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//===- ASanStackFrameLayout.h - ComputeASanStackFrameLayout -----*- 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
//
//===----------------------------------------------------------------------===//
//
// This header defines ComputeASanStackFrameLayout and auxiliary data structs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
#define LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
class AllocaInst;
// These magic constants should be the same as in
// in asan_internal.h from ASan runtime in compiler-rt.
static const int kAsanStackLeftRedzoneMagic = 0xf1;
static const int kAsanStackMidRedzoneMagic = 0xf2;
static const int kAsanStackRightRedzoneMagic = 0xf3;
static const int kAsanStackUseAfterReturnMagic = 0xf5;
static const int kAsanStackUseAfterScopeMagic = 0xf8;
// Input/output data struct for ComputeASanStackFrameLayout.
struct ASanStackVariableDescription {
const char *Name; // Name of the variable that will be displayed by asan
// if a stack-related bug is reported.
uint64_t Size; // Size of the variable in bytes.
size_t LifetimeSize; // Size in bytes to use for lifetime analysis check.
// Will be rounded up to Granularity.
uint64_t Alignment; // Alignment of the variable (power of 2).
AllocaInst *AI; // The actual AllocaInst.
size_t Offset; // Offset from the beginning of the frame;
// set by ComputeASanStackFrameLayout.
unsigned Line; // Line number.
};
// Output data struct for ComputeASanStackFrameLayout.
struct ASanStackFrameLayout {
uint64_t Granularity; // Shadow granularity.
uint64_t FrameAlignment; // Alignment for the entire frame.
uint64_t FrameSize; // Size of the frame in bytes.
};
ASanStackFrameLayout ComputeASanStackFrameLayout(
// The array of stack variables. The elements may get reordered and changed.
SmallVectorImpl<ASanStackVariableDescription> &Vars,
// AddressSanitizer's shadow granularity. Usually 8, may also be 16, 32, 64.
uint64_t Granularity,
// The minimal size of the left-most redzone (header).
// At least 4 pointer sizes, power of 2, and >= Granularity.
// The resulting FrameSize should be multiple of MinHeaderSize.
uint64_t MinHeaderSize);
// Compute frame description, see DescribeAddressIfStack in ASan runtime.
SmallString<64> ComputeASanStackFrameDescription(
const SmallVectorImpl<ASanStackVariableDescription> &Vars);
// Returns shadow bytes with marked red zones. This shadow represents the state
// if the stack frame when all local variables are inside of the own scope.
SmallVector<uint8_t, 64>
GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars,
const ASanStackFrameLayout &Layout);
// Returns shadow bytes with marked red zones and after scope. This shadow
// represents the state if the stack frame when all local variables are outside
// of the own scope.
SmallVector<uint8_t, 64> GetShadowBytesAfterScope(
// The array of stack variables. The elements may get reordered and changed.
const SmallVectorImpl<ASanStackVariableDescription> &Vars,
const ASanStackFrameLayout &Layout);
} // llvm namespace
#endif // LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
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