1 files changed, 57 insertions, 1 deletions

diff --git a/llvm/tools/llvm-readobj/ObjDumper.h b/llvm/tools/llvm-readobj/ObjDumper.h
index a09a243d381e..292efd2ae350 100644
--- a/llvm/tools/llvm-readobj/ObjDumper.h
+++ b/llvm/tools/llvm-readobj/ObjDumper.h
@@ -9,9 +9,14 @@
 #ifndef LLVM_TOOLS_LLVM_READOBJ_OBJDUMPER_H
 #define LLVM_TOOLS_LLVM_READOBJ_OBJDUMPER_H
 
+#include <functional>
 #include <memory>
 #include <system_error>
 
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/CommandLine.h"
@@ -25,7 +30,7 @@ class COFFImportFile;
 class ObjectFile;
 class XCOFFObjectFile;
 class ELFObjectFileBase;
-}
+} // namespace object
 namespace codeview {
 class GlobalTypeTableBuilder;
 class MergingTypeTableBuilder;
@@ -33,6 +38,33 @@ class MergingTypeTableBuilder;
 
 class ScopedPrinter;
 
+// Comparator to compare symbols.
+// Usage: the caller registers predicates (i.e., how to compare the symbols) by
+// calling addPredicate(). The order in which predicates are registered is also
+// their priority.
+class SymbolComparator {
+public:
+  using CompPredicate =
+      std::function<bool(object::SymbolRef, object::SymbolRef)>;
+
+  // Each Obj format has a slightly different way of retrieving a symbol's info
+  // So we defer the predicate's impl to each format.
+  void addPredicate(CompPredicate Pred) { Predicates.push_back(Pred); }
+
+  bool operator()(object::SymbolRef LHS, object::SymbolRef RHS) {
+    for (CompPredicate Pred : Predicates) {
+      if (Pred(LHS, RHS))
+        return true;
+      if (Pred(RHS, LHS))
+        return false;
+    }
+    return false;
+  }
+
+private:
+  SmallVector<CompPredicate, 2> Predicates;
+};
+
 class ObjDumper {
 public:
   ObjDumper(ScopedPrinter &Writer, StringRef ObjName);
@@ -52,6 +84,17 @@ public:
     if (PrintDynamicSymbols)
       printDynamicSymbols();
   }
+  virtual void printSymbols(bool PrintSymbols, bool PrintDynamicSymbols,
+                            llvm::Optional<SymbolComparator> SymComp) {
+    if (SymComp) {
+      if (PrintSymbols)
+        printSymbols(SymComp);
+      if (PrintDynamicSymbols)
+        printDynamicSymbols(SymComp);
+    } else {
+      printSymbols(PrintSymbols, PrintDynamicSymbols);
+    }
+  }
   virtual void printProgramHeaders(bool PrintProgramHeaders,
                                    cl::boolOrDefault PrintSectionMapping) {
     if (PrintProgramHeaders)
@@ -62,6 +105,17 @@ public:
 
   virtual void printUnwindInfo() = 0;
 
+  // Symbol comparison functions.
+  virtual bool canCompareSymbols() const { return false; }
+  virtual bool compareSymbolsByName(object::SymbolRef LHS,
+                                    object::SymbolRef RHS) const {
+    return true;
+  }
+  virtual bool compareSymbolsByType(object::SymbolRef LHS,
+                                    object::SymbolRef RHS) const {
+    return true;
+  }
+
   // Only implemented for ELF at this time.
   virtual void printDependentLibs() {}
   virtual void printDynamicRelocations() { }
@@ -133,7 +187,9 @@ protected:
 
 private:
   virtual void printSymbols() {}
+  virtual void printSymbols(llvm::Optional<SymbolComparator> Comp) {}
   virtual void printDynamicSymbols() {}
+  virtual void printDynamicSymbols(llvm::Optional<SymbolComparator> Comp) {}
   virtual void printProgramHeaders() {}
   virtual void printSectionMapping() {}