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 | |
17 | namespace llvm { |
18 | |
19 | class AllocaInst; |
20 | |
21 | // These magic constants should be the same as in |
22 | // in asan_internal.h from ASan runtime in compiler-rt. |
23 | static const int kAsanStackLeftRedzoneMagic = 0xf1; |
24 | static const int kAsanStackMidRedzoneMagic = 0xf2; |
25 | static const int kAsanStackRightRedzoneMagic = 0xf3; |
26 | static const int kAsanStackUseAfterReturnMagic = 0xf5; |
27 | static const int kAsanStackUseAfterScopeMagic = 0xf8; |
28 | |
29 | // Input/output data struct for ComputeASanStackFrameLayout. |
30 | struct 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 | uint64_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. |
44 | struct ASanStackFrameLayout { |
45 | uint64_t Granularity; // Shadow granularity. |
46 | uint64_t FrameAlignment; // Alignment for the entire frame. |
47 | uint64_t FrameSize; // Size of the frame in bytes. |
48 | }; |
49 | |
50 | ASanStackFrameLayout 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 | uint64_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 | uint64_t ); |
59 | |
60 | // Compute frame description, see DescribeAddressIfStack in ASan runtime. |
61 | SmallString<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. |
66 | SmallVector<uint8_t, 64> |
67 | GetShadowBytes(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. |
73 | SmallVector<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 | |