#!/bin/bash
# ============================================================================
# DarkForge Linux — Phase 0, Chapter 6: GCC Pass 2
# ============================================================================
# Purpose:  Rebuild GCC with the temporary toolchain. This produces a
#           compiler that runs on the target and generates code for the target.
#           Unlike Pass 1, this includes libstdc++, threading, and shared libs.
#           Hardware-specific flags (-march=znver5) are STILL not applied here;
#           they come when we build the final native GCC in the chroot.
# Inputs:   ${LFS}/sources/gcc-15.2.0.tar.xz + mpfr, gmp, mpc
# Outputs:  Full GCC in ${LFS}/usr/
# Assumes:  All Chapter 5 + Chapter 6 packages (006-021) complete
# Ref:      LFS 13.0 §6.18
# ============================================================================

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

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

echo "=== Building ${PACKAGE}-${VERSION} (Pass 2) ==="

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 (same as Pass 1)
case $(uname -m) in
    x86_64)
        sed -e '/m64=/s/lib64/lib/' -i.orig gcc/config/i386/t-linux64
        ;;
esac

# Override the default build rule for libgcc and libstdc++ headers
# to use our target-specific header directory
sed '/thread_header =/s/@.*@/gthr-posix.h/' \
    -i libgcc/Makefile.in libstdc++-v3/include/Makefile.in

mkdir -v build
cd build

# Configure GCC Pass 2
# Key differences from Pass 1:
# --with-build-sysroot=$LFS: use target sysroot during build
# --enable-default-pie/ssp: security hardening
# --disable-bootstrap: skip the 3-stage bootstrap (not building natively yet)
../configure \
    --build="$(../config.guess)" \
    --host="${LFS_TGT}" \
    --target="${LFS_TGT}" \
    LDFLAGS_FOR_TARGET=-L"${PWD}/${LFS_TGT}/libgcc" \
    --prefix=/usr \
    --with-build-sysroot="${LFS}" \
    --enable-default-pie \
    --enable-default-ssp \
    --disable-nls \
    --disable-multilib \
    --disable-libatomic \
    --disable-libgomp \
    --disable-libquadmath \
    --disable-libsanitizer \
    --disable-libssp \
    --disable-libvtv \
    --enable-languages=c,c++

make
make DESTDIR="${LFS}" install

# Create cc symlink (many build systems expect 'cc' to exist)
ln -sfv gcc "${LFS}/usr/bin/cc"

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

echo "=== ${PACKAGE}-${VERSION} Pass 2 complete ==="
echo ""
echo ">>> Cross-compilation phase (Chapters 5+6) COMPLETE."
echo ">>> Next: Enter chroot environment (Chapter 7 scripts)."