PECOFF: Implement GetBaseAddress

[labath]

Summary

COFF files are modelled in lldb as having one big container section
spanning the entire module image, with the actual sections being
subsections of that. In this model, the base address is simply the
address of the first byte of that section.

This also removes the hack where ObjectFilePECOFF was using the
m_file_offset field to communicate this information. Using file offset
for this purpose is completely wrong, as that is supposed to indicate
where is this ObjectFile located in the file on disk. This field is only
meaningful for fat binaries, and should normally be 0.

Both PDB plugins have been updated to use GetBaseAddress instead of
GetFileOffset.

[labath]

ping

[stella.stamenova]

LGTM. Now might not be the best time to commit it though because the LLDB build is broken on Windows.

[labath]

Thank you. It looks like windows is green now, so I'll go ahead and commit this.

[labath]

Committed in r354258.

lit/Modules/PECOFF/basic-info.yaml

+# RUN: yaml2obj %s > %t
+# RUN: lldb-test object-file %t | FileCheck %s
+
+# CHECK: Plugin name: pe-coff
+# CHECK: Architecture: x86_64-pc-windows-msvc
+# CHECK: UUID: 
+# CHECK: Executable: true
+# CHECK: Stripped: false
+# CHECK: Type: executable
+# CHECK: Strata: user
+# CHECK: Base VM address: 0x47000
+
+--- !COFF
+OptionalHeader:  
+  AddressOfEntryPoint: 4096
+  ImageBase:       290816
+  SectionAlignment: 4096
+  FileAlignment:   512
+  MajorOperatingSystemVersion: 6
+  MinorOperatingSystemVersion: 0
+  MajorImageVersion: 0
+  MinorImageVersion: 0
+  MajorSubsystemVersion: 6
+  MinorSubsystemVersion: 0
+  Subsystem:       IMAGE_SUBSYSTEM_WINDOWS_CUI
+  DLLCharacteristics: [ IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA, IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE, IMAGE_DLL_CHARACTERISTICS_NX_COMPAT, IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE ]
+  SizeOfStackReserve: 1048576
+  SizeOfStackCommit: 4096
+  SizeOfHeapReserve: 1048576
+  SizeOfHeapCommit: 4096
+  ExportTable:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  ImportTable:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  ResourceTable:   
+    RelativeVirtualAddress: 0
+    Size:            0
+  ExceptionTable:  
+    RelativeVirtualAddress: 0
+    Size:            0
+  CertificateTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  BaseRelocationTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  Debug:           
+    RelativeVirtualAddress: 0
+    Size:            0
+  Architecture:    
+    RelativeVirtualAddress: 0
+    Size:            0
+  GlobalPtr:       
+    RelativeVirtualAddress: 0
+    Size:            0
+  TlsTable:        
+    RelativeVirtualAddress: 0
+    Size:            0
+  LoadConfigTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  BoundImport:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  IAT:             
+    RelativeVirtualAddress: 0
+    Size:            0
+  DelayImportDescriptor: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  ClrRuntimeHeader: 
+    RelativeVirtualAddress: 0
+    Size:            0
+header:          
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: [ IMAGE_FILE_EXECUTABLE_IMAGE, IMAGE_FILE_LARGE_ADDRESS_AWARE ]
+sections:        
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  4096
+    VirtualSize:     1
+    SectionData:     C3
+symbols:         []
+...

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h

public:
   lldb_private::ArchSpec GetArchitecture() override;
 
   bool GetUUID(lldb_private::UUID *uuid) override;
 
   uint32_t GetDependentModules(lldb_private::FileSpecList &files) override;
 
   virtual lldb_private::Address GetEntryPointAddress() override;
 
+  lldb_private::Address GetBaseAddress() override;
+
   ObjectFile::Type CalculateType() override;
 
   ObjectFile::Strata CalculateStrata() override;
 
   //------------------------------------------------------------------
   // PluginInterface protocol
   //------------------------------------------------------------------
   lldb_private::ConstString GetPluginName() override;

source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

if (*offset_ptr < end_offset) {
         m_coff_header_opt.data_dirs.clear();
         m_coff_header_opt.data_dirs.resize(num_data_dir_entries);
         uint32_t i;
         for (i = 0; i < num_data_dir_entries; i++) {
           m_coff_header_opt.data_dirs[i].vmaddr = m_data.GetU32(offset_ptr);
           m_coff_header_opt.data_dirs[i].vmsize = m_data.GetU32(offset_ptr);
         }
 
-        m_file_offset = m_coff_header_opt.image_base;
         m_image_base = m_coff_header_opt.image_base;
       }
     }
   }
   // Make sure we are on track for section data which follows
   *offset_ptr = end_offset;
   return success;
 }
lldb_private::Address ObjectFilePECOFF::GetEntryPointAddress() {
 
   if (!section_list)
     m_entry_point_address.SetOffset(file_addr);
   else
     m_entry_point_address.ResolveAddressUsingFileSections(file_addr, section_list);
   return m_entry_point_address;
 }
 
+Address ObjectFilePECOFF::GetBaseAddress() {
+  return Address(GetSectionList()->GetSectionAtIndex(0), 0);
+}
+
 //----------------------------------------------------------------------
 // Dump
 //
 // Dump the specifics of the runtime file container (such as any headers
 // segments, sections, etc).
 //----------------------------------------------------------------------
 void ObjectFilePECOFF::Dump(Stream *s) {
   ModuleSP module_sp(GetModule());

source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

uint32_t SymbolFileNativePDB::CalculateAbilities() {
   abilities = kAllAbilities;
 
   if (m_index->dbi().isStripped())
     abilities &= ~(Blocks | LocalVariables);
   return abilities;
 }
 
 void SymbolFileNativePDB::InitializeObject() {
-  m_obj_load_address = m_obj_file->GetFileOffset();
+  m_obj_load_address = m_obj_file->GetBaseAddress().GetFileAddress();
   m_index->SetLoadAddress(m_obj_load_address);
   m_index->ParseSectionContribs();
 
   TypeSystem *ts = m_obj_file->GetModule()->GetTypeSystemForLanguage(
       lldb::eLanguageTypeC_plus_plus);
   if (ts)
     ts->SetSymbolFile(this);
 

source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp

while (auto table_up = enum_tables_up->getNext()) {
     default:
       break;
     }
   }
   return abilities;
 }
 
 void SymbolFilePDB::InitializeObject() {
-  lldb::addr_t obj_load_address = m_obj_file->GetFileOffset();
+  lldb::addr_t obj_load_address = m_obj_file->GetBaseAddress().GetFileAddress();
   lldbassert(obj_load_address && obj_load_address != LLDB_INVALID_ADDRESS);
   m_session_up->setLoadAddress(obj_load_address);
   if (!m_global_scope_up)
     m_global_scope_up = m_session_up->getGlobalScope();
   lldbassert(m_global_scope_up.get());
 
   TypeSystem *type_system =
       GetTypeSystemForLanguage(lldb::eLanguageTypeC_plus_plus);