Hi, Sergey, thanks for your efforts in adding new functionality to dbg extension! On 6/4/26 12:30, Sergey Kaplun wrote: > Branch:https://github.com/tarantool/luajit/tree/skaplun/gh-4808-gco-func-proto-bytecode > Issue:https://github.com/tarantool/tarantool/issues/4808 > > This patch set allows you to inspect bytecodes for a single instruction, > as well as for all bytecodes inside a function or its prototype via GDB > and LLDB. > > The first patch is a fixup for the LLDB indexing negative values. It may > affect the lj-stack command. The second patch fixes the DUALNUM mode > detection in LLDB. These fixes are required for the last patch in the > series. > > The third auxiliary patch is needed to introduce dumpers for GC objects > similar to TValues dumpers. Also, it may be useful during different > debugging scenarios, so it introduces the lj-gco command to > dump the GC object info in the same format as for a TValue slot. > > The last patch introduces 3 new commands: > * lj-bc -- dump single bytecode instruction > * lj-func -- dump all bytecode instructions for Lua function > or report type of C or F function > * lj-proto -- dump all bytecode instructions for the > prototype > > For example, we have the following Lua script named : it is worth adding this example to the appropriate commit message. What do you think? > | 1 local function mywhile(a) > | 2 local r = 0 > | 3 print(a) > | 4 while (a < 30) do > | 5 r = r + a * r/2 > | 6 end > | 7 return r > | 8 end > | 9 > | 10 local uvname1 = false > | 11 local uvname2 = false > | 12 local function myif(a) > | 13 local s1 = a + 4 > | 14 local s2 = s1 + 4 > | 15 uvname1 = "s10" > | 16 uvname2 = "s11" > | 17 print(a) > | 18 if a > 10 then > | 19 return a + s2 + s1 > | 20 else > | 21 return a - 10 - s2 - s1 > | 22 end > | 23 end > | 24 > | 25 local f1 = myif > | 26 local f2 = mywhile > | 27 myif(12) > | 28 mywhile(12) > > Assume we set a breakpoint at `lj_cf_print` (line 3). > The lj-stack output contains the following lines: > > | 0x40001970 [ ] VALUE: Lua function @ 0x400083c0, 0 upvalues, "@../tmp.lua":1 > | 0x40001968 [ ] VALUE: Lua function @ 0x40002148, 2 upvalues, "@../tmp.lua":12 > | ... > | 0x40001940 [ ] FRAME: [V] delta=1, Lua function @ 0x400084a0, 0 upvalues, "@../tmp.lua":0 > > The first one is `myif()` function the second is `mywhile()` and the > last one is function loaded via `dofile()`. > > The resulting output for the functions is the following: > > 1) > | (gdb) lj-func 0x400083c0 > | "@../tmp.lua":1-8 > | 0000 FUNCF rbase: 4 > | 0001 KSHORT dst: 1 lits: 0 > | 0002 GGET dst: 2 str: 0 ; string "print" @ 0x400037f0 > | 0003 MOV dst: 3 var: 0 > | 0004 CALL base: 2 lit: 1 lit: 2 > | 0005 KSHORT dst: 2 lits: 30 > | 0006 ISGE var: 0 var: 2 > | 0007 JMP rbase: 2 jump: => 0013 > | 0008 LOOP rbase: 2 jump: => 0013 > | 0009 MULVV dst: 2 var: 0 var: 1 > | 0010 DIVVN dst: 2 var: 2 num: 0 ; number 2 > | 0011 ADDVV dst: 1 var: 1 var: 2 > | 0012 JMP rbase: 2 jump: => 0005 > | 0013 RET1 rbase: 1 lit: 2 > > The report is the same as for the following command: > | lj-proto (GCproto *)(((char *)(((GCfuncL *)0x400083c0)->pc.ptr32))-sizeof(GCproto)) > > 2) > | (gdb) lj-func 0x40002148 > | "@../tmp.lua":12-23 > | 0000 FUNCF rbase: 5 > | 0001 ADDVN dst: 1 var: 0 num: 0 ; number 4 > | 0002 ADDVN dst: 2 var: 1 num: 0 ; number 4 > | 0003 USETS uv: 0 str: 0 ; 0x40002527 "uvname1" ; string "s10" @ 0x40002298 > | 0004 USETS uv: 1 str: 1 ; 0x4000252f "uvname2" ; string "s11" @ 0x400022b8 > | 0005 GGET dst: 3 str: 2 ; string "print" @ 0x400037f0 > | 0006 MOV dst: 4 var: 0 > | 0007 CALL base: 3 lit: 1 lit: 2 > | 0008 KSHORT dst: 3 lits: 10 > | 0009 ISGE var: 3 var: 0 > | 0010 JMP rbase: 3 jump: => 0015 > | 0011 ADDVV dst: 3 var: 0 var: 2 > | 0012 ADDVV dst: 3 var: 3 var: 1 > | 0013 RET1 rbase: 3 lit: 2 > | 0014 JMP rbase: 3 jump: => 0019 > | 0015 SUBVN dst: 3 var: 0 num: 1 ; number 10 > | 0016 SUBVV dst: 3 var: 3 var: 2 > | 0017 SUBVV dst: 3 var: 3 var: 1 > | 0018 RET1 rbase: 3 lit: 2 > | 0019 RET0 rbase: 0 lit: 1 > > 3) > > | (gdb) lj-func 0x400084a0 > | "@../tmp.lua":0-30 > | 0000 FUNCV rbase: 8 > | 0001 FNEW dst: 0 func: 0 ; "@../tmp.lua":1 > | 0002 KPRI dst: 1 pri: 1 > | 0003 KPRI dst: 2 pri: 1 > | 0004 FNEW dst: 3 func: 1 ; "@../tmp.lua":12 > | 0005 MOV dst: 4 var: 3 > | 0006 MOV dst: 5 var: 0 > | 0007 MOV dst: 6 var: 3 > | 0008 KSHORT dst: 7 lits: 12 > | 0009 CALL base: 6 lit: 1 lit: 2 > | 0010 MOV dst: 6 var: 0 > | 0011 KSHORT dst: 7 lits: 12 > | 0012 CALL base: 6 lit: 1 lit: 2 > | 0013 UCLO rbase: 0 jump: => 0014 > | 0014 RET0 rbase: 0 lit: 1 > > The single bytecode instruction may be useful when you debug the VM: > > | (gdb) b lj_BC_ISGE > | Breakpoint 2 at 0x5555555f0a08 > | (gdb) c > | Continuing. > | Breakpoint 2, 0x00005555555f0a08 in lj_BC_ISGE () > | (gdb) lj-bc $rbx # PC refers __the next instruction__ > | JMP rbase: 3 jump: +5 > | (gdb) lj-bc ((BCIns *)$rbx) - 1 # current instruction > | ISGE var: 3 var: 0 > > > Sergey Kaplun (4): > dbg: fix lj-stack command for LLDB > dbg: fix DUALNUM detection for LLDB > dbg: introduce lj-gco command > dbg: introduce lj-bc, lj-func and lj-proto dumpers > > src/luajit_dbg.py | 650 ++++++++++++++++-- > .../debug-extension-tests.py | 203 +++++- > 2 files changed, 757 insertions(+), 96 deletions(-) >