Decoder: Remove the thread context get/set from the decoder.

This interface is no longer used, and getting rid of it simplifies the
decoders and code that sets up the decoders. The thread context had been used
to read architectural state which was used to contextualize the instruction
memory as it came in. That was changed so that the state is now sent to the
decoders to keep locally if/when it changes. That's significantly more
efficient.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

src/arch/alpha/decoder.hh

@@ -36,36 +36,20 @@
 #include "cpu/static_inst.hh"
 #include "sim/full_system.hh"
 
-class ThreadContext;
-
 namespace AlphaISA
 {
 
 class Decoder
 {
   protected:
-    ThreadContext *tc;
-
     // The extended machine instruction being generated
     ExtMachInst ext_inst;
     bool instDone;
 
   public:
-    Decoder(ThreadContext * _tc) : tc(_tc), instDone(false)
+    Decoder() : instDone(false)
     {}
 
-    ThreadContext *
-    getTC()
-    {
-        return tc;
-    }
-
-    void
-    setTC(ThreadContext * _tc)
-    {
-        tc = _tc;
-    }
-
     void
     process()
     { }

src/arch/arm/decoder.cc

@@ -32,7 +32,6 @@
 #include "arch/arm/isa_traits.hh"
 #include "arch/arm/utility.hh"
 #include "base/trace.hh"
-#include "cpu/thread_context.hh"
 #include "debug/Decoder.hh"
 
 namespace ArmISA

src/arch/arm/decoder.hh

@@ -39,15 +39,12 @@
 #include "base/types.hh"
 #include "cpu/static_inst.hh"
 
-class ThreadContext;
-
 namespace ArmISA
 {
 
 class Decoder
 {
   protected:
-    ThreadContext * tc;
     //The extended machine instruction being generated
     ExtMachInst emi;
     MachInst data;
@@ -72,23 +69,11 @@ class Decoder
         foundIt = false;
     }
 
-    Decoder(ThreadContext * _tc) : tc(_tc), data(0),
-        fpscrLen(0), fpscrStride(0)
+    Decoder() : data(0), fpscrLen(0), fpscrStride(0)
     {
         reset();
     }
 
-    ThreadContext * getTC()
-    {
-        return tc;
-    }
-
-    void
-    setTC(ThreadContext * _tc)
-    {
-        tc = _tc;
-    }
-
     void process();
 
     //Use this to give data to the decoder. This should be used

src/arch/arm/isa.cc

@@ -381,7 +381,7 @@ ISA::setMiscReg(int misc_reg, const MiscReg &val, ThreadContext *tc)
                 fpscrMask.n = ones;
                 newVal = (newVal & (uint32_t)fpscrMask) |
                          (miscRegs[MISCREG_FPSCR] & ~(uint32_t)fpscrMask);
-                tc->getDecodePtr()->setContext(newVal);
+                tc->getDecoderPtr()->setContext(newVal);
             }
             break;
           case MISCREG_CPSR_Q:

src/arch/mips/decoder.hh

@@ -37,34 +37,20 @@
 #include "base/types.hh"
 #include "cpu/static_inst.hh"
 
-class ThreadContext;
-
 namespace MipsISA
 {
 
 class Decoder
 {
   protected:
-    ThreadContext * tc;
     //The extended machine instruction being generated
     ExtMachInst emi;
     bool instDone;
 
   public:
-    Decoder(ThreadContext * _tc) : tc(_tc), instDone(false)
+    Decoder() : instDone(false)
     {}
 
-    ThreadContext *getTC()
-    {
-        return tc;
-    }
-
-    void
-    setTC(ThreadContext *_tc)
-    {
-        tc = _tc;
-    }
-
     void
     process()
     {

src/arch/power/decoder.hh

@@ -35,37 +35,21 @@
 #include "arch/types.hh"
 #include "cpu/static_inst.hh"
 
-class ThreadContext;
-
 namespace PowerISA
 {
 
 class Decoder
 {
   protected:
-    ThreadContext * tc;
-
     // The extended machine instruction being generated
     ExtMachInst emi;
     bool instDone;
 
   public:
-    Decoder(ThreadContext * _tc) : tc(_tc), instDone(false)
+    Decoder() : instDone(false)
     {
     }
 
-    ThreadContext *
-    getTC()
-    {
-        return tc;
-    }
-
-    void
-    setTC(ThreadContext * _tc)
-    {
-        tc = _tc;
-    }
-
     void
     process()
     {

src/arch/sparc/decoder.hh

@@ -35,9 +35,6 @@
 #include "arch/sparc/registers.hh"
 #include "arch/types.hh"
 #include "cpu/static_inst.hh"
-#include "cpu/thread_context.hh"
-
-class ThreadContext;
 
 namespace SparcISA
 {
@@ -45,28 +42,15 @@ namespace SparcISA
 class Decoder
 {
   protected:
-    ThreadContext * tc;
     // The extended machine instruction being generated
     ExtMachInst emi;
     bool instDone;
     MiscReg asi;
 
   public:
-    Decoder(ThreadContext * _tc) : tc(_tc), instDone(false), asi(0)
+    Decoder() : instDone(false), asi(0)
     {}
 
-    ThreadContext *
-    getTC()
-    {
-        return tc;
-    }
-
-    void
-    setTC(ThreadContext * _tc)
-    {
-        tc = _tc;
-    }
-
     void process() {}
 
     void

src/arch/sparc/isa.cc

@@ -29,6 +29,7 @@
  */
 
 #include "arch/sparc/asi.hh"
+#include "arch/sparc/decoder.hh"
 #include "arch/sparc/isa.hh"
 #include "base/bitfield.hh"
 #include "base/trace.hh"
@@ -550,7 +551,7 @@ ISA::setMiscReg(int miscReg, MiscReg val, ThreadContext * tc)
 
     switch (miscReg) {
       case MISCREG_ASI:
-        tc->getDecodePtr()->setContext(val);
+        tc->getDecoderPtr()->setContext(val);
         break;
       case MISCREG_STICK:
       case MISCREG_TICK:

src/arch/x86/decoder.cc

@@ -33,7 +33,6 @@
 #include "base/misc.hh"
 #include "base/trace.hh"
 #include "base/types.hh"
-#include "cpu/thread_context.hh"
 #include "debug/Decoder.hh"
 
 namespace X86ISA

src/arch/x86/decoder.hh

@@ -44,8 +44,6 @@
 #include "cpu/static_inst.hh"
 #include "debug/Decoder.hh"
 
-class ThreadContext;
-
 namespace X86ISA
 {
 
@@ -72,7 +70,6 @@ class Decoder
 
     static InstBytes dummy;
 
-    ThreadContext * tc;
     //The bytes to be predecoded
     MachInst fetchChunk;
     InstBytes *instBytes;
@@ -205,8 +202,7 @@ class Decoder
     static InstCacheMap instCacheMap;
 
   public:
-    Decoder(ThreadContext * _tc) :
-        tc(_tc), basePC(0), origPC(0), offset(0),
+    Decoder() : basePC(0), origPC(0), offset(0),
         outOfBytes(true), instDone(false),
         state(ResetState)
     {
@@ -259,16 +255,6 @@ class Decoder
         state = ResetState;
     }
 
-    ThreadContext * getTC()
-    {
-        return tc;
-    }
-
-    void setTC(ThreadContext * _tc)
-    {
-        tc = _tc;
-    }
-
     void process();
 
     //Use this to give data to the decoder. This should be used

src/cpu/checker/cpu_impl.hh

@@ -306,7 +306,6 @@ Checker<Impl>::verify(DynInstPtr &completed_inst)
                     StaticInstPtr instPtr = NULL;
 
                     //Predecode, ie bundle up an ExtMachInst
-                    thread->decoder.setTC(thread->getTC());
                     //If more fetch data is needed, pass it in.
                     Addr fetchPC = (pcState.instAddr() & PCMask) + fetchOffset;
                     thread->decoder.moreBytes(pcState, fetchPC, machInst);

src/cpu/inorder/resources/fetch_unit.cc

@@ -59,7 +59,7 @@ FetchUnit::FetchUnit(string res_name, int res_id, int res_width,
       instSize(sizeof(TheISA::MachInst)), fetchBuffSize(params->fetchBuffSize)
 {
     for (int tid = 0; tid < MaxThreads; tid++)
-        decoder[tid] = new Decoder(NULL);
+        decoder[tid] = new Decoder;
 }
 
 FetchUnit::~FetchUnit()
@@ -109,7 +109,6 @@ FetchUnit::createMachInst(std::list<FetchBlock*>::iterator fetch_it,
     MachInst mach_inst =
         TheISA::gtoh(fetchInsts[fetch_offset]);
 
-    decoder[tid]->setTC(cpu->thread[tid]->getTC());
     decoder[tid]->moreBytes(instPC, inst->instAddr(), mach_inst);
     assert(decoder[tid]->instReady());
     inst->setStaticInst(decoder[tid]->decode(instPC));

src/cpu/legiontrace.cc

@@ -422,7 +422,6 @@ Trace::LegionTraceRecord::dump()
                          << endl;
 
                     TheISA::Decoder *decoder = thread->getDecoderPtr();
-                    decoder->setTC(thread);
                     decoder->moreBytes(m5Pc, m5Pc, shared_data->instruction);
 
                     assert(decoder->instReady());

src/cpu/o3/fetch_impl.hh

@@ -134,7 +134,7 @@ DefaultFetch<Impl>::DefaultFetch(O3CPU *_cpu, DerivO3CPUParams *params)
 
     for (int i = 0; i < Impl::MaxThreads; i++) {
         cacheData[i] = NULL;
-        decoder[i] = new TheISA::Decoder(NULL);
+        decoder[i] = new TheISA::Decoder;
     }
 }
 
@@ -1225,9 +1225,8 @@ DefaultFetch<Impl>::fetch(bool &status_change)
                 if (blkOffset >= numInsts)
                     break;
             }
-            MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
 
-            decoder[tid]->setTC(cpu->thread[tid]->getTC());
+            MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
             decoder[tid]->moreBytes(thisPC, fetchAddr, inst);
 
             if (decoder[tid]->needMoreBytes()) {

src/cpu/simple/base.cc

@@ -380,8 +380,6 @@ BaseSimpleCPU::preExecute()
         TheISA::Decoder *decoder = &(thread->decoder);
 
         //Predecode, ie bundle up an ExtMachInst
-        //This should go away once the constructor can be set up properly
-        decoder->setTC(thread->getTC());
         //If more fetch data is needed, pass it in.
         Addr fetchPC = (pcState.instAddr() & PCMask) + fetchOffset;
         //if(decoder->needMoreBytes())

src/cpu/simple_thread.cc

@@ -63,16 +63,16 @@ SimpleThread::SimpleThread(BaseCPU *_cpu, int _thread_num, System *_sys,
                            Process *_process, TheISA::TLB *_itb,
                            TheISA::TLB *_dtb)
     : ThreadState(_cpu, _thread_num, _process), system(_sys), itb(_itb),
-      dtb(_dtb), decoder(NULL)
+      dtb(_dtb)
 {
     clearArchRegs();
     tc = new ProxyThreadContext<SimpleThread>(this);
 }
+
 SimpleThread::SimpleThread(BaseCPU *_cpu, int _thread_num, System *_sys,
                            TheISA::TLB *_itb, TheISA::TLB *_dtb,
                            bool use_kernel_stats)
-    : ThreadState(_cpu, _thread_num, NULL), system(_sys), itb(_itb), dtb(_dtb),
-      decoder(NULL)
+    : ThreadState(_cpu, _thread_num, NULL), system(_sys), itb(_itb), dtb(_dtb)
 {
     tc = new ProxyThreadContext<SimpleThread>(this);
 
@@ -99,7 +99,7 @@ SimpleThread::SimpleThread(BaseCPU *_cpu, int _thread_num, System *_sys,
 }
 
 SimpleThread::SimpleThread()
-    : ThreadState(NULL, -1, NULL), decoder(NULL)
+    : ThreadState(NULL, -1, NULL)
 {
     tc = new ProxyThreadContext<SimpleThread>(this);
 }