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84 lines
2.4 KiB
84 lines
2.4 KiB
//===- SafeStackLayout.h - SafeStack frame layout --------------*- C++ -*--===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
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#define LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Analysis/StackLifetime.h"
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namespace llvm {
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class raw_ostream;
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class Value;
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namespace safestack {
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/// Compute the layout of an unsafe stack frame.
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class StackLayout {
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unsigned MaxAlignment;
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struct StackRegion {
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unsigned Start;
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unsigned End;
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StackLifetime::LiveRange Range;
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StackRegion(unsigned Start, unsigned End,
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const StackLifetime::LiveRange &Range)
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: Start(Start), End(End), Range(Range) {}
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};
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/// The list of current stack regions, sorted by StackRegion::Start.
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SmallVector<StackRegion, 16> Regions;
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struct StackObject {
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const Value *Handle;
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unsigned Size, Alignment;
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StackLifetime::LiveRange Range;
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};
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SmallVector<StackObject, 8> StackObjects;
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DenseMap<const Value *, unsigned> ObjectOffsets;
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DenseMap<const Value *, unsigned> ObjectAlignments;
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void layoutObject(StackObject &Obj);
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public:
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StackLayout(unsigned StackAlignment) : MaxAlignment(StackAlignment) {}
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/// Add an object to the stack frame. Value pointer is opaque and used as a
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/// handle to retrieve the object's offset in the frame later.
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void addObject(const Value *V, unsigned Size, unsigned Alignment,
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const StackLifetime::LiveRange &Range);
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/// Run the layout computation for all previously added objects.
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void computeLayout();
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/// Returns the offset to the object start in the stack frame.
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unsigned getObjectOffset(const Value *V) { return ObjectOffsets[V]; }
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/// Returns the alignment of the object
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unsigned getObjectAlignment(const Value *V) { return ObjectAlignments[V]; }
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/// Returns the size of the entire frame.
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unsigned getFrameSize() { return Regions.empty() ? 0 : Regions.back().End; }
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/// Returns the alignment of the frame.
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unsigned getFrameAlignment() { return MaxAlignment; }
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void print(raw_ostream &OS);
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};
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} // end namespace safestack
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} // end namespace llvm
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#endif // LLVM_LIB_CODEGEN_SAFESTACKLAYOUT_H
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