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Fangrui Song 345f59667d [ELF] Rename .plt to .iplt and decrease EM_PPC{,64} alignment of .glink to 4
GNU ld creates the synthetic section .iplt, and has a built-in linker
script that assigns .iplt to the output section .plt . There is no
output section named .iplt .

Making .iplt an output section actually has a benefit that makes the
tricky toolchain feature stand out. Symbolizers don't have to deal with
mixed PLT entries (e.g. llvm-objdump -d incorrectly annotates such jump
targets).

On EM_PPC{,64}, .glink contains a PLT resolver and a series of jump
instructions. The 4-byte entry size makes it unnecessary to have an
alignment of 16.

Mark ppc32-gnu-ifunc.s and ppc32-gnu-ifunc-nonpreemptable.s as `XFAIL: *`.
They test IPLT on EM_PPC, which never works.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D71520
2019-12-17 00:15:59 -08:00
clang [MinGW] Implicitly add .exe suffix if not provided 2019-12-17 10:08:39 +02:00
clang-tools-extra Revert "[clangd] Reapply b60896fad9 Fall back to selecting token-before-cursor if token-after-cursor fails." 2019-12-16 19:07:49 +01:00
compiler-rt [sanitizer] Construct InternalMmapVector without memory allocation. 2019-12-17 15:03:23 +07:00
debuginfo-tests [debuginfo] Update test to account for missing __debug_macinfo 2019-11-11 10:40:47 -08:00
libc [libc] Add implementation of errno and define the other macros of errno.h. 2019-12-09 13:34:08 -08:00
libclc libclc: Drop the old python based build system 2019-11-08 09:59:40 -05:00
libcxx [libc++] Add __default_init_tag to basic_string constructors 2019-12-16 19:04:09 -05:00
libcxxabi [libc++abi] Fix non-constant initialization of default terminate 2019-12-11 20:32:14 -05:00
libunwind [libunwind][RISCV] Add 64-bit RISC-V support 2019-12-16 16:36:56 +00:00
lld [ELF] Rename .plt to .iplt and decrease EM_PPC{,64} alignment of .glink to 4 2019-12-17 00:15:59 -08:00
lldb [lldb][NFC] Make clang-format happy by removing trailing space in ArchSpec.cpp 2019-12-17 09:13:48 +01:00
llgo IR: Support parsing numeric block ids, and emit them in textual output. 2019-03-22 18:27:13 +00:00
llvm [lit] [windows] Make sure to convert all path separators to backslashes in NT style \\?\... paths 2019-12-17 10:08:53 +02:00
openmp [libomptarget][nfc] Move timer functions behind target_impl 2019-12-17 02:22:29 +00:00
parallel-libs Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
polly [IR] Include more target specific intrinsic headers 2019-12-14 19:19:35 -08:00
pstl [pstl] Allow customizing whether per-TU insulation is provided 2019-08-13 12:49:00 +00:00
.arcconfig Update monorepo .arcconfig with new project callsign. 2019-01-31 14:34:59 +00:00
.clang-format Add .clang-tidy and .clang-format files to the toplevel of the 2019-01-29 16:43:16 +00:00
.clang-tidy Disable tidy checks with too many hits 2019-02-01 11:20:13 +00:00
.git-blame-ignore-revs Add LLDB reformatting to .git-blame-ignore-revs 2019-09-04 09:31:55 +00:00
.gitignore Add a newline at the end of the file 2019-09-04 06:33:46 +00:00
CONTRIBUTING.md Add contributing info to CONTRIBUTING.md and README.md 2019-12-02 15:47:15 +00:00
README.md Add contributing info to CONTRIBUTING.md and README.md 2019-12-02 15:47:15 +00:00

README.md

The LLVM Compiler Infrastructure

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.

The README briefly describes how to get started with building LLVM. For more information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting Started with the LLVM System

Taken from https://llvm.org/docs/GettingStarted.html.

Overview

Welcome to the LLVM project!

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 converts it into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer. It also contains basic regression tests.

C-like languages use the Clang front end. 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

The LLVM Getting Started documentation may be out of date. The Clang Getting Started page might have more accurate information.

This is an example workflow and configuration to get and build the LLVM source:

  1. Checkout LLVM (including related subprojects like Clang):

    • git clone https://github.com/llvm/llvm-project.git

    • Or, on windows, git clone --config core.autocrlf=false https://github.com/llvm/llvm-project.git

  2. Configure and build LLVM and Clang:

    • cd llvm-project

    • mkdir build

    • cd build

    • cmake -G <generator> [options] ../llvm

      Some common generators are:

      • Ninja --- for generating Ninja build files. Most llvm developers use Ninja.
      • Unix Makefiles --- for generating make-compatible parallel makefiles.
      • Visual Studio --- for generating Visual Studio projects and solutions.
      • Xcode --- for generating Xcode projects.

      Some Common options:

      • -DLLVM_ENABLE_PROJECTS='...' --- semicolon-separated list of the LLVM subprojects you'd like to additionally build. Can include any of: clang, clang-tools-extra, libcxx, libcxxabi, libunwind, lldb, compiler-rt, lld, polly, or debuginfo-tests.

        For example, to build LLVM, Clang, libcxx, and libcxxabi, use -DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi".

      • -DCMAKE_INSTALL_PREFIX=directory --- Specify for directory the full pathname of where you want the LLVM tools and libraries to be installed (default /usr/local).

      • -DCMAKE_BUILD_TYPE=type --- Valid options for type are Debug, Release, RelWithDebInfo, and MinSizeRel. Default is Debug.

      • -DLLVM_ENABLE_ASSERTIONS=On --- Compile with assertion checks enabled (default is Yes for Debug builds, No for all other build types).

    • Run your build tool of choice!

      • The default target (i.e. ninja or make) will build all of LLVM.

      • The check-all target (i.e. ninja check-all) will run the regression tests to ensure everything is in working order.

      • CMake will generate build targets for each tool and library, and most LLVM sub-projects generate their own check-<project> target.

      • Running a serial build will be slow. To improve speed, try running a parallel build. That's done by default in Ninja; for make, use make -j NNN (NNN is the number of parallel jobs, use e.g. number of CPUs you have.)

    • For more information see CMake

Consult the Getting Started with LLVM page for detailed information on configuring and compiling LLVM. You can visit Directory Layout to learn about the layout of the source code tree.