src/libcompiler_builtins/compiler-rt/lib/xray/xray_trampoline_arm.S

   1 #include "../builtins/assembly.h"
   2
   3     .syntax unified
   4     .arch armv6t2
   5     .fpu vfpv2
   6     .code 32
   7     .global _ZN6__xray19XRayPatchedFunctionE
   8
   9     @ Word-aligned function entry point
  10     .p2align 2
  11     @ Let C/C++ see the symbol
  12     .global __xray_FunctionEntry
  13     @ It preserves all registers except r0, r12(ip), r14(lr) and r15(pc)
  14     @ Assume that "q" part of the floating-point registers is not used
  15     @   for passing parameters to C/C++ functions.
  16     .type __xray_FunctionEntry, %function
  17     @ In C++ it is void extern "C" __xray_FunctionEntry(uint32_t FuncId) with
  18     @   FuncId passed in r0 register.
  19 __xray_FunctionEntry:
  20     PUSH {r1-r3,lr}
  21     @ Save floating-point parameters of the instrumented function
  22     VPUSH {d0-d7}
  23     MOVW r1,#:lower16:_ZN6__xray19XRayPatchedFunctionE
  24     MOVT r1,#:upper16:_ZN6__xray19XRayPatchedFunctionE
  25     LDR r2, [r1]
  26     @ Handler address is nullptr if handler is not set
  27     CMP r2, #0
  28     BEQ FunctionEntry_restore
  29     @ Function ID is already in r0 (the first parameter).
  30     @ r1=0 means that we are tracing an entry event
  31     MOV r1, #0
  32     @ Call the handler with 2 parameters in r0 and r1
  33     BLX r2
  34 FunctionEntry_restore:
  35     @ Restore floating-point parameters of the instrumented function
  36     VPOP {d0-d7}
  37     POP {r1-r3,pc}
  38
  39     @ Word-aligned function entry point
  40     .p2align 2
  41     @ Let C/C++ see the symbol
  42         .global __xray_FunctionExit
  43         @ Assume that d1-d7 are not used for the return value.
  44     @ Assume that "q" part of the floating-point registers is not used for the
  45     @   return value in C/C++.
  46         .type __xray_FunctionExit, %function
  47         @ In C++ it is extern "C" void __xray_FunctionExit(uint32_t FuncId) with
  48     @   FuncId passed in r0 register.
  49 __xray_FunctionExit:
  50     PUSH {r1-r3,lr}
  51     @ Save the floating-point return value of the instrumented function
  52     VPUSH {d0}
  53     @ Load the handler address
  54     MOVW r1,#:lower16:_ZN6__xray19XRayPatchedFunctionE
  55     MOVT r1,#:upper16:_ZN6__xray19XRayPatchedFunctionE
  56     LDR r2, [r1]
  57     @ Handler address is nullptr if handler is not set
  58     CMP r2, #0
  59     BEQ FunctionExit_restore
  60     @ Function ID is already in r0 (the first parameter).
  61     @ 1 means that we are tracing an exit event
  62     MOV r1, #1
  63     @ Call the handler with 2 parameters in r0 and r1
  64     BLX r2
  65 FunctionExit_restore:
  66     @ Restore the floating-point return value of the instrumented function
  67     VPOP {d0}
  68     POP {r1-r3,pc}
  69
  70     @ Word-aligned function entry point
  71     .p2align 2
  72     @ Let C/C++ see the symbol
  73     .global __xray_FunctionTailExit
  74     @ It preserves all registers except r0, r12(ip), r14(lr) and r15(pc)
  75     @ Assume that "q" part of the floating-point registers is not used
  76     @   for passing parameters to C/C++ functions.
  77     .type __xray_FunctionTailExit, %function
  78     @ In C++ it is void extern "C" __xray_FunctionTailExit(uint32_t FuncId)
  79     @   with FuncId passed in r0 register.
  80 __xray_FunctionTailExit:
  81     PUSH {r1-r3,lr}
  82     @ Save floating-point parameters of the instrumented function
  83     VPUSH {d0-d7}
  84     MOVW r1,#:lower16:_ZN6__xray19XRayPatchedFunctionE
  85     MOVT r1,#:upper16:_ZN6__xray19XRayPatchedFunctionE
  86     LDR r2, [r1]
  87     @ Handler address is nullptr if handler is not set
  88     CMP r2, #0
  89     BEQ FunctionTailExit_restore
  90     @ Function ID is already in r0 (the first parameter).
  91     @ r1=2 means that we are tracing a tail exit event
  92     @ But before the logging part of XRay is ready, we pretend that here a
  93     @   normal function exit happens, so we give the handler code 1
  94     MOV r1, #1
  95     @ Call the handler with 2 parameters in r0 and r1
  96     BLX r2
  97 FunctionTailExit_restore:
  98     @ Restore floating-point parameters of the instrumented function
  99     VPOP {d0-d7}
 100     POP {r1-r3,pc}
 101
 102 NO_EXEC_STACK_DIRECTIVE