I'd like to ask for some clarification relating to DW_AT_entry_pc. Here is the relevant section from the DWARF-5 spec for reference:
2.18 Entry Address The entry or first executable instruction generated for an entity, if applicable, is often the lowest addressed instruction of a contiguous range of instructions. In other cases, the entry address needs to be specified explicitly. Any debugging information entry describing an entity that has a range of code addresses, which includes compilation units, module initialization, subroutines, lexical blocks, try/catch blocks, and the like, may have a DW_AT_entry_pc attribute to indicate the entry address which is the address of the instruction where execution begins within that range of addresses. If the value of the DW_AT_entry_pc attribute is of class address that address is the entry address; or, if it is of class constant, the value is an unsigned integer offset which, when added to the base address of the function, gives the entry address. If no DW_AT_entry_pc attribute is present, then the entry address is assumed to be the same as the base address of the containing scope. I am slightly confused by two parts of this. First, this: "...if it is of class constant, the value is an unsigned integer offset which, when added to the base address of the function, gives the entry address." What does 'of the function' mean in this context? I wonder if this possibly means the base address of the DIE which contains the DW_AT_entry_pc itself? Or should I be looking up the DIE hierarchy some specific DIE type? Next this: "If no DW_AT_entry_pc attribute is present, then the entry address is assumed to be the same as the base address of the containing scope." My very literal reading of this is that "containing scope" must be the DIE which contains the DIE which is missing the DW_AT_entry_pc, i.e. the parent of the DIE we are currently looking at. I got there because DW_AT_entry_pc is missing, so nothing contains it. Therefore the only thing that can be contained is the DIE we are currently considering. However, I suspect this might not be the intended meaning. My less literal interpretation is that we should use the base address of the DIE which is missing the DW_AT_entry_pc. Any guidance is gratefully received. Thanks, Andrew -- Dwarf-discuss mailing list Dwarf-discuss@lists.dwarfstd.org https://lists.dwarfstd.org/mailman/listinfo/dwarf-discuss
