[Lldb-commits] [lldb] cee05ee - [lldb] Warn when Mach-O files have overlapping segments

[Alex Langford via lldb-commits]

Author: Alex Langford
Date: 2023-02-22T13:22:15-08:00
New Revision: cee05eed2f478630b5435070bdefe06156dc5035

URL: https://github.com/llvm/llvm-project/commit/cee05eed2f478630b5435070bdefe06156dc5035
DIFF: https://github.com/llvm/llvm-project/commit/cee05eed2f478630b5435070bdefe06156dc5035.diff

LOG: [lldb] Warn when Mach-O files have overlapping segments

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

Differential Revision: https://reviews.llvm.org/D144528

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
index 84856590fe8ad..eaa47359ac882 100644
--- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -6182,6 +6182,10 @@ bool ObjectFileMachO::SetLoadAddress(Target &target, lldb::addr_t value,
   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 @@ bool ObjectFileMachO::SetLoadAddress(Target &target, lldb::addr_t value,
       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 @@ bool ObjectFileMachO::SetLoadAddress(Target &target, lldb::addr_t value,
                 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;
         }
       }