Index: lld/trunk/COFF/ICF.cpp
===================================================================
--- lld/trunk/COFF/ICF.cpp
+++ lld/trunk/COFF/ICF.cpp
@@ -73,12 +73,23 @@
 // 2017) says that /opt:icf folds both functions and read-only data.
 // Despite that, the MSVC linker folds only functions. We found
 // a few instances of programs that are not safe for data merging.
-// Therefore, we merge only functions just like the MSVC tool.
+// Therefore, we merge only functions just like the MSVC tool. However, we merge
+// identical .xdata sections, because the address of unwind information is
+// insignificant to the user program and the Visual C++ linker does this.
 bool ICF::isEligible(SectionChunk *C) {
+  // Non-comdat chunks, dead chunks, and writable chunks are not elegible.
+  bool Writable = C->getPermissions() & llvm::COFF::IMAGE_SCN_MEM_WRITE;
+  if (!C->isCOMDAT() || !C->isLive() || Writable)
+    return false;
+
+  // Code sections with external symbols are eligible.
   bool Global = C->Sym && C->Sym->isExternal();
   bool Executable = C->getPermissions() & llvm::COFF::IMAGE_SCN_MEM_EXECUTE;
-  bool Writable = C->getPermissions() & llvm::COFF::IMAGE_SCN_MEM_WRITE;
-  return C->isCOMDAT() && C->isLive() && Global && Executable && !Writable;
+  if (Global && Executable)
+    return true;
+
+  // .xdata unwind info sections are eligble.
+  return C->getSectionName().split('$').first == ".xdata";
 }
 
 // Split an equivalence class into smaller classes.
Index: lld/trunk/test/COFF/icf-xdata.s
===================================================================
--- lld/trunk/test/COFF/icf-xdata.s
+++ lld/trunk/test/COFF/icf-xdata.s
@@ -0,0 +1,86 @@
+# RUN: llvm-mc %s -triple x86_64-windows-msvc -filetype=obj -o %t.obj
+# RUN: lld-link %t.obj -dll -noentry -out:%t.dll
+# RUN: llvm-readobj -sections %t.dll | FileCheck %s
+
+# There shouldn't be much xdata, because all three .pdata entries (12 bytes
+# each) should use the same .xdata unwind info.
+# CHECK:         Name: .pdata
+# CHECK-NEXT:    VirtualSize: 0x24
+# CHECK:         Name: .xdata
+# CHECK-NEXT:    VirtualSize: 0x8
+
+	.text
+callee:
+	ret
+
+	.def	 xdata1;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,xdata1
+	.globl	xdata1                  # -- Begin function xdata1
+	.p2align	4, 0x90
+xdata1:                                 # @xdata1
+.seh_proc xdata1
+# BB#0:                                 # %entry
+	subq	$40, %rsp
+	.seh_stackalloc 40
+	.seh_endprologue
+	callq	callee
+	nop
+	addq	$40, %rsp
+	jmp	callee                  # TAILCALL
+	.seh_handlerdata
+	.section	.text,"xr",one_only,xdata1
+	.seh_endproc
+                                        # -- End function
+	.def	 xdata2;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,xdata2
+	.globl	xdata2                  # -- Begin function xdata2
+	.p2align	4, 0x90
+xdata2:                                 # @xdata2
+.seh_proc xdata2
+# BB#0:                                 # %entry
+	subq	$40, %rsp
+	.seh_stackalloc 40
+	.seh_endprologue
+	callq	callee
+	callq	callee
+	nop
+	addq	$40, %rsp
+	jmp	callee                  # TAILCALL
+	.seh_handlerdata
+	.section	.text,"xr",one_only,xdata2
+	.seh_endproc
+                                        # -- End function
+	.def	 xdata3;
+	.scl	2;
+	.type	32;
+	.endef
+	.section	.text,"xr",one_only,xdata3
+	.globl	xdata3                  # -- Begin function xdata3
+	.p2align	4, 0x90
+xdata3:                                 # @xdata3
+.seh_proc xdata3
+# BB#0:                                 # %entry
+	subq	$40, %rsp
+	.seh_stackalloc 40
+	.seh_endprologue
+	callq	callee
+	callq	callee
+	callq	callee
+	nop
+	addq	$40, %rsp
+	jmp	callee                  # TAILCALL
+	.seh_handlerdata
+	.section	.text,"xr",one_only,xdata3
+	.seh_endproc
+                                        # -- End function
+	.section	.drectve,"yn"
+	.ascii	" -export:xdata1"
+	.ascii	" -export:xdata2"
+	.ascii	" -export:xdata3"
+