[PATCH v2 03/10] Use unsigned as base type for some enums

[Tom Tromey <tom@tromey.com>]

-fsanitize=undefined complains about using operator~ on various enum
types that are used with DEF_ENUM_FLAGS_TYPE.  This patch fixes these
problems by explicitly setting the base type for these enums to
unsigned.  It also adds a static assert to enum_flags to ensure that
future enums used this way have an unsigned underlying type.

gdb/ChangeLog
2018-10-01  Tom Tromey  <tom@tromey.com>

	* common/enum-flags.h (enum_flags::operator~): Add static assert.
	* symfile-add-flags.h (enum symfile_add_flag): Use unsigned as
	base type.
	* objfile-flags.h (enum objfile_flag): Use unsigned as base type.
	* gdbtypes.h (enum type_instance_flag_value): Use unsigned as base
	type.
	* c-lang.h (enum c_string_type_values): Use unsigned as base
	type.
	* btrace.h (enum btrace_thread_flag): Use unsigned as base type.
---
 gdb/ChangeLog           | 12 ++++++++++++
 gdb/btrace.h            |  2 +-
 gdb/c-lang.h            |  2 +-
 gdb/common/enum-flags.h |  1 +
 gdb/gdbtypes.h          |  2 +-
 gdb/objfile-flags.h     |  2 +-
 gdb/symfile-add-flags.h |  2 +-
 7 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/gdb/btrace.h b/gdb/btrace.h
index bfb0b9f278..0448bd6d49 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -228,7 +228,7 @@ struct btrace_call_history
 };
 
 /* Branch trace thread flags.  */
-enum btrace_thread_flag
+enum btrace_thread_flag : unsigned
 {
   /* The thread is to be stepped forwards.  */
   BTHR_STEP = (1 << 0),
diff --git a/gdb/c-lang.h b/gdb/c-lang.h
index ae17abd20f..f9eab04730 100644
--- a/gdb/c-lang.h
+++ b/gdb/c-lang.h
@@ -35,7 +35,7 @@ struct parser_state;
 /* The various kinds of C string and character.  Note that these
    values are chosen so that they may be or'd together in certain
    ways.  */
-enum c_string_type_values
+enum c_string_type_values : unsigned
   {
     /* An ordinary string: "value".  */
     C_STRING = 0,
diff --git a/gdb/common/enum-flags.h b/gdb/common/enum-flags.h
index 82568a5a3d..dad59cec86 100644
--- a/gdb/common/enum-flags.h
+++ b/gdb/common/enum-flags.h
@@ -164,6 +164,7 @@ public:
   }
   enum_flags operator~ () const
   {
+    gdb_static_assert (std::is_unsigned<underlying_type>::value);
     return (enum_type) ~underlying_value ();
   }
 
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 32b58dcc61..a115857c0a 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -193,7 +193,7 @@ enum type_code
 /* * Some bits for the type's instance_flags word.  See the macros
    below for documentation on each bit.  */
 
-enum type_instance_flag_value
+enum type_instance_flag_value : unsigned
 {
   TYPE_INSTANCE_FLAG_CONST = (1 << 0),
   TYPE_INSTANCE_FLAG_VOLATILE = (1 << 1),
diff --git a/gdb/objfile-flags.h b/gdb/objfile-flags.h
index aeaa8fbc04..6f5760d021 100644
--- a/gdb/objfile-flags.h
+++ b/gdb/objfile-flags.h
@@ -25,7 +25,7 @@
 /* Defines for the objfile flags field.  Defined in a separate file to
    break circular header dependencies.  */
 
-enum objfile_flag
+enum objfile_flag : unsigned
   {
     /* When an object file has its functions reordered (currently
        Irix-5.2 shared libraries exhibit this behaviour), we will need
diff --git a/gdb/symfile-add-flags.h b/gdb/symfile-add-flags.h
index 3c07513e39..35241fe4a0 100644
--- a/gdb/symfile-add-flags.h
+++ b/gdb/symfile-add-flags.h
@@ -26,7 +26,7 @@
    symbol_file_add, etc.  Defined in a separate file to break circular
    header dependencies.  */
 
-enum symfile_add_flag
+enum symfile_add_flag : unsigned
   {
     /* Be chatty about what you are doing.  */
     SYMFILE_VERBOSE = 1 << 1,
-- 
2.17.1