Userspace MIPS emulator. Mostly a toy, but there's the tracemips utility which creates user-friendly instruction traces - notice the string fetching, and the stack trace in each line (scroll to the right, it's too wide for the GitHub's default display):
120776d2c: de320008 ld s2,8(s1) # s2 := 0x00007fffffffef05 ("SHELL=/bin/bash") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776e40: 1640ffb3 bne s2,zero,-77 # taken # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776e44: 66310008 daddiu s1,s1,8 # s1 := 0x00007fffffffa9e8 (140737488333288) # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d10: 0240202d daddu a0,s2,zero # a0 := 0x00007fffffffef05 ("SHELL=/bin/bash") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d14: 0200282d daddu a1,s0,zero # a1 := 0x000000012094ffd8 ("MALLOC_CONF") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d18: 0260302d daddu a2,s3,zero # a2 := 0x000000000000000b (11) # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d1c: df99ff48 ld t9,-184(gp) # t9 := 0x000000012077a0e0 ("g") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d20: 0320f809 jalr ra,t9 # ra := 0x0000000120776d28 ("T@") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d24: 00000000 sll zero,zero,0 # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
12077a0e0: 67bdfff0 daddiu sp,sp,-16 # sp := 0x00007fffffffa308 (140737488331528) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0e4: ffbc0000 sd gp,0(sp) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0e8: 3c1c0026 lui gp,38 # gp := 0x0000000000260000 (2490368) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0ec: 0399e02d daddu gp,gp,t9 # gp := 0x00000001209da0e0 (4842168544) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0f0: 679c68f0 daddiu gp,gp,26864 # gp := 0x00000001209e09d0 (4842195408) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0f4: 10c0000f beq a2,zero,15 # not taken # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0f8: 0000102d daddu v0,zero,zero # v0 := 000000000000000000 (0) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a0fc: 00000000 sll zero,zero,0 # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a100: 80830000 lb v1,0(a0) # v1 := 0x0000000000000053 (83) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a104: 80a20000 lb v0,0(a1) # v0 := 0x000000000000004d (77) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a108: 10430005 beq v0,v1,5 # not taken # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a10c: 64a50001 daddiu a1,a1,1 # a1 := 0x000000012094ffd9 ("ALLOC_CONF") # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a110: 90830000 lbu v1,0(a0) # v1 := 0x0000000000000053 (83) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a114: 90a2ffff lbu v0,-1(a1) # v0 := 0x000000000000004d (77) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a118: 10000006 beq zero,zero,6 # taken # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a11c: 00621023 subu v0,v1,v0 # v0 := 0x0000000000000006 (6) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a134: dfbc0000 ld gp,0(sp) # gp := 0x0000000120a03868 (4842338408) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a138: 03e00008 jr ra # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
12077a13c: 67bd0010 daddiu sp,sp,16 # sp := 0x00007fffffffa318 (140737488331544) # strncmp getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _in
120776d28: 54400045 bnel v0,zero,69 # taken # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776d2c: de320008 ld s2,8(s1) # s2 := 0x00007fffffffef15 ("TMUX=/tmp/tmux-381") # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s
120776e40: 1640ffb3 bne s2,zero,-77 # taken # getenv malloc_init_hard_a0_locked malloc_init jemalloc_constructor __do_global_ctors_aux _init __s