#!/usr/bin/env bash
# run_sim.sh -- run a CUDA binary on the GreenEye-GPGPU-Sim TU104 scaffold.
#
# Substitutes the CUDA runtime with GPGPU-Sim's libcudart.so via
# LD_LIBRARY_PATH (the mechanism documented in the upstream README, "Step 3:
# Run"), points the simulator at the tracked TU104 scaffold config, and
# executes the binary from a dedicated run directory so simulator output does
# not pollute the source tree.
#
# Development-only tooling: it simulates; it never touches GPU hardware,
# kernel modules, mdev, or a guest.
#
# Usage:
#   ./run_sim.sh [--workdir DIR] [--build-type release|debug] <cuda-binary> [args...]
#
# Prerequisites: ./setup.sh has completed a build, and the binary was linked
# with `--cudart shared` so it resolves libcudart.so dynamically.
#
# Outputs (in the work directory, default gpgpu-sim/build/run/):
#   gpgpusim.config -> symlink to the tracked TU104 config
#   config_turing_islip.icnt -> symlink to the tracked interconnect config
#   gpgpusim_out.txt, gpgpu_inst_stats.txt, ... (upstream simulator outputs)
set -euo pipefail

HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
UPSTREAM="$HERE/upstream"
DEFAULT_CONFIG_DIR="$HERE/configs/turing-tu104-2080super"
CONFIG_NAME="gpgpusim.config"
ICNT_NAME="config_turing_islip.icnt"
BUILD_TYPE="${GPGPUSIM_BUILD_TYPE:-release}"
WORKDIR="${GPGPUSIM_RUN_DIR:-$HERE/build/run}"
CONFIG_DIR="$DEFAULT_CONFIG_DIR"

die() { echo "run_sim.sh: ERROR: $*" >&2; exit 1; }

usage() {
    cat <<'EOF'
Usage: run_sim.sh [--workdir DIR] [--build-type release|debug] \
                  [--config-dir DIR] <cuda-binary> [args...]

  --workdir DIR      directory the binary runs in (default gpgpu-sim/build/run)
  --build-type TYPE  release (default) or debug
  --config-dir DIR   config directory to use (default configs/turing-tu104-2080super)
  -h, --help         this help

The binary must be dynamically linked against libcudart (link with
"--cudart shared"); LD_LIBRARY_PATH is replaced with the GPGPU-Sim runtime
so no recompilation for the simulator is needed.
EOF
}

while [ $# -gt 0 ]; do
    case "$1" in
        --workdir)     WORKDIR="${2:-}"; shift ;;
        --build-type)  BUILD_TYPE="${2:-}"; shift ;;
        --config-dir)  CONFIG_DIR="${2:-}"; shift ;;
        -h|--help)     usage; exit 0 ;;
        --)            shift; break ;;
        -*)            usage >&2; exit 2 ;;
        *)             break ;;
    esac
    shift
done

[ $# -ge 1 ] || { usage >&2; exit 2; }
[ -n "$WORKDIR" ] || die "--workdir requires a value"
[ -n "$CONFIG_DIR" ] || die "--config-dir requires a value"
case "$BUILD_TYPE" in release|debug) ;; *) die "unknown build type '$BUILD_TYPE'" ;; esac

BIN="$1"; shift

case "$BIN" in
    */*)
        [ -e "$BIN" ] || die "binary not found: $BIN"
        BIN="$(cd "$(dirname "$BIN")" && pwd)/$(basename "$BIN")"
        ;;
    *)
        resolved="$(command -v "$BIN" || true)"
        [ -n "$resolved" ] || die "binary '$BIN' not found in PATH"
        BIN="$resolved"
        ;;
esac

[ -d "$CONFIG_DIR" ] || die "config dir not found: $CONFIG_DIR"
[ -f "$CONFIG_DIR/$CONFIG_NAME" ] || die "missing $CONFIG_DIR/$CONFIG_NAME"

LIBDIR="$(find "$UPSTREAM/lib" -maxdepth 3 -type d -name "$BUILD_TYPE" 2>/dev/null | sort | head -n 1 || true)"
[ -n "$LIBDIR" ] || die "no GPGPU-Sim runtime library dir under $UPSTREAM/lib; run ./setup.sh first"
if ! ls "$LIBDIR"/libcudart.so* >/dev/null 2>&1; then
    echo "run_sim.sh: WARNING: no libcudart.so in $LIBDIR; the binary may load the system CUDA runtime" >&2
fi

mkdir -p "$WORKDIR"
ln -sfn "$CONFIG_DIR/$CONFIG_NAME" "$WORKDIR/$CONFIG_NAME"
if [ -f "$CONFIG_DIR/$ICNT_NAME" ]; then
    ln -sfn "$CONFIG_DIR/$ICNT_NAME" "$WORKDIR/$ICNT_NAME"
fi

export GPGPUSIM_ROOT="$UPSTREAM"
export LD_LIBRARY_PATH="$LIBDIR${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
export CUDA_INSTALL_PATH="${CUDA_INSTALL_PATH:-/usr/local/cuda}"

echo "run_sim.sh: binary      : $BIN"
echo "run_sim.sh: config      : $CONFIG_DIR/$CONFIG_NAME"
echo "run_sim.sh: workdir     : $WORKDIR"
echo "run_sim.sh: runtime libs: $LIBDIR"

cd "$WORKDIR"
exec "$BIN" "$@"