1 /* ===----- trampoline_setup.c - Implement __trampoline_setup -------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is distributed under the University of Illinois Open Source 6 * License. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 */ 10 11 #include <stdint.h> 12 #include <stdlib.h> 13 14 extern void __clear_cache(void* start, void* end); 15 16 /* 17 * The ppc compiler generates calls to __trampoline_setup() when creating 18 * trampoline functions on the stack for use with nested functions. 19 * This function creates a custom 40-byte trampoline function on the stack 20 * which loads r11 with a pointer to the outer function's locals 21 * and then jumps to the target nested function. 22 */ 23 24 #if __ppc__ 25 void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 26 const void* realFunc, void* localsPtr) 27 { 28 /* should never happen, but if compiler did not allocate */ 29 /* enough space on stack for the trampoline, abort */ 30 if ( trampSizeAllocated < 40 ) 31 abort(); 32 33 /* create trampoline */ 34 trampOnStack[0] = 0x7c0802a6; /* mflr r0 */ 35 trampOnStack[1] = 0x4800000d; /* bl Lbase */ 36 trampOnStack[2] = (uint32_t)realFunc; 37 trampOnStack[3] = (uint32_t)localsPtr; 38 trampOnStack[4] = 0x7d6802a6; /* Lbase: mflr r11 */ 39 trampOnStack[5] = 0x818b0000; /* lwz r12,0(r11) */ 40 trampOnStack[6] = 0x7c0803a6; /* mtlr r0 */ 41 trampOnStack[7] = 0x7d8903a6; /* mtctr r12 */ 42 trampOnStack[8] = 0x816b0004; /* lwz r11,4(r11) */ 43 trampOnStack[9] = 0x4e800420; /* bctr */ 44 45 /* clear instruction cache */ 46 __clear_cache(trampOnStack, &trampOnStack[10]); 47 } 48 #endif /* __ppc__ */ 49
