Update documentation for coverage tests

Author: Zalathar

src/llvm-coverage-instrumentation.md

@@ -273,20 +273,22 @@ since it will not be called), and adds a new `FunctionCoverage`, with
 
 ## Testing LLVM Coverage
 
-[(See also the compiletest documentation for the `tests/coverage-map` and
-`tests/run-coverage` test suites.)](./tests/compiletest.md#coverage-tests)
+[(See also the compiletest documentation for the `tests/coverage`
+test suite.)](./tests/compiletest.md#coverage-tests)
 
 Coverage instrumentation in the MIR is validated by a `mir-opt` test:
 [`tests/mir-opt/instrument_coverage.rs`].
 
-Coverage instrumentation in LLVM IR is validated by the [`tests/coverage-map`]
-test suite. These tests compile a test program to LLVM IR assembly, and then
+Coverage instrumentation in LLVM IR is validated by the [`tests/coverage`]
+test suite in `coverage-map` mode.
+These tests compile a test program to LLVM IR assembly, and then
 use the [`src/tools/coverage-dump`] tool to extract and pretty-print the
 coverage mappings that would be embedded in the final binary.
 
 End-to-end testing of coverage instrumentation and coverage reporting is
-performed by the [`tests/run-coverage`] and [`tests/run-coverage-rustdoc`]
-test suites. These tests compile and run a test program with coverage
+performed by the [`tests/coverage`] test suite in `coverage-run` mode,
+and by the [`tests/coverage-run-rustdoc`] test suite.
+These tests compile and run a test program with coverage
 instrumentation, then use LLVM tools to convert the coverage data into a
 human-readable coverage report.
 
@@ -296,19 +298,19 @@ expected LLVM IR instructions and structured data for a coverage-enabled
 program, including various checks for Coverage Map-related metadata and the LLVM
 intrinsic calls to increment the runtime counters.
 
-Expected results for the `coverage-map`, `run-coverage`, `run-coverage-rustdoc`,
+Expected results for the `coverage`, `coverage-run-rustdoc`,
 and `mir-opt` tests can be refreshed by running:
 
 ```shell
-./x test tests/*coverage* --bless
+./x test coverage --bless
+./x test coverage-run-rustdoc --bless
 ./x test tests/mir-opt --bless
 ```
 
 [`tests/mir-opt/instrument_coverage.rs`]: https://github.com/rust-lang/rust/blob/master/tests/mir-opt/instrument_coverage.rs
-[`tests/coverage-map`]: https://github.com/rust-lang/rust/tree/master/tests/coverage-map
+[`tests/coverage`]: https://github.com/rust-lang/rust/tree/master/tests/coverage
 [`src/tools/coverage-dump`]: https://github.com/rust-lang/rust/tree/master/src/tools/coverage-dump
-[`tests/run-coverage`]: https://github.com/rust-lang/rust/tree/master/tests/run-coverage
-[`tests/run-coverage-rustdoc`]: https://github.com/rust-lang/rust/tree/master/tests/run-coverage-rustdoc
+[`tests/coverage-run-rustdoc`]: https://github.com/rust-lang/rust/tree/master/tests/coverage-run-rustdoc
 [`coverage-llvmir`]: https://github.com/rust-lang/rust/tree/master/tests/run-make/coverage-llvmir
 
 ## Implementation Details of the `InstrumentCoverage` MIR Pass

src/tests/compiletest.md

@@ -67,11 +67,8 @@ The following test suites are available, with links for more information:
 - `run-make-fulldeps` — `run-make` tests which require a linkable build of `rustc`,
   or the rust demangler
 - [`run-pass-valgrind`](#valgrind-tests) — tests run with Valgrind
-- [`coverage-map`](#coverage-tests) - tests for coverage maps produced by
-  coverage instrumentation
-- [`run-coverage`](#coverage-tests) - tests that run an instrumented program
-  and check its coverage report
-- [`run-coverage-rustdoc`](#coverage-tests) - coverage tests that also run
+- [`coverage`](#coverage-tests) - tests for coverage instrumentation
+- [`coverage-run-rustdoc`](#coverage-tests) - coverage tests that also run
   instrumented doctests
 - [Rustdoc tests](../rustdoc.md#tests):
     - `rustdoc` — tests for rustdoc, making sure that the generated files
@@ -402,7 +399,28 @@ These may be removed in the future.
 
 ### Coverage tests
 
-The tests in [`tests/coverage-map`] test the mappings between source code
+The tests in [`tests/coverage`] are shared by multiple test modes that test
+coverage instrumentation in different ways.
+Running the `coverage` test suite will automatically run each test in all of
+the different coverage modes.
+
+Each mode also has an alias to run the coverage tests in just that mode:
+
+```bash
+./x test coverage # runs all of tests/coverage in all coverage modes
+./x test tests/coverage # same as above
+
+./x test tests/coverage/if.rs # runs the specified test in all coverage modes
+
+./x test coverage-map # runs all of tests/coverage in "coverage-map" mode only
+./x test coverage-run # runs all of tests/coverage in "coverage-run" mode only
+
+./x test coverage-map -- tests/coverage/if.rs # runs the specified test in "coverage-map" mode only
+```
+
+---
+
+In `coverage-map` mode, these tests verify the mappings between source code
 regions and coverage counters that are emitted by LLVM.
 They compile the test with `--emit=llvm-ir`,
 then use a custom tool ([`src/tools/coverage-dump`])
@@ -416,18 +434,18 @@ coverage reports.
 
 As a rule of thumb, any PR that doesn't change coverage-specific
 code should **feel free to re-bless** the `coverage-map` tests as necessary,
-without worrying about the actual changes, as long as the `run-coverage` tests
+without worrying about the actual changes, as long as the `coverage-run` tests
 still pass.
 
 ---
 
-The tests in [`tests/run-coverage`] perform an end-to-end test of coverage reporting.
+In `coverage-run` mode, these tests perform an end-to-end test of coverage reporting.
 They compile a test program with coverage instrumentation, run that program to
 produce raw coverage data, and then use LLVM tools to process that data into a
 human-readable code coverage report.
 
 Instrumented binaries need to be linked against the LLVM profiler runtime,
-so `run-coverage` tests are **automatically skipped**
+so `coverage-run` tests are **automatically skipped**
 unless the profiler runtime is enabled in `config.toml`:
 
 ```toml
@@ -439,14 +457,15 @@ profiler = true
 This also means that they typically don't run in PR CI jobs,
 though they do run as part of the full set of CI jobs used for merging.
 
-The tests in [`tests/run-coverage-rustdoc`] also run instrumented doctests and
+---
+
+The tests in [`tests/coverage-run-rustdoc`] also run instrumented doctests and
 include them in the coverage report. This avoids having to build rustdoc when
-only running the main `run-coverage` suite.
+only running the main `coverage` suite.
 
-[`tests/coverage-map`]: https://github.com/rust-lang/rust/tree/master/tests/coverage-map
+[`tests/coverage`]: https://github.com/rust-lang/rust/tree/master/tests/coverage
 [`src/tools/coverage-dump`]: https://github.com/rust-lang/rust/tree/master/src/tools/coverage-dump
-[`tests/run-coverage`]: https://github.com/rust-lang/rust/tree/master/tests/run-coverage
-[`tests/run-coverage-rustdoc`]: https://github.com/rust-lang/rust/tree/master/tests/run-coverage-rustdoc
+[`tests/coverage-run-rustdoc`]: https://github.com/rust-lang/rust/tree/master/tests/coverage-run-rustdoc
 
 
 ## Building auxiliary crates