5 files changed, 51 insertions, 8 deletions
diff --git a/cmake/compiler/clang/settings.cmake b/cmake/compiler/clang/settings.cmake
index 261a55b285f..9a8cb85275e 100644
--- a/cmake/compiler/clang/settings.cmake
+++ b/cmake/compiler/clang/settings.cmake
@@ -18,3 +18,16 @@ endif()
 # -Wno-deprecated-register is needed to suppress 185 gsoap warnings on Unix systems.
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wno-narrowing -Wno-deprecated-register")
 set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG=1")
+
+if (WITH_DYNAMIC_LINKING)
+  # -fPIC is needed to allow static linking in shared libs.
+  # -fvisibility=hidden sets the default visibility to hidden to prevent exporting of all symbols.
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -fvisibility=hidden")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -fvisibility=hidden")
+
+  # --no-undefined to throw errors when there are undefined symbols
+  # (caused through missing TRINITY_*_API macros).
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --no-undefined")
+
+  message(STATUS "Clang: Disallow undefined symbols")
+endif()
diff --git a/cmake/compiler/gcc/settings.cmake b/cmake/compiler/gcc/settings.cmake
index acd71e82fd9..d9eda767b8e 100644
--- a/cmake/compiler/gcc/settings.cmake
+++ b/cmake/compiler/gcc/settings.cmake
@@ -34,3 +34,15 @@ if( WITH_COREDEBUG )
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g3")
   message(STATUS "GCC: Debug-flags set (-g3)")
 endif()
+
+if (WITH_DYNAMIC_LINKING)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -fvisibility=hidden -Wno-attributes")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -fvisibility=hidden -Wno-attributes")
+
+  # Should break the build when there are TRINITY_*_API macros missing
+  # but it complains about missing references in precompiled headers.
+  # set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wl,--no-undefined")
+  # set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wl,--no-undefined")
+
+  message(STATUS "GCC: Enabled shared linking")
+endif()
diff --git a/cmake/compiler/msvc/settings.cmake b/cmake/compiler/msvc/settings.cmake
index 52c19b336cb..86470f327c5 100644
--- a/cmake/compiler/msvc/settings.cmake
+++ b/cmake/compiler/msvc/settings.cmake
@@ -18,11 +18,6 @@ if(PLATFORM EQUAL 64)
   add_definitions("-D_WIN64")
   message(STATUS "MSVC: 64-bit platform, enforced -D_WIN64 parameter")
 
-  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0.23026.0)
-    #Enable extended object support for debug compiles on X64 (not required on X86)
-    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /bigobj")
-    message(STATUS "MSVC: Enabled increased number of sections in object files")
-  endif()
 else()
   # mark 32 bit executables large address aware so they can use > 2GB address space
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /LARGEADDRESSAWARE")
@@ -41,15 +36,20 @@ add_definitions(-D_BUILD_DIRECTIVE=\\"$(ConfigurationName)\\")
 # multithreaded compiling on VS
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
 
+if((PLATFORM EQUAL 64) OR (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0.23026.0) OR WITH_DYNAMIC_LINKING)
+  # Enable extended object support
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /bigobj")
+  message(STATUS "MSVC: Enabled increased number of sections in object files")
+endif()
+
 # /Zc:throwingNew.
 # When you specify Zc:throwingNew on the command line, it instructs the compiler to assume
 # that the program will eventually be linked with a conforming operator new implementation,
 # and can omit all of these extra null checks from your program.
 # http://blogs.msdn.com/b/vcblog/archive/2015/08/06/new-in-vs-2015-zc-throwingnew.aspx
 if(NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0.23026.0))
-  # also enable /bigobj for ALL builds under visual studio 2015, increased number of templates in standard library 
   # makes this flag a requirement to build TC at all
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zc:throwingNew /bigobj")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zc:throwingNew")
 endif()
 
 # Define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES - eliminates the warning by changing the strcpy call to strcpy_s, which prevents buffer overruns
@@ -75,6 +75,13 @@ if(NOT WITH_WARNINGS)
   message(STATUS "MSVC: Disabled generic compiletime warnings")
 endif()
 
+if (WITH_DYNAMIC_LINKING)
+  # C4251: needs to have dll-interface to be used by clients of class '...'
+  # C4275: non dll-interface class ...' used as base for dll-interface class '...'
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4251 /wd4275")
+  message(STATUS "MSVC: Enabled shared linking")
+endif()
+
 # Specify the maximum PreCompiled Header memory allocation limit
 # Fixes a compiler-problem when using PCH - the /Ym flag is adjusted by the compiler in MSVC2012, hence we need to set an upper limit with /Zm to avoid discrepancies)
 # (And yes, this is a verified , unresolved bug with MSVC... *sigh*)
diff --git a/cmake/options.cmake b/cmake/options.cmake
index 6b6a672adc6..1a028959047 100644
--- a/cmake/options.cmake
+++ b/cmake/options.cmake
@@ -13,6 +13,7 @@ option(SCRIPTS          "Build core with scripts included"
 option(TOOLS            "Build map/vmap/mmap extraction/assembler tools"              0)
 option(USE_SCRIPTPCH    "Use precompiled headers when compiling scripts"              1)
 option(USE_COREPCH      "Use precompiled headers when compiling servers"              1)
+option(WITH_DYNAMIC_LINKING "Enable dynamic library linking."                         0)
 option(WITH_WARNINGS    "Show all warnings during compile"                            0)
 option(WITH_COREDEBUG   "Include additional debug-code in core"                       0)
 set(WITH_SOURCE_TREE    "hierarchical" CACHE STRING "Build the source tree for IDE's.")
diff --git a/cmake/showoptions.cmake b/cmake/showoptions.cmake
index b4ef652cf35..b485cfe5ce6 100644
--- a/cmake/showoptions.cmake
+++ b/cmake/showoptions.cmake
@@ -113,5 +113,15 @@ if ( HELGRIND )
   add_definitions(-DHELGRIND)
 endif()
 
-message("")
+if (WITH_DYNAMIC_LINKING)
+  message("")
+  message(" *** WITH_DYNAMIC_LINKING - INFO!")
+  message(" *** Will link against shared libraries!")
+  message(" *** Please note that this is an experimental feature!")
+  add_definitions(-DTRINITY_API_USE_DYNAMIC_LINKING)
+  set(BUILD_SHARED_LIBS ON)
+else()
+  set(BUILD_SHARED_LIBS OFF)
+endif()
 
+message("")