mem-ruby: Finish implementing BloomFilter merge

Not all Bloom Filters had their union functionality implemented.
This change adds them.

Change-Id: I86af18d3c5eabd0da8280b57a88789b3af803c04
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18872
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/ruby/filters/AbstractBloomFilter.hh

@@ -76,8 +76,20 @@ class AbstractBloomFilter : public SimObject
         }
     }
 
-    /** Merges the contents of both filters into this'. */
-    virtual void merge(const AbstractBloomFilter* other) {}
+    /**
+     * Merges the contents of both filters into this' (Bloom Filter union).
+     * Both must have the same number of entries.
+     *
+     * @param other The other bloom filter to merge with.
+     */
+    virtual void
+    merge(const AbstractBloomFilter* other)
+    {
+        assert(filter.size() == other->filter.size());
+        for (int i = 0; i < filter.size(); ++i){
+            filter[i] |= other->filter[i];
+        }
+    }
 
     /**
      * Perform the filter specific function to set the corresponding

src/mem/ruby/filters/H3BloomFilter.cc

@@ -367,16 +367,6 @@ H3BloomFilter::~H3BloomFilter()
 {
 }
 
-void
-H3BloomFilter::merge(const AbstractBloomFilter *other)
-{
-    auto* cast_other = static_cast<const H3BloomFilter*>(other);
-    assert(filter.size() == cast_other->filter.size());
-    for (int i = 0; i < filter.size(); ++i){
-        filter[i] |= cast_other->filter[i];
-    }
-}
-
 void
 H3BloomFilter::set(Addr addr)
 {

src/mem/ruby/filters/H3BloomFilter.hh

@@ -43,7 +43,6 @@ class H3BloomFilter : public AbstractBloomFilter
     H3BloomFilter(const H3BloomFilterParams* p);
     ~H3BloomFilter();
 
-    void merge(const AbstractBloomFilter* other) override;
     void set(Addr addr) override;
     int getCount(Addr addr) const override;
 

src/mem/ruby/filters/LSB_CountingBloomFilter.cc

@@ -41,6 +41,20 @@ LSB_CountingBloomFilter::~LSB_CountingBloomFilter()
 {
 }
 
+void
+LSB_CountingBloomFilter::merge(const AbstractBloomFilter* other)
+{
+    auto* cast_other = static_cast<const LSB_CountingBloomFilter*>(other);
+    assert(filter.size() == cast_other->filter.size());
+    for (int i = 0; i < filter.size(); ++i){
+        if (filter[i] < maxValue - cast_other->filter[i]) {
+            filter[i] += cast_other->filter[i];
+        } else {
+            filter[i] = maxValue;
+        }
+    }
+}
+
 void
 LSB_CountingBloomFilter::set(Addr addr)
 {

src/mem/ruby/filters/LSB_CountingBloomFilter.hh

@@ -39,6 +39,7 @@ class LSB_CountingBloomFilter : public AbstractBloomFilter
     LSB_CountingBloomFilter(const LSB_CountingBloomFilterParams* p);
     ~LSB_CountingBloomFilter();
 
+    void merge(const AbstractBloomFilter* other) override;
     void set(Addr addr) override;
     void unset(Addr addr) override;
 

src/mem/ruby/filters/MultiBitSelBloomFilter.cc

@@ -46,16 +46,6 @@ MultiBitSelBloomFilter::~MultiBitSelBloomFilter()
 {
 }
 
-void
-MultiBitSelBloomFilter::merge(const AbstractBloomFilter *other)
-{
-    auto cast_other = static_cast<const MultiBitSelBloomFilter*>(other);
-    assert(filter.size() == cast_other->filter.size());
-    for (int i = 0; i < filter.size(); ++i){
-        filter[i] |= cast_other->filter[i];
-    }
-}
-
 void
 MultiBitSelBloomFilter::set(Addr addr)
 {

src/mem/ruby/filters/MultiBitSelBloomFilter.hh

@@ -39,7 +39,6 @@ class MultiBitSelBloomFilter : public AbstractBloomFilter
     MultiBitSelBloomFilter(const MultiBitSelBloomFilterParams* p);
     ~MultiBitSelBloomFilter();
 
-    void merge(const AbstractBloomFilter* other) override;
     void set(Addr addr) override;
     int getCount(Addr addr) const override;