Using either Delphi 2007+ or Lazarus(Win64) I'm looking for a way to determine if a dll is compiled as x64 or x86?
You should read and parse PE header.
Like this:
function Isx64(const Strm: TStream): Boolean;
const
IMAGE_FILE_MACHINE_I386 = $014c; // Intel x86
IMAGE_FILE_MACHINE_IA64 = $0200; // Intel Itanium Processor Family (IPF)
IMAGE_FILE_MACHINE_AMD64 = $8664; // x64 (AMD64 or EM64T)
// You'll unlikely encounter the things below:
IMAGE_FILE_MACHINE_R3000_BE = $160; // MIPS big-endian
IMAGE_FILE_MACHINE_R3000 = $162; // MIPS little-endian, 0x160 big-endian
IMAGE_FILE_MACHINE_R4000 = $166; // MIPS little-endian
IMAGE_FILE_MACHINE_R10000 = $168; // MIPS little-endian
IMAGE_FILE_MACHINE_ALPHA = $184; // Alpha_AXP }
IMAGE_FILE_MACHINE_POWERPC = $1F0; // IBM PowerPC Little-Endian
var
Header: TImageDosHeader;
ImageNtHeaders: TImageNtHeaders;
begin
Strm.ReadBuffer(Header, SizeOf(Header));
if (Header.e_magic <> IMAGE_DOS_SIGNATURE) or
(Header._lfanew = 0) then
raise Exception.Create('Invalid executable');
Strm.Position := Header._lfanew;
Strm.ReadBuffer(ImageNtHeaders, SizeOf(ImageNtHeaders));
if ImageNtHeaders.Signature <> IMAGE_NT_SIGNATURE then
raise Exception.Create('Invalid executable');
Result := ImageNtHeaders.FileHeader.Machine <> IMAGE_FILE_MACHINE_I386;
end;