[JITLink][i386] Get rid of EdgeKind_i386::None.

R_386_NONE ELF edges should be handled by skipping the relocation, rather than
adding no-op edges to the LinkGraph.

Author: lhames

llvm/include/llvm/ExecutionEngine/JITLink/i386.h

@@ -20,9 +20,6 @@ namespace llvm::jitlink::i386 {
 /// Represets i386 fixups
 enum EdgeKind_i386 : Edge::Kind {
 
-  /// None
-  None = Edge::FirstRelocation,
-
   /// A plain 32-bit pointer value relocation.
   ///
   /// Fixup expression:
@@ -32,7 +29,7 @@ enum EdgeKind_i386 : Edge::Kind {
   ///   - The target must reside in the low 32-bits of the address space,
   ///     otherwise an out-of-range error will be returned.
   ///
-  Pointer32,
+  Pointer32 = Edge::FirstRelocation,
 
   /// A 32-bit PC-relative relocation.
   ///
@@ -192,10 +189,6 @@ inline Error applyFixup(LinkGraph &G, Block &B, const Edge &E,
   auto FixupAddress = B.getAddress() + E.getOffset();
 
   switch (E.getKind()) {
-  case i386::None: {
-    break;
-  }
-
   case i386::Pointer32: {
     uint32_t Value = E.getTarget().getAddress().getValue() + E.getAddend();
     *(ulittle32_t *)FixupPtr = Value;

llvm/lib/ExecutionEngine/JITLink/ELF_i386.cpp

@@ -117,8 +117,6 @@ class ELFLinkGraphBuilder_i386 : public ELFLinkGraphBuilder<object::ELF32LE> {
   Expected<i386::EdgeKind_i386> getRelocationKind(const uint32_t Type) {
     using namespace i386;
     switch (Type) {
-    case ELF::R_386_NONE:
-      return EdgeKind_i386::None;
     case ELF::R_386_32:
       return EdgeKind_i386::Pointer32;
     case ELF::R_386_PC32:
@@ -170,6 +168,12 @@ class ELFLinkGraphBuilder_i386 : public ELFLinkGraphBuilder<object::ELF32LE> {
                             Block &BlockToFix) {
     using Base = ELFLinkGraphBuilder<ELFT>;
 
+    auto ELFReloc = Rel.getType(false);
+
+    // R_386_NONE is a no-op.
+    if (LLVM_UNLIKELY(ELFReloc == ELF::R_386_NONE))
+      return Error::success();
+
     uint32_t SymbolIndex = Rel.getSymbol(false);
     auto ObjSymbol = Base::Obj.getRelocationSymbol(Rel, Base::SymTabSec);
     if (!ObjSymbol)
@@ -184,16 +188,14 @@ class ELFLinkGraphBuilder_i386 : public ELFLinkGraphBuilder<object::ELF32LE> {
                   Base::GraphSymbols.size()),
           inconvertibleErrorCode());
 
-    Expected<i386::EdgeKind_i386> Kind = getRelocationKind(Rel.getType(false));
+    Expected<i386::EdgeKind_i386> Kind = getRelocationKind(ELFReloc);
     if (!Kind)
       return Kind.takeError();
 
     auto FixupAddress = orc::ExecutorAddr(FixupSection.sh_addr) + Rel.r_offset;
     int64_t Addend = 0;
 
     switch (*Kind) {
-    case i386::EdgeKind_i386::None:
-      break;
     case i386::EdgeKind_i386::Pointer32:
     case i386::EdgeKind_i386::PCRel32:
     case i386::EdgeKind_i386::RequestGOTAndTransformToDelta32FromGOT:

llvm/lib/ExecutionEngine/JITLink/i386.cpp

@@ -18,8 +18,6 @@ namespace llvm::jitlink::i386 {
 
 const char *getEdgeKindName(Edge::Kind K) {
   switch (K) {
-  case None:
-    return "None";
   case Pointer32:
     return "Pointer32";
   case PCRel32: