Green’s Dictionary of Slang

(US) to put up against a wall and shoot.

[1909		‘O. Henry’ Roads of Destiny 354: You ’ve got to back up against th’ ’dobe, old man. [...] You’re to be stood against a ’dobe wall and shot in two or three weeks].
1929		(con. 1875) J.F. Dobie Vaquero of the Brush Country 70: His idea of inspiring respect for law was to ‘’dobe-wall’ the lawless — stand them up against an adobe wall and shoot them.
1935		C.G. Finney Circus of Dr Lao 87: I seen Pancho Villa ’dobe wall a bunch of guys once.