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       1             : //===- SafeStackLayout.h - SafeStack frame layout --------------*- C++ -*--===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : 
      10             : #ifndef LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
      11             : #define LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
      12             : 
      13             : #include "SafeStackColoring.h"
      14             : #include "llvm/ADT/DenseMap.h"
      15             : #include "llvm/ADT/SmallVector.h"
      16             : 
      17             : namespace llvm {
      18             : 
      19             : class raw_ostream;
      20             : class Value;
      21             : 
      22             : namespace safestack {
      23             : 
      24             : /// Compute the layout of an unsafe stack frame.
      25             : class StackLayout {
      26             :   unsigned MaxAlignment;
      27             : 
      28         906 :   struct StackRegion {
      29             :     unsigned Start;
      30             :     unsigned End;
      31             :     StackColoring::LiveRange Range;
      32             : 
      33             :     StackRegion(unsigned Start, unsigned End,
      34             :                 const StackColoring::LiveRange &Range)
      35         250 :         : Start(Start), End(End), Range(Range) {}
      36             :   };
      37             : 
      38             :   /// The list of current stack regions, sorted by StackRegion::Start.
      39             :   SmallVector<StackRegion, 16> Regions;
      40             : 
      41         424 :   struct StackObject {
      42             :     const Value *Handle;
      43             :     unsigned Size, Alignment;
      44             :     StackColoring::LiveRange Range;
      45             :   };
      46             : 
      47             :   SmallVector<StackObject, 8> StackObjects;
      48             : 
      49             :   DenseMap<const Value *, unsigned> ObjectOffsets;
      50             :   DenseMap<const Value *, unsigned> ObjectAlignments;
      51             : 
      52             :   void layoutObject(StackObject &Obj);
      53             : 
      54             : public:
      55         304 :   StackLayout(unsigned StackAlignment) : MaxAlignment(StackAlignment) {}
      56             : 
      57             :   /// Add an object to the stack frame. Value pointer is opaque and used as a
      58             :   /// handle to retrieve the object's offset in the frame later.
      59             :   void addObject(const Value *V, unsigned Size, unsigned Alignment,
      60             :                  const StackColoring::LiveRange &Range);
      61             : 
      62             :   /// Run the layout computation for all previously added objects.
      63             :   void computeLayout();
      64             : 
      65             :   /// Returns the offset to the object start in the stack frame.
      66           0 :   unsigned getObjectOffset(const Value *V) { return ObjectOffsets[V]; }
      67             : 
      68             :   /// Returns the alignment of the object
      69           0 :   unsigned getObjectAlignment(const Value *V) { return ObjectAlignments[V]; }
      70             : 
      71             :   /// Returns the size of the entire frame.
      72           0 :   unsigned getFrameSize() { return Regions.empty() ? 0 : Regions.back().End; }
      73             : 
      74             :   /// Returns the alignment of the frame.
      75           0 :   unsigned getFrameAlignment() { return MaxAlignment; }
      76             : 
      77             :   void print(raw_ostream &OS);
      78             : };
      79             : 
      80             : } // end namespace safestack
      81             : 
      82             : } // end namespace llvm
      83             : 
      84             : #endif // LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H