Toolchain+LibC: Fix usage of crt files

We now configure the gcc spec files to use a different crt files for
static & PIE binaries.

This relieves us from the need to explicitly specify the desired crt0
file in cmake scripts.

CMakeLists.txt

@@ -113,7 +113,7 @@ add_compile_options(-ffile-prefix-map=${CMAKE_SOURCE_DIR}=.)
 
 add_compile_definitions(DEBUG SANITIZE_PTRS)
 set(CMAKE_CXX_FLAGS_STATIC "${CMAKE_CXX_FLAGS} -static")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostartfiles -pie -fpic")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pie -fpic")
  
 add_link_options(--sysroot ${CMAKE_BINARY_DIR}/Root)
 

Demos/DynamicObject/CMakeLists.txt

@@ -1,6 +1,5 @@
 set(SOURCES
     main.cpp
-    ../../Libraries/LibC/crt0_shared.cpp
 )
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostartfiles -lgcc_s -pie -fpic ")

Libraries/LibC/CMakeLists.txt

@@ -1,7 +1,6 @@
 set(LIBC_SOURCES
     arpa/inet.cpp
     assert.cpp
-    crt0_shared.cpp
     ctype.cpp
     cxxabi.cpp
     dirent.cpp
@@ -64,6 +63,11 @@ add_custom_command(
     TARGET crt0
     COMMAND ${INSTALL_COMMAND} -D $<TARGET_OBJECTS:crt0> ${CMAKE_INSTALL_PREFIX}/usr/lib/crt0.o
 )
+add_library(crt0_shared STATIC crt0_shared.cpp)
+add_custom_command(
+    TARGET crt0_shared
+    COMMAND ${INSTALL_COMMAND} -D $<TARGET_OBJECTS:crt0_shared> ${CMAKE_INSTALL_PREFIX}/usr/lib/crt0_shared.o
+)
 
 set(SOURCES ${LIBC_SOURCES} ${AK_SOURCES} ${ELF_SOURCES})
 

Libraries/LibELF/DynamicLoader.cpp

@@ -327,17 +327,32 @@ void DynamicLoader::do_relocations(size_t total_tls_size)
         }
         case R_386_GLOB_DAT: {
             auto symbol = relocation.symbol();
-            if (!strcmp(symbol.name(), "__deregister_frame_info") || !strcmp(symbol.name(), "_ITM_registerTMCloneTable")
-                || !strcmp(symbol.name(), "_ITM_deregisterTMCloneTable") || !strcmp(symbol.name(), "__register_frame_info")
-                || !strcmp(symbol.name(), "__cxa_finalize") // __cxa_finalize will be called from libc's exit()
-            ) {
-                // We do not support these
-                break;
-            }
             VERBOSE("Global data relocation: '%s', value: %p\n", symbol.name(), symbol.value());
             auto res = lookup_symbol(symbol);
+            if (!res.found) {
+                // We do not support these
+                // TODO: Can we tell gcc not to generate the piece of code that uses these?
+                // (--disable-tm-clone-registry flag in gcc conifugraion?)
+                if (!strcmp(symbol.name(), "__deregister_frame_info") || !strcmp(symbol.name(), "_ITM_registerTMCloneTable")
+                    || !strcmp(symbol.name(), "_ITM_deregisterTMCloneTable") || !strcmp(symbol.name(), "__register_frame_info")) {
+                    break;
+                }
+
+                // The "__do_global_dtors_aux" function in libgcc_s.so needs this symbol,
+                // but we do not use that function so we don't actually need to resolve this symbol.
+                // The reason we can't resolve it here is that the symbol is defined in libc.so,
+                // but there's a circular dependecy between libgcc_s.so and libc.so,
+                // we deal with it by first loading libgcc_s and then libc.
+                // So we cannot find this symbol at this time (libc is not yet loaded).
+                if (m_filename == "libgcc_s.so" && !strcmp(symbol.name(), "__cxa_finalize")) {
+                    break;
+                }
+
+                // Symbol not found
+                ASSERT_NOT_REACHED();
+            }
             VERBOSE("was symbol found? %d, address: 0x%x\n", res.found, res.address);
-            ASSERT(res.found);
+            VERBOSE("object: %s\n", m_filename.characters());
 
             if (!res.found) {
                 // TODO this is a hack

Meta/CMake/utils.cmake

@@ -28,8 +28,7 @@ function(serenity_lib target_name fs_name)
     serenity_install_headers(${target_name})
     serenity_install_sources("Libraries/${target_name}")
     #add_library(${target_name} SHARED ${SOURCES} ${GENERATED_SOURCES})
-    add_library(${target_name} SHARED ${SOURCES} ${GENERATED_SOURCES} ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
-    #library_sources("{target_name}" PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
+    add_library(${target_name} SHARED ${SOURCES} ${GENERATED_SOURCES})
     install(TARGETS ${target_name} DESTINATION usr/lib)
     set_target_properties(${target_name} PROPERTIES OUTPUT_NAME ${fs_name})
     serenity_generated_sources(${target_name})
@@ -67,7 +66,6 @@ endfunction()
 
 function(serenity_bin target_name)
     add_executable(${target_name} ${SOURCES})
-    target_sources(${target_name} PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
     install(TARGETS ${target_name} RUNTIME DESTINATION bin)
     serenity_generated_sources(${target_name})
 endfunction()

Toolchain/Patches/gcc.patch

@@ -115,7 +115,7 @@ diff -ruN a/gcc/config/serenity.h b/gcc/config/serenity.h
 +/* Files that are linked before user code.
 +   The %s tells GCC to look for these files in the library directory. */
 +#undef STARTFILE_SPEC
-+#define STARTFILE_SPEC "%{!shared:crt0.o%s} crti.o%s %{shared|pie:crtbeginS.o%s; :crtbegin.o%s}"
++#define STARTFILE_SPEC "%{static:crt0.o%s} crti.o%s %{!static: %{!fbuilding-libgcc:crt0_shared.o%s}} %{shared|pie:crtbeginS.o%s; :crtbegin.o%s}"
 +
 +/* Files that are linked after user code. */
 +#undef ENDFILE_SPEC

Userland/CMakeLists.txt

@@ -5,13 +5,11 @@ foreach(CMD_SRC ${CMD_SOURCES})
     get_filename_component(CMD_NAME ${CMD_SRC} NAME_WE)
     if (CMD_NAME IN_LIST SPECIAL_TARGETS)
         add_executable("${CMD_NAME}-bin" ${CMD_SRC})
-        target_sources("${CMD_NAME}-bin" PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
         target_link_libraries("${CMD_NAME}-bin" LibCore)
         install(TARGETS "${CMD_NAME}-bin" RUNTIME DESTINATION bin)
         install(CODE "execute_process(COMMAND mv ${CMD_NAME}-bin ${CMD_NAME} WORKING_DIRECTORY ${CMAKE_INSTALL_PREFIX}/bin)")
     else ()
         add_executable(${CMD_NAME} ${CMD_SRC})
-        target_sources("${CMD_NAME}" PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
         target_link_libraries(${CMD_NAME} LibCore)
         install(TARGETS ${CMD_NAME} RUNTIME DESTINATION bin)
     endif()

Userland/Tests/Kernel/CMakeLists.txt

@@ -3,7 +3,6 @@ file(GLOB CMD_SOURCES CONFIGURE_DEPENDS "*.cpp")
 foreach(CMD_SRC ${CMD_SOURCES})
     get_filename_component(CMD_NAME ${CMD_SRC} NAME_WE)
     add_executable(${CMD_NAME} ${CMD_SRC})
-    target_sources("${CMD_NAME}" PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
     target_link_libraries(${CMD_NAME} LibCore)
     install(TARGETS ${CMD_NAME} RUNTIME DESTINATION usr/Tests/Kernel)
 endforeach()

Userland/Tests/LibC/CMakeLists.txt

@@ -3,7 +3,6 @@ file(GLOB CMD_SOURCES  CONFIGURE_DEPENDS "*.cpp")
 foreach(CMD_SRC ${CMD_SOURCES})
     get_filename_component(CMD_NAME ${CMD_SRC} NAME_WE)
     add_executable(${CMD_NAME} ${CMD_SRC})
-    target_sources("${CMD_NAME}" PRIVATE ${CMAKE_SOURCE_DIR}/Libraries/LibC/crt0_shared.cpp)
     target_link_libraries(${CMD_NAME} LibCore)
     install(TARGETS ${CMD_NAME} RUNTIME DESTINATION usr/Tests/LibC)
 endforeach()