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1//===- SafeStackLayout.h - SafeStack frame layout --------------*- C++ -*--===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H10#define LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H11 12#include "llvm/ADT/DenseMap.h"13#include "llvm/ADT/SmallVector.h"14#include "llvm/Analysis/StackLifetime.h"15#include "llvm/Support/Alignment.h"16 17namespace llvm {18 19class raw_ostream;20class Value;21 22namespace safestack {23 24/// Compute the layout of an unsafe stack frame.25class StackLayout {26 Align MaxAlignment;27 28 struct StackRegion {29 unsigned Start;30 unsigned End;31 StackLifetime::LiveRange Range;32 33 StackRegion(unsigned Start, unsigned End,34 const StackLifetime::LiveRange &Range)35 : 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 struct StackObject {42 const Value *Handle;43 unsigned Size;44 Align Alignment;45 StackLifetime::LiveRange Range;46 };47 48 SmallVector<StackObject, 8> StackObjects;49 50 DenseMap<const Value *, unsigned> ObjectOffsets;51 DenseMap<const Value *, Align> ObjectAlignments;52 53 void layoutObject(StackObject &Obj);54 55public:56 StackLayout(Align StackAlignment) : MaxAlignment(StackAlignment) {}57 58 /// Add an object to the stack frame. Value pointer is opaque and used as a59 /// handle to retrieve the object's offset in the frame later.60 void addObject(const Value *V, unsigned Size, Align Alignment,61 const StackLifetime::LiveRange &Range);62 63 /// Run the layout computation for all previously added objects.64 void computeLayout();65 66 /// Returns the offset to the object start in the stack frame.67 unsigned getObjectOffset(const Value *V) { return ObjectOffsets[V]; }68 69 /// Returns the alignment of the object70 Align getObjectAlignment(const Value *V) { return ObjectAlignments[V]; }71 72 /// Returns the size of the entire frame.73 unsigned getFrameSize() { return Regions.empty() ? 0 : Regions.back().End; }74 75 /// Returns the alignment of the frame.76 Align getFrameAlignment() { return MaxAlignment; }77 78 void print(raw_ostream &OS);79};80 81} // end namespace safestack82 83} // end namespace llvm84 85#endif // LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H86