f4ba6a654d
Refer: 7.3.1 from [ISO SPEC](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3220.pdf) I have added complex variants of F16 and F128 in libc doc but have omitted support for them since we will have to first investigate how their support matrix for clang and gcc looks like, and then add header guards for them accordingly. Planning to add them in follow up PRs once this gets landed.
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==================
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The LLVM C Library
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==================
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.. note::
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LLVM-libc is not fully complete right now. Some programs may fail to build due
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to missing functions (especially C++ ones). If you would like to help us
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finish LLVM-libc, check out "Contributing to the libc project" in the sidebar
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or ask on discord.
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Introduction
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============
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LLVM-libc aspires to a unique place in the software ecosystem. The goals are:
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- Fully compliant with current C standards (C17 and upcoming C2x) and POSIX.
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- Easily decomposed and embedded: Supplement or replace system C library
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functionality easily. This is useful to get consistent math precision across
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systems, or updated memory operations for newer microarchitectures. These
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pieces will work on Linux, MacOS, Windows, and Fuchsia.
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- The creation of fully static binaries without license implications.
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- Increase whole program optimization opportunities for static binaries through
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ability to inline math and memory operations.
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- Reduce coding errors by coding in modern C++ through the use of lightweight
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containers during coding that can be optimized away at runtime.
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- Permit fuzzing and sanitizer instrumentation of user binaries including the
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libc functions.
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- A complete testsuite that tests both the public interface and internal
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algorithms.
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- `Fuzzing`__
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.. __: https://github.com/llvm/llvm-project/tree/main/libc/fuzzing
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Platform Support
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================
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Most development is currently targeting Linux on x86_64, aarch64, arm, and
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RISC-V. Embedded/baremetal targets are supported on arm and RISC-V, and Windows
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and MacOS have limited support (may be broken). The Fuchsia platform is
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slowly replacing functions from its bundled libc with functions from this
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project.
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ABI Compatibility
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=================
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The libc is written to be ABI independent. Interfaces are generated using
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headergen, so supporting arbitrary ABIs is possible. In it's initial
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stages there is no ABI stability in any form.
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.. toctree::
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:hidden:
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:maxdepth: 2
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:caption: Using
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usage_modes
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overlay_mode
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fullbuild_mode
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configure
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gpu/index.rst
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.. toctree::
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:hidden:
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:maxdepth: 1
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:caption: Status
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compiler_support
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date_and_time
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math/index.rst
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strings
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stdio
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stdbit
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fenv
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libc_search
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c23
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ctype
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complex
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signal
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threads
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setjmp
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.. toctree::
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:hidden:
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:maxdepth: 1
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:caption: Development
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build_and_test
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dev/index.rst
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porting
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contributing
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talks
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.. toctree::
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:hidden:
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:maxdepth: 1
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:caption: External Links
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Source Code <https://github.com/llvm/llvm-project/tree/main/libc>
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Bug Reports <https://github.com/llvm/llvm-project/labels/libc>
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Discourse <https://discourse.llvm.org/c/runtimes/libc>
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Join the Discord <https://discord.gg/xS7Z362>
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Discord Channel <https://discord.com/channels/636084430946959380/636732994891284500>
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Buildbot <https://lab.llvm.org/buildbot/#/builders?tags=libc>
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