Add -Wno-nested-anon-types to -pedantic builds of LLVM. This Clang wa…

…rning

catches uses of an extremely minor and widely-available C++ extension (which
every C++ compiler I could find supports, but EDG and Clang reject in strict
mode).

The diagnosed code pattern looks like this:

struct X {
  union {
    struct {
      int a;
      int b;
    } S;
  };
};


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174103 91177308-0d34-0410-b5e6-96231b3b80d8

Makefile.config.in

@@ -366,6 +366,8 @@ COVERED_SWITCH_DEFAULT = @COVERED_SWITCH_DEFAULT@
 NO_UNINITIALIZED = @NO_UNINITIALIZED@
 # -Wno-maybe-uninitialized
 NO_MAYBE_UNINITIALIZED = @NO_MAYBE_UNINITIALIZED@
+# -Wno-nested-anon-types
+NO_NESTED_ANON_TYPES = @NO_NESTED_ANON_TYPES@
 
 # Was polly found in tools/polly?
 LLVM_HAS_POLLY = @LLVM_HAS_POLLY@

Makefile.rules

@@ -665,7 +665,7 @@ LD.Flags += $(EXTRA_LD_OPTIONS)
 endif
 
 ifndef NO_PEDANTIC
-CompileCommonOpts += -pedantic -Wno-long-long
+CompileCommonOpts += -pedantic -Wno-long-long $(NO_NESTED_ANON_TYPES)
 endif
 CompileCommonOpts += -Wall -W -Wno-unused-parameter -Wwrite-strings \
                      $(EXTRA_OPTIONS) $(COVERED_SWITCH_DEFAULT) \

autoconf/configure.ac

@@ -1264,6 +1264,7 @@ dnl Check optional compiler flags.
 AC_MSG_CHECKING([optional compiler flags])
 CXX_FLAG_CHECK(NO_VARIADIC_MACROS, [-Wno-variadic-macros])
 CXX_FLAG_CHECK(NO_MISSING_FIELD_INITIALIZERS, [-Wno-missing-field-initializers])
+CXX_FLAG_CHECK(NO_NESTED_ANON_TYPES, [-Wno-nested-anon-types])
 CXX_FLAG_CHECK(COVERED_SWITCH_DEFAULT, [-Wcovered-switch-default])
 dnl GCC's potential uninitialized use analysis is weak and presents lots of
 dnl false positives, so disable it.
@@ -1299,7 +1300,7 @@ else
   NO_UNINITIALIZED=
   NO_MAYBE_UNINITIALIZED=
 fi
-AC_MSG_RESULT([$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED])
+AC_MSG_RESULT([$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $NO_NESTED_ANON_TYPES $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED])
 
 AC_ARG_WITH([python],
             [AS_HELP_STRING([--with-python], [path to python])],

cmake/modules/HandleLLVMOptions.cmake

@@ -193,6 +193,10 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
 
     if (LLVM_ENABLE_PEDANTIC)
       add_llvm_definitions( -pedantic -Wno-long-long )
+      check_cxx_compiler_flag("-Werror -Wnested-anon-types" CXX_SUPPORTS_NO_NESTED_ANON_TYPES_FLAG)
+      if( CXX_SUPPORTS_NO_NESTED_ANON_TYPES_FLAG )
+        set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-nested-anon-types" )
+      endif()
     endif (LLVM_ENABLE_PEDANTIC)
     check_cxx_compiler_flag("-Werror -Wcovered-switch-default" CXX_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG)
     if( CXX_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG )

configure

@@ -766,6 +766,7 @@ CONVENIENCE_LTDL_FALSE
 LIBADD_DL
 NO_VARIADIC_MACROS
 NO_MISSING_FIELD_INITIALIZERS
+NO_NESTED_ANON_TYPES
 COVERED_SWITCH_DEFAULT
 NO_MAYBE_UNINITIALIZED
 NO_UNINITIALIZED
@@ -12260,6 +12261,8 @@ NO_VARIADIC_MACROS=`$CXX -Werror -Wno-variadic-macros -fsyntax-only -xc /dev/nul
 
 NO_MISSING_FIELD_INITIALIZERS=`$CXX -Werror -Wno-missing-field-initializers -fsyntax-only -xc /dev/null 2>/dev/null && echo -Wno-missing-field-initializers`
 
+NO_NESTED_ANON_TYPES=`$CXX -Werror -Wno-nested-anon-types -fsyntax-only -xc /dev/null 2>/dev/null && echo -Wno-nested-anon-types`
+
 COVERED_SWITCH_DEFAULT=`$CXX -Werror -Wcovered-switch-default -fsyntax-only -xc /dev/null 2>/dev/null && echo -Wcovered-switch-default`
 
 if test "$GXX" = "yes"
@@ -12289,8 +12292,8 @@ else
   NO_UNINITIALIZED=
   NO_MAYBE_UNINITIALIZED=
 fi
-{ echo "$as_me:$LINENO: result: $NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&5
-echo "${ECHO_T}$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&6; }
+{ echo "$as_me:$LINENO: result: $NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $NO_NESTED_ANON_TYPES $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&5
+echo "${ECHO_T}$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $NO_NESTED_ANON_TYPES $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&6; }
 
 
 # Check whether --with-python was given.
@@ -22478,6 +22481,7 @@ CONVENIENCE_LTDL_FALSE!$CONVENIENCE_LTDL_FALSE$ac_delim
 LIBADD_DL!$LIBADD_DL$ac_delim
 NO_VARIADIC_MACROS!$NO_VARIADIC_MACROS$ac_delim
 NO_MISSING_FIELD_INITIALIZERS!$NO_MISSING_FIELD_INITIALIZERS$ac_delim
+NO_NESTED_ANON_TYPES!$NO_NESTED_ANON_TYPES$ac_delim
 COVERED_SWITCH_DEFAULT!$COVERED_SWITCH_DEFAULT$ac_delim
 NO_MAYBE_UNINITIALIZED!$NO_MAYBE_UNINITIALIZED$ac_delim
 NO_UNINITIALIZED!$NO_UNINITIALIZED$ac_delim