[PATCH v3 1/2] UnitTestFrameworkPkg: Add code coverage support for GCC

["Guo, Gua" <gua.guo@intel.com>]

From: Gua Guo <gua.guo@intel.com>

In order to collect code coverage after running executable
file, generate *.gcda and *.gcno file that require by lcov tool
to generate code coverage report.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Cc: Michael Kubacki <mikuback@linux.microsoft.com>
Signed-off-by: Gua Guo <gua.guo@intel.com>
---
 UnitTestFrameworkPkg/ReadMe.md                | 42 +++++++++++++++++--
 .../UnitTestFrameworkPkg.ci.yaml              |  2 +
 .../UnitTestFrameworkPkgHost.dsc.inc          |  3 +-
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/UnitTestFrameworkPkg/ReadMe.md b/UnitTestFrameworkPkg/ReadMe.md
index e696412cb3..3c69cfdd97 100644
--- a/UnitTestFrameworkPkg/ReadMe.md
+++ b/UnitTestFrameworkPkg/ReadMe.md
@@ -60,7 +60,7 @@ you should be good to go.
 
 See this example in 'SampleUnitTestUefiShell.inf'...
 
-```
+```inf
 [Packages]
   MdePkg/MdePkg.dec
 
@@ -75,7 +75,7 @@ See this example in 'SampleUnitTestUefiShell.inf'...
 Also, if you want you test to automatically be picked up by the Test Runner plugin, you will need
 to make sure that the module `BASE_NAME` contains the word `Test`...
 
-```
+```inf
 [Defines]
   BASE_NAME      = SampleUnitTestUefiShell
 ```
@@ -361,7 +361,7 @@ RUNNING TEST SUITE: Int Safe Conversions Test Suite
 ```
 
 You can also, if you are so inclined, read the output from the exact instance of the test that was run during
-`stuart_ci_build`. The ouput file can be found on a path that looks like:
+`stuart_ci_build`. The output file can be found on a path that looks like:
 
 `Build/<Package>/HostTest/<Arch>/<TestName>.<TestSuiteName>.<Arch>.result.xml`
 
@@ -399,6 +399,42 @@ CMOCKA_XML_FILE=<absolute or relative path to output file>
 
 This mode is used by the test running plugin to aggregate the results for CI test status reporting in the web view.
 
+### Code Coverage
+
+Host based Unit Tests will automatically i enable coverage data.
+This is primarily leveraged for pipeline builds, but this can be leveraged locally using the
+lcov linux tool, and parsed using the lcov_cobertura python tool. pycobertura is used to
+covert this coverage data to a human readable HTML file. These tools must be installed
+to parse code coverage.
+
+- Windows Prerequisite
+  ```bash
+  Download and install https://github.com/OpenCppCoverage/OpenCppCoverage/tags
+  pip install pycobertura
+  ```
+
+- Linux Prerequisite
+  ```bash
+  sudo apt-get install -y lcov
+  pip install lcov_cobertura
+  pip install pycobertura
+  ```
+
+During CI builds, use the  ```CODE_COVERAGE=TRUE``` flag to generate the code coverage XML files,
+and additionally use the ```CC_HTML=TRUE``` flag to generate the HTML file. This will be generated
+in Build/coverage.html.
+
+There is currently no official guidance or support for code coverage when compiling
+in Visual Studio at this time.
+During CI builds, use the  ```CODE_COVERAGE=TRUE``` flag to generate the code coverage XML files,
+and additionally use the ```CC_HTML=TRUE``` flag to generate the HTML file. This will be generated
+in Build/coverage.html.
+
+Example
+```bash
+  stuart_ci_build -c .pytool/CISettings.py  -t NOOPT TOOL_CHAIN_TAG=VS2019 -p MdeModulePkg CC_HTML=TRUE CODE_COVERAGE=TRUE
+ ```
+
 ### Important Note
 
 This works on both Windows and Linux, but is currently limited to x64 architectures. Working on getting others, but we
diff --git a/UnitTestFrameworkPkg/UnitTestFrameworkPkg.ci.yaml b/UnitTestFrameworkPkg/UnitTestFrameworkPkg.ci.yaml
index 77d51e1348..f68882e1cf 100644
--- a/UnitTestFrameworkPkg/UnitTestFrameworkPkg.ci.yaml
+++ b/UnitTestFrameworkPkg/UnitTestFrameworkPkg.ci.yaml
@@ -90,6 +90,8 @@
             "pytools",
             "NOFAILURE",
             "cmockery",
+            "cobertura",
+            "pycobertura",
             "DHAVE", # build flag for cmocka in the INF
             "corthon",      # Contact GitHub account in Readme
             "mdkinney",     # Contact GitHub account in Readme
diff --git a/UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc b/UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc
index 4dd8d4ac67..ca46b8513a 100644
--- a/UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc
+++ b/UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc
@@ -25,7 +25,8 @@
   GCC:*_*_*_CC_FLAGS   = -D UNIT_TESTING_DEBUG=1
   XCODE:*_*_*_CC_FLAGS = -D UNIT_TESTING_DEBUG=1
 !endif
-
+  GCC:*_GCC5_*_CC_FLAGS = --coverage
+  GCC:*_GCC5_*_DLINK_FLAGS = --coverage
 [BuildOptions.common.EDKII.HOST_APPLICATION]
   #
   # MSFT
-- 
2.31.1.windows.1