The invention is directed to compounds of formula (I), wherein R1, R2, R3, R4,R5, R6, R7a, R7b, W, G1, G2, a, b, c, d and m are as defined in thespecification, or a pharmaceutically acceptable salt or solvate orstereoisomer thereof. The invention is also directed to pharmaceuticalcompositions comprising such compounds; methods of using such compounds; andprocess and intermediates for preparing such compounds.