4db63ee847
The function converts from IPv4/6 addresses to their string forms. The complication comes from the v6 part due to address compression and v4-mapping. The traditional implementation of this is to sprintf the address into a temporary buffer. We cannot do that here due to the ban on calling other entry points. Using the lower-level constructs is possible, but a straight forward application of IntegerToString does not result in particularly impressive performance: 50%-100% slower than what's in this patch (and slower than glibc). It also doesn't make the code much smaller as the majority of it is dedicated to v6 compression. The IPv6 implementation uses a temporary buffer, but it also has a fast-path which skips the buffer if its size is guaranteed to be sufficient. The IPv4 implementation also has a fast path, but the fallback here is to compute the precise length of the string instead (the buffer option was slower and IPv4 makes it easier to compute the precise length). The v6 compression code is unrolled to make it easier to optimize. While it is possible to write a single printing loop that handles all cases, its branchiness does not make it amenable for optimization. The resulting function is faster than its glibc counterpart, though the exact ratio varies depending on the input: - random IPv4: 15% faster - random IPv6: 6% faster - "::": 50% faster |
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| bolt | ||
| clang | ||
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| cmake | ||
| compiler-rt | ||
| cross-project-tests | ||
| flang | ||
| flang-rt | ||
| libc | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libsycl | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llvm | ||
| llvm-libgcc | ||
| mlir | ||
| offload | ||
| openmp | ||
| orc-rt | ||
| polly | ||
| runtimes | ||
| third-party | ||
| utils | ||
| .clang-format | ||
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| .clang-tidy | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
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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.
Getting in touch
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
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