Initial import of compiler-rt.
-
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@74292 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/trampoline_setup.c b/lib/trampoline_setup.c
new file mode 100644
index 0000000..a8906bc
--- /dev/null
+++ b/lib/trampoline_setup.c
@@ -0,0 +1,46 @@
+//===----- 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__