[Lldb-commits] [PATCH] D144528: [lldb] Warn when Mach-O files have overlapping segments

[Alex Langford via Phabricator via lldb-commits]

bulbazord created this revision.
bulbazord added reviewers: jasonmolenda, jingham, mib.
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I recently came across a binary that for some reason had overlapping
sections. When debugging it, LLDB was able to get information about one
of the sections but not the other because SectionLoadList assumes that
each address maps to exactly one section. We have the capability to warn
about this, but it was not turned on.

rdar://105751700


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D144528

Files:
  lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp


Index: lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
===================================================================
--- lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -6182,6 +6182,10 @@
   size_t num_loaded_sections = 0;
   const size_t num_sections = section_list->GetSize();
 
+  // Warn if some top-level segments map to the same address. The binary may be
+  // malformed.
+  const bool warn_multiple = true;
+
   if (value_is_offset) {
     // "value" is an offset to apply to each top level segment
     for (size_t sect_idx = 0; sect_idx < num_sections; ++sect_idx) {
@@ -6190,7 +6194,8 @@
       SectionSP section_sp(section_list->GetSectionAtIndex(sect_idx));
       if (SectionIsLoadable(section_sp.get()))
         if (target.GetSectionLoadList().SetSectionLoadAddress(
-                section_sp, section_sp->GetFileAddress() + value))
+                section_sp, section_sp->GetFileAddress() + value,
+                warn_multiple))
           ++num_loaded_sections;
     }
   } else {
@@ -6207,7 +6212,7 @@
                 value, mach_header_section, section_sp.get());
         if (section_load_addr != LLDB_INVALID_ADDRESS) {
           if (target.GetSectionLoadList().SetSectionLoadAddress(
-                  section_sp, section_load_addr))
+                  section_sp, section_load_addr, warn_multiple))
             ++num_loaded_sections;
         }
       }


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