step 1

CMakeLists.txt

@@ -311,6 +311,19 @@ if(CURL_CLANG_TIDY)
   endif()
 endif()
 
+option(CURL_CODE_COVERAGE "Enable code coverage build options" OFF)
+if(CURL_CODE_COVERAGE)
+  set(CURL_CFLAGS_COVERAGE "")
+  set(CURL_LIBS_COVERAGE "")
+  if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
+    string(APPEND CURL_CFLAGS_COVERAGE " -DNDEBUG -O0 -g -fprofile-arcs -ftest-coverage")
+    list(APPEND CURL_LIBS_COVERAGE "gcov")
+  elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
+    string(APPEND CURL_CFLAGS_COVERAGE " -DNDEBUG -O0 -g -fprofile-arcs -ftest-coverage")
+    list(APPEND CURL_LIBS_COVERAGE "llvm-gcov")
+  endif()
+endif()
+
 # For debug libs and exes, add "-d" postfix
 if(NOT DEFINED CMAKE_DEBUG_POSTFIX)
   set(CMAKE_DEBUG_POSTFIX "-d")
@@ -1983,7 +1996,7 @@ if(WIN32)
   endif()
 endif()
 
-list(APPEND CURL_LIBS ${CURL_NETWORK_AND_TIME_LIBS})
+list(APPEND CURL_LIBS ${CURL_NETWORK_AND_TIME_LIBS} ${CURL_LIBS_COVERAGE})
 
 if(CMAKE_C_COMPILER_ID STREQUAL "MSVC")  # MSVC but exclude clang-cl
   set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS "-MP")  # Parallel compilation

docs/INSTALL-CMAKE.md

@@ -229,6 +229,7 @@ target_link_libraries(my_target PRIVATE CURL::libcurl)
 - `BUILD_TESTING`:                          Build tests. Default: `ON`
 - `CURL_CLANG_TIDY`:                        Run the build through `clang-tidy`. Default: `OFF`
 - `CURL_CLANG_TIDYFLAGS`:                   Custom options to pass to `clang-tidy`. Default: (empty)
+- `CURL_CODE_COVERAGE`:                     Enable code coverage build options. Default: `OFF`
 - `CURL_COMPLETION_FISH`:                   Install fish completions. Default: `OFF`
 - `CURL_COMPLETION_FISH_DIR`:               Custom fish completion install directory.
 - `CURL_COMPLETION_ZSH`:                    Install zsh completions. Default: `OFF`

lib/CMakeLists.txt

@@ -25,6 +25,7 @@
 set(LIBCURL_OUTPUT_NAME "${LIB_NAME}" CACHE STRING "Basename of the curl library")
 
 set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS ${CURL_DEBUG_MACROS} "BUILDING_LIBCURL")
+set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS ${CURL_CFLAGS_COVERAGE})
 
 configure_file("curl_config.h.cmake" "${CMAKE_CURRENT_BINARY_DIR}/curl_config.h")
 

src/CMakeLists.txt

@@ -23,6 +23,7 @@
 ###########################################################################
 
 set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS "${CURL_DEBUG_MACROS}")
+set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS ${CURL_CFLAGS_COVERAGE})
 
 set(_curl_cfiles_gen "")
 set(_curl_hfiles_gen "")