Index: lldb/lit/SymbolFile/Inputs/sizeless-symbol.s
===================================================================
--- /dev/null
+++ lldb/lit/SymbolFile/Inputs/sizeless-symbol.s
@@ -0,0 +1,12 @@
+        .text
+        .byte   0
+sizeless:
+        .globl  sizeless 
+        .type   sizeless, @object
+sizeful:
+        .globl  sizeful
+        .type   sizeful, @object
+        .byte   0
+        .byte   0
+sizeend:
+        .size   sizeful, sizeend - sizeful
Index: lldb/lit/SymbolFile/sizeless-symbol.test
===================================================================
--- /dev/null
+++ lldb/lit/SymbolFile/sizeless-symbol.test
@@ -0,0 +1,7 @@
+# RUN: %clang %S/Inputs/sizeless-symbol.s -c -o %t.o
+# RUN: %lldb %t.o -s %s -o quit | FileCheck %s
+
+image lookup --address 1
+# CHECK: Summary: sizeless-symbol.test.tmp.o`sizeful
+image lookup --address 2
+# CHECK: Summary: sizeless-symbol.test.tmp.o`sizeful + 1
Index: lldb/source/Symbol/Symtab.cpp
===================================================================
--- lldb/source/Symbol/Symtab.cpp
+++ lldb/source/Symbol/Symtab.cpp
@@ -873,7 +873,7 @@
         m_file_addr_to_index.Append(entry);
       }
     }
-    const size_t num_entries = m_file_addr_to_index.GetSize();
+    const ssize_t num_entries = m_file_addr_to_index.GetSize();
     if (num_entries > 0) {
       m_file_addr_to_index.Sort();
 
@@ -893,11 +893,15 @@
       // entries that didn't already have a size from the Symbol (e.g. if we
       // have a plain linker symbol with an address only, instead of debug info
       // where we get an address and a size and a type, etc.)
-      for (size_t i = 0; i < num_entries; i++) {
+      // Check symbols downwards as symbols at the same address with size will
+      // be ordered after zero-sized symbols.
+      for (ssize_t i = num_entries - 1 ; i >= 0; --i) {
         FileRangeToIndexMap::Entry *entry =
             m_file_addr_to_index.GetMutableEntryAtIndex(i);
-        if (entry->GetByteSize() == 0) {
-          addr_t curr_base_addr = entry->GetRangeBase();
+        if (entry->GetByteSize() > 0)
+          continue;
+        addr_t curr_base_addr = entry->GetRangeBase();
+        if (i == num_entries - 1 || m_file_addr_to_index.GetMutableEntryAtIndex(i + 1)->GetRangeBase() != curr_base_addr) {
           const RangeVector<addr_t, addr_t>::Entry *containing_section =
               section_ranges.FindEntryThatContains(curr_base_addr);
 
@@ -909,7 +913,7 @@
                 (entry->GetRangeBase() - containing_section->GetRangeBase());
           }
 
-          for (size_t j = i; j < num_entries; j++) {
+          for (ssize_t j = i; j < num_entries; j++) {
             FileRangeToIndexMap::Entry *next_entry =
                 m_file_addr_to_index.GetMutableEntryAtIndex(j);
             addr_t next_base_addr = next_entry->GetRangeBase();