mem-ruby: Standardize Bloom Filter deletion support

Standard Bloom Filters do not support element deletion by default,
however some variants do. Allow calling the unset function with
all filters, and do nothing by default.

Change-Id: Icf4b0f8b997c4c70fa714b2576474810275db78b
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18730
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/ruby/filters/AbstractBloomFilter.hh

@@ -40,7 +40,15 @@ class AbstractBloomFilter
     virtual void clear() = 0;
     virtual void merge(AbstractBloomFilter * other_filter) = 0;
     virtual void set(Addr addr) = 0;
-    virtual void unset(Addr addr) = 0;
+
+    /**
+     * Perform the filter specific function to clear the corresponding
+     * entries (can be multiple) of an address. By default a bloom
+     * filter does not support element deletion.
+     *
+     * @param addr The address being parsed.
+     */
+    virtual void unset(Addr addr) {};
 
     virtual bool isSet(Addr addr) = 0;
     virtual int getCount(Addr addr) = 0;

src/mem/ruby/filters/BlockBloomFilter.hh

@@ -44,7 +44,7 @@ class BlockBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
+    void unset(Addr addr) override;
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/BulkBloomFilter.cc

@@ -91,12 +91,6 @@ BulkBloomFilter::set(Addr addr)
     m_filter[c1] = 1;
 }
 
-void
-BulkBloomFilter::unset(Addr addr)
-{
-    // not used
-}
-
 bool
 BulkBloomFilter::isSet(Addr addr)
 {

src/mem/ruby/filters/BulkBloomFilter.hh

@@ -44,7 +44,6 @@ class BulkBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/H3BloomFilter.cc

@@ -423,12 +423,6 @@ H3BloomFilter::set(Addr addr)
     }
 }
 
-void
-H3BloomFilter::unset(Addr addr)
-{
-    panic("ERROR: Unset should never be called in a Bloom filter");
-}
-
 bool
 H3BloomFilter::isSet(Addr addr)
 {

src/mem/ruby/filters/H3BloomFilter.hh

@@ -44,7 +44,6 @@ class H3BloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/LSB_CountingBloomFilter.hh

@@ -44,7 +44,7 @@ class LSB_CountingBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
+    void unset(Addr addr) override;
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/MultiBitSelBloomFilter.cc

@@ -78,12 +78,6 @@ MultiBitSelBloomFilter::set(Addr addr)
     }
 }
 
-void
-MultiBitSelBloomFilter::unset(Addr addr)
-{
-    panic("ERROR: Unset should never be called in a Bloom filter");
-}
-
 bool
 MultiBitSelBloomFilter::isSet(Addr addr)
 {

src/mem/ruby/filters/MultiBitSelBloomFilter.hh

@@ -46,7 +46,6 @@ class MultiBitSelBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/MultiGrainBloomFilter.cc

@@ -81,12 +81,6 @@ MultiGrainBloomFilter::set(Addr addr)
 
 }
 
-void
-MultiGrainBloomFilter::unset(Addr addr)
-{
-    // not used
-}
-
 bool
 MultiGrainBloomFilter::isSet(Addr addr)
 {

src/mem/ruby/filters/MultiGrainBloomFilter.hh

@@ -44,7 +44,6 @@ class MultiGrainBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
 
     bool isSet(Addr addr);
     int getCount(Addr addr);

src/mem/ruby/filters/NonCountingBloomFilter.hh

@@ -44,7 +44,7 @@ class NonCountingBloomFilter : public AbstractBloomFilter
     void clear();
     void merge(AbstractBloomFilter * other_filter);
     void set(Addr addr);
-    void unset(Addr addr);
+    void unset(Addr addr) override;
 
     bool isSet(Addr addr);
     int getCount(Addr addr);