arch: Remove "process()" from the Decoder interface.

This method was only ever an implementation detail on ARM and x86, the
only places it actually did anything. Remove it from the other decoders,
and also make it protected on x86 to remove confusion.

Change-Id: I3a719648039c1edfbc2bd044f0a21c8983b249f5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52075
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/mips/decoder.hh

@@ -55,11 +55,6 @@ class Decoder : public InstDecoder
     Decoder(ISA* isa = nullptr) : InstDecoder(&machInst)
     {}
 
-    void
-    process()
-    {
-    }
-
     //Use this to give data to the decoder. This should be used
     //when there is control flow.
     void

src/arch/power/decoder.hh

@@ -52,11 +52,6 @@ class Decoder : public InstDecoder
   public:
     Decoder(ISA* isa=nullptr) : InstDecoder(&emi) {}
 
-    void
-    process()
-    {
-    }
-
     // Use this to give data to the predecoder. This should be used
     // when there is control flow.
     void

src/arch/riscv/decoder.hh

@@ -67,7 +67,6 @@ class Decoder : public InstDecoder
   public:
     Decoder(ISA* isa=nullptr) : InstDecoder(&machInst) { reset(); }
 
-    void process() {}
     void reset() override;
 
     inline bool compressed(ExtMachInst inst) { return (inst & 0x3) < 0x3; }

src/arch/sparc/decoder.hh

@@ -54,8 +54,6 @@ class Decoder : public InstDecoder
     Decoder(ISA* isa=nullptr) : InstDecoder(&machInst), asi(0)
     {}
 
-    void process() {}
-
     // Use this to give data to the predecoder. This should be used
     // when there is control flow.
     void

src/arch/x86/decoder.hh

@@ -250,6 +250,8 @@ class Decoder : public InstDecoder
     /// @retval A pointer to the corresponding StaticInst object.
     StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
 
+    void process();
+
   public:
     Decoder(ISA *isa=nullptr) : InstDecoder(&fetchChunk)
     {
@@ -309,8 +311,6 @@ class Decoder : public InstDecoder
         state = ResetState;
     }
 
-    void process();
-
     // Use this to give data to the decoder. This should be used
     // when there is control flow.
     void