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 15 namespace llvm { 16 namespace safestack { 17 18 /// Compute the layout of an unsafe stack frame. 19 class StackLayout { 20 unsigned MaxAlignment; 21 22 struct StackRegion { 23 unsigned Start; 24 unsigned End; 25 StackColoring::LiveRange Range; 26 StackRegion(unsigned Start, unsigned End, 27 const StackColoring::LiveRange &Range) 28 : Start(Start), End(End), Range(Range) {} 29 }; 30 /// The list of current stack regions, sorted by StackRegion::Start. 31 SmallVector<StackRegion, 16> Regions; 32 33 struct StackObject { 34 const Value *Handle; 35 unsigned Size, Alignment; 36 StackColoring::LiveRange Range; 37 }; 38 SmallVector<StackObject, 8> StackObjects; 39 40 DenseMap<const Value *, unsigned> ObjectOffsets; 41 42 void layoutObject(StackObject &Obj); 43 44 public: 45 StackLayout(unsigned StackAlignment) : MaxAlignment(StackAlignment) {} 46 /// Add an object to the stack frame. Value pointer is opaque and used as a 47 /// handle to retrieve the object's offset in the frame later. 48 void addObject(const Value *V, unsigned Size, unsigned Alignment, 49 const StackColoring::LiveRange &Range); 50 51 /// Run the layout computation for all previously added objects. 52 void computeLayout(); 53 54 /// Returns the offset to the object start in the stack frame. 55 unsigned getObjectOffset(const Value *V) { return ObjectOffsets[V]; } 56 57 /// Returns the size of the entire frame. 58 unsigned getFrameSize() { return Regions.empty() ? 0 : Regions.back().End; } 59 60 /// Returns the alignment of the frame. 61 unsigned getFrameAlignment() { return MaxAlignment; } 62 void print(raw_ostream &OS); 63 }; 64 65 } // namespace safestack 66 } // namespace llvm 67 68 #endif // LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H 69
