+
+//===----------------------------------------------------------------------===//
+// Callee-saved register lists.
+//===----------------------------------------------------------------------===//
+
+def CSR_NoRegs : CalleeSavedRegs<(add)>;
+
+def CSR_AAPCS : CalleeSavedRegs<(add LR, R11, R10, R9, R8, R7, R6, R5, R4,
+ (sequence "D%u", 15, 8))>;
+
+// Constructors and destructors return 'this' in the ARM C++ ABI; since 'this'
+// and the pointer return value are both passed in R0 in these cases, this can
+// be partially modelled by treating R0 as a callee-saved register
+// Only the resulting RegMask is used; the SaveList is ignored
+def CSR_AAPCS_ThisReturn : CalleeSavedRegs<(add LR, R11, R10, R9, R8, R7, R6,
+ R5, R4, (sequence "D%u", 15, 8),
+ R0)>;
+
+// iOS ABI deviates from ARM standard ABI. R9 is not a callee-saved register.
+// Also save R7-R4 first to match the stack frame fixed spill areas.
+def CSR_iOS : CalleeSavedRegs<(add LR, R7, R6, R5, R4, (sub CSR_AAPCS, R9))>;
+
+def CSR_iOS_ThisReturn : CalleeSavedRegs<(add LR, R7, R6, R5, R4,
+ (sub CSR_AAPCS_ThisReturn, R9))>;
+
+// The "interrupt" attribute is used to generate code that is acceptable in
+// exception-handlers of various kinds. It makes us use a different return
+// instruction (handled elsewhere) and affects which registers we must return to
+// our "caller" in the same state as we receive them.
+
+// For most interrupts, all registers except SP and LR are shared with
+// user-space. We mark LR to be saved anyway, since this is what the ARM backend
+// generally does rather than tracking its liveness as a normal register.
+def CSR_GenericInt : CalleeSavedRegs<(add LR, (sequence "R%u", 12, 0))>;
+
+// The fast interrupt handlers have more private state and get their own copies
+// of R8-R12, in addition to SP and LR. As before, mark LR for saving too.
+
+// FIXME: we mark R11 as callee-saved since it's often the frame-pointer, and
+// current frame lowering expects to encounter it while processing callee-saved
+// registers.
+def CSR_FIQ : CalleeSavedRegs<(add LR, R11, (sequence "R%u", 7, 0))>;
+
+