[llvm-objdump][X86] Add @plt symbols for .plt.got

If a symbol needs both JUMP_SLOT and GLOB_DAT relocations, there is a
minor linker optimization to keep just GLOB_DAT. This optimization
is only imp

[llvm-objdump][X86] Add @plt symbols for .plt.got

If a symbol needs both JUMP_SLOT and GLOB_DAT relocations, there is a
minor linker optimization to keep just GLOB_DAT. This optimization
is only implemented by GNU ld's x86 port and mold.
https://maskray.me/blog/2021-08-29-all-about-global-offset-table#combining-.got-and-.got.plt

With the optimizing, the PLT entry is placed in .plt.got and the
associated GOTPLT entry is placed in .got (ld.bfd -z now) or .got.plt (ld.bfd -z lazy).
The relocation is in .rel[a].dyn.

This patch synthesizes `symbol@plt` labels for these .plt.got entries.

Example:
```
cat > a.s <<e
.globl _start; _start:
mov combined0@gotpcrel(%rip), %rax; mov combined1@gotpcrel(%rip), %rax
call combined0@plt; call combined1@plt
call foo0@plt; call foo1@plt
e
cat > b.s <<e
.globl foo0, foo1, combined0, combined1
foo0: foo1: combined0: combined1:
e
gcc -fuse-ld=bfd -shared b.s -o b.so
gcc -fuse-ld=bfd -pie -nostdlib a.s b.so -o a
```

```
Disassembly of section .plt:

0000000000001000 <.plt>:
1000: ff 35 ea 1f 00 00 pushq 0x1fea(%rip) # 0x2ff0 <_GLOBAL_OFFSET_TABLE_+0x8>
1006: ff 25 ec 1f 00 00 jmpq *0x1fec(%rip) # 0x2ff8 <_GLOBAL_OFFSET_TABLE_+0x10>
100c: 0f 1f 40 00 nopl (%rax)

0000000000001010 <foo1@plt>:
1010: ff 25 ea 1f 00 00 jmpq *0x1fea(%rip) # 0x3000 <_GLOBAL_OFFSET_TABLE_+0x18>
1016: 68 00 00 00 00 pushq $0x0
101b: e9 e0 ff ff ff jmp 0x1000 <.plt>

0000000000001020 <foo0@plt>:
1020: ff 25 e2 1f 00 00 jmpq *0x1fe2(%rip) # 0x3008 <_GLOBAL_OFFSET_TABLE_+0x20>
1026: 68 01 00 00 00 pushq $0x1
102b: e9 d0 ff ff ff jmp 0x1000 <.plt>

Disassembly of section .plt.got:

0000000000001030 <combined0@plt>:
1030: ff 25 a2 1f 00 00 jmpq *0x1fa2(%rip) # 0x2fd8 <foo1+0x2fd8>
1036: 66 90 nop

0000000000001038 <combined1@plt>:
1038: ff 25 a2 1f 00 00 jmpq *0x1fa2(%rip) # 0x2fe0 <foo1+0x2fe0>
103e: 66 90 nop
```

For x86-32, with -z now, if we remove `foo0` and `foo1`, the absence of regular
PLT will cause GNU ld to omit .got.plt, and our code cannot synthesize @plt
labels. This is an extreme corner case that almost never happens in practice (to
trigger the case, ensure every PLT symbol has been taken address). To fix it, we
can get the `_GLOBAL_OFFSET_TABLE_` symbol value, but the complexity is not
worth it.

Close https://github.com/llvm/llvm-project/issues/62537

Reviewed By: bd1976llvm

Differential Revision: https://reviews.llvm.org/D149817

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[llvm-objdump][RISCV] Use new common method to parse ARCH RISCV attribute

Differential Revision: https://reviews.llvm.org/D139553

Remove redundant .c_str() and .get() calls

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D139485

Cleanup include: DebugInfo/Symbolize

Estimation of the impact on preprocessor output
after: 1067349756
before:1067487786

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-

Cleanup include: DebugInfo/Symbolize

Estimation of the impact on preprocessor output
after: 1067349756
before:1067487786

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120433

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Avoid by-value copies of referenced objects

These were detected by the new -Wauto-by-value-copy (D114989) warning, these by-value
constant copies need only be references.

Reviewed By: aaron.ballman

Avoid by-value copies of referenced objects

These were detected by the new -Wauto-by-value-copy (D114989) warning, these by-value
constant copies need only be references.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D114990

show more ...

Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually us

Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454

show more ...

[MC] Refactor MCObjectFileInfo initialization and allow targets to create MCObjectFileInfo

This makes it possible for targets to define their own MCObjectFileInfo.
This MCObjectFileInfo is then used

[MC] Refactor MCObjectFileInfo initialization and allow targets to create MCObjectFileInfo

This makes it possible for targets to define their own MCObjectFileInfo.
This MCObjectFileInfo is then used to determine things like section alignment.

This is a follow up to D101462 and prepares for the RISCV backend defining the
text section alignment depending on the enabled extensions.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101921

show more ...

[MC] Untangle MCContext and MCObjectFileInfo

This untangles the MCContext and the MCObjectFileInfo. There is a circular
dependency between MCContext and MCObjectFileInfo. Currently this dependency
a

[MC] Untangle MCContext and MCObjectFileInfo

This untangles the MCContext and the MCObjectFileInfo. There is a circular
dependency between MCContext and MCObjectFileInfo. Currently this dependency
also exists during construction: You can't contruct a MOFI without a MCContext
without constructing the MCContext with a dummy version of that MOFI first.
This removes this dependency during construction. In a perfect world,
MCObjectFileInfo wouldn't depend on MCContext at all, but only be stored in the
MCContext, like other MC information. This is future work.

This also shifts/adds more information to the MCContext making it more
available to the different targets. Namely:

- TargetTriple
- ObjectFileType
- SubtargetInfo

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101462

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[llvm-cfi-verify] Set UseSymbolTable to false

parseSectionContents expects to skip regions not described by DWARF. With my
pending DebugInfo/Symbolize change, the filename can be recovered and ther

[llvm-cfi-verify] Set UseSymbolTable to false

parseSectionContents expects to skip regions not described by DWARF. With my
pending DebugInfo/Symbolize change, the filename can be recovered and there
will be more IndirectInstructions entries.

show more ...

[llvm] Use *Set::contains (NFC)

[llvm-objdump] Change symbol name/PLT decoding errors to warnings

If the referenced symbol of a J[U]MP_SLOT is invalid (e.g. symbol index 0), llvm-objdump -d will bail out:

```
error: 'a': st_name

[llvm-objdump] Change symbol name/PLT decoding errors to warnings

If the referenced symbol of a J[U]MP_SLOT is invalid (e.g. symbol index 0), llvm-objdump -d will bail out:

```
error: 'a': st_name (0x326600) is past the end of the string table of size 0x7
```

where 0x326600 is the st_name field of the first entry past the end of .symtab

Change it to a warning to continue dumping.
`X86/plt.test` uses a prebuilt executable, so I pick `ELF/AArch64/plt.test`
which has a YAML input and can be easily modified.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D85623

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Revert "Remove redundant "std::move"s in return statements"

The build failed with

error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a7936bf85aa68aef94bd40c3b

Revert "Remove redundant "std::move"s in return statements"

The build failed with

error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a7936bf85aa68aef94bd40c3ba77d8ddf2.

show more ...

Remove redundant "std::move"s in return statements

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly m

Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.

show more ...

[Disassembler] Delete the VStream parameter of MCDisassembler::getInstruction()

The argument is llvm::null() everywhere except llvm::errs() in
llvm-objdump in -DLLVM_ENABLE_ASSERTIONS=On builds. It

[Disassembler] Delete the VStream parameter of MCDisassembler::getInstruction()

The argument is llvm::null() everywhere except llvm::errs() in
llvm-objdump in -DLLVM_ENABLE_ASSERTIONS=On builds. It is used by no
target but X86 in -DLLVM_ENABLE_ASSERTIONS=On builds.

If we ever have the needs to add verbose log to disassemblers, we can
record log with a member function, instead of passing it around as an
argument.

show more ...

[MC] Add parameter `Address` to MCInstPrinter::printInst

printInst prints a branch/call instruction as `b offset` (there are many
variants on various targets) instead of `b address`.

It is a conven

[MC] Add parameter `Address` to MCInstPrinter::printInst

printInst prints a branch/call instruction as `b offset` (there are many
variants on various targets) instead of `b address`.

It is a convention to use address instead of offset in most external
symbolizers/disassemblers. This difference makes `llvm-objdump -d`
output unsatisfactory.

Add `uint64_t Address` to printInst(), so that it can pass the argument to
printInstruction(). `raw_ostream &OS` is moved to the last to be
consistent with other print* methods.

The next step is to pass `Address` to printInstruction() (generated by
tablegen from the instruction set description). We can gradually migrate
targets to print addresses instead of offsets.

In any case, downstream projects which don't know `Address` can pass 0 as
the argument.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D72172

show more ...

[Mips] Use appropriate private label prefix based on Mips ABI

MipsMCAsmInfo was using '$' prefix for Mips32 and '.L' for Mips64
regardless of -target-abi option. By passing MCTargetOptions to MCAsmI

[Mips] Use appropriate private label prefix based on Mips ABI

MipsMCAsmInfo was using '$' prefix for Mips32 and '.L' for Mips64
regardless of -target-abi option. By passing MCTargetOptions to MCAsmInfo
we can find out Mips ABI and pick appropriate prefix.

Tags: #llvm, #clang, #lldb

Differential Revision: https://reviews.llvm.org/D66795

show more ...

[llvm-objdump] Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprecht, grimar

Reviewed

[llvm-objdump] Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprecht, grimar

Reviewed By: jhenderson, grimar

Subscribers: RKSimon, MaskRay, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62462

llvm-svn: 368963

show more ...

Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"

Changes: no changes. A fix for the clang code will be landed right on top.

Original commit message:

SectionRef

Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"

Changes: no changes. A fix for the clang code will be landed right on top.

Original commit message:

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368826

show more ...

Revert r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"

It broke clang BB: http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/16455

llvm-svn: 368813

[llvm/Object] - Convert SectionRef::getName() to return Expected<>

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user

[llvm/Object] - Convert SectionRef::getName() to return Expected<>

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368812

show more ...

Revert "[llvm-objdump] Re-commit r367284."

This reverts r367776 (git commit d34099926e909390cb0254bebb4b7f5cf15467c7).
My changes to llvm-objdump tests caused them to fail on windows:
http://lab.llv

Revert "[llvm-objdump] Re-commit r367284."

This reverts r367776 (git commit d34099926e909390cb0254bebb4b7f5cf15467c7).
My changes to llvm-objdump tests caused them to fail on windows:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/27368

llvm-svn: 367816

show more ...

[llvm-objdump] Re-commit r367284.

Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprech

[llvm-objdump] Re-commit r367284.

Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprecht, grimar

Reviewed By: jhenderson, grimar

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62462

llvm-svn: 367776

show more ...

Revert "[llvm-objdump] Add warning messages if disassembly + source for problematic inputs"

This reverts r367284 (git commit b1cbe51bdf44098c74f5c74b7bcd8c041a7c6772).
My changes to LLVMSymbolizer c

Revert "[llvm-objdump] Add warning messages if disassembly + source for problematic inputs"

This reverts r367284 (git commit b1cbe51bdf44098c74f5c74b7bcd8c041a7c6772).
My changes to LLVMSymbolizer caused a test to fail:
http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29488

llvm-svn: 367286

show more ...

[llvm-objdump] Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprecht, grimar

Reviewed

[llvm-objdump] Add warning messages if disassembly + source for problematic inputs

Summary: Addresses https://bugs.llvm.org/show_bug.cgi?id=41905

Reviewers: jhenderson, rupprecht, grimar

Reviewed By: jhenderson, grimar

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62462

llvm-svn: 367284

show more ...