# needs-profiler-support
# ignore-windows-gnu

# FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
# properly. Since we only have GCC on the CI ignore the test for now.

# ISSUE(76038): When targeting MSVC, Rust binaries built with both `-Z instrument-coverage` and
# `-C link-dead-code` typically crash (with a seg-fault) or at best generate an empty `*.profraw`.
# See ../coverage/coverage_tools.mk for more information.

-include ../coverage/coverage_tools.mk

BASEDIR=../coverage-reports-base
SOURCEDIR=../coverage

all: $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))

# Ensure there are no `expected` results for tests that may have been removed or renamed
.PHONY: clear_expected_if_blessed
clear_expected_if_blessed:
ifdef RUSTC_BLESS_TEST
	rm -f expected_export_coverage.*.json
	rm -f expected_show_coverage.*.txt
endif

-include clear_expected_if_blessed

%: $(SOURCEDIR)/%.rs
	# Compile the test program with coverage instrumentation and generate relevant MIR.
	$(RUSTC) $(SOURCEDIR)/$@.rs \
			-Zinstrument-coverage \
			-Clink-dead-code=$(LINK_DEAD_CODE)

	# Run it in order to generate some profiling data,
	# with `LLVM_PROFILE_FILE=<profdata_file>` environment variable set to
	# output the coverage stats for this run.
	LLVM_PROFILE_FILE="$(TMPDIR)"/$@.profraw \
			$(call RUN,$@) || \
			( \
				status=$$?; \
				grep -q "^\/\/ expect-exit-status-$$status" $(SOURCEDIR)/$@.rs || \
				( >&2 echo "program exited with an unexpected exit status: $$status"; \
					false \
				) \
			)

	# Postprocess the profiling data so it can be used by the llvm-cov tool
	"$(LLVM_BIN_DIR)"/llvm-profdata merge --sparse \
			"$(TMPDIR)"/$@.profraw \
			-o "$(TMPDIR)"/$@.profdata

	# Generate a coverage report using `llvm-cov show`. The output ordering
	# can be non-deterministic, so ignore the return status. If the test fails
	# when comparing the JSON `export`, the `show` output may be useful when
	# debugging.
	"$(LLVM_BIN_DIR)"/llvm-cov show \
			--Xdemangler="$(RUST_DEMANGLER)" \
			--show-line-counts-or-regions \
			--instr-profile="$(TMPDIR)"/$@.profdata \
			$(call BIN,"$(TMPDIR)"/$@) \
		> "$(TMPDIR)"/actual_show_coverage.$@.txt

ifdef RUSTC_BLESS_TEST
	cp "$(TMPDIR)"/actual_show_coverage.$@.txt expected_show_coverage.$@.txt
else
	# Compare the show coverage output (`--bless` refreshes `typical` files)
	# Note `llvm-cov show` output for some programs can vary, but can be ignored
	# by inserting `// ignore-llvm-cov-show-diffs` at the top of the source file.

	$(DIFF) expected_show_coverage.$@.txt "$(TMPDIR)"/actual_show_coverage.$@.txt || \
		( grep -q '^\/\/ ignore-llvm-cov-show-diffs' $(SOURCEDIR)/$@.rs && \
			>&2 echo 'diff failed, but suppressed with `// ignore-llvm-cov-show-diffs` in $(SOURCEDIR)/$@.rs' \
		) || \
		( >&2 echo 'diff failed, and not suppressed without `// ignore-llvm-cov-show-diffs` in $(SOURCEDIR)/$@.rs'; \
			false \
		)

endif

	# Generate a coverage report in JSON, using `llvm-cov export`, and fail if
	# there are differences from the expected output.
	"$(LLVM_BIN_DIR)"/llvm-cov export \
			--summary-only \
			--instr-profile="$(TMPDIR)"/$@.profdata \
			$(call BIN,"$(TMPDIR)"/$@) \
		| "$(PYTHON)" $(BASEDIR)/prettify_json.py \
		> "$(TMPDIR)"/actual_export_coverage.$@.json

ifdef RUSTC_BLESS_TEST
	cp "$(TMPDIR)"/actual_export_coverage.$@.json expected_export_coverage.$@.json
else
	# Check that exported JSON coverage data matches what we expect (`--bless` refreshes `expected`)
	$(DIFF) expected_export_coverage.$@.json "$(TMPDIR)"/actual_export_coverage.$@.json
endif