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1//===----- trampoline_setup.c - Implement __trampoline_setup -------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "int_lib.h"10 11extern void __clear_cache(void *start, void *end);12 13// The ppc compiler generates calls to __trampoline_setup() when creating14// trampoline functions on the stack for use with nested functions.15// This function creates a custom 40-byte trampoline function on the stack16// which loads r11 with a pointer to the outer function's locals17// and then jumps to the target nested function.18 19#if __powerpc__ && !defined(__powerpc64__)20COMPILER_RT_ABI void __trampoline_setup(uint32_t *trampOnStack,21 int trampSizeAllocated,22 const void *realFunc, void *localsPtr) {23 // should never happen, but if compiler did not allocate24 // enough space on stack for the trampoline, abort25 if (trampSizeAllocated < 40)26 compilerrt_abort();27 28 // create trampoline29 trampOnStack[0] = 0x7c0802a6; // mflr r030 trampOnStack[1] = 0x4800000d; // bl Lbase31 trampOnStack[2] = (uint32_t)realFunc;32 trampOnStack[3] = (uint32_t)localsPtr;33 trampOnStack[4] = 0x7d6802a6; // Lbase: mflr r1134 trampOnStack[5] = 0x818b0000; // lwz r12,0(r11)35 trampOnStack[6] = 0x7c0803a6; // mtlr r036 trampOnStack[7] = 0x7d8903a6; // mtctr r1237 trampOnStack[8] = 0x816b0004; // lwz r11,4(r11)38 trampOnStack[9] = 0x4e800420; // bctr39 40 // clear instruction cache41 __clear_cache(trampOnStack, &trampOnStack[10]);42}43#endif // __powerpc__ && !defined(__powerpc64__)44