ravitheja added a comment. so regarding this particular situation I want to give little more insight -> It starts out from here
0x40143a <+346>: movabsq $0x403e32, %rdi ; imm = 0x403E32 0x401444 <+356>: movb $0x0, %al 0x401446 <+358>: callq 0x400d30 ; symbol stub for: printf 0x40144b <+363>: movq 0x6071c0, %rdi 0x401453 <+371>: movl %eax, -0xdc(%rbp) ->0x401459 <+377>: callq 0x400ed0 ; symbol stub for: fflush 0x40145e <+382>: movl $0x40, %esi 0x401463 <+387>: leaq -0xb0(%rbp), %rdi 0x40146a <+394>: movq 0x607158, %rdx 0x401472 <+402>: movl %eax, -0xe0(%rbp) (lldb) disassemble a.out`fflush: -> 0x400ed0 <+0>: jmpq *0x206212(%rip) ; _GLOBAL_OFFSET_TABLE_ + 232 0x400ed6 <+6>: pushq $0x1a 0x400edb <+11>: jmp 0x400d20 (lldb) disassemble -> 0x400d20: pushq 0x2062e2(%rip) ; _GLOBAL_OFFSET_TABLE_ + 8 0x400d26: jmpq *0x2062e4(%rip) ; _GLOBAL_OFFSET_TABLE_ + 16 I think this jump goes to fflush. ld-linux-x86-64.so.2`___lldb_unnamed_symbol95$$ld-linux-x86-64.so.2: 0x7ffff7df04a0 <+0>: subq $0x38, %rsp -> The testcase tries to unwind out of here and fails. 0x7ffff7df04a4 <+4>: movq %rax, (%rsp) 0x7ffff7df04a8 <+8>: movq %rcx, 0x8(%rsp) 0x7ffff7df04ad <+13>: movq %rdx, 0x10(%rsp) 0x7ffff7df04b2 <+18>: movq %rsi, 0x18(%rsp) 0x7ffff7df04b7 <+23>: movq %rdi, 0x20(%rsp) 0x7ffff7df04bc <+28>: movq %r8, 0x28(%rsp) 0x7ffff7df04c1 <+33>: movq %r9, 0x30(%rsp) 0x7ffff7df04c6 <+38>: movq 0x40(%rsp), %rsi Now as you can see, from inside fflush its not possible for the assembly unwind to figure out the situation. @jasonmolenda The functions I posted in the lldb-dev are the same, here i am just posting how it got there. There is eh_frame information for these functions, that is able to correctly point out the CFA. lldb) image show-unwind --address 0x7ffff7df04a0 UNWIND PLANS for ld-linux-x86-64.so.2`___lldb_unnamed_symbol95$$ld-linux-x86-64.so.2 (start addr 0x7ffff7df04a0) Asynchronous (not restricted to call-sites) UnwindPlan is 'assembly insn profiling' Synchronous (restricted to call-sites) UnwindPlan is 'eh_frame CFI' Assembly language inspection UnwindPlan: This UnwindPlan originally sourced from assembly insn profiling This UnwindPlan is sourced from the compiler: no. This UnwindPlan is valid at all instruction locations: yes. Address range of this UnwindPlan: [ld-linux-x86-64.so.2..text + 88512-0x0000000000015a30) row[0]: 0: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8] row[1]: 4: CFA=rsp+64 => rsp=CFA+0 rip=[CFA-8] row[2]: 94: CFA=rsp -8 => rsp=CFA+0 rip=[CFA-8] eh_frame UnwindPlan: This UnwindPlan originally sourced from eh_frame CFI This UnwindPlan is sourced from the compiler: yes. This UnwindPlan is valid at all instruction locations: no. Address range of this UnwindPlan: [ld-linux-x86-64.so.2..text + 88512-0x0000000000015a21) row[0]: 0: CFA=rsp+24 => rip=[CFA-8] row[1]: 4: CFA=rsp+80 => rip=[CFA-8] row[2]: 94: CFA=rsp +8 => rip=[CFA-8] Arch default UnwindPlan: This UnwindPlan originally sourced from x86_64 default unwind plan This UnwindPlan is sourced from the compiler: no. This UnwindPlan is valid at all instruction locations: no. row[0]: 0: CFA=rbp+16 => rbp=[CFA-16] rsp=CFA+0 rip=[CFA-8] Arch default at entry point UnwindPlan: This UnwindPlan originally sourced from x86_64 at-func-entry default This UnwindPlan is sourced from the compiler: no. This UnwindPlan is valid at all instruction locations: not specified. row[0]: 0: CFA=rsp +8 => rsp=CFA+0 rip=[CFA-8] As you can see the eh_frame UnwindPlan is correct here. http://reviews.llvm.org/D21221 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
