Imported Upstream version 5.18.0.205

Former-commit-id: 7f59f7e792705db773f1caecdaa823092f4e2927

external/llvm/lib/Target/AVR/AVRCallingConv.td

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+//===-- AVRCallingConv.td - Calling Conventions for AVR ----*- tablegen -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// This describes the calling conventions for AVR architecture.
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// AVR Return Value Calling Convention
+//===----------------------------------------------------------------------===//
+
+def RetCC_AVR : CallingConv
+<[
+  // i8 is returned in R24.
+  CCIfType<[i8], CCAssignToReg<[R24]>>,
+
+  // i16 are returned in R25:R24, R23:R22, R21:R20 and R19:R18.
+  CCIfType<[i16], CCAssignToReg<[R25R24, R23R22, R21R20, R19R18]>>
+]>;
+
+// Special return value calling convention for runtime functions.
+def RetCC_AVR_BUILTIN : CallingConv
+<[
+  CCIfType<[i8], CCAssignToReg<[R24,R25]>>,
+  CCIfType<[i16], CCAssignToReg<[R23R22, R25R24]>>
+]>;
+
+//===----------------------------------------------------------------------===//
+// AVR Argument Calling Conventions
+//===----------------------------------------------------------------------===//
+
+// The calling conventions are implemented in custom C++ code
+
+// Calling convention for variadic functions.
+def ArgCC_AVR_Vararg : CallingConv
+<[
+  // i16 are always passed through the stack with an alignment of 1.
+  CCAssignToStack<2, 1>
+]>;
+
+// Special argument calling convention for
+// division runtime functions.
+def ArgCC_AVR_BUILTIN_DIV : CallingConv
+<[
+  CCIfType<[i8], CCAssignToReg<[R24,R22]>>,
+  CCIfType<[i16], CCAssignToReg<[R25R24, R23R22]>>
+]>;
+
+//===----------------------------------------------------------------------===//
+// Callee-saved register lists.
+//===----------------------------------------------------------------------===//
+
+def CSR_Normal : CalleeSavedRegs<(add R29, R28, (sequence "R%u", 17, 2))>;
+def CSR_Interrupts : CalleeSavedRegs<(add (sequence "R%u", 31, 0))>;