[XCore] Support functions returning more than 4 words.

Summary:
If a function returns a large struct by value return the first 4 words
in registers and the rest on the stack in a location reserved by the
caller. This is needed to support the xC language which supports
functions returning an arbitrary number of return values.

Reviewers: robertlytton

Reviewed By: robertlytton

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2889

llvm-svn: 202397

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Target/XCore/XCoreMachineFunctionInfo.h b/llvm/lib/Target/XCore/XCoreMachineFunctionInfo.h
index f1777a87e11..2649300b44d 100644
--- a/llvm/lib/Target/XCore/XCoreMachineFunctionInfo.h
+++ b/llvm/lib/Target/XCore/XCoreMachineFunctionInfo.h
@@ -33,6 +33,8 @@ class XCoreFunctionInfo : public MachineFunctionInfo {
   int FPSpillSlot;
   bool EHSpillSlotSet;
   int EHSpillSlot[2];
+  unsigned ReturnStackOffset;
+  bool ReturnStackOffsetSet;
   int VarArgsFrameIndex;
   mutable int CachedEStackSize;
   std::vector<std::pair<MCSymbol*, CalleeSavedInfo> > SpillLabels;
@@ -42,6 +44,7 @@ public:
     LRSpillSlotSet(false),
     FPSpillSlotSet(false),
     EHSpillSlotSet(false),
+    ReturnStackOffsetSet(false),
     VarArgsFrameIndex(0),
     CachedEStackSize(-1) {}
   
@@ -78,6 +81,17 @@ public:
     return EHSpillSlot;
   }
 
+  void setReturnStackOffset(unsigned value) {
+    assert(!ReturnStackOffsetSet && "Return stack offset set twice");
+    ReturnStackOffset = value;
+    ReturnStackOffsetSet = true;
+  }
+
+  unsigned getReturnStackOffset() const {
+    assert(ReturnStackOffsetSet && "Return stack offset not set");
+    return ReturnStackOffset;
+  }
+
   bool isLargeFrame(const MachineFunction &MF) const;
 
   std::vector<std::pair<MCSymbol*, CalleeSavedInfo> > &getSpillLabels() {