diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
@@ -12,6 +12,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataExtractor.h"
@@ -29,6 +30,18 @@
 using namespace llvm;
 using namespace dwarf;
 
+static void printRegister(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH,
+                          unsigned RegNum) {
+  if (MRI) {
+    if (Optional<unsigned> LLVMRegNum = MRI->getLLVMRegNum(RegNum, IsEH)) {
+      if (const char *RegName = MRI->getName(*LLVMRegNum)) {
+        OS << RegName;
+        return;
+      }
+    }
+  }
+  OS << "reg" << RegNum;
+}
 
 // See DWARF standard v3, section 7.23
 const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
@@ -268,7 +281,8 @@
       OS << format(" %" PRId64 "*data_alignment_factor" , Operand);
     break;
   case OT_Register:
-    OS << format(" reg%" PRId64, Operand);
+    OS << ' ';
+    printRegister(OS, MRI, IsEH, Operand);
     break;
   case OT_Expression:
     assert(Instr.Expression && "missing DWARFExpression object");
diff --git a/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp b/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
--- a/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
+++ b/llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp
@@ -66,7 +66,8 @@
   uint32_t DWARFToGSYMFileIndex(GsymCreator &Gsym, uint32_t DwarfFileIdx) {
     if (!LineTable)
       return 0;
-    assert(DwarfFileIdx < FileCache.size());
+    if (DwarfFileIdx >= FileCache.size())
+      return 0;
     uint32_t &GsymFileIdx = FileCache[DwarfFileIdx];
     if (GsymFileIdx != UINT32_MAX)
       return GsymFileIdx;
diff --git a/llvm/test/DebugInfo/dwarfdump-debug-frame-simple.test b/llvm/test/DebugInfo/dwarfdump-debug-frame-simple.test
--- a/llvm/test/DebugInfo/dwarfdump-debug-frame-simple.test
+++ b/llvm/test/DebugInfo/dwarfdump-debug-frame-simple.test
@@ -5,8 +5,8 @@
 
 ; FRAMES: 00000000 00000010 ffffffff CIE
 ; FRAMES: Version: 1
-; FRAMES:      DW_CFA_def_cfa: reg4 +4
-; FRAMES-NEXT: DW_CFA_offset: reg8 -4
+; FRAMES:      DW_CFA_def_cfa: ESP +4
+; FRAMES-NEXT: DW_CFA_offset: EIP -4
 ; FRAMES-NEXT: DW_CFA_nop:
 ; FRAMES-NEXT: DW_CFA_nop:
 
@@ -18,9 +18,9 @@
 ; FRAMES: 00000028 00000014 00000000 FDE cie=00000000 pc=00000030...00000080
 ; FRAMES:      DW_CFA_advance_loc: 1
 ; FRAMES-NEXT: DW_CFA_def_cfa_offset: +8
-; FRAMES-NEXT: DW_CFA_offset: reg5 -8
+; FRAMES-NEXT: DW_CFA_offset: EBP -8
 ; FRAMES-NEXT: DW_CFA_advance_loc: 2
-; FRAMES-NEXT: DW_CFA_def_cfa_register: reg5
+; FRAMES-NEXT: DW_CFA_def_cfa_register: EBP
 
 ; FRAMES-NOT: CIE
 ; FRAMES-NOT: FDE
diff --git a/llvm/test/MC/ELF/cfi-restore-extended.s b/llvm/test/MC/ELF/cfi-restore-extended.s
--- a/llvm/test/MC/ELF/cfi-restore-extended.s
+++ b/llvm/test/MC/ELF/cfi-restore-extended.s
@@ -6,7 +6,7 @@
   nop
 // CHECK: DW_CFA_advance_loc: 1
   .cfi_restore %rbp
-// CHECK-NEXT: DW_CFA_restore: reg6
+// CHECK-NEXT: DW_CFA_restore: RBP
   nop
 // CHECK-NEXT: DW_CFA_advance_loc: 1
   .cfi_restore 89
@@ -14,4 +14,3 @@
 // CHECK-NEXT: DW_CFA_nop:
   nop
   .cfi_endproc
-
diff --git a/llvm/test/MC/X86/i386-darwin-frame-register.ll b/llvm/test/MC/X86/i386-darwin-frame-register.ll
--- a/llvm/test/MC/X86/i386-darwin-frame-register.ll
+++ b/llvm/test/MC/X86/i386-darwin-frame-register.ll
@@ -11,7 +11,7 @@
 ; CHECK: .debug_frame contents:
 ; CHECK: ffffffff CIE
 ; CHECK-NOT: {{CIE|FDE}}
-; CHECK:   DW_CFA_def_cfa: reg4 +4
+; CHECK:   DW_CFA_def_cfa: ESP +4
 
 ; ModuleID = 'foo.c'
 target datalayout = "e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128"