Commit Graph

659 Commits

Author SHA1 Message Date
Fangrui Song d6d640ebae [ELF][test] Fix section sh_type and sh_flags
A future MC change may add a warning/error when a .section directive
specifies incorrect sh_flags/sh_type.
2020-02-19 22:01:42 -08:00
Fangrui Song 81cebfd008 [ELF][test] Change -o %t to -o /dev/null if the output is not needed 2020-02-12 21:54:50 -08:00
Sterling Augustine a7ecf4c324 Explicitly state the output file.
Summary:
Even though this test is a check for failure, lld still attempts
to open the final output file, which fails when the default "a.out"
file is used and the current directory is read-only. Specifying an
output file works around this problem.

Reviewers: espindola

Subscribers: emaste, MaskRay, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74523
2020-02-12 21:25:30 -08:00
Fangrui Song 7c426fb1a6 [ELF] Support INSERT [AFTER|BEFORE] for orphan sections
D43468+D44380 added INSERT [AFTER|BEFORE] for non-orphan sections. This patch
makes INSERT work for orphan sections as well.

`SECTIONS {...} INSERT [AFTER|BEFORE] .foo` does not set `hasSectionCommands`, so the result
will be similar to a regular link without a linker script. The differences when `hasSectionCommands` is set include:

* image base is different
* -z noseparate-code/-z noseparate-loadable-segments are unavailable
* some special symbols such as `_end _etext _edata` are not defined

The behavior is similar to GNU ld:
INSERT is not considered an external linker script.

This feature makes the section layout more flexible. It can be used to:

* Place .nv_fatbin before other readonly SHT_PROGBITS sections to mitigate relocation overflows.
* Disturb the layout to expose address sensitive application bugs.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D74375
2020-02-12 08:21:52 -08:00
Fangrui Song b498d99338 [ELF] Start a new PT_LOAD if LMA region is different
GNU ld has a counterintuitive lang_propagate_lma_regions rule.

```
// .foo's LMA region is propagated to .bar because their VMA region is the same,
// and .bar does not have an explicit output section address (addr_tree).
.foo : { *(.foo) } >RAM AT> FLASH
.bar : { *(.bar) } >RAM

// An explicit output section address disables propagation.
.foo : { *(.foo) } >RAM AT> FLASH
.bar . : { *(.bar) } >RAM
```

In both cases, lld thinks .foo's LMA region is propagated and
places .bar in the same PT_LOAD, so lld diverges from GNU ld w.r.t. the
second case (lma-align.test).

This patch changes Writer<ELFT>::createPhdrs to disable propagation
(start a new PT_LOAD). A user of the first case can make linker scripts
portable by explicitly specifying `AT>`. By contrast, there was no
workaround for the old behavior.

This change uncovers another LMA related bug in assignOffsets() where
`ctx->lmaOffset = 0;` was omitted. It caused a spurious "load address
range overlaps" error for at2.test

The new PT_LOAD rule is complex. For convenience, I listed the origins of some subexpressions:

* rL323449: `sec->memRegion == load->firstSec->memRegion`; linkerscript/at3.test
* D43284: `load->lastSec == Out::programHeaders` (don't start a new PT_LOAD after program headers); linkerscript/at4.test
* D58892: `sec != relroEnd` (start a new PT_LOAD after PT_GNU_RELRO)

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D74297
2020-02-12 08:20:14 -08:00
Fangrui Song e21b9ca751 [ELF] Respect output section alignment for AT> (non-null lmaRegion)
When lmaRegion is non-null, respect `sec->alignment`
This rule is analogous to `switchTo(sec)` which advances sh_addr (VMA).

This fixes the p_paddr misalignment issue as reported by
https://android-review.googlesource.com/c/trusty/external/trusted-firmware-a/+/1230058

Note, `sec->alignment` is the maximum of ALIGN and input section alignments. We may overalign LMA than GNU ld.

linkerscript/align-lma.s has a FIXME that demonstrates another bug:
`.bss ... >RAM` should be placed in a different PT_LOAD (GNU ld
behavior) because its lmaRegion (nullptr) is different from the previous
section's lmaRegion (ROM).

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D74286
2020-02-12 08:19:42 -08:00
Fangrui Song 1732f50ee0 [ELF][test] Use llvm-readelf -l instead of llvm-readobj -l for some memory region tests 2020-02-08 22:45:00 -08:00
Thomas Preud'homme c42fe24754 [lld/ELF] PR44498: Support input filename in double quote
Summary:
Linker scripts allow filenames to be put in double quotes to prevent
characters in filenames that are part of the linker script syntax from
having their special meaning. Case in point the * wildcard character.

Availability of double quoting filenames also allows to fix a failure in
ELF/linkerscript/filename-spec.s when the path contain a @ which the
lexer consider as a special characters and thus break up a filename
containing it. This may happens under Jenkins which createspath such as
pipeline@2.

To avoid the need for escaping GlobPattern metacharacters in filename
in double quotes, GlobPattern::create is augmented with a new parameter
to request literal matching instead of relying on the presence of a
wildcard character in the pattern.

Reviewers: jhenderson, MaskRay, evgeny777, espindola, alexshap

Reviewed By: MaskRay

Subscribers: peter.smith, grimar, ruiu, emaste, arichardson, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72517
2020-01-22 12:03:10 +00:00
Kazuaki Ishizaki 7ae3d33546 [lld] Fix trivial typos in comments
Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D72196
2020-01-06 10:25:48 -08:00
Fangrui Song 1edd965130 [ELF] Support input section description .gnu.version* in /DISCARD/
Linux powerpc discards `*(.gnu.version*)` (arch/powerpc/kernel/vmlinux.lds.S)
to suppress --orphan-handling=warn warnings in the -pie output `.tmp_vmlinux1`

The support is simple. Just add isLive() to:

1) Fix an assertion in SectionBase::getPartition() called by VersionTableSection::isNeeded().
2) Suppress DT_VERSYM, DT_VERDEF, DT_VERNEED and DT_VERNEEDNUM, if the relevant section is discarded.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71819
2019-12-26 09:54:22 -08:00
Fangrui Song 345f59667d [ELF] Rename .plt to .iplt and decrease EM_PPC{,64} alignment of .glink to 4
GNU ld creates the synthetic section .iplt, and has a built-in linker
script that assigns .iplt to the output section .plt . There is no
output section named .iplt .

Making .iplt an output section actually has a benefit that makes the
tricky toolchain feature stand out. Symbolizers don't have to deal with
mixed PLT entries (e.g. llvm-objdump -d incorrectly annotates such jump
targets).

On EM_PPC{,64}, .glink contains a PLT resolver and a series of jump
instructions. The 4-byte entry size makes it unnecessary to have an
alignment of 16.

Mark ppc32-gnu-ifunc.s and ppc32-gnu-ifunc-nonpreemptable.s as `XFAIL: *`.
They test IPLT on EM_PPC, which never works.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D71520
2019-12-17 00:15:59 -08:00
Fangrui Song a71c1e2a57 [ELF] Support input section description .rel[a].dyn in /DISCARD/
Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D70695
2019-11-25 21:49:46 -08:00
Fangrui Song 6b0eb5a672 [ELF] Improve --gc-sections compatibility with GNU ld regarding section groups
Based on D70020 by serge-sans-paille.

The ELF spec says:

> Furthermore, there may be internal references among these sections that would not make sense if one of the sections were removed or replaced by a duplicate from another object. Therefore, such groups must be included or omitted from the linked object as a unit. A section cannot be a member of more than one group.

GNU ld has 2 behaviors that we don't have:

- Group members (nextInSectionGroup != nullptr) are subject to garbage collection.
  This includes non-SHF_ALLOC SHT_NOTE sections.
  In particular, discarding non-SHF_ALLOC SHT_NOTE sections is an expected behavior by the Annobin
  project. See
  https://developers.redhat.com/blog/2018/02/20/annobin-storing-information-binaries/
  for more information.
- Groups members are retained or discarded as a unit.
  Members may have internal references that are not expressed as
  SHF_LINK_ORDER, relocations, etc. It seems that we should be more conservative here:
  if a section is marked live, mark all the other member within the
  group.

Both behaviors are reasonable. This patch implements them.

A new field InputSectionBase::nextInSectionGroup tracks the next member
within a group. on ELF64, this increases sizeof(InputSectionBase) froms
144 to 152.

InputSectionBase::dependentSections tracks section dependencies, which
is used by both --gc-sections and /DISCARD/. We can't overload it for
the "next member" semantic, because we should allow /DISCARD/ to discard
sections independent of --gc-sections (GNU ld behavior). This behavior
may be reasonably used by `/DISCARD/ : { *(.ARM.exidx*) }` or `/DISCARD/
: { *(.note*) }` (new test `linkerscript/discard-group.s`).

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D70146
2019-11-19 08:54:06 -08:00
Fangrui Song db8dad20b3 [ELF][test] Change references of %T to %t.dir
Test files in the same directory share the same %T.  %T is easy to
misuse and cause race conditions (when running concurrently) so it has
been deprecated since D48842 (see docs/CommandGuide/lit.rst).

While here, add `rm -rf %t.dir` so that tests cannot depend on old files lying around.

Reviewed By: jhenderson, ruiu

Differential Revision: https://reviews.llvm.org/D69572
2019-10-30 09:22:48 -07:00
Jordan Rupprecht ce88cdf096 [lld][test] Speculative fix for lld+windows failures
This updates some more places using `%T` to use `%/T` for path normalization.

If this does not work, this and r375126 should be reverted together.

llvm-svn: 375131
2019-10-17 16:29:03 +00:00
Jordan Rupprecht 1b6c3ca126 [lld][test] Fix use of escape character in an lld test on Windows
Summary:
Glob support was improved to accept `\` as an escape character in r375051, but reverted as r375052 due to a failure in this test on Windows.

The reason this failure seems Windows specific is because the path separator `\` is currently being relied on to be interpreted literally instead of as an escape character. Per documentation on linker input section wildcard patterns, this seems to be a bug in lld accepting `\` as a literal instead of an escape character.

For example:
```
SECTIONS{ .foo :{ /path/to/foo.o(.foo) }} # OK: standard UNIX path
SECTIONS{ .foo :{ C:/path/to/foo.o(.foo) }} # OK: windows accepts slashes in either direction
SECTIONS{ .foo :{ C:\\path\\to\\foo.o(.foo) }} # OK: escape character used to match a literal \
SECTIONS{ .foo :{ C:\path\to\foo.o(.foo) }} # BAD: this actually matches the path C:pathtofoo.o(.foo)
```

This avoids the problem in the test by using `%/T` in place of `%T` to normalize the path separator to `/`, which windows should also accept.

This patch just fixes the test, and glob support will be be relanded separately.

For a sample buildbot error, see: http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/11578/steps/stage%201%20check/logs/stdio

Reviewers: evgeny777, ruiu, MaskRay, espindola

Reviewed By: ruiu, MaskRay

Subscribers: emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69074

llvm-svn: 375126
2019-10-17 15:35:28 +00:00
George Rimar 938db706fe [LLD][ELF] - Update test cases after llvm-readobj output format change.
The change was:

SHT_GNU_verdef { -> VersionDefinitions [
SHT_GNU_verneed { -> VersionRequirements [
Version symbols [ -> VersionSymbols [
EH_FRAME Header [ -> EHFrameHeader {

llvm-svn: 375096
2019-10-17 10:23:59 +00:00
George Rimar a8346cee8a [LLD][ELF] - Update test cases after llvm-readobj change.
https://reviews.llvm.org/D68704 changed the output format.

llvm-svn: 374542
2019-10-11 12:27:20 +00:00
Fangrui Song f1e1451946 [ELF] Set SectionBase::partition in processSectionCommands
Fixes PR43461 (regression caused by D67504)

The partition field of a SECTIONS-specified section is not set after
D67504. The 0 value affects findSection() which checks if the partition
field is 1.

So `Out::initArray = findSection(".init_array")` is null, and
DT_INIT_ARRAYSZ is not set.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D68087

llvm-svn: 372996
2019-09-26 17:10:09 +00:00
Peter Smith 06b3e3421a [ELF][ARM] Fix crash when discarding InputSections that have .ARM.exidx
When /DISCARD/ is used on an input section, that input section may have
a .ARM.exidx metadata section that depends on it. As the discard handling
comes after the .ARM.exidx synthetic section is created we need to make
sure that we account for the case where the .ARM.exidx output section
should be removed because there are no more live input sections.

Differential Revision: https://reviews.llvm.org/D67848

llvm-svn: 372781
2019-09-24 21:44:14 +00:00
Fangrui Song e47bbd28f8 [ELF] Make MergeInputSection merging aware of output sections
Fixes PR38748

mergeSections() calls getOutputSectionName() to get output section
names. Two MergeInputSections may be merged even if they are made
different by SECTIONS commands.

This patch moves mergeSections() after processSectionCommands() and
addOrphanSections() to fix the issue. The new pass is renamed to
OutputSection::finalizeInputSections().

processSectionCommands() and addorphanSections() are changed to add
sections to InputSectionDescription::sectionBases.

finalizeInputSections() merges MergeInputSections and migrates
`sectionBases` to `sections`.

For the -r case, we drop an optimization that tries keeping sh_entsize
non-zero. This is for the simplicity of addOrphanSections(). The
updated merge-entsize2.s reflects the change.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D67504

llvm-svn: 372734
2019-09-24 11:48:31 +00:00
Fangrui Song d4306e90cb [ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64
Port the D64906 technique to EM_X86_64.

Differential Revision: https://reviews.llvm.org/D67482

llvm-svn: 371958
2019-09-16 07:05:34 +00:00
Fangrui Song 88796a7988 [ELF][test] Improve and reorganize another set of tests
Add file-level comments
Replace trivial Input/*.s with echo ... | llvm-mc
Delete insignificant addresses to make them more tolerant to layout changes
Simplify test output

Merge merge-section-types.s into compatible-section-types.s and add a missed case
Merge gnu-ifunc-gotpcrel.s (added in D19517) into gnu-ifunc-dso.s (added in D35119) and add missed cases
Delete typed-undef.s - covered by executable-undefined-ignoreall.s
Delete emit-relocs-shared.s - covered by emit-relocs-merge.s

Replace copy-rel-pie.s and copy-rel-pie2.s with canonical-plt-pcrel.s, canonical-plt-symbolic.s and copy-rel.s:
add -no-pie cases.
add a case that a canonical PLT can be created for STT_GNU_IFUNC. The logic in Symbols.h was untested:

  // ctor of SharedSymbol
  if (this->type == llvm::ELF::STT_GNU_IFUNC)
    this->type = llvm::ELF::STT_FUNC;

llvm-svn: 371361
2019-09-09 03:35:14 +00:00
Fangrui Song 2682bc3c9d [ELF] Replace error() with errorOrWarn() for the ASSERT command
Summary:
ld.bfd produces an output with --noinhibit-exec when an ASSERT fails.
Use errorOrWarn() so that we can produce an output as well.

An interesting case is that symbol assignments may execute multiple
times, so we probably want to suppress errors for non-final runs.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D67285

llvm-svn: 371225
2019-09-06 16:30:22 +00:00
Fangrui Song 5d9f419a2e Revert "Revert r370635, it caused PR43241."
This reverts commit 50d2dca22b3b05d0ee4883b0cbf93d7d15f241fc.

llvm-svn: 371215
2019-09-06 15:57:24 +00:00
Nico Weber 8455294f2a Revert r370635, it caused PR43241.
llvm-svn: 371202
2019-09-06 13:23:42 +00:00
Fangrui Song d8bc6a48ea [ELF] Do not ICF two sections with different output sections (by SECTIONS commands)
Fixes PR39418. Complements D47241 (the non-linker-script case).

processSectionCommands() assigns input sections to output sections.
ICF is called before it, so .text.foo and .text.bar may be folded even if
their output sections are made different by SECTIONS commands.

```
markLive<ELFT>()
doIcf<ELFT>()                      // During ICF, we don't know the output sections
writeResult()
  combineEhSections<ELFT>()
  script->processSectionCommands() // InputSection -> OutputSection assignment
```

This patch splits processSectionCommands() into processSectionCommands() and
processSymbolAssignments(), and moves processSectionCommands() before ICF:

```
markLive<ELFT>()
combineEhSections<ELFT>()
script->processSectionCommands()
doIcf<ELFT>()                      // should remove folded input sections
writeResult()
  script->processSymbolAssignments()
```

An alternative approach is to unfold a section `sec` in
processSectionCommands() when we find `sec` and `sec->repl` belong to
different output sections. I feel this patch is superior because this
can fold more sections and the decouple of
SectionCommand/SymbolAssignment gives flexibility:

* An ExprValue can't be evaluated before its section is assigned to an
  output section -> we can delete getOutputSectionVA and simplify
  another place where we had to check if the output section is null.
  Moreover, a case in linkerscript/early-assign-symbol.s can be handled
  now.
* processSectionCommands/processSymbolAssignments can be freely moved
  around.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D66717

llvm-svn: 370635
2019-09-02 10:33:58 +00:00
Richard Trieu f837bb4a34 Copy test data so tests don't traverse test directories. NFC
llvm-svn: 369984
2019-08-26 22:41:05 +00:00
Fangrui Song debcac9fef [ELF] Make LinkerScript::assignAddresses iterative
PR42990. For `SECTIONS { b = a; . = 0xff00 + (a >> 8); a = .; }`,
we currently set st_value(a)=0xff00 while st_value(b)=0xffff.

The following call tree demonstrates the problem:

```
link<ELF64LE>(Args);
  Script->declareSymbols(); // insert a and b as absolute Defined
  Writer<ELFT>().run();
    Script->processSectionCommands();
      addSymbol(cmd);       // a and b are re-inserted. LinkerScript::getSymbolValue
                            // is lazily called by subsequent evaluation
    finalizeSections();
      forEachRelSec(scanRelocations<ELFT>);
        processRelocAux     // another problem PR42506, not affected by this patch
      finalizeAddressDependentContent(); // loop executed once
        script->assignAddresses(); // a = 0, b = 0xff00
    script->assignAddresses(); // a = 0xff00, _end = 0xffff
```

We need another assignAddresses() to finalize the value of `a`.

This patch

1) modifies assignAddress() to track the original section/value of each
  symbol and return a symbol whose section/value has changed.
2) moves the post-finalizeSections assignAddress() inside the loop
  of finalizeAddressDependentContent() and makes it iterative.
  Symbol assignment may not converge so we make a few attempts before
  bailing out.

Note, assignAddresses() must be called at least twice. The penultimate
call finalized section addresses while the last finalized symbol values.
It is somewhat obscure and there was no comment.
linkerscript/addr-zero.test tests this.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D66279

llvm-svn: 369889
2019-08-26 10:23:31 +00:00
Fangrui Song af47d0021c [ELF] Align the first section of a PT_LOAD even if its type is SHT_NOBITS
Reported at https://reviews.llvm.org/D64930#1642223

If the only section of a PT_LOAD is a SHT_NOBITS section (e.g. .bss), we
may not align its sh_offset. p_offset of the PT_LOAD will be set to
sh_offset, and we will get p_offset!=p_vaddr (mod p_align).  If such
executable is mapped by the Linux kernel, it will segfault.

After D64906, this may happen the non-linker script case.

The linker script case has had this issue for a long time.
This was fixed by rL321657 (but the test linkerscript/nobits-offset.s
failed to test a SHT_NOBITS section), but broken by rL345154.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D66658

llvm-svn: 369828
2019-08-24 00:41:15 +00:00
Fangrui Song 179dc276eb [ELF] Expand regions for gaps due to explicit address
If the dot gets moved by an explicit section address, an empty gap between sections could be created. The encompassing region for the section being parsed needs to be expanded to include the gap.

Differential Revision: https://reviews.llvm.org/D65722

Patch by Gabriel Smith!

llvm-svn: 368379
2019-08-09 01:25:49 +00:00
Fangrui Song e28a70daf4 [ELF] Consistently prioritize non-* wildcards overs "*" in version scripts
We prioritize non-* wildcards overs VER_NDX_LOCAL/VER_NDX_GLOBAL "*".
This patch generalizes the rule to "*" of other versions and thus fixes PR40176.
I don't feel strongly about this GNU linkers' behavior but the
generalization simplifies code.

Delete `config->defaultSymbolVersion` which was used to special case
VER_NDX_LOCAL/VER_NDX_GLOBAL "*".

In `SymbolTable::scanVersionScript`, custom versions are handled the same
way as VER_NDX_LOCAL/VER_NDX_GLOBAL. So merge
`config->versionScript{Locals,Globals}` into `config->versionDefinitions`.
Overall this seems to simplify the code.

In `SymbolTable::assign{Exact,Wildcard}Versions`,
`sym->verdefIndex == config->defaultSymbolVersion` is changed to
`verdefIndex == UINT32_C(-1)`.
This allows us to give duplicate assignment diagnostics for
`{ global: foo; };` `V1 { global: foo; };`

In test/linkerscript/version-script.s:
  vs_index of an undefined symbol changes from 0 to 1. This doesn't matter (arguably 1 is better because the binding is STB_GLOBAL) because vs_index of an undefined symbol is ignored.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D65716

llvm-svn: 367869
2019-08-05 14:31:39 +00:00
Fangrui Song 25ab1c6471 [ELF] Move R_*_IRELATIVE from .rel[a].plt to .rel[a].dyn unless --pack-dyn-relocs=android[+relr]
An R_*_IRELATIVE represents the address of a STT_GNU_IFUNC symbol
(redirected at runtime) which is non-preemptable and is not associated
with a canonical PLT (associated with a symbol with a section index of
SHN_UNDEF but a non-zero st_value).

.rel[a].plt [DT_JMPREL, DT_JMPREL+DT_JMPRELSZ) contains relocations that
can be lazily resolved. R_*_IRELATIVE are always eagerly resolved, so
conceptually they do not belong to .rela.plt. "iplt" is mostly a misnomer.

glibc powerpc and powerpc64 do not resolve R_*_IRELATIVE if they are in .rela.plt.

    // a.o - synthesized PLT call stub has an R_*_IRELATIVE
    void ifunc(); int main() { ifunc(); }
    // b.o
    static void real() {}
    asm (".type ifunc, %gnu_indirect_function");
    void *ifunc() { return &real; }

The lld-linked executable crashes. ld.bfd places R_*_IRELATIVE in
.rela.dyn and the executable works.

glibc i386, x86_64, and aarch64 have logic
(glibc/sysdeps/*/dl-machine.h:elf_machine_lazy_rel) to eagerly resolve
R_*_IRELATIVE in .rel[a].plt so the lld-linked executable works.

Move R_*_IRELATIVE from .rel[a].plt to .rel[a].dyn to fix the crashes on
glibc powerpc/powerpc64. This also helps simplifying ifunc
implementation in FreeBSD rtld-elf powerpc64.

If --pack-dyn-relocs=android[+relr] is specified, the Android packed
dynamic relocation format is used for .rela.dyn. We cannot name
in.relaIplt ".rela.dyn" because the output section will have mixed
formats. This can be improved in the future.

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D65651

llvm-svn: 367745
2019-08-03 02:26:52 +00:00
George Rimar c44a23f8f4 [LLD][ELF] - Linkerscript: fix FILL() expressions handling.
D64130 introduced a bug described in the following message:
https://reviews.llvm.org/D64130#1571560

The problem can happen with the following script:

SECTIONS {
  .out : {
...
   FILL(0x10101010)
   *(.aaa)
...
}

The current code tries to read (0x10101010) as an expression and
does not break when meets *, what results in a script parsing error.

In this patch, I verify that FILL command's expression always wrapped in ().
And at the same time =<fillexp> expression can be both wrapped or unwrapped.
I checked it matches to bfd/gold.

Differential revision: https://reviews.llvm.org/D64476

llvm-svn: 365635
2019-07-10 14:36:48 +00:00
George Rimar 0810f16fb9 [LLD][ELF] - Linkerscript: add a support for expressions for section's filling
Imagine the script:

.section: {
...
} = FILL_EXPR
LLD assumes that FILL_EXPR is a number, and does not allow
it to be an expression. Though that is allowed by specification:
https://sourceware.org/binutils/docs-2.32/ld/Output-Section-Fill.html

This patch adds a support for cases when FILL_EXPR is simple math expression.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42482.

Differential revision: https://reviews.llvm.org/D64130

llvm-svn: 365143
2019-07-04 14:17:31 +00:00
Igor Kudrin fd0ad4b24d [ELF] Do not produce DT_JMPREL and DT_PLTGOT if .rela.plt is empty.
If .rela.plt is mentioned in a linker script, it might be preserved
even if it is empty. In that case, LLD created DT_JMPREL and DT_PLTGOT
dynamic tags. When the tags exist, a dynamic loader writes values into
reserved slots in .got.plt to support lazy symbol resolution.
The problem is that, in fact, the linker has not reserved that space,
and the writing may occur into the memory allocated for something else.

Differential Revision: https://reviews.llvm.org/D63869

llvm-svn: 364639
2019-06-28 10:14:14 +00:00
Fangrui Song 025a815d75 [ELF] Make the rule to create relative relocations in a writable section stricter
The current rule is loose: `!Sym.IsPreemptible || Expr == R_GOT`.

When the symbol is non-preemptable, this allows absolute relocation
types with smaller numbers of bits, e.g. R_X86_64_{8,16,32}. They are
disallowed by ld.bfd and gold, e.g.

    ld.bfd: a.o: relocation R_X86_64_8 against `.text' can not be used when making a shared object; recompile with -fPIC

This patch:

a) Add TargetInfo::SymbolicRel to represent relocation types that resolve to a
symbol value (e.g. R_AARCH_ABS64, R_386_32, R_X86_64_64).

  As a side benefit, we currently (ab)use GotRel (R_*_GLOB_DAT) to resolve
  GOT slots that are link-time constants. Since we now use Target->SymbolRel
  to do the job, we can remove R_*_GLOB_DAT from relocateOne() for all targets.
  R_*_GLOB_DAT cannot be used as static relocation types.
b) Change the condition to `!Sym.IsPreemptible && Type != Target->SymbolicRel || Expr == R_GOT`.

Some tests are caught by the improved error checking (ld.bfd/gold also
issue errors on them). Many misuse .long where .quad should be used
instead.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63121

llvm-svn: 363059
2019-06-11 12:59:30 +00:00
Peter Collingbourne 0282898586 ELF: Create synthetic sections for loadable partitions.
We create several types of synthetic sections for loadable partitions, including:
- The dynamic symbol table. This allows code outside of the loadable partitions
  to find entry points with dlsym.
- Creating a dynamic symbol table also requires the creation of several other
  synthetic sections for the partition, such as the dynamic table and hash table
  sections.
- The partition's ELF header is represented as a synthetic section in the
  combined output file, and will be used by llvm-objcopy to extract partitions.

Differential Revision: https://reviews.llvm.org/D62350

llvm-svn: 362819
2019-06-07 17:57:58 +00:00
Fangrui Song abb7484c31 [ELF] Don't create an output section named `/DISCARD/` if it is assigned to the special phdr `NONE`
Fixes the remaining issue of PR41673 after D61186: with `/DISCARD/ { ... } :NONE`,
we may create an output section named `/DISCARD/`.

Note, if an input section is named `/DISCARD/`, ld.bfd discards it but
lld keeps it. It is probably not worth copying this behavior as it is unrealistic.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62768

llvm-svn: 362356
2019-06-03 05:34:25 +00:00
Fangrui Song 750d148e8f [ELF][test] Restore linkerscript/symbol-location.s to test getLinkerScriptLocation()
The test (the only test that checks getLinkerScriptLocation()) deleted
by r358652 can be restored by replacing R_X86_64_PLT32 with
R_X86_64_PC32, and changing -pie to -shared (preemptable). Then, the
symbol will not be a link-time constant and a -fPIC error will be
issued.

llvm-svn: 362207
2019-05-31 08:20:43 +00:00
Fangrui Song ecf4c9e13c [ELF] Don't advance position in a memory region when assigning to the Dot
For memory5.test, ld.bfd appears to ignore `. += 0x2000;`, so the test was testing
a wrong behavior. After deleting the code added in rLLD336335, we match ld.bfd and thus fix PR41357.

PR37836 (memory4.test) seems to have been fixed by another change.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D62177

llvm-svn: 361228
2019-05-21 08:21:44 +00:00
Bob Haarman 5ff1eb6418 Revert r358069 "Discard debuginfo for object files empty after GC"
The change broke some scenarios where debug information is still
needed, although MarkLive cannot see it, including the
Chromium/Android build. Reverting to unbreak that build.

llvm-svn: 360955
2019-05-16 23:33:06 +00:00
Peter Smith 4e21c770ec [ELF] Full support for -n (--nmagic) and -N (--omagic) via common page
The -n (--nmagic) disables page alignment, and acts as a -Bstatic
The -N (--omagic) does what -n does but also marks the executable segment as
writeable. As page alignment is disabled headers are not allocated unless
explicit in the linker script.

To disable page alignment in LLD we choose to set the page sizes to 1 so
that any alignment based on the page size does nothing. To set the
Target->PageSize to 1 we implement -z common-page-size, which has the side
effect of allowing the user to set the value as well.

Setting the page alignments to 1 does mean that any use of
CONSTANT(MAXPAGESIZE) or CONSTANT(COMMONPAGESIZE) in a linker script will
return 1, unlike in ld.bfd. However given that -n and -N disable paging
these probably shouldn't be used in a linker script where -n or -N is in
use.

Differential Revision: https://reviews.llvm.org/D61688

llvm-svn: 360593
2019-05-13 16:01:26 +00:00
Fangrui Song c669ef1721 Delete trailing \r. NFC
llvm-svn: 359745
2019-05-02 00:39:03 +00:00
Ben Dunbobbin 6e32dd6cfd [LLD] Emit dynamic relocations for references to script symbols in -pie links
https://reviews.llvm.org/D55423 caused LLD to stop emitting dynamic relocations for references to script symbols in -pie links.

This patch fixes that regression.

https://reviews.llvm.org/D61298

llvm-svn: 359683
2019-05-01 14:07:31 +00:00
Fangrui Song 5387c2cd17 [llvm-objdump] Print newlines before and after "Disassembly of section ...:"
This improves readability and the behavior is consistent with GNU objdump.

The new test test/tools/llvm-objdump/X86/disassemble-section-name.s
checks we print newlines before and after "Disassembly of section ...:"

Differential Revision: https://reviews.llvm.org/D61127

llvm-svn: 359668
2019-05-01 10:40:48 +00:00
Fangrui Song 4672e52e22 [llvm-readobj] llvm-readobj --elf-output-style=GNU => llvm-readelf
While updating the test, change -l -S to -S -l as the output of -S goes
before -l.

llvm-svn: 359653
2019-05-01 06:02:16 +00:00
Fangrui Song b159906a9a [test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:

-s => -S
-t => --symbols
-sd => --section-data

llvm-svn: 359651
2019-05-01 05:49:01 +00:00
Andrew Ng 24896d304d [LLD][ELF] /DISCARD/ output sections should not be orphans
/DISCARD/ output sections were being treated as orphans. As a result, if
a /DISCARD/ output section has been assigned a PHDR, it could cause
incorrect assignment of sections to segments.

Differential Revision: https://reviews.llvm.org/D61186

llvm-svn: 359565
2019-04-30 14:31:22 +00:00
Andrew Ng 0f4c58f6f4 [LLD][ELF] Fix getRankProximity to "ignore" not live sections
This is a follow up to r358979 which made findOrphanPos only consider
live sections. Unfortunately, this required change to getRankProximity,
used by findOrphanPos, was missed.

Differential Revision: https://reviews.llvm.org/D61197

llvm-svn: 359554
2019-04-30 12:27:06 +00:00
George Rimar dee900ae59 [LLD][ELF] - Do not remove empty sections referenced in LOADADDR/ADDR commands.
This is https://bugs.llvm.org//show_bug.cgi?id=38750.

If script references empty sections in LOADADDR/ADDR commands

.empty  : { *(.empty ) }
.text   : AT(LOADADDR (.empty) + SIZEOF (.empty)) { *(.text) }
then an empty section will be removed and LOADADDR/ADDR will evaluate to null.
It is not that user may expect from using of the generic script, what is a common case.

Differential revision: https://reviews.llvm.org/D54621

llvm-svn: 359279
2019-04-26 06:59:30 +00:00
Andrew Ng ccba42c7eb [ELF] Change default output section type to SHT_PROGBITS
This fixes an issue where a symbol only section at the start of a
PT_LOAD segment, causes incorrect alignment of the file offset for the
start of the segment which results in the output of an invalid ELF.

SHT_PROGBITS was the default output section type in the past.

Differential Revision: https://reviews.llvm.org/D60131

llvm-svn: 358981
2019-04-23 12:38:52 +00:00
George Rimar f902250fc1 [LLD][ELF] - Handle quoted strings in the linker scripts correctly.
This is the https://bugs.llvm.org/show_bug.cgi?id=41356,

Seems it is kind of unusual case but it is possible to
have sections that require quotes for their namings.
Like "aaa bbb".

This patch adds support for those.

Differential revision: https://reviews.llvm.org/D60901

llvm-svn: 358874
2019-04-22 07:57:07 +00:00
George Rimar 5f7665969a [LLD][ELF] - Fix mistype. NFC.
Change the tripple name from
aarch64-linux-gnux to -triple=aarch64-linux-gnu

llvm-svn: 358810
2019-04-20 10:50:27 +00:00
George Rimar 55e1987f81 [LLD][ELF] - Convert out-of-order-section-in-region.s to *.test. NFCI.
This is consistent with the our others tests that has large scripts.

llvm-svn: 358659
2019-04-18 12:13:41 +00:00
George Rimar 69186f82f3 [LLD][ELF] - A fix for "linker script assignment loses relative nature of section" bug.
This is https://bugs.llvm.org//show_bug.cgi?id=39857.
I added the comment with much more details to the bug page,
the short version is below.

The following script and code demonstrates the issue:

aliasto__text = __text;
 SECTIONS {
  .text 0x1000 : { __text = . ; *(.text) }
 }
...
call aliasto__text

LLD fails with "cannot refer to absolute symbol: aliasto__text" error.
It happens because at the moment of scanning the relocations
we do not yet assign the correct/final/any section value for the symbol aliasto__text.
I made a change to Relocations.cpp to fix that.

Also, I had to remove the symbol-location.s test case completely, because now it does not
trigger any error. Since now all linker scripts symbols are resolved to constants, no
errors can be triggered at all it seems. I checked that it is consistent with the behavior
of bfd and gold (they do not trigger errors for the case from symbol-location.s), so it should
be OK. I.e. at least it is probably not the best possible, but natural behavior we obtained.

Differential revision: https://reviews.llvm.org/D55423

llvm-svn: 358652
2019-04-18 10:00:37 +00:00
Fangrui Song 3deff86657 [ELF] Respect NonAlloc when copying flags from the previous sections
Summary:
If the output section contains only symbol assignments, we copy flags
from the previous sections. Don't set SHF_ALLOC if NonAlloc is true.

We also have to change the type from SHT_NOBITS to SHT_PROGBITS.
In ld.bfd, bfd_elf_get_default_section_type maps non-alloctable sections to SHT_PROGBITS.
Non-alloctable SHT_NOBITS sections do not make sense.

Fixes PR38626

Differential Revision: https://reviews.llvm.org/D59986

llvm-svn: 358650
2019-04-18 09:22:05 +00:00
George Rimar da49faf15e [LLD][ELF] - Fix the different behavior of the linker script symbols on different platforms.
This generalizes code and also fixes the broken behavior shown in
one of our test cases for some targets, like x86-64.

The issue occurs when the forward declarations are used in the script.
One of the samples is:

SECTIONS {
  foo = ADDR(.text) - ABSOLUTE(ADDR(.text));
};

In that case, we have a broken output when output target does
not use thunks. That happens because thunks creating code
(called from maybeAddThunks)
calls Script->assignAddresses() at least one more time,
what fixups the values. As a result final symbols values can
be different on AArch64 and x86, for example.

In this patch, I generalize and rename maybeAddThunks to
finalizeAddressDependentContent and now it is used and called
by all targets.

Differential revision: https://reviews.llvm.org/D55550

llvm-svn: 358646
2019-04-18 08:15:54 +00:00
Rui Ueyama 14ef9b30b6 lld: elf: Fix sections with explict addresses in regions
Patch by Gabriel Smith.

The address for a section would be evaluated before the region was
switched to. Because of this, the position within the region would not
be updated. After the region is swapped to the dot would be set to the
out of date position within the region, undoing the section address
evaluation.

To fix this, the region is swapped to before the section's address is
evaluated. As part of the fallout of this, expandMemoryRegions needed
to be gated in setDot on the condition that the evaluated address is
less than the dot. This is for the case where sections are not listed
from lowest address to highest address.

Finally, a test for the case where sections are listed "out of order"
was added.

Differential Revision: https://reviews.llvm.org/D60744

llvm-svn: 358638
2019-04-18 02:32:12 +00:00
Fangrui Song abc068fc59 [ELF] Fix typo: .symtab_shndxr -> .symtab_shndx
The typo was introduced to llvm MC in rL204769 (fixed in rL358247) and then to lld.

Also, for relocatable-many-sections.s, the size of .symtab changed at some point and the formula needs update.

llvm-svn: 358248
2019-04-12 02:20:52 +00:00
Rui Ueyama 3a8bb7cd2c Discard debuginfo for object files empty after GC
Patch by Robert O'Callahan.

Rust projects tend to link in all object files from all dependent
libraries and rely on --gc-sections to strip unused code and data.
Unfortunately --gc-sections doesn't currently strip any debuginfo
associated with GC'ed sections, so lld links in the full debuginfo from
all dependencies even if almost all that code has been discarded. See
https://github.com/rust-lang/rust/issues/56068 for some details.

Properly stripping debuginfo for discarded sections would be difficult,
but a simple approach that helps significantly is to mark debuginfo
sections as live only if their associated object file has at least one
live code/data section. This patch does that. In a (contrived but not
totally artificial) Rust testcase linked above, it reduces the final
binary size from 46MB to 5.1MB.

Differential Revision: https://reviews.llvm.org/D54747

llvm-svn: 358069
2019-04-10 10:37:10 +00:00
Fangrui Song e8710ef1fb [ELF] Split RW PT_LOAD on the PT_GNU_RELRO boundary
Summary:
Based on Peter Collingbourne's suggestion in D56828.

Before D56828: PT_LOAD(.data PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .bss)
Old:           PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .data .bss)
New:           PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro)) PT_LOAD(.data. .bss)

The new layout reflects the runtime memory mappings.
By having two PT_LOAD segments, we can utilize the NOBITS part of the
first PT_LOAD and save bytes for .bss.rel.ro.

.bss.rel.ro is currently small and only used by copy relocations of
symbols in read-only segments, but it can be used for other purposes in
the future, e.g. if a relro section's statically relocated data is all
zeros, we can move it to .bss.rel.ro.

Reviewers: espindola, ruiu, pcc

Reviewed By: ruiu

Subscribers: nemanjai, jvesely, nhaehnle, javed.absar, kbarton, emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58892

llvm-svn: 356226
2019-03-15 01:29:57 +00:00
Fangrui Song 07f8daf05e [ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo
Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss)

The placement of | indicates page alignment caused by PT_GNU_RELRO. The
new layout has simpler rules and saves space for many cases.

Old size: roundup(.data) + roundup(.data.rel.ro)
New size: roundup(.data.rel.ro + .bss.rel.ro) + .data

Other advantages:

* At runtime the 3 memory mappings decrease to 2.
* start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This
  simplifies binary manipulation tools.
  GNU strip before 2.31 discards PT_GNU_RELRO if its
  address is not equal to the start of its associated PT_LOAD.
  This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f
  But with this change, we will be compatible with GNU strip before 2.31
* Before, .got.plt (non-relro by default) was placed before .got (relro
  by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_
  (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END)
  (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we
  can improve on this regard if we'd like to.

Reviewers: ruiu, espindola, pcc

Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert

Differential Revision: https://reviews.llvm.org/D56828

llvm-svn: 356117
2019-03-14 03:47:45 +00:00
Peter Collingbourne 16d9a0acfd ELF: Change FileSize back to a uint64_t.
This lets us detect file size overflows when creating a 64-bit binary on
a 32-bit machine.

Differential Revision: https://reviews.llvm.org/D58840

llvm-svn: 355218
2019-03-01 18:53:41 +00:00
Peter Collingbourne 7fb9eabda5 ELF: Write .eh_frame_hdr explicitly after writing .eh_frame.
This lets us remove the special case from Writer::writeSections(), and also
fixes a bug where .eh_frame_hdr isn't necessarily written in the correct
order if a linker script moves .eh_frame and .eh_frame_hdr into the same
output section.

Differential Revision: https://reviews.llvm.org/D58795

llvm-svn: 355153
2019-02-28 23:11:35 +00:00
Rui Ueyama 016833bac2 lld: unquote possibly quoted `EXTERN("symbol")` entry in linker script.
gold accepts quoted strings. binutils requires quoted strings for some
kinds of symbols, e.g.:

  it accepts quoted symbols with @ in name:

  $ echo 'EXTERN("__libc_start_main@@GLIBC_2.2.5")' > a.script
  $ g++ a.script
  /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o: In function `_start':
  (.text+0x20): undefined reference to `main'
  collect2: error: ld returned 1 exit status

  but rejects them if unquoted:

  $ echo 'EXTERN(__libc_start_main@@GLIBC_2.2.5)' > a.script
  $ g++ a.script
  a.script: file not recognized: File format not recognized
  collect2: error: ld returned 1 exit status

To maintain compatibility with existing linker scripts support quoted
strings in lld as well.

Patch by Lucian Adrian Grijincu.

Differential Revision: https://reviews.llvm.org/D57987

llvm-svn: 353756
2019-02-11 22:01:32 +00:00
Matt Davis 0d0e9c08a4 [llvm-readobj] Display sections that do not belong to a segment in the section-mapping
Summary:
The following patch adds the "None" line to the section to segment mapping dump.
That line lists the sections that do not belong to any segment.
I realize that this change differs from GNU readelf which does not display the latter information.

I'd rather not add this "feature" under a command line option.  I think that might introduce confusion, since users would have to
make an additional decision as to if they want to see all of the section-to-segment map or just a subset of it.

Another option is to only print the "None" line if the `--section-mapping` option is passed; however,
that might also introduce some confusion, because the section-to-segment map would be different between`--program-headers`
and the `--section-mapping` output.  While the difference is just the "None" line, it seems that if we choose to display
the segment-to-section mapping, then we should always display the whole map including the sections
that do not belong to segments.

```
Section to Segment mapping:
  Segment Sections...
   00
   01     .interp
   02     .interp .note.ABI-tag .gnu.hash
   03     .init_array .fini_array .dynamic
   04     .dynamic
   05     .note.ABI-tag
   06     .eh_frame_hdr
   07
   08     .init_array .fini_array .dynamic .got
   None   .comment .symtab .strtab .shstrtab <--- THIS LINE
```

Reviewers: grimar, rupprecht, jhenderson, espindola

Reviewed By: rupprecht

Subscribers: khemant, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D57700

llvm-svn: 353217
2019-02-05 21:01:01 +00:00
George Rimar 8bb8433a1a [LLD][ELF] - Update tests after r352366.
r352366 "[llvm-objdump] - Print LMAs when dumping section headers." changed the format of
llvm-objdump output. We have to update the LLD tests.

llvm-svn: 352372
2019-01-28 15:03:47 +00:00
James Henderson b88d6fd7b8 [LLD][ELF]Fix tests for D56910
r351789 changes the output of llvm-readelf --dyn-symbols. This causes 3
LLD tests to break. This patch fixes them.

Reviewed by: ruiu

Differential Revision: https://reviews.llvm.org/D56911

llvm-svn: 351790
2019-01-22 09:35:47 +00:00
George Rimar 6552b29867 [LLD][ELF] - Fix tests after r350840.
D56076 (r350840) changed the llvm-objdump output.

This is a follow up commit to fix LLD test cases.

llvm-svn: 350842
2019-01-10 16:26:05 +00:00
James Henderson 4ba1777a2d [ELF] Remove checking for spurious '@' at the end of dynamic sym names
llvm-readobj currently has a bug (see PR40097) where it prints '@' at
the end of unversioned dynamic symbols. This bug will be fixed in a
separate later commit, but these tests need fixing first.

Reviewed by: ruiu, Higuoxing

Differential Revision: https://reviews.llvm.org/D56388

llvm-svn: 350614
2019-01-08 10:50:59 +00:00
George Rimar 751e6e1cf5 [LLD][ELF] - Report a location for symbols from the linker script when reporting an error.
When we report an error for symbols defined in the linker script,
we do not report the location properly.

For example:

ld.lld: error: relocation R_AARCH64_CALL26 cannot refer to absolute symbol: aliasto__text
>>> defined in <internal>
>>> referenced by rtoabs.o:(.text+0x4)

This patch fixes that.

Differential revision: https://reviews.llvm.org/D55360

llvm-svn: 349612
2018-12-19 10:19:40 +00:00
George Rimar 1f958ed269 [LLD][ELF] - Support discarding the .dynamic section.
This is a part of https://bugs.llvm.org/show_bug.cgi?id=39810.

Seems it turns out that supporting /DISCARD/ for the .dynamic section with the
linker script is something we can do easily. The patch does this.

Differential revision: https://reviews.llvm.org/D55211

llvm-svn: 348749
2018-12-10 09:24:49 +00:00
George Rimar ad667661c4 [ELF] - Allow discarding .dynsym from the linker script.
This is a part of https://bugs.llvm.org/show_bug.cgi?id=39810.
The patch allows discarding the .dynsym section using linker script.

Differential revision: https://reviews.llvm.org/D55218

llvm-svn: 348748
2018-12-10 09:13:36 +00:00
George Rimar 4af28e46ca [LLD][ELF] - Support discarding .dynstr section.
This is a part of https://bugs.llvm.org/show_bug.cgi?id=39810.
The patch allows discarding the .dynstr section using linker script.

Differential revision: https://reviews.llvm.org/D55215

llvm-svn: 348746
2018-12-10 09:07:30 +00:00
George Rimar b3be390f94 [ELF] - (-Map file) Implement printing of LMA for assignments outside of section declarations.
This was a missing piece.
We started to print LMAs and information about assignments,
but did not do that for assignments outside of section declarations yet.
The patch implements it.

Differential revision: https://reviews.llvm.org/D45314

llvm-svn: 348468
2018-12-06 09:04:52 +00:00
George Rimar f49fe218c2 [LLD][ELF] - Linker script: accept using a file name without a list of sections.
This is a part of
https://bugs.llvm.org/show_bug.cgi?id=39885

Linker script specification says:
"You can specify a file name to include sections from a particular file. You would
do this if one or more of your files contain special data that needs to be at a
particular location in memory."

LLD did not accept this syntax. The patch implements it.

Differential revision: https://reviews.llvm.org/D55324

llvm-svn: 348463
2018-12-06 08:34:52 +00:00
Rui Ueyama a592aeb35a ELF: allow non allocated sections to go into allocated sections
Patch from Andrew Kelley.

For context, see https://bugs.llvm.org/show_bug.cgi?id=39862

The use case is embedded / OS programming where the kernel wants
access to its own debug info via mapped dwarf info. I have a proof of
concept of this working, using this linker script snippet:

  .rodata : ALIGN(4K) {
    *(.rodata)
    __debug_info_start = .;
    KEEP(*(.debug_info))
    __debug_info_end = .;
    __debug_abbrev_start = .;
    KEEP(*(.debug_abbrev))
    __debug_abbrev_end = .;
    __debug_str_start = .;
    KEEP(*(.debug_str))
    __debug_str_end = .;
    __debug_line_start = .;
    KEEP(*(.debug_line))
    __debug_line_end =
    .;
    __debug_ranges_start
    = .;
    KEEP(*(.debug_ranges))
    __debug_ranges_end
    = .;
  }

Differential revision: https://reviews.llvm.org/D55276

llvm-svn: 348291
2018-12-04 18:47:44 +00:00
Martell Malone 15b6c453b8 [ELF] Allow discarding of .rela.plt
When linking the linux kernel on ppc64le

ld.lld -EL -m elf64lppc -Bstatic --orphan-handling=warn --build-id -o
.tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds --whole-archive
built-in.a --no-whole-archive --start-group lib/lib.a --end-group
ld.lld: error: discarding .rela.plt section is not allowed

The linker script discards with the following matches
*(.glink .iplt .plt .rela* .comment)

Differential Revision: https://reviews.llvm.org/D54871

llvm-svn: 348258
2018-12-04 12:37:56 +00:00
Rui Ueyama 3b6cd2c602 Show a proper error message if output file is too large.
At least on Linux, if a file size given to FileOutputBuffer is greater
than 2^63, it fails with "Invalid argument" error, which is not a
user-friendly error message. With this patch, lld prints out "output
file too large" instead.

llvm-svn: 348153
2018-12-03 17:42:57 +00:00
Jordan Rupprecht 5bd334aef7 [lld][NFC] Update tests to use -S instead of -s when using llvm-readelf.
Summary: llvm-readobj/readelf accepts both -s and -S as aliases for --sections. However with GNU readelf only -S means --section, and -s means --symbols. I would like to make llvm-readelf more compatible.

Reviewers: MaskRay, espindola

Reviewed By: MaskRay

Subscribers: emaste, arichardson, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D54118

llvm-svn: 346164
2018-11-05 20:39:06 +00:00
George Rimar 3608decaa5 [ELF] - Do not crash when -r output uses linker script with `/DISCARD/`
This is https://bugs.llvm.org/show_bug.cgi?id=39493.

We crashed previously because did not handle /DISCARD/ properly
when -r was used. I think it is uncommon to use scripts with -r, though I see
nothing wrong to handle the /DISCARD/ so that we will not crash at least.

Differential revision: https://reviews.llvm.org/D53864

llvm-svn: 345819
2018-11-01 09:20:06 +00:00
Rui Ueyama ea8cd00a1d Add OUTPUT_FORMAT linker script directive support.
This patch adds a support for OUTPUT_FORMAT linker script directive.
Since I'm not 100% confident with BFD names you can use in the directive
for all architectures, I added only a few in this patch. We can add
other names for other archtiectures later.

We still do not support triple-style OUTPUT_FORMAT directive, namely,
OUTPUT_FORMAT(bfdname, big, little). If you pass -EL (little endian)
or -EB (big endian) to the linker, GNU linkers pick up big or little
as a BFD name, correspondingly, so that you can use a single linker
script for bi-endian processor. I'm not sure if we really need to
support that, so I'll leave it alone for now.

Note that -m takes precedence over OUTPUT_FORAMT, but we always parse
a BFD name given to OUTPUT_FORMAT for error checking. You cannot write
an invalid name in the OUTPUT_FORMAT directive.

Differential Revision: https://reviews.llvm.org/D53495

llvm-svn: 344952
2018-10-22 20:50:01 +00:00
Rui Ueyama ae8c3176b8 Fix typo in a test file name.
llvm-svn: 344899
2018-10-22 13:15:19 +00:00
Rui Ueyama 2e9d40d5f4 [lld] Add more complete support for the INCLUDE command.
Patch by Ian Tessier.

This change adds INCLUDE support to the MEMORY and SECTION commands, and
to output sections, as per:

https://sourceware.org/binutils/docs/ld/File-Commands.html#File-Commands

Differential Revision: https://reviews.llvm.org/D52951

llvm-svn: 344368
2018-10-12 17:07:32 +00:00
Peter Collingbourne 6556e6b929 ELF: Don't examine values of linker script symbols during ICF.
These symbols are declared early with the same value, so they otherwise
appear identical to ICF.

Differential Revision: https://reviews.llvm.org/D51376

llvm-svn: 340998
2018-08-29 23:43:38 +00:00
George Rimar a46d08ebe6 [LLD][ELD] - Do not reject INFO output section type when used with a start address.
This is https://bugs.llvm.org/show_bug.cgi?id=38625

LLD accept this: 

".stack (INFO) : {", 

but not this:

".stack address_expression (INFO) :"

The patch fixes it.

Differential revision: https://reviews.llvm.org/D51027

llvm-svn: 340804
2018-08-28 08:39:21 +00:00
George Rimar dffc1911e2 [LLD][ELF] - Add a test for elf::getPriority(StringRef S)
It covers the following line with a test:
https://github.com/llvm-mirror/lld/blob/master/ELF/OutputSections.cpp#L383

llvm-svn: 339348
2018-08-09 15:05:25 +00:00
George Rimar cc8f8194ba [LLD][ELF] - Add a test for ScriptParser::readPhdrType().
This adds a test for https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L1289.

llvm-svn: 339342
2018-08-09 13:19:10 +00:00
George Rimar 5570d7d45b [LLD][ELF] - Add a test for ScriptParser::readOutputSectionDescription.
This covers the following line:
https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L415

llvm-svn: 339333
2018-08-09 12:14:00 +00:00
George Rimar b89367ac46 [LLD][ELF] - Add a test for ScriptParser::readPhdrs(). NFCI.
This covers the following line with a test:
https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L415

llvm-svn: 339327
2018-08-09 11:13:30 +00:00
Rui Ueyama e262bb1afb Add TARGET(foo) linker script directive.
GNU ld's manual says that TARGET(foo) is basically an alias for
`--format foo` where foo is a BFD target name such as elf64-x86-64.

Unlike GNU linkers, lld doesn't allow arbitrary BFD target name for
--format. We accept only "default", "elf" or "binary". This makes
situation a bit tricky because we can't simply make TARGET an alias for
--target.

A quick code search revealed that the usage number of TARGET is very
small, and the only meaningful usage is to switch to the binary mode.
Thus, in this patch, we handle only TARGET(elf.*) and TARGET(binary).

Differential Revision: https://reviews.llvm.org/D48153

llvm-svn: 339060
2018-08-06 21:29:41 +00:00
George Rimar 434341be5b [LLD][ELF] - Fix bug when reporting memory intersections.
rangeToString() takes addres and length,
previously it was called incorrectly.

llvm-svn: 338956
2018-08-04 10:34:52 +00:00
Chris Jackson 1a721eb3a2 [lld] Make tests calling llvm-ar more robust
Some lit tests that call llvm-ar use the 'r' flag. If the target archive
already exists and is in a corrupt state, this can cause the test to fail. We
have added 'rm -f' calls before the llvm-ar calls to increase the
robustness of the tests.

Differential revision: https://reviews.llvm.org/D49184

llvm-svn: 338705
2018-08-02 11:33:54 +00:00
George Rimar acf8cef80f [LLD] Do not overwrite LMAOffset of PT_LOAD header
Patch by Konstantin Schwarz!

If more than a single output section is added to a PT_LOAD header,
only the first section should set the LMAOffset of the segment.
Otherwise, we get a load-address overlap error

Differential revision: https://reviews.llvm.org/D50133

llvm-svn: 338697
2018-08-02 10:45:46 +00:00
George Rimar add69e9c19 [LLD] Only increase LMARegion if different from MemRegion
Patch by Konstantin Schwarz!

If both the MemRegion and LMARegion are set for an output section in
a linker script, we should only increase the LMARegion if it is
different from the MemRegion. Otherwise, we reserve the memory twice.

Differential revision: https://reviews.llvm.org/D50065

llvm-svn: 338684
2018-08-02 08:13:56 +00:00
George Rimar 34bdf27eaa [LLD] - Improve handling of AT> linker script commands
Patch by Konstantin Schwarz!

The condition to create a new phdr must also check the usage of "AT>" 
linker script command, and create a new PT_LOAD header if a new LMARegion is used.

This fixes PR38307

Differential revision: https://reviews.llvm.org/D50052

llvm-svn: 338679
2018-08-02 08:07:07 +00:00
George Rimar 9524dee72e [ELF] - Implement SHT_SYMTAB_SHNDX (.symtab_shndxr) section.
This is relative to https://bugs.llvm.org//show_bug.cgi?id=38119.

SHT_SYMTAB section is able to keep symbols with output section indices
up to 0xff00 (SHN_LORESERVE). But if we have indices that are greater
than that (PR shows that it might happen), we need to use
SHT_SYMTAB_SHNDX extended section. It was not supported by LLD.

Description of the SHT_SYMTAB_SHNDX section is here:
https://docs.oracle.com/cd/E19683-01/817-3677/chapter6-94076/index.html.

Differential revision: https://reviews.llvm.org/D49541

llvm-svn: 338247
2018-07-30 12:39:54 +00:00
Fangrui Song 31cc084619 [ELF] Fix linker-script-in-search-path.s
llvm-svn: 337983
2018-07-25 23:29:15 +00:00
Fangrui Song 7610b4d64c [ELF] Make linker-script-in-search-path.s robust per r337972
llvm-svn: 337975
2018-07-25 22:11:00 +00:00
George Rimar 061af9aafa [ELF] - Add test case for checking PT_INTERP behavior.
When PT_INTERP is specified in PHDRS command, it should be created.
(if other conditions met)

We had no test for the folowing line:
https://github.com/llvm-mirror/lld/blob/master/ELF/LinkerScript.cpp#L1108
And for this header itself.

Patch fixes that.

llvm-svn: 336359
2018-07-05 15:01:44 +00:00
George Rimar 9b99abcf99 [ELF] - Advance position in a memory region when change the Dot.
This is https://bugs.llvm.org//show_bug.cgi?id=37836

Previously LLD could assign to Dot or set the address
for the section with address expression but did not advance
the position in a memory region.

Patch fixes the issue.

llvm-svn: 336335
2018-07-05 10:44:17 +00:00
George Rimar a50054829d [ELF] - Add support for '||' and '&&' in linker scripts.
This is https://bugs.llvm.org//show_bug.cgi?id=37976,
we had no support, but seems someone faced it.

llvm-svn: 336197
2018-07-03 14:02:52 +00:00
James Henderson b427d4eced [ELF] Don't create empty output section for unreferenced PROVIDEs
LLD removes empty output sections otherwise specified in the linker
script. Prior to this change however, if section descriptions included
ANY kind of symbol assignment, then the consequent output section would
not be removed, even if the assignment was marked with PROVIDE and not
actually triggered (i.e. the symbol was never referenced). This change
modifies the isDiscarable function to ignore such directives when
determining whether a section should be discarded, in keeping with
bfd's behaviour. Symbol assignments that do result in a symbol
definition will continue to result in a kept section (this is not
actually the same as bfd's behaviour, but it is simpler, and probably
makes more sense).

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D48771

llvm-svn: 336184
2018-07-03 09:23:25 +00:00
George Rimar 34d2333c07 [ELF] - Revert huge-temporary-file.s changed in r336129
Comment in the test case says that:

## This inputs previously created a 4gb temporarily file under 32 bit
## configuration. Issue was fixed. There is no clean way to check that from here.
## This testcase added for documentation purposes.

The intention of the test was to create such huge file
in case if our code will be broken again.
And currently it documents we do not create huge outputs.

r336129 changed -o to /dev/null and broke the intentions of the test case.

llvm-svn: 336179
2018-07-03 08:30:55 +00:00
Fangrui Song 841ae5ab1e [ELF] Fix other tests after r336129
llvm-svn: 336136
2018-07-02 19:17:03 +00:00
Fangrui Song 40a9f2251b [ELF] Replace unused output filenames with /dev/null in tests
Post commit review at rLLD335992

llvm-svn: 336129
2018-07-02 17:48:23 +00:00
George Rimar 0751a0307a [ELF] - Linker script: add tests for checking malformed numbers parsing.
Previoulsy we had no test that covered malfolmed numbers
with 'H', 'K' and 'M' suffixes, so the following lines
were uncovered:

https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L996
https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L1003
https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L1008

Patch fixes that.

llvm-svn: 335979
2018-06-29 14:29:44 +00:00
George Rimar a582419ac7 [ELF] - Implement linker script OVERLAYs.
This is PR36768.

Linker script OVERLAYs are described in 4.6.9. Overlay Description of the spec:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/sections.html

They are used to allow output sections which have different LMAs but the same VAs
and used for embedded programming.

Currently, LLD restricts overlapping of sections and that seems to be the most desired
behaviour for defaults. My thoughts about possible approaches for PR36768 are on the bug page,
this patch implements OVERLAY keyword and allows VAs overlapping for sections that within the overlay.

Differential revision: https://reviews.llvm.org/D44780

llvm-svn: 335714
2018-06-27 08:08:12 +00:00
Fangrui Song 3d87323a7e [ELF] Make non-writable non-executable PROGBITS sections closer to .text
This generalizes the old heuristic placing SHT_DYNSYM SHT_DYNSTR first in the readonly SHF_ALLOC segment.

Reviewers: espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48406

llvm-svn: 335674
2018-06-26 22:13:32 +00:00
Fangrui Song 68fa4e8c34 [ELF] Assign RF_EXEC rank even if --no-rosegment or SECTIONS command is used
Summary:
Currently when --no-rosegment is specified or a linker script with SECTIONS command is used,
.rodata (A) .text (AX) are assigned the same rank and .rodata may be placed after .text .
This increases the gap between .text and .bss and can cause pc-relative relocation overflow (e.g. gcc crtbegin.o crtbegin.S have R_X86_64_PC32 relocation from .text to .bss).

This patch makes SingleRoRx affect only segment layout, not section layout. As a consequence, .rodata will be placed before .text regardless of SingleRoRx.

Reviewers: espindola, ruiu, grimar, echristo, javed.absar

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48405

llvm-svn: 335627
2018-06-26 17:04:47 +00:00
Fangrui Song 74282efee1 [ELF] Fix sort-non-script.s
llvm-svn: 335499
2018-06-25 17:16:01 +00:00
Fangrui Song 5ea154402e [ELF] Change test files for style consistency. NFC
* Move `REQUIRES:` line to the top
* llvm-mc ... -o %t -> llvm-mc ... -o %t.o
* Don't check "TEXT" "DATA" columns (they are bfd-style names that do
not fit into llvm well) in llvm-objdump output

llvm-svn: 335498
2018-06-25 17:07:40 +00:00
Fangrui Song 65c50074c2 [ELF] readobj -elf-output-style=GNU -> readelf
Style change for consistency. NFC

llvm-svn: 335494
2018-06-25 16:49:52 +00:00
Fangrui Song e737e75491 [ELF] Change llvm-objdump output for D48472: TEXT DATA -> TEXT
Reviewers: jyknight, Bigcheese, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D48473

llvm-svn: 335404
2018-06-23 00:15:23 +00:00
Joel Jones a5752e199c [lld] Add REQUIRES: x86 where needed to tests
If building lld without x86 support, tests that require that support should
be treated as unsupported, not errors.

Tested using:
  1. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64;X86'
     make check-lld
     =>
     Expected Passes    : 1406
     Unsupported Tests  : 287

  2. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64'
     make check-lld
     =>
     Expected Passes    : 410
     Unsupported Tests  : 1283

Patch by Joel Jones

Differential Revision: https://reviews.llvm.org/D47748

llvm-svn: 334095
2018-06-06 13:56:51 +00:00
Rui Ueyama b75d19c36c Make ALIGN work with -r in linker scripts
Patch by Mark Kettenis.

Make ALIGN work in linker scripts used with the -r option. This works in
GNU ld (ld.bfd) and is used to generate the "random gap" object for
linking the OpenBSD kernel.

Differential Revision: https://reviews.llvm.org/D46839

llvm-svn: 332656
2018-05-17 20:22:39 +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
Fangrui Song 95851515d7 Add a CIE with length 0 unconditionally.
Summary: This is not technically required, but glibc unwind-dw2-fde.c classify_object_over_fdes expects there is a CIE record length 0 as a terminator.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D46566

llvm-svn: 331708
2018-05-08 01:19:16 +00:00
George Rimar d30a78b3fe [ELF] - Eliminate the AssertCommand.
Currently, LLD supports ASSERT as a separate command.

We support two forms now.

Assign expression-form: . = ASSERT(0x100)
(old GNU ld required it and some scripts in the wild are still using
something like . = ASSERT((_end - _text <= (512 * 1024 * 1024)), "kernel image bigger than KERNEL_IMAGE_SIZE");

Nowadays above is not a mandatory form and command-like form is commonly used:
ASSERT(<expr>, "text);

The return value of the ASSERT is Dot. That was implemented in D30171.
It looks like (2) is just a short version of (1) then.

GNU ld does *not* list ASSERT as a SECTIONS command:
https://sourceware.org/binutils/docs/ld/SECTIONS.html#SECTIONS

Given above we probably can change ASSERT to be an assignment to Dot. 
That makes the rest of the code much simpler. Patch do that.

Differential revision: https://reviews.llvm.org/D45434

llvm-svn: 330814
2018-04-25 11:16:31 +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 aeb7e305b8 [ELF] - Simplify test case. NFC.
llvm-svn: 329563
2018-04-09 13:13:36 +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
Rui Ueyama 4e150c4c88 Make "Size" column in the map file one characters shorter.
Previously, "size" column is 9 characters long which is too long
at least for 32-bit (because at maximum it needs 8 columns). This
patch make it one column shorter than before. That's also a reasonable
default for 64-bit.

llvm-svn: 329317
2018-04-05 17:20:18 +00:00
Rui Ueyama 16a130bc78 Fix column size in the map file.
Size can be narrow, but LMA should be the same width as VMA.

llvm-svn: 329312
2018-04-05 16:45:37 +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 e88b76a989 [ELF] - Reveal more information in -Map file about assignments.
Currently, LLD print symbol assignment commands to the map file,
but it does not do that for assignments that are outside of the section
descriptions. Such assignments can affect the layout though.

The patch implements the following:

* Teaches LLD to print symbol assignments outside of section declaration.
* Teaches LLD to print PROVIDE/HIDDEN/PROVIDE hidden commands.

In case when symbol is not provided, nothing will be printed.

Differential revision: https://reviews.llvm.org/D44894

llvm-svn: 329272
2018-04-05 11:25:58 +00:00
George Rimar ee01b1d390 [ELF] - Print LMA in a -Map file.
Currently, LLD prints VA, but not LMA in a map file.
It seems can be useful to print both to reveal layout
details and patch implements it.

Differential revision: https://reviews.llvm.org/D44899

llvm-svn: 329271
2018-04-05 10:51:06 +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 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
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
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
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
George Rimar 76f1c78dea [ELF] - Simplify test case. NFCI.
llvm-svn: 327614
2018-03-15 09:26:08 +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
George Rimar 271ed6eb0d [ELF] - Convert overlapping-sections.s testcase to x86 and cleanup.
Patch do the following changes:

* Test case was converted from MIPS to x86.

* Removed part of the test checking we are able to produce a valid output.
  Since we do that already in other tests, this one's intention should be
  only to check we are still able to report overlaps and/or produce
  broken output with overlaps.

Differential revision: https://reviews.llvm.org/D44438

llvm-svn: 327480
2018-03-14 07:44:23 +00:00
George Rimar b9f4b70f20 [ELF} - Fix build bots.
llvm-svn: 327419
2018-03-13 16:23:48 +00:00
George Rimar b7288836ca [ELF] - Fix mistype in comment. NFC.
llvm-svn: 327417
2018-03-13 16:11:02 +00:00
George Rimar f95e7c6f7a [ELF] - Rename test cases to *.test.
This is a follow-up for r327410.

llvm-svn: 327416
2018-03-13 16:02:45 +00:00
George Rimar cfd2c97008 [ELF] - Represent tests as linker scripts instead of asm.
This follows recently started direction and sometimes
allows to fully get rid from `echo` calls.

I'll rename changed files to *.test in a follow-up.

llvm-svn: 327410
2018-03-13 15:47:14 +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 ebc1d1fdde [ELF] - Fix wrong "REQUIRES" in test.
Its a follow up for r327374 to fix BB.

llvm-svn: 327377
2018-03-13 08:50:36 +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 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
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
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