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/* ===----- trampoline_setup.c - Implement __trampoline_setup -------------===
*
* The LLVM Compiler Infrastructure
*
* This file is dual licensed under the MIT and the University of Illinois Open
* Source Licenses. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*/
#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__
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__ */
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