runtime/arch/arm/jni_entrypoints_arm.S

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "asm_support_arm.S"

    /*
     * Jni dlsym lookup stub.
     */
    .extern artFindNativeMethod
ENTRY art_jni_dlsym_lookup_stub
    push   {r0, r1, r2, r3, lr}           @ spill regs
    .save  {r0, r1, r2, r3, lr}
    .pad #20
    .cfi_adjust_cfa_offset 20
    sub    sp, #12                        @ pad stack pointer to align frame
    .pad #12
    .cfi_adjust_cfa_offset 12
    blx    artFindNativeMethod
    mov    r12, r0                        @ save result in r12
    add    sp, #12                        @ restore stack pointer
    .cfi_adjust_cfa_offset -12
    pop    {r0, r1, r2, r3, lr}           @ restore regs
    .cfi_adjust_cfa_offset -20
    cmp    r12, #0                        @ is method code null?
    bxne   r12                            @ if non-null, tail call to method's code
    bx     lr                             @ otherwise, return to caller to handle exception
END art_jni_dlsym_lookup_stub

    /*
     * Entry point of native methods when JNI bug compatibility is enabled.
     */
    .extern artWorkAroundAppJniBugs
ENTRY art_work_around_app_jni_bugs
    @ save registers that may contain arguments and LR that will be crushed by a call
    push {r0-r3, lr}
    .save {r0-r3, lr}
    .cfi_adjust_cfa_offset 16
    .cfi_rel_offset r0, 0
    .cfi_rel_offset r1, 4
    .cfi_rel_offset r2, 8
    .cfi_rel_offset r3, 12
    sub sp, #12      @ 3 words of space for alignment
    mov r0, r9       @ pass Thread::Current
    mov r1, sp       @ pass SP
    bl  artWorkAroundAppJniBugs  @ (Thread*, SP)
    add sp, #12      @ rewind stack
    mov r12, r0      @ save target address
    pop {r0-r3, lr}  @ restore possibly modified argument registers
    .cfi_adjust_cfa_offset -16
    bx  r12          @ tail call into JNI routine
END art_work_around_app_jni_bugs