Vendor import of llvm tags/RELEASE_33/final r183502 (effectively, 3.3vendor/llvm/llvm-release_33-r183502

release):
http://llvm.org/svn/llvm-project/llvm/tags/RELEASE_33/final@183502

1 files changed, 86 insertions, 23 deletions

diff --git a/lib/Target/Sparc/SparcCallingConv.td b/lib/Target/Sparc/SparcCallingConv.td
index b38ac616dcf4..54784e018834 100644
--- a/lib/Target/Sparc/SparcCallingConv.td
+++ b/lib/Target/Sparc/SparcCallingConv.td
@@ -12,25 +12,9 @@
 //===----------------------------------------------------------------------===//
 
 //===----------------------------------------------------------------------===//
-// Return Value Calling Conventions
+// SPARC v8 32-bit.
 //===----------------------------------------------------------------------===//
 
-// Sparc 32-bit C return-value convention.
-def RetCC_Sparc32 : CallingConv<[
-  CCIfType<[i32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
-  CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>,
-  CCIfType<[f64], CCAssignToReg<[D0, D1]>>
-]>;
-
-// Sparc 64-bit C return-value convention.
-def RetCC_Sparc64 : CallingConv<[
-  CCIfType<[i32], CCPromoteToType<i64>>,
-  CCIfType<[i64], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
-  CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>,
-  CCIfType<[f64], CCAssignToReg<[D0, D1]>>
-]>;
-
-// Sparc 32-bit C Calling convention.
 def CC_Sparc32 : CallingConv<[
   //Custom assign SRet to [sp+64].
   CCIfSRet<CCCustom<"CC_Sparc_Assign_SRet">>,
@@ -43,14 +27,93 @@ def CC_Sparc32 : CallingConv<[
   CCAssignToStack<4, 4>
 ]>;
 
-// Sparc 64-bit C Calling convention.
+def RetCC_Sparc32 : CallingConv<[
+  CCIfType<[i32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
+  CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>,
+  CCIfType<[f64], CCAssignToReg<[D0, D1]>>
+]>;
+
+
+//===----------------------------------------------------------------------===//
+// 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 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>>,
-  // Integer arguments get passed in integer registers if there is space.
-  CCIfType<[i64], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
-  // FIXME: Floating point arguments.
 
-  // Alternatively, they are assigned to the stack in 8-byte aligned units.
-  CCAssignToStack<8, 8>
+  // Custom assignment is required because stack space is reserved for all
+  // arguments whether they are passed in registers or not.
+  CCCustom<"CC_Sparc64_Full">
 ]>;