How can I truncate the mangled C++ identifiers shown by GDB's disassemble command?

Question

GDB's disassemble command is nice for short C identifiers, e.g. main. For long, mangled C++ identifiers the verbosity is overkill. For example, using icpc I see results like

(gdb) disassemble 0x49de2f 0x49de5b
Dump of assembler code from 0x49de2f to 0x49de5b:
0x000000000049de2f <_ZN5pecos8suzerain16fftw_multi_array6detail18c2c_buffer_processIPA2_dPKSt7complexIdEilNS2_26complex_copy_differentiateIS4_EEEEvT_T1_T2_T0_SD_SE_RKT3_+167>: mov    0x18(%rsp),%rsi

Displays that long are annoying in the CLI. They make GDB's TUI assembly display all but useless.

Is there a way to tell GDB to show a truncated identifier? Say clip all but 50 characters?

Answer 1

Current GDB from CVS behaves the way you want when it knows that there is only one function in the disassembly:

(gdb) disas 0x000000000040071c
Dump of assembler code for function _ZNKSt8_Rb_treeIPiSt4pairIKS0_S0_ESt10_Select1stIS3_ESt4lessIS0_ESaIS3_EE21_M_get_Node_allocatorEv:
   0x000000000040071c <+0>: push   %rbp
   0x000000000040071d <+1>: mov    %rsp,%rbp
   0x0000000000400720 <+4>: mov    %rdi,-0x8(%rbp)
   0x0000000000400724 <+8>: mov    -0x8(%rbp),%rax
   0x0000000000400728 <+12>:    leaveq 
   0x0000000000400729 <+13>:    retq   
End of assembler dump.

When GDB can't know whether or not disassembly will cross function boundary, it still prints the "long" form:

(gdb) disas 0x000000000040071c 0x000000000040071c+1
Dump of assembler code from 0x40071c to 0x40071d:
   0x000000000040071c <_ZNKSt8_Rb_treeIPiSt4pairIKS0_S0_ESt10_Select1stIS3_ESt4lessIS0_ESaIS3_EE21_M_get_Node_allocatorEv+0>:   push   %rbp
End of assembler dump.

Here is the patch which introduced the "short form".

Answer 2

This doesn't really answer your question, but you might be able to at least demangle things to make them a little less ugly:

set print asm-demangle on