-//===- SparcCallingConv.td - Calling Conventions Sparc -----*- tablegen -*-===//
-//
+//===-- SparcCallingConv.td - Calling Conventions Sparc ----*- 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 the Sparc architectures.
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
-// Return Value Calling Conventions
+// SPARC v8 32-bit.
//===----------------------------------------------------------------------===//
-// Sparc 32-bit C return-value convention.
+def CC_Sparc32 : CallingConv<[
+ // Custom assign SRet to [sp+64].
+ CCIfSRet<CCCustom<"CC_Sparc_Assign_SRet">>,
+ // i32 f32 arguments get passed in integer registers if there is space.
+ CCIfType<[i32, f32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
+ // f64 arguments are split and passed through registers or through stack.
+ CCIfType<[f64], CCCustom<"CC_Sparc_Assign_Split_64">>,
+ // As are v2i32 arguments (this would be the default behavior for
+ // v2i32 if it wasn't allocated to the IntPair register-class)
+ CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Split_64">>,
+
+
+ // Alternatively, they are assigned to the stack in 4-byte aligned units.
+ CCAssignToStack<4, 4>
+]>;
+
def RetCC_Sparc32 : CallingConv<[
CCIfType<[i32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
- CCIfType<[f32], CCAssignToReg<[F1, F3, F5, F7]>>,
- CCIfType<[f64], CCAssignToReg<[D0, D2]>>
+ CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>,
+ CCIfType<[f64], CCAssignToReg<[D0, D1]>>,
+ CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Ret_Split_64">>
]>;
-// Sparc 32-bit C Calling convention.
-def CC_Sparc32 : CallingConv<[
- // All arguments get passed in integer registers if there is space.
- CCIfType<[i32, f32, f64], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
-
- // Alternatively, they are assigned to the stack in 4-byte aligned units.
- CCAssignToStack<4, 4>
+
+//===----------------------------------------------------------------------===//
+// SPARC v9 64-bit.
+//===----------------------------------------------------------------------===//
+//
+// The 64-bit ABI conceptually assigns all function arguments to a parameter
+// array starting at [%fp+BIAS+128] in the callee's stack frame. All arguments
+// occupy a multiple of 8 bytes in the array. Integer arguments are extended to
+// 64 bits by the caller. Floats are right-aligned in their 8-byte slot, the
+// first 4 bytes in the slot are undefined.
+//
+// The integer registers %i0 to %i5 shadow the first 48 bytes of the parameter
+// array at fixed offsets. Integer arguments are promoted to registers when
+// possible.
+//
+// The floating point registers %f0 to %f31 shadow the first 128 bytes of the
+// parameter array at fixed offsets. Float and double parameters are promoted
+// to these registers when possible.
+//
+// Structs up to 16 bytes in size are passed by value. They are right-aligned
+// in one or two 8-byte slots in the parameter array. Struct members are
+// promoted to both floating point and integer registers when possible. A
+// struct containing two floats would thus be passed in %f0 and %f1, while two
+// float function arguments would occupy 8 bytes each, and be passed in %f1 and
+// %f3.
+//
+// When a struct { int, float } is passed by value, the int goes in the high
+// bits of an integer register while the float goes in a floating point
+// register.
+//
+// The difference is encoded in LLVM IR using the inreg atttribute on function
+// arguments:
+//
+// C: void f(float, float);
+// IR: declare void f(float %f1, float %f3)
+//
+// C: void f(struct { float f0, f1; });
+// IR: declare void f(float inreg %f0, float inreg %f1)
+//
+// C: void f(int, float);
+// IR: declare void f(int signext %i0, float %f3)
+//
+// C: void f(struct { int i0high; float f1; });
+// IR: declare void f(i32 inreg %i0high, float inreg %f1)
+//
+// Two ints in a struct are simply coerced to i64:
+//
+// C: void f(struct { int i0high, i0low; });
+// IR: declare void f(i64 %i0.coerced)
+//
+// The frontend and backend divide the task of producing ABI compliant code for
+// C functions. The C frontend will:
+//
+// - Annotate integer arguments with zeroext or signext attributes.
+//
+// - Split structs into one or two 64-bit sized chunks, or 32-bit chunks with
+// inreg attributes.
+//
+// - Pass structs larger than 16 bytes indirectly with an explicit pointer
+// argument. The byval attribute is not used.
+//
+// The backend will:
+//
+// - Assign all arguments to 64-bit aligned stack slots, 32-bits for inreg.
+//
+// - Promote to integer or floating point registers depending on type.
+//
+// Function return values are passed exactly like function arguments, except a
+// struct up to 32 bytes in size can be returned in registers.
+
+// Function arguments AND most return values.
+def CC_Sparc64 : CallingConv<[
+ // The frontend uses the inreg flag to indicate i32 and float arguments from
+ // structs. These arguments are not promoted to 64 bits, but they can still
+ // be assigned to integer and float registers.
+ CCIfInReg<CCIfType<[i32, f32], CCCustom<"CC_Sparc64_Half">>>,
+
+ // All integers are promoted to i64 by the caller.
+ CCIfType<[i32], CCPromoteToType<i64>>,
+
+ // Custom assignment is required because stack space is reserved for all
+ // arguments whether they are passed in registers or not.
+ CCCustom<"CC_Sparc64_Full">
]>;
+
+def RetCC_Sparc64 : CallingConv<[
+ // A single f32 return value always goes in %f0. The ABI doesn't specify what
+ // happens to multiple f32 return values outside a struct.
+ CCIfType<[f32], CCCustom<"CC_Sparc64_Half">>,
+
+ // Otherwise, return values are passed exactly like arguments.
+ CCDelegateTo<CC_Sparc64>
+]>;
+
+// Callee-saved registers are handled by the register window mechanism.
+def CSR : CalleeSavedRegs<(add)> {
+ let OtherPreserved = (add (sequence "I%u", 0, 7),
+ (sequence "L%u", 0, 7));
+}
+
+// Callee-saved registers for calls with ReturnsTwice attribute.
+def RTCSR : CalleeSavedRegs<(add)> {
+ let OtherPreserved = (add I6, I7);
+}
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