| //===----- trampoline_setup.c - Implement __trampoline_setup -------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "int_lib.h" |
| |
| extern void __clear_cache(void *start, void *end); |
| |
| // The ppc compiler generates calls to __trampoline_setup() when creating |
| // trampoline functions on the stack for use with nested functions. |
| // This function creates a custom 40-byte trampoline function on the stack |
| // which loads r11 with a pointer to the outer function's locals |
| // and then jumps to the target nested function. |
| |
| #if __ppc__ && !defined(__powerpc64__) |
| COMPILER_RT_ABI void __trampoline_setup(uint32_t *trampOnStack, |
| int trampSizeAllocated, |
| const void *realFunc, void *localsPtr) { |
| // should never happen, but if compiler did not allocate |
| // enough space on stack for the trampoline, abort |
| if (trampSizeAllocated < 40) |
| compilerrt_abort(); |
| |
| // create trampoline |
| trampOnStack[0] = 0x7c0802a6; // mflr r0 |
| trampOnStack[1] = 0x4800000d; // bl Lbase |
| trampOnStack[2] = (uint32_t)realFunc; |
| trampOnStack[3] = (uint32_t)localsPtr; |
| trampOnStack[4] = 0x7d6802a6; // Lbase: mflr r11 |
| trampOnStack[5] = 0x818b0000; // lwz r12,0(r11) |
| trampOnStack[6] = 0x7c0803a6; // mtlr r0 |
| trampOnStack[7] = 0x7d8903a6; // mtctr r12 |
| trampOnStack[8] = 0x816b0004; // lwz r11,4(r11) |
| trampOnStack[9] = 0x4e800420; // bctr |
| |
| // clear instruction cache |
| __clear_cache(trampOnStack, &trampOnStack[10]); |
| } |
| #endif // __ppc__ && !defined(__powerpc64__) |
