[lldb] Implement ObjectFile::GetCStrFromSection

[aprantl]

lldb/include/lldb/Symbol/ObjectFile.h

676

Can you add a doxygen comment for the method?

677

Should we call it GetCStringFromSection, or even better ReadCStringFromSection?

lldb/source/Symbol/ObjectFile.cpp

558

The fact that it's a C string seems to be not relevant to the function. It seems to just convert a file address to a load address?

[augusto2112]

lldb/include/lldb/Symbol/ObjectFile.h

677

I agree that ReadCStringFromSection sounds better.

lldb/source/Symbol/ObjectFile.cpp

558

What do you mean? This function calls m_data.GetCStr and returns the result.

[labath]

I don't think this implementation is sound. If you look at the implementation of ReadSectionData you'll see that there is a lot more involved in reading data from a section than just incrementing a pointer.

[andcarminati]

lldb/source/Symbol/ObjectFile.cpp

559

Wouldn't it be better to use

section->GetFileOffset()

to access m_data? As this object contains data loaded from the file.

lldb/include/lldb/Symbol/ObjectFile.h

virtual size_t ReadSectionData(Section *section,
                                  size_t dst_len);
 
   // This function will transparently decompress section data if the section if
   // compressed. Note that for compressed section the resulting data size may
   // be larger than what Section::GetFileSize reports.
   virtual size_t ReadSectionData(Section *section,
                                  DataExtractor &section_data);
 
+  const char *GetCStrFromSection(Section *section,
+                                 lldb::offset_t section_offset) const;
+
   bool IsInMemory() const { return m_memory_addr != LLDB_INVALID_ADDRESS; }
 
   // Strip linker annotations (such as @@VERSION) from symbol names.
   virtual llvm::StringRef
   StripLinkerSymbolAnnotations(llvm::StringRef symbol_name) const {
     return symbol_name;
   }
 

lldb/source/Symbol/ObjectFile.cpp

size_t ObjectFile::ReadSectionData(Section *section,
   }
 
   // The object file now contains a full mmap'ed copy of the object file
   // data, so just use this
   return GetData(section->GetFileOffset(), section->GetFileSize(),
                   section_data);
 }
 
+const char *
+ObjectFile::GetCStrFromSection(Section *section,
+                               lldb::offset_t section_offset) const {
+  offset_t offset = section->GetOffset() + section_offset;
+  return m_data.GetCStr(&offset);
+}
+
 bool ObjectFile::SplitArchivePathWithObject(llvm::StringRef path_with_object,
                                             FileSpec &archive_file,
                                             ConstString &archive_object,
                                             bool must_exist) {
   size_t len = path_with_object.size();
   if (len < 2 || path_with_object.back() != ')')
     return false;
   llvm::StringRef archive = path_with_object.substr(0, path_with_object.rfind('('));