Change StackDirection from StackGrowsUp to StackGrowsDown.

The following improvements are accomplished as a result of applying this patch:
- Fixed frame objects' offsets (relative to either the virtual frame pointer or
  the stack pointer) are set before instruction selection is completed. There is
  no need to wait until Prologue/Epilogue Insertion is run to set them.
- Calculation of final offsets of fixed frame objects is straightforward. It is
  no longer necessary to assign negative offsets to fixed objects for incoming
  arguments in order to distinguish them from the others.
- Since a fixed object has its relative offset set during instruction
  selection, there is no need to conservatively set its alignment to 4.
- It is no longer necessary to reorder non-fixed frame objects in 
  MipsFrameLowering::adjustMipsStackFrame.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131915 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 59 deletions

diff --git a/lib/Target/Mips/MipsMachineFunction.h b/lib/Target/Mips/MipsMachineFunction.h
index 3f6b670..1d3c7fa 100644
--- a/lib/Target/Mips/MipsMachineFunction.h
+++ b/lib/Target/Mips/MipsMachineFunction.h
@@ -34,35 +34,6 @@ private:
   int CPUTopSavedRegOff;
   int FPUTopSavedRegOff;
 
-  /// MipsFIHolder - Holds a FrameIndex and it's Stack Pointer Offset
-  struct MipsFIHolder {
-
-    int FI;
-    int SPOffset;
-
-    MipsFIHolder(int FrameIndex, int StackPointerOffset)
-      : FI(FrameIndex), SPOffset(StackPointerOffset) {}
-  };
-
-  /// When PIC is used the GP must be saved on the stack on the function
-  /// prologue and must be reloaded from this stack location after every
-  /// call. A reference to its stack location and frame index must be kept
-  /// to be used on emitPrologue and processFunctionBeforeFrameFinalized.
-  MipsFIHolder GPHolder;
-
-  /// On LowerFormalArguments the stack size is unknown, so the Stack
-  /// Pointer Offset calculation of "not in register arguments" must be
-  /// postponed to emitPrologue.
-  SmallVector<MipsFIHolder, 16> FnLoadArgs;
-  bool HasLoadArgs;
-
-  // When VarArgs, we must write registers back to caller stack, preserving
-  // on register arguments. Since the stack size is unknown on
-  // LowerFormalArguments, the Stack Pointer Offset calculation must be
-  // postponed to emitPrologue.
-  SmallVector<MipsFIHolder, 4> FnStoreVarArgs;
-  bool HasStoreVarArgs;
-
   /// SRetReturnReg - Some subtargets require that sret lowering includes
   /// returning the value of the returned struct in a register. This field
   /// holds the virtual register into which the sret argument is passed.
@@ -88,8 +59,7 @@ private:
 public:
   MipsFunctionInfo(MachineFunction& MF)
   : CPUTopSavedRegOff(0),
-    FPUTopSavedRegOff(0), GPHolder(-1,-1), HasLoadArgs(false),
-    HasStoreVarArgs(false), SRetReturnReg(0), GlobalBaseReg(0),
+    FPUTopSavedRegOff(0), SRetReturnReg(0), GlobalBaseReg(0),
     VarArgsFrameIndex(0), InArgFIRange(std::make_pair(-1, 0)),
     OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), HasCall(false),
     MaxCallFrameSize(-1)
@@ -116,36 +86,11 @@ public:
     OutArgFIRange.second = LastFI;
   }
 
-  int getGPStackOffset() const { return GPHolder.SPOffset; }
-  int getGPFI() const { return GPHolder.FI; }
-  void setGPStackOffset(int Off) { GPHolder.SPOffset = Off; }
-  void setGPFI(int FI) { GPHolder.FI = FI; }
-  bool needGPSaveRestore() const { return GPHolder.SPOffset != -1; }
+  int getGPFI() const { return GPFI; }
+  void setGPFI(int FI) { GPFI = FI; }
+  bool needGPSaveRestore() const { return getGPFI(); }
   bool isGPFI(int FI) const { return GPFI && GPFI == FI; }
 
-  bool hasLoadArgs() const { return HasLoadArgs; }
-  bool hasStoreVarArgs() const { return HasStoreVarArgs; }
-
-  void recordLoadArgsFI(int FI, int SPOffset) {
-    if (!HasLoadArgs) HasLoadArgs=true;
-    FnLoadArgs.push_back(MipsFIHolder(FI, SPOffset));
-  }
-  void recordStoreVarArgsFI(int FI, int SPOffset) {
-    if (!HasStoreVarArgs) HasStoreVarArgs=true;
-    FnStoreVarArgs.push_back(MipsFIHolder(FI, SPOffset));
-  }
-
-  void adjustLoadArgsFI(MachineFrameInfo *MFI) const {
-    if (!hasLoadArgs()) return;
-    for (unsigned i = 0, e = FnLoadArgs.size(); i != e; ++i)
-      MFI->setObjectOffset( FnLoadArgs[i].FI, FnLoadArgs[i].SPOffset );
-  }
-  void adjustStoreVarArgsFI(MachineFrameInfo *MFI) const {
-    if (!hasStoreVarArgs()) return;
-    for (unsigned i = 0, e = FnStoreVarArgs.size(); i != e; ++i)
-      MFI->setObjectOffset( FnStoreVarArgs[i].FI, FnStoreVarArgs[i].SPOffset );
-  }
-
   unsigned getSRetReturnReg() const { return SRetReturnReg; }
   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }