nix: add building oid to the flake

OI's build is challenging and has often been a problem for the Open Source
community. It requires an extremely specific set of dependencies that are very
hard to achieve on most systems. There are frequent breakages, like when
updating to CentOS Stream 9, or when trying to update the CI's clang from
clang-12 to clang-15 - OI requires the clang libraries to be version 15 but
can't be compiled with it on the CI!

This changes provides a mostly working build environment with `nix`. This
environment is pinned to a specific nixpkgs revision using `flake.lock`, and
only updates when we explicitly tell it to.

Summary of changes:
- Update CMakeLists.txt required version to 3.24. This allows specifying
  `FIND_PACKAGE_ARGS` in `FetchContent`, meaning we can use system packages.
  This is available on most up to date distros (3.30.2 is current).
- Extends `flake.nix` to be able to build OI. Adds instructions for building
  and developing OI using `nix`.
- Partially runs the tests in GitHub Actions. A huge amount must be excluded
  because of incompatibilites between the clangStdenv compiler and drgn. We
  have similar, though fewer, issues when building with the clang-12/libstdcxx
  mix on the Ubuntu 22.04 CircleCI, though this is at least reproducible.
- Updates CircleCI to build CMake from source as we don't have a newer image
  available. Also add some newly found dependencies (not sure how it was
  working without them before).

Test plan:

This change requires less testing than previous build related changes because
it deprecates most of the build types.

- The internal BUCK build is unaffected. No special testing.
- The semi-internal CMake build is gone. Use Nix.
- The Nix build for clang-15 and some tests are continuously tested in GitHub
  actions.
- Tested the set of Nix commands in the README. All work except the one that
  points to GitHub as this must be merged first.
- The existing CircleCI runs on Ubuntu 20.04 are maintained.
- Unable to test the new `test-report.yml` as it must be merged due to the
  permissions it needs. Will follow up with testing after this is merged. See:
  https://github.com/dorny/test-reporter?tab=readme-ov-file#recommended-setup-for-public-repositories

The list of exclusions for GitHub Actions/nix testing is currently very long, I
think 29% of the tests. This should be stable and reproducible though, and
likely needs deep changes to OI to fix. That's why fixes are excluded from this
PR. It's all to do with the forked drgn not being able to parse clang's newer
DWARF output, and can't be fixed by rolling back as we required a relatively
new libcxx.

.circleci/config.yml

@@ -83,20 +83,26 @@ jobs:
               libgtest-dev \
               libjemalloc-dev \
               libmsgpack-dev \
+              libomp-12-dev \
+              liburing-dev \
               libzstd-dev \
               llvm-15-dev \
               ninja-build \
               pkg-config \
               python3-setuptools
             pip3 install toml
+
+            # Ubuntu 22.04 CMake is too old and we don't have a newer image yet
+            git clone --depth 1 --branch v3.30.2 https://github.com/Kitware/CMake.git /tmp/cmake
+            (cd /tmp/cmake && cmake -B build/ -G Ninja && cmake --build build/)
           environment:
             DEBIAN_FRONTEND: noninteractive
       - checkout
       - run:
           name: Build
           command: |
-            cmake -G Ninja -B build/ -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
-            cmake --build build/
+            /tmp/cmake/build/bin/cmake -G Ninja -B build/ -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
+            ninja -C build/
             # Testing rubbish:
             cp test/ci.oid.toml build/testing.oid.toml
       - persist_to_workspace:
@@ -131,10 +137,12 @@ jobs:
             sudo apt-get install -y \
               clang-15 \
               libboost-all-dev \
-              libgflags-dev \
-              llvm-15-dev \
               libfmt-dev \
-              libjemalloc-dev
+              libgflags-dev \
+              libgoogle-glog-dev \
+              libjemalloc-dev \
+              libomp-12-dev \
+              llvm-15-dev
           environment:
             DEBIAN_FRONTEND: noninteractive
       - run:

.github/workflows/ci.yml

@@ -0,0 +1,54 @@
+name: CI
+on:
+  pull_request:
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/[email protected]
+    - uses: cachix/install-nix-action@v27
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+    - name: nix fmt
+      run: |-
+        nix --experimental-features 'nix-command flakes' fmt
+        git diff --exit-code
+
+  build-test:
+    runs-on: 16-core-ubuntu
+    strategy:
+      matrix:
+        llvm_version: [15]
+    steps:
+    - uses: actions/[email protected]
+    - uses: cachix/install-nix-action@v27
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+    - name: build (LLVM ${{ matrix.llvm_version }})
+      # Run the build manually in `nix develop` to keep non-outputs around
+      run: |
+        nix develop .#oid-llvm${{ matrix.llvm_version }} --command cmake -B build -G Ninja -DWITH_FLAKY_TESTS=Off -DFORCE_BOOST_STATIC=Off
+        nix develop .#oid-llvm${{ matrix.llvm_version }} --command ninja -C build
+    - name: test (LLVM ${{ matrix.llvm_version }})
+      env:
+        # disable drgn multithreading as tests are already run in parallel
+        OMP_NUM_THREADS: 1
+      run: |
+        echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
+        nix develop .#oid-llvm${{ matrix.llvm_version }} --command ./tools/config_gen.py -c clang++ build/testing.oid.toml
+        nix develop .#oid-llvm${{ matrix.llvm_version }} --command ctest \
+          --test-dir build/test/ \
+          --test-action Test \
+          --parallel \
+          --no-compress-output \
+          --schedule-random \
+          --timeout 60 \
+          --repeat until-pass:2 \
+          --exclude-from-file ../../.github/workflows/tests_failing_under_nix.txt \
+          --output-junit results.xml
+    - name: upload results
+      uses: actions/upload-artifact@v4
+      if: success() || failure()
+      with:
+        name: test-results-${{ matrix.llvm_version }}
+        path: build/test/results.xml

.github/workflows/test-report.yml

@@ -0,0 +1,20 @@
+name: 'Test Report'
+on:
+  workflow_run:
+    workflows: ['CI']
+    types:
+      - completed
+permissions:
+  contents: read
+  actions: read
+  checks: write
+jobs:
+  report:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: dorny/test-reporter@v1
+      with:
+        artifact: test-results-15
+        name: CTest Tests
+        path: results.xml
+        reporter: jest-junit

.github/workflows/tests_failing_under_nix.txt

@@ -0,0 +1,235 @@
+AddChildrenTest.InheritancePolymorphic
+ClangTypeParserTest.MemberAlignment
+ClangTypeParserTest.SimpleStruct
+DrgnParserTest.ClassTemplateInt
+DrgnParserTest.Container
+DrgnParserTest.TemplateEnumValue
+DrgnParserTest.TemplateEnumValueGaps
+DrgnParserTest.TemplateEnumValueNegative
+OidIntegration.alignment_wrapper_member_alignment
+OidIntegration.alignment_wrapper_member_lower
+OidIntegration.alignment_wrapper_member_override
+OidIntegration.alignment_wrapper_struct
+OidIntegration.alignment_wrapper_two_members
+OidIntegration.alignment_wrapper_union_member
+OidIntegration.anonymous_anon_struct
+OidIntegration.anonymous_anon_typedef
+OidIntegration.anonymous_anon_union
+OidIntegration.anonymous_nested_anon_struct
+OidIntegration.anonymous_regular_struct
+OidIntegration.arrays_member_int0
+OidIntegration.arrays_member_int10
+OidIntegration.arrays_multidim
+OidIntegration.arrays_multidim_legacy
+OidIntegration.bitfields_enum
+OidIntegration.bitfields_mixed
+OidIntegration.bitfields_single
+OidIntegration.bitfields_straddle_bytes
+OidIntegration.bitfields_within_bytes
+OidIntegration.bitfields_zero_bits
+OidIntegration.cycles_raw_ptr
+OidIntegration.cycles_raw_ptr_wrapped
+OidIntegration.cycles_shared_ptr
+OidIntegration.cycles_unique_ptr
+OidIntegration.enums_params_scoped_enum_val
+OidIntegration.enums_params_scoped_enum_val_cast
+OidIntegration.enums_params_scoped_enum_val_gaps
+OidIntegration.enums_params_scoped_enum_val_negative
+OidIntegration.enums_params_unscoped_enum_val_cast
+OidIntegration.fbstring_empty
+OidIntegration.fbstring_heap_allocated
+OidIntegration.fbstring_inline
+OidIntegration.fbstring_string_pooled_unique
+OidIntegration.folly_f14_fast_map_a
+OidIntegration.folly_f14_fast_set_a
+OidIntegration.folly_f14_node_map_a
+OidIntegration.folly_f14_node_set_a
+OidIntegration.folly_f14_value_map_a
+OidIntegration.folly_f14_value_set_a
+OidIntegration.folly_f14_vector_map_a
+OidIntegration.folly_f14_vector_set_a
+OidIntegration.folly_small_vector_int_always_heap
+OidIntegration.folly_small_vector_int_default_empty
+OidIntegration.folly_small_vector_int_default_inlined
+OidIntegration.folly_small_vector_int_default_overflow
+OidIntegration.folly_small_vector_vector_3_empty
+OidIntegration.folly_small_vector_vector_3_inlined
+OidIntegration.folly_small_vector_vector_3_overflow
+OidIntegration.folly_sorted_vector_map_int_int_empty
+OidIntegration.folly_sorted_vector_map_int_int_reserve
+OidIntegration.folly_sorted_vector_map_int_int_some
+OidIntegration.ignored_member
+OidIntegration.ignored_roottype
+OidIntegration.ignored_subtype
+OidIntegration.inheritance_access_private
+OidIntegration.inheritance_access_protected
+OidIntegration.inheritance_access_public
+OidIntegration.inheritance_access_public_as_base
+OidIntegration.inheritance_multiple_a
+OidIntegration.inheritance_polymorphic_a_as_a
+OidIntegration.inheritance_polymorphic_b_as_a
+OidIntegration.inheritance_polymorphic_b_as_b
+OidIntegration.inheritance_polymorphic_c_as_a
+OidIntegration.inheritance_polymorphic_c_as_b
+OidIntegration.inheritance_polymorphic_c_as_c
+OidIntegration.inheritance_polymorphic_diamond_child_as_child
+OidIntegration.inheritance_polymorphic_diamond_child_as_middle1
+OidIntegration.inheritance_polymorphic_diamond_child_as_middle1_root
+OidIntegration.inheritance_polymorphic_diamond_child_as_middle2
+OidIntegration.inheritance_polymorphic_diamond_child_as_middle2_root
+OidIntegration.inheritance_polymorphic_diamond_middle1_as_middle1
+OidIntegration.inheritance_polymorphic_diamond_middle1_as_root
+OidIntegration.inheritance_polymorphic_diamond_middle2_as_middle2
+OidIntegration.inheritance_polymorphic_diamond_middle2_as_root
+OidIntegration.inheritance_polymorphic_diamond_root_as_root
+OidIntegration.inheritance_polymorphic_non_dynamic_base_a_as_a
+OidIntegration.inheritance_polymorphic_non_dynamic_base_a_no_polymorphic
+OidIntegration.inheritance_polymorphic_non_dynamic_base_b_as_a
+OidIntegration.inheritance_polymorphic_non_dynamic_base_b_as_b
+OidIntegration.inheritance_polymorphic_non_dynamic_base_b_no_polymorphic
+OidIntegration.inheritance_polymorphic_non_dynamic_base_c_as_a
+OidIntegration.inheritance_polymorphic_non_dynamic_base_c_as_b
+OidIntegration.inheritance_polymorphic_non_dynamic_base_c_as_c
+OidIntegration.inheritance_polymorphic_non_dynamic_base_c_no_polymorphic
+OidIntegration.multi_arg_tb_all_fail_crashes
+OidIntegration.multi_arg_tb_fail_first_arg
+OidIntegration.namespaces_queue
+OidIntegration.namespaces_stack
+OidIntegration.packed_a
+OidIntegration.padding_bool_padding
+OidIntegration.padding_nested_padding
+OidIntegration.pointers_feature_config
+OidIntegration.pointers_feature_flag_disabled
+OidIntegration.pointers_incomplete_containing_struct
+OidIntegration.pointers_incomplete_containing_struct_no_follow
+OidIntegration.pointers_incomplete_shared_ptr
+OidIntegration.pointers_incomplete_shared_ptr_null
+OidIntegration.pointers_incomplete_unique_ptr
+OidIntegration.pointers_incomplete_unique_ptr_null
+OidIntegration.pointers_struct_primitive_ptrs
+OidIntegration.pointers_struct_primitive_ptrs_no_follow
+OidIntegration.pointers_struct_primitive_ptrs_null
+OidIntegration.pointers_struct_vector_ptr
+OidIntegration.pointers_struct_vector_ptr_no_follow
+OidIntegration.pointers_struct_vector_ptr_null
+OidIntegration.pointers_vector_of_pointers
+OidIntegration.primitives_long_double
+OidIntegration.simple_class
+OidIntegration.simple_struct
+OidIntegration.simple_union
+OidIntegration.sorted_vector_set_no_ints
+OidIntegration.sorted_vector_set_some_ints
+OidIntegration.std_array_uint64_length_0
+OidIntegration.std_array_uint64_length_1
+OidIntegration.std_array_uint64_length_8
+OidIntegration.std_array_vector_length_1
+OidIntegration.std_array_vector_length_2
+OidIntegration.std_conditional_a
+OidIntegration.std_deque_del_allocator_a
+OidIntegration.std_deque_deque_int_empty
+OidIntegration.std_deque_deque_int_some
+OidIntegration.std_deque_int_empty
+OidIntegration.std_deque_int_some
+OidIntegration.std_list_del_allocator_a
+OidIntegration.std_list_int_empty
+OidIntegration.std_list_int_some
+OidIntegration.std_list_list_int_empty
+OidIntegration.std_list_list_int_some
+OidIntegration.std_list_struct_some
+OidIntegration.std_map_custom_comparator_a
+OidIntegration.std_multimap_custom_comparator_a
+OidIntegration.std_multiset_custom_comparator_a
+OidIntegration.std_optional_uint64_empty
+OidIntegration.std_optional_uint64_present
+OidIntegration.std_optional_vector_empty
+OidIntegration.std_optional_vector_present
+OidIntegration.std_pair_uint64_uint32
+OidIntegration.std_pair_uint64_uint64
+OidIntegration.std_pair_vector_vector
+OidIntegration.std_priority_queue_adapter_deque_empty
+OidIntegration.std_priority_queue_adapter_deque_some
+OidIntegration.std_priority_queue_int_empty
+OidIntegration.std_priority_queue_int_some
+OidIntegration.std_queue_adapter_vector_empty
+OidIntegration.std_queue_adapter_vector_some
+OidIntegration.std_queue_int_empty
+OidIntegration.std_queue_int_some
+OidIntegration.std_queue_queue_int_empty
+OidIntegration.std_queue_queue_int_some
+OidIntegration.std_reference_wrapper_int
+OidIntegration.std_reference_wrapper_vector
+OidIntegration.std_set_custom_comparator_a
+OidIntegration.std_smart_ptr_shared_ptr_const_uint64_empty
+OidIntegration.std_smart_ptr_shared_ptr_const_vector_empty
+OidIntegration.std_smart_ptr_shared_ptr_uint64_empty
+OidIntegration.std_smart_ptr_shared_ptr_uint64_present
+OidIntegration.std_smart_ptr_shared_ptr_vector_empty
+OidIntegration.std_smart_ptr_shared_ptr_vector_present
+OidIntegration.std_smart_ptr_shared_ptr_void_empty
+OidIntegration.std_smart_ptr_shared_ptr_void_present
+OidIntegration.std_smart_ptr_unique_ptr_const_uint64_empty
+OidIntegration.std_smart_ptr_unique_ptr_const_vector_empty
+OidIntegration.std_smart_ptr_unique_ptr_uint64_empty
+OidIntegration.std_smart_ptr_unique_ptr_uint64_present
+OidIntegration.std_smart_ptr_unique_ptr_vector_empty
+OidIntegration.std_smart_ptr_unique_ptr_vector_present
+OidIntegration.std_smart_ptr_unique_ptr_void_empty
+OidIntegration.std_smart_ptr_unique_ptr_void_present
+OidIntegration.std_smart_ptr_weak_ptr_int64_empty
+OidIntegration.std_smart_ptr_weak_ptr_int64_expired
+OidIntegration.std_smart_ptr_weak_ptr_int64_expired_chase
+OidIntegration.std_smart_ptr_weak_ptr_int64_present
+OidIntegration.std_smart_ptr_weak_ptr_int64_present_chase
+OidIntegration.std_smart_ptr_weak_ptr_int64_void_empty
+OidIntegration.std_stack_adapter_vector_empty
+OidIntegration.std_stack_adapter_vector_some
+OidIntegration.std_stack_int_empty
+OidIntegration.std_stack_int_some
+OidIntegration.std_stack_stack_int_empty
+OidIntegration.std_stack_stack_int_some
+OidIntegration.std_string_empty
+OidIntegration.std_string_heap_allocated
+OidIntegration.std_string_sso
+OidIntegration.std_tuple_uint64_uint64
+OidIntegration.std_unordered_map_custom_operator_a
+OidIntegration.std_unordered_multimap_custom_operator_a
+OidIntegration.std_unordered_multiset_custom_operator_a
+OidIntegration.std_unordered_set_custom_operator_a
+OidIntegration.std_variant_256_params_256
+OidIntegration.std_variant_256_params_empty
+OidIntegration.std_variant_char_int64_1
+OidIntegration.std_variant_char_int64_2
+OidIntegration.std_variant_empty
+OidIntegration.std_variant_optional
+OidIntegration.std_variant_vector_int_1
+OidIntegration.std_variant_vector_int_2
+OidIntegration.std_vector_del_allocator_a
+OidIntegration.std_vector_int_empty
+OidIntegration.std_vector_int_some
+OidIntegration.std_vector_reserve
+OidIntegration.std_vector_struct_some
+OidIntegration.std_vector_vector_int_empty
+OidIntegration.std_vector_vector_int_some
+OidIntegration.templates_int
+OidIntegration.templates_two
+OidIntegration.templates_value
+OidIntegration.templates_vector
+OidIntegration.typedefed_parent_multilevel_typedef_parent
+OidIntegration.typedefed_parent_simple_typedef_parent
+OidIntegration.typedefs_anonymous
+OidIntegration.typedefs_container
+OidIntegration.unions_alignment
+OidIntegration.unions_int
+OidIntegration.unions_tagged_int
+OidIntegration.unions_tagged_unordered_map
+OidIntegration.unions_tagged_vector
+OidIntegration.unions_unordered_map
+OidIntegration.unions_vector
+OilIntegration.folly_f14_fast_map_a
+OilIntegration.folly_f14_fast_set_a
+OilIntegration.folly_f14_node_map_a
+OilIntegration.folly_f14_node_set_a
+OilIntegration.folly_f14_value_map_a
+OilIntegration.folly_f14_value_set_a
+OilIntegration.folly_f14_vector_map_a
+OilIntegration.folly_f14_vector_set_a