2018-03-27 17:09:23 +00:00
Andrew Ng ae0a7735b9 [ELF] Disable ICF for synthetic sections
The Data member of synthetic section's is not valid and empty. The Data
member is required to be valid by ICF as it is used by ICF to determine
the equality of section contents. Therefore, exclude synthetic sections
from ICF.

Fixes bug PR36910.

Differential Revision: https://reviews.llvm.org/D44923

llvm-svn: 328624
2018-03-27 14:10:07 +00:00
Rui Ueyama bc0d3b4e0f Remove extraneous local variable. NFC.
llvm-svn: 328605
2018-03-27 02:53:08 +00:00
Rui Ueyama b3e2f74517 Update comments.
llvm-svn: 328604
2018-03-27 02:52:58 +00:00
Rui Ueyama b391288af7 Refactor SharedFile::parseRest. NFC.
SharedFile::parseRest function grew organically and got a bit hard to
understand. This patch refactor it. This patch also adds comments.

Differential Revision: https://reviews.llvm.org/D44860

llvm-svn: 328579
2018-03-26 19:57:38 +00:00
Rafael Espindola 9c2c938521 Reduce code duplication a bit.
Thanks to George Rimar for pointing it out.

llvm-svn: 328571
2018-03-26 18:55:33 +00:00
Rafael Espindola f065390f6c Reduce code duplication a bit. NFC
llvm-svn: 328569
2018-03-26 18:49:31 +00:00
Zaara Syeda c65ae14766 [ELF] GotSection increment NumEntries when Target saves GlobalOffsetTable in the .got
When the target saves ElfSym::GlobalOffsetTable in the .got rather than
.got.plt, Target->GotHeaderEntriesNum states the number of extra entries
required in the .got. Rather than having to add Target->GotHeaderEntriesNum to
NumEntries in every function which refers to NumEntries, this patch changes the
initial value of NumEntries in the constructor.

Differential Revision: https://reviews.llvm.org/D44744

llvm-svn: 328559
2018-03-26 17:50:52 +00:00
George Rimar a6ce78ece1 This is PR36799.
Currently, we might have a bug with scripts like below:

.foo : ALIGN(8) 
{
  *(.foo)
} > ram
because do not expand the memory region when doing ALIGN.

This might result in file range overlaps. The patch fixes the issue.

Differential revision: https://reviews.llvm.org/D44730

llvm-svn: 328479
2018-03-26 08:58:16 +00:00
George Rimar d8281379f9 [ELF] - Do not ignore discarding of .rela.plt/.rela.dyn, allow doing custom layout for them.
Currently when we build input sections list in linker script
we ignore all rel[a] sections. That was done to support
scripts like .rela.dyn : { *(.rela.data) } for emit relocs.

Though as a result following scripts were also silently ignored:

/DISCARD/ : { *(.rela.plt)
/DISCARD/ : { *(.rela.dyn)

and we produced output with this sections. That is not ideal.
The solution this patch suggests is simple: do not ignore synthetic
rel[a] sections. That way we can enable common discarding logic
for them and report a proper error.

Differential revision: https://reviews.llvm.org/D41640

llvm-svn: 328419
2018-03-24 13:10:19 +00:00
Rafael Espindola 4f058a2c6b Add a SectionBase::getVA helper. NFC.
There were a few too many places duplicating this.

llvm-svn: 328402
2018-03-24 00:35:11 +00:00
Rui Ueyama d37c33aff2 Do not add a dummy entry to SharedFile::Verdefs. NFC.
Previously, we used 0 as an alias for VER_NDX_GLOBAL and had a dummy
entry in SharedFile::Verdefs so that the access to the array is within
its boundary. But that's not straightforwad. We can just stop doing both.

llvm-svn: 328401
2018-03-24 00:25:24 +00:00
Rafael Espindola 4bb482eeac Move a Repl access.
Since SectionBase::getOutputSection handles ICF replaces and
SectionBase::getOffset was handling it in some cases, it is more
consistent to have getOffset always handle it.

llvm-svn: 328391
2018-03-23 23:55:49 +00:00
Rafael Espindola 4e82a9e2fa Drop redundant ->Repl.
SectionBase::getOutputSection handles replacement sections, so this
code doesn't have to.

llvm-svn: 328390
2018-03-23 23:53:01 +00:00
Rui Ueyama bd63adcb26 Remove "FIXME" from a comment.
A bug in BFD linker is not our FIXME item.

llvm-svn: 328381
2018-03-23 22:48:17 +00:00
Rafael Espindola 4376cffb57 Add a minimal fix for PR36878.
When looking for the output section and the output offset the
expectation was that the caller had looked at Repl. That works fine
for InputSections, but in the case of MergeInputSections the caller
doesn't have the section that is actually replaced.

The original testcase was failing because getOutputSection was
returning null. The slightly extended testcase also checks that
getOffset also checks Repl.

I will send a refactoring separetelly.

llvm-svn: 328332
2018-03-23 17:19:18 +00:00
George Rimar 16f11462ce [ELF] - Simplify. NFC.
llvm-svn: 328319
2018-03-23 14:43:51 +00:00
George Rimar 54634f1990 [ELF] - Another fix for "LLD crashes with --emit-relocs when trying to proccess .eh_frame"
This fixes PR36367 which is about segfault when --emit-relocs is
used together with .eh_frame sections which happens because
of reordering of regular and .rel[a] sections.

Path changes loop that iterates over input sections to create
relocation target sections first.

Differential revision: https://reviews.llvm.org/D44679

llvm-svn: 328299
2018-03-23 09:18:31 +00:00
Rafael Espindola 85e77b26be Fix the MSVC build.
llvm-svn: 328285
2018-03-23 00:42:47 +00:00
Rafael Espindola 3c3ebcc5f4 Fix PR36793.
With this patch lld will iterate over compile units to find the line
tables instead of assuming there is only one at offset 0.

llvm-svn: 328284
2018-03-23 00:35:27 +00:00
George Rimar 42c939c6c1 [ELF] - Apply clang-format. NFC.
llvm-svn: 328195
2018-03-22 13:47:56 +00:00
Rafael Espindola c08e5afb7c Replace a std::pair with a struct.
This is more readable and should reduce the noise in a followup patch.

llvm-svn: 328164
2018-03-21 22:32:17 +00:00
Zaara Syeda 5dd6bd9631 [ELF][PPC64] Fix getRelExpr for R_PPC64_REL16_LO and R_PPC64_REL16_HA
The relocations R_PPC64_REL16_LO and R_PPC64_REL16_HA should return R_PC
for getRelExpr since they compute #lo(S + A – P) and #ha(S + A – P).

Differential Revision: https://reviews.llvm.org/D44648

llvm-svn: 328103
2018-03-21 15:04:04 +00:00
George Rimar 89481f363a [ELF] - Teach LLD to hint about -fdebug-types-section.
Patch teaches LLD to hint user about -fdebug-types-section flag
if relocation overflow happens in debug section.

Differential revision: https://reviews.llvm.org/D40954

llvm-svn: 328081
2018-03-21 09:19:34 +00:00
Eric Christopher 7baac21bce Fix consitent -> consistent.
llvm-svn: 328010
2018-03-20 18:10:30 +00:00
Fangrui Song 0e30731a6a [ELF] Simplify compCtors and writeInt.
Reviewers: ruiu

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D44690

llvm-svn: 328009
2018-03-20 18:07:25 +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
Rui Ueyama ba32e739b2 Remove GnuHashTableSection::getShift2().
Choosing a Shift2 value based on wordsize is cargo-culted from gold.
Assuming that djb hash is a good hash function, choosing bits [4,9]
shouldn't be any worse or better than choosing bits [5,10]. We shouldn't
have copied that behavior that we can't justify in the first place.

Differential Revision: https://reviews.llvm.org/D44547

llvm-svn: 327921
2018-03-19 23:04:13 +00:00
Rui Ueyama 048a669b92 allow-multiple-definitions should completely suppress errors instead of making them warnings.
We found that when you pass --allow-multiple-definitions or `-z muldefs`
to GNU linkers, they don't complain about duplicate symbols at all. They
don't even print out warnings on it. We emit warnings in that case.
If you pass --fatal-warnings, that difference results in a link failure.

Differential Revision: https://reviews.llvm.org/D44549

llvm-svn: 327920
2018-03-19 23:04:04 +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 aa92fca83c Fix linker script operator precedence.
"&" should have higher priority than "|" [1]. Previously, they had
the same priority.

[1] https://sourceware.org/binutils/docs/ld/Operators.html

Differential Revision: https://reviews.llvm.org/D43880

llvm-svn: 327684
2018-03-15 23:12:33 +00:00
Rui Ueyama 8e53917a26 Add a comment about ELF spec and the symbol table's sh_info.
llvm-svn: 327645
2018-03-15 17:10:50 +00:00
George Rimar 211e94d666 [ELF] - Fix build bot after rL327612.
Missed this one.

llvm-svn: 327616
2018-03-15 09:40:25 +00:00
George Rimar 61a1f50b39 [ELF] - Fix build bot after rL327612.
Error was: 
error: field 'Size' will be initialized after field 'CommandString' [-Werror,-Wreorder]

llvm-svn: 327613
2018-03-15 09:24:51 +00:00
George Rimar 84bcabcb86 [ELF] - Show data and assignment commands in the map file.
Patch teaches LLD to print BYTE/SHORT/LONG/QUAD and
location move commands to the map file.

Differential revision: https://reviews.llvm.org/D44004

llvm-svn: 327612
2018-03-15 09:16:40 +00:00
Rumeet Dhindsa 14c3a871be Update Error Message
Summary: Updates error message  for dynamic relocation attempt for read only segments.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: emaste, javed.absar, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D44453

llvm-svn: 327584
2018-03-14 22:05:12 +00:00
Rui Ueyama a5c1ed340f [ELF] Add .eh_frame pieces to map file
This patch is a simplified version of https://reviews.llvm.org/D42960
written by Andrew Ng.

Differential Revision: https://reviews.llvm.org/D44168

llvm-svn: 327574
2018-03-14 21:18:18 +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
Rui Ueyama 4e6b822cdc Separate sentences to clarify a comment.
llvm-svn: 327555
2018-03-14 19:01:00 +00:00
Rafael Espindola e2cc92ce28 Error instead of producing broken binary.
This "fixes" PR36678 by just producing an error when we find a case
where we would produce an plt entry that used ebx but ebx would not be
set.

llvm-svn: 327542
2018-03-14 18:08:33 +00:00
Rafael Espindola 74acdfa691 Reduce code duplication a bit.
The code for computing the offset of an entry in the plt is simple,
but it was duplicated in quite a few places.

llvm-svn: 327536
2018-03-14 17:41:34 +00:00
George Rimar 2ab9362bf5 [ELF] - Never create .gnu_hash with NBuckets == 0.
Currently, we can end up with NBuckets==0 and android loader
does not like it (PR36537).

Seems we can go with a minimal amount of changes here for simplicity
and be consistent with gold and so just always use >= 1 value for NBuckets.

Differential revision: https://reviews.llvm.org/D44422

llvm-svn: 327481
2018-03-14 08:52:39 +00:00
George Rimar 796684b451 [ELF] - Implement INSERT BEFORE.
This finishes PR35877.

INSERT BEFORE used similar to INSERT AFTER,
it inserts sections before the given target section.

Differential revision: https://reviews.llvm.org/D44380

llvm-svn: 327378
2018-03-13 09:18:11 +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
George Rimar afbf90aef9 [ELF] - Drop special flags for empty output sections.
This fixes PR36598.

LLD currently crashes when we have empty output section
with SHF_LINK_ORDER flag. This might happen if we place an 
empty synthetic section in the linker script, but keep output
section alive with the use of additional symbol, for example.

The patch fixes the issue by dropping all special flags
for empty sections.

Differential revision: https://reviews.llvm.org/D44376

llvm-svn: 327374
2018-03-13 08:32:56 +00:00
George Rimar 59ebd4adf0 [ELF] - Formatted comment, fixed mistype. NFC.
llvm-svn: 327280
2018-03-12 15:18:35 +00:00
George Rimar 0984cfa9ab [ELF] - Removed excessive lookup. NFC.
llvm-svn: 327272
2018-03-12 14:15:38 +00:00
George Rimar e3f198d58a [ELF] - Change consume()->expect() in INSERT AFTER parsing.
AFTER keyword is mandatory and consume() was 
used by mistake here. We accepted broken script before
this patch, testcase shows the issue.

llvm-svn: 327260
2018-03-12 12:34:43 +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
Fangrui Song 17208f1ef9 [ELF] Add elf64lppc emulation.
Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D44264

llvm-svn: 327177
2018-03-09 22:11:46 +00:00
Fangrui Song 0c483024e4 [ELF] Convert {read,write}*be to endianness-aware read/write.
Subscribers: emaste, nemanjai, arichardson, kbarton, llvm-commits

Differential Revision: https://reviews.llvm.org/D44227

llvm-svn: 327156
2018-03-09 18:03:22 +00:00
Peter Collingbourne 04ff122632 ELF: Do not create multiple thunks for the same virtual address.
This avoids creating multiple thunks for symbols with aliases or which
belong to ICF'd sections. This patch reduces the size of Chromium for
Android by 260KB (0.8% of .text).

Differential Revision: https://reviews.llvm.org/D44284

llvm-svn: 327154
2018-03-09 17:54:43 +00:00
George Rimar 1136ec64e8 [ELF] - Fix crash relative to SHF_LINK_ORDER sections.
Our code assumes all input sections in an output SHF_LINK_ORDER
section has SHF_LINK_ORDER flag. We do not check that and that can cause a crash.

That happens because we call 
std::stable_sort(Sections.begin(), Sections.end(), compareByFilePosition);, 
where compareByFilePosition predicate does not expect to see
null when calls getLinkOrderDep. 

The same might happen when sections refer to non-regular sections. 
Test cases demonstrate the issues, patch fixes them.

Differential revision: https://reviews.llvm.org/D44193

llvm-svn: 327006
2018-03-08 15:06:58 +00:00
George Rimar 9e2c8a9db1 [ELF] - Support "INSERT AFTER" statement.
This implements INSERT AFTER in a following way:

During reading scripts it collects all insert statements.
After we done and read all files it inserts statements into script commands list.

With that:
* Rest of code does know nothing about INSERT.
* Approach is straightforward and have no visible limitations.
* It is also easy to support INSERT BEFORE (was seen in clang code once).
* Should work for PR35877 and similar cases.

Cons:
* It assumes we have "main" scripts that describes sections.

Differential revision: https://reviews.llvm.org/D43468

llvm-svn: 327003
2018-03-08 14:54:38 +00:00
Rui Ueyama e66d7a798f Return early. NFC.
We don't need to handle an object file having more than one symbol table,
so as soon as we find the first one, we can process it and then return
from the function.

llvm-svn: 326977
2018-03-08 01:22:30 +00:00
Rui Ueyama c13d858b6d Simplify LazyobjFile and readElfSymbols.
addElfSymbols and readJustSymbolsFile still has duplicate code, but
I didn't come up with a good idea to eliminate them. Since this patch
is an improvement, I'm sending this for review.

Differential Revision: https://reviews.llvm.org/D44187

llvm-svn: 326972
2018-03-08 01:05:58 +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
Rui Ueyama 5aa2db1e12 Initialize a member in C++11 style. NFC.
llvm-svn: 326933
2018-03-07 19:25:27 +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 e1847da924 Rename Indent{1,2} -> Indent{8,16}.
llvm-svn: 326912
2018-03-07 17:15:15 +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
James Henderson cb4c19f315 [ELF] Prevent crash when reporting errors if debug line cannot be parsed
LLD uses the debug info and debug line sections to determine the location of
e.g. references to undefined symbols, when producing error messages. In the
event that debug info was present, but debug line parsing failed for some
reason, then a nullptr would end up being dereferenced by the location-lookup
code.

Differential Revision: https://reviews.llvm.org/D44205

Reviewers: grimar
llvm-svn: 326899
2018-03-07 15:22:58 +00:00
George Rimar 527bfd7a48 [ELF] - Recommit r326892,r326893 "[ELF] - Report LMA region overflows."
With fix: add missing "RUN:" prefix to test case.

Original commit message:
We do not report LMA region overflows currently.
Both GNU linkers do that. The patch implements it.

Differential revision: https://reviews.llvm.org/D44094

llvm-svn: 326895
2018-03-07 12:44:18 +00:00
George Rimar 06846c2251 [ELF] - Revert r326892, r326893.
Bots are still unhappy:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/26259

llvm-svn: 326894
2018-03-07 12:33:00 +00:00
George Rimar 97e054e00d [ELF] - Report LMA region overflows.
We do not report LMA region overflows currently.
Both GNU linkers do that. The patch implements it.

Differential revision: https://reviews.llvm.org/D44094

llvm-svn: 326892
2018-03-07 11:54:30 +00:00
George Rimar 54baa5f45f [ELF] - Allow discarding .hash and .gnu.hash from linker script.
Currently, LLD segfaults when linker script attempts to discard
one of the hash sections. This patch fixes that.

Differential revision: https://reviews.llvm.org/D44012

llvm-svn: 326891
2018-03-07 11:47:15 +00:00
Rui Ueyama 9e0171fbb6 Do not create temporary strings just to print out spaces. NFC.
llvm-svn: 326841
2018-03-06 22:48:46 +00:00
Rui Ueyama 09fcd4c34c Implement --just-symbols.
Differential Revision: https://reviews.llvm.org/D39348

llvm-svn: 326835
2018-03-06 21:25:37 +00:00
Rafael Espindola ddb33c0961 Improve duplicated version handling.
It looks like the problem that caused us to originally warn instead of
error was that of a symbol being assigned to the same version twice.

Now we don't warn if a symbol is assigned to the same version twice,
but error if it is assigned to multiple.

This fixes pr28342.

llvm-svn: 326813
2018-03-06 17:05:12 +00:00
Rui Ueyama 067617f9ba Remove redundant casts.
llvm-svn: 326753
2018-03-05 23:50:45 +00:00
George Rimar 162d436c8e [ELF] - Support moving location counter when MEMORY is used.
We do not expand memory region correctly for following scripts:

.foo.1 : 
 {
   *(.foo.1)
   . += 0x1000;
 } > ram
Patch generalizes expanding of output sections and memory
regions in one place and fixes the issue.

Differential revision: https://reviews.llvm.org/D43999

llvm-svn: 326688
2018-03-05 10:54:03 +00:00
George Rimar 7b91e2133e [ELF] - Report location for div/mod by zero.
"division by zero" or "modulo by zero" are not
very informative errors and even probably confusing
as does not let to know that error is coming from linker script.
Patch adds location reporting.

Differential revision: https://reviews.llvm.org/D43934

llvm-svn: 326686
2018-03-05 10:02:44 +00:00
Rafael Espindola e3a6062844 Simplify. NFC.
Since r321982 we don't set VersionId in scanShlibUndefined, which
makes InVersionScript redundant.

llvm-svn: 326641
2018-03-03 02:13:50 +00:00
George Rimar 97785af464 [ELF] - Report error when memory region is overflowed by data commands.
LLD can not catch a memory area overflow when using a data command.
If we have the script below:

.foo : 
{
  *(.foo)
  BYTE(0x1)
} > ram

where BYTE overflows the ram region, we do not report it currently.
Patch fixes that.

Differential revision: https://reviews.llvm.org/D43948

llvm-svn: 326545
2018-03-02 08:11:58 +00:00
Rui Ueyama 036ed36f0a Accept both `--foo bar` and `--foo=bar` styles options.
GNU linkers by convention supports both `--foo bar` and `--foo=bar` styles
for all long options that take arguments.

Differential Revision: https://reviews.llvm.org/D43972

llvm-svn: 326506
2018-03-01 23:06:10 +00:00
Rui Ueyama 7c18abf99a Set DF_TEXTREL to executables that need text relocations.
Summary:
If an executable needs text relocations, it should be marked as such so
that the loader can prepare for text relocations. We currently create a
dummy segment with DT_TEXTREL for that purpose.

Generic ABI as of 2000 [1] mentioned that "Its [DT_TEXTREL's] use
has been superseded by the DF_TEXTREL flag". However, it's actually not
superseded even after 18 years. OpenBSD and musl recognize only DT_TEXTREL.
So we still need to set both.

[1] http://www.sco.com/developers/gabi/2000-07-17/ch5.dynamic.html

Reviewers: rafael

Subscribers: emaste, llvm-commits, arichardson

Differential Revision: https://reviews.llvm.org/D43920

llvm-svn: 326503
2018-03-01 22:56:52 +00:00
Rafael Espindola 2e4bcb0095 Don't ingoned --enable-new-dtags.
llvm-svn: 326498
2018-03-01 22:23:51 +00:00
Rafael Espindola e75b42ee4e Don't allocate a header bellow address 0.
With the current code if the script has a PHDRS we always obey and try
to allocate a header. This can cause Min - HeaderSize to underflow.

It looks like bfd actually prints an error for this case. With this
patch we do the same.

Found while looking at pr36515.

llvm-svn: 326441
2018-03-01 15:25:46 +00:00
George Rimar b068b03793 [ELF] - Don't crash on broken MEMORY declaration.
LLD crashes with broken scripts shown in testcase,
because fails to read memory regon name and accesses
MemoryRegions's element which is nullptr.
Patch fixes it.

Differential revision: https://reviews.llvm.org/D43866

llvm-svn: 326431
2018-03-01 12:36:01 +00:00
George Rimar c4df670dea [ELF] - Do not remove empty sections that use symbols in expressions.
This is PR36515.

Currenly if we have a script like .debug_info 0 : { *(.debug_info) },
we would not remove this section and keep it in the output.
That does not work, because it is common case for
debug sections to have a zero address expression.
Patch changes behavior so that we remove only sections
that do not use symbols in its expressions.

Differential revision: https://reviews.llvm.org/D43863

llvm-svn: 326430
2018-03-01 12:27:04 +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 39ba31ff50 Add "%" operator to the linker script.
This patch improves compatibility with GNU linkers.

Differential Revision: https://reviews.llvm.org/D43883

llvm-svn: 326348
2018-02-28 18:38:13 +00:00
Rui Ueyama 1d20222a48 Inline a trivial function. NFC.
llvm-svn: 326347
2018-02-28 18:25:00 +00:00
Rafael Espindola 367bfce611 Simplify. NFC.
llvm-svn: 326344
2018-02-28 18:05:37 +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
Igor Kudrin c844524e46 [ELF] Process linker scripts deeper when declaring symbols.
We should process symbols inside output section declarations the same way as top-level ones.

Differential Revision: https://reviews.llvm.org/D43008

llvm-svn: 326305
2018-02-28 05:55:56 +00:00
Rui Ueyama f0884e474c Add `--dynamic-linker=foo` as an alias for `--dynamic-linker foo`.
This patch fixes a minor compatibility issue with ld.gold and ld.bfd.

llvm-svn: 326243
2018-02-27 20:37:18 +00:00
Rafael Espindola 3f4c673d38 Put undefined symbols from shared libraries in the symbol table.
With the recent fixes these symbols have more in common than not with
regular undefined symbols.

llvm-svn: 326242
2018-02-27 20:31:22 +00:00
Rafael Espindola b851121130 Fix gcc warning.
Should fix the build in some bots.

llvm-svn: 326209
2018-02-27 17:11:10 +00:00
Rafael Espindola 3bfa8f0120 Add support for SHF_ARM_PURECODE.
Now we don't mark a PT_LOAD as readable if all its sections are
SHF_ARM_PURECODE.

llvm-svn: 326207
2018-02-27 16:55:25 +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
Igor Kudrin 3345c9ac18 [ELF] Create and export symbols provided by a linker script if they referenced by DSOs.
It should be possible to resolve undefined symbols in dynamic libraries
using symbols defined in a linker script.

Differential Revision: https://reviews.llvm.org/D43011

llvm-svn: 326176
2018-02-27 07:18:07 +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
Fangrui Song ffac3ed341 [ELF] Fix IsPreemptible comment and typo. NFC
llvm-svn: 325963
2018-02-23 21:57:49 +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
George Rimar 2d53967b48 Recommit "[ELF] - Do not crash with --emit-relocs and --icf=all together."
Latest patch version now.

Original commit message:

[ELF] - Do not crash with --emit-relocs and --icf=all together.

Previously we would crash because did not mark .rel[a] sections
as dead and they tried to access parent which was not live
after ICF and therefore was null.

Differential revision: https://reviews.llvm.org/D43241

llvm-svn: 325879
2018-02-23 10:37:33 +00:00
George Rimar aa359f87e8 [ELF] - Revert r325877 "[ELF] - Do not crash with --emit-relocs and --icf=all together."
Not latest version of patch was committed by mistake.

llvm-svn: 325878
2018-02-23 10:30:31 +00:00
George Rimar cde84d1cd0 [ELF] - Do not crash with --emit-relocs and --icf=all together.
Previously we would crash because did not mark .rel[a] sections
as dead and they tried to access parent which was not live
after ICF and therefore was null.

Differential revision: https://reviews.llvm.org/D43241

llvm-svn: 325877
2018-02-23 10:27:13 +00:00
George Rimar 3cdf0d969a [ELF] - Report error if removed empty output section declaration used undefined symbols.
This is for fixing PR36297.

Issue itself is that if we have SECTIONS { .bar (a+b) : { *(.stub) } };
script and no section .stub, when LLD will remove .bar, but
produce output with undefined symbols a and b.

Differential revision: https://reviews.llvm.org/D43069

llvm-svn: 325875
2018-02-23 10:15:54 +00:00