sysdeps/x86_64/_mcount.S

   1 /* Machine-specific calling sequence for `mcount' profiling function.  x86-64 version.
   2    Copyright (C) 2002-2014 Free Software Foundation, Inc.
   3    Contributed by Andreas Jaeger <aj@suse.de>.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 /* Assembly stub to invoke _mcount().  Compiler generated code calls
  21    this stub after executing a function's prologue and without saving any
  22    registers.  It is therefore necessary to preserve %rcx, %rdx, %rsi, %rdi,
  23    %r8, %r9 as they may contain function arguments.  */
  24
  25 #include <sysdep.h>
  26
  27         .globl C_SYMBOL_NAME(_mcount)
  28         .type C_SYMBOL_NAME(_mcount), @function
  29         .align ALIGNARG(4)
  30 C_LABEL(_mcount)
  31         /* Allocate space for 7 registers.  */
  32         subq    $56,%rsp
  33         movq    %rax,(%rsp)
  34         movq    %rcx,8(%rsp)
  35         movq    %rdx,16(%rsp)
  36         movq    %rsi,24(%rsp)
  37         movq    %rdi,32(%rsp)
  38         movq    %r8,40(%rsp)
  39         movq    %r9,48(%rsp)
  40
  41         /* Setup parameter for __mcount_internal.  */
  42         /* selfpc is the return address on the stack.  */
  43         movq    56(%rsp),%rsi
  44         /* Get frompc via the frame pointer.  */
  45         movq    8(%rbp),%rdi
  46 #ifdef PIC
  47         call C_SYMBOL_NAME(__mcount_internal)@PLT
  48 #else
  49         call C_SYMBOL_NAME(__mcount_internal)
  50 #endif
  51         /* Pop the saved registers.  Please note that `mcount' has no
  52            return value.  */
  53         movq    48(%rsp),%r9
  54         movq    40(%rsp),%r8
  55         movq    32(%rsp),%rdi
  56         movq    24(%rsp),%rsi
  57         movq    16(%rsp),%rdx
  58         movq    8(%rsp),%rcx
  59         movq    (%rsp),%rax
  60         addq    $56,%rsp
  61         ret
  62
  63         ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount))
  64
  65 #undef mcount
  66 weak_alias (_mcount, mcount)
  67
  68         .globl C_SYMBOL_NAME(__fentry__)
  69         .type C_SYMBOL_NAME(__fentry__), @function
  70         .align ALIGNARG(4)
  71 C_LABEL(__fentry__)
  72         /* Allocate space for 7 registers.  */
  73         subq    $64,%rsp
  74         movq    %rax,(%rsp)
  75         movq    %rcx,8(%rsp)
  76         movq    %rdx,16(%rsp)
  77         movq    %rsi,24(%rsp)
  78         movq    %rdi,32(%rsp)
  79         movq    %r8,40(%rsp)
  80         movq    %r9,48(%rsp)
  81
  82         /* Setup parameter for __mcount_internal.  */
  83         /* selfpc is the return address on the stack.  */
  84         movq    64(%rsp),%rsi
  85         /* caller is the return address above it */
  86         movq    72(%rsp),%rdi
  87 #ifdef PIC
  88         call C_SYMBOL_NAME(__mcount_internal)@PLT
  89 #else
  90         call C_SYMBOL_NAME(__mcount_internal)
  91 #endif
  92         /* Pop the saved registers.  Please note that `__fentry__' has no
  93            return value.  */
  94         movq    48(%rsp),%r9
  95         movq    40(%rsp),%r8
  96         movq    32(%rsp),%rdi
  97         movq    24(%rsp),%rsi
  98         movq    16(%rsp),%rdx
  99         movq    8(%rsp),%rcx
 100         movq    (%rsp),%rax
 101         addq    $64,%rsp
 102         ret
 103
 104         ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(__fentry__))