Revise the docs for coverage instrumentation tests

src/llvm-coverage-instrumentation.md

@@ -274,32 +274,42 @@ 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)
+
 Coverage instrumentation in the MIR is validated by a `mir-opt` test:
-[`instrument-coverage`][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
+use the [`src/tools/coverage-dump`] tool to extract and pretty-print the
+coverage mappings that would be embedded in the final binary.
 
-More complete testing of end-to-end coverage instrumentation and reports are
-done in the `run-make-fulldeps` tests, with sample Rust programs (to be
-instrumented) in the [`tests/run-coverage`] directory,
-together with the actual tests and expected results.
+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
+instrumentation, then use LLVM tools to convert the coverage data into a
+human-readable coverage report.
 
 Finally, the [`coverage-llvmir`] test compiles a simple Rust program
 with `-C instrument-coverage` and compares the compiled program's LLVM IR to
 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 both the `mir-opt` tests and the `coverage*` tests
-can be refreshed by running:
+Expected results for the `coverage-map`, `run-coverage`, `run-coverage-rustdoc`,
+and `mir-opt` tests can be refreshed by running:
 
 ```shell
+./x test tests/*coverage* --bless
 ./x test tests/mir-opt --bless
-./x test tests/run-coverage --bless
-./x test tests/run-coverage-rustdoc --bless
 ```
 
-[mir-opt-test]: https://github.com/rust-lang/rust/blob/master/tests/mir-opt/instrument_coverage.rs
+[`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
+[`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
-[spanview-debugging]: compiler-debugging.md#viewing-spanview-output
+[`tests/run-coverage-rustdoc`]: https://github.com/rust-lang/rust/tree/master/tests/run-coverage-rustdoc
 [`coverage-llvmir`]: https://github.com/rust-lang/rust/tree/master/tests/run-make/coverage-llvmir
 
 ## Implementation Details of the `InstrumentCoverage` MIR Pass