Add ACT4 user-mode test coverage

[cyrilmhansen]

Summary

This PR brings up ACT4 user-mode architectural testing for rv32emu's RV32IMAF(C) configuration and fixes the main emulator issues exposed by those tests.

Related issue: #730

Changes include:

• Add the rv32emu Sail configuration needed by ACT4.
• Expand the default ACT user-mode batch to the currently passing extension set: I,M,F,Zicsr,Zicntr,Zifencei,Zca,Zcf,Misalign,MisalignZca,Zaamo.
• Filter the ACT runner by ACT_EXTENSIONS, so targeted runs such as ACT_EXTENSIONS=F do not execute stale ELFs from earlier batches.
• Prefer the ACT Sail 0.11 tool directory during ACT ELF generation so sail_riscv_sim --version does not pick the older arch-test prebuilt.
• Fix x0 handling in interpreter execution and constant propagation.
• Fix RV32F CSR handling for fflags, frm, and fcsr.
• Merge the latest upstream master activity through 7b4e872 / PR Refine WebAssembly user/system mode demos #732.
• Disable block chaining and MOP fusion in the architecture-test CI config to keep the ACT user-mode path deterministic while optimizer-specific issues are handled separately.

Notes

Zalrsc is intentionally not included in the default ACT batch yet. Zalrsc-sc.w still reaches the ACT fail halt path even when the dumped signature matches Sail's generated .results, so it needs separate LR/SC/tohost investigation before being enabled as a default passing batch.

The x0 repair is deliberately conservative and may warrant upstream review for hot-path performance. The FP CSR fix is architectural correctness and should not be gated behind an optimization flag.

Interpreter loop-fusion optimization work has been split out of this ACT PR and now lives on codex/interpreter-loop-fusions (71a6666).

Licensing

The ACT4 checkout is kept as a submodule. The local ACT tree documents code licensing as BSD-3-Clause or Apache-2.0, with documentation under CC-BY-4.0, and includes the corresponding license texts.

Testing

• PKG_CONFIG=/usr/bin/pkg-config make -j4 with JIT+T2C
• PKG_CONFIG=/usr/bin/pkg-config make ci_defconfig && PKG_CONFIG=/usr/bin/pkg-config make -j4
• GEM_HOME=$PWD/build/act-tools/gems/ruby/3.4.0 GEM_PATH=$PWD/build/act-tools/gems/ruby/3.4.0:/home/john/.local/share/gem/ruby/3.4.0 BUNDLE_PATH=$PWD/build/act-tools/gems PATH=$PWD/build/act-tools/gems/ruby/3.4.0/bin:/home/john/.local/share/gem/ruby/3.4.0/bin:/home/john/projects/github/rv32emu/.venv/bin:$PATH PKG_CONFIG=/usr/bin/pkg-config make act-user-run ACT_EXTENSIONS=I -> ACT runner: 39/39 passed

Earlier broad generated ACT batches were also checked with the direct runner:

• tools/run-act-elfs.sh build/rv32emu-user build/act/rv32emu-rv32imafc/elfs I,M,F,Zicsr,Zicntr,Zifencei,Zca,Zcf,Misalign,MisalignZca,Zaamo -> ACT runner: 182/182 passed
• tools/run-act-elfs.sh build/rv32emu-user build/act/rv32emu-rv32imafc/elfs F -> ACT runner: 78/78 passed

---

Summary by cubic

Adds ACT4 user-mode tests for rv32emu RV32IMAF(C), fixes FCSR/x0 correctness, and speeds up the interpreter with new loop fusions. CI runs stay deterministic, and ACT runs are filterable via ACT_EXTENSIONS.

• New Features

  • ACT4 integration: tests/riscv-act submodule, rv32emu config (Sail JSON, linker, YAML), and tools/run-act-elfs.sh; new act-user-elfs/act-user-run with ACT_EXTENSIONS; prefers Sail 0.11 via ACT_SAIL_BIN_DIR.
  • Interpreter-only fusions: ADDI+ADDI+BNE and ADDI+conditional-branch loops; ~1.22x speedup on an RV32IM microbench; JIT/T2C builds unaffected via stubs.
  • Build/test flow: RISCOF accepts dut_exe; separate rv32emu-user and rv32emu-system; env detection supports LLVM 18–21 (HAVE_LLVM), uses tools/detect-env.py for SDL checks, and respects PKG_CONFIG; toolchain detection adds riscv32-elf-/riscv64-elf-.

• Bug Fixes

  • Enforced x0=0 in the interpreter loop and constant propagation; corrected RV32F CSR reads/writes for fflags, frm, and fcsr.
  • CI/build stability: disabled block chaining and MOP fusion for deterministic ACT runs; guarded user-mode demos/tests in system builds; minor fixes in riscv.c, SDL_mixer vars, and DTB dependency.

^{Written for commit 67b9f80. Summary will update on new commits. Review in cubic}

[jserv]

Benchmarks

Details

Benchmark suite	Current: 67b9f80	Previous: 1456c8a	Ratio
Dhrystone	1563.333 DMIPS	1569.333 DMIPS	1.00
CoreMark	1088.292 iterations/sec	1121.207 iterations/sec	1.03

This comment was automatically generated by workflow using github-action-benchmark.