contrib: Add bootstrap-go-toolchain.sh

contrib/gobuild/bootstrap-go-toolchain.sh

@@ -0,0 +1,151 @@
+#!/bin/sh
+# Build Go from source on Windows using w64devkit.
+# Bootstraps from Go 1.4 through intermediate versions up to the latest.
+#
+# Usage: ./bootstrap-go-toolchain.sh [INSTALL_DIR]
+#   INSTALL_DIR  Where to install the final Go toolchain (default: ./go)
+#
+# Prerequisites: w64devkit in PATH (provides gcc, wget, tar, patch, sh)
+#
+# The final version is patched with go-bigobj.patch located next to
+# this script before building.
+# Tarballs are verified against the SHA-256 values embedded below.
+#
+# Bootstrap chain (per https://go.dev/doc/install/source):
+#   Go 1.4  -> built with C compiler (gcc from w64devkit)
+#   Go 1.17 -> built with Go 1.4
+#   Go 1.20 -> built with Go 1.17
+#   Go 1.22 -> built with Go 1.20
+#   Go 1.24 -> built with Go 1.22
+#   Go 1.26 -> built with Go 1.24
+#
+# Go 1.N requires Go 1.M to build, where M = N-2 rounded down to even.
+
+set -e
+
+# The Windows bootstrap breaks if GOBIN is present in the environment.
+unset GOBIN
+
+# --- Version configuration (update as needed) ---
+BOOTSTRAP_VERSIONS="1.17.13 1.20.14 1.22.12 1.24.6"
+FINAL_VERSION=1.26.3
+
+# --- Paths ---
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+BUILD="$SCRIPT_DIR/build"
+DOWNLOADS="$SCRIPT_DIR/downloads"
+PATCH_FILE="$SCRIPT_DIR/go-bigobj.patch"
+INSTALL="${1:-$SCRIPT_DIR/go}"
+
+# --- URLs ---
+GO14_URL="https://github.com/golang/go/archive/refs/heads/release-branch.go1.4.tar.gz"
+GO_DL_URL="https://go.dev/dl"
+
+# --- SHA-256 sums ---
+SHA256SUMS='10273543295cf4d97df5b1ff9b1db4089099b7cada99f14cfa1dfae9be789556  go1.4-branch.tar.gz
+a1a48b23afb206f95e7bbaa9b898d965f90826f6f1d1fc0c1d784ada0cd300fd  go1.17.13.src.tar.gz
+1aef321a0e3e38b7e91d2d7eb64040666cabdcc77d383de3c9522d0d69b67f4e  go1.20.14.src.tar.gz
+012a7e1f37f362c0918c1dfa3334458ac2da1628c4b9cf4d9ca02db986e17d71  go1.22.12.src.tar.gz
+e1cb5582aab588668bc04c07de18688070f6b8c9b2aaf361f821e19bd47cfdbd  go1.24.6.src.tar.gz
+1c646875d0aa8799133184ed57cf79ff24bdefe8c8820470602a9d3d6d9192b8  go1.26.3.src.tar.gz'
+
+lookup_checksum_entry() {
+    name="$1"
+    printf '%s\n' "$SHA256SUMS" | awk -v name="$name" '$2 == name { print; found=1; exit } END { if (!found) exit 1 }'
+}
+
+verify_download() {
+    name="$1"
+    entry="$(lookup_checksum_entry "$name")" || {
+        printf 'Missing embedded checksum for %s\n' "$name" >&2
+        return 1
+    }
+
+    (
+        cd "$DOWNLOADS"
+        printf '%s\n' "$entry" | sha256sum -c
+    )
+}
+
+download() {
+    dest="$1"
+    url="$2"
+    name="$(basename "$dest")"
+
+    if [ -f "$dest" ]; then
+        if verify_download "$name" >/dev/null; then
+            printf 'Verified cached %s\n' "$name"
+            return
+        fi
+
+        printf 'Checksum mismatch for %s, re-downloading\n' "$name"
+        rm -f "$dest"
+    fi
+
+    printf "Downloading %s\n" "$name"
+    wget -O "$dest" "$url"
+    verify_download "$name"
+}
+
+echo "Go bootstrap build"
+echo "  Install to: $INSTALL"
+echo ""
+
+if [ ! -f "$PATCH_FILE" ]; then
+    printf "Missing required patch: %s\n" "$PATCH_FILE" >&2
+    exit 1
+fi
+
+mkdir -p "$BUILD" "$DOWNLOADS"
+
+# Download all source tarballs
+download "$DOWNLOADS/go1.4-branch.tar.gz" "$GO14_URL"
+for v in $BOOTSTRAP_VERSIONS $FINAL_VERSION; do
+    download "$DOWNLOADS/go${v}.src.tar.gz" "$GO_DL_URL/go${v}.src.tar.gz"
+done
+
+# Build Go 1.4 from C source
+echo ""
+echo "===== Building Go 1.4 (C bootstrap) ====="
+rm -rf "$BUILD/go1.4"
+mkdir -p "$BUILD/go1.4"
+tar xf "$DOWNLOADS/go1.4-branch.tar.gz" -C "$BUILD/go1.4" --strip-components=1
+cd "$BUILD/go1.4/src"
+CGO_ENABLED=0 cmd /c make.bat
+
+PREV="$BUILD/go1.4"
+
+# Build each intermediate version
+for v in $BOOTSTRAP_VERSIONS; do
+    echo ""
+    echo "===== Building Go $v ====="
+    rm -rf "$BUILD/go${v}"
+    mkdir -p "$BUILD/go${v}"
+    tar xf "$DOWNLOADS/go${v}.src.tar.gz" -C "$BUILD/go${v}" --strip-components=1
+    cd "$BUILD/go${v}/src"
+    CGO_ENABLED=0 GOROOT_BOOTSTRAP="$PREV" cmd /c make.bat
+    PREV="$BUILD/go${v}"
+done
+
+# Build final version with patches
+echo ""
+echo "===== Building Go $FINAL_VERSION ====="
+rm -rf "$BUILD/go${FINAL_VERSION}"
+mkdir -p "$BUILD/go${FINAL_VERSION}"
+tar xf "$DOWNLOADS/go${FINAL_VERSION}.src.tar.gz" -C "$BUILD/go${FINAL_VERSION}" --strip-components=1
+
+printf "Applying %s\n" "$(basename "$PATCH_FILE")"
+(cd "$BUILD/go${FINAL_VERSION}" && patch -p1 < "$PATCH_FILE")
+
+cd "$BUILD/go${FINAL_VERSION}/src"
+CGO_ENABLED=1 GOROOT_BOOTSTRAP="$PREV" cmd /c make.bat
+
+# Install
+echo ""
+echo "===== Installing ====="
+rm -rf "$INSTALL"
+cp -r "$BUILD/go${FINAL_VERSION}" "$INSTALL"
+
+echo ""
+echo "Go $FINAL_VERSION installed to $INSTALL"
+echo "Add $INSTALL/bin to your PATH."