Re: [Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Emil Velikov]

On 15 April 2016 at 00:30, Tim Rowley  wrote:

> --- a/src/gallium/drivers/swr/Makefile.am
> +++ b/src/gallium/drivers/swr/Makefile.am
> @@ -22,7 +22,7 @@
>  include Makefile.sources
>  include $(top_srcdir)/src/gallium/Automake.inc
>
> -AM_CXXFLAGS = $(GALLIUM_DRIVER_CFLAGS)
> +AM_CXXFLAGS = $(GALLIUM_DRIVER_CFLAGS) -std=c++11
>
>  noinst_LTLIBRARIES = libmesaswr.la
>
> @@ -31,6 +31,7 @@ libmesaswr_la_SOURCES = $(LOADER_SOURCES)
>  COMMON_CXXFLAGS = \
> $(GALLIUM_DRIVER_CFLAGS) \
> $(LLVM_CFLAGS) \
> +   -std=c++11 \

As others have pointed out things will go interesting as we get
miss-match between LLVM and SWR. But let's worry about that when we
get there.

Reviewed-by: Emil Velikov 

-Emil
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Re: [Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Ilia Mirkin]

On Fri, Apr 15, 2016 at 12:10 PM, Chuck Atkins  wrote:
>> > As LLVM_CXXFLAGS / `llvm-config --cxxflags` already includes std=c++11
>>
>> Yes, I saw that and considered going that direction, but wasn’t sure if we
>> should rely on llvm setting the language version required.
>
>
> Shouldn't you do both? Use LLVM_CXXFLAGS since swr is C++ code including and
> using the LLVM C++ API.  Add stc=c++11 since swr itself is using C++ 11
> features, regardless of llvm's requirements.  This way, each piece is
> defining it's own requirements.  Just relying on LLVM_CXXFLGS is essentially
> assuming that LLVM knows how swr needs to be built.  :-/ .  The end result
> may be a duplicate std=c++11 entry but it's really more coincidence.  LLVM
> could decide that they want to abandon C++11 and not use it (I know,
> extremely unlikely) but swr would still need it regardless.

Should be fun when LLVM decides to move to c++14 :)

Tim, thanks a lot for taking care of this -- I'm no expert on the mesa
build system, so I'll let others do the actual review bit of it.

  -ilia
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Re: [Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Chuck Atkins]

>
> > As LLVM_CXXFLAGS / `llvm-config --cxxflags` already includes std=c++11
>
> Yes, I saw that and considered going that direction, but wasn’t sure if we
> should rely on llvm setting the language version required.
>

Shouldn't you do both? Use LLVM_CXXFLAGS since swr is C++ code including
and using the LLVM C++ API.  Add stc=c++11 since swr itself is using C++ 11
features, regardless of llvm's requirements.  This way, each piece is
defining it's own requirements.  Just relying on LLVM_CXXFLGS is
essentially assuming that LLVM knows how swr needs to be built.  :-/ .  The
end result may be a duplicate std=c++11 entry but it's really more
coincidence.  LLVM could decide that they want to abandon C++11 and not use
it (I know, extremely unlikely) but swr would still need it regardless.
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Re: [Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Rowley, Timothy O]

> On Apr 15, 2016, at 10:33 AM, Jose Fonseca  wrote:
> 
> On 15/04/16 00:30, Tim Rowley wrote:
>> On the philosophy that a driver shouldn't change the compile flags
>> for the entire tree, take the clove approach of moving the c++11 flag
>> to the swr driver directory.
>> ---
>>  configure.ac|   9 +-
>>  m4/ax_cxx_compile_stdcxx.m4 | 558 
>> 
>>  src/gallium/drivers/swr/Makefile.am |   3 +-
>>  3 files changed, 9 insertions(+), 561 deletions(-)
>>  delete mode 100644 m4/ax_cxx_compile_stdcxx.m4
>> 
>> diff --git a/configure.ac b/configure.ac
>> index 8c82c43..6155942 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -2265,15 +2265,20 @@ if test -n "$with_gallium_drivers"; then
>>  fi
>>  ;;
>>  xswr)
>> -AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
>>  swr_llvm_check "swr"
>> 
>> -AC_MSG_CHECKING([whether $CXX supports AVX/AVX2])
>> +AC_MSG_CHECKING([whether $CXX supports c++11/AVX/AVX2])
>>  AVX_CXXFLAGS="-march=core-avx-i"
>>  AVX2_CXXFLAGS="-march=core-avx2"
>> 
>>  AC_LANG_PUSH([C++])
>>  save_CXXFLAGS="$CXXFLAGS"
>> +CXXFLAGS="-std=c++11 $CXXFLAGS"
>> +AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
>> +  [AC_MSG_ERROR([c++11 compiler support not 
>> detected])])
>> +CXXFLAGS="$save_CXXFLAGS"
>> +
>> +save_CXXFLAGS="$CXXFLAGS"
>>  CXXFLAGS="$AVX_CXXFLAGS $CXXFLAGS"
>>  AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
>>[AC_MSG_ERROR([AVX compiler support not 
>> detected])])
>> diff --git a/m4/ax_cxx_compile_stdcxx.m4 b/m4/ax_cxx_compile_stdcxx.m4
>> deleted file mode 100644
>> index 079e17d..000
>> --- a/m4/ax_cxx_compile_stdcxx.m4
>> +++ /dev/null
>> @@ -1,558 +0,0 @@
>> -# 
>> ===
>> -#   http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
>> -# 
>> ===
>> -#
>> -# SYNOPSIS
>> -#
>> -#   AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
>> -#
>> -# DESCRIPTION
>> -#
>> -#   Check for baseline language coverage in the compiler for the specified
>> -#   version of the C++ standard.  If necessary, add switches to CXXFLAGS to
>> -#   enable support.  VERSION may be '11' (for the C++11 standard) or '14'
>> -#   (for the C++14 standard).
>> -#
>> -#   The second argument, if specified, indicates whether you insist on an
>> -#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
>> -#   -std=c++11).  If neither is specified, you get whatever works, with
>> -#   preference for an extended mode.
>> -#
>> -#   The third argument, if specified 'mandatory' or if left unspecified,
>> -#   indicates that baseline support for the specified C++ standard is
>> -#   required and that the macro should error out if no mode with that
>> -#   support is found.  If specified 'optional', then configuration proceeds
>> -#   regardless, after defining HAVE_CXX${VERSION} if and only if a
>> -#   supporting mode is found.
>> -#
>> -# LICENSE
>> -#
>> -#   Copyright (c) 2008 Benjamin Kosnik 
>> -#   Copyright (c) 2012 Zack Weinberg 
>> -#   Copyright (c) 2013 Roy Stogner 
>> -#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov 
>> 
>> -#   Copyright (c) 2015 Paul Norman 
>> -#   Copyright (c) 2015 Moritz Klammler 
>> -#
>> -#   Copying and distribution of this file, with or without modification, are
>> -#   permitted in any medium without royalty provided the copyright notice
>> -#   and this notice are preserved.  This file is offered as-is, without any
>> -#   warranty.
>> -
>> -#serial 1
>> -
>> -dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
>> -dnl  (serial version number 13).
>> -
>> -AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
>> -  m4_if([$1], [11], [],
>> -[$1], [14], [],
>> -[$1], [17], [m4_fatal([support for C++17 not yet implemented in 
>> AX_CXX_COMPILE_STDCXX])],
>> -[m4_fatal([invalid first argument `$1' to 
>> AX_CXX_COMPILE_STDCXX])])dnl
>> -  m4_if([$2], [], [],
>> -[$2], [ext], [],
>> -[$2], [noext], [],
>> -[m4_fatal([invalid second argument `$2' to 
>> AX_CXX_COMPILE_STDCXX])])dnl
>> -  m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
>> -[$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
>> -[$3], [optional], [ax_cxx_compile_cxx$1_required=false],
>> -[m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
>> -  AC_LANG_PUSH([C++])dnl
>> -  ac_success=no
>> -  AC_CACHE_CHECK(whether $CXX supports C++$1 features 

Re: [Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Jose Fonseca]

On 15/04/16 00:30, Tim Rowley wrote:

On the philosophy that a driver shouldn't change the compile flags
for the entire tree, take the clove approach of moving the c++11 flag
to the swr driver directory.
---
  configure.ac|   9 +-
  m4/ax_cxx_compile_stdcxx.m4 | 558 
  src/gallium/drivers/swr/Makefile.am |   3 +-
  3 files changed, 9 insertions(+), 561 deletions(-)
  delete mode 100644 m4/ax_cxx_compile_stdcxx.m4

diff --git a/configure.ac b/configure.ac
index 8c82c43..6155942 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2265,15 +2265,20 @@ if test -n "$with_gallium_drivers"; then
  fi
  ;;
  xswr)
-AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
  swr_llvm_check "swr"

-AC_MSG_CHECKING([whether $CXX supports AVX/AVX2])
+AC_MSG_CHECKING([whether $CXX supports c++11/AVX/AVX2])
  AVX_CXXFLAGS="-march=core-avx-i"
  AVX2_CXXFLAGS="-march=core-avx2"

  AC_LANG_PUSH([C++])
  save_CXXFLAGS="$CXXFLAGS"
+CXXFLAGS="-std=c++11 $CXXFLAGS"
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
+  [AC_MSG_ERROR([c++11 compiler support not 
detected])])
+CXXFLAGS="$save_CXXFLAGS"
+
+save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$AVX_CXXFLAGS $CXXFLAGS"
  AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
[AC_MSG_ERROR([AVX compiler support not 
detected])])
diff --git a/m4/ax_cxx_compile_stdcxx.m4 b/m4/ax_cxx_compile_stdcxx.m4
deleted file mode 100644
index 079e17d..000
--- a/m4/ax_cxx_compile_stdcxx.m4
+++ /dev/null
@@ -1,558 +0,0 @@
-# ===
-#   http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
-# ===
-#
-# SYNOPSIS
-#
-#   AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
-#
-# DESCRIPTION
-#
-#   Check for baseline language coverage in the compiler for the specified
-#   version of the C++ standard.  If necessary, add switches to CXXFLAGS to
-#   enable support.  VERSION may be '11' (for the C++11 standard) or '14'
-#   (for the C++14 standard).
-#
-#   The second argument, if specified, indicates whether you insist on an
-#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
-#   -std=c++11).  If neither is specified, you get whatever works, with
-#   preference for an extended mode.
-#
-#   The third argument, if specified 'mandatory' or if left unspecified,
-#   indicates that baseline support for the specified C++ standard is
-#   required and that the macro should error out if no mode with that
-#   support is found.  If specified 'optional', then configuration proceeds
-#   regardless, after defining HAVE_CXX${VERSION} if and only if a
-#   supporting mode is found.
-#
-# LICENSE
-#
-#   Copyright (c) 2008 Benjamin Kosnik 
-#   Copyright (c) 2012 Zack Weinberg 
-#   Copyright (c) 2013 Roy Stogner 
-#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov 

-#   Copyright (c) 2015 Paul Norman 
-#   Copyright (c) 2015 Moritz Klammler 
-#
-#   Copying and distribution of this file, with or without modification, are
-#   permitted in any medium without royalty provided the copyright notice
-#   and this notice are preserved.  This file is offered as-is, without any
-#   warranty.
-
-#serial 1
-
-dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
-dnl  (serial version number 13).
-
-AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
-  m4_if([$1], [11], [],
-[$1], [14], [],
-[$1], [17], [m4_fatal([support for C++17 not yet implemented in 
AX_CXX_COMPILE_STDCXX])],
-[m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
-  m4_if([$2], [], [],
-[$2], [ext], [],
-[$2], [noext], [],
-[m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
-  m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
-[$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
-[$3], [optional], [ax_cxx_compile_cxx$1_required=false],
-[m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
-  AC_LANG_PUSH([C++])dnl
-  ac_success=no
-  AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
-  ax_cv_cxx_compile_cxx$1,
-  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
-[ax_cv_cxx_compile_cxx$1=yes],
-[ax_cv_cxx_compile_cxx$1=no])])
-  if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
-ac_success=yes
-  fi
-
-  m4_if([$2], [noext], [], [dnl
-  if test x$ac_success = xno; then
-for switch in -std=gnu++$1 -std=gnu++0x; do
-  

[Mesa-dev] [PATCH] gallium/swr: confine c++11 flag to swr driver

[Tim Rowley]

On the philosophy that a driver shouldn't change the compile flags
for the entire tree, take the clove approach of moving the c++11 flag
to the swr driver directory.
---
 configure.ac|   9 +-
 m4/ax_cxx_compile_stdcxx.m4 | 558 
 src/gallium/drivers/swr/Makefile.am |   3 +-
 3 files changed, 9 insertions(+), 561 deletions(-)
 delete mode 100644 m4/ax_cxx_compile_stdcxx.m4

diff --git a/configure.ac b/configure.ac
index 8c82c43..6155942 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2265,15 +2265,20 @@ if test -n "$with_gallium_drivers"; then
 fi
 ;;
 xswr)
-AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
 swr_llvm_check "swr"
 
-AC_MSG_CHECKING([whether $CXX supports AVX/AVX2])
+AC_MSG_CHECKING([whether $CXX supports c++11/AVX/AVX2])
 AVX_CXXFLAGS="-march=core-avx-i"
 AVX2_CXXFLAGS="-march=core-avx2"
 
 AC_LANG_PUSH([C++])
 save_CXXFLAGS="$CXXFLAGS"
+CXXFLAGS="-std=c++11 $CXXFLAGS"
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
+  [AC_MSG_ERROR([c++11 compiler support not 
detected])])
+CXXFLAGS="$save_CXXFLAGS"
+
+save_CXXFLAGS="$CXXFLAGS"
 CXXFLAGS="$AVX_CXXFLAGS $CXXFLAGS"
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],[],
   [AC_MSG_ERROR([AVX compiler support not 
detected])])
diff --git a/m4/ax_cxx_compile_stdcxx.m4 b/m4/ax_cxx_compile_stdcxx.m4
deleted file mode 100644
index 079e17d..000
--- a/m4/ax_cxx_compile_stdcxx.m4
+++ /dev/null
@@ -1,558 +0,0 @@
-# ===
-#   http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
-# ===
-#
-# SYNOPSIS
-#
-#   AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
-#
-# DESCRIPTION
-#
-#   Check for baseline language coverage in the compiler for the specified
-#   version of the C++ standard.  If necessary, add switches to CXXFLAGS to
-#   enable support.  VERSION may be '11' (for the C++11 standard) or '14'
-#   (for the C++14 standard).
-#
-#   The second argument, if specified, indicates whether you insist on an
-#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
-#   -std=c++11).  If neither is specified, you get whatever works, with
-#   preference for an extended mode.
-#
-#   The third argument, if specified 'mandatory' or if left unspecified,
-#   indicates that baseline support for the specified C++ standard is
-#   required and that the macro should error out if no mode with that
-#   support is found.  If specified 'optional', then configuration proceeds
-#   regardless, after defining HAVE_CXX${VERSION} if and only if a
-#   supporting mode is found.
-#
-# LICENSE
-#
-#   Copyright (c) 2008 Benjamin Kosnik 
-#   Copyright (c) 2012 Zack Weinberg 
-#   Copyright (c) 2013 Roy Stogner 
-#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov 

-#   Copyright (c) 2015 Paul Norman 
-#   Copyright (c) 2015 Moritz Klammler 
-#
-#   Copying and distribution of this file, with or without modification, are
-#   permitted in any medium without royalty provided the copyright notice
-#   and this notice are preserved.  This file is offered as-is, without any
-#   warranty.
-
-#serial 1
-
-dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
-dnl  (serial version number 13).
-
-AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
-  m4_if([$1], [11], [],
-[$1], [14], [],
-[$1], [17], [m4_fatal([support for C++17 not yet implemented in 
AX_CXX_COMPILE_STDCXX])],
-[m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
-  m4_if([$2], [], [],
-[$2], [ext], [],
-[$2], [noext], [],
-[m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
-  m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
-[$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
-[$3], [optional], [ax_cxx_compile_cxx$1_required=false],
-[m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
-  AC_LANG_PUSH([C++])dnl
-  ac_success=no
-  AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
-  ax_cv_cxx_compile_cxx$1,
-  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
-[ax_cv_cxx_compile_cxx$1=yes],
-[ax_cv_cxx_compile_cxx$1=no])])
-  if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
-ac_success=yes
-  fi
-
-  m4_if([$2], [noext], [], [dnl
-  if test x$ac_success = xno; then
-for switch in -std=gnu++$1 -std=gnu++0x; do
-  cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
-