227 Commits

Author SHA1 Message Date
Fangrui Song
8d85c96e0e [lld] StringRef::{starts,ends}with => {starts,ends}_with. NFC
The latter form is now preferred to be similar to C++20 starts_with.
This replacement also removes one function call when startswith is not inlined.
2023-06-05 14:36:19 -07:00
Kazu Hirata
ed1539c6ad Migrate {starts,ends}with_insensitive to {starts,ends}_with_insensitive (NFC)
This patch migrates uses of StringRef::{starts,ends}with_insensitive
to StringRef::{starts,ends}_with_insensitive so that we can use names
similar to those used in std::string_view.

Note that the llvm/ directory has migrated in commit
6c3ea866e93003e16fc55d3b5cedd3bc371d1fde.

I'll post a separate patch to deprecate
StringRef::{starts,ends}with_insensitive.

Differential Revision: https://reviews.llvm.org/D150506
2023-05-16 10:12:42 -07:00
Peter Smith
e16af8a281 [LLD][ELF] Add missing program header parsing to OVERLAY
In D72756 the change to add INPUT_SECTION_FLAGS inadvertantly
removed the line to parse the program header assignment information for
OutputSections within an OVERLAY.

This change adds back the missing line and adds a test for it.

Differential Revision: https://reviews.llvm.org/D150445
2023-05-15 10:04:33 +01:00
Simi Pallipurath
2f68ddc604 [lld][ARM][2/3]Big Endian support - Word invariant support
Changes:
 - Adding BE32 big endian Support for Arm.
 - Replace the writele and readle with their endian-aware versions.
 - Adding test cases for the big-endian be32 arm configuration.

     Patch by: Milosz Plichta. This patch merges all the changes from
     this patch https://reviews.llvm.org/D140203 as well.

Reviewed By: peter.smith, MaskRay

Differential Revision: https://reviews.llvm.org/D140202
2023-03-29 10:21:00 +01:00
Justin Cady
447aa48b4a [ELF] Add REVERSE input section description keyword
The `REVERSE` keyword is described here:

https://sourceware.org/bugzilla/show_bug.cgi?id=27565

It complements `SORT` by allowing the order of input sections to be reversed.

This is particularly useful for order-dependent sections such as .init_array,
where `REVERSE` can be used to either detect static initialization order fiasco
issues or as a mechanism to maintain .ctors element order while transitioning to
the modern .init_array. Such a transition is described here:

https://discourse.llvm.org/t/is-it-possible-to-manually-specify-init-array-order/68649

Differential Revision: https://reviews.llvm.org/D145381
2023-03-07 12:44:02 -05:00
Fangrui Song
d60ef9338d [ELF] Support quoted output section names
Similar to e7a7ad134fe182aad190cb3ebc441164470e92f5 and
2bf06d9345caeb26520be8e830c092683bbdf0f7 for other linker script syntax.

Close https://github.com/llvm/llvm-project/issues/60496
2023-02-03 11:03:00 -08:00
Kazu Hirata
c68af42fa8 [lld] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-02 23:12:36 -08:00
Jan Svoboda
abf0c6c0c0 Use CTAD on llvm::SaveAndRestore
Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D139229
2022-12-02 15:36:12 -08:00
Guillaume Chatelet
08e2a76381 [lld][NFC] rename ELF alignment into addralign 2022-12-01 16:20:12 +00:00
Fangrui Song
4191fda69c [ELF] Change most llvm::Optional to std::optional
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-11-26 19:19:15 -08:00
Fangrui Song
f596d82385 [ELF] Move driver into ctx and remove indirection. NFC
This removes one global variable and removes GOT and unique_ptr indirection.
2022-10-01 15:12:50 -07:00
Fangrui Song
9c626d4a0d [ELF] Remove symtab indirection. NFC
Add LLVM_LIBRARY_VISIBILITY to remove unneeded GOT and unique_ptr indirection.
2022-10-01 14:46:49 -07:00
Fangrui Song
85cfd91723 [ELF] Optimize some non-constant alignTo with alignToPowerOf2. NFC
My x86-64 lld executable is 2KiB smaller. .eh_frame writing gets faster as there
were lots of divisions.
2022-07-24 11:20:49 -07:00
Fangrui Song
b95cca03cd [ELF] Improve compound assignment tests
Also use strchr instead of is_contained.
2022-06-25 22:30:52 -07:00
Fangrui Song
0a0effdd5b [ELF] Support -= *= /= <<= >>= &= |= in symbol assignments 2022-06-25 22:22:59 -07:00
Fangrui Song
21bf6bb3d3 [ELF] Fix assertion failure when PROVIDE/HIDDEN/PROVIDE_HIDDEN does not have = 2022-06-25 20:26:47 -07:00
Fangrui Song
fe0de25b21 [ELF] Allow an expression to follow = in a symbol assignment
GNU ld doesn't require whitespace before =. Match it.
2022-06-25 20:25:34 -07:00
Fangrui Song
b0d6dd3905 [ELF] Fix precedence of ? when there are 2 or more operators on the left hand side
For 1 != 1 <= 1 ? 1 : 2, the current code incorrectly considers that ?
has a higher precedence than != (minPrec).

Also, add a test for right associativity.
2022-06-25 13:48:52 -07:00
Fangrui Song
d479b2e4db [ELF] Fix precedence of == and != in expressions
In GNU ld, the == and != operators have lower precedence than < > <= >=.
This behavior matches C.
2022-06-25 13:47:32 -07:00
Fangrui Song
4cb05dc3cb [ELF] Support quoted name in the TARGET command 2022-06-25 12:31:20 -07:00
Fangrui Song
363b29567e [ELF] Support quoted symbol in the ENTRY command
This matches GNU ld and matches other places we unquote the symbol name.

Fixes #56208
2022-06-25 12:19:45 -07:00
Ben Shi
8527f32f0a [lld][ELF] Support BFD name elf32-avr
Reviewed By: MaskRay

differential Revision: https://reviews.llvm.org/D125544
2022-05-18 00:00:14 +00:00
Fangrui Song
177fd72f5f [ELF] Disallow input section description without a filename
GNU ld does not allow `.foo : { (*foo) }`, but we may recognize it as three
input section descriptions: file "(" with any section name, file "*foo" with
any section name, file ")" with any section name. Disallow the error-prone usage.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D125523
2022-05-13 11:06:01 -07:00
Fangrui Song
5a44980f0a [ELF] Support custom sections between DATA_SEGMENT_ALIGN and DATA_SEGMENT_RELRO_END
We currently hard code RELRO sections. When a custom section is between
DATA_SEGMENT_ALIGN and DATA_SEGMENT_RELRO_END, we may report a spurious
`error: section: ... is not contiguous with other relro sections`. GNU ld
makes such sections RELRO.

glibc recently switched to default --with-default-link=no. This configuration
places `__libc_atexit` and others between DATA_SEGMENT_ALIGN and
DATA_SEGMENT_RELRO_END. This patch allows such a ld.bfd --verbose
linker script to be fed into lld.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D124656
2022-05-04 01:10:46 -07:00
Fangrui Song
6c814931bc [ELF] Don't use multiple inheritance for OutputSection. NFC
Add an OutputDesc class inheriting from SectionCommand. An OutputDesc wraps an
OutputSection. This change allows InputSection::getParent to be inlined.

Differential Revision: https://reviews.llvm.org/D120650
2022-03-08 11:23:42 -08:00
Fangrui Song
9e9c86fd67 [ELF] Change some non-null pointer parameters to references. NFC
To decrease difference for D120650. Also, rename some `OutputSection *sec` (and
`cmd`) to the more common `osec`.
2022-02-28 11:19:00 -08:00
Fangrui Song
b01430a04f [ELF] Don't rely on Symbols.h's transitive inclusion of InputFiles.h. NFC 2022-02-23 19:18:24 -08:00
Fangrui Song
66f8ac8d36 [ELF] Support (TYPE=<value>) to customize the output section type
The current output section type allows to set the ELF section type to
SHT_PROGBITS or SHT_NOLOAD. This patch allows an arbitrary section value
to be specified. Some common SHT_* literal names are supported as well.

```
SECTIONS {
  note (TYPE=SHT_NOTE) : { BYTE(8) *(note) }
  init_array ( TYPE=14 ) : { QUAD(14) }
  fini_array (TYPE = SHT_FINI_ARRAY) : { QUAD(15) }
}
```

When `sh_type` is specified, it is an error if an input section has a different type.

Our syntax is compatible with GNU ld 2.39 (https://sourceware.org/bugzilla/show_bug.cgi?id=28841).

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D118840
2022-02-17 12:10:58 -08:00
Fangrui Song
27bb799095 [ELF] Clean up headers. NFC 2022-02-07 21:53:34 -08:00
Alexandre Ganea
83d59e05b2 Re-land [LLD] Remove global state in lldCommon
Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.

See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html

The previous land f860fe362282ed69b9d4503a20e5d20b9a041189 caused issues in https://lab.llvm.org/buildbot/#/builders/123/builds/8383, fixed by 22ee510dac9440a74b2e5b3fe3ff13ccdbf55af3.

Differential Revision: https://reviews.llvm.org/D108850
2022-01-20 14:53:26 -05:00
Alexandre Ganea
e6b153947d Revert [LLD] Remove global state in lldCommon
It seems to be causing issues on https://lab.llvm.org/buildbot/#/builders/123/builds/8383
2022-01-16 11:03:06 -05:00
Alexandre Ganea
f860fe3622 [LLD] Remove global state in lldCommon
Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.

See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html

Differential Revision: https://reviews.llvm.org/D108850
2022-01-16 08:57:57 -05:00
Fangrui Song
64038ef8c3 [ELF] ScriptParser: change std::vector to SmallVector 2021-12-26 20:12:55 -08:00
Fangrui Song
a1c2ee0147 [ELF] LinkerScript/OutputSection: change other std::vector members to SmallVector
11+KiB smaller .text with both libc++ and libstdc++ builds.
2021-12-26 13:53:47 -08:00
Fangrui Song
7051aeef7a [ELF] Rename BaseCommand to SectionCommand. NFC
BaseCommand was picked when PHDRS/INSERT/etc were not implemented. Rename it to
SectionCommand to match `sectionCommands` and make it clear that the commands
are used in SECTIONS (except a special case for SymbolAssignment).

Also, improve naming of some BaseCommand variables (base -> cmd).
2021-11-25 20:24:23 -08:00
Fangrui Song
6188fd4957 [ELF] Rename OutputSection::sectionCommands to commands. NFC
This partially reverts r315409: the description applies to LinkerScript, but not
to OutputSection.

The name "sectionCommands" is used in both LinkerScript::sectionCommands and
OutputSection::sectionCommands, which may lead to confusion.
"commands" in OutputSection has no ambiguity because there are no other types
of commands.
2021-11-25 16:47:07 -08:00
Igor Kudrin
8cdf1c1edb [ELF] Support the "read-only" memory region attribute
The attribute 'r' allows (or disallows for the negative case) read-only
sections, i.e. ones without the SHF_WRITE flag, to be assigned to the
memory region. Before the patch, lld could put a section in the wrong
region or fail with "error: no memory region specified for section".

Differential Revision: https://reviews.llvm.org/D113771
2021-11-24 12:17:09 +07:00
Fangrui Song
bf6e259b21 [ELF] Update comments/diagnostics for some long options to use the canonical two-dash form
Rewrite some comments as appropriate.
2021-10-25 12:52:06 -07:00
Fangrui Song
2bf06d9345 [ELF] Support symbol names with space in linker script expressions
Fix PR51961

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D110490
2021-09-27 09:50:42 -07:00
Fangrui Song
00809c8889 [ELF] Apply version script patterns to non-default version symbols
Currently version script patterns are ignored for .symver produced
non-default version (single @) symbols. This makes such symbols
not localizable by `local:`, e.g.

```
.symver foo3_v1,foo3@v1
.globl foo_v1
foo3_v1:

ld.lld --version-script=a.ver -shared a.o
```

This patch adds the support:

* Move `config->versionDefinitions[VER_NDX_LOCAL].patterns` to `config->versionDefinitions[versionId].localPatterns`
* Rename `config->versionDefinitions[versionId].patterns` to `config->versionDefinitions[versionId].nonLocalPatterns`
* Allow `findAllByVersion` to find non-default version symbols when `includeNonDefault` is true. (Note: `symtab` keys do not have `@@`)
* Make each pattern check both the unversioned `pat.name` and the versioned `${pat.name}@${v.name}`
* `localPatterns` can localize `${pat.name}@${v.name}`. `nonLocalPatterns` can prevent localization by assigning `verdefIndex` (before `parseSymbolVersion`).

---

If a user notices new `undefined symbol` errors with a version script containing
`local: *;`, the issue is likely due to a missing `global:` pattern.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D107234
2021-08-04 23:52:56 -07:00
Fangrui Song
a533eb7423 Revert "[ELF] Apply version script patterns to non-default version symbols"
This reverts commit 7ed22a6fa90cbdc70d6806c1121a0c50c1978dce.

buf is not cleared so the commit misses some cases.
2021-08-04 23:52:55 -07:00
Fangrui Song
7ed22a6fa9 [ELF] Apply version script patterns to non-default version symbols
Currently version script patterns are ignored for .symver produced
non-default version (single @) symbols. This makes such symbols
not localizable by `local:`, e.g.

```
.symver foo3_v1,foo3@v1
.globl foo_v1
foo3_v1:

ld.lld --version-script=a.ver -shared a.o
# In a.out, foo3@v1 is incorrectly exported.
```

This patch adds the support:

* Move `config->versionDefinitions[VER_NDX_LOCAL].patterns` to `config->versionDefinitions[versionId].localPatterns`
* Rename `config->versionDefinitions[versionId].patterns` to `config->versionDefinitions[versionId].nonLocalPatterns`
* Allow `findAllByVersion` to find non-default version symbols when `includeNonDefault` is true. (Note: `symtab` keys do not have `@@`)
* Make each pattern check both the unversioned `pat.name` and the versioned `${pat.name}@${v.name}`
* `localPatterns` can localize `${pat.name}@${v.name}`. `nonLocalPatterns` can prevent localization by assigning `verdefIndex` (before `parseSymbolVersion`).

---

If a user notices new `undefined symbol` errors with a version script containing
`local: *;`, the issue is likely due to a missing `global:` pattern.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D107234
2021-08-04 09:02:11 -07:00
Fangrui Song
e7a7ad134f [ELF] Support quoted symbols in symbol assignments
glibc/elf/tst-absolute-zero-lib.lds uses `"absolute" = 0;`
2021-07-25 16:26:37 -07:00
Fangrui Song
03051f7ac8 [ELF] Preserve section order within an INSERT AFTER command
For
```
SECTIONS {
  text.0 : {}
  text.1 : {}
  text.2 : {}
} INSERT AFTER .data;
```

the current order is `.data text.2 text.1 text.0`. It makes more sense to
preserve the specified order and thus improve compatibility with GNU ld.

For
```
SECTIONS { text.0 : {} } INSERT AFTER .data;
SECTIONS { text.3 : {} } INSERT AFTER .data;
```

GNU ld somehow collects sections with `INSERT AFTER .data` together (IMO
inconsistent) but I think it makes more sense to execute the commands in order
and get `.data text.3 text.0` instead.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D105158
2021-06-30 11:35:50 -07:00
Fangrui Song
2508733e1b [ELF] --sysroot: change sysrooted script to not fall back for an absolute path
Modify the D13209 logic: for a script inside the sysroot, if an absolute path
does not exist, report an error instead of falling back to the path without the
sysroot prefix.

This matches GNU ld, which makes sense to me: we don't want to find an arbitrary
file in the host.

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D104894
2021-06-25 12:52:39 -07:00
Martin Storsjö
3c6f8ca7c9 [lld] Rename StringRef _lower() method calls to _insensitive() 2021-06-25 00:22:01 +03:00
Fangrui Song
899fdf548e [ELF] Add OVERWRITE_SECTIONS command
This implements https://sourceware.org/bugzilla/show_bug.cgi?id=26404

An `OVERWRITE_SECTIONS` command is a `SECTIONS` variant which contains several
output section descriptions. The output sections do not have specify an order.
Similar to `INSERT [BEFORE|AFTER]`, `LinkerScript::hasSectionsCommand` is not
set, so the built-in rules (see `docs/ELF/linker_script.rst`) still apply.
`OVERWRITE_SECTIONS` can be more convenient than `INSERT` because it does not
need an anchor section.

The initial syntax is intentionally narrow to facilitate backward compatible
extensions in the future. Symbol assignments cannot be used.

This feature is versatile. To list a few usage:

* Use `section : { KEEP(...) }` to retain input sections under GC
* Define encapsulation symbols (start/end) for an output section
* Use `section : ALIGN(...) : { ... }` to overalign an output section (similar to ld64 `-sectalign`)

When an output section is specified by both `OVERWRITE_SECTIONS` and
`INSERT`, `INSERT` is processed after overwrite sections. To make this work,
this patch changes `InsertCommand` to use name based matching instead of pointer
based matching. (This may cause a difference when `INSERT` moves one output
section more than once. Such duplicate commands should not be used in practice
(seems that in GNU ld the output sections may just disappear).)

A linker script can be used without -T/--script. The traditional `SECTIONS`
commands are concatenated, so a wrong rule can be more noticeable from the
section order. This feature if misused can be less noticeable, just like
`INSERT`.

Differential Revision: https://reviews.llvm.org/D103303
2021-06-13 12:41:11 -07:00
Fangrui Song
e4f385d894 [ELF] Support . and $ in symbol names in expressions
GNU ld supports `.` and `$` in symbol names while LLD doesn't support them in
`readPrimary` expressions. Using `.` can result in such an error:

```
https://github.com/ClangBuiltLinux/linux/issues/1318
ld.lld: error: ./arch/powerpc/kernel/vmlinux.lds:255: malformed number: .TOC.
>>>   __toc_ptr = (DEFINED (.TOC.) ? .TOC. : ADDR (.got)) + 0x8000;
```

Allow `.` (ppc64 special symbol `.TOC.`) and `$` (RISC-V special symbol `__global_pointer$`).

Change `diag[3-5].test` to use an invalid character `^`.

Note: GNU ld allows `~` in non-leading positions of a symbol name.  `~`
is not used in practice, conflicts with the unary operator, and can
cause some parsing difficulty, so this patch does not add it.

Differential Revision: https://reviews.llvm.org/D98306
2021-03-11 09:34:36 -08:00
Fangrui Song
eea34aae2e [ELF] Inspect -EL & -EB for OUTPUT_FORMAT(default, big, little)
Choose big if -EB is specified, little if -EL is specified, or default if neither is specified.
The new behavior matches GNU ld.

Fixes: https://github.com/ClangBuiltLinux/linux/issues/1025

Differential Revision: https://reviews.llvm.org/D96214
2021-02-08 10:34:57 -08:00
Fangrui Song
7605a9a009 [ELF] Support aarch64_be
This patch adds

* Big-endian values for `R_AARCH64_{ABS,PREL}{16,32,64}` and `R_AARCH64_PLT32`
* aarch64elfb & aarch64linuxb BFD emulations
* elf64-bigaarch64 output format (bfdname)

Link: https://github.com/ClangBuiltLinux/linux/issues/1288

Differential Revision: https://reviews.llvm.org/D96188
2021-02-08 08:55:29 -08:00