extract-asm-syclkernel-aot

name	extract-asm-syclkernel-aot
description	Extract GPU ISA from AOT-compiled SYCL binaries using NEO driver runtime dump. Use when the kernel is a SYCL symbol (_ZTS...) from an AOT binary such as libtorch_xpu.so, SYCL-TLA FMHA, or any DPC++ binary compiled with -fsycl-targets=spir64_gen -Xs "-device <gpu>".

Extract ASM from AOT-Compiled SYCL Binaries

Key facts

• GPU ISA (zebin) was already compiled at build time by IGC and embedded in the host binary.
• IGC_ShaderDumpEnable does NOT work — IGC is never invoked at runtime.
• Extraction uses NEO driver debug keys to dump the zebin ELF at runtime, then ocloc disasm to produce readable ASM.

When to use

• Kernel is a mangled SYCL symbol (_ZTS…) from an AOT-compiled binary whose AOT target matches the current device:
  • libtorch_xpu.so / libtorch_xpu_ops.so (default PyTorch XPU build)
  • SYCL-TLA FMHA .so
  • Standalone DPC++ executable built with -fsycl-targets=spir64_gen

When NOT to use

• AOT target does not match current device (e.g. binary built for PVC, running on BMG) → runtime falls back to JIT → use extract-asm-syclkernel-jit
• Binary has no AOT code at all → use extract-asm-syclkernel-jit
• Kernel is oneDNN ngen (gemm_kernel, gen_conv_kernel) → use extract-asm-onednn
• Kernel is Triton (triton_*) → use extract-asm-triton

Steps

Step 1: Verify tools

command -v ocloc >/dev/null || { echo "ocloc not found; source oneapi-vars.sh"; exit 1; }

Step 2: Dump zebin ELFs via NEO driver

Run the workload with NEO debug keys. Only kernels actually dispatched to the GPU will be dumped — no unused kernels appear.

OUT="<workdir>/aot_$(date +%Y%m%d_%H%M%S)"
mkdir -p "$OUT" && cd "$OUT"

DumpZEBin=1 NEOReadDebugKeys=1 <repro_cmd>
ls *.elf

Step 3: Disassemble

# Detect device name (bmg, dg2, pvc, etc.)
DEVICE=$(sycl-ls 2>/dev/null | grep -oP '(?<=\[)[^]]+' | head -1 | awk '{print tolower($NF)}')
DEVICE=${DEVICE:-bmg}  # fallback

for elf in *.elf; do
  name=$(basename "$elf" .elf)
  ocloc disasm -file "$elf" -dump "${name}_dump" -device "$DEVICE"
done

Step 4: Identify the target kernel

ASM files are at <name>_dump/.text._ZTSxxxx.asm. Demangle to find yours:

for f in *_dump/.text._ZTS*.asm; do
  mangled=$(basename "$f" .asm | sed 's/^\.text\.//')
  echo "$f  →  $(c++filt "$mangled")"
done

Match the demangled name to the kernel you are analyzing.