1//===- ASanStackFrameLayout.h - ComputeASanStackFrameLayout -----*- 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-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This header defines ComputeASanStackFrameLayout and auxiliary data structs.
10//
11//===----------------------------------------------------------------------===//
12#ifndef LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
13#define LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
14#include "llvm/ADT/SmallString.h"
15#include "llvm/ADT/SmallVector.h"
16
17namespace llvm {
18
19class AllocaInst;
20
21// These magic constants should be the same as in
22// in asan_internal.h from ASan runtime in compiler-rt.
23static const int kAsanStackLeftRedzoneMagic = 0xf1;
24static const int kAsanStackMidRedzoneMagic = 0xf2;
25static const int kAsanStackRightRedzoneMagic = 0xf3;
26static const int kAsanStackUseAfterReturnMagic = 0xf5;
27static const int kAsanStackUseAfterScopeMagic = 0xf8;
28
29// Input/output data struct for ComputeASanStackFrameLayout.
30struct ASanStackVariableDescription {
31 const char *Name; // Name of the variable that will be displayed by asan
32 // if a stack-related bug is reported.
33 uint64_t Size; // Size of the variable in bytes.
34 size_t LifetimeSize; // Size in bytes to use for lifetime analysis check.
35 // Will be rounded up to Granularity.
36 size_t Alignment; // Alignment of the variable (power of 2).
37 AllocaInst *AI; // The actual AllocaInst.
38 size_t Offset; // Offset from the beginning of the frame;
39 // set by ComputeASanStackFrameLayout.
40 unsigned Line; // Line number.
41};
42
43// Output data struct for ComputeASanStackFrameLayout.
44struct ASanStackFrameLayout {
45 size_t Granularity; // Shadow granularity.
46 size_t FrameAlignment; // Alignment for the entire frame.
47 size_t FrameSize; // Size of the frame in bytes.
48};
49
50ASanStackFrameLayout ComputeASanStackFrameLayout(
51 // The array of stack variables. The elements may get reordered and changed.
52 SmallVectorImpl<ASanStackVariableDescription> &Vars,
53 // AddressSanitizer's shadow granularity. Usually 8, may also be 16, 32, 64.
54 size_t Granularity,
55 // The minimal size of the left-most redzone (header).
56 // At least 4 pointer sizes, power of 2, and >= Granularity.
57 // The resulting FrameSize should be multiple of MinHeaderSize.
58 size_t MinHeaderSize);
59
60// Compute frame description, see DescribeAddressIfStack in ASan runtime.
61SmallString<64> ComputeASanStackFrameDescription(
62 const SmallVectorImpl<ASanStackVariableDescription> &Vars);
63
64// Returns shadow bytes with marked red zones. This shadow represents the state
65// if the stack frame when all local variables are inside of the own scope.
66SmallVector<uint8_t, 64>
67GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars,
68 const ASanStackFrameLayout &Layout);
69
70// Returns shadow bytes with marked red zones and after scope. This shadow
71// represents the state if the stack frame when all local variables are outside
72// of the own scope.
73SmallVector<uint8_t, 64> GetShadowBytesAfterScope(
74 // The array of stack variables. The elements may get reordered and changed.
75 const SmallVectorImpl<ASanStackVariableDescription> &Vars,
76 const ASanStackFrameLayout &Layout);
77
78} // llvm namespace
79
80#endif // LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
81