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Fix ObjectFileElf::GetEntryPointAddress() 

ELF object files do not implicitly have a symbol named "start" as an entry
point.  For example, on Linux it is often named "_start", but can be trivially
set to any symbol by passing an --entry argument to the linker.

Use the ELF header to determine the entry point and resolve the associated
section based on that address.

Also, update the linux dynamic loader to call GetEntryPointAddress instead of
GetEntryPoint.

llvm-svn: 127218
This commit is contained in:
Stephen Wilson 2011-03-08 04:12:15 +00:00
parent 97c250405b
commit d126c8cc5a
2 changed files with 21 additions and 21 deletions
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2
lldb/source/Plugins/DynamicLoader/Linux-DYLD/DynamicLoaderLinuxDYLD.cpp
View File

@ -353,7 +353,7 @@ DynamicLoaderLinuxDYLD::ComputeLoadOffset()
ModuleSP module = m_process->GetTarget().GetExecutableModule();
ObjectFile *exe = module->GetObjectFile();
Address file_entry = exe->GetEntryPoint();
Address file_entry = exe->GetEntryPointAddress();
if (!file_entry.IsValid())
return LLDB_INVALID_ADDRESS;

40
lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
View File

@ -272,27 +272,27 @@ ObjectFileELF::GetImageInfoAddress()
lldb_private::Address
ObjectFileELF::GetEntryPointAddress ()
{
// If the object file is not an executable it can't hold the entry point. m_entry_point_address
// is initialized to an invalid address, so we can just return that.
// If m_entry_point_address is valid it means we've found it already, so return the cached value.
if (!IsExecutable() || m_entry_point_address.IsValid())
return m_entry_point_address;
// FIXME: This is just looking for the "start" symbol, but that will fail if "start" is stripped.
// There's probably a better way in ELF to find the start address of an executable module.
SymbolContextList contexts;
SymbolContext context;
if (!m_module->FindSymbolsWithNameAndType(ConstString ("start"), lldb::eSymbolTypeCode, contexts))
return m_entry_point_address;
contexts.GetContextAtIndex(0, context);
m_entry_point_address = context.symbol->GetValue();
return m_entry_point_address;
SectionList *sections;
addr_t offset;
if (m_entry_point_address.IsValid())
return m_entry_point_address;
if (!ParseHeader() || !IsExecutable())
return m_entry_point_address;
sections = GetSectionList();
offset = m_header.e_entry;
if (!sections)
{
m_entry_point_address.SetOffset(offset);
return m_entry_point_address;
}
m_entry_point_address.ResolveAddressUsingFileSections(offset, sections);
return m_entry_point_address;
}
//----------------------------------------------------------------------