[cmake-developers] [CMake 0015678]: CMakeCache.txt can't be passed into cmake's -C flag

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
====================================================================== 
http://public.kitware.com/Bug/view.php?id=15678 
====================================================================== 
Reported By:                Chris
Assigned To:                
====================================================================== 
Project:                    CMake
Issue ID:                   15678
Category:                   CMake
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
====================================================================== 
Date Submitted:             2015-08-03 17:08 EDT
Last Modified:              2015-08-03 17:08 EDT
====================================================================== 
Summary:                    CMakeCache.txt can't be passed into cmake's -C flag
Description: 
I'm probably trying to be too clever, but I'm trying to setup a cmake build
target for clang to do a "bootstrap" build where you build clang, then use the
built clang to rebuild clang. I had this "genius" idea that I could try and pass
through the CMake options used to configure the first clang using the
CMakeCache.txt and the -C flag. It unfortunately doesn't work. I see the
following errors:

[2/5] Performing configure step for 'bootstrap'
FAILED: cd
/Users/cbieneman/dev/open-source/llvm-build-rel/tools/clang/bootstrap/src/bootstrap-build
&& /Users/cbieneman/dev/open-source/cmake-bins/bin/cmake -C
/Users/cbieneman/dev/open-source/llvm-build-rel/CMakeCache.txt
-DCMAKE_CXX_COMPILER=/Users/cbieneman/dev/open-source/llvm-build-rel/bin/clang++
-DCMAKE_CXX_COMPILER=/Users/cbieneman/dev/open-source/llvm-build-rel/bin/clang
"-GSublime Text 2 - Ninja" /Users/cbieneman/dev/open-source/llvm &&
/Users/cbieneman/dev/open-source/cmake-bins/bin/cmake -E touch
/Users/cbieneman/dev/open-source/llvm-build-rel/tools/clang/bootstrap/src/bootstrap-stamp/bootstrap-configure
loading initial cache file
/Users/cbieneman/dev/open-source/llvm-build-rel/CMakeCache.txt
CMake Error: Error in cmake code at
/Users/cbieneman/dev/open-source/llvm-build-rel/CMakeCache.txt:17:
Parse error.  Expected a command name, got unquoted argument with text
"//Default".
CMake Error: Error processing file:
/Users/cbieneman/dev/open-source/llvm-build-rel/CMakeCache.txt

Steps to Reproduce: 
Apply the diffs below to clang, and configure with CMake setting
-DCLANG_ENABLE_BOOTSTRAP=On, and run <buildtool> bootstrap.

Additional Information: 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab70f1d..6974b6e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -96,6 +96,7 @@ if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
 
   option(LLVM_FORCE_USE_OLD_HOST_TOOLCHAIN
     "Set to ON to force using an old, unsupported host toolchain." OFF)
+  option(CLANG_ENABLE_BOOTSTRAP "Generate the clang bootstrap target" OFF)
 
   include(AddLLVM)
   include(TableGen)
@@ -551,3 +552,31 @@ if (CLANG_BUILT_STANDALONE)
     ${CLANG_BINARY_DIR}/share/clang/cmake/ClangConfig.cmake
     COPYONLY)
 endif ()
+
+if (CLANG_ENABLE_BOOTSTRAP)
+  include(ExternalProject)
+
+  ExternalProject_Add(bootstrap
+    DEPENDS clang
+    PREFIX bootstrap
+    SOURCE_DIR ${CMAKE_SOURCE_DIR}
+    CMAKE_ARGS -C ${CMAKE_BINARY_DIR}/CMakeCache.txt
+                ${CLANG_BOOTSTRAP_CMAKE_ARGS}
+                -DCMAKE_CXX_COMPILER=${CMAKE_BINARY_DIR}/bin/clang++
+                -DCMAKE_CXX_COMPILER=${CMAKE_BINARY_DIR}/bin/clang
+    STEP_TARGETS configure build
+    )
+  
+  ExternalProject_Add_Step(bootstrap force-reconfigure
+    DEPENDERS configure
+    ALWAYS 1
+    )
+
+  ExternalProject_Add_Step(bootstrap clobber
+    COMMAND ${CMAKE_COMMAND} -E remove_directory <BINARY_DIR>
+    COMMAND ${CMAKE_COMMAND} -E make_directory <BINARY_DIR>
+    COMMENT "Clobberring compiler-rt build directory..."
+    DEPENDERS configure
+    DEPENDS ${LLVM_RUNTIME_OUTPUT_INTDIR}/bootstrap
+  )
+endif()

====================================================================== 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2015-08-03 17:08 Chris          New Issue                                    
======================================================================