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Juneyoung Lee 578d2e2cb1 [llvm-extract] Add -keep-const-init commandline option
Summary:
This adds -keep-const-init option to llvm-extract which preserves initializers of
used global constants.

For example:

```
$ cat a.ll
@g = constant i32 0
define i32 @f() {
  %v = load i32, i32* @g
  ret i32 %v
}

$ llvm-extract --func=f a.ll -S -o -
@g = external constant i32
define i32 @f() { .. }

$ llvm-extract --func=f a.ll -keep-const-init -S -o -
@g = constant i32 0
define i32 @f() { .. }
```

This option is useful in checking whether a function that uses a constant global is optimized correctly.

Reviewers: jsji, MaskRay, david2050

Reviewed By: MaskRay

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73833
2020-02-03 14:30:28 +09:00
clang [Driver] Fix fsemantic-interposition.c for Windows and Darwin 2020-02-02 20:55:24 -08:00
clang-tools-extra Fixed typo in CTE release notes failing build 2020-02-02 21:51:34 +00:00
compiler-rt [CMake] compiler-rt: Add COMPILER_RT_BUILTINS_ENABLE_PIC 2020-01-31 15:57:18 -08:00
debuginfo-tests Add GDB pretty printers for llvm::ilist, llvm::simple_ilist, and llvm::ilist_node. 2020-01-30 09:35:49 +01:00
libc [libc] Use cpp::Array instead of cpp::ArrayRef in memory/utils_test. 2020-01-31 11:45:09 -08:00
libclc libclc: Drop the old python based build system 2019-11-08 09:59:40 -05:00
libcxx [libcxx] [test] Update msvc_stdlib_force_include.h. 2020-01-31 16:38:01 -08:00
libcxxabi [libc++abi] Bump PACKAGE_VERSION 2020-01-30 12:18:24 -08:00
libunwind [libunwind] Treat assembly files as C on mingw 2020-01-27 09:04:58 +02:00
lld [ELF][Mips] Drop an unneeded config->relocatable check 2020-01-31 21:00:28 -08:00
lldb [lldb] Remove LanguageRuntime::GetOverrideExprOptions 2020-01-31 22:05:23 -08:00
llgo IR: Support parsing numeric block ids, and emit them in textual output. 2019-03-22 18:27:13 +00:00
llvm [llvm-extract] Add -keep-const-init commandline option 2020-02-03 14:30:28 +09:00
mlir [mlir][Linalg][doc] Add Design Document for the Linalg Dialect 2020-02-02 14:55:35 -05:00
openmp Revert "[nfc][libomptarget] Remove SHARED annotation from local variables" 2020-01-27 20:05:17 +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 Fix polly build after StringRef change. 2020-01-28 19:44:20 -08:00
pstl Bump the trunk major version to 11 2020-01-15 13:38:01 +01:00
.arcconfig Include phabricator.uri in .arcconfig 2020-01-23 11:50:18 -08:00
.clang-format Add .clang-tidy and .clang-format files to the toplevel of the 2019-01-29 16:43:16 +00:00
.clang-tidy - Update .clang-tidy to ignore parameters of main like functions for naming violations in clang and llvm directory 2020-01-31 16:49:45 +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.