0.1.0 —— C++ 运行时上到 openkal,连同编译器自己的运行时和裸机的展开约定 #6
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| name: CI | |
| # What this workflow asserts. | |
| # | |
| # A C++ standard library is not portable in the sense a program is: it is | |
| # configured for one C library and compiled against that library's headers. The | |
| # claim here is therefore not "it builds" but "a program above it does the | |
| # things a C++ program does", and the one that settles it is an exception thrown | |
| # across frames and caught --- because that is the path a build proves nothing | |
| # about. Everything else this package could check, a runtime that was linked but | |
| # never worked would also satisfy. | |
| on: | |
| push: | |
| branches: [main] | |
| pull_request: | |
| workflow_dispatch: | |
| env: | |
| MCPP_VERSION: 2026.8.19.4 | |
| XLINGS_VERSION: v2026.8.17.2 | |
| XLINGS_NON_INTERACTIVE: '1' | |
| jobs: | |
| runtime: | |
| name: build the runtime and run what stands above it (${{ matrix.toolchain }}) | |
| runs-on: ubuntu-24.04 | |
| timeout-minutes: 60 | |
| strategy: | |
| fail-fast: false | |
| matrix: | |
| toolchain: ['llvm@22.1.8'] | |
| defaults: | |
| run: | |
| shell: bash | |
| steps: | |
| - uses: actions/checkout@v4 | |
| - name: Install xlings and mcpp | |
| run: | | |
| curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh \ | |
| | bash -s "$XLINGS_VERSION" | |
| echo "$HOME/.xlings/subos/current/bin" >> "$GITHUB_PATH" | |
| - name: Install mcpp | |
| run: | | |
| for attempt in 1 2 3 4 5 6; do | |
| xlings update > /dev/null 2>&1 || true | |
| if xlings install "mcpp@$MCPP_VERSION" -y -g; then break; fi | |
| if [ "$attempt" = 6 ]; then | |
| echo "::error::mcpp@$MCPP_VERSION never appeared in the index"; exit 1 | |
| fi | |
| sleep 60 | |
| done | |
| mcpp --version | |
| mcpp self config --mirror GLOBAL | |
| - name: Select the toolchain | |
| run: | | |
| spec='${{ matrix.toolchain }}' | |
| mcpp toolchain install "${spec%@*}" "${spec#*@}" | |
| mcpp toolchain default "$spec" | |
| - name: The runtime builds | |
| run: mcpp build | |
| # ⚠️ THE ONE OBSERVATION A BUILD CANNOT MAKE. | |
| # | |
| # An unwinder that cannot find the program's frame descriptions compiles, | |
| # links, and runs every path that does not throw. Measured while this | |
| # package was written: the whole example above printed its first line and | |
| # then `libc++abi: terminating due to uncaught exception', with | |
| # _Unwind_Backtrace walking zero frames --- and nothing named the cause. | |
| # So the throw is the check, and the destructor beside it is what says the | |
| # unwind was correct rather than merely non-fatal. | |
| - name: A C++ program above it throws across frames and catches | |
| run: | | |
| cd examples/cxx && mcpp run 2>&1 | tee out.log | |
| grep -q -- '-- failures: 0 --' out.log | |
| - name: import std above it | |
| run: | | |
| cd examples/import-std && mcpp run 2>&1 | tee out.log | |
| grep -q 'import std above openkal: 2 4 7' out.log | |
| # ⭐⭐ THE SAME PROGRAM ON A MACHINE WITH NO OPERATING SYSTEM. | |
| # | |
| # Everything above this step runs on a host, and a host has a C library, a | |
| # C++ runtime and an unwinder already installed. A program that reaches | |
| # one of them by mistake still works — so those steps can pass without | |
| # having exercised this package's own copies at all. | |
| # | |
| # There is nothing here to reach. The C library is openkal-musl, the | |
| # standard library and the unwinder are this package's, and beneath them | |
| # is firmware whose whole interface is `ecall`. ⇒ This is the step that | |
| # cannot go green by accident, which is why the design document makes it | |
| # the acceptance criterion rather than one more row. | |
| # | |
| # ⚠️ The assertion is on the OUTPUT and not on the exit status: firmware | |
| # that never reaches the payload exits zero, and so does a payload whose | |
| # console writes go nowhere. | |
| - name: Install the emulator | |
| if: matrix.toolchain == 'llvm@22.1.8' | |
| run: | | |
| xlings install xim:qemu-riscv -y | |
| XLINGS_HOME="$HOME/.mcpp/registry" xlings install xim:qemu-riscv -y | |
| # ⚠️ THE BUILD TOOL IS BUILT FROM A BRANCH, AND THAT IS TEMPORARY. | |
| # | |
| # This step needs four decisions that no released mcpp makes yet, each of | |
| # which belongs to the tool rather than to this package: | |
| # | |
| # `import std` is gated on whether a package PROVIDES a standard | |
| # library for the target rather than on whether the target is | |
| # freestanding; a package may carry its own std module source; | |
| # `-fno-exceptions` / `-fno-rtti` / `-ffreestanding` come off when the | |
| # graph supplies a C++ runtime built for the target; and unwind tables | |
| # go on, because the compiler turns them off for this kind of target | |
| # and a partial set of tables stops the walk rather than degrading it. | |
| # | |
| # They are on mcpp-community/mcpp#486. Until that is released this job | |
| # builds the tool the same way every other dependency here is taken — | |
| # from the branch — so the criterion below is actually enforced instead | |
| # of being a comment saying it was verified once on a laptop. | |
| # | |
| # ⇒ When #486 ships, delete this step and raise MCPP_VERSION. | |
| - name: The build tool, from the branch that has what this needs | |
| if: matrix.toolchain == 'llvm@22.1.8' | |
| run: | | |
| set -euo pipefail | |
| git clone --depth 1 -b feat/import-std-capability \ | |
| https://github.com/mcpp-community/mcpp "$RUNNER_TEMP/mcpp-src" | |
| cd "$RUNNER_TEMP/mcpp-src" | |
| mcpp build --release | |
| BUILT=$(find target -type f -name mcpp -perm -u+x | head -1) | |
| [ -n "$BUILT" ] || { echo "::error::mcpp did not build"; exit 1; } | |
| echo "$(cd "$(dirname "$BUILT")" && pwd)" >> "$GITHUB_PATH" | |
| "$BUILT" --version | |
| - name: The same program on bare metal, with exceptions | |
| if: matrix.toolchain == 'llvm@22.1.8' | |
| run: | | |
| set -euo pipefail | |
| cd examples/baremetal | |
| Q=$(ls -d "$HOME"/.mcpp/registry/data/xpkgs/xim-x-qemu-riscv/*/bin/qemu-system-riscv64 | head -1) | |
| sed -i "s|\"qemu-system-riscv64\"|\"$Q\"|" mcpp.toml | |
| mcpp run 2>&1 | tee out.log | |
| grep -q 'sorted: 2 4 7' out.log # containers + algorithms + the allocator | |
| grep -q 'caught: 42' out.log # the unwinder found the handler | |
| grep -q 'unwound: true' out.log # ⭐ and ran a destructor on the way | |
| grep -q 'baremetal import std: ok' out.log |