compiler-rt/www/index.html

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  15   <!--*********************************************************************-->
  16   <h1>"compiler-rt" runtime libraries</h1>
  17   <!--*********************************************************************-->
  18
  19   <p>The compiler-rt project consists of:
  20   <ul>
  21   <li>
  22     <p><b>builtins</b> - a simple library that provides an implementation
  23     of the low-level target-specific hooks required by code generation and
  24     other runtime components.  For example, when compiling for a 32-bit target,
  25     converting a double to a 64-bit unsigned integer is compiling into a runtime
  26     call to the "__fixunsdfdi" function.  The builtins library provides
  27     optimized implementations of this and other low-level routines, either in
  28     target-independent C form, or as a heavily-optimized assembly.</p>
  29     <p>builtins provides full support for the libgcc interfaces on supported
  30     targets and high performance hand tuned implementations of commonly used
  31     functions like __floatundidf in assembly that are dramatically faster than
  32     the libgcc implementations. It should be very easy to bring builtins to
  33     support a new target by adding the new routines needed by that target.</p>
  34   </li>
  35   <li>
  36     <b>sanitizer runtimes</b> - runtime libraries that are required to run
  37     the code with sanitizer instrumentation. This includes runtimes for:
  38     <ul>
  39     <li><a href="https://clang.llvm.org/docs/AddressSanitizer.html">AddressSanitizer</a></li>
  40     <li><a href="https://clang.llvm.org/docs/ThreadSanitizer.html">ThreadSanitizer</a></li>
  41     <li><a href="https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html">UndefinedBehaviorSanitizer</a></li>
  42     <li><a href="https://clang.llvm.org/docs/MemorySanitizer.html">MemorySanitizer</a></li>
  43     <li><a href="https://clang.llvm.org/docs/LeakSanitizer.html">LeakSanitizer</a></li>
  44     <li><a href="https://clang.llvm.org/docs/DataFlowSanitizer.html">DataFlowSanitizer</a></li>
  45     </ul>
  46   </li>
  47   <li>
  48     <b>profile</b> - library which is used to collect coverage information.
  49   </li>
  50   <li>
  51     <b>BlocksRuntime</b> - a target-independent implementation of Apple "Blocks"
  52     runtime interfaces.
  53   </li>
  54   </ul>
  55   </p>
  56
  57   <p>All of the code in the compiler-rt project is <a
  58      href="https://llvm.org/docs/DeveloperPolicy.html#copyright-license-and-patents">dual licensed</a>
  59      under the MIT license and the UIUC License (a BSD-like license).</p>
  60
  61   <!--=====================================================================-->
  62   <h2 id="users">Clients</h2>
  63   <!--=====================================================================-->
  64
  65   <p>Currently compiler-rt is primarily used by
  66     the <a href="https://clang.llvm.org">Clang</a>
  67     and <a href="https://llvm.org">LLVM</a> projects as the implementation for
  68     the runtime compiler support libraries. For more information on using
  69     compiler-rt with Clang, please see the Clang
  70     <a href="https://clang.llvm.org/get_started.html">Getting Started</a>
  71     page.</p>
  72
  73   <!--=====================================================================-->
  74   <h2 id="requirements">Platform Support</h2>
  75   <!--=====================================================================-->
  76
  77    <p><b>builtins</b> is known to work on the following platforms:</p>
  78    <ul>
  79    <li>Machine Architectures: i386, X86-64, SPARC64, ARM, PowerPC, PowerPC 64.</li>
  80    <li>OS: DragonFlyBSD, FreeBSD, NetBSD, OpenBSD, Linux, Darwin.</li>
  81    </ul>
  82
  83    <p>Most sanitizer runtimes are supported only on Linux x86-64. See tool-specific
  84    pages in <a href="https://clang.llvm.org/docs/index.html">Clang docs</a> for more
  85    details.</p>
  86
  87   <!--=====================================================================-->
  88   <h2 id="dir-structure">Source Structure</h2>
  89   <!--=====================================================================-->
  90
  91    <p>A short explanation of the directory structure of compiler-rt:</p>
  92
  93    <p>For testing it is possible to build a generic library and an optimized library.
  94        The optimized library is formed by overlaying the optimized versions onto the generic library.
  95        Of course, some architectures have additional functions,
  96        so the optimized library may have functions not found in the generic version.</p>
  97
  98    <ul>
  99     <li> include/ contains headers that can be included in user programs (for example,
 100          users may directly call certain function from sanitizer runtimes).</li>
 101     <li> lib/ contains libraries implementations. </li>
 102     <li> lib/builtins is a generic portable implementation of <b>builtins</b> routines.</li>
 103     <li> lib/builtins/(arch) has optimized versions of some routines
 104          for the supported architectures.</li>
 105     <li> test/ contains test suites for compiler-rt runtimes.</li>
 106    </ul>
 107
 108   <!--=====================================================================-->
 109   <h2>Get it and get involved!</h2>
 110   <!--=====================================================================-->
 111
 112   <p>Generally, you need to build LLVM/Clang in order to build compiler-rt. You
 113     can build it either together with llvm and clang, or separately.
 114
 115   <p>To build it together, simply add compiler-rt to the -DLLVM_ENABLE_RUNTIMES= option to
 116     cmake.
 117
 118   <p>To build it separately, first
 119   <a href="https://llvm.org/docs/CMake.html#quick-start">build LLVM</a>
 120   separately to get llvm-config binary, and then run:
 121
 122   <ul>
 123   <li>cd llvm-project</li>
 124   <li>mkdir build-compiler-rt</li>
 125   <li>cd build-compiler-rt</li>
 126   <li>cmake ../compiler-rt -DLLVM_CONFIG_PATH=/path/to/llvm-config</li>
 127   <li>make</li>
 128   </ul>
 129
 130   <p>Tests for sanitizer runtimes are ported to
 131   <a href="https://llvm.org/docs/CommandGuide/lit.html">llvm-lit</a> and are
 132   run by <b>make check-all</b> command in LLVM/Clang/compiler-rt build tree.</p>
 133
 134   <p>compiler-rt libraries are installed to the system with <b>make install</b>
 135   command in either LLVM/Clang/compiler-rt or standalone
 136   compiler-rt build tree.</p>
 137
 138   <p>If you have questions, please ask on the <a href="https://discourse.llvm.org/c/runtimes/64">
 139    Discourse forums</a> under the Runtime category.  Commits to compiler-rt are automatically
 140    sent to the <a
 141   href="https://lists.llvm.org/mailman/listinfo/llvm-commits">llvm-commits</a>
 142     mailing list.</p>
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