Reduce memory consumption.

include/base/SMPFunction.h

src/base/SMPBasicBlock.cpp

src/base/SMPFunction.cpp

src/base/SMPInstr.cpp

src/interfaces/irdb/STARS_IRDB_Function.cpp

src/interfaces/irdb/STARS_IRDB_Instruction.cpp

src/interfaces/irdb/STARS_IRDB_Interface.cpp