diff options
Diffstat (limited to 'lib/xray/xray_trampoline_arm.S')
| -rw-r--r-- | lib/xray/xray_trampoline_arm.S | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/lib/xray/xray_trampoline_arm.S b/lib/xray/xray_trampoline_arm.S index 5d87c971364dd..71dbee65d8250 100644 --- a/lib/xray/xray_trampoline_arm.S +++ b/lib/xray/xray_trampoline_arm.S @@ -1,8 +1,11 @@ +#include "../builtins/assembly.h" + .syntax unified .arch armv6t2 .fpu vfpv2 .code 32 .global _ZN6__xray19XRayPatchedFunctionE + @ Word-aligned function entry point .p2align 2 @ Let C/C++ see the symbol @@ -63,3 +66,37 @@ FunctionExit_restore: @ Restore the floating-point return value of the instrumented function VPOP {d0} POP {r1-r3,pc} + + @ Word-aligned function entry point + .p2align 2 + @ Let C/C++ see the symbol + .global __xray_FunctionTailExit + @ It preserves all registers except r0, r12(ip), r14(lr) and r15(pc) + @ Assume that "q" part of the floating-point registers is not used + @ for passing parameters to C/C++ functions. + .type __xray_FunctionTailExit, %function + @ In C++ it is void extern "C" __xray_FunctionTailExit(uint32_t FuncId) + @ with FuncId passed in r0 register. +__xray_FunctionTailExit: + PUSH {r1-r3,lr} + @ Save floating-point parameters of the instrumented function + VPUSH {d0-d7} + MOVW r1,#:lower16:_ZN6__xray19XRayPatchedFunctionE + MOVT r1,#:upper16:_ZN6__xray19XRayPatchedFunctionE + LDR r2, [r1] + @ Handler address is nullptr if handler is not set + CMP r2, #0 + BEQ FunctionTailExit_restore + @ Function ID is already in r0 (the first parameter). + @ r1=2 means that we are tracing a tail exit event + @ But before the logging part of XRay is ready, we pretend that here a + @ normal function exit happens, so we give the handler code 1 + MOV r1, #1 + @ Call the handler with 2 parameters in r0 and r1 + BLX r2 +FunctionTailExit_restore: + @ Restore floating-point parameters of the instrumented function + VPOP {d0-d7} + POP {r1-r3,pc} + +NO_EXEC_STACK_DIRECTIVE |