[LLVMdev] Getting the Debugging JIT-ed Code with GDB example to work
Zach Devito
zdevito at stanford.edu
Tue Mar 25 18:44:13 PDT 2014
I tested it with the symbols enabled for lli and it still doesn't work.
Below is the assembly for GDBJITRegistrar::registerObject containing the
inlined body of NotifyDebugger. It looks like the call to
__jit_debug_register_code was inlined away despite being marked with
LLVM_ATTRIBUTE_NOINLINE. LLVM was compiled with the following GCC:
zdevito at derp:~/terra/tests$ gcc --version
> gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
> Copyright (C) 2011 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Maybe the LLVM_ATTRIBUTE_NOINLINE macro is defined wrong, or the compiler
is ignoring it?
Zach
Dump of assembler code for function (anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&):
> 0x0000000000b1eba0 <+0>: push rbp
> 0x0000000000b1eba1 <+1>: push r15
> 0x0000000000b1eba3 <+3>: push r14
> 0x0000000000b1eba5 <+5>: push r13
> 0x0000000000b1eba7 <+7>: push r12
> 0x0000000000b1eba9 <+9>: push rbx
> 0x0000000000b1ebaa <+10>: sub rsp,0x28
> 0x0000000000b1ebae <+14>: mov r14,rdi
> 0x0000000000b1ebb1 <+17>: mov rax,QWORD PTR [rsi+0x8]
> 0x0000000000b1ebb5 <+21>: mov r13,QWORD PTR [rax+0x8]
> 0x0000000000b1ebb9 <+25>: mov QWORD PTR [rsp+0x8],r13
> 0x0000000000b1ebbe <+30>: test r13,r13
> 0x0000000000b1ebc1 <+33>: je 0xb1edcf <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+559>
> 0x0000000000b1ebc7 <+39>: mov rax,QWORD PTR [rax+0x10]
> 0x0000000000b1ebcb <+43>: sub rax,r13
> 0x0000000000b1ebce <+46>: mov QWORD PTR [rsp],rax
> 0x0000000000b1ebd2 <+50>: mov r15,QWORD PTR [r14+0x8]
> 0x0000000000b1ebd6 <+54>: mov ebp,DWORD PTR [r14+0x18]
> 0x0000000000b1ebda <+58>: add r14,0x8
> 0x0000000000b1ebde <+62>: test rbp,rbp
> 0x0000000000b1ebe1 <+65>: je 0xb1ec3f <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+159>
> 0x0000000000b1ebe3 <+67>: mov rax,r13
> 0x0000000000b1ebe6 <+70>: or rax,0x4
> 0x0000000000b1ebea <+74>: cmp rax,0xfffffffffffffffc
> 0x0000000000b1ebee <+78>: je 0xb1ee1e <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+638>
> 0x0000000000b1ebf4 <+84>: mov ecx,r13d
> 0x0000000000b1ebf7 <+87>: shr ecx,0x9
> 0x0000000000b1ebfa <+90>: mov eax,r13d
> 0x0000000000b1ebfd <+93>: shr eax,0x4
> 0x0000000000b1ec00 <+96>: xor eax,ecx
> 0x0000000000b1ec02 <+98>: lea ecx,[rbp-0x1]
> 0x0000000000b1ec05 <+101>: and eax,ecx
> 0x0000000000b1ec07 <+103>: lea rdx,[rax+rax*2]
> 0x0000000000b1ec0b <+107>: mov rsi,QWORD PTR [r15+rdx*8]
> 0x0000000000b1ec0f <+111>: cmp r13,rsi
> 0x0000000000b1ec12 <+114>: je 0xb1ec4a <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+170>
> 0x0000000000b1ec14 <+116>: mov edx,0x1
> 0x0000000000b1ec19 <+121>: nop DWORD PTR [rax+0x0]
> 0x0000000000b1ec20 <+128>: cmp rsi,0xfffffffffffffffc
> 0x0000000000b1ec24 <+132>: je 0xb1ec3f <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+159>
> 0x0000000000b1ec26 <+134>: add eax,edx
> 0x0000000000b1ec28 <+136>: and eax,ecx
> 0x0000000000b1ec2a <+138>: lea rdi,[rax+rax*2]
> 0x0000000000b1ec2e <+142>: mov rsi,QWORD PTR [r15+rdi*8]
> 0x0000000000b1ec32 <+146>: inc edx
> 0x0000000000b1ec34 <+148>: cmp r13,rsi
> 0x0000000000b1ec37 <+151>: jne 0xb1ec20 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+128>
> 0x0000000000b1ec39 <+153>: lea rax,[r15+rdi*8]
> 0x0000000000b1ec3d <+157>: jmp 0xb1ec4e <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+174>
> 0x0000000000b1ec3f <+159>: lea rax,[rbp+rbp*2+0x0]
> 0x0000000000b1ec44 <+164>: lea rax,[r15+rax*8]
> 0x0000000000b1ec48 <+168>: jmp 0xb1ec4e <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+174>
> 0x0000000000b1ec4a <+170>: lea rax,[r15+rdx*8]
> 0x0000000000b1ec4e <+174>: lea rcx,[rbp+rbp*2+0x0]
> 0x0000000000b1ec53 <+179>: lea rcx,[r15+rcx*8]
> 0x0000000000b1ec57 <+183>: cmp rax,rcx
> 0x0000000000b1ec5a <+186>: jne 0xb1edee <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+590>
> 0x0000000000b1ec60 <+192>: mov edi,0x20
> 0x0000000000b1ec65 <+197>: call 0x4e8120 <_Znwm at plt>
> 0x0000000000b1ec6a <+202>: mov r12,rax
> 0x0000000000b1ec6d <+205>: mov QWORD PTR [r12+0x18],0x0
> 0x0000000000b1ec76 <+214>: mov QWORD PTR [r12+0x10],0x0
> 0x0000000000b1ec7f <+223>: mov QWORD PTR [r12+0x8],0x0
> 0x0000000000b1ec88 <+232>: mov QWORD PTR [r12],0x0
> 0x0000000000b1ec90 <+240>: test r12,r12
> 0x0000000000b1ec93 <+243>: je 0xb1ee0d <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+621>
> 0x0000000000b1ec99 <+249>: mov QWORD PTR [r12+0x10],r13
> 0x0000000000b1ec9e <+254>: mov rax,QWORD PTR [rsp]
> 0x0000000000b1eca2 <+258>: mov QWORD PTR [r12+0x18],rax
> 0x0000000000b1eca7 <+263>: xor eax,eax
> 0x0000000000b1eca9 <+265>: test ebp,ebp
> 0x0000000000b1ecab <+267>: je 0xb1ed2b <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+395>
> 0x0000000000b1ecad <+269>: mov rax,r13
> 0x0000000000b1ecb0 <+272>: or rax,0x4
> 0x0000000000b1ecb4 <+276>: cmp rax,0xfffffffffffffffc
> 0x0000000000b1ecb8 <+280>: je 0xb1ee1e <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+638>
> 0x0000000000b1ecbe <+286>: mov eax,r13d
> 0x0000000000b1ecc1 <+289>: shr eax,0x9
> 0x0000000000b1ecc4 <+292>: mov ecx,r13d
> 0x0000000000b1ecc7 <+295>: shr ecx,0x4
> 0x0000000000b1ecca <+298>: xor ecx,eax
> 0x0000000000b1eccc <+300>: dec ebp
> 0x0000000000b1ecce <+302>: and ecx,ebp
> 0x0000000000b1ecd0 <+304>: lea rdx,[rcx+rcx*2]
> 0x0000000000b1ecd4 <+308>: lea rax,[r15+rdx*8]
> 0x0000000000b1ecd8 <+312>: mov rdi,QWORD PTR [r15+rdx*8]
> 0x0000000000b1ecdc <+316>: cmp r13,rdi
> 0x0000000000b1ecdf <+319>: je 0xb1ed65 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+453>
> 0x0000000000b1ece5 <+325>: xor edx,edx
> 0x0000000000b1ece7 <+327>: mov esi,0x1
> 0x0000000000b1ecec <+332>: nop DWORD PTR [rax+0x0]
> 0x0000000000b1ecf0 <+336>: cmp rdi,0xfffffffffffffffc
> 0x0000000000b1ecf4 <+340>: je 0xb1ed24 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+388>
> 0x0000000000b1ecf6 <+342>: add ecx,esi
> 0x0000000000b1ecf8 <+344>: and ecx,ebp
> 0x0000000000b1ecfa <+346>: test rdx,rdx
> 0x0000000000b1ecfd <+349>: sete r8b
> 0x0000000000b1ed01 <+353>: cmp rdi,0xfffffffffffffff8
> 0x0000000000b1ed05 <+357>: sete bl
> 0x0000000000b1ed08 <+360>: test r8b,bl
> 0x0000000000b1ed0b <+363>: cmovne rdx,rax
> 0x0000000000b1ed0f <+367>: lea rdi,[rcx+rcx*2]
> 0x0000000000b1ed13 <+371>: lea rax,[r15+rdi*8]
> 0x0000000000b1ed17 <+375>: mov rdi,QWORD PTR [r15+rdi*8]
> 0x0000000000b1ed1b <+379>: inc esi
> 0x0000000000b1ed1d <+381>: cmp r13,rdi
> 0x0000000000b1ed20 <+384>: jne 0xb1ecf0 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+336>
> 0x0000000000b1ed22 <+386>: jmp 0xb1ed65 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+453>
> 0x0000000000b1ed24 <+388>: test rdx,rdx
> 0x0000000000b1ed27 <+391>: cmovne rax,rdx
> 0x0000000000b1ed2b <+395>: xorps xmm0,xmm0
> 0x0000000000b1ed2e <+398>: movaps XMMWORD PTR [rsp+0x10],xmm0
> 0x0000000000b1ed33 <+403>: lea rsi,[rsp+0x8]
> 0x0000000000b1ed38 <+408>: mov rdi,r14
> 0x0000000000b1ed3b <+411>: mov rdx,rax
> 0x0000000000b1ed3e <+414>: call 0xb1f150
> <llvm::DenseMapBase<llvm::DenseMap<char const*, std::pair<unsigned long,
> jit_code_entry*>, llvm::DenseMapInfo<char const*> >, char const*,
> std::pair<unsigned long, jit_code_entry*>, llvm::DenseMapInfo<char const*>
> >::InsertIntoBucketImpl(char const* const&, std::pair<char const*,
> std::pair<unsigned long, jit_code_entry*> >*)>
> 0x0000000000b1ed43 <+419>: mov rcx,QWORD PTR [rsp+0x8]
> 0x0000000000b1ed48 <+424>: mov QWORD PTR [rax],rcx
> 0x0000000000b1ed4b <+427>: mov rcx,rax
> 0x0000000000b1ed4e <+430>: add rcx,0x8
> 0x0000000000b1ed52 <+434>: je 0xb1ed65 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+453>
> 0x0000000000b1ed54 <+436>: mov rdx,QWORD PTR [rsp+0x10]
> 0x0000000000b1ed59 <+441>: mov rsi,QWORD PTR [rsp+0x18]
> 0x0000000000b1ed5e <+446>: mov QWORD PTR [rcx+0x8],rsi
> 0x0000000000b1ed62 <+450>: mov QWORD PTR [rcx],rdx
> 0x0000000000b1ed65 <+453>: mov rcx,QWORD PTR [rsp]
> 0x0000000000b1ed69 <+457>: mov QWORD PTR [rax+0x8],rcx
> 0x0000000000b1ed6d <+461>: mov QWORD PTR [rax+0x10],r12
> => 0x0000000000b1ed71 <+465>: lea rdi,[rip+0x707310] #
> 0x1226088 <_ZN12_GLOBAL__N_112JITDebugLockE>
> 0x0000000000b1ed78 <+472>: call 0xca3810
> <llvm::sys::MutexImpl::acquire()>
> 0x0000000000b1ed7d <+477>: mov rax,QWORD PTR [rip+0x6fdeb4]
> # 0x121cc38
> 0x0000000000b1ed84 <+484>: mov DWORD PTR [rax+0x4],0x1
> 0x0000000000b1ed8b <+491>: mov QWORD PTR [r12+0x8],0x0
> 0x0000000000b1ed94 <+500>: mov rax,QWORD PTR [rax+0x10]
> 0x0000000000b1ed98 <+504>: mov QWORD PTR [r12],rax
> 0x0000000000b1ed9c <+508>: test rax,rax
> 0x0000000000b1ed9f <+511>: je 0xb1eda5 <(anonymous
> namespace)::GDBJITRegistrar::registerObject(llvm::ObjectBuffer const&)+517>
> 0x0000000000b1eda1 <+513>: mov QWORD PTR [rax+0x8],r12
> 0x0000000000b1eda5 <+517>: mov rax,QWORD PTR [rip+0x6fde8c]
> # 0x121cc38
> 0x0000000000b1edac <+524>: mov QWORD PTR [rax+0x10],r12
> 0x0000000000b1edb0 <+528>: mov QWORD PTR [rax+0x8],r12
> 0x0000000000b1edb4 <+532>: lea rdi,[rip+0x7072cd] #
> 0x1226088 <_ZN12_GLOBAL__N_112JITDebugLockE>
> 0x0000000000b1edbb <+539>: call 0xca3850
> <llvm::sys::MutexImpl::release()>
> 0x0000000000b1edc0 <+544>: add rsp,0x28
> 0x0000000000b1edc4 <+548>: pop rbx
> 0x0000000000b1edc5 <+549>: pop r12
> 0x0000000000b1edc7 <+551>: pop r13
> 0x0000000000b1edc9 <+553>: pop r14
> 0x0000000000b1edcb <+555>: pop r15
> 0x0000000000b1edcd <+557>: pop rbp
> 0x0000000000b1edce <+558>: ret
> 0x0000000000b1edcf <+559>: lea rdi,[rip+0x35f9a9] # 0xe7e77f
> 0x0000000000b1edd6 <+566>: lea rsi,[rip+0x35f6fc] # 0xe7e4d9
> 0x0000000000b1eddd <+573>: lea rcx,[rip+0x35f9da] # 0xe7e7be
> 0x0000000000b1ede4 <+580>: mov edx,0x84
> 0x0000000000b1ede9 <+585>: call 0x4e7ef0 <__assert_fail at plt>
> 0x0000000000b1edee <+590>: lea rdi,[rip+0x35fa29] # 0xe7e81e
> 0x0000000000b1edf5 <+597>: lea rsi,[rip+0x35f6dd] # 0xe7e4d9
> 0x0000000000b1edfc <+604>: lea rcx,[rip+0x35f9bb] # 0xe7e7be
> 0x0000000000b1ee03 <+611>: mov edx,0x86
> 0x0000000000b1ee08 <+616>: call 0x4e7ef0 <__assert_fail at plt>
> 0x0000000000b1ee0d <+621>: lea rdi,[rip+0x35fa73] # 0xe7e887
> 0x0000000000b1ee14 <+628>: mov esi,0x1
> 0x0000000000b1ee19 <+633>: call 0xc9dbe0
> <llvm::report_fatal_error(char const*, bool)>
> 0x0000000000b1ee1e <+638>: lea rdi,[rip+0x1a8998] # 0xcc77bd
> 0x0000000000b1ee25 <+645>: lea rsi,[rip+0x1a8045] # 0xcc6e71
> 0x0000000000b1ee2c <+652>: lea rcx,[rip+0x35f722] # 0xe7e555
> 0x0000000000b1ee33 <+659>: mov edx,0x1e0
> 0x0000000000b1ee38 <+664>: call 0x4e7ef0 <__assert_fail at plt>
On Tue, Mar 25, 2014 at 4:19 PM, Kaylor, Andrew <andrew.kaylor at intel.com>wrote:
> Actually, put aside what I said in my previous reply for a second.
>
>
>
> I just noticed in your output below that GDB didn't have symbols for lli.
> That's probably the heart of your problem. GDB relies on hooking a known
> function to get the JITed code registration to work. Since it didn't find
> symbols for lli, it won't find the hook function.
>
>
>
> You'll need to use a build of lli with symbols to make this work.
>
>
>
> -Andy
>
>
>
> *From:* llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] *On
> Behalf Of *Zach Devito
> *Sent:* Tuesday, March 25, 2014 1:35 PM
> *To:* LLVM Developers Mailing List
> *Subject:* [LLVMdev] Getting the Debugging JIT-ed Code with GDB example
> to work
>
>
>
> I'm trying to run the example described at:
>
>
>
> http://llvm.org/docs/DebuggingJITedCode.html
>
>
>
> I followed the sample command line session (below, with versions numbers
> for everything), but gdb doesn't stop at the breakpoints as described. Any
> idea what is wrong?
>
>
>
> Thanks,
>
>
>
> Zach
>
>
>
>
>
> zdevito at derp:~/terra/tests$
> ~/clang+llvm-3.4-x86_64-unknown-ubuntu12.04/bin/clang -cc1 -O0 -g
> -emit-llvm showdebug.c
> zdevito at derp:~/terra/tests$ gdb --args
> ~/clang+llvm-3.4-x86_64-unknown-ubuntu12.04/bin/lli -use-mcjit showdebug.ll
> 5
> GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2) 7.4-2012.04
> Copyright (C) 2012 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <
> http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law. Type "show copying"
> and "show warranty" for details.
> This GDB was configured as "x86_64-linux-gnu".
> For bug reporting instructions, please see:
> <http://bugs.launchpad.net/gdb-linaro/>...
> Reading symbols from
> /home/zdevito/clang+llvm-3.4-x86_64-unknown-ubuntu12.04/bin/lli...(no
> debugging symbols found)...done.
> (gdb) b showdebug.c:6
> No symbol table is loaded. Use the "file" command.
> Make breakpoint pending on future shared library load? (y or [n]) y
> Breakpoint 1 (showdebug.c:6) pending.
> (gdb) r
> Starting program:
> /home/zdevito/clang+llvm-3.4-x86_64-unknown-ubuntu12.04/bin/lli -use-mcjit
> showdebug.ll 5
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
> [Inferior 1 (process 8538) exited with code 0170]
> (gdb)
>
>
>
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