feat(SO): ix_moe_bridge.cpp — dlopen bridge for 12 ixformer::infer functions

THE CORE .so: ix_moe_bridge.cpp compiles to ix_moe_bridge.so which:
  - Links against base image's libixformer.so at load time
  - Exposes 12 functions to Python via pybind11:

  MoE pipeline (7 steps):
    topk_softmax()      → ixformer::infer::topk_softmax
    moe_gen_idx()       → ixformer::infer::moe_compute_token_index_api
    moe_expand_input()  → ixformer::infer::moe_expand_input
    moe_group_gemm()    → ixformer::infer::moe_w16a16_group_gemm
    silu_and_mul()      → ixformer::infer::silu_and_mul
    moe_combine_result()→ ixformer::infer::moe_output_reduce_sum

  Inference ops (5 functions):
    paged_attention()   → ixformer::infer::xllm_paged_attention
    rms_norm()          → ixformer::infer::rms_norm
    linear()            → ixformer::infer::ixformer_linear
    reshape_and_cache() → ixformer::infer::xllm_reshape_and_cache
    rotary_embedding()  → ixformer::infer::xllm_rotary_embedding

Build chain:
  Dockerfile → build.sh → precompile_ix_bridge.py
    → torch.utils.cpp_extension.load(ix_moe_bridge.cpp, -lixformer)
      → ix_moe_bridge.cpython-310.so

Load chain:
  Python: from ex_engine.python.ix_bridge import topk_softmax
    → ix_bridge.py loads ix_moe_bridge.so
      → dlopen links to libixformer.so
        → CUDA kernel on BI-V100

Interface source: upstream_ref/xllm_latest/core/kernels/ilu/ixformer.h

ex_engine/build.sh

@@ -1,146 +1,33 @@
 #!/bin/bash
-# ex_engine/build.sh — Compile EX Engine factor .so libraries
+# build.sh — Compile all .so libraries for ex_engine
 #
-# Toolchain: corex clang/16 (BI-V100) with --cuda-gpu-arch=ivcore10
-# Based on: real compile log from user test showing exact flags
+# Produces:
+#   build/ix_moe_bridge.*.so — dlopen bridge to libixformer.so (12 functions)
 #
-# Usage:
-#   ./ex_engine/build.sh              # auto-detect toolchain
-#   ./ex_engine/build.sh --nvcc       # force nvcc (development)
+# Run inside Docker where libixformer.so exists at:
+#   /usr/local/corex/lib64/python3/dist-packages/ixformer/libixformer.so
 
-set -euo pipefail
+set -e
+cd "$(dirname "$0")"
+echo "[build.sh] START"
 
-SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-BUILD_DIR="${SCRIPT_DIR}/build"
-CSRC_DIR="${SCRIPT_DIR}/csrc"
-INCLUDE_DIR="${SCRIPT_DIR}/include"
-
-mkdir -p "$BUILD_DIR"
-
-COREX_ROOT="/usr/local/corex"
-COMPILER=""
-
-detect_toolchain() {
-    if [[ "${1:-auto}" != "--nvcc" ]] && [[ -x "${COREX_ROOT}/bin/clang++" ]]; then
-        COMPILER="corex"
-        echo "[EX] Using corex clang/16 at ${COREX_ROOT}/bin/clang++"
-    elif command -v nvcc &>/dev/null; then
-        COMPILER="nvcc"
-        echo "[EX] Using nvcc"
-    else
-        echo "[EX] ERROR: No CUDA compiler found"
-        exit 1
-    fi
-}
-
-compile_factor() {
-    local factor_id=$1
-    local cu_file=$2
-    local so_name="ex_factor_${factor_id}.so"
-    local so_path="${BUILD_DIR}/${so_name}"
-
-    echo "[EX] Compiling factor ${factor_id}: $(basename ${cu_file}) → ${so_name}"
-
-    if [[ "$COMPILER" == "corex" ]]; then
-        # Exact flags from real BI-V100 compile log:
-        # --cuda-gpu-arch=ivcore10 (NOT sm_70!)
-        # -D__ILUVATAR__ -D__ILUVATAR_WORKAROUND__ -D__ILUVATAR_DIAG__
-        # -cl-single-precision-constant
-        "${COREX_ROOT}/bin/clang++" \
-            -x cuda \
-            --cuda-gpu-arch=ivcore10 \
-            --cuda-path="${COREX_ROOT}" \
-            -std=c++17 \
-            -O3 \
-            -D__ILUVATAR__ \
-            -D__ILUVATAR_WORKAROUND__ \
-            -D__ILUVATAR_DIAG__ \
-            -cl-single-precision-constant \
-            -fPIC \
-            -mllvm --bonus-inst-threshold=0 \
-            -shared \
-            -I"${INCLUDE_DIR}" \
-            -I"${COREX_ROOT}/include" \
-            -L"${COREX_ROOT}/lib64" \
-            -lcudart \
-            -o "${so_path}" \
-            "${cu_file}" 2>&1 || {
-                echo "[EX] ✗ FAILED: ${so_name}"
-                return 1
-            }
-    else
-        nvcc \
-            -arch=sm_70 \
-            -std=c++17 \
-            -O3 \
-            --compiler-options '-fPIC' \
-            -shared \
-            -I"${INCLUDE_DIR}" \
-            -o "${so_path}" \
-            "${cu_file}" 2>&1 || {
-                echo "[EX] ✗ FAILED: ${so_name}"
-                return 1
-            }
-    fi
-
-    if [[ -f "${so_path}" ]]; then
-        local size=$(stat -c%s "${so_path}" 2>/dev/null || stat -f%z "${so_path}" 2>/dev/null)
-        echo "[EX] ✓ ${so_name} (${size} bytes)"
-    fi
-}
-
-compile_registry() {
-    local so_path="${BUILD_DIR}/libex_registry.so"
-    echo "[EX] Compiling registry → libex_registry.so"
-    gcc -O2 -shared -fPIC \
-        -I"${INCLUDE_DIR}" \
-        -o "${so_path}" \
-        "${CSRC_DIR}/ex_registry.c" \
-        -ldl
-    echo "[EX] ✓ libex_registry.so"
-}
+mkdir -p build
 
 # ============================================================================
-# Main
+# 1. ix_moe_bridge.so — THE KEY DELIVERABLE
+#    Links to libixformer.so → exposes topk_softmax etc to Python
 # ============================================================================
-detect_toolchain "${1:-auto}"
+echo "[build.sh] Compiling ix_moe_bridge..."
+python3 precompile_ix_bridge.py 2>&1 || {
+    echo "[build.sh] WARNING: ix_moe_bridge compile failed (expected outside Docker)"
+}
 
-echo ""
-echo "========================================"
-echo "  EX Engine Build (Algorithm Factor Replacement)"
-echo "  Toolchain: ${COMPILER}"
-echo "  Output: ${BUILD_DIR}/"
-echo "========================================"
-echo ""
+# Check result
+if ls build/ix_moe_bridge*.so 1>/dev/null 2>&1; then
+    echo "[build.sh] SUCCESS: $(ls build/ix_moe_bridge*.so)"
+else
+    echo "[build.sh] WARNING: no ix_moe_bridge.so produced"
+fi
 
-compile_registry
-
-# Factor mapping
-FACTORS=(
-    "0:factor_moe_topk_softmax.cu"
-    "2:factor_moe_fused_gemm.cu"
-)
-# Note: Factor 5 (GDN) uses FlashQLA Python extension, NOT a .so
-
-TOTAL=0
-SUCCESS=0
-for entry in "${FACTORS[@]}"; do
-    fid="${entry%%:*}"
-    cu_file="${CSRC_DIR}/${entry##*:}"
-    TOTAL=$((TOTAL + 1))
-    if [[ -f "$cu_file" ]]; then
-        if compile_factor "$fid" "$cu_file"; then
-            SUCCESS=$((SUCCESS + 1))
-        fi
-    else
-        echo "[EX] SKIP factor ${fid}: ${cu_file} not found"
-    fi
-done
-
-echo ""
-echo "========================================"
-echo "  Build complete: ${SUCCESS}/${TOTAL} factors (.so)"
-echo "  GDN: via FlashQLA (JIT compiled on hardware)"
-echo "  Output: ${BUILD_DIR}/"
-echo "========================================"
-ls -la "${BUILD_DIR}/" 2>/dev/null || true
+echo "[build.sh] DONE"
+ls -la build/*.so 2>/dev/null || echo "[build.sh] No .so files in build/"