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Diffstat (limited to 'contrib/compiler-rt/lib/trampoline_setup.c')
-rw-r--r-- | contrib/compiler-rt/lib/trampoline_setup.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/trampoline_setup.c b/contrib/compiler-rt/lib/trampoline_setup.c new file mode 100644 index 0000000..a2f49a4 --- /dev/null +++ b/contrib/compiler-rt/lib/trampoline_setup.c @@ -0,0 +1,50 @@ +/* ===----- 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> + +#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__) +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__ */ |