Compile posix_libentry into a static library to ensure it's linked last

* If we want our global constructor to run after even static linked
  libaries (which we will soon for LLVM) then we must make it a static
  library as well. We do some tricks to ensure the symbols are still
  pulled in even though it's otherwise "unused".

renderdoc/CMakeLists.txt

@@ -9,25 +9,22 @@ set(RDOC_LIBRARIES)
 
 if(ANDROID)
     list(APPEND RDOC_LIBRARIES
-        PRIVATE m
-        PRIVATE dl
-        PRIVATE log
-        PRIVATE android
-        PRIVATE ${CMAKE_THREAD_LIBS_INIT})
+        PRIVATE -lm
+        PRIVATE -ldl
+        PRIVATE -llog
+        PRIVATE -landroid)
 elseif(APPLE)
     list(APPEND RDOC_LIBRARIES
-        PRIVATE m
-        PRIVATE dl
-        PRIVATE ${CMAKE_THREAD_LIBS_INIT})
+        PRIVATE -lm
+        PRIVATE -ldl)
 elseif(UNIX)
     find_package(PkgConfig REQUIRED)
     find_package(Threads REQUIRED)
 
     list(APPEND RDOC_LIBRARIES
-        PRIVATE m
-        PRIVATE dl
-        PRIVATE rt
-        PRIVATE ${CMAKE_THREAD_LIBS_INIT})
+        PRIVATE -lm
+        PRIVATE -ldl
+        PRIVATE -lrt)
 
     if(ENABLE_XLIB)
         find_package(X11 REQUIRED)
@@ -36,7 +33,7 @@ elseif(UNIX)
             PRIVATE ${X11_X11_INCLUDE_PATH})
 
         list(APPEND RDOC_LIBRARIES
-            PRIVATE ${X11_X11_LIB})
+            PRIVATE -l${X11_X11_LIB})
     endif()
 
     if(ENABLE_XCB)
@@ -49,10 +46,14 @@ elseif(UNIX)
             PRIVATE ${XCB_INCLUDE_DIRS})
 
         list(APPEND RDOC_LIBRARIES
-            PRIVATE ${XCB_LIBRARIES})
+            PRIVATE -l${XCB_LIBRARIES})
     endif()
 endif()
 
+if(NOT "x${CMAKE_THREAD_LIBS_INIT}" STREQUAL "x")
+    list(APPEND RDOC_LIBRARIES PRIVATE -l${CMAKE_THREAD_LIBS_INIT})
+endif()
+
 set(sources
     api/app/renderdoc_app.h
     api/replay/basic_types.h
@@ -218,9 +219,6 @@ if(ANDROID)
         os/posix/posix_stringio.cpp
         os/posix/posix_threading.cpp
         os/posix/posix_specific.h)
-    # posix_libentry must be the last so that library_loaded is called after
-    # static objects are constructed.
-    list(APPEND sources os/posix/posix_libentry.cpp)
 elseif(APPLE)
     list(APPEND sources
         data/embedded_files.h
@@ -237,9 +235,6 @@ elseif(APPLE)
         os/posix/posix_stringio.cpp
         os/posix/posix_threading.cpp
         os/posix/posix_specific.h)
-    # posix_libentry must be the last so that library_loaded is called after
-    # static objects are constructed.
-    list(APPEND sources os/posix/posix_libentry.cpp)
 elseif(UNIX)
     list(APPEND sources
         data/embedded_files.h
@@ -258,9 +253,6 @@ elseif(UNIX)
         os/posix/posix_stringio.cpp
         os/posix/posix_threading.cpp
         os/posix/posix_specific.h)
-    # posix_libentry must be the last so that library_loaded is called after
-    # static objects are constructed.
-    list(APPEND sources os/posix/posix_libentry.cpp)
 endif()
 
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR APPLE)
@@ -281,10 +273,6 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR APPLE)
     endif()
 endif()
 
-add_library(rdoc OBJECT ${sources})
-target_compile_definitions(rdoc ${RDOC_DEFINITIONS})
-target_include_directories(rdoc ${RDOC_INCLUDES})
-
 set(data
     data/glsl/blit.vert
     data/glsl/checkerboard.frag
@@ -371,22 +359,35 @@ endif()
 add_subdirectory(driver/ihv/amd)
 list(APPEND renderdoc_objects $<TARGET_OBJECTS:rdoc_amd>)
 
-# rdoc must be after its drivers because of linux_libentry.cpp
+add_library(rdoc OBJECT ${sources})
+target_compile_definitions(rdoc ${RDOC_DEFINITIONS})
+target_include_directories(rdoc ${RDOC_INCLUDES})
+
 list(APPEND renderdoc_objects
     $<TARGET_OBJECTS:rdoc>
     ${data_objects})
 
+# posix_libentry must be the last so that library_loaded is called after
+# static objects are constructed. We guarantee this happens after even
+# any other static libraries that we link by making it its own static
+# library and appending it to the end of the link list.
+add_library(renderdoc_libentry STATIC os/posix/posix_libentry.cpp)
+target_compile_definitions(renderdoc_libentry ${RDOC_DEFINITIONS})
+target_include_directories(renderdoc_libentry ${RDOC_INCLUDES})
+link_directories(${CMAKE_CURRENT_BINARY_DIR})
+list(APPEND RDOC_LIBRARIES PRIVATE -lrenderdoc_libentry)
+
 add_library(renderdoc SHARED ${renderdoc_objects})
 target_compile_definitions(renderdoc ${RDOC_DEFINITIONS})
 target_include_directories(renderdoc ${RDOC_INCLUDES})
 target_link_libraries(renderdoc ${RDOC_LIBRARIES})
 
 if(UNIX AND NOT ANDROID AND NOT APPLE)
-    set_target_properties(renderdoc PROPERTIES LINK_FLAGS "-Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/renderdoc.version -Wl,--no-undefined")
+    set_target_properties(renderdoc PROPERTIES LINK_FLAGS "-Wl,--undefined,force_include_libentry -Wl,--version-script,${CMAKE_CURRENT_SOURCE_DIR}/renderdoc.version -Wl,--no-undefined")
 endif()
 
 if(ANDROID)
-    set_target_properties(renderdoc PROPERTIES LINK_FLAGS "-Wl,--build-id")
+    set_target_properties(renderdoc PROPERTIES LINK_FLAGS "-Wl,--undefined,force_include_libentry -Wl,--build-id")
     # rename output library
     set_target_properties(renderdoc PROPERTIES OUTPUT_NAME "VkLayer_GLES_RenderDoc")
 

renderdoc/os/posix/posix_libentry.cpp

@@ -87,3 +87,10 @@ struct init
 {
   init() { library_loaded(); }
 } do_init;
+
+// we want to be sure the constructor and library_loaded are included even when this is in a static
+// library, so we have this global function that does nothing but takes the address.
+extern "C" __attribute__((visibility("default"))) void *force_include_libentry()
+{
+  return &do_init;
+}