GCC — The GNU Compiler Collection

Introduction

GCC (GNU Compiler Collection) is the original open-source compiler suite started by Richard Stallman in 1987. It remains the default system compiler on most Linux distributions and supports C, C++, Fortran, Ada, Go, and D across dozens of target architectures.

What GCC Does

• Compiles C, C++, Fortran, Ada, Go, D, and Objective-C to native machine code
• Optimizes code through multiple passes including loop vectorization, inlining, and LTO
• Targets over 60 processor architectures from ARM to x86_64 to MIPS and PowerPC
• Provides the libstdc++ C++ standard library and libgfortran runtime
• Includes sanitizers, profiling instrumentation, and static analysis warnings

Architecture Overview

GCC uses a three-stage pipeline. Each language frontend parses source into the GENERIC tree representation, which is lowered to GIMPLE for high-level optimizations. GIMPLE is then converted to RTL (Register Transfer Language) for target-specific optimization and register allocation before final assembly output. Plugins can hook into any stage.

Self-Hosting & Configuration

• Install from distribution packages: apt install gcc g++ or dnf install gcc gcc-c++
• Build from source with ./configure --enable-languages=c,c++,fortran && make -j$(nproc)
• Select optimization level with -O0 through -O3, -Os for size, or -Ofast for aggressive
• Use -march=native to optimize for the current CPU microarchitecture
• Enable link-time optimization with -flto for whole-program analysis

Key Features

• Broadest architecture support of any open-source compiler (60+ targets)
• Mature C++ standards support up to C++23 and ongoing C++26 work
• Profile-guided optimization (PGO) for data-driven performance tuning
• Plugin API for custom analysis and transformation passes
• Fortran frontend (gfortran) widely used in scientific and HPC computing

Comparison with Similar Tools

• LLVM/Clang — modular design, faster compile times for C/C++; fewer legacy target backends
• MSVC — Microsoft compiler for Windows; proprietary, strongest Windows SDK integration
• Intel oneAPI (ICX) — LLVM-based with Intel-specific optimizations; commercial focus
• TCC — tiny C compiler for fast iteration; minimal optimization, C only

FAQ

Q: When should I use GCC vs Clang? A: GCC has broader platform support and is the default on most Linux distros. Clang offers better diagnostics and faster compile times. Both produce competitive runtime performance.

Q: Does GCC support cross-compilation? A: Yes. Configure a cross-compiler with --target=aarch64-linux-gnu to build for a different architecture.

Q: What is the latest stable GCC version? A: GCC follows annual major releases (e.g., GCC 14 in 2024). Check gcc.gnu.org/releases.html for the current version.

Q: Can GCC compile Rust or Swift? A: There is an experimental Rust frontend (gccrs) in progress. Swift is not supported.

Sources

• https://github.com/gcc-mirror/gcc
• https://gcc.gnu.org/onlinedocs/