foxhunt/setup_lld.sh

#!/bin/bash
set -e

echo "=========================================="
echo "LLD Linker Setup Script for Foxhunt"
echo "=========================================="
echo ""

# Check if running with sudo
if [ "$EUID" -eq 0 ]; then 
    echo "✓ Running with sudo privileges"
else
    echo "⚠️  This script requires sudo privileges"
    echo "   Please run: sudo bash $0"
    exit 1
fi

# Install lld
echo "Step 1: Installing lld..."
apt-get update -qq
apt-get install -y lld

echo ""
echo "Step 2: Verifying installation..."
if command -v ld.lld &> /dev/null; then
    echo "✓ LLD installed successfully"
    ld.lld --version
else
    echo "✗ LLD installation failed"
    exit 1
fi

# Update .cargo/config.toml
echo ""
echo "Step 3: Updating .cargo/config.toml..."
FOXHUNT_DIR="/home/jgrusewski/Work/foxhunt"
CONFIG_FILE="$FOXHUNT_DIR/.cargo/config.toml"

if [ ! -f "$CONFIG_FILE" ]; then
    echo "✗ Config file not found: $CONFIG_FILE"
    exit 1
fi

# Backup original
cp "$CONFIG_FILE" "$CONFIG_FILE.backup.$(date +%Y%m%d_%H%M%S)"
echo "✓ Backup created: $CONFIG_FILE.backup.*"

# Apply changes
cat > "$CONFIG_FILE" << 'CONFIGEOF'
[env]
# SQLx offline mode - use cached query metadata from .sqlx/ directory
# Generated with: cargo sqlx prepare --workspace
SQLX_OFFLINE = "true"

[build]
rustflags = [
    "-D", "unsafe_op_in_unsafe_fn",
    "-D", "clippy::undocumented_unsafe_blocks",
    "-W", "rust_2024_idioms",
    "-C", "force-frame-pointers=yes",
    # REMOVED: "-C", "stack-protector=strong",  # Not compatible with coverage tools
    "-C", "relocation-model=pic",
]

[target.x86_64-unknown-linux-gnu]
linker = "clang"
rustflags = [
    "-C", "link-arg=-Wl,-z,relro,-z,now",
    "-C", "link-arg=-Wl,--as-needed",
    "-C", "link-arg=-fuse-ld=lld",  # LLD linker for faster linking (5-10x improvement)
    # CRITICAL HFT PERFORMANCE FLAGS - FIXES SIMD 10,000x REGRESSION
    "-C", "target-cpu=native",
    "-C", "target-feature=+avx2,+fma,+bmi2",
    "-C", "opt-level=3",
    "-C", "codegen-units=1",
]

# Profile-specific optimizations for maximum SIMD performance
[profile.release]
opt-level = 3
lto = "fat"
codegen-units = 1
panic = "abort"
strip = false
debug = false
overflow-checks = false

# Benchmarking profile with SIMD optimizations
[profile.bench]
inherits = "release"
debug = false

# HFT-specific profile for production with aggressive SIMD optimization
[profile.hft]
inherits = "release"
opt-level = 3
lto = "fat"
codegen-units = 1
panic = "abort"
strip = false
overflow-checks = false
CONFIGEOF

echo "✓ Configuration updated"

# Test compilation
echo ""
echo "Step 4: Testing compilation..."
cd "$FOXHUNT_DIR"
sudo -u jgrusewski bash << 'TESTEOF'
cd /home/jgrusewski/Work/foxhunt
echo "Running: cargo check --workspace"
cargo check --workspace 2>&1 | head -20
TESTEOF

if [ $? -eq 0 ]; then
    echo "✓ Compilation test passed"
else
    echo "⚠️  Compilation test encountered issues (this may be normal)"
fi

echo ""
echo "=========================================="
echo "✓ LLD Setup Complete!"
echo "=========================================="
echo ""
echo "Next steps:"
echo "1. Run a clean build: cargo clean && time cargo build --release"
echo "2. Compare build times with previous builds"
echo "3. Expected improvement: 40-60% faster linking"
echo ""
echo "Backup location: $CONFIG_FILE.backup.*"