| //===----- trampoline_setup.c - Implement __trampoline_setup -------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include <stdint.h> |
| #include <stdlib.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__ |
| 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 ) |
| 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__ |