Filter out consecutive equal DWARF lines

src/ConseqEquivFilter.cpp

@@ -0,0 +1,49 @@
+#include "ConseqEquivFilter.hpp"
+
+using namespace std;
+
+ConseqEquivFilter::ConseqEquivFilter() {}
+
+static bool equiv_reg(
+        const SimpleDwarf::DwRegister& r1,
+        const SimpleDwarf::DwRegister& r2)
+{
+    return r1.type == r2.type
+        && r1.offset == r2.offset
+        && r1.reg == r2.reg;
+}
+
+static bool equiv_row(
+        const SimpleDwarf::DwRow& r1,
+        const SimpleDwarf::DwRow& r2)
+{
+    return r1.ip == r2.ip
+        && equiv_reg(r1.cfa, r2.cfa)
+        && equiv_reg(r1.rbp, r2.rbp)
+        && equiv_reg(r1.ra, r2.ra);
+}
+
+SimpleDwarf ConseqEquivFilter::do_apply(const SimpleDwarf& dw) const {
+    SimpleDwarf out;
+
+    for(const auto& fde: dw.fde_list) {
+        out.fde_list.push_back(SimpleDwarf::Fde());
+        SimpleDwarf::Fde& cur_fde = out.fde_list.back();
+        cur_fde.fde_offset = fde.fde_offset;
+        cur_fde.beg_ip = fde.beg_ip;
+        cur_fde.end_ip = fde.end_ip;
+
+        if(fde.rows.empty())
+            continue;
+
+        cur_fde.rows.push_back(fde.rows.front());
+        for(size_t pos=1; pos < fde.rows.size(); ++pos) {
+            const auto& row = fde.rows[pos];
+            if(!equiv_row(row, cur_fde.rows.back())) {
+                cur_fde.rows.push_back(row);
+            }
+        }
+    }
+
+    return out;
+}

src/ConseqEquivFilter.hpp

@@ -0,0 +1,16 @@
+/** SimpleDwarfFilter to keep a unique Dwarf row for each group of consecutive
+ * lines that are equivalent, that is, that share the same considered
+ * registers' values. */
+
+#pragma once
+
+#include "SimpleDwarf.hpp"
+#include "SimpleDwarfFilter.hpp"
+
+class ConseqEquivFilter: public SimpleDwarfFilter {
+    public:
+        ConseqEquivFilter();
+
+    private:
+        SimpleDwarf do_apply(const SimpleDwarf& dw) const;
+};

src/Makefile

@@ -11,6 +11,7 @@ OBJS=\
 	PcListReader.o \
 	SimpleDwarfFilter.o \
 	PcHoleFiller.o \
+	ConseqEquivFilter.o \
 	settings.o \
 	main.o
 

src/main.cpp

@@ -8,6 +8,7 @@
 #include "DwarfReader.hpp"
 #include "CodeGenerator.hpp"
 #include "PcHoleFiller.hpp"
+#include "ConseqEquivFilter.hpp"
 
 #include "settings.hpp"
 
@@ -94,7 +95,9 @@ int main(int argc, char** argv) {
     SimpleDwarf parsed_dwarf = DwarfReader(opts.elf_path).read();
 
     SimpleDwarf filtered_dwarf =
-        PcHoleFiller()(parsed_dwarf);
+        PcHoleFiller()(
+        ConseqEquivFilter()(
+            parsed_dwarf));
 
     CodeGenerator code_gen(
             filtered_dwarf,