misc: Updates for gcc7.2 for x86

GCC 7.2 is much stricter than previous GCC versions. The following changes
are needed:

* There is now a warning if there is an implicit fallthrough between two
  case statments. C++17 adds the [[fallthrough]]; declaration. However,
  to support non C++17 standards (i.e., C++11), we use M5_FALLTHROUGH.
  M5_FALLTHROUGH checks for [[fallthrough]] compliant C++17 compiler and
  if that doesn't exist, it defaults to nothing (no older compilers
  generate warnings).
* The above resulted in a couple of bugs that were found. This is noted
  in the review request on gerrit.
* throw() for dynamic exception specification is deprecated
* There were a couple of new uninitialized variable warnings
* Can no longer perform bitwise operations on a bool.
* Must now include <functional> for std::function
* Compiler bug for void* lambda. Changed to auto as work around. See
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82878

Change-Id: I5d4c782a4e133fa4cdb119e35d9aff68c6e2958e
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/5802
Reviewed-by: Gabe Black <gabeblack@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/cpu/minor/dyn_inst.cc b/src/cpu/minor/dyn_inst.cc
index 756b214bd..353163758 100644
--- a/src/cpu/minor/dyn_inst.cc
+++ b/src/cpu/minor/dyn_inst.cc
@@ -169,6 +169,7 @@ printRegName(std::ostream &os, const RegId& reg)
         break;
       case CCRegClass:
         os << 'c' << static_cast<unsigned int>(reg.index());
+        break;
       default:
         panic("Unknown register class: %d", (int)reg.classValue());
     }