CMake: Automatic regeneration of the library dependencies file.

It doesn't stop or reconfigure the build, though, so the user will see
a broken build that magically succeeds at the next attempt. It is
technically possible to halt the build with a helpful message, and
even to automatically restart the build using the new dependencies as
it we did when llvm-config was used by cmake for learning
dependencies. This is left on the TODO list.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79004 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 49 insertions, 26 deletions

diff --git a/cmake/modules/LLVMConfig.cmake b/cmake/modules/LLVMConfig.cmake
index 4a05e32b2a..1d8d090986 100755
--- a/cmake/modules/LLVMConfig.cmake
+++ b/cmake/modules/LLVMConfig.cmake
@@ -1,5 +1,3 @@
-include(LLVMLibDeps)
-
 function(get_system_libs return_var)
   # Returns in `return_var' a list of system libraries used by LLVM.
   if( NOT MSVC )
@@ -101,3 +99,29 @@ function(explicit_map_components_to_libraries out_libs)
   endwhile( 0 LESS ${lst_size} )
   set(${out_libs} ${result} PARENT_SCOPE)
 endfunction(explicit_map_components_to_libraries)
+
+
+# The library dependency data is contained in the file
+# LLVMLibDeps.cmake on this directory. It is automatically generated
+# by tools/llvm-config/CMakeLists.txt when the build comprises all the
+# targets and we are on a environment Posix enough to build the
+# llvm-config script. This, in practice, just excludes MSVC.
+
+# When you remove or rename a library from the build, be sure to
+# remove its file from lib/ as well, or the GenLibDeps.pl script will
+# include it on its analysis!
+
+# The format generated by GenLibDeps.pl
+
+# LLVMARMAsmPrinter.o: LLVMARMCodeGen.o libLLVMAsmPrinter.a libLLVMCodeGen.a libLLVMCore.a libLLVMSupport.a libLLVMTarget.a
+
+# is translated to:
+
+# set(MSVC_LIB_DEPS_LLVMARMAsmPrinter LLVMARMCodeGen LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMSupport LLVMTarget)
+
+# It is necessary to remove the `lib' prefix and the `.a'.
+
+# This 'sed' script should do the trick:
+# sed -e s'#\.a##g' -e 's#libLLVM#LLVM#g' -e 's#: # #' -e 's#\(.*\)#set(MSVC_LIB_DEPS_\1)#' ~/llvm/tools/llvm-config/LibDeps.txt
+
+include(LLVMLibDeps)
diff --git a/cmake/modules/LLVMLibDeps.cmake b/cmake/modules/LLVMLibDeps.cmake
index 5271f86dd0..c13e3cb79b 100644
--- a/cmake/modules/LLVMLibDeps.cmake
+++ b/cmake/modules/LLVMLibDeps.cmake
@@ -1,26 +1,3 @@
-# This data is used to establish executable/library
-# dependencies.  Comes from the llvm-config script, which is built and
-# installed on the bin directory for MinGW or Linux. At the end of the
-# script, you'll see lines like this:
-
-# LLVMARMAsmPrinter.o: LLVMARMCodeGen.o libLLVMAsmPrinter.a libLLVMCodeGen.a libLLVMCore.a libLLVMSupport.a libLLVMTarget.a
-
-# This is translated to:
-
-# set(MSVC_LIB_DEPS_LLVMARMAsmPrinter LLVMARMCodeGen LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMSupport LLVMTarget)
-
-# It is necessary to remove the `lib' prefix and the `.a'.
-
-# This 'sed' script should do the trick:
-# sed -e s'#\.a##g' -e 's#libLLVM#LLVM#g' -e 's#: # #' -e 's#\(.*\)#set(MSVC_LIB_DEPS_\1)#' ~/llvm/tools/llvm-config/LibDeps.txt
-#
-
-# TODO: do this transformations on cmake.
-
-# It is very important that the LLVM built for extracting this data
-# must contain all targets, not just X86.
-
-
 set(MSVC_LIB_DEPS_LLVMARMAsmPrinter LLVMARMCodeGen LLVMARMInfo LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMSupport LLVMSystem LLVMTarget)
 set(MSVC_LIB_DEPS_LLVMARMCodeGen LLVMARMInfo LLVMCodeGen LLVMCore LLVMSelectionDAG LLVMSupport LLVMSystem LLVMTarget)
 set(MSVC_LIB_DEPS_LLVMARMInfo LLVMSupport)
@@ -79,7 +56,7 @@ set(MSVC_LIB_DEPS_LLVMSystemZInfo LLVMSupport)
 set(MSVC_LIB_DEPS_LLVMTarget LLVMCore LLVMMC LLVMSupport LLVMSystem)
 set(MSVC_LIB_DEPS_LLVMTransformUtils LLVMAnalysis LLVMCore LLVMSupport LLVMSystem LLVMTarget LLVMipa)
 set(MSVC_LIB_DEPS_LLVMX86AsmParser LLVMMC LLVMX86Info)
-set(MSVC_LIB_DEPS_LLVMX86AsmPrinter LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMSupport LLVMSystem LLVMTarget LLVMX86CodeGen LLVMX86Info)
+set(MSVC_LIB_DEPS_LLVMX86AsmPrinter LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMMC LLVMSupport LLVMSystem LLVMTarget LLVMX86CodeGen LLVMX86Info)
 set(MSVC_LIB_DEPS_LLVMX86CodeGen LLVMCodeGen LLVMCore LLVMSelectionDAG LLVMSupport LLVMSystem LLVMTarget LLVMX86Info)
 set(MSVC_LIB_DEPS_LLVMX86Info LLVMSupport)
 set(MSVC_LIB_DEPS_LLVMXCore LLVMAsmPrinter LLVMCodeGen LLVMCore LLVMSelectionDAG LLVMSupport LLVMSystem LLVMTarget LLVMXCoreInfo)
diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt
index 4873794635..b029663011 100644
--- a/tools/llvm-config/CMakeLists.txt
+++ b/tools/llvm-config/CMakeLists.txt
@@ -124,4 +124,26 @@ install(FILES ${LLVM_CONFIG}
   WORLD_READ WORLD_EXECUTE
   DESTINATION bin)
 
+
+# Regeneration of library dependencies.
+
+# See the comments at the end of cmake/modules/LLVMConfig.cmake for
+# notes and guidelines.
+
+set(LLVMLibDeps ${LLVM_MAIN_SRC_DIR}/cmake/modules/LLVMLibDeps.cmake)
+set(LLVMLibDeps_TMP ${CMAKE_CURRENT_BINARY_DIR}/LLVMLibDeps.cmake.tmp)
+
+add_custom_command(OUTPUT ${LLVMLibDeps_TMP}
+  COMMAND sed -e s'@\\.a@@g' -e 's@libLLVM@LLVM@g' -e 's@: @ @' -e 's@\\\(.*\\\)@set\(MSVC_LIB_DEPS_\\1\)@' ${FINAL_LIBDEPS} > ${LLVMLibDeps_TMP}
+  COMMAND ${CMAKE_COMMAND} -E copy_if_different ${LLVMLibDeps_TMP} ${LLVMLibDeps}
+  DEPENDS ${FINAL_LIBDEPS}
+  COMMENT "Updating cmake library dependencies file ${LLVMLibDeps}"
+  )
+
+if( LLVM_TARGETS_TO_BUILD STREQUAL LLVM_ALL_TARGETS )
+  add_custom_target(llvmlibdeps.target ALL DEPENDS ${LLVMLibDeps_TMP})
+  add_dependencies(llvmlibdeps.target llvm-config.target)
+  set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} llvmlibdeps.target)
+endif()
+
 set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS} PARENT_SCOPE)