diff --git a/docs/OWNERS b/docs/OWNERS
index d143317..45ec523 100644
--- a/docs/OWNERS
+++ b/docs/OWNERS
@@ -1 +1,2 @@
 per-file map_files.md = danalbert@google.com, enh@google.com, jiyong@google.com
+per-file native_code_coverage.md = pirama@google.com, srhines@google.com, allenhair@google.com
diff --git a/docs/native_code_coverage.md b/docs/native_code_coverage.md
new file mode 100644
index 0000000..fabbfa0
--- /dev/null
+++ b/docs/native_code_coverage.md
@@ -0,0 +1,241 @@
+## Native Code Coverage for Android
+
+## Scope
+
+These instructions are for Android developers to collect and inspect code
+coverage for C++ and Rust code on the Android platform.
+
+## Building with Native Code Coverage Instrumentation
+
+Identify the paths where native code-coverage instrumentation should be enabled
+and set up the following environment variables.
+
+```
+    export CLANG_COVERAGE=true
+    export NATIVE_COVERAGE_PATHS="<paths-to-instrument-for-coverage>"
+```
+
+`NATIVE_COVERAGE_PATHS` should be a list of paths. Any Android.bp module defined
+under these paths is instrumented for code-coverage. E.g:
+
+```
+export NATIVE_COVERAGE_PATHS="external/libcxx system/core/adb"
+```
+
+### Additional Notes
+
+-   Native Code coverage is not supported for host modules or `Android.mk`
+    modules.
+-   `NATIVE_COVERAGE_PATHS="*"` enables coverage instrumentation for all paths.
+-   Set `native_coverage: false` blueprint property to always disable code
+    coverage instrumentation for a module. This is useful if this module has
+    issues when building or running with coverage.
+-   `NATIVE_COVERAGE_EXCLUDE_PATHS` can be set to exclude subdirs under
+    `NATIVE_COVERAGE_PATHS` from coverage instrumentation. E.g.
+    `NATIVE_COVERAGE_PATHS=frameworks/native
+    NATIVE_COVERAGE_PATHS=frameworks/native/vulkan` will instrument all native
+    code under `frameworks/native` except`frameworks/native/vulkan`.
+
+## Running Tests
+
+### Collecting Profiles
+
+When an instrumented program is run, the profiles are stored to the path and
+name specified in the `LLVM_PROFILE_FILE` environment variable. On Android
+coverage builds it is set to `/data/misc/trace/clang-%p-%20m.profraw`.
+
+*   `%`p is replaced by the pid of the process
+*   `%m` by the hash of the library/binary
+*   The `20` in`%20m` creates a pool of 20 profraw files and "online" profile
+    merging is used to merge coverage to profiles onto this pool.
+
+Reference:`LLVM_PROFILE_FILE` can include additional specifiers as described
+[here](https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#running-the-instrumented-program).
+
+For this and following steps, use the `acov-llvm.py` script:
+`$ANDROID_BUILD_TOP/development/scripts/acov-llvm.py`.
+
+There may be profiles in `/data/misc/trace` collected before the test is run.
+Clear this data before running the test.
+
+```
+    # Clear any coverage that's already written to /data/misc/trace
+    # and reset coverage for all daemons.
+    <host>$ acov-llvm.py clean-device
+
+    # Run the test.  The exact command depends on the nature of the test.
+    <device>$ /data/local/tmp/$MY_TEST
+```
+
+For tests that exercise a daemon/service running in another process, write out
+the coverage for those processes as well.
+
+```
+    # Flush coverage of all daemons/processes running on the device.
+    <host>$ acov-llvm.py flush
+
+    # Flush coverage for a particular daemon, say adbd.
+    <host>$ acov-llvm.py flush adbd
+```
+
+## Viewing Coverage Data (acov-llvm.py)
+
+To post-process and view coverage information we use the `acov-llvm.py report`
+command. It invokes two LLVM utilities `llvm-profdata` and `llvm-cov`. An
+advanced user can manually invoke these utilities for fine-grained control. This
+is discussed [below](#viewing-coverage-data-manual).
+
+To generate coverage report need the following parameters. These are dependent
+on the test/module:
+
+1.  One or more binaries and shared libraries from which coverage was collected.
+    E.g.:
+
+    1.  ART mainline module contains a few libraries such as `libart.so`,
+        `libart-compiler.so`.
+    2.  Bionic tests exercise code in `libc.so` and `libm.so`.
+
+    We need the *unstripped* copies of these binaries. Source information
+    included in the debuginfo is used to process the coverage data.
+
+2.  One or more source directories under `$ANDROID_BUILD_TOP` for which coverage
+    needs to be reported.
+
+Invoke the report subcommand of acov-llvm.py to produce a html coverage summary:
+
+```
+    $ acov-llvm.py report \
+        -s <one-or-more-source-paths-in-$ANDROID_BUILD_TOP \
+        -b <one-or-more-(unstripped)-binaries-in-$OUT>
+```
+
+E.g.:
+
+```
+    $ acov-llvm.py report \
+        -s bionic \
+        -b \
+        $OUT/symbols/apex/com.android.runtime/lib/bionic/libc.so \
+        $OUT/symbols/apex/com.android.runtime/lib/bionic/libm.so
+```
+
+The script will produce a report in a temporary directory under
+`$ANDROID_BUILD_TOP`. It'll produce a log as below:
+
+```
+    generating coverage report in covreport-xxxxxx
+```
+
+A html report would be generated under `covreport-xxxxxx/html`.
+
+## Viewing Coverage Data (manual)
+
+`acov-llvm.py report` does a few operations under the hood which we can also
+manually invoke for flexibility.
+
+### Post-processing Coverage Files
+
+Fetch coverage files from the device and post-process them to a `.profdata` file
+as follows:
+
+```
+    # Fetch the coverage data from the device.
+    <host>$ cd coverage_data
+    <host>$ adb pull /data/misc/trace/ $TRACE_DIR_HOST
+
+    # Convert from .profraw format to the .profdata format.
+    <host>$ llvm-profdata merge --output=$MY_TEST.profdata \
+    $TRACE_DIR_HOST/clang-*.profraw
+```
+
+For added specificity, restrict the above command to just the <PID>s of the
+daemon or test processes of interest.
+
+```
+    <host>$ llvm-profdata merge --output=$MY_TEST.profdata \
+    $MY_TEST.profraw \
+    trace/clang-<pid1>.profraw trace/clang-<pid2>.profraw ...
+```
+
+### Generating Coverage report
+
+Documentation on Clang source-instrumentation-based coverage is available
+[here](https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#creating-coverage-reports).
+The `llvm-cov` utility is used to show coverage from a `.profdata` file. The
+documentation for commonly used `llvm-cov` command-line arguments is available
+[here](https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-report). (Try
+`llvm-cov show --help` for a complete list).
+
+#### `show` subcommand
+
+The `show` command displays the function and line coverage for each source file
+in the binary.
+
+```
+    <host>$ llvm-cov show \
+        --show-region-summary=false
+        --format=html --output-dir=coverage-html \
+        --instr-profile=$MY_TEST.profdata \
+        $MY_BIN \
+```
+
+*   In the above command, `$MY_BIN` should be the unstripped binary (i.e. with
+    debuginfo) since `llvm-cov` reads some debuginfo to process the coverage
+    data.
+
+    E.g.:
+
+    ~~~
+    ```
+    <host>$ llvm-cov report \
+        --instr-profile=adbd.profdata \
+        $LOCATION_OF_UNSTRIPPED_ADBD/adbd \
+        --show-region-summary=false
+    ```
+    ~~~
+
+*   The `-ignore-filename-regex=<regex>` option can be used to ignore files that
+    are not of interest. E.g: `-ignore-filename-regex="external/*"`
+
+*   Use the `--object=<BIN>` argument to specify additional binaries and shared
+    libraries whose coverage is included in this profdata. See the earlier
+    [section](#viewing-coverage-data-acov-llvm-py) for examples where more than
+    one binary may need to be used.
+
+    E.g., the following command is used for `bionic-unit-tests`, which tests
+    both `libc.so` and `libm.so`:
+
+    ~~~
+    ```
+    <host>$ llvm-cov report \
+        --instr-profile=bionic.profdata \
+        $OUT/.../libc.so \
+        --object=$OUT/.../libm.so
+    ```
+    ~~~
+
+*   `llvm-cov` also takes positional SOURCES argument to consider/display only
+    particular paths of interest. E.g:
+
+    ~~~
+    ```
+    <host>$ llvm-cov report \
+        --instr-profile=adbd.profdata \
+        $LOCATION_OF_ADBD/adbd \
+        --show-region-summary=false \
+        /proc/self/cwd/system/core/adb
+    ```
+    ~~~
+
+Note that the paths for the sources need to be prepended with
+'`/proc/self/cwd/`'. This is because Android C/C++ compilations run with
+`PWD=/proc/self/cwd` and consequently the source names are recorded with that
+prefix. Alternatively, the
+[`--path-equivalence`](https://llvm.org/docs/CommandGuide/llvm-cov.html#cmdoption-llvm-cov-show-path-equivalence)
+option to `llvm-cov` can be used.
+
+#### `report` subcommand
+
+The [`report`](https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-report)
+subcommand summarizes the percentage of covered lines to the console. It takes
+options similar to the `show` subcommand.