jit/JITStubsARM.h

   1 /*
   2  * Copyright (C) 2008, 2009, 2013 Apple Inc. All rights reserved.
   3  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
   4  * Copyright (C) Research In Motion Limited 2010, 2011. All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1.  Redistributions of source code must retain the above copyright
  11  *     notice, this list of conditions and the following disclaimer.
  12  * 2.  Redistributions in binary form must reproduce the above copyright
  13  *     notice, this list of conditions and the following disclaimer in the
  14  *     documentation and/or other materials provided with the distribution.
  15  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  16  *     its contributors may be used to endorse or promote products derived
  17  *     from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  20  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  22  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  23  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  24  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  26  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef JITStubsARM_h
  32 #define JITStubsARM_h
  33
  34 #if !CPU(ARM_TRADITIONAL)
  35 #error "JITStubsARM.h should only be #included if CPU(ARM_TRADITIONAL)"
  36 #endif
  37
  38 #if !USE(JSVALUE32_64)
  39 #error "JITStubsARM.h only implements USE(JSVALUE32_64)"
  40 #endif
  41
  42 namespace JSC {
  43
  44 #if COMPILER(GCC)
  45
  46 #if USE(MASM_PROBE)
  47 // The following are offsets for MacroAssembler::ProbeContext fields accessed
  48 // by the ctiMasmProbeTrampoline stub.
  49
  50 #define PTR_SIZE 4
  51 #define PROBE_PROBE_FUNCTION_OFFSET (0 * PTR_SIZE)
  52 #define PROBE_ARG1_OFFSET (1 * PTR_SIZE)
  53 #define PROBE_ARG2_OFFSET (2 * PTR_SIZE)
  54
  55 #define PROBE_FIRST_GPREG_OFFSET (4 * PTR_SIZE)
  56
  57 #define GPREG_SIZE 4
  58 #define PROBE_CPU_R0_OFFSET (PROBE_FIRST_GPREG_OFFSET + (0 * GPREG_SIZE))
  59 #define PROBE_CPU_R1_OFFSET (PROBE_FIRST_GPREG_OFFSET + (1 * GPREG_SIZE))
  60 #define PROBE_CPU_R2_OFFSET (PROBE_FIRST_GPREG_OFFSET + (2 * GPREG_SIZE))
  61 #define PROBE_CPU_R3_OFFSET (PROBE_FIRST_GPREG_OFFSET + (3 * GPREG_SIZE))
  62 #define PROBE_CPU_R4_OFFSET (PROBE_FIRST_GPREG_OFFSET + (4 * GPREG_SIZE))
  63 #define PROBE_CPU_R5_OFFSET (PROBE_FIRST_GPREG_OFFSET + (5 * GPREG_SIZE))
  64 #define PROBE_CPU_R6_OFFSET (PROBE_FIRST_GPREG_OFFSET + (6 * GPREG_SIZE))
  65 #define PROBE_CPU_R7_OFFSET (PROBE_FIRST_GPREG_OFFSET + (7 * GPREG_SIZE))
  66 #define PROBE_CPU_R8_OFFSET (PROBE_FIRST_GPREG_OFFSET + (8 * GPREG_SIZE))
  67 #define PROBE_CPU_R9_OFFSET (PROBE_FIRST_GPREG_OFFSET + (9 * GPREG_SIZE))
  68 #define PROBE_CPU_R10_OFFSET (PROBE_FIRST_GPREG_OFFSET + (10 * GPREG_SIZE))
  69 #define PROBE_CPU_R11_OFFSET (PROBE_FIRST_GPREG_OFFSET + (11 * GPREG_SIZE))
  70 #define PROBE_CPU_IP_OFFSET (PROBE_FIRST_GPREG_OFFSET + (12 * GPREG_SIZE))
  71 #define PROBE_CPU_SP_OFFSET (PROBE_FIRST_GPREG_OFFSET + (13 * GPREG_SIZE))
  72 #define PROBE_CPU_LR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (14 * GPREG_SIZE))
  73 #define PROBE_CPU_PC_OFFSET (PROBE_FIRST_GPREG_OFFSET + (15 * GPREG_SIZE))
  74
  75 #define PROBE_CPU_APSR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (16 * GPREG_SIZE))
  76 #define PROBE_CPU_FPSCR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (17 * GPREG_SIZE))
  77
  78 #define PROBE_FIRST_FPREG_OFFSET (PROBE_FIRST_GPREG_OFFSET + (18 * GPREG_SIZE))
  79
  80 #define FPREG_SIZE 8
  81 #define PROBE_CPU_D0_OFFSET (PROBE_FIRST_FPREG_OFFSET + (0 * FPREG_SIZE))
  82 #define PROBE_CPU_D1_OFFSET (PROBE_FIRST_FPREG_OFFSET + (1 * FPREG_SIZE))
  83 #define PROBE_CPU_D2_OFFSET (PROBE_FIRST_FPREG_OFFSET + (2 * FPREG_SIZE))
  84 #define PROBE_CPU_D3_OFFSET (PROBE_FIRST_FPREG_OFFSET + (3 * FPREG_SIZE))
  85 #define PROBE_CPU_D4_OFFSET (PROBE_FIRST_FPREG_OFFSET + (4 * FPREG_SIZE))
  86 #define PROBE_CPU_D5_OFFSET (PROBE_FIRST_FPREG_OFFSET + (5 * FPREG_SIZE))
  87 #define PROBE_CPU_D6_OFFSET (PROBE_FIRST_FPREG_OFFSET + (6 * FPREG_SIZE))
  88 #define PROBE_CPU_D7_OFFSET (PROBE_FIRST_FPREG_OFFSET + (7 * FPREG_SIZE))
  89 #define PROBE_CPU_D8_OFFSET (PROBE_FIRST_FPREG_OFFSET + (8 * FPREG_SIZE))
  90 #define PROBE_CPU_D9_OFFSET (PROBE_FIRST_FPREG_OFFSET + (9 * FPREG_SIZE))
  91 #define PROBE_CPU_D10_OFFSET (PROBE_FIRST_FPREG_OFFSET + (10 * FPREG_SIZE))
  92 #define PROBE_CPU_D11_OFFSET (PROBE_FIRST_FPREG_OFFSET + (11 * FPREG_SIZE))
  93 #define PROBE_CPU_D12_OFFSET (PROBE_FIRST_FPREG_OFFSET + (12 * FPREG_SIZE))
  94 #define PROBE_CPU_D13_OFFSET (PROBE_FIRST_FPREG_OFFSET + (13 * FPREG_SIZE))
  95 #define PROBE_CPU_D14_OFFSET (PROBE_FIRST_FPREG_OFFSET + (14 * FPREG_SIZE))
  96 #define PROBE_CPU_D15_OFFSET (PROBE_FIRST_FPREG_OFFSET + (15 * FPREG_SIZE))
  97
  98 #define PROBE_SIZE (PROBE_FIRST_FPREG_OFFSET + (16 * FPREG_SIZE))
  99
 100 // These ASSERTs remind you that if you change the layout of ProbeContext,
 101 // you need to change ctiMasmProbeTrampoline offsets above to match.
 102 #define PROBE_OFFSETOF(x) offsetof(struct MacroAssembler::ProbeContext, x)
 103 COMPILE_ASSERT(PROBE_OFFSETOF(probeFunction) == PROBE_PROBE_FUNCTION_OFFSET, ProbeContext_probeFunction_offset_matches_ctiMasmProbeTrampoline);
 104 COMPILE_ASSERT(PROBE_OFFSETOF(arg1) == PROBE_ARG1_OFFSET, ProbeContext_arg1_offset_matches_ctiMasmProbeTrampoline);
 105 COMPILE_ASSERT(PROBE_OFFSETOF(arg2) == PROBE_ARG2_OFFSET, ProbeContext_arg2_offset_matches_ctiMasmProbeTrampoline);
 106
 107 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r0) == PROBE_CPU_R0_OFFSET, ProbeContext_cpu_r0_offset_matches_ctiMasmProbeTrampoline);
 108 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r1) == PROBE_CPU_R1_OFFSET, ProbeContext_cpu_r1_offset_matches_ctiMasmProbeTrampoline);
 109 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r2) == PROBE_CPU_R2_OFFSET, ProbeContext_cpu_r2_offset_matches_ctiMasmProbeTrampoline);
 110 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r3) == PROBE_CPU_R3_OFFSET, ProbeContext_cpu_r3_offset_matches_ctiMasmProbeTrampoline);
 111 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r4) == PROBE_CPU_R4_OFFSET, ProbeContext_cpu_r4_offset_matches_ctiMasmProbeTrampoline);
 112 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r5) == PROBE_CPU_R5_OFFSET, ProbeContext_cpu_r5_offset_matches_ctiMasmProbeTrampoline);
 113 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r6) == PROBE_CPU_R6_OFFSET, ProbeContext_cpu_r6_offset_matches_ctiMasmProbeTrampoline);
 114 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r7) == PROBE_CPU_R7_OFFSET, ProbeContext_cpu_r70_offset_matches_ctiMasmProbeTrampoline);
 115 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r8) == PROBE_CPU_R8_OFFSET, ProbeContext_cpu_r8_offset_matches_ctiMasmProbeTrampoline);
 116 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r9) == PROBE_CPU_R9_OFFSET, ProbeContext_cpu_r9_offset_matches_ctiMasmProbeTrampoline);
 117 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r10) == PROBE_CPU_R10_OFFSET, ProbeContext_cpu_r10_offset_matches_ctiMasmProbeTrampoline);
 118 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r11) == PROBE_CPU_R11_OFFSET, ProbeContext_cpu_r11_offset_matches_ctiMasmProbeTrampoline);
 119 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.ip) == PROBE_CPU_IP_OFFSET, ProbeContext_cpu_ip_offset_matches_ctiMasmProbeTrampoline);
 120 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.sp) == PROBE_CPU_SP_OFFSET, ProbeContext_cpu_sp_offset_matches_ctiMasmProbeTrampoline);
 121 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.lr) == PROBE_CPU_LR_OFFSET, ProbeContext_cpu_lr_offset_matches_ctiMasmProbeTrampoline);
 122 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.pc) == PROBE_CPU_PC_OFFSET, ProbeContext_cpu_pc_offset_matches_ctiMasmProbeTrampoline);
 123
 124 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.apsr) == PROBE_CPU_APSR_OFFSET, ProbeContext_cpu_apsr_offset_matches_ctiMasmProbeTrampoline);
 125 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.fpscr) == PROBE_CPU_FPSCR_OFFSET, ProbeContext_cpu_fpscr_offset_matches_ctiMasmProbeTrampoline);
 126
 127 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d0) == PROBE_CPU_D0_OFFSET, ProbeContext_cpu_d0_offset_matches_ctiMasmProbeTrampoline);
 128 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d1) == PROBE_CPU_D1_OFFSET, ProbeContext_cpu_d1_offset_matches_ctiMasmProbeTrampoline);
 129 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d2) == PROBE_CPU_D2_OFFSET, ProbeContext_cpu_d2_offset_matches_ctiMasmProbeTrampoline);
 130 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d3) == PROBE_CPU_D3_OFFSET, ProbeContext_cpu_d3_offset_matches_ctiMasmProbeTrampoline);
 131 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d4) == PROBE_CPU_D4_OFFSET, ProbeContext_cpu_d4_offset_matches_ctiMasmProbeTrampoline);
 132 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d5) == PROBE_CPU_D5_OFFSET, ProbeContext_cpu_d5_offset_matches_ctiMasmProbeTrampoline);
 133 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d6) == PROBE_CPU_D6_OFFSET, ProbeContext_cpu_d6_offset_matches_ctiMasmProbeTrampoline);
 134 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d7) == PROBE_CPU_D7_OFFSET, ProbeContext_cpu_d7_offset_matches_ctiMasmProbeTrampoline);
 135 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d8) == PROBE_CPU_D8_OFFSET, ProbeContext_cpu_d8_offset_matches_ctiMasmProbeTrampoline);
 136 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d9) == PROBE_CPU_D9_OFFSET, ProbeContext_cpu_d9_offset_matches_ctiMasmProbeTrampoline);
 137 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d10) == PROBE_CPU_D10_OFFSET, ProbeContext_cpu_d10_offset_matches_ctiMasmProbeTrampoline);
 138 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d11) == PROBE_CPU_D11_OFFSET, ProbeContext_cpu_d11_offset_matches_ctiMasmProbeTrampoline);
 139 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d12) == PROBE_CPU_D12_OFFSET, ProbeContext_cpu_d12_offset_matches_ctiMasmProbeTrampoline);
 140 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d13) == PROBE_CPU_D13_OFFSET, ProbeContext_cpu_d13_offset_matches_ctiMasmProbeTrampoline);
 141 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d14) == PROBE_CPU_D14_OFFSET, ProbeContext_cpu_d14_offset_matches_ctiMasmProbeTrampoline);
 142 COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d15) == PROBE_CPU_D15_OFFSET, ProbeContext_cpu_d15_offset_matches_ctiMasmProbeTrampoline);
 143 COMPILE_ASSERT(sizeof(MacroAssembler::ProbeContext) == PROBE_SIZE, ProbeContext_size_matches_ctiMasmProbeTrampoline);
 144 #undef PROBE_OFFSETOF
 145
 146 #endif // USE(MASM_PROBE)
 147
 148
 149 #if USE(MASM_PROBE)
 150 asm (
 151 ".text" "\n"
 152 ".globl " SYMBOL_STRING(ctiMasmProbeTrampoline) "\n"
 153 HIDE_SYMBOL(ctiMasmProbeTrampoline) "\n"
 154 INLINE_ARM_FUNCTION(ctiMasmProbeTrampoline) "\n"
 155 SYMBOL_STRING(ctiMasmProbeTrampoline) ":" "\n"
 156
 157     // MacroAssembler::probe() has already generated code to store some values.
 158     // The top of stack now looks like this:
 159     //     esp[0 * ptrSize]: probeFunction
 160     //     esp[1 * ptrSize]: arg1
 161     //     esp[2 * ptrSize]: arg2
 162     //     esp[3 * ptrSize]: saved r3 / S0
 163     //     esp[4 * ptrSize]: saved ip
 164     //     esp[5 * ptrSize]: saved lr
 165     //     esp[6 * ptrSize]: saved sp
 166
 167     "mov       ip, sp" "\n"
 168     "mov       r3, sp" "\n"
 169     "sub       r3, r3, #" STRINGIZE_VALUE_OF(PROBE_SIZE) "\n"
 170
 171     // The ARM EABI specifies that the stack needs to be 16 byte aligned.
 172     "bic       r3, r3, #0xf" "\n"
 173     "mov       sp, r3" "\n"
 174
 175     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
 176     "add       lr, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R0_OFFSET) "\n"
 177     "stmia     lr, { r0-r11 }" "\n"
 178     "mrs       lr, APSR" "\n"
 179     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
 180     "vmrs      lr, FPSCR" "\n"
 181     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_FPSCR_OFFSET) "]" "\n"
 182
 183     "ldr       lr, [ip, #0 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 184     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "]" "\n"
 185     "ldr       lr, [ip, #1 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 186     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_ARG1_OFFSET) "]" "\n"
 187     "ldr       lr, [ip, #2 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 188     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_ARG2_OFFSET) "]" "\n"
 189     "ldr       lr, [ip, #3 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 190     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R3_OFFSET) "]" "\n"
 191     "ldr       lr, [ip, #4 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 192     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
 193     "ldr       lr, [ip, #5 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 194     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
 195     "ldr       lr, [ip, #6 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
 196     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 197
 198     "ldr       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
 199
 200     "add       ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_D0_OFFSET) "\n"
 201     "vstmia.64 ip, { d0-d15 }" "\n"
 202
 203     "mov       fp, sp" "\n" // Save the ProbeContext*.
 204
 205     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "]" "\n"
 206     "mov       r0, sp" "\n" // the ProbeContext* arg.
 207     "blx       ip" "\n"
 208
 209     "mov       sp, fp" "\n"
 210
 211     // To enable probes to modify register state, we copy all registers
 212     // out of the ProbeContext before returning.
 213
 214     "add       ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_D15_OFFSET + FPREG_SIZE) "\n"
 215     "vldmdb.64 ip!, { d0-d15 }" "\n"
 216     "add       ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R11_OFFSET + GPREG_SIZE) "\n"
 217     "ldmdb     ip, { r0-r11 }" "\n"
 218     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_FPSCR_OFFSET) "]" "\n"
 219     "vmsr      FPSCR, ip" "\n"
 220
 221     // There are 5 more registers left to restore: ip, sp, lr, pc, and apsr.
 222     // There are 2 issues that complicate the restoration of these last few
 223     // registers:
 224     //
 225     // 1. Normal ARM calling convention relies on moving lr to pc to return to
 226     //    the caller. In our case, the address to return to is specified by
 227     //    ProbeContext.cpu.pc. And at that moment, we won't have any available
 228     //    scratch registers to hold the return address (lr needs to hold
 229     //    ProbeContext.cpu.lr, not the return address).
 230     //
 231     //    The solution is to store the return address on the stack and load the
 232     //     pc from there.
 233     //
 234     // 2. Issue 1 means we will need to write to the stack location at
 235     //    ProbeContext.cpu.sp - 4. But if the user probe function had  modified
 236     //    the value of ProbeContext.cpu.sp to point in the range between
 237     //    &ProbeContext.cpu.ip thru &ProbeContext.cpu.aspr, then the action for
 238     //    Issue 1 may trash the values to be restored before we can restore
 239     //    them.
 240     //
 241     //    The solution is to check if ProbeContext.cpu.sp contains a value in
 242     //    the undesirable range. If so, we copy the remaining ProbeContext
 243     //    register data to a safe range (at memory lower than where
 244     //    ProbeContext.cpu.sp points) first, and restore the remaining register
 245     //    from this new range.
 246
 247     "add       ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "\n"
 248     "ldr       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 249     "cmp       lr, ip" "\n"
 250     "bgt     " SYMBOL_STRING(ctiMasmProbeTrampolineEnd) "\n"
 251
 252     // We get here because the new expected stack pointer location is lower
 253     // than where it's supposed to be. This means the safe range of stack
 254     // memory where we'll be copying the remaining register restore values to
 255     // might be in a region of memory below the sp i.e. unallocated stack
 256     // memory. This in turn makes it vulnerable to interrupts potentially
 257     // trashing the copied values. To prevent that, we must first allocate the
 258     // needed stack memory by adjusting the sp before the copying.
 259
 260     "sub       lr, lr, #(6 * " STRINGIZE_VALUE_OF(PTR_SIZE)
 261                          " + " STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) ")" "\n"
 262
 263     "mov       ip, sp" "\n"
 264     "mov       sp, lr" "\n"
 265     "mov       lr, ip" "\n"
 266
 267     "ldr       ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
 268     "str       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
 269     "ldr       ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 270     "str       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 271     "ldr       ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
 272     "str       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
 273     "ldr       ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
 274     "str       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
 275     "ldr       ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
 276     "str       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
 277
 278 SYMBOL_STRING(ctiMasmProbeTrampolineEnd) ":" "\n"
 279     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
 280     "ldr       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 281     "sub       lr, lr, #" STRINGIZE_VALUE_OF(PTR_SIZE) "\n"
 282     "str       ip, [lr]" "\n"
 283     "str       lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 284
 285     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
 286     "msr       APSR, ip" "\n"
 287     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
 288     "mov       lr, ip" "\n"
 289     "ldr       ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
 290     "ldr       sp, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
 291
 292     "pop       { pc }" "\n"
 293 );
 294 #endif // USE(MASM_PROBE)
 295
 296
 297
 298 #endif // COMPILER(GCC)
 299
 300 } // namespace JSC
 301
 302 #endif // JITStubsARM_h