1 # needs-profiler-support
4 # Rust coverage maps support LLVM Coverage Mapping Format versions 5 and 6,
5 # corresponding with LLVM versions 12 and 13, respectively.
6 # When upgrading LLVM versions, consider whether to enforce a minimum LLVM
7 # version during testing, with an additional directive at the top of this file
8 # that sets, for example: `min-llvm-version: 12.0`
10 # FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
11 # properly. Since we only have GCC on the CI ignore the test for now.
13 -include ../coverage/coverage_tools.mk
15 BASEDIR=../coverage-reports
18 # The `llvm-cov show` flag `--debug`, used to generate the `counters` output files, is only
19 # enabled if LLVM assertions are enabled. This requires Rust config `llvm/optimize` and not
20 # `llvm/release_debuginfo`. Note that some CI builds disable debug assertions (by setting
21 # `NO_LLVM_ASSERTIONS=1`), so the tests must still pass even if the `--debug` flag is
22 # not supported. (Note that `counters` files are only produced in the `$(TMPDIR)`
23 # directory, for inspection and debugging support. They are *not* copied to `expected_*`
24 # files when `--bless`ed.)
25 LLVM_COV_DEBUG := $(shell \
26 "$(LLVM_BIN_DIR)"/llvm-cov show --debug 2>&1 | \
27 grep -q "Unknown command line argument '--debug'"; \
29 ifeq ($(LLVM_COV_DEBUG), 1)
33 # FIXME(richkadel): I'm adding `--ignore-filename-regex=` line(s) for specific test(s) that produce
34 # `llvm-cov` results for multiple files (for example `uses_crate.rs` and `used_crate/mod.rs`) as a
35 # workaround for two problems causing tests to fail on Windows:
37 # 1. When multiple files appear in the `llvm-cov show` results, each file's coverage results can
38 # appear in different a different order. Whether this is random or, somehow, platform-specific,
39 # the Windows output flips the order of the files, compared to Linux. In the `uses_crate.rs`
40 # test, the only test-unique (interesting) results we care about are the results for only one
41 # of the two files, `mod/uses_crate.rs`, so the workaround is to ignore all but this one file.
42 # In the future, we may want a more sophisticated solution that splits apart `llvm-cov show`
43 # results into separate results files for each result (taking care not to create new file
44 # paths that might be too long for Windows MAX_PATH limits when creating these new sub-results,
46 # 2. When multiple files appear in the `llvm-cov show` results, the results for each file are
47 # prefixed with their filename, including platform-specific path separators (`\` for Windows,
48 # and `/` everywhere else). This could be filtered or normalized of course, but by ignoring
49 # coverage results for all but one of the file, the filenames are no longer included anyway.
50 # If this changes (if/when we decide to support `llvm-cov show` results for multiple files),
51 # the file path separator differences may need to be addressed.
53 # Since this is only a workaround, I decided to implement the override by adding an option for
54 # each file to be ignored, using a `--ignore-filename-regex=` entry for each one, rather than
55 # implement some more sophisticated solution with a new custom test directive in the test file
56 # itself (similar to `expect-exit-status`) because that would add a lot of complexity and still
57 # be a workaround, with the same result, with no benefit.
59 # Yes these `--ignore-filename-regex=` options are included in all invocations of `llvm-cov show`
60 # for now, but it is effectively ignored for all tests that don't include this file anyway.
62 # (Note that it's also possible the `_counters.<test>.txt` and `<test>.json` files (if generated)
63 # may order results from multiple files inconsistently, which might also have to be accomodated
64 # if and when we allow `llvm-cov` to produce results for multiple files. Note, the path separators
65 # appear to be normalized to `/` in those files, thankfully.)
66 LLVM_COV_IGNORE_FILES=\
67 --ignore-filename-regex='(uses_crate.rs|uses_inline_crate.rs|unused_mod.rs)'
69 all: $(patsubst $(SOURCEDIR)/lib/%.rs,%,$(wildcard $(SOURCEDIR)/lib/*.rs)) $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))
71 # Ensure there are no `expected` results for tests that may have been removed or renamed
72 .PHONY: clear_expected_if_blessed
73 clear_expected_if_blessed:
74 ifdef RUSTC_BLESS_TEST
78 -include clear_expected_if_blessed
80 %: $(SOURCEDIR)/lib/%.rs
81 # Compile the test library with coverage instrumentation
82 $(RUSTC) $(SOURCEDIR)/lib/$@.rs \
83 $$( sed -n 's/^\/\/ compile-flags: \([^#]*\).*/\1/p' $(SOURCEDIR)/lib/$@.rs ) \
84 --crate-type rlib -Cinstrument-coverage
87 # Compile the test program with coverage instrumentation
88 $(RUSTC) $(SOURCEDIR)/$@.rs \
89 $$( sed -n 's/^\/\/ compile-flags: \([^#]*\).*/\1/p' $(SOURCEDIR)/$@.rs ) \
90 -L "$(TMPDIR)" -Cinstrument-coverage
92 # Run it in order to generate some profiling data,
93 # with `LLVM_PROFILE_FILE=<profdata_file>` environment variable set to
94 # output the coverage stats for this run.
95 LLVM_PROFILE_FILE="$(TMPDIR)"/$@.profraw \
99 grep -q "^\/\/ expect-exit-status-$$status" $(SOURCEDIR)/$@.rs || \
100 ( >&2 echo "program exited with an unexpected exit status: $$status"; \
105 # Run it through rustdoc as well to cover doctests.
106 # `%p` is the pid, and `%m` the binary signature. We suspect that the pid alone
107 # might result in overwritten files and failed tests, as rustdoc spawns each
108 # doctest as its own process, so make sure the filename is as unique as possible.
109 LLVM_PROFILE_FILE="$(TMPDIR)"/$@-%p-%m.profraw \
110 $(RUSTDOC) --crate-name workaround_for_79771 --test $(SOURCEDIR)/$@.rs \
111 $$( sed -n 's/^\/\/ compile-flags: \([^#]*\).*/\1/p' $(SOURCEDIR)/$@.rs ) \
112 -L "$(TMPDIR)" -Cinstrument-coverage \
113 -Z unstable-options --persist-doctests=$(TMPDIR)/rustdoc-$@
115 # Postprocess the profiling data so it can be used by the llvm-cov tool
116 "$(LLVM_BIN_DIR)"/llvm-profdata merge --sparse \
117 "$(TMPDIR)"/$@*.profraw \
118 -o "$(TMPDIR)"/$@.profdata
120 # Generate a coverage report using `llvm-cov show`.
121 "$(LLVM_BIN_DIR)"/llvm-cov show \
123 $(LLVM_COV_IGNORE_FILES) \
124 --compilation-dir=. \
125 --Xdemangler="$(RUST_DEMANGLER)" \
126 --show-line-counts-or-regions \
127 --instr-profile="$(TMPDIR)"/$@.profdata \
128 $(call BIN,"$(TMPDIR)"/$@) \
130 for file in $(TMPDIR)/rustdoc-$@/*/rust_out; do \
131 [ -x "$$file" ] && printf "%s %s " -object $$file; \
134 2> "$(TMPDIR)"/show_coverage_stderr.$@.txt \
135 | "$(PYTHON)" $(BASEDIR)/normalize_paths.py \
136 > "$(TMPDIR)"/actual_show_coverage.$@.txt || \
138 >&2 cat "$(TMPDIR)"/show_coverage_stderr.$@.txt ; \
143 # The first line (beginning with "Args:" contains hard-coded, build-specific
144 # file paths. Strip that line and keep the remaining lines with counter debug
146 tail -n +2 "$(TMPDIR)"/show_coverage_stderr.$@.txt \
147 > "$(TMPDIR)"/actual_show_coverage_counters.$@.txt
150 ifdef RUSTC_BLESS_TEST
151 cp "$(TMPDIR)"/actual_show_coverage.$@.txt \
152 expected_show_coverage.$@.txt
154 # Compare the show coverage output (`--bless` refreshes `typical` files).
156 # FIXME(richkadel): None of the Rust test source samples have the
157 # `// ignore-llvm-cov-show-diffs` anymore. This directive exists to work around a limitation
158 # with `llvm-cov show`. When reporting coverage for multiple instantiations of a generic function,
159 # with different type substitutions, `llvm-cov show` prints these in a non-deterministic order,
160 # breaking the `diff` comparision.
162 # A partial workaround is implemented below, with `diff --ignore-matching-lines=RE`
163 # to ignore each line prefixing each generic instantiation coverage code region.
165 # This workaround only works if the coverage counts are identical across all reported
166 # instantiations. If there is no way to ensure this, you may need to apply the
167 # `// ignore-llvm-cov-show-diffs` directive, and check for differences using the
168 # `.json` files to validate that results have not changed. (Until then, the JSON
169 # files are redundant, so there is no need to generate `expected_*.json` files or
170 # compare actual JSON results.)
172 $(DIFF) --ignore-matching-lines='^ | .*::<.*>.*:$$' --ignore-matching-lines='^ | <.*>::.*:$$' \
173 expected_show_coverage.$@.txt "$(TMPDIR)"/actual_show_coverage.$@.txt || \
174 ( grep -q '^\/\/ ignore-llvm-cov-show-diffs' $(SOURCEDIR)/$@.rs && \
175 >&2 echo 'diff failed, but suppressed with `// ignore-llvm-cov-show-diffs` in $(SOURCEDIR)/$@.rs' \
177 ( >&2 echo 'diff failed, and not suppressed without `// ignore-llvm-cov-show-diffs` in $(SOURCEDIR)/$@.rs'; \