C99 is now the C standard for all our C code.

The main new feature is mixed variable declarations and code, which can help
reduce uninitialized variables or accidental variable reuse.

Due to incomplete C99 support in VS 2013, variable length arrays are not
supported, BLI_array_alloca must still be used. The header <tgmath.h> is also
not supported.

Differential Revision: https://developer.blender.org/D1631

8 files changed, 23 insertions, 14 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 14eb2af58a4..b5317ccb724 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1189,12 +1189,6 @@ if(UNIX AND NOT APPLE)
 	if(CMAKE_COMPILER_IS_GNUCC)
 		set(PLATFORM_CFLAGS "-pipe -fPIC -funsigned-char -fno-strict-aliasing")
 
-		if(NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "5.0")
-			# GCC5 uses gnu11, until we update, force c89
-			# though some c11 features can still be used.
-			set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu89")
-		endif()
-
 		# use ld.gold linker if available, could make optional
 		execute_process(
 		        COMMAND ${CMAKE_C_COMPILER} -fuse-ld=gold -Wl,--version
@@ -2577,9 +2571,9 @@ if(CMAKE_COMPILER_IS_GNUCC)
 
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ALL -Wall)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_CAST_ALIGN -Wcast-align)
-	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_DECLARATION_AFTER_STATEMENT -Werror=declaration-after-statement)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_IMPLICIT_FUNCTION_DECLARATION -Werror=implicit-function-declaration)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_RETURN_TYPE  -Werror=return-type)
+	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_VLA -Werror=vla)
 	# system headers sometimes do this, disable for now, was: -Werror=strict-prototypes
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_STRICT_PROTOTYPES  -Wstrict-prototypes)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_MISSING_PROTOTYPES -Wmissing-prototypes)
@@ -2624,7 +2618,6 @@ if(CMAKE_COMPILER_IS_GNUCC)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_DIV_BY_ZERO -Wno-div-by-zero)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_TYPE_LIMITS -Wtype-limits)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_ERROR_RETURN_TYPE  -Werror=return-type)
-	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_ERROR_DECLARATION_AFTER_STATEMENT -Werror=declaration-after-statement)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_ERROR_IMPLICIT_FUNCTION_DECLARATION -Werror=implicit-function-declaration)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_CHAR_SUBSCRIPTS -Wno-char-subscripts)
 	ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_UNKNOWN_PRAGMAS -Wno-unknown-pragmas)
@@ -2661,7 +2654,6 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
 
 	# strange, clang complains these are not supported, but then yses them.
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ALL -Wall)
-	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_DECLARATION_AFTER_STATEMENT -Werror=declaration-after-statement)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_IMPLICIT_FUNCTION_DECLARATION -Werror=implicit-function-declaration)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_ERROR_RETURN_TYPE  -Werror=return-type)
 	ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_NO_AUTOLOGICAL_COMPARE -Wno-tautological-compare)
@@ -2776,6 +2768,13 @@ if(WITH_CPP11)
 	endif()
 endif()
 
+if(MSVC)
+	# Visual Studio has all standards it supports available by default
+else()
+	# Use C99 + GNU extensions, works with GCC, Clang, ICC
+	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
+endif()
+
 # Include warnings first, so its possible to disable them with user defined flags
 # eg: -Wno-uninitialized
 set(CMAKE_C_FLAGS "${C_WARNINGS} ${CMAKE_C_FLAGS} ${PLATFORM_CFLAGS}")
diff --git a/SConstruct b/SConstruct
index ebd9cd1ec90..29f539236c2 100644
--- a/SConstruct
+++ b/SConstruct
@@ -498,6 +498,13 @@ if env['WITH_BF_CPP11']:
     else:
         env['CXXFLAGS'].append('-std=c++11')
 
+if env['OURPLATFORM'] in ('win32-vc', 'win64-vc'):
+    # Visual Studio has all standards it supports available by default
+    pass
+else:
+    # Use C99 + GNU extensions, works with GCC, Clang, ICC
+    env['CFLAGS'].append('-std=gnu99')
+
 #check for additional debug libnames
 
 if env.has_key('BF_DEBUG_LIBS'):
diff --git a/build_files/scons/config/darwin-config.py b/build_files/scons/config/darwin-config.py
index 0bf03a46bd2..16ba3ec4133 100644
--- a/build_files/scons/config/darwin-config.py
+++ b/build_files/scons/config/darwin-config.py
@@ -248,7 +248,7 @@ REL_CXXFLAGS = []
 REL_CCFLAGS = ['-O2']
 
 CC_WARN = ['-Wall']
-C_WARN = ['-Wno-char-subscripts', '-Wpointer-arith', '-Wcast-align', '-Wdeclaration-after-statement', '-Wno-unknown-pragmas', '-Wstrict-prototypes']
+C_WARN = ['-Wno-char-subscripts', '-Wpointer-arith', '-Wcast-align', '-Wvla', '-Wno-unknown-pragmas', '-Wstrict-prototypes']
 CXX_WARN = ['-Wno-invalid-offsetof', '-Wno-sign-compare']
 
 ##FIX_STUBS_WARNINGS = -Wno-unused
diff --git a/build_files/scons/config/linux-config.py b/build_files/scons/config/linux-config.py
index ff8ecf0aa72..1990d6ece0a 100644
--- a/build_files/scons/config/linux-config.py
+++ b/build_files/scons/config/linux-config.py
@@ -254,7 +254,7 @@ REL_CFLAGS = []
 REL_CXXFLAGS = []
 REL_CCFLAGS = ['-O2']
 
-C_WARN = ['-Wno-char-subscripts', '-Wdeclaration-after-statement', '-Wunused-parameter', '-Wstrict-prototypes', '-Werror=declaration-after-statement', '-Werror=implicit-function-declaration', '-Werror=return-type']
+C_WARN = ['-Wno-char-subscripts', '-Wvla', '-Wunused-parameter', '-Wstrict-prototypes', '-Werror=vla', '-Werror=implicit-function-declaration', '-Werror=return-type']
 CC_WARN = ['-Wall']
 CXX_WARN = ['-Wno-invalid-offsetof', '-Wno-sign-compare']
 
diff --git a/build_files/scons/config/win32-mingw-config.py b/build_files/scons/config/win32-mingw-config.py
index 552a1a5cec3..f4b709dda81 100644
--- a/build_files/scons/config/win32-mingw-config.py
+++ b/build_files/scons/config/win32-mingw-config.py
@@ -202,7 +202,7 @@ REL_CFLAGS = []
 REL_CXXFLAGS = []
 REL_CCFLAGS = ['-O2']
 
-C_WARN = ['-Wno-char-subscripts', '-Wdeclaration-after-statement', '-Wstrict-prototypes']
+C_WARN = ['-Wno-char-subscripts', '-Wvla', '-Wstrict-prototypes']
 
 CC_WARN = [ '-Wall' ]
 
diff --git a/build_files/scons/config/win64-mingw-config.py b/build_files/scons/config/win64-mingw-config.py
index 87a9b5e4eac..6106f2ac631 100644
--- a/build_files/scons/config/win64-mingw-config.py
+++ b/build_files/scons/config/win64-mingw-config.py
@@ -197,7 +197,7 @@ REL_CXXFLAGS = []
 REL_CCFLAGS = ['-O2', '-ftree-vectorize']
 
 # NOTE: C_WARN seems to get ignored - at least -Wno-char-subscripts doesn't work!
-C_WARN = ['-Wno-char-subscripts', '-Wdeclaration-after-statement', '-Wstrict-prototypes']
+C_WARN = ['-Wno-char-subscripts', '-Wvla', '-Wstrict-prototypes']
 
 CC_WARN = [ '-Wall', '-Wno-char-subscripts' ]
 
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index b7742d82991..57e37c0190d 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -30,6 +30,9 @@
  */
 
 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+#  ifdef __GNUC__
+#    pragma GCC diagnostic ignored "-Wvla"
+#  endif
 #  define USE_DYNSIZE
 #endif
 
diff --git a/source/blender/python/mathutils/mathutils_Matrix.c b/source/blender/python/mathutils/mathutils_Matrix.c
index 7ad20d41bf1..71288871104 100644
--- a/source/blender/python/mathutils/mathutils_Matrix.c
+++ b/source/blender/python/mathutils/mathutils_Matrix.c
@@ -2055,7 +2055,7 @@ static PyObject *Matrix_richcmpr(PyObject *a, PyObject *b, int op)
 
 static Py_hash_t Matrix_hash(MatrixObject *self)
 {
-	float mat[SQUARE(MATRIX_MAX_DIM)];
+	float mat[MATRIX_MAX_DIM * MATRIX_MAX_DIM];
 
 	if (BaseMath_ReadCallback(self) == -1)
 		return -1;