Build & Infrastructure

This page covers the build-system, testing, and CI infrastructure changes carried in bwa-mem3 on top of upstream bwa-mem2.

doctest framework and Codecov (PR #34)

PR #34 establishes the long-term test infrastructure for bwa-mem3:

• doctest 2.4.11 is vendored as a single-header under ext/doctest/, with the SHA256 recorded in ext/doctest/VERSION.
• A new test/framework/ static library provides shared helpers: scoring matrices, deterministic sequence-pair generators, kswv-style batch packers, scalar and SIMD runners, kswr comparators, a JUnit reporter hook, and a shared main.
• Two test binaries are produced: bwa_mem3_tests_unit (runs on every CI matrix row) and bwa_mem3_tests_integration (runs on a subset of rows).
• The existing kswv_selftest is ported to test/unit/test_kswv_correctness.cpp — 30,049 assertions against scalar ksw_align2 on 10k random plus curated edge pairs.
• Five legacy integration sources are moved to test/integration/ via git mv; their binaries still emit at test/<name> so existing scripts keep working.
• Five inline CI bash regression blocks are extracted to test/regression/*.sh (phix_parity, chr22_parity, thread_determinism, bam_roundtrip, meth_oracle).
• A coverage CI job builds libbwa.a and both test binaries with COVERAGE=1 (-O0 --coverage), runs both test binaries, collects Cobertura XML via gcovr, and uploads to Codecov via codecov/codecov-action.

PACKAGE_VERSION from git describe (PR #52)

Before PR #52, src/main.cpp hardcoded PACKAGE_VERSION "2.2.1". This string appeared in bwa-mem3 version output and in the @PG VN: SAM header field but was never updated, causing every build to report an outdated version.

The Makefile now generates src/version.h from git describe --tags --dirty, falling back to a static FG_LABS_VERSION_FALLBACK when git describe cannot reach a tag (source-tarball extractions, shallow clones — e.g. CI with the default fetch-depth: 1). A write-if-changed mechanism (cmp -s + mv) regenerates the file on every invocation but only bumps its mtime when the stamped string changes, so only main.o is rebuilt when the version changes, not the entire tree. src/version.h is .gitignored and removed by make clean. Fixes issue #40. Related upstream: bwa-mem2#283, bwa-mem2#284.

PGO target parameterization (PR #59)

The original pgo-generate and pgo-use Makefile targets hardcoded arch=arm64 and a single shared pgo_profiles/ directory. PR #59 generalizes both:

• PGO_ARCH (default: arm64 on ARM hosts, native otherwise) passes through to the recursive make invocation as arch=$(PGO_ARCH). Accepts the same values as the rest of the Makefile: arm64, sse41, avx2, avx512bw, native, etc.
• PGO_PROFILE_DIR is now overridable (?= instead of =). Each (arch × training-regime) combination can capture into its own directory.
• When PGO_ARCH != arm64, the output binaries are named bwa-mem3.pgo-instr.<arch> and bwa-mem3.pgo.<arch> so multiple per-arch PGO builds coexist. The default arm64 names are unchanged for backward compatibility.
• pgo-clean now removes arch-suffixed PGO binaries in addition to bare names.

This enables the benchmarking workflow at bwa-mem3-bench, which requires per-arch × per-regime profile capture. See also Performance → PGO build.

CXXFLAGS/CPPFLAGS/LDFLAGS forwarding (PR #50)

The Makefile’s multi: rule compiled runsimd.cpp (the x86 multi-binary launcher) without honoring CXXFLAGS, CPPFLAGS, or LDFLAGS. The $(EXE) link honored CXXFLAGS and LDFLAGS but not CPPFLAGS.

PR #50 mirrors upstream bwa-mem2#290: the multi: compile now honors all three variables, and $(EXE) link adds $(CPPFLAGS). This allows downstream packagers (Debian, Bioconda) and reproducible-build systems to inject hardening flags (-D_FORTIFY_SOURCE=2, -fstack-protector-strong, -Wl,-z,relro) through the environment without patching the Makefile. No functional change unless the env vars are set. Closes issue #39.

Unit-test harness and ARM CI (PR #23)

Historically, PR #23 added a local bash harness (test/run_unit_tests.sh) that built and ran the five C++ unit binaries under test/ against committed fixtures in test/fixtures/, asserting exit 0 and non-empty diff-able output (those binaries have since been consolidated into the doctest harness — see the section above). It also fixes several pre-existing issues blocking the harness:

• test/Makefile defaulted to icpc (Intel compiler, not available on GitHub runners); changed to g++ on Linux x86.
• ARM flags are mirrored from the parent Makefile so cd test && make builds on macOS arm64 and Linux aarch64.
• Three test sources (smem2_test, bwt_seed_strategy_test, sa2ref_test) were missing the fmiSearch->load_index() call that fmi_test.cpp has, causing immediate segfaults on run.
• test/main_banded.cpp opened fksw.txt but never wrote to it; output is now written and main() returns 0 on success.
• Fixtures are added under test/fixtures/ covering phiX174, 50 bp test reads, BWT seed strategy inputs, SA pairs, and SW pairs.

CI matrix expansion (PR #24)

PR #24 stacks on PR #23 and expands the GitHub workflow .github/workflows/ci.yml from 5 matrix rows to 7:

The canonical row (row 2) adds: --bam=6 roundtrip record-count parity, thread-determinism (-t1 vs -t4 sorted diff), unit-test harness, chr22 pipeline parity vs bwa, SE smoke, interleaved smoke, and --meth Layers 1–3.

Changes catalog

See also: Developer Guide → Regression test framework · Developer Guide → Release process · Performance → PGO build · Performance improvements · Upstream PR status