#!/bin/bash
# ============================================================================
# DarkForge Linux — Phase 0, Chapter 5: GCC Pass 1
# ============================================================================
# Purpose:  Build the cross-compiler (GCC) as the second component of the
#           cross-toolchain. This produces a C/C++ compiler that runs on the
#           host but generates code for the target (x86_64-darkforge-linux-gnu).
#           No hardware-specific flags (-march=znver5) yet — those come later
#           when we have a native compiler.
# Inputs:   ${LFS}/sources/gcc-15.2.0.tar.xz, mpfr, gmp, mpc tarballs
# Outputs:  Cross-GCC installed to ${LFS}/tools/
# Assumes:  Binutils Pass 1 complete, running as 'lfs' user
# Ref:      LFS 13.0 §5.3
# ============================================================================

set -euo pipefail
source "${LFS}/sources/darkforge-env.sh"

PACKAGE="gcc"
VERSION="15.2.0"
SRCDIR="${LFS}/sources"

echo "=== Building ${PACKAGE}-${VERSION} (Cross-Toolchain Pass 1) ==="

cd "${SRCDIR}"
tar -xf "${PACKAGE}-${VERSION}.tar.xz"
cd "${PACKAGE}-${VERSION}"

# Extract and link GCC's arithmetic library dependencies
tar -xf ../mpfr-4.2.2.tar.xz
mv -v mpfr-4.2.2 mpfr
tar -xf ../gmp-6.3.0.tar.xz
mv -v gmp-6.3.0 gmp
tar -xf ../mpc-1.3.1.tar.gz
mv -v mpc-1.3.1 mpc

# Fix lib64 directory naming on x86_64
# GCC defaults to installing 64-bit libraries in lib64, but LFS/DarkForge
# uses a unified /usr/lib directory. This sed changes the default.
case $(uname -m) in
    x86_64)
        sed -e '/m64=/s/lib64/lib/' -i.orig gcc/config/i386/t-linux64
        ;;
esac

mkdir -v build
cd build

# Configure cross-compiler
# --target=$LFS_TGT: cross-compile for our target
# --with-glibc-version=2.43: tell GCC which glibc version to expect
# --with-newlib: inhibit building libc-dependent code (no libc yet)
# --without-headers: don't look for system headers yet
# --enable-default-pie: position-independent executables by default (security)
# --enable-default-ssp: stack smashing protection by default (security)
# --disable-shared: static link GCC internal libraries
# --disable-multilib: no 32-bit support in the cross-compiler
#   (multilib will be addressed later for Steam/Wine compatibility)
# --disable-threads: no threading support yet (no glibc/pthreads)
# --disable-lib*: disable libraries that aren't needed at this stage
# --enable-languages=c,c++: only C and C++ compilers needed
../configure \
    --target="${LFS_TGT}" \
    --prefix="${LFS}/tools" \
    --with-glibc-version=2.43 \
    --with-sysroot="${LFS}" \
    --with-newlib \
    --without-headers \
    --enable-default-pie \
    --enable-default-ssp \
    --disable-nls \
    --disable-shared \
    --disable-multilib \
    --disable-threads \
    --disable-libatomic \
    --disable-libgomp \
    --disable-libquadmath \
    --disable-libssp \
    --disable-libvtv \
    --disable-libstdcxx \
    --enable-languages=c,c++

make
make install

# Create the full version of the internal limits.h header
# GCC needs this to properly handle system limits.h
cd ..
cat gcc/limitx.h gcc/glimits.h gcc/limity.h > \
    "$(dirname "$("${LFS_TGT}-gcc" -print-libgcc-file-name)")/include/limits.h"

# Cleanup
cd "${SRCDIR}"
rm -rf "${PACKAGE}-${VERSION}"

echo "=== ${PACKAGE}-${VERSION} Pass 1 complete ==="