clang: Enable compiling gem5 using clang 2.9 and 3.0

This patch adds the necessary flags to the SConstruct and SConscript
files for compiling using clang 2.9 and later (on Ubuntu et al and OSX
XCode 4.2), and also cleans up a bunch of compiler warnings found by
clang. Most of the warnings are related to hidden virtual functions,
comparisons with unsigneds >= 0, and if-statements with empty
bodies. A number of mismatches between struct and class are also
fixed. clang 2.8 is not working as it has problems with class names
that occur in multiple namespaces (e.g. Statistics in
kernel_stats.hh).

clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which
causes confusion between the container std::set and the function
Packet::set, and this is currently addressed by not including the
entire namespace std, but rather selecting e.g. "using std::vector" in
the appropriate places.

1 files changed, 27 insertions, 15 deletions

diff --git a/src/dev/ns_gige.cc b/src/dev/ns_gige.cc
index eb6eb6353..4dc4aeae9 100644
--- a/src/dev/ns_gige.cc
+++ b/src/dev/ns_gige.cc
@@ -50,6 +50,12 @@
 #include "params/NSGigE.hh"
 #include "sim/system.hh"
 
+// clang complains about std::set being overloaded with Packet::set if
+// we open up the entire namespace std
+using std::min;
+using std::ostream;
+using std::string;
+
 const char *NsRxStateStrings[] =
 {
     "rxIdle",
@@ -81,7 +87,6 @@ const char *NsDmaState[] =
     "dmaWriteWaiting"
 };
 
-using namespace std;
 using namespace Net;
 using namespace TheISA;
 
@@ -479,12 +484,12 @@ NSGigE::write(PacketPtr pkt)
 // all these #if 0's are because i don't THINK the kernel needs to
 // have these implemented. if there is a problem relating to one of
 // these, you may need to add functionality in.
+
+// grouped together and #if 0'ed to avoid empty if body and make clang happy
+#if 0
             if (reg & CFGR_TBI_EN) ;
             if (reg & CFGR_MODE_1000) ;
 
-            if (reg & CFGR_AUTO_1000)
-                panic("CFGR_AUTO_1000 not implemented!\n");
-
             if (reg & CFGR_PINT_DUPSTS ||
                 reg & CFGR_PINT_LNKSTS ||
                 reg & CFGR_PINT_SPDSTS)
@@ -494,22 +499,11 @@ NSGigE::write(PacketPtr pkt)
             if (reg & CFGR_MRM_DIS) ;
             if (reg & CFGR_MWI_DIS) ;
 
-            if (reg & CFGR_T64ADDR) ;
-            // panic("CFGR_T64ADDR is read only register!\n");
-
-            if (reg & CFGR_PCI64_DET)
-                panic("CFGR_PCI64_DET is read only register!\n");
-
             if (reg & CFGR_DATA64_EN) ;
             if (reg & CFGR_M64ADDR) ;
             if (reg & CFGR_PHY_RST) ;
             if (reg & CFGR_PHY_DIS) ;
 
-            if (reg & CFGR_EXTSTS_EN)
-                extstsEnable = true;
-            else
-                extstsEnable = false;
-
             if (reg & CFGR_REQALG) ;
             if (reg & CFGR_SB) ;
             if (reg & CFGR_POW) ;
@@ -518,6 +512,20 @@ NSGigE::write(PacketPtr pkt)
             if (reg & CFGR_BROM_DIS) ;
             if (reg & CFGR_EXT_125) ;
             if (reg & CFGR_BEM) ;
+
+            if (reg & CFGR_T64ADDR) ;
+            // panic("CFGR_T64ADDR is read only register!\n");
+#endif
+            if (reg & CFGR_AUTO_1000)
+                panic("CFGR_AUTO_1000 not implemented!\n");
+
+            if (reg & CFGR_PCI64_DET)
+                panic("CFGR_PCI64_DET is read only register!\n");
+
+            if (reg & CFGR_EXTSTS_EN)
+                extstsEnable = true;
+            else
+                extstsEnable = false;
             break;
 
           case MEAR:
@@ -541,9 +549,13 @@ NSGigE::write(PacketPtr pkt)
             eepromClk = reg & MEAR_EECLK;
 
             // since phy is completely faked, MEAR_MD* don't matter
+
+// grouped together and #if 0'ed to avoid empty if body and make clang happy
+#if 0
             if (reg & MEAR_MDIO) ;
             if (reg & MEAR_MDDIR) ;
             if (reg & MEAR_MDC) ;
+#endif
             break;
 
           case PTSCR: