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[LLD] Set alignment as part of Characteristics in TLS table. #81

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Merged
merged 3 commits into from
Oct 17, 2020

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@luqmana luqmana commented Oct 17, 2020

… test.

Akin to dumpbin's /TLS option, this will print out the TLS directory, if
present, in the image.

Example output:
```
> llvm-readobj --coff-tls-directory test.exe
File: test.exe
Format: COFF-x86-64
Arch: x86_64
AddressSize: 64bit
TLSDirectory {
  StartAddressOfRawData: 0x140004000
  EndAddressOfRawData: 0x140004040
  AddressOfIndex: 0x140002000
  AddressOfCallBacks: 0x0
  SizeOfZeroFill: 0x0
  Characteristics [ (0x0)
  ]
}
```

Reviewed By: jhenderson, grimar

Differential Revision: https://reviews.llvm.org/D88635
Fixes https://bugs.llvm.org/show_bug.cgi?id=46473

LLD wasn't previously specifying any specific alignment in the TLS table's Characteristics field so the loader would just assume the default value (16 bytes). This works most of the time except if you have thread locals that want specific higher alignments (e.g. 32 as in the bug) *even* if they specify an alignment on the thread local. This change updates LLD to take the max alignment from tls section.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D88637
@nikic nikic merged commit 655a146 into rust-lang:rustc/11.0-2020-10-12 Oct 17, 2020
@luqmana luqmana deleted the rust-lld-tls-alignment branch October 17, 2020 08:38
bors added a commit to rust-lang-ci/rust that referenced this pull request Oct 17, 2020
LLVM: Backport fix for LLD COFF TLS Alignment.

Update LLVM submodule to pull in changes from rust-lang/llvm-project#81.

Fixes rust-lang#72145.
nikic pushed a commit to nikic/llvm-project that referenced this pull request Sep 22, 2023
llvm#67069)

We noticed some performance issue while in lldb-vscode for grabing the
name of the SBValue. Profiling shows SBValue::GetName() can cause
synthetic children provider of shared/unique_ptr to deference underlying
object and complete it type.

This patch lazily moves the dereference from synthetic child provider's
Update() method to GetChildAtIndex() so that SBValue::GetName() won't
trigger the slow code path.

Here is the culprit slow code path:
```
...
frame rust-lang#59: 0x00007ff4102e0660 liblldb.so.15`SymbolFileDWARF::CompleteType(this=<unavailable>, compiler_type=0x00007ffdd9829450) at SymbolFileDWARF.cpp:1567:25 [opt]
...
frame rust-lang#67: 0x00007ff40fdf9bd4 liblldb.so.15`lldb_private::ValueObject::Dereference(this=0x0000022bb5dfe980, error=0x00007ffdd9829970) at ValueObject.cpp:2672:41 [opt]
frame rust-lang#68: 0x00007ff41011bb0a liblldb.so.15`(anonymous namespace)::LibStdcppSharedPtrSyntheticFrontEnd::Update(this=0x000002298fb94380) at LibStdcpp.cpp:403:40 [opt]
frame rust-lang#69: 0x00007ff41011af9a liblldb.so.15`lldb_private::formatters::LibStdcppSharedPtrSyntheticFrontEndCreator(lldb_private::CXXSyntheticChildren*, std::shared_ptr<lldb_private::ValueObject>) [inlined] (anonymous namespace)::LibStdcppSharedPtrSyntheticFrontEnd::LibStdcppSharedPtrSyntheticFrontEnd(this=0x000002298fb94380, valobj_sp=<unavailable>) at LibStdcpp.cpp:371:5 [opt]
...
frame rust-lang#78: 0x00007ff40fdf6e42 liblldb.so.15`lldb_private::ValueObject::CalculateSyntheticValue(this=0x000002296c66a500) at ValueObject.cpp:1836:27 [opt]
frame rust-lang#79: 0x00007ff40fdf1939 liblldb.so.15`lldb_private::ValueObject::GetSyntheticValue(this=<unavailable>) at ValueObject.cpp:1867:3 [opt]
frame rust-lang#80: 0x00007ff40fc89008 liblldb.so.15`ValueImpl::GetSP(this=0x0000022c71b90de0, stop_locker=0x00007ffdd9829d00, lock=0x00007ffdd9829d08, error=0x00007ffdd9829d18) at SBValue.cpp:141:46 [opt]
frame rust-lang#81: 0x00007ff40fc7d82a liblldb.so.15`lldb::SBValue::GetSP(ValueLocker&) const [inlined] ValueLocker::GetLockedSP(this=0x00007ffdd9829d00, in_value=<unavailable>) at SBValue.cpp:208:21 [opt]
frame rust-lang#82: 0x00007ff40fc7d817 liblldb.so.15`lldb::SBValue::GetSP(this=0x00007ffdd9829d90, locker=0x00007ffdd9829d00) const at SBValue.cpp:1047:17 [opt]
frame rust-lang#83: 0x00007ff40fc7da6f liblldb.so.15`lldb::SBValue::GetName(this=0x00007ffdd9829d90) at SBValue.cpp:294:32 [opt]
...
```

Differential Revision: https://reviews.llvm.org/D159542
vext01 added a commit to vext01/llvm-project that referenced this pull request Sep 26, 2023
81: Start serialising our own Yk IR. r=ltratt a=vext01



Co-authored-by: Edd Barrett <[email protected]>
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