Add source assignment in symbol nodes

include/eld/Script/Expression.h

@@ -331,6 +331,7 @@ class Symbol : public Expression {
   Expression *getRightExpression() const override { return nullptr; }
 
   mutable LDSymbol *ThisSymbol = nullptr;
+  const Assignment *SourceAssignment = nullptr;
 };
 
 //===----------------------------------------------------------------------===//

include/eld/Target/GNULDBackend.h

@@ -20,6 +20,7 @@
 #include "eld/Readers/ELFSection.h"
 #include "eld/Readers/SymDefReader.h"
 #include "eld/Script/Assignment.h"
+#include "eld/Script/Expression.h"
 #include "eld/Script/VersionScript.h"
 #include "eld/SymbolResolver/ResolveInfo.h"
 #include "eld/Target/ELFSegment.h"
@@ -824,6 +825,17 @@ class GNULDBackend {
 
   const ResolveInfo *findAbsolutePLT(ResolveInfo *I) const;
 
+  const Assignment *getLatestAssignment(llvm::StringRef SymName) {
+    auto it = SymbolNameToLatestAssignment.find(SymName);
+    if (it != SymbolNameToLatestAssignment.end())
+      return it->getValue();
+    return nullptr;
+  }
+
+  void updateLatestAssignment(llvm::StringRef SymName, const Assignment *A) {
+    SymbolNameToLatestAssignment[SymName] = A;
+  }
+
 protected:
   virtual int numReservedSegments() const { return m_NumReservedSegments; }
 
@@ -1132,6 +1144,8 @@ class GNULDBackend {
   bool m_NeedEhdr = false;
 
   bool m_NeedPhdr = false;
+
+  llvm::StringMap<const Assignment *> SymbolNameToLatestAssignment;
 };
 
 } // namespace eld

lib/Object/ObjectLinker.cpp

@@ -1716,6 +1716,7 @@ bool ObjectLinker::addScriptSymbols() {
     // If there is a relocation to this symbol, the symbols contained in the
     // assignment also need to be considered as part of the list of symbols
     // that will be live.
+    // FIXME: Duplicate redundant addAssignment!
     if (Symbol)
       ThisModule->addAssignment(Symbol->resolveInfo()->name(), AssignCmd);
   }

lib/Script/Assignment.cpp

@@ -222,6 +222,9 @@ bool Assignment::assign(Module &CurModule, const ELFSection *Section) {
     ThisSymbol->setScriptValueDefined();
   }
 
+  auto &Backend = CurModule.getBackend();
+  Backend.updateLatestAssignment(Name, this);
+
   if (CurModule.getPrinter()->traceAssignments())
     trace(llvm::outs());
   return true;

lib/Script/Expression.cpp

@@ -9,6 +9,7 @@
 #include "eld/Core/LinkerScript.h"
 #include "eld/Core/Module.h"
 #include "eld/Readers/ELFSection.h"
+#include "eld/Script/Assignment.h"
 #include "eld/Script/ScriptFile.h"
 #include "eld/Support/MsgHandling.h"
 #include "eld/Support/Utils.h"
@@ -133,10 +134,17 @@ bool Symbol::hasDot() const {
 }
 
 eld::Expected<uint64_t> Symbol::evalImpl() {
-
   if (!ThisSymbol)
     ThisSymbol = ThisModule.getNamePool().findSymbol(Name);
 
+  if (!SourceAssignment && ThisSymbol->resolveInfo()->isAbsolute()) {
+    auto &Backend = ThisModule.getBackend();
+    const auto *A = Backend.getLatestAssignment(Name);
+    if (!A)
+      A = ThisModule.getAssignmentForSymbol(Name);
+    SourceAssignment = A;
+  }
+
   if (!ThisSymbol || ThisSymbol->resolveInfo()->isUndef() ||
       ThisSymbol->resolveInfo()->isBitCode())
     return std::make_unique<plugin::DiagnosticEntry>(
@@ -152,6 +160,10 @@ eld::Expected<uint64_t> Symbol::evalImpl() {
            "using a symbol that points to a non allocatable section!");
     return Section->addr() + FragRef->getOutputOffset(ThisModule);
   }
+  if (hasDot())
+    return ThisSymbol->value();
+  if (SourceAssignment)
+    return SourceAssignment->value();
   return ThisSymbol->value();
 }
 

lib/Target/GNULDBackend.cpp

@@ -3100,6 +3100,7 @@ bool GNULDBackend::layout() {
     return false;
   }
 
+  // FIXME: Adding more symbols this late can cause layout issues.
   {
     eld::RegisterTimer T("Define Magic Symbols", "Establish Layout",
                          m_Module.getConfig().options().printTimingStats());