make git build info work with submodules

CMakeLists.txt

@@ -76,23 +76,31 @@ option(LLAMA_BUILD_EXAMPLES         "llama: build examples" ${LLAMA_STANDALONE})
 # Build info header
 #
 
-# Write header template to binary dir to keep source directory clean
-file(WRITE "${CMAKE_BINARY_DIR}/BUILD_INFO.h.in" "\
-#ifndef BUILD_INFO_H\n\
-#define BUILD_INFO_H\n\
-\n\
-#define BUILD_NUMBER @BUILD_NUMBER@\n\
-#define BUILD_COMMIT \"@BUILD_COMMIT@\"\n\
-\n\
-#endif // BUILD_INFO_H\n\
-")
-
 # Generate initial build-info.h
 include(${CMAKE_CURRENT_SOURCE_DIR}/scripts/build-info.cmake)
 
 if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git")
+    set(GIT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/.git")
+
+    # Is git submodule
+    if(NOT IS_DIRECTORY "${GIT_DIR}")
+        file(READ ${GIT_DIR} REAL_GIT_DIR_LINK)
+        string(REGEX REPLACE "gitdir: (.*)\n$" "\\1" REAL_GIT_DIR ${REAL_GIT_DIR_LINK})
+        set(GIT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/${REAL_GIT_DIR}")
+    endif()
+
     # Add a custom target for build-info.h
     add_custom_target(BUILD_INFO ALL DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/build-info.h")
+
+    # Add a custom command to rebuild build-info.h when .git/index changes
+    add_custom_command(
+        OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/build-info.h"
+        COMMENT "Generating build details from Git"
+        COMMAND ${CMAKE_COMMAND} -P "${CMAKE_CURRENT_SOURCE_DIR}/scripts/build-info.cmake"
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+        DEPENDS "${GIT_DIR}/index"
+        VERBATIM
+    )
 else()
     message(WARNING "Git repository not found; to enable automatic generation of build info, make sure Git is installed and the project is a Git repository.")
 endif()

scripts/build-info.cmake

@@ -1,4 +1,4 @@
-set(TEMPLATE_FILE "${CMAKE_BINARY_DIR}/BUILD_INFO.h.in")
+set(TEMPLATE_FILE "${CMAKE_CURRENT_SOURCE_DIR}/scripts/build-info.h.in")
 set(HEADER_FILE "${CMAKE_CURRENT_SOURCE_DIR}/build-info.h")
 set(BUILD_NUMBER 0)
 set(BUILD_COMMIT "unknown")

scripts/build-info.h.in

@@ -0,0 +1,7 @@
+#ifndef BUILD_INFO_H
+#define BUILD_INFO_H
+
+#define BUILD_NUMBER @BUILD_NUMBER@
+#define BUILD_COMMIT "@BUILD_COMMIT@"
+
+#endif // BUILD_INFO_H