[Lldb-commits] [lldb] Read and store gnu build id from loaded core file (PR #92492)

[Pavel Labath via lldb-commits]

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@@ -983,6 +994,67 @@ llvm::Error ProcessElfCore::ParseThreadContextsFromNoteSegment(
   }
 }
 
+UUID ProcessElfCore::FindBuidIdInCoreMemory(lldb::addr_t address) {
+  UUID invalid_uuid;
+  const uint32_t addr_size = GetAddressByteSize();
+  const size_t elf_header_size = addr_size == 4 ? sizeof(llvm::ELF::Elf32_Ehdr)
+                                                : sizeof(llvm::ELF::Elf64_Ehdr);
+
+  // 80 bytes buffer is larger enough for the ELF header or program headers
+  unsigned char buf[80];
+  Status error;
+  size_t byte_read = ReadMemory(address, buf, elf_header_size, error);
+  if (byte_read != elf_header_size || !elf::ELFHeader::MagicBytesMatch(buf))
+    return invalid_uuid;
+  assert(sizeof(buf) >= elf_header_size);
+  DataExtractor elf_header_data(buf, elf_header_size, GetByteOrder(),
+                                addr_size);
+  lldb::offset_t offset = 0;
+
+  elf::ELFHeader elf_header;
+  elf_header.Parse(elf_header_data, &offset);
+
+  const lldb::addr_t ph_addr = address + elf_header.e_phoff;
+
+  for (unsigned int i = 0; i < elf_header.e_phnum; ++i) {
+    byte_read = ReadMemory(ph_addr + i * elf_header.e_phentsize, buf,
+                           elf_header.e_phentsize, error);
+    if (byte_read != elf_header.e_phentsize)
+      break;
+    assert(sizeof(buf) >= elf_header.e_phentsize);
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labath wrote:

This could be a static_assert, but it might even be better to do declare the array as something like `char buf[sizeof(Elf64_Ehdr)] and avoid any doubt about it being large enough (then you also wouldn't need the comment above the array declaration).

https://github.com/llvm/llvm-project/pull/92492