Index: llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
===================================================================
--- /dev/null
+++ llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
@@ -0,0 +1,45 @@
+$ cat dwarf5-addrx-0x0-last.c
+#include <stdio.h>
+
+int main (int argc, char const *argv[])
+{
+  int pass_me = argc + 10;
+  printf("Foo\n");
+  printf("Bar\n");
+
+  return 0;
+}
+
+$ clang -gdwarf-5 dwarf5-addrx-0x0-last.c -c -o dwarf5-addrx-0x0-last.o
+$ clang dwarf5-addrx-0x0-last.o -o dwarf5-addrx-0x0-last.out
+
+# Sanity check: make sure main's low PC (0x0) requires an index computation
+# into the .debug_addr section.
+RUN: llvm-dwarfdump -debug-addr %p/../Inputs/private/tmp/dwarf5/dwarf5-addrx-0x0-last.o | FileCheck %s --check-prefix DEBUGADDR
+
+DEBUGADDR: Addrs: [
+DEBUGADDR: 0x0000000000000054
+DEBUGADDR: 0x0000000000000059
+DEBUGADDR: 0x0000000000000000
+DEBUGADDR: ]
+
+RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/dwarf5/dwarf5-addrx-0x0-last.out -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
+RUN: llvm-dwarfdump --verbose -debug-info %t.dSYM | FileCheck %s --check-prefix DEBUGINFO
+RUN: llvm-dwarfdump --verbose -debug-line %t.dSYM | FileCheck %s --check-prefix DEBUGLINE
+
+CHECK-NOT: error:
+
+DEBUGINFO:   DW_TAG_subprogram
+DEBUGINFO:     DW_AT_low_pc [DW_FORM_addr]     (0x0000000100003f4c)
+DEBUGINFO:     DW_AT_high_pc [DW_FORM_data4]   (0x00000054)
+DEBUGINFO:     DW_AT_name [DW_FORM_strp]       ( .debug_str[0x0000011c] = "main")
+
+DEBUGLINE:  0x0000000100003f4c   4   0  {{.*}}  is_stmt
+DEBUGLINE:  0x0000000100003f6c   5  17  {{.*}}  is_stmt prologue_end
+DEBUGLINE:  0x0000000100003f70   5  22  {{.*}}
+DEBUGLINE:  0x0000000100003f74   5   7  {{.*}}
+DEBUGLINE:  0x0000000100003f78   6   3  {{.*}}  is_stmt
+DEBUGLINE:  0x0000000100003f84   7   3  {{.*}}  is_stmt
+DEBUGLINE:  0x0000000100003f94   9   3  {{.*}}  is_stmt epilogue_begin
+DEBUGLINE:  0x0000000100003fa0   9   3  {{.*}}  is_stmt end_sequence
Index: llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
===================================================================
--- llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
+++ llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
@@ -1081,10 +1081,16 @@
     std::optional<DWARFFormValue> AddrValue = DIE.find(dwarf::DW_AT_low_pc);
     if (std::optional<uint64_t> AddrOffsetSectionBase =
             DIE.getDwarfUnit()->getAddrOffsetSectionBase()) {
-      uint64_t StartOffset = *AddrOffsetSectionBase + AddrValue->getRawUValue();
-      uint64_t EndOffset =
-          StartOffset + DIE.getDwarfUnit()->getAddressByteSize();
-      return hasValidRelocationAt(ValidDebugAddrRelocs, StartOffset, EndOffset);
+      // Addrx is a index into the debug_addr section, not an offset, so we need
+      // to multiply by byte size.
+      const uint64_t ByteSize = DIE.getDwarfUnit()->getAddressByteSize();
+      const uint64_t StartOffset =
+          *AddrOffsetSectionBase + (AddrValue->getRawUValue() * ByteSize);
+      const uint64_t EndOffset = StartOffset + ByteSize;
+      if (std::optional<int64_t> RelocAdjustment = hasValidRelocationAt(
+              ValidDebugAddrRelocs, StartOffset, EndOffset))
+        return RelocAdjustment;
+      return std::nullopt;
     }
 
     Linker.reportWarning("no base offset for address table", SrcFileName);