1 files changed, 25 insertions, 17 deletions

diff --git a/llvm/include/llvm/CodeGen/CallingConvLower.h b/llvm/include/llvm/CodeGen/CallingConvLower.h
index 3d70f5a2d8e9..a99519252cf9 100644
--- a/llvm/include/llvm/CodeGen/CallingConvLower.h
+++ b/llvm/include/llvm/CodeGen/CallingConvLower.h
@@ -91,14 +91,14 @@ public:
     return getReg(ValNo, ValVT, RegNo, LocVT, HTP, /*IsCustom=*/true);
   }
 
-  static CCValAssign getMem(unsigned ValNo, MVT ValVT, unsigned Offset,
+  static CCValAssign getMem(unsigned ValNo, MVT ValVT, int64_t Offset,
                             MVT LocVT, LocInfo HTP, bool IsCustom = false) {
     CCValAssign Ret(HTP, ValNo, ValVT, LocVT, IsCustom);
-    Ret.Data = int64_t(Offset);
+    Ret.Data = Offset;
     return Ret;
   }
 
-  static CCValAssign getCustomMem(unsigned ValNo, MVT ValVT, unsigned Offset,
+  static CCValAssign getCustomMem(unsigned ValNo, MVT ValVT, int64_t Offset,
                                   MVT LocVT, LocInfo HTP) {
     return getMem(ValNo, ValVT, Offset, LocVT, HTP, /*IsCustom=*/true);
   }
@@ -112,7 +112,7 @@ public:
 
   void convertToReg(unsigned RegNo) { Data = Register(RegNo); }
 
-  void convertToMem(unsigned Offset) { Data = int64_t(Offset); }
+  void convertToMem(int64_t Offset) { Data = Offset; }
 
   unsigned getValNo() const { return ValNo; }
   MVT getValVT() const { return ValVT; }
@@ -124,7 +124,7 @@ public:
   bool needsCustom() const { return isCustom; }
 
   Register getLocReg() const { return std::get<Register>(Data); }
-  unsigned getLocMemOffset() const { return std::get<int64_t>(Data); }
+  int64_t getLocMemOffset() const { return std::get<int64_t>(Data); }
   unsigned getExtraInfo() const { return std::get<unsigned>(Data); }
 
   MVT getLocVT() const { return LocVT; }
@@ -174,8 +174,10 @@ private:
   const TargetRegisterInfo &TRI;
   SmallVectorImpl<CCValAssign> &Locs;
   LLVMContext &Context;
+  // True if arguments should be allocated at negative offsets.
+  bool NegativeOffsets;
 
-  unsigned StackSize;
+  uint64_t StackSize;
   Align MaxStackArgAlign;
   SmallVector<uint32_t, 16> UsedRegs;
   SmallVector<CCValAssign, 4> PendingLocs;
@@ -224,8 +226,9 @@ private:
   unsigned InRegsParamsProcessed;
 
 public:
-  CCState(CallingConv::ID CC, bool isVarArg, MachineFunction &MF,
-          SmallVectorImpl<CCValAssign> &locs, LLVMContext &C);
+  CCState(CallingConv::ID CC, bool IsVarArg, MachineFunction &MF,
+          SmallVectorImpl<CCValAssign> &Locs, LLVMContext &Context,
+          bool NegativeOffsets = false);
 
   void addLoc(const CCValAssign &V) {
     Locs.push_back(V);
@@ -237,12 +240,12 @@ public:
   bool isVarArg() const { return IsVarArg; }
 
   /// Returns the size of the currently allocated portion of the stack.
-  unsigned getStackSize() const { return StackSize; }
+  uint64_t getStackSize() const { return StackSize; }
 
   /// getAlignedCallFrameSize - Return the size of the call frame needed to
   /// be able to store all arguments and such that the alignment requirement
   /// of each of the arguments is satisfied.
-  unsigned getAlignedCallFrameSize() const {
+  uint64_t getAlignedCallFrameSize() const {
     return alignTo(StackSize, MaxStackArgAlign);
   }
 
@@ -396,21 +399,26 @@ public:
 
   /// AllocateStack - Allocate a chunk of stack space with the specified size
   /// and alignment.
-  unsigned AllocateStack(unsigned Size, Align Alignment) {
-    StackSize = alignTo(StackSize, Alignment);
-    unsigned Result = StackSize;
-    StackSize += Size;
+  int64_t AllocateStack(unsigned Size, Align Alignment) {
+    int64_t Offset;
+    if (NegativeOffsets) {
+      StackSize = alignTo(StackSize + Size, Alignment);
+      Offset = -StackSize;
+    } else {
+      Offset = alignTo(StackSize, Alignment);
+      StackSize = Offset + Size;
+    }
     MaxStackArgAlign = std::max(Alignment, MaxStackArgAlign);
     ensureMaxAlignment(Alignment);
-    return Result;
+    return Offset;
   }
 
   void ensureMaxAlignment(Align Alignment);
 
   /// Version of AllocateStack with list of extra registers to be shadowed.
   /// Note that, unlike AllocateReg, this shadows ALL of the shadow registers.
-  unsigned AllocateStack(unsigned Size, Align Alignment,
-                         ArrayRef<MCPhysReg> ShadowRegs) {
+  int64_t AllocateStack(unsigned Size, Align Alignment,
+                        ArrayRef<MCPhysReg> ShadowRegs) {
     for (MCPhysReg Reg : ShadowRegs)
       MarkAllocated(Reg);
     return AllocateStack(Size, Alignment);