[Infra][Build] Unified Multi-Target Build Manager

[copparihollmann]

Context

We currently maintain multiple bash scripts (build_debug_asan.sh, riscv_spacemit/build_debug.sh, etc.) to handle diverse build configurations. This fragmentation makes it hard for Agents to reliably "build the project." We need a single Python source of truth (src/tools/builder.py) that abstracts these flags.

Objective

Upgrade the run_build python tool to support a profile argument that maps to our specific CMake presets.

Scope of Work

1. Profile Registry: Implement the following profiles in builder.py:
   • HOST_DEBUG: Standard RelWithDebInfo.
   • HOST_ASAN: Clang + LD_PRELOAD + ASAN flags (Derived from build_debug_asan.sh).
   • RISCV_FIRESIM: Bare-metal cross-compilation using riscv_firesim.toolchain.cmake and linker specs.
   • RISCV_SPACEMIT: Linux cross-compilation for SpacemiT K1 using riscv.toolchain.cmake.
2. Environment Management:
   • Auto-detect RISCV_TOOLCHAIN_ROOT or fail gracefully.
   • Handle LD_PRELOAD injection for Python subprocesses when running ASAN builds.

Acceptance Criteria

• Test 1 (Host): builder.py build --profile host_debug -> Success if iree-compile is generated.
• Test 2 (ASAN): builder.py build --profile host_asan -> Success if libclang_rt.asan.so is correctly preloaded and binary runs without segfault.
• Test 3 (RISC-V): builder.py build --profile riscv_firesim -> Success if it invokes the specific gcc linker script (htif.ld) defined in the toolchain file.