bazel: add code coverage build option

[napetrov]

Description

Add a typed Bazel --code_coverage=true option corresponding to Make CODE_COVERAGE=yes for supported Linux Intel compiler builds.

This is a focused Make-to-Bazel option-parity improvement toward #3530. The option is disabled by default and does not instrument external dependencies.

What changed

• add the typed boolean --code_coverage=true interface
• apply Make-compatible host compile/link coverage options only to oneDAL-owned actions
• scope GCOV_BUILD to Make CORE.objs_a/y-equivalent DAAL modules
• keep separately built threading, oneAPI DAL, DPC++, tests, examples, and tools outside the GCOV_BUILD define scope
• use -Xscoverage for DPC++ link actions while leaving DPC++ compilation unchanged
• preserve coverage runtime linkage for instrumented executable/test actions
• reject unsupported OS/compiler selections clearly
• document the action-level mapping and add a bounded GCC negative smoke to CI

Validation

Validated on Linux before push; pushed exact head is d7002469af09b3f84cab54af2d57ed5df9f032c3 (the final two changes after validation were comment/table-whitespace only).

Focused action matrix

ICX/DPC++ Bazel aquery checks verified:

• DAAL core compile: GCOV_BUILD and -coverage
• threading compile: -coverage, no GCOV_BUILD
• oneAPI host compile: -coverage, no GCOV_BUILD
• DPC++ compile: neither -coverage nor GCOV_BUILD
• host module/final/executable/test links: -coverage
• DPC++ links: -Xscoverage
• static archives: no coverage linker option
• default-off actions: no coverage tokens
• no coverage flags leaked into external dependency actions

Build/test proof

CC=icx CXX=icpx bazelisk test \
  //cpp/daal/src/algorithms/dtrees/gbt/regression:test_gbt_regression_model_builder_unit_host \
  --code_coverage=true --cpu=sse2 --jobs=2 --test_output=errors

Result: 1/1 passed. The run produced 152 .gcda files.

CC=icx CXX=icpx bazelisk build \
  //cpp/oneapi/dal/table:table_dpc \
  --code_coverage=true --release_dpc=true --cpu=sse2 --jobs=2

Result: passed with the real DPC++ module link using -Xscoverage.

GCC selection was also verified to fail analysis with the intended diagnostic. CI YAML parse, git diff --check, and git show --check passed.

Scope notes

Make enables this mode only for CODE_COVERAGE=yes on Linux. Bazel is stricter: unsupported targets/compiler selections fail clearly instead of silently disabling coverage. Static archive actions remain flag-free; final executable/test links receive the coverage driver option needed to resolve the runtime from instrumented objects.

Review

Independent final review: APPROVE. Two documentation-only suggestions were applied before push.

---

Checklist

• Changes reviewed locally
• Documentation updated
• Commits include Signed-off-by
• Focused ICX host and DPC++ build/test validation completed
• Default behavior unchanged
• Unsupported selections fail clearly
• No production performance effect unless explicitly enabled

[Copilot]

Pull request overview

Adds a Bazel-typed --code_coverage=true build option to mirror Make’s CODE_COVERAGE=yes for supported Linux ICX builds, applying coverage instrumentation in an action-local way (oneDAL-owned actions only) and documenting/validating the mapping in CI.

Changes:

• Introduce a new typed Bazel flag (@config//:code_coverage) with a .bazelrc alias --code_coverage.
• Add action-local coverage compile/link flags for oneDAL rules, with GCOV_BUILD scoped to DAAL core modules and a DPC++ link-mode mapping (-Xscoverage).
• Document behavior and add CI smoke tests (negative GCC rejection + positive ICX aquery-based verification).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
INSTALL.md	Documents Bazel equivalent of Make coverage mode and its scoping rules.
dev/bazel/tests/code_coverage_test.sh	Adds an ICX positive-path smoke that validates action flags via bazel aquery.
dev/bazel/tests/BUILD	Exports the new coverage smoke script.
dev/bazel/README.md	Documents the Make→Bazel mapping and the action-level coverage behavior table.
dev/bazel/daal.bzl	Adds define_gcov_build plumbing so DAAL modules can opt into GCOV_BUILD under coverage.
dev/bazel/config/config.tpl.BUILD	Introduces the typed boolean build setting code_coverage.
dev/bazel/cc.bzl	Implements coverage flag injection for compile/link actions and prevents transitive leakage.
cpp/daal/BUILD	Explicitly disables GCOV_BUILD for the separately built DAAL threading module.
.ci/pipeline/ci.yml	Adds GCC rejection smoke and ICX positive coverage smoke build to CI.
.bazelrc	Adds a --flag_alias for code_coverage.

[david-cortes-intel]

Would this actually get used if the public CI jobs are not running anything with GPUs?