arch: Make some internal decode methods protected.

These methods aren't used outside of the decoder and the decode cache,
so they don't need to be public.

Change-Id: Ifdaf318995f1bb0a75b390bd1c5fde1211c66e62
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40102
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>

src/arch/arm/decoder.hh

@@ -82,6 +82,7 @@ class Decoder : public InstDecoder
 
     /// A cache of decoded instruction objects.
     static GenericISA::BasicDecodeCache<Decoder, ExtMachInst> defaultCache;
+    friend class GenericISA::BasicDecodeCache<Decoder, ExtMachInst>;
 
     /**
      * Pre-decode an instruction from the current state of the
@@ -95,6 +96,38 @@ class Decoder : public InstDecoder
      */
     void consumeBytes(int numBytes);
 
+    /**
+     * Decode a machine instruction without calling the cache.
+     *
+     * @note The implementation of this method is generated by the ISA
+     * parser script.
+     *
+     * @warn This method takes a pre-decoded instruction as its
+     * argument. It should typically not be called directly.
+     *
+     * @param mach_inst The binary instruction to decode.
+     * @retval A pointer to the corresponding StaticInst object.
+     */
+    StaticInstPtr decodeInst(ExtMachInst mach_inst);
+
+    /**
+     * Decode a pre-decoded machine instruction.
+     *
+     * @warn This method takes a pre-decoded instruction as its
+     * argument. It should typically not be called directly.
+     *
+     * @param mach_inst A pre-decoded instruction
+     * @retval A pointer to the corresponding StaticInst object.
+     */
+    StaticInstPtr
+    decode(ExtMachInst mach_inst, Addr addr)
+    {
+        StaticInstPtr si = defaultCache.decode(this, mach_inst, addr);
+        DPRINTF(Decode, "Decode: Decoded %s instruction: %#x\n",
+                si->getName(), mach_inst);
+        return si;
+    }
+
   public: // Decoder API
     Decoder(ISA* isa = nullptr);
 
@@ -161,38 +194,6 @@ class Decoder : public InstDecoder
      */
     StaticInstPtr decode(ArmISA::PCState &pc);
 
-    /**
-     * Decode a pre-decoded machine instruction.
-     *
-     * @warn This method takes a pre-decoded instruction as its
-     * argument. It should typically not be called directly.
-     *
-     * @param mach_inst A pre-decoded instruction
-     * @retval A pointer to the corresponding StaticInst object.
-     */
-    StaticInstPtr
-    decode(ExtMachInst mach_inst, Addr addr)
-    {
-        StaticInstPtr si = defaultCache.decode(this, mach_inst, addr);
-        DPRINTF(Decode, "Decode: Decoded %s instruction: %#x\n",
-                si->getName(), mach_inst);
-        return si;
-    }
-
-    /**
-     * Decode a machine instruction without calling the cache.
-     *
-     * @note The implementation of this method is generated by the ISA
-     * parser script.
-     *
-     * @warn This method takes a pre-decoded instruction as its
-     * argument. It should typically not be called directly.
-     *
-     * @param mach_inst The binary instruction to decode.
-     * @retval A pointer to the corresponding StaticInst object.
-     */
-    StaticInstPtr decodeInst(ExtMachInst mach_inst);
-
     /**
      * Take over the state from an old decoder when switching CPUs.
      *

src/arch/mips/decoder.hh

@@ -89,8 +89,8 @@ class Decoder : public InstDecoder
   protected:
     /// A cache of decoded instruction objects.
     static GenericISA::BasicDecodeCache<Decoder, ExtMachInst> defaultCache;
+    friend class GenericISA::BasicDecodeCache<Decoder, ExtMachInst>;
 
-  public:
     StaticInstPtr decodeInst(ExtMachInst mach_inst);
 
     /// Decode a machine instruction.
@@ -105,6 +105,7 @@ class Decoder : public InstDecoder
         return si;
     }
 
+  public:
     StaticInstPtr
     decode(MipsISA::PCState &nextPC)
     {

src/arch/power/decoder.hh

@@ -96,8 +96,8 @@ class Decoder : public InstDecoder
   protected:
     /// A cache of decoded instruction objects.
     static GenericISA::BasicDecodeCache<Decoder, ExtMachInst> defaultCache;
+    friend class GenericISA::BasicDecodeCache<Decoder, ExtMachInst>;
 
-  public:
     StaticInstPtr decodeInst(ExtMachInst mach_inst);
 
     /// Decode a machine instruction.
@@ -112,6 +112,7 @@ class Decoder : public InstDecoder
         return si;
     }
 
+  public:
     StaticInstPtr
     decode(PowerISA::PCState &nextPC)
     {

src/arch/riscv/decoder.hh

@@ -56,6 +56,13 @@ class Decoder : public InstDecoder
     ExtMachInst emi;
     bool instDone;
 
+    StaticInstPtr decodeInst(ExtMachInst mach_inst);
+
+    /// Decode a machine instruction.
+    /// @param mach_inst The binary instruction to decode.
+    /// @retval A pointer to the corresponding StaticInst object.
+    StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
+
   public:
     Decoder(ISA* isa=nullptr) { reset(); }
 
@@ -72,13 +79,6 @@ class Decoder : public InstDecoder
     bool instReady() { return instDone; }
     void takeOverFrom(Decoder *old) {}
 
-    StaticInstPtr decodeInst(ExtMachInst mach_inst);
-
-    /// Decode a machine instruction.
-    /// @param mach_inst The binary instruction to decode.
-    /// @retval A pointer to the corresponding StaticInst object.
-    StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
-
     StaticInstPtr decode(RiscvISA::PCState &nextPC);
 };
 

src/arch/sparc/decoder.hh

@@ -103,8 +103,8 @@ class Decoder : public InstDecoder
   protected:
     /// A cache of decoded instruction objects.
     static GenericISA::BasicDecodeCache<Decoder, ExtMachInst> defaultCache;
+    friend class GenericISA::BasicDecodeCache<Decoder, ExtMachInst>;
 
-  public:
     StaticInstPtr decodeInst(ExtMachInst mach_inst);
 
     /// Decode a machine instruction.
@@ -119,6 +119,7 @@ class Decoder : public InstDecoder
         return si;
     }
 
+  public:
     StaticInstPtr
     decode(SparcISA::PCState &nextPC)
     {

src/arch/x86/decoder.hh

@@ -241,6 +241,13 @@ class Decoder : public InstDecoder
             CacheKey, DecodeCache::InstMap<ExtMachInst> *> InstCacheMap;
     static InstCacheMap instCacheMap;
 
+    StaticInstPtr decodeInst(ExtMachInst mach_inst);
+
+    /// Decode a machine instruction.
+    /// @param mach_inst The binary instruction to decode.
+    /// @retval A pointer to the corresponding StaticInst object.
+    StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
+
   public:
     Decoder(ISA *isa=nullptr)
     {
@@ -328,12 +335,6 @@ class Decoder : public InstDecoder
     }
 
   public:
-    StaticInstPtr decodeInst(ExtMachInst mach_inst);
-
-    /// Decode a machine instruction.
-    /// @param mach_inst The binary instruction to decode.
-    /// @retval A pointer to the corresponding StaticInst object.
-    StaticInstPtr decode(ExtMachInst mach_inst, Addr addr);
     StaticInstPtr decode(X86ISA::PCState &nextPC);
 
     StaticInstPtr fetchRomMicroop(