misc: Generalize GDB single stepping.

The new single stepping implementation for x86 doesn't rely on any ISA
specific properties or functionality. This change pulls out the per ISA
implementation of those functions and promotes the X86 implementation to the
base class.

One drawback of that implementation is that the CPU might stop on an
instruction twice if it's affected by both breakpoints and single stepping.
While that might be a little surprising, it's harmless and would only happen
under somewhat unlikely circumstances.

2 files changed, 0 insertions, 51 deletions

diff --git a/src/arch/mips/remote_gdb.cc b/src/arch/mips/remote_gdb.cc
index 9c944fc59..a7bde8ba6 100644
--- a/src/arch/mips/remote_gdb.cc
+++ b/src/arch/mips/remote_gdb.cc
@@ -235,47 +235,3 @@ RemoteGDB::setregs()
     context->setFloatRegBits(FLOATREG_FIR,
         gdbregs.regs32[GdbIntRegs + GdbFloatArchRegs + 1]);
 }
-
-void
-RemoteGDB::clearSingleStep()
-{
-    DPRINTF(GDBMisc, "clearSingleStep bt_addr=%#x nt_addr=%#x\n",
-            takenBkpt, notTakenBkpt);
-
-    if (takenBkpt != 0)
-        clearTempBreakpoint(takenBkpt);
-
-    if (notTakenBkpt != 0)
-        clearTempBreakpoint(notTakenBkpt);
-}
-
-void
-RemoteGDB::setSingleStep()
-{
-    PCState pc = context->pcState();
-    PCState bpc;
-    bool set_bt = false;
-
-    // User was stopped at pc, e.g. the instruction at pc was not
-    // executed.
-    MachInst inst = read<MachInst>(pc.pc());
-    StaticInstPtr si = context->getDecoderPtr()->decode(inst, pc.pc());
-    if (si->hasBranchTarget(pc, context, bpc)) {
-        // Don't bother setting a breakpoint on the taken branch if it
-        // is the same as the next npc
-        if (bpc.npc() != pc.nnpc())
-            set_bt = true;
-    }
-
-    DPRINTF(GDBMisc, "setSingleStep bt_addr=%#x nt_addr=%#x\n",
-            takenBkpt, notTakenBkpt);
-
-    notTakenBkpt = pc.nnpc();
-    setTempBreakpoint(notTakenBkpt);
-
-    if (set_bt) {
-        takenBkpt = bpc.npc();
-        setTempBreakpoint(takenBkpt);
-    }
-}
-
diff --git a/src/arch/mips/remote_gdb.hh b/src/arch/mips/remote_gdb.hh
index 157276dcf..8d113eb99 100644
--- a/src/arch/mips/remote_gdb.hh
+++ b/src/arch/mips/remote_gdb.hh
@@ -54,10 +54,6 @@ namespace MipsISA
 
     class RemoteGDB : public BaseRemoteGDB
     {
-      protected:
-        Addr notTakenBkpt;
-        Addr takenBkpt;
-
       public:
         RemoteGDB(System *_system, ThreadContext *tc);
 
@@ -66,9 +62,6 @@ namespace MipsISA
 
         void getregs();
         void setregs();
-
-        void clearSingleStep();
-        void setSingleStep();
     };
 }