| 1 | #; $ as -o test.o gas-cfi-test.s && gcc -nostdlib -o test test.o |
| 2 | |
| 3 | .text |
| 4 | |
| 5 | #; func_locvars |
| 6 | #; - function with a space on the stack |
| 7 | #; allocated for local variables |
| 8 | |
| 9 | .type func_locvars,@function |
| 10 | func_locvars: |
| 11 | .cfi_startproc |
| 12 | |
| 13 | #; alocate space for local vars |
| 14 | sub $0x1234,%rsp |
| 15 | .cfi_adjust_cfa_offset 0x1234 |
| 16 | |
| 17 | #; dummy body |
| 18 | movl $1,%eax |
| 19 | |
| 20 | #; release space of local vars and return |
| 21 | add $0x1234,%rsp |
| 22 | .cfi_adjust_cfa_offset -0x1234 |
| 23 | ret |
| 24 | .cfi_endproc |
| 25 | |
| 26 | #; func_prologue |
| 27 | #; - functions that begins with standard |
| 28 | #; prologue: "pushq %rbp; movq %rsp,%rbp" |
| 29 | |
| 30 | .type func_prologue,@function |
| 31 | func_prologue: |
| 32 | .cfi_startproc |
| 33 | |
| 34 | #; prologue, CFI is valid after |
| 35 | #; each instruction. |
| 36 | pushq %rbp |
| 37 | .cfi_def_cfa_offset 16 |
| 38 | .cfi_offset %rbp, -16 |
| 39 | movq %rsp, %rbp |
| 40 | .cfi_def_cfa_register %rbp |
| 41 | |
| 42 | #; function body |
| 43 | call func_locvars |
| 44 | addl $3, %eax |
| 45 | |
| 46 | #; epilogue with valid CFI |
| 47 | #; (we're better than gcc :-) |
| 48 | leaveq |
| 49 | .cfi_def_cfa %rsp, 8 |
| 50 | ret |
| 51 | .cfi_endproc |
| 52 | |
| 53 | #; func_otherreg |
| 54 | #; - function that moves frame pointer to |
| 55 | #; another register (r12) and then allocates |
| 56 | #; a space for local variables |
| 57 | |
| 58 | .type func_otherreg,@function |
| 59 | func_otherreg: |
| 60 | .cfi_startproc |
| 61 | |
| 62 | #; save frame pointer to r8 |
| 63 | movq %rsp,%r8 |
| 64 | .cfi_def_cfa_register r8 |
| 65 | |
| 66 | #; alocate space for local vars |
| 67 | #; (no .cfi_{def,adjust}_cfa_offset here, |
| 68 | #; because CFA is computed from r8!) |
| 69 | sub $100,%rsp |
| 70 | |
| 71 | #; function body |
| 72 | call func_prologue |
| 73 | addl $2, %eax |
| 74 | |
| 75 | #; restore frame pointer from r8 |
| 76 | movq %r8,%rsp |
| 77 | .cfi_def_cfa_register rsp |
| 78 | ret |
| 79 | .cfi_endproc |
| 80 | |
| 81 | #; main |
| 82 | #; - typical function |
| 83 | .type main,@function |
| 84 | main: |
| 85 | .cfi_startproc |
| 86 | |
| 87 | #; only function body that doesn't |
| 88 | #; touch the stack at all. |
| 89 | call func_otherreg |
| 90 | |
| 91 | #; return |
| 92 | ret |
| 93 | .cfi_endproc |
| 94 | |
| 95 | #; _start |
| 96 | #; - standard entry point |
| 97 | |
| 98 | .type _start,@function |
| 99 | .globl _start |
| 100 | _start: |
| 101 | .cfi_startproc |
| 102 | call main |
| 103 | movq %rax,%rdi |
| 104 | movq $0x3c,%rax |
| 105 | syscall |
| 106 | hlt |
| 107 | .cfi_endproc |
| 108 | |
| 109 | #; func_alldirectives |
| 110 | #; - test for all .cfi directives. |
| 111 | #; This function is never called and the CFI info doesn't make sense. |
| 112 | |
| 113 | .type func_alldirectives,@function |
| 114 | func_alldirectives: |
| 115 | .cfi_startproc simple |
| 116 | .cfi_def_cfa rsp,8 |
| 117 | nop |
| 118 | .cfi_def_cfa_offset 16 |
| 119 | nop |
| 120 | .cfi_def_cfa_register r8 |
| 121 | nop |
| 122 | .cfi_adjust_cfa_offset 0x1234 |
| 123 | nop |
| 124 | .cfi_offset %rsi, 0x10 |
| 125 | nop |
| 126 | .cfi_register %r8, %r9 |
| 127 | nop |
| 128 | .cfi_remember_state |
| 129 | nop |
| 130 | .cfi_restore %rbp |
| 131 | nop |
| 132 | .cfi_undefined %rip |
| 133 | nop |
| 134 | .cfi_same_value rbx |
| 135 | nop |
| 136 | .cfi_restore_state |
| 137 | ret |
| 138 | .cfi_endproc |