Misc. CMake fixes

This reverts commit 4b0120183404913f7f7788ef4f0f6b51498ef363.

Before reverting this patch, CMake packages are built with the following options:
* if BR2_ENABLE_DEBUG is set:
The CMake build type is set to RelWithDebInfo, which means:
- Optimization level is forced to: -O2;
- no log nor assert due to -DNDEBUG;
- BR2_DEBUG_{1..3} effect is unchanged;
* otherwise:
The CMake build type is set to Release, which means:
- Optimization level is forced to: -O3;
- no log nor assert due to -DNDEBUG (as expected).
In any case, the optimization WRT the binary size is always ignored and forced.

Reverting to the previous situation, so Buildroot now chooses between the 'Debug' and 'Release' config types, which are semantically closer to what Buildroot does everywhere else:
* if BR2_ENABLE_DEBUG is set:
The CMake build type is set to Debug, which means:
- only -g option is passed by CMake;
- optimization is not forced, nor debug level, so they are kept as-is;
* otherwise:
The CMake build type is set to Release, so no change in this case:
- Optimization level is forced to: -O3;
- no log nor assert due to -DNDEBUG (as expected);
- size optimization is ignored.

Follow-up patches will fix the CMake flag variables that are appended by CMake.

Cc Charles Hardin <[email protected]>

Cc Arnout Vandecappelle (Essensium/Mind) <[email protected]>

Cc Maxime Hadjinlian <[email protected]>

Signed-off-by Samuel Martin <[email protected]>

---
changes v5->v6:
- revert 4b01201 instead (Arnout)

changes v4->v5:
- none

changes v3->v4:
- simplify build type selection

---
 package/pkg-cmake.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

package/pkg-cmake.mk +1 -1

index aca9e61..4883b3b 100644
@@ -87,7 +87,7 @@ define $(2)_CONFIGURE_CMDS
 	PATH=$$(BR_PATH) \
 	$$($$(PKG)_CONF_ENV) $$(BR2_CMAKE) $$($$(PKG)_SRCDIR) \
 		-DCMAKE_TOOLCHAIN_FILE="$$(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake" \
-		-DCMAKE_BUILD_TYPE=$$(if $$(BR2_ENABLE_DEBUG),RelWithDebInfo,Release) \
+		-DCMAKE_BUILD_TYPE=$$(if $$(BR2_ENABLE_DEBUG),Debug,Release) \
 		-DCMAKE_INSTALL_PREFIX="/usr" \
 		-DCMAKE_COLOR_MAKEFILE=OFF \
 		-DBUILD_DOC=OFF \

The chosen CMAKE_BUILD_TYPE encodes an option of the Buildroot configuration, so it makes more sense to save it in the toolchainfile.cmake than to pass it during configure.

It is still possible to override the build type on the cmake command line.

Cc Arnout Vandecappelle (Essensium/Mind) <[email protected]>

Cc Maxime Hadjinlian <[email protected]>

Signed-off-by Samuel Martin <[email protected]>

---
changes v5->v6:
- reword commit log (Arnout)
- simplify/remove intermediate variable (Arnout)

changes v4->v5:
- fix cmake set call

changes v3->v4:
- new patch

---
 CHANGES                             | 6 ++++++
 package/pkg-cmake.mk                | 2 +-
 support/misc/toolchainfile.cmake.in | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

CHANGES +0 -0

index b4bd5fe..c0e3e79 100644

CHANGES +1 -0

+
 2016.08, Released September 1st, 2016
 
 	Minor fixes.

package/pkg-cmake.mk +1 -1

index 4883b3b..4e0e838 100644
@@ -87,7 +87,6 @@ define $(2)_CONFIGURE_CMDS
 	PATH=$$(BR_PATH) \
 	$$($$(PKG)_CONF_ENV) $$(BR2_CMAKE) $$($$(PKG)_SRCDIR) \
 		-DCMAKE_TOOLCHAIN_FILE="$$(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake" \
-		-DCMAKE_BUILD_TYPE=$$(if $$(BR2_ENABLE_DEBUG),Debug,Release) \
 		-DCMAKE_INSTALL_PREFIX="/usr" \
 		-DCMAKE_COLOR_MAKEFILE=OFF \
 		-DBUILD_DOC=OFF \

@@ -247,5 +246,6 @@ $(HOST_DIR)/usr/share/buildroot/toolchainfile.cmake:
 		-e 's#@@TARGET_FC@@#$(subst $(HOST_DIR)/,,$(call qstrip,$(TARGET_FC)))#' \
 		-e 's#@@CMAKE_SYSTEM_PROCESSOR@@#$(call qstrip,$(CMAKE_SYSTEM_PROCESSOR))#' \
 		-e 's#@@TOOLCHAIN_HAS_FORTRAN@@#$(if $(BR2_TOOLCHAIN_HAS_FORTRAN),1,0)#' \
+		-e 's#@@CMAKE_BUILD_TYPE@@#$(if $(BR2_ENABLE_DEBUG),Debug,Release)#' \
 		$(TOPDIR)/support/misc/toolchainfile.cmake.in \
 		> $@

support/misc/toolchainfile.cmake.in +3 -0

index 649b52d..1c5031f 100644
@@ -13,6 +13,9 @@ string(REPLACE "/usr/share/buildroot" "" RELOCATED_HOST_DIR ${CMAKE_CURRENT_LIST
 set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_SYSTEM_PROCESSOR @@CMAKE_SYSTEM_PROCESSOR@@)
 
+# Build type from the Buildroot configuration
+set(CMAKE_BUILD_TYPE @@CMAKE_BUILD_TYPE@@ CACHE STRING "Buildroot build configuration")
+
 set(CMAKE_C_FLAGS "@@TARGET_CFLAGS@@ ${CMAKE_C_FLAGS}" CACHE STRING "Buildroot CFLAGS")
 set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
 set(CMAKE_EXE_LINKER_FLAGS "@@TARGET_LDFLAGS@@ ${CMAKE_EXE_LINKER_FLAGS}" CACHE STRING "Buildroot LDFLAGS")

When a build type is set, CMake does append some flags that can override those set by Buildroot due to the gcc option parser (in which the last argument controling an option wins).

Hereafter is a summary of the optimization and debug flags set by Buildroot and appended by CMake.

* Flags set by Buildroot depending on the configuration:

BR2_ENABLE_DEBUG | Optim. level | Buildroot {C,CXX}FLAGS
=================+=====================+=======================

          y        | BR2_OPTIMIZE_S      | -Os -gx
          y        | BR2_OPTIMIZE_G      | -Og -gx
          y        | BR2_OPTIMIZE_{0..3} | -On -gx
          n        | BR2_OPTIMIZE_S      | -Os
          n        | BR2_OPTIMIZE_G      | -Og
          n        | BR2_OPTIMIZE_{0..3} | -On

* Default flags appended by CMake depending on the build type:

Build type | Flags | Effects on {C,CXX}FLAGS
===============+=================+===========================================

  Debug          | -g              | Force -g, compatible with BR2_ENABLE_DEBUG
  MinSizeRel     | -Os -DNDEBUG    | Set -Os, compatible with BR2_OPTIMIZE_S
  Release        | -O3 -DNDEBUG    | Set -O3, closest to the others cases,
                 |                 | though the optimization level is forced.
  RelWithDebInfo | -O2 -g -DNDEBUG | Force -g and set -O2, not friendly with BR

To avoid the CMake flags take precedence over the Buildroot ones, this change sets in toolchainfile.cmake the per-config compiler flags CMake can append depending on the build type Buildroot defined. So, CMake does not mess up with the compilation flags Buildroot sets.

It is still possible to override these per-config flags on the cmake command line.

Note:
If a CMake-based project forces the compiler and/or linker flag definitions (the default ones or the per-config ones - e.g. CMAKE_C_FLAGS/CMAKE_C_FLAGS_{DEBUG,RELEASE}), there is not much Buildroot can do about it.
So, the flags will be overwritten anyway in these cases.

Cc Arnout Vandecappelle (Essensium/Mind) <[email protected]>

Cc Maxime Hadjinlian <[email protected]>

Signed-off-by Samuel Martin <[email protected]>

---
changes v5->v6:
- reword commit log

changes v4->v5:
- fix cmake set call

changes v3->v4:
- new patch

---
 support/misc/toolchainfile.cmake.in | 11 +++++++++++
 1 file changed, 11 insertions(+)

support/misc/toolchainfile.cmake.in +0 -0

index 1c5031f..2ace940 100644

support/misc/toolchainfile.cmake.in +1 -0

+
 # Build type from the Buildroot configuration
 set(CMAKE_BUILD_TYPE @@CMAKE_BUILD_TYPE@@ CACHE STRING "Buildroot build configuration")
 

Quoted 1 line

From the build configuration, Buildroot defines and set some compiler

and linker flags that should be passed to any packages build-system.

For package using the cmake-package infrastructure, this is achieved

via the toolchainfile.cmake.

This change simplifies the way the toolchainfile.cmake file handles these flags: it now just sets them, without any attempt to extend them with those Buildroot defined.

This change still allows overriding these flags from the configure command line.

So, now, when a CMake-based package needs to extend them, they should be fully set from the package *.mk file. This behavior is consistent with what is done for others package infrastructures.

This change should not pull any regression WRT the bug #7280 [1].

However, now, when someone uses the toolchainfile.cmake file outside of Buildroot, he/she must overload all compiler/linker flags (including the ones Buildroot sets since they no longer get automatically added).

[1] https://bugs.busybox.net/show_bug.cgi?id=7280

Cc Arnout Vandecappelle (Essensium/Mind) <[email protected]>

Cc Max Filippov <[email protected]>

Cc Thomas Petazzoni <[email protected]>

Signed-off-by Samuel Martin <[email protected]>

---
changes v5->v6:
- none

changes v4->v5:
- fix cmake set call

changes v3->v4:
- add a note about what the CMake code should look like (Arnout)
- fix overriding support (add missing CACHE keyword)
- update CHANGES text

---
 CHANGES                             |  5 ++++-
 support/misc/toolchainfile.cmake.in | 17 +++++++++++++----
 2 files changed, 17 insertions(+), 5 deletions(-)

CHANGES +0 -0

index c0e3e79..3657710 100644

CHANGES +3 -0

+    * when used outside of Buildroot with custom compiler/linker
+      flags, the Buildroot flags should be set along side with the
+      custom ones.
 
 2016.08, Released September 1st, 2016
 

support/misc/toolchainfile.cmake.in +13 -4

index 2ace940..0283b62 100644
@@ -27,9 +27,17 @@ set(CMAKE_CXX_FLAGS_RELEASE " -DNEBUG" CACHE STRING "Release CXXFLAGS")
 # Build type from the Buildroot configuration
 set(CMAKE_BUILD_TYPE @@CMAKE_BUILD_TYPE@@ CACHE STRING "Buildroot build configuration")
 
-set(CMAKE_C_FLAGS "@@TARGET_CFLAGS@@ ${CMAKE_C_FLAGS}" CACHE STRING "Buildroot CFLAGS")
-set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
-set(CMAKE_EXE_LINKER_FLAGS "@@TARGET_LDFLAGS@@ ${CMAKE_EXE_LINKER_FLAGS}" CACHE STRING "Buildroot LDFLAGS")
+# Buildroot defaults flags.
+# If you are using this toolchainfile.cmake file outside of Buildroot and
+# want to customize the compiler/linker flags, then:
+# * set them all on the cmake command line, e.g.:
+#     cmake -DCMAKE_C_FLAGS="@@TARGET_CFLAGS@@ -Dsome_custom_flag" ...
+# * and make sure the project's CMake code extendsthem like this if needed:
+#     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Dsome_definitions")
+set(CMAKE_C_FLAGS "@@TARGET_CFLAGS@@" CACHE STRING "Buildroot CFLAGS")
+set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@" CACHE STRING "Buildroot CXXFLAGS")
+set(CMAKE_EXE_LINKER_FLAGS "@@TARGET_LDFLAGS@@" CACHE STRING "Buildroot LDFLAGS for executables")
+
 set(CMAKE_INSTALL_SO_NO_EXE 0)
 
 set(CMAKE_PROGRAM_PATH "${RELOCATED_HOST_DIR}/usr/bin")

@@ -45,6 +53,7 @@ set(ENV{PKG_CONFIG_SYSROOT_DIR} "${RELOCATED_HOST_DIR}/@@STAGING_SUBDIR@@")
 set(CMAKE_C_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CC@@")
 set(CMAKE_CXX_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_CXX@@")
 if(@@TOOLCHAIN_HAS_FORTRAN@@)
-  set(CMAKE_Fortran_FLAGS "@@TARGET_FCFLAGS@@ ${CMAKE_Fortran_FLAGS}" CACHE STRING "Buildroot FCFLAGS")
+  # Buildroot defaults flags.
+  set(CMAKE_Fortran_FLAGS "@@TARGET_FCFLAGS@@" CACHE STRING "Buildroot FCFLAGS")
   set(CMAKE_Fortran_COMPILER "${RELOCATED_HOST_DIR}/@@TARGET_FC@@")
 endif()

Max Filippov (1):
package/opencv3: fix CMAKE_CXX_FLAGS

Samuel Martin (8):
Revert "package/cmake: with BR2_ENABLE_DEBUG use RelWithDebInfo" package/pkg-cmake.mk: move CMAKE_BUILD_TYPE definition into
toolchainfile.cmake
toolchainfile.cmake: set per-config appended {C,CXX}FLAGS package/gflags: include TARGET_CXXFLAGS to the overloaded CXXFLAGS package/gnuradio: include TARGET_CFLAGS to the overloaded CFLAGS package/libcec: include TARGET_{C,CXX}FLAGS to the overloaded
{C,CXX}FLAGS
package/rpi-userland: include TARGET_CFLAGS to the overloaded CFLAGS toochainfile.cmake: rework the way Buildroot sets flags

Hello,

Quoted 14 lines · Samuel Martin

Max Filippov (1):
package/opencv3: fix CMAKE_CXX_FLAGS

Samuel Martin (8):
Revert "package/cmake: with BR2_ENABLE_DEBUG use RelWithDebInfo" package/pkg-cmake.mk: move CMAKE_BUILD_TYPE definition into
toolchainfile.cmake
toolchainfile.cmake: set per-config appended {C,CXX}FLAGS package/gflags: include TARGET_CXXFLAGS to the overloaded CXXFLAGS package/gnuradio: include TARGET_CFLAGS to the overloaded CFLAGS package/libcec: include TARGET_{C,CXX}FLAGS to the overloaded
{C,CXX}FLAGS
package/rpi-userland: include TARGET_CFLAGS to the overloaded CFLAGS toochainfile.cmake: rework the way Buildroot sets flags

I've applied the series. I've done a few changes on specific patches, I'll reply to the patches themselves.