[Lldb-commits] [PATCH] D140066: Add a final fallback technique to the old Darwin dynamic loader plugin to find the dyld_all_image_infos structure

[Jason Molenda via Phabricator via lldb-commits]

jasonmolenda created this revision.
jasonmolenda added a reviewer: JDevlieghere.
jasonmolenda added a project: LLDB.
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When lldb is running on a userland corefile (the only case where 
DynamicLoaderMacOSX is still used today), lldb finds dyld in the corefile by 
exhaustive search, then reads the symbol table in the corefile to find the 
"dyld_all_image_infos" symbol.  Using this object in the corefile, we can find 
the filepaths & load addresses of all other binaries.

This patch adds an additional fallback if we can't find the symbol name 
"dyld_all_image_infos" - by looking for the named section in dyld that is used 
specifically to identify this object.  It is only used after the two function 
names we try have failed, at the point where we have no other possible ways to 
find the dyld_all_image_infos object in the corefile.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D140066

Files:
  lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp


Index: lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
@@ -277,6 +277,16 @@
           m_dyld_all_image_infos_addr = symbol->GetLoadAddress(&target);
       }
 
+      if (m_dyld_all_image_infos_addr == LLDB_INVALID_ADDRESS) {
+        ConstString g_sect_name("__all_image_info");
+        SectionSP dyld_aii_section_sp =
+            dyld_module_sp->GetSectionList()->FindSectionByName(g_sect_name);
+        if (dyld_aii_section_sp) {
+          Address dyld_aii_addr(dyld_aii_section_sp, 0);
+          m_dyld_all_image_infos_addr = dyld_aii_addr.GetLoadAddress(&target);
+        }
+      }
+
       // Update all image infos
       InitializeFromAllImageInfos();
 



Index: lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
@@ -277,6 +277,16 @@
           m_dyld_all_image_infos_addr = symbol->GetLoadAddress(&target);
       }
 
+      if (m_dyld_all_image_infos_addr == LLDB_INVALID_ADDRESS) {
+        ConstString g_sect_name("__all_image_info");
+        SectionSP dyld_aii_section_sp =
+            dyld_module_sp->GetSectionList()->FindSectionByName(g_sect_name);
+        if (dyld_aii_section_sp) {
+          Address dyld_aii_addr(dyld_aii_section_sp, 0);
+          m_dyld_all_image_infos_addr = dyld_aii_addr.GetLoadAddress(&target);
+        }
+      }
+
       // Update all image infos
       InitializeFromAllImageInfos();
 

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