trampoline_setup.c revision 276789
1276789Sdim/* ===----- trampoline_setup.c - Implement __trampoline_setup -------------=== 2276789Sdim * 3276789Sdim * The LLVM Compiler Infrastructure 4276789Sdim * 5276789Sdim * This file is dual licensed under the MIT and the University of Illinois Open 6276789Sdim * Source Licenses. See LICENSE.TXT for details. 7276789Sdim * 8276789Sdim * ===----------------------------------------------------------------------=== 9276789Sdim */ 10276789Sdim 11276789Sdim#include "int_lib.h" 12276789Sdim 13276789Sdimextern void __clear_cache(void* start, void* end); 14276789Sdim 15276789Sdim/* 16276789Sdim * The ppc compiler generates calls to __trampoline_setup() when creating 17276789Sdim * trampoline functions on the stack for use with nested functions. 18276789Sdim * This function creates a custom 40-byte trampoline function on the stack 19276789Sdim * which loads r11 with a pointer to the outer function's locals 20276789Sdim * and then jumps to the target nested function. 21276789Sdim */ 22276789Sdim 23276789Sdim#if __ppc__ && !defined(__powerpc64__) 24276789SdimCOMPILER_RT_ABI void 25276789Sdim__trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 26276789Sdim const void* realFunc, void* localsPtr) 27276789Sdim{ 28276789Sdim /* should never happen, but if compiler did not allocate */ 29276789Sdim /* enough space on stack for the trampoline, abort */ 30276789Sdim if ( trampSizeAllocated < 40 ) 31276789Sdim compilerrt_abort(); 32276789Sdim 33276789Sdim /* create trampoline */ 34276789Sdim trampOnStack[0] = 0x7c0802a6; /* mflr r0 */ 35276789Sdim trampOnStack[1] = 0x4800000d; /* bl Lbase */ 36276789Sdim trampOnStack[2] = (uint32_t)realFunc; 37276789Sdim trampOnStack[3] = (uint32_t)localsPtr; 38276789Sdim trampOnStack[4] = 0x7d6802a6; /* Lbase: mflr r11 */ 39276789Sdim trampOnStack[5] = 0x818b0000; /* lwz r12,0(r11) */ 40276789Sdim trampOnStack[6] = 0x7c0803a6; /* mtlr r0 */ 41276789Sdim trampOnStack[7] = 0x7d8903a6; /* mtctr r12 */ 42276789Sdim trampOnStack[8] = 0x816b0004; /* lwz r11,4(r11) */ 43276789Sdim trampOnStack[9] = 0x4e800420; /* bctr */ 44276789Sdim 45276789Sdim /* clear instruction cache */ 46276789Sdim __clear_cache(trampOnStack, &trampOnStack[10]); 47276789Sdim} 48276789Sdim#endif /* __ppc__ && !defined(__powerpc64__) */ 49