Toolchain: Move GDB build to a separate script

Target GDB is only used for debugging the kernel, which is not relevant
to most people. Starting with 924758c6f8bcf, GDB would always be built
as part of the toolchain if the user didn't have it installed. This is
unnecessary.

This commit adds a separate script for building GDB, which the user
needs to explicitly invoke. A message is added to Meta/debug-kernel.sh
which alerts the user to this fact.

3 files changed, 135 insertions, 98 deletions

diff --git a/Meta/debug-kernel.sh b/Meta/debug-kernel.sh
index 04afa992b0..4e902155b6 100755
--- a/Meta/debug-kernel.sh
+++ b/Meta/debug-kernel.sh
@@ -9,7 +9,9 @@ fi
 # Set this environment variable to override the default debugger.
 #
 if [ -z "$SERENITY_KERNEL_DEBUGGER" ]; then
-    # Prepend the toolchain bin directory so we pick up GDB from there
+    # Prepend the toolchain's GDB bin directory so we pick up GDB from there
+    PATH="$SCRIPT_DIR/../Toolchain/Local/$SERENITY_ARCH-gdb/bin:$PATH"
+    # GDB used to be installed directly inside the toolchain bin directory
     PATH="$SCRIPT_DIR/../Toolchain/Local/$SERENITY_ARCH/bin:$PATH"
 
     if command -v "$SERENITY_ARCH-pc-serenity-gdb" >/dev/null; then
@@ -20,6 +22,9 @@ if [ -z "$SERENITY_KERNEL_DEBUGGER" ]; then
         SERENITY_KERNEL_DEBUGGER="gdb"
     else
         echo "Error: No suitable GDB installation found." >&2
+        echo "Please install $SERENITY_ARCH-elf-gdb or build it with Toolchain/BuildGDB.sh $SERENITY_ARCH" >&2
+        # Prevent tmux from dying instantly by waiting for user input
+        read -rp "Press Enter to exit"
         exit 1
     fi
 fi
diff --git a/Toolchain/BuildGDB.sh b/Toolchain/BuildGDB.sh
new file mode 100755
index 0000000000..75d16d9fd2
--- /dev/null
+++ b/Toolchain/BuildGDB.sh
@@ -0,0 +1,129 @@
+#!/usr/bin/env bash
+set -e
+
+GDB_VERSION="13.1"
+GDB_MD5SUM="4aaad768ff2585464173c091947287ec"
+GDB_NAME="gdb-$GDB_VERSION"
+GDB_PKG="${GDB_NAME}.tar.xz"
+GDB_BASE_URL="https://ftp.gnu.org/gnu/gdb"
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+ARCH=${1:-"x86_64"}
+TARGET="$ARCH-pc-serenity"
+PREFIX="$DIR/Local/$ARCH-gdb"
+
+echo "Building GDB $GDB_VERSION for $TARGET"
+
+MD5SUM="md5sum"
+NPROC="nproc"
+
+SYSTEM_NAME="$(uname -s)"
+
+if [ "$SYSTEM_NAME" = "OpenBSD" ]; then
+    MD5SUM="md5 -q"
+    NPROC="sysctl -n hw.ncpuonline"
+    export CC=egcc
+    export CXX=eg++
+    export with_gmp=/usr/local
+    export LDFLAGS=-Wl,-z,notext
+elif [ "$SYSTEM_NAME" = "FreeBSD" ]; then
+    MD5SUM="md5 -q"
+    NPROC="sysctl -n hw.ncpu"
+    export with_gmp=/usr/local
+    export with_mpfr=/usr/local
+elif [ "$SYSTEM_NAME" = "Darwin" ]; then
+    MD5SUM="md5 -q"
+    NPROC="sysctl -n hw.ncpu"
+fi
+
+if [ -z "$MAKEJOBS" ]; then
+    MAKEJOBS=$($NPROC)
+fi
+
+buildstep() {
+    NAME=$1
+    shift
+    "$@" 2>&1 | sed $'s|^|\x1b[34m['"${NAME}"$']\x1b[39m |'
+}
+
+missing_lib() {
+    buildstep dependencies echo "Please make sure to install the $lib library and headers." >&2
+    exit 1
+}
+
+config_args=()
+for lib in gmp isl mpfr mpc; do
+    buildstep dependencies echo "Checking whether the $lib library and headers are available..."
+    if [ "$SYSTEM_NAME" = "Darwin" ]; then
+        [ "$lib" = "mpc" ] && formula_name="libmpc" || formula_name="$lib"
+        config_args+=("--with-$lib=$(brew --prefix --installed "$formula_name")") || missing_lib $lib
+    else
+        if ! ${CC:-cc} -I /usr/local/include -L /usr/local/lib -l$lib -o /dev/null -xc - >/dev/null <<PROGRAM
+#include <$lib.h>
+int main() {}
+PROGRAM
+              then
+                  missing_lib $lib
+              fi
+    fi
+done
+
+if [ "$SYSTEM_NAME" = "Darwin" ]; then
+    config_args+=("--with-libgmp-prefix=$(brew --prefix gmp)")
+fi
+
+mkdir -p "$DIR/Tarballs"
+
+pushd "$DIR/Tarballs"
+    md5=""
+    if [ -e "$GDB_PKG" ]; then
+        md5="$($MD5SUM "$GDB_PKG" | cut -f1 -d' ')"
+    fi
+    if [ "$md5" != "$GDB_MD5SUM" ]; then
+        curl -C - -O "$GDB_BASE_URL/$GDB_PKG"
+    else
+        echo "Skipped downloading $GDB_PKG"
+    fi
+
+    md5="$($MD5SUM "$GDB_PKG" | cut -f1 -d' ')"
+    echo "gdb md5='$md5'"
+    if  [ "$md5" != "$GDB_MD5SUM" ] ; then
+        echo "gdb md5 sum mismatching, please run script again."
+        rm -f "$GDB_PKG"
+        exit 1
+    fi
+
+    # If the source directory exists, re-extract it again in case the patches have changed.
+    if [ -d ${GDB_NAME} ]; then
+        rm -rf "${GDB_NAME}"
+        rm -rf "$DIR/Build/$ARCH-gdb"
+    fi
+    echo "Extracting gdb..."
+    tar -xJf "$GDB_PKG"
+
+    pushd "$GDB_NAME"
+        for patch in "${DIR}"/Patches/gdb/*.patch; do
+            patch -p1 < "${patch}" > /dev/null
+        done
+    popd
+popd
+
+mkdir -p "$DIR/Build"
+
+rm -rf "$DIR/Build/$ARCH-gdb"
+mkdir "$DIR/Build/$ARCH-gdb"
+
+pushd "$DIR/Build/$ARCH-gdb"
+    unset PKG_CONFIG_LIBDIR # Just in case
+
+    buildstep "gdb/configure" "$DIR"/Tarballs/$GDB_NAME/configure --prefix="$PREFIX" \
+                                                                  --target="$TARGET" \
+                                                                  --disable-werror \
+                                                                  --disable-nls \
+                                                                  --with-python \
+                                                                  "${config_args[@]}" || exit 1
+
+    buildstep "gdb/build" make MAKEINFO=true -j "$MAKEJOBS" || exit 1
+    buildstep "gdb/install" make MAKEINFO=true install || exit 1
+popd
diff --git a/Toolchain/BuildIt.sh b/Toolchain/BuildIt.sh
index 777f2685e2..69c2c5af2d 100755
--- a/Toolchain/BuildIt.sh
+++ b/Toolchain/BuildIt.sh
@@ -80,12 +80,6 @@ BINUTILS_NAME="binutils-$BINUTILS_VERSION"
 BINUTILS_PKG="${BINUTILS_NAME}.tar.gz"
 BINUTILS_BASE_URL="https://ftp.gnu.org/gnu/binutils"
 
-GDB_VERSION="13.1"
-GDB_MD5SUM="92b70971e81a450f6b3e1cf568671cfa"
-GDB_NAME="gdb-$GDB_VERSION"
-GDB_PKG="${GDB_NAME}.tar.gz"
-GDB_BASE_URL="https://ftp.gnu.org/gnu/gdb"
-
 # Note: If you bump the gcc version, you also have to update the matching
 #       GCC_VERSION variable in the project's root CMakeLists.txt
 GCC_VERSION="12.2.0"
@@ -100,21 +94,6 @@ buildstep() {
     "$@" 2>&1 | sed $'s|^|\x1b[34m['"${NAME}"$']\x1b[39m |'
 }
 
-has_gdb() {
-    ARCH=$1
-    ARCH_DASH="${ARCH//_/-}"
-    if command -v gdb >/dev/null && gdb -ex 'set architecture' -ex 'quit' 2>&1 | grep "$ARCH_DASH"; then
-        return 0
-    else
-        command -v "$ARCH"-elf-gdb >/dev/null
-    fi
-}
-
-NEEDS_GDB=1
-if has_gdb "$ARCH"; then
-    NEEDS_GDB=0
-fi
-
 # === DEPENDENCIES ===
 buildstep dependencies echo "Checking whether 'make' is available..."
 if ! command -v ${MAKE:-make} >/dev/null; then
@@ -197,22 +176,6 @@ popd
 # === DOWNLOAD AND PATCH ===
 
 pushd "$DIR/Tarballs"
-    # Build gdb for cross-debugging support
-    if [ $NEEDS_GDB -eq 1 ]; then
-        echo "GDB not found for $ARCH. Will build it from source."
-        md5=""
-        if [ -e "$GDB_PKG" ]; then
-            md5="$($MD5SUM $GDB_PKG | cut -f1 -d' ')"
-            echo "gdb md5='$md5'"
-        fi
-        if [ "$md5" != ${GDB_MD5SUM} ] ; then
-            rm -f $GDB_PKG
-            curl -LO "$GDB_BASE_URL/$GDB_PKG"
-        else
-            echo "Skipped downloading gdb"
-        fi
-    fi
-
     md5=""
     if [ -e "$BINUTILS_PKG" ]; then
         md5="$($MD5SUM $BINUTILS_PKG | cut -f1 -d' ')"
@@ -237,29 +200,6 @@ pushd "$DIR/Tarballs"
         echo "Skipped downloading gcc"
     fi
 
-    if [ $NEEDS_GDB -eq 1 ]; then
-        if [ -d ${GDB_NAME} ]; then
-            rm -rf "${GDB_NAME}"
-            rm -rf "$DIR/Build/$ARCH/$GDB_NAME"
-        fi
-        echo "Extracting GDB..."
-        tar -xzf ${GDB_PKG}
-
-        pushd ${GDB_NAME}
-            if [ "$git_patch" = "1" ]; then
-                git init > /dev/null
-                git add . > /dev/null
-                git commit -am "BASE" > /dev/null
-                git am "${DIR}"/Patches/gdb/*.patch > /dev/null
-            else
-                for patch in "${DIR}"/Patches/gdb/*.patch; do
-                    patch -p1 < "${patch}" > /dev/null
-                done
-            fi
-            $MD5SUM "$DIR"/Patches/gdb/*.patch > .patch.applied
-        popd
-    fi
-
     patch_md5="$(${MD5SUM} "${DIR}"/Patches/binutils/*.patch)"
 
     if [ ! -d "${BINUTILS_NAME}" ] || [ "$(cat ${BINUTILS_NAME}/.patch.applied)" != "${patch_md5}" ]; then
@@ -335,43 +275,6 @@ mkdir -p "$DIR/Build/$ARCH"
 pushd "$DIR/Build/$ARCH"
     unset PKG_CONFIG_LIBDIR # Just in case
 
-    if [ $NEEDS_GDB -eq 1 ]; then
-        rm -rf gdb
-        mkdir -p gdb
-
-        pushd gdb
-            echo "XXX configure gdb"
-
-
-            if [ "$SYSTEM_NAME" = "Darwin" ]; then
-                buildstep "gdb/configure" "$DIR"/Tarballs/$GDB_NAME/configure --prefix="$PREFIX" \
-                                                        --target="$TARGET" \
-                                                        --with-sysroot="$SYSROOT" \
-                                                        --enable-shared \
-                                                        --disable-werror \
-                                                        --with-libgmp-prefix="$(brew --prefix gmp)" \
-                                                        --with-gmp="$(brew --prefix gmp)" \
-                                                        --with-isl="$(brew --prefix isl)" \
-                                                        --with-mpc="$(brew --prefix libmpc)" \
-                                                        --with-mpfr="$(brew --prefix mpfr)" \
-                                                        --disable-nls \
-                                                        ${TRY_USE_LOCAL_TOOLCHAIN:+"--quiet"} || exit 1
-            else
-                buildstep "gdb/configure" "$DIR"/Tarballs/$GDB_NAME/configure --prefix="$PREFIX" \
-                                                        --target="$TARGET" \
-                                                        --with-sysroot="$SYSROOT" \
-                                                        --enable-shared \
-                                                        --disable-werror \
-                                                        --disable-nls \
-                                                        ${TRY_USE_LOCAL_TOOLCHAIN:+"--quiet"} || exit 1
-            fi
-
-            echo "XXX build gdb"
-            buildstep "gdb/build" "$MAKE" MAKEINFO=true -j "$MAKEJOBS" || exit 1
-            buildstep "gdb/install" "$MAKE" MAKEINFO=true install || exit 1
-        popd
-    fi
-
     rm -rf binutils
     mkdir -p binutils