scripts: add install_compiler_binaries.sh

New script to install Sierra compiler binaries (starknet-sierra-compile,
starknet-native-compile). Reads versions from .txt files, handles LLVM
env vars for native compile, and skips gracefully when LLVM 19 is missing.

Includes compiler_versions.sh helper that reads version .txt files.

Not yet called from install_cargo_tools.sh — wired up in a follow-up.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: avi-starkware

scripts/compiler_versions.sh

@@ -0,0 +1,8 @@
+#!/bin/env bash
+# Reads compiler binary versions from version files (the single source of truth).
+# Source this script to get $SIERRA_COMPILE_VERSION and $NATIVE_COMPILE_VERSION.
+
+REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || echo "$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)")"
+
+SIERRA_COMPILE_VERSION=$(cat "$REPO_ROOT/crates/apollo_infra_utils/src/cairo_compiler_version.txt")
+NATIVE_COMPILE_VERSION=$(cat "$REPO_ROOT/crates/apollo_compile_to_native/src/native_compiler_version.txt")

scripts/install_compiler_binaries.sh

@@ -0,0 +1,56 @@
+#!/bin/env bash
+# Installs Sierra compiler binaries (starknet-sierra-compile, starknet-native-compile).
+# Versions are read from plain text files that are the single source of truth for both
+# Rust code and this script.
+#
+# Called from install_cargo_tools.sh. Can also be run standalone after LLVM 19 is installed.
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]:-$0}")" && pwd)"
+
+# Source version files and shared utilities.
+source "${SCRIPT_DIR}/compiler_versions.sh"
+if [ -f "${SCRIPT_DIR}/apt_utils.sh" ]; then
+    source "${SCRIPT_DIR}/apt_utils.sh"
+elif [ -f "./apt_utils.sh" ]; then
+    source "./apt_utils.sh"
+fi
+
+# Install a compiler binary only if needed (not installed or different version).
+function install_compiler_if_needed() {
+    local binary_name=$1
+    local version=$2
+    local current
+    current=$($binary_name --version 2>/dev/null | grep -oP '\d+\.\d+\.\d+(-[a-zA-Z0-9.]+)?' | head -1) || true
+    if [ "$current" = "$version" ]; then
+        log_step "install_build_tools" "$binary_name $version already installed, skipping"
+    else
+        if [ -n "$current" ]; then
+            log_step "install_build_tools" "Replacing $binary_name $current with $version..."
+        else
+            log_step "install_build_tools" "Installing $binary_name $version..."
+        fi
+        cargo install "$binary_name" --version "$version" --force
+        log_step "install_build_tools" "$binary_name installed successfully"
+    fi
+}
+
+# LLVM/MLIR env vars are normally set by .cargo/config.toml, but cargo install runs
+# outside the workspace so they must be set explicitly.
+if [ -f "$REPO_ROOT/.cargo/config.toml" ]; then
+    eval "$(grep -E '(LLVM_SYS|MLIR_SYS|TABLEGEN)' "$REPO_ROOT/.cargo/config.toml" | sed 's/ = /=/' | tr -d '"')"
+    export LLVM_SYS_191_PREFIX MLIR_SYS_190_PREFIX TABLEGEN_190_PREFIX
+fi
+
+# RUSTC_WRAPPER="" avoids sccache circular dependency during installation.
+RUSTC_WRAPPER="" install_compiler_if_needed "starknet-sierra-compile" "$SIERRA_COMPILE_VERSION"
+
+# starknet-native-compile requires LLVM 19. If LLVM is not installed, print instructions
+# instead of failing with a cryptic tblgen build error.
+if command -v llvm-config-19 &>/dev/null; then
+    RUSTC_WRAPPER="" install_compiler_if_needed "starknet-native-compile" "$NATIVE_COMPILE_VERSION"
+else
+    log_step "install_build_tools" "Skipping starknet-native-compile (LLVM 19 not found)."
+    log_step "install_build_tools" "To install it: run 'scripts/dependencies.sh' first, then re-run this script."
+fi