[ELF] Print file:line for unknown PHDR error

Differential revision: https://reviews.llvm.org/D27335

llvm-svn: 288678
diff --git a/lld/ELF/LinkerScript.h b/lld/ELF/LinkerScript.h
index f2d49a8..3bcfc57 100644
--- a/lld/ELF/LinkerScript.h
+++ b/lld/ELF/LinkerScript.h
@@ -124,6 +124,7 @@
   std::vector<StringRef> Phdrs;
   uint32_t Filler = 0;
   ConstraintKind Constraint = ConstraintKind::NoConstraint;
+  std::string Location;
 };
 
 // This struct represents one section match pattern in SECTIONS() command.
@@ -268,7 +269,7 @@
   ScriptConfiguration &Opt = *ScriptConfig;
 
   std::vector<size_t> getPhdrIndices(StringRef SectionName);
-  size_t getPhdrIndex(StringRef PhdrName);
+  size_t getPhdrIndex(const Twine &Loc, StringRef PhdrName);
 
   uintX_t Dot;
   uintX_t LMAOffset = 0;