Add coverage build (#560)

Summary:
tl;dr -- our coverage can be better.

Wanted to check out codecov - this is what came of it. Code coverage reports are enabled for the org - add them in CI.
- Codecov is capable of generating super cool reports like flashlight/flashlight#560 (comment) in PR comments, but I've disabled those for now
- View coverage details like https://codecov.io/gh/flashlight/flashlight/tree/17c14502a3c99550e69973e9d0cb1e9374e9ed3e/flashlight
- codecov checks appear in CI which will yell at people if they are landing untested code

Pull Request resolved: flashlight/flashlight#560

Test Plan:
CI

PR comments [disabled for now] like
<img width="1054" alt="Screen Shot 2021-04-22 at 5 55 33 PM" src="https://user-images.githubusercontent.com/7871817/115796168-fa053800-a396-11eb-8d91-8f8b87693b8f.png">

cool visualizations of what we have tests for like
![screencapture-codecov-io-gh-flashlight-flashlight-src-17c14502a3c99550e69973e9d0cb1e9374e9ed3e-flashlight-fl-autograd-Functions-cpp-2021-04-22-17_53_25](https://user-images.githubusercontent.com/7871817/115796181-fe315580-a396-11eb-9dda-fafad249f9de.png)

Reviewed By: tlikhomanenko

Differential Revision: D27954344

Pulled By: jacobkahn

fbshipit-source-id: 30cff2176c97ffdf499fe2bbc41a2feba2b1cb69

.gitignore

@@ -28,3 +28,22 @@ eggs/
 .installed.cfg
 *.egg
 wheels/
+
+# Coverage
+*.info
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib

CMakeLists.txt

@@ -8,13 +8,15 @@ include(CMakeDependentOption)
 # ----------------------------- Setup -----------------------------
 find_program(CCACHE_PROGRAM ccache)
 if(CCACHE_PROGRAM)
-    set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "${CCACHE_PROGRAM}")
+  set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "${CCACHE_PROGRAM}")
 endif()
 
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+option(FL_CODE_COVERAGE "Enable coverage reporting" OFF)
+
 # Default directories for installation
 set(FL_INSTALL_INC_DIR "include" CACHE PATH "Install path for headers")
 set(FL_INSTALL_INC_DIR_HEADER_LOC ${FL_INSTALL_INC_DIR}/flashlight)
@@ -136,6 +138,9 @@ if (FL_BUILD_LIBRARIES OR (FL_BUILD_CORE AND FL_BUILD_TESTS))
   endif ()
 
   setup_install_headers(${FL_LIB_DIR} ${FL_INSTALL_INC_DIR_HEADER_LOC})
+  if (FL_CODE_COVERAGE)
+    add_coverage_to_target(TARGET fl-libraries)
+  endif()
 endif() # if FL_BUILD_LIBRARIES
 
 # --------------------------- flashlight ---------------------------
@@ -157,6 +162,10 @@ if (FL_BUILD_CORE)
     target_link_libraries(flashlight PUBLIC fl-libraries)
   endif()
 
+  if (FL_CODE_COVERAGE)
+    add_coverage_to_target(TARGET flashlight)
+  endif()
+
   # ------------------------ Global External Dependencies ------------------------
   # ArrayFire
   find_package(ArrayFire REQUIRED)

README.md

@@ -11,6 +11,8 @@
 [![Docker Image Build Status](https://img.shields.io/github/workflow/status/flashlight/flashlight/Publish%20Docker%20images?label=docker%20image%20build)](https://hub.docker.com/r/flml/flashlight/tags)
 [![Join the chat at https://gitter.im/flashlight-ml/community](https://img.shields.io/gitter/room/flashlight-ml/community)](https://gitter.im/flashlight-ml/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
+[![codecov](https://codecov.io/gh/flashlight/flashlight/branch/master/graph/badge.svg?token=rBp4AilMc0)](https://codecov.io/gh/flashlight/flashlight)
+
 [![Docker Image for CUDA backend](https://img.shields.io/docker/image-size/flml/flashlight/cuda-latest?label=docker%20%28cuda%29&logo=docker)](https://hub.docker.com/r/flml/flashlight/tags?page=1&ordering=last_updated&name=cuda-latest)
 [![Docker Image for CPU backend](https://img.shields.io/docker/image-size/flml/flashlight/cpu-latest?label=docker%20%28cpu%29&logo=docker)](https://hub.docker.com/r/flml/flashlight/tags?page=1&ordering=last_updated&name=cpu-latest)
 

cmake/InternalUtils.cmake

@@ -1,3 +1,27 @@
+function(add_coverage_to_target)
+  set(oneValueArgs TARGET)
+  cmake_parse_arguments(add_coverage_to_target "${options}" "${oneValueArgs}"
+    "${multiValueArgs}" ${ARGN})
+
+  if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+    # Add required flags (GCC & LLVM/Clang)
+    target_compile_options(${add_coverage_to_target_TARGET} PUBLIC
+      -O0 # TODO: reconcile this with CMake modes for something cleaner
+      -g
+      $<$<COMPILE_LANGUAGE:CXX>:--coverage>
+      )
+    if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.13)
+      target_link_options(${add_coverage_to_target_TARGET}
+        PUBLIC
+        $<$<COMPILE_LANGUAGE:CXX>:--coverage>)
+    else()
+      target_link_libraries(${add_coverage_to_target_TARGET}
+        PUBLIC
+        --coverage)
+    endif()
+  endif()
+endfunction()
+
 function(setup_install_targets)
   set(multiValueArgs INSTALL_TARGETS INSTALL_HEADERS)
   cmake_parse_arguments(setup_install_targets "${options}" "${oneValueArgs}"

codecov.yml

@@ -0,0 +1 @@
+comment: false