e44068cc12
Mach-O category merging can encounter Swift class references as an enclosing metadata symbol plus a non-zero addend after LTO removes the exact class-address alias. For example, a category can refer to a `CMf` symbol plus the offset of the class object within that metadata record. `tryGetSymbolAtIsecOffset()` previously resolved such a relocation to the enclosing symbol and discarded the residual addend. `getClassRo()` then read the class layout at the wrong address. For valid Swift metadata this can return null; before the defensive check in the first commit the linker dereferenced that result and crashed, while the check alone safely skipped a category that could have been merged. Preserve the class reference as a symbol and residual addend throughout: - category grouping; - class and metaclass RO-data lookup; - source-language detection; and - relocations synthesized for merged categories. An exact symbol at the target address is still preferred. When no exact alias survives, retain the offset from the closest containing symbol. The defensive checks remain in place for genuinely incomplete or unsupported metadata. The Swift regression now omits the exact class-address alias and points the category classlist directly into the enclosing metadata record, matching the shape observed after ThinLTO. Testing: - Release + assertions AArch64 LLVM/LLD build - focused `llvm-lit` coverage for the alias-free Swift metadata and missing-metadata cases - full Swift 6 application link with `-objc_category_merging` The application result is integration evidence for correctness and folding coverage |
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| clang | ||
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| cmake | ||
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| flang | ||
| flang-rt | ||
| libc | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libsycl | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llvm | ||
| llvm-libgcc | ||
| mlir | ||
| offload | ||
| openmp | ||
| orc-rt | ||
| polly | ||
| runtimes | ||
| third-party | ||
| utils | ||
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| .git-blame-ignore-revs | ||
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| .mailmap | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| LICENSE.TXT | ||
| pyproject.toml | ||
| README.md | ||
| SECURITY.md | ||
The LLVM Compiler Infrastructure
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called "LLVM". This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Getting the Source Code and Building LLVM
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
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