Add new CC lowering rule: provide a list of registers, which can be 'shadowed',

when some another register is used for argument passing.
Currently is used on Win64.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49079 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 21 insertions, 6 deletions

diff --git a/lib/Target/TargetCallingConv.td b/lib/Target/TargetCallingConv.td
index 05d505a88d..908e16ed5e 100644
--- a/lib/Target/TargetCallingConv.td
+++ b/lib/Target/TargetCallingConv.td
@@ -59,6 +59,14 @@ class CCAssignToReg<list<Register> regList> : CCAction {
   list<Register> RegList = regList;
 }
 
+/// CCAssignToRegWithShadow - Same as CCAssignToReg, but with list of registers
+/// which became shadowed, when some register is used.
+class CCAssignToRegWithShadow<list<Register> regList,
+                              list<Register> shadowList> : CCAction {
+  list<Register> RegList = regList;
+  list<Register> ShadowRegList = shadowList;
+}
+
 /// CCAssignToStack - This action always matches: it assigns the value to a
 /// stack slot of the specified size and alignment on the stack.  If size is
 /// zero then the ABI size is used; if align is zero then the ABI alignment
diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td
index 310dbb7671..c60611d065 100644
--- a/lib/Target/X86/X86CallingConv.td
+++ b/lib/Target/X86/X86CallingConv.td
@@ -158,22 +158,29 @@ def CC_X86_64_C : CallingConv<[
 def CC_X86_Win64_C : CallingConv<[
   // FIXME: Handle byval stuff.
   // FIXME: Handle fp80.
-  // FIXME: Handle shadowed arguments.
-  // FIXME: Handle nested functions.
+  // FIXME: Handle varargs.
 
   // Promote i8/i16 arguments to i32.
   CCIfType<[i8, i16], CCPromoteToType<i32>>,
 
+  // The 'nest' parameter, if any, is passed in R10.
+  CCIfNest<CCAssignToReg<[R10]>>,
+
   // The first 4 integer arguments are passed in integer registers.
-  CCIfType<[i32], CCAssignToReg<[ECX, EDX, R8D, R9D]>>,
-  CCIfType<[i64], CCAssignToReg<[RCX, RDX, R8 , R9 ]>>,
+  CCIfType<[i32], CCAssignToRegWithShadow<[ECX , EDX , R8D , R9D ],
+                                          [XMM0, XMM1, XMM2, XMM3]>>,
+  CCIfType<[i64], CCAssignToRegWithShadow<[RCX , RDX , R8  , R9  ],
+                                          [XMM0, XMM1, XMM2, XMM3]>>,
 
   // The first 4 FP/Vector arguments are passed in XMM registers.
   CCIfType<[f32, f64, v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
-              CCAssignToReg<[XMM0, XMM1, XMM2, XMM3]>>,
+           CCAssignToRegWithShadow<[XMM0, XMM1, XMM2, XMM3],
+                                   [RCX , RDX , R8  , R9  ]>>,
 
   // The first 4 MMX vector arguments are passed in GPRs.
-  CCIfType<[v8i8, v4i16, v2i32, v1i64], CCAssignToReg<[RCX, RDX, R8, R9]>>,
+  CCIfType<[v8i8, v4i16, v2i32, v1i64],
+           CCAssignToRegWithShadow<[RCX , RDX , R8  , R9  ],
+                                   [XMM0, XMM1, XMM2, XMM3]>>,
 
   // Integer/FP values get stored in stack slots that are 8 bytes in size and
   // 16-byte aligned if there are no more registers to hold them.