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llvm-mirror/lib/CodeGen/SafeStackLayout.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

84 lines
2.4 KiB
C++

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