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, 2 insertions, 2 deletions

diff --git a/src/arch/x86/isa.cc b/src/arch/x86/isa.cc
index 9dd7fbb52..f092f4418 100644
--- a/src/arch/x86/isa.cc
+++ b/src/arch/x86/isa.cc
@@ -316,7 +316,7 @@ ISA::setMiscReg(int miscReg, MiscReg val, ThreadContext * tc)
         break;
       case MISCREG_DR4:
         miscReg = MISCREG_DR6;
-        /* Fall through to have the same effects as DR6. */
+        M5_FALLTHROUGH;
       case MISCREG_DR6:
         {
             DR6 dr6 = regVal[MISCREG_DR6];
@@ -333,7 +333,7 @@ ISA::setMiscReg(int miscReg, MiscReg val, ThreadContext * tc)
         break;
       case MISCREG_DR5:
         miscReg = MISCREG_DR7;
-        /* Fall through to have the same effects as DR7. */
+        M5_FALLTHROUGH;
       case MISCREG_DR7:
         {
             DR7 dr7 = regVal[MISCREG_DR7];