2b47497f6e
Restructured the Getting Started guide into a numbered step-by-step path for easier readability. Added a Hello World verification step to confirm build integrity after build completion. Additionally, updated build_concepts.rst and the Getting Started guide to clarify that Overlay Mode is intended for augmenting the system's C library rather than incremental adoption.
100 lines
2.6 KiB
ReStructuredText
100 lines
2.6 KiB
ReStructuredText
.. _getting_started:
|
|
|
|
===============
|
|
Getting Started
|
|
===============
|
|
|
|
This guide provides a single, robust path for new users and contributors to
|
|
build, test, and verify LLVM-libc. We use the **runtimes build** (see
|
|
:ref:`build_concepts` for more information) because it is faster and sufficient
|
|
for most development tasks.
|
|
|
|
1. Install Dependencies
|
|
=======================
|
|
|
|
To build LLVM-libc, you will need a recent version of Clang (v15+) and basic
|
|
build tools. On a Debian/Ubuntu-based system, you can install these using
|
|
``apt-get``:
|
|
|
|
.. code-block:: sh
|
|
|
|
sudo apt-get update
|
|
sudo apt-get install git cmake ninja-build clang gcc-multilib
|
|
|
|
2. Clone and Configure
|
|
======================
|
|
|
|
The following command clones the complete LLVM project and configures the
|
|
build for LLVM-libc. We include ``compiler-rt`` to enable the Scudo memory
|
|
allocator.
|
|
|
|
.. code-block:: sh
|
|
|
|
git clone --depth=1 https://github.com/llvm/llvm-project.git
|
|
cd llvm-project
|
|
cmake -G Ninja -S runtimes -B build \
|
|
-DLLVM_ENABLE_RUNTIMES="libc;compiler-rt" \
|
|
-DLLVM_LIBC_FULL_BUILD=ON \
|
|
-DCMAKE_BUILD_TYPE=Debug \
|
|
-DCMAKE_C_COMPILER=clang \
|
|
-DCMAKE_CXX_COMPILER=clang++ \
|
|
-DLLVM_LIBC_INCLUDE_SCUDO=ON \
|
|
-DCOMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC=ON \
|
|
-DCOMPILER_RT_BUILD_GWP_ASAN=OFF \
|
|
-DCOMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED=OFF \
|
|
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON
|
|
|
|
3. Build and Test
|
|
=================
|
|
|
|
After configuring, you can build the library, the math library (libm), and
|
|
run all unit tests:
|
|
|
|
.. code-block:: sh
|
|
|
|
ninja -C build libc libm check-libc
|
|
|
|
To run a specific test, such as ``isalpha`` in ``ctype.h``:
|
|
|
|
.. code-block:: sh
|
|
|
|
ninja -C build libc.test.src.ctype.isalpha_test.__unit__
|
|
|
|
4. Verify with Hello World
|
|
==========================
|
|
|
|
To verify your build, create a simple ``hello.c`` file:
|
|
|
|
.. code-block:: c
|
|
|
|
#include <stdio.h>
|
|
|
|
int main() {
|
|
printf("Hello world from LLVM-libc!\n");
|
|
return 0;
|
|
}
|
|
|
|
Compile it using the build artifacts:
|
|
|
|
.. code-block:: sh
|
|
|
|
clang -nostdinc -nostdlib hello.c -o hello \
|
|
-I build/libc/include \
|
|
-I $(clang -print-resource-dir)/include \
|
|
build/libc/startup/linux/crt1.o \
|
|
build/libc/lib/libc.a \
|
|
build/libc/lib/libm.a
|
|
|
|
Finally, run the executable:
|
|
|
|
.. code-block:: sh
|
|
|
|
./hello
|
|
# Output: Hello world from LLVM-libc!
|
|
|
|
This setup builds LLVM-libc as a standalone library using the
|
|
recommended set of flags. From here, you can visit :ref:`full_host_build`
|
|
for advanced sysroot setup, :ref:`overlay_mode` to learn about using
|
|
LLVM-libc to augment your system's C library, or :ref:`build_concepts`
|
|
to understand other build scenarios.
|