build: add Source Link to embed GitHub source mappings in PDBs

Author: Ben Hillis

CMakeLists.txt

@@ -156,6 +156,10 @@ file(MAKE_DIRECTORY ${BIN})
 set (GENERATED_DIR ${CMAKE_BINARY_DIR}/generated)
 file(MAKE_DIRECTORY ${GENERATED_DIR})
 
+# Generate Source Link JSON so debuggers can fetch source from GitHub
+set(SOURCELINK_JSON "${GENERATED_DIR}/sourcelink.json")
+file(WRITE "${SOURCELINK_JSON}" "{\"documents\":{\"${CMAKE_SOURCE_DIR}/*\":\"https://raw.githubusercontent.com/microsoft/WSL/${COMMIT_HASH}/*\"}}")
+
 set(PACKAGE_CERTIFICATE ${GENERATED_DIR}/dev-cert.pfx)
 file(CREATE_LINK ${WSL_DEVICE_HOST_SOURCE_DIR}/bin/${TARGET_PLATFORM}/wsldevicehost.dll ${BIN}/wsldevicehost.dll)
 file(CREATE_LINK ${WSLG_SOURCE_DIR}/${TARGET_PLATFORM}/${WSLG_TS_PLUGIN_DLL} ${BIN}/${WSLG_TS_PLUGIN_DLL})
@@ -232,6 +236,8 @@ set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Zi /guard:cf /Qspectre"
 # Linker flags
 set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /debug:full /debugtype:cv,fixup /guard:cf /DYNAMICBASE")
 set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /debug:full /debugtype:cv,fixup /guard:cf /DYNAMICBASE")
+set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} /SOURCELINK:${SOURCELINK_JSON}")
+set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /SOURCELINK:${SOURCELINK_JSON}")
 if (${TARGET_PLATFORM} STREQUAL "x64")
     set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /CETCOMPAT")
     set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /CETCOMPAT")