[ELF] - Remove excessive loop in LinkerScript<ELFT>::assignAddresses()

[grimar]

Summary

After 278461 "Create only one section for a name in LinkerScript."

this loop is excessive. Patch also reorders code slightly to use early return.

[ruiu]

LGTM

lld/trunk/ELF/LinkerScript.cpp

if (auto *Cmd = dyn_cast<SymbolAssignment>(Base.get())) {
       continue;
     }
 
     if (auto *Cmd = dyn_cast<AssertCommand>(Base.get())) {
       Cmd->Expression(Dot);
       continue;
     }
 
-    // Find all the sections with required name. There can be more than
-    // one section with such name, if the alignment, flags or type
-    // attribute differs.
     auto *Cmd = cast<OutputSectionCommand>(Base.get());
-    for (OutputSectionBase<ELFT> *Sec : *OutputSections) {
-      if (Sec->getName() != Cmd->Name)
-        continue;
+    auto I = llvm::find_if(*OutputSections, [&](OutputSectionBase<ELFT> *S) {
+      return S->getName() == Cmd->Name;
+    });
+    if (I == OutputSections->end())
+    OutputSectionBase<ELFT> *Sec = *I;
 
-      if (Cmd->AddrExpr)
-        Dot = Cmd->AddrExpr(Dot);
 
-      if (Cmd->AlignExpr)
-        Sec->updateAlignment(Cmd->AlignExpr(Dot));
 
-      if ((Sec->getFlags() & SHF_TLS) && Sec->getType() == SHT_NOBITS) {
-        uintX_t TVA = Dot + ThreadBssOffset;
-        TVA = alignTo(TVA, Sec->getAlignment());
-        Sec->setVA(TVA);
-        assignOffsets(Sec);
-        ThreadBssOffset = TVA - Dot + Sec->getSize();
-        continue;
-      }
 
-      if (Sec->getFlags() & SHF_ALLOC) {
-        Dot = alignTo(Dot, Sec->getAlignment());
-        Sec->setVA(Dot);
-        assignOffsets(Sec);
-        MinVA = std::min(MinVA, Dot);
-        Dot += Sec->getSize();
-        continue;
-      }
-      Sec->assignOffsets();
-    }
+    if (!(Sec->getFlags() & SHF_ALLOC)) {
+      Sec->assignOffsets();
+      continue;
+    }
+
   }
 
   // ELF and Program headers need to be right before the first section in
   // memory. Set their addresses accordingly.
   MinVA = alignDown(MinVA - Out<ELFT>::ElfHeader->getSize() -
                         Out<ELFT>::ProgramHeaders->getSize(),
                     Target->PageSize);
   Out<ELFT>::ElfHeader->setVA(MinVA);