Index: lld/Common/ErrorHandler.cpp
===================================================================
--- lld/Common/ErrorHandler.cpp
+++ lld/Common/ErrorHandler.cpp
@@ -120,21 +120,21 @@
   *ErrorOS << Msg << "\n";
 }
 
-void ErrorHandler::error(const Twine &Msg) {
+void ErrorHandler::error(const Twine &Msg, int NDiags) {
   std::lock_guard<std::mutex> Lock(Mu);
   newline(ErrorOS, Msg);
 
   if (ErrorLimit == 0 || ErrorCount < ErrorLimit) {
     print("error: ", raw_ostream::RED);
     *ErrorOS << Msg << "\n";
-  } else if (ErrorCount == ErrorLimit) {
+  } else if (ErrorCount >= ErrorLimit) {
     print("error: ", raw_ostream::RED);
     *ErrorOS << ErrorLimitExceededMsg << "\n";
     if (ExitEarly)
       exitLld(1);
   }
 
-  ++ErrorCount;
+  ErrorCount += NDiags;
 }
 
 void ErrorHandler::fatal(const Twine &Msg) {
Index: lld/ELF/Relocations.cpp
===================================================================
--- lld/ELF/Relocations.cpp
+++ lld/ELF/Relocations.cpp
@@ -710,8 +710,11 @@
 // can happen before lld emits diagnostics.
 struct UndefinedDiag {
   Symbol *Sym;
-  InputSectionBase *Sec;
-  uint64_t Offset;
+  struct Loc {
+    InputSectionBase *Sec;
+    uint64_t Offset;
+  };
+  std::vector<Loc> Locs;
   bool IsWarning;
 };
 static std::vector<UndefinedDiag>& Undefs() {
@@ -723,8 +726,6 @@
 template <class ELFT>
 static void reportUndefinedSymbol(const UndefinedDiag &Undef) {
   Symbol &Sym = *Undef.Sym;
-  InputSectionBase &Sec = *Undef.Sec;
-  uint64_t Offset = Undef.Offset;
 
   auto Visibility = [&]() -> std::string {
     switch (Sym.Visibility) {
@@ -743,11 +744,19 @@
   if (Msg.empty())
     Msg = "undefined " + Visibility() + "symbol: " + toString(Sym);
 
-  Msg += "\n>>> referenced by ";
-  std::string Src = Sec.getSrcMsg(Sym, Offset);
-  if (!Src.empty())
-    Msg += Src + "\n>>>               ";
-  Msg += Sec.getObjMsg(Offset);
+  size_t i = 0;
+  for (; i < Undef.Locs.size() && errorCount() + i < errorHandler().ErrorLimit;
+       ++i) {
+    UndefinedDiag::Loc L = Undef.Locs[i];
+    InputSectionBase &Sec = *L.Sec;
+    uint64_t Offset = L.Offset;
+
+    Msg += "\n>>> referenced by ";
+    std::string Src = Sec.getSrcMsg(Sym, Offset);
+    if (!Src.empty())
+      Msg += Src + "\n>>>               ";
+    Msg += Sec.getObjMsg(Offset);
+  }
 
   if (Sym.getName().startswith("_ZTV"))
     Msg += "\nthe vtable symbol may be undefined because the class is missing "
@@ -756,13 +765,29 @@
   if (Undef.IsWarning)
     warn(Msg);
   else
-    error(Msg);
+    error(Msg, /*NDiags=*/i);
 }
 
 template <class ELFT>
 void elf::reportUndefinedSymbols() {
-  for (const auto& Undef: Undefs())
-    reportUndefinedSymbol<ELFT>(Undef);
+  // Find the first "undefined symbol" diagnostic for each diagnostic, and
+  // collect all "referenced from" lines at the first diagnostic.
+  std::map<Symbol*, size_t> FirstRef;
+  for (size_t i = 0; i < Undefs().size(); ++i) {
+    auto& Undef = Undefs()[i];
+    auto it = FirstRef.find(Undef.Sym);
+    if (it == FirstRef.end()) {
+      FirstRef[Undef.Sym] = i;
+    } else {
+      Undefs()[it->second].Locs.push_back(Undef.Locs[0]);
+      Undef.Locs.clear();
+    }
+  }
+
+  for (const auto& Undef : Undefs()) {
+    if (!Undef.Locs.empty())
+      reportUndefinedSymbol<ELFT>(Undef);
+  }
 }
 
 // Report an undefined symbol if necessary.
@@ -788,7 +813,7 @@
     return false;
 
 
-  UndefinedDiag Undef = { &Sym, &Sec, Offset, /*IsWarning=*/false };
+  UndefinedDiag Undef = { &Sym, {{&Sec, Offset}}, /*IsWarning=*/false };
   if ((Config->UnresolvedSymbols == UnresolvedPolicy::Warn && CanBeExternal) ||
       Config->NoinhibitExec)
     Undef.IsWarning = true;
Index: lld/include/lld/Common/ErrorHandler.h
===================================================================
--- lld/include/lld/Common/ErrorHandler.h
+++ lld/include/lld/Common/ErrorHandler.h
@@ -92,7 +92,7 @@
   bool FatalWarnings = false;
   bool Verbose = false;
 
-  void error(const Twine &Msg);
+  void error(const Twine &Msg, int NDiags = 1);
   LLVM_ATTRIBUTE_NORETURN void fatal(const Twine &Msg);
   void log(const Twine &Msg);
   void message(const Twine &Msg);
@@ -107,7 +107,9 @@
 /// Returns the default error handler.
 ErrorHandler &errorHandler();
 
-inline void error(const Twine &Msg) { errorHandler().error(Msg); }
+inline void error(const Twine &Msg, int NDiags = 1) {
+  errorHandler().error(Msg, NDiags);
+}
 inline LLVM_ATTRIBUTE_NORETURN void fatal(const Twine &Msg) {
   errorHandler().fatal(Msg);
 }
Index: lld/test/ELF/debug-line-obj.s
===================================================================
--- lld/test/ELF/debug-line-obj.s
+++ lld/test/ELF/debug-line-obj.s
@@ -10,7 +10,6 @@
 # CHECK:      error: undefined symbol: foo()
 # CHECK-NEXT: >>> referenced by test.cpp:2
 # CHECK-NEXT: >>>               {{.*}}.o:(bar())
-# CHECK:      error: undefined symbol: foo()
 # CHECK-NEXT: >>> referenced by test.cpp:3
 # CHECK-NEXT: >>>               {{.*}}.o:(baz())
 
Index: lld/test/ELF/undef-multi.s
===================================================================
--- /dev/null
+++ lld/test/ELF/undef-multi.s
@@ -0,0 +1,47 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/undef.s -o %t2.o
+# RUN: not ld.lld %t.o %t2.o -o %t.exe 2>&1 | FileCheck %s
+
+# CHECK: error: undefined symbol: zed2
+# CHECK-NEXT: >>> referenced by undef-multi.s
+# CHECK-NEXT: >>>               {{.*}}:(.text+0x1)
+# CHECK-NEXT: >>> referenced by undef-multi.s
+# CHECK-NEXT: >>>               {{.*}}:(.text+0x6)
+# CHECK-NEXT: >>> referenced by undef-multi.s
+# CHECK-NEXT: >>>               {{.*}}:(.text+0xB)
+# CHECK-NEXT: >>> referenced by undef-multi.s
+# CHECK-NEXT: >>>               {{.*}}:(.text+0x10)
+# CHECK-NEXT: >>> referenced by {{.*}}tmp2.o:(.text+0x0)
+
+# RUN: not ld.lld %t.o %t2.o -o %t.exe -error-limit=3 2>&1 | \
+# RUN:     FileCheck --check-prefix=LIMIT %s
+
+# LIMIT: error: undefined symbol: zed2
+# LIMIT-NEXT: >>> referenced by undef-multi.s
+# LIMIT-NEXT: >>>               {{.*}}:(.text+0x1)
+# LIMIT-NEXT: >>> referenced by undef-multi.s
+# LIMIT-NEXT: >>>               {{.*}}:(.text+0x6)
+# LIMIT-NEXT: >>> referenced by undef-multi.s
+# LIMIT-NEXT: >>>               {{.*}}:(.text+0xB)
+# LIMIT-NOT: >>> referenced by undef-multi.s
+# LIMIT-NOT: >>>               {{.*}}:(.text+0x10)
+# LIMIT-NOT: >>> referenced by {{.*}}tmp2.o:(.text+0x0)
+
+.file "undef-multi.s"
+
+  .globl _start
+_start:
+  call zed2
+
+  .globl _f
+_f:
+  call zed2
+
+  .globl _g
+_g:
+  call zed2
+
+  .globl _h
+_h:
+  call zed2