Don't pack the structs of the jit debug interface

[tberghammer]

Summary

Don't pack the structs of the jit debug interface

None of the documentation mentions that the entries are packed structs and also none of the other implementation I found pack them.

LLVM implementation: https://github.com/llvm-mirror/llvm/blob/master/lib/ExecutionEngine/GDBRegistrationListener.cpp

[loladiro]

I don't think that was part of the code I originally had, but I suppose this was added for 32bit compatibility? Would this do the right thing with a 32bit target?

[tberghammer]

I hit the problem when debugging an arm32 target from an x86_64 host and this CL fixes that issue. It will break if a 32bit target use the same "pragma pack" attribute I just removed.

The change have no effect for 64bit targets because symfile_size will be 8 byte aligned independently of the "pragma pack" (because all previous member is 8 byte).

[loladiro]

Ok, I see. Yes, I agree with this change. LGTM.

[tfiala]

Sorry, late to the party. All the same, LGTM.

lldb/trunk/source/Plugins/JITLoader/GDB/JITLoaderGDB.cpp

 //------------------------------------------------------------------
 typedef enum
 {
     JIT_NOACTION = 0,
     JIT_REGISTER_FN,
     JIT_UNREGISTER_FN
 } jit_actions_t;
 
-#pragma pack(push, 4)
 template <typename ptr_t>
 struct jit_code_entry
 {
     ptr_t    next_entry; // pointer
     ptr_t    prev_entry; // pointer
     ptr_t    symfile_addr; // pointer
     uint64_t symfile_size;
 };
 template <typename ptr_t>
 struct jit_descriptor
 {
     uint32_t version;
     uint32_t action_flag; // Values are jit_action_t
     ptr_t    relevant_entry; // pointer
     ptr_t    first_entry; // pointer
 };
-#pragma pack(pop)
 
 JITLoaderGDB::JITLoaderGDB (lldb_private::Process *process) :
     JITLoader(process),
     m_jit_objects(),
     m_jit_break_id(LLDB_INVALID_BREAK_ID),
     m_jit_descriptor_addr(LLDB_INVALID_ADDRESS)
 {
 }