[CMake] Generate LLDB_REVISION at build time

[beanz]

Summary

This alters the generation of LLDB_REVISION to be heavily based on how clang generates its version header. There are two benefits of this aproach.

(1) The LLDB_REVISION is generated at build time, so it will be updated after an SCM pull/update even if CMake doesn't re-run
(2) This works on Windows

As noted this code is a simplified implementation of the code from clang.

[zturner]

Should this be sunk into a common llvm function instead of copying from clang? I don't have a strong opinion, but are you one of the main CMake maintainers in LLVM, so whatever you think is best.

[beanz]

Putting this in LLVM would be ideal, but I think doing that requires a larger refactoring of how LLVM and Clang handle SCM versions. I was kinda hoping to land this and fix the lldb support, but if you'd prefer I can shelve this until after fixing LLVM & Clang.

[tfiala]

Looks good.

I think it's fine landing here for now based on your earlier comments about the refactoring effort to get it into LLVM/clang. I do think it's worth trying to sink it lower when the time is right to do more of that refactoring, though.

Thanks!

[zturner]

lgtm, everything works.

source/CMakeLists.txt

DEPENDS ${LLDB_SOURCE_DIR}/scripts/generate-vers.pl
             ${LLDB_SOURCE_DIR}/lldb.xcodeproj/project.pbxproj)
   set_source_files_properties(${LLDB_VERS_GENERATED_FILE} PROPERTIES GENERATED 1)
   # Add this to lldbBase since lldb.cpp uses the symbol defined here.
   list(APPEND lldbBase_SOURCES ${LLDB_VERS_GENERATED_FILE})
   add_custom_target(lldbGeneratedVersion
     DEPENDS ${LLDB_VERS_GENERATED_FILE})
 endif()
 
+foreach(file
+        "${LLDB_SOURCE_DIR}/.git/logs/HEAD" # Git
+        "${LLDB_SOURCE_DIR}/.svn/wc.db"     # SVN 1.7
+        "${LLDB_SOURCE_DIR}/.svn/entries"   # SVN 1.6
+        )
+  if(EXISTS "${file}")
+    set(lldb_vc "${file}")
+    break()
+  endif()
+endforeach()
+
+if(DEFINED lldb_vc)
+  set(version_inc "${CMAKE_CURRENT_BINARY_DIR}/SVNVersion.inc")
+  set(get_svn_script "${LLVM_MAIN_SRC_DIR}/cmake/modules/GetSVN.cmake")
+
+  # Create custom target to generate the VC revision include.
+  add_custom_command(OUTPUT "${version_inc}"
+    DEPENDS "${lldb_vc}" "${get_svn_script}"
+    COMMAND
+    ${CMAKE_COMMAND} "-DFIRST_SOURCE_DIR=${LLDB_SOURCE_DIR}"
+                     "-DFIRST_NAME=LLDB"
+                     "-DHEADER_FILE=${version_inc}"
+                     -P "${get_svn_script}")
+
+  # Mark the generated header as being generated.
+  set_source_files_properties("${version_inc}"
+    PROPERTIES GENERATED TRUE
+               HEADER_FILE_ONLY TRUE)
+
+  # Tell Version.cpp that it needs to build with -DHAVE_SVN_VERSION_INC.
+  set_source_files_properties(lldb.cpp
+    PROPERTIES COMPILE_DEFINITIONS "HAVE_SVN_VERSION_INC")
+  list(APPEND lldbBase_SOURCES ${version_inc})
+endif()
+
 add_lldb_library(lldbBase
   ${lldbBase_SOURCES}
   )
 
 if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
   add_dependencies(lldbBase lldbGeneratedVersion)
 endif()
 
 add_subdirectory(Breakpoint)
 add_subdirectory(Commands)
 add_subdirectory(Core)
 add_subdirectory(DataFormatters)
 add_subdirectory(Expression)
 add_subdirectory(Host)
 add_subdirectory(Initialization)
 add_subdirectory(Interpreter)
 add_subdirectory(Plugins)
 add_subdirectory(Symbol)
 add_subdirectory(Target)
 add_subdirectory(Utility)
 
 # Build API last.  Since liblldb needs to link against every other target, it needs
 # those targets to have already been created.
 add_subdirectory(API)
-
-# Determine LLDB revision and repository. GetSourceVersion and GetRepositoryPath are shell-scripts, and as
-# such will not work on Windows.
-if ( NOT CMAKE_SYSTEM_NAME MATCHES "Windows" )
-  execute_process(COMMAND ${CMAKE_SOURCE_DIR}/utils/GetSourceVersion ${LLDB_SOURCE_DIR}
-                  OUTPUT_VARIABLE LLDB_REVISION)
-  if ( LLDB_REVISION )
-    string(REGEX REPLACE "(\r?\n)+$" "" LLDB_REVISION ${LLDB_REVISION})
-  endif()
-
-  execute_process(COMMAND ${CMAKE_SOURCE_DIR}/utils/GetRepositoryPath ${LLDB_SOURCE_DIR}
-                  OUTPUT_VARIABLE LLDB_REPOSITORY)
-  if ( LLDB_REPOSITORY )
-    # Replace newline characters with spaces
-    string(REGEX REPLACE "(\r?\n)+" " " LLDB_REPOSITORY ${LLDB_REPOSITORY})
-
-    # Remove trailing spaces
-    string(REGEX REPLACE "(\ )+$" "" LLDB_REPOSITORY ${LLDB_REPOSITORY})
-  endif()
-
-  set_property(
-    SOURCE lldb.cpp
-    PROPERTY COMPILE_DEFINITIONS "LLDB_REVISION=\"${LLDB_REVISION}\"" "LLDB_REPOSITORY=\"${LLDB_REPOSITORY}\"")
-endif ()
-# FIXME: implement svn/git revision and repository parsing solution on Windows. There is an SVN-only
-#        revision parsing solution in tools/clang/lib/Basic/CMakelists.txt.

source/lldb.cpp

 using namespace lldb_private;
 
 #if defined(__APPLE__)
 extern "C" const unsigned char liblldb_coreVersionString[];
 #else
 
 #include "clang/Basic/Version.h"
 
+#ifdef HAVE_SVN_VERSION_INC
+#  include "SVNVersion.inc"
+#endif
+
 static const char *GetLLDBRevision() {
 #ifdef LLDB_REVISION
   return LLDB_REVISION;
 #else
   return NULL;
 #endif
 }