Disallow in-source builds

[jroelofs]

Summary

Context: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150323/268067.html

[reames]

This is very unlikely to ever be accepted. In particular, I know of
several long standing developers who use in tree builds.

Do you have a good *reason* (other than merely best practice) why this
needs to be changed?

Philip

[echristo]

Hi Philip:

A stream of comments :)

We've started warning recently, it is best practice, we don't want to worry about breaking it, the bots have all been updated, and I don't know any of the long standing developers who use this that we haven't spoken to - who were you thinking of precisely?

-eric

[echristo]

Oh, and I was planning on stamping it as I was the one that had requested it so now is a good time to throw an objection if you have one. :)

-eric

[reames]

@nick - If you want to preserve in tree builds, here's you chance.

[echristo]

We have spoken to Nick. :)

[jroelofs]

@reames: you mean @kledzik? @nlewycky already gave a thumbs up in the aforementioned thread: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150323/268067.html

Anyone else?

[reames]

I withdraw all objection.

[echristo]

Sorry for the delay, I thought I'd ack'd this. LGTM and thanks!

-eric

[jroelofs]

r241178

Makefile.config.in

 PROJ_SRC_ROOT   := $(LLVM_SRC_ROOT)
 PROJ_SRC_DIR    := $(LLVM_SRC_ROOT)$(patsubst $(PROJ_OBJ_ROOT)%,%,$(PROJ_OBJ_DIR))
 
-# FIXME: This is temporary during the grace period where in-source builds are
-# deprecated. Convert to a hard error when that period is up.
-#
 # See: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150323/268067.html
 ifeq ($(LLVM_SRC_ROOT), $(LLVM_OBJ_ROOT))
-  $(warning ######################################################################################)
-  $(warning #                                                                                    #)
-  $(warning #                                   WARNING                                          #)
-  $(warning #                                                                                    #)
-  $(warning #                        In-source builds are deprecated.                            #)
-  $(warning #                                                                                    #)
-  $(warning #               Please configure from a separate build directory!                    #)
-  $(warning #                                                                                    #)
-  $(warning ######################################################################################)
+  $(error In-source builds are not allowed. Please configure from a separate build directory!)
 endif
 
 ifneq ($(CLANG_SRC_ROOT),)

autoconf/configure.ac

 
 dnl Quit if it is an in-source build
 if test ${srcdir} == "." ; then
-  AC_MSG_WARN([**************************************************************************************])
-  AC_MSG_WARN([*                                                                                    *])
-  AC_MSG_WARN([*                                   WARNING                                          *])
-  AC_MSG_WARN([*                                                                                    *])
-  AC_MSG_WARN([*                        In-source builds are deprecated.                            *])
-  AC_MSG_WARN([*                                                                                    *])
-  AC_MSG_WARN([*               Please configure from a separate build directory!                    *])
-  AC_MSG_WARN([*                                                                                    *])
-  AC_MSG_WARN([**************************************************************************************])
+  AC_MSG_ERROR([In-source builds are not allowed. Please configure from a separate build directory!])
 fi
 
 dnl Default to empty (i.e. assigning the null string to) CFLAGS and CXXFLAGS,

configure

 fi
 
 if test ${srcdir} == "." ; then
-  { echo "$as_me:$LINENO: WARNING: **************************************************************************************" >&5
-echo "$as_me: WARNING: **************************************************************************************" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                                                                                    *" >&5
-echo "$as_me: WARNING: *                                                                                    *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                                   WARNING                                          *" >&5
-echo "$as_me: WARNING: *                                   WARNING                                          *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                                                                                    *" >&5
-echo "$as_me: WARNING: *                                                                                    *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                        In-source builds are deprecated.                            *" >&5
-echo "$as_me: WARNING: *                        In-source builds are deprecated.                            *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                                                                                    *" >&5
-echo "$as_me: WARNING: *                                                                                    *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *               Please configure from a separate build directory!                    *" >&5
-echo "$as_me: WARNING: *               Please configure from a separate build directory!                    *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: *                                                                                    *" >&5
-echo "$as_me: WARNING: *                                                                                    *" >&2;}
-  { echo "$as_me:$LINENO: WARNING: **************************************************************************************" >&5
-echo "$as_me: WARNING: **************************************************************************************" >&2;}
+  { { echo "$as_me:$LINENO: error: In-source builds are not allowed. Please configure from a separate build directory!" >&5
+echo "$as_me: error: In-source builds are not allowed. Please configure from a separate build directory!" >&2;}
+   { (exit 1); exit 1; }; }
 fi
 
 : ${CFLAGS=}