Merge pull request swiftlang#9672 from jasonmolenda/cp/r140432279-handle-large-vm-offset-shared-cache-segments

[lldb][Mach-O] Handle shared cache binaries correctly (llvm#117832)

Author: jasonmolenda

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

@@ -2244,11 +2244,11 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
   LLDB_LOG(log, "Parsing symbol table for {0}", file_name);
   Progress progress("Parsing symbol table", file_name);
 
-  llvm::MachO::symtab_command symtab_load_command = {0, 0, 0, 0, 0, 0};
   llvm::MachO::linkedit_data_command function_starts_load_command = {0, 0, 0, 0};
   llvm::MachO::linkedit_data_command exports_trie_load_command = {0, 0, 0, 0};
   llvm::MachO::dyld_info_command dyld_info = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
   llvm::MachO::dysymtab_command dysymtab = m_dysymtab;
+  SymtabCommandLargeOffsets symtab_load_command;
   // The data element of type bool indicates that this entry is thumb
   // code.
   typedef AddressDataArray<lldb::addr_t, bool, 100> FunctionStarts;
@@ -2285,12 +2285,20 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
     // Watch for the symbol table load command
     switch (lc.cmd) {
     case LC_SYMTAB:
+      // struct symtab_command {
+      //   uint32_t        cmd;            /* LC_SYMTAB */
+      //   uint32_t        cmdsize;        /* sizeof(struct symtab_command) */
+      //   uint32_t        symoff;         /* symbol table offset */
+      //   uint32_t        nsyms;          /* number of symbol table entries */
+      //   uint32_t        stroff;         /* string table offset */
+      //   uint32_t        strsize;        /* string table size in bytes */
+      // };
       symtab_load_command.cmd = lc.cmd;
       symtab_load_command.cmdsize = lc.cmdsize;
-      // Read in the rest of the symtab load command
-      if (m_data.GetU32(&offset, &symtab_load_command.symoff, 4) ==
-          nullptr) // fill in symoff, nsyms, stroff, strsize fields
-        return;
+      symtab_load_command.symoff = m_data.GetU32(&offset);
+      symtab_load_command.nsyms = m_data.GetU32(&offset);
+      symtab_load_command.stroff = m_data.GetU32(&offset);
+      symtab_load_command.strsize = m_data.GetU32(&offset);
       break;
 
     case LC_DYLD_INFO:

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.h

@@ -256,6 +256,19 @@ class ObjectFileMachO : public lldb_private::ObjectFile {
     bool IsValid() { return all_image_infos.size() > 0; }
   };
 
+  // The LC_SYMTAB's symtab_command structure uses 32-bit file offsets
+  // for two fields, but ObjectFileMachO needs to calculate the offsets
+  // in virtual address layout from the start of the TEXT segment, and
+  // that span may be larger than 4GB.
+  struct SymtabCommandLargeOffsets {
+    uint32_t cmd = 0;          /* LC_SYMTAB */
+    uint32_t cmdsize = 0;      /* sizeof(struct symtab_command) */
+    lldb::offset_t symoff = 0; /* symbol table offset */
+    uint32_t nsyms = 0;        /* number of symbol table entries */
+    lldb::offset_t stroff = 0; /* string table offset */
+    uint32_t strsize = 0;      /* string table size in bytes */
+  };
+
   /// Get the list of binary images that were present in the process
   /// when the corefile was produced.
   /// \return