1//===- ASanStackFrameLayout.h - ComputeASanStackFrameLayout -----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This header defines ComputeASanStackFrameLayout and auxiliary data structs.
11//
12//===----------------------------------------------------------------------===//
13#ifndef LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
14#define LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
15#include "llvm/ADT/SmallString.h"
16#include "llvm/ADT/SmallVector.h"
17
18namespace llvm {
19
20class AllocaInst;
21
22// These magic constants should be the same as in
23// in asan_internal.h from ASan runtime in compiler-rt.
24static const int kAsanStackLeftRedzoneMagic = 0xf1;
25static const int kAsanStackMidRedzoneMagic = 0xf2;
26static const int kAsanStackRightRedzoneMagic = 0xf3;
27
28// Input/output data struct for ComputeASanStackFrameLayout.
29struct ASanStackVariableDescription {
30  const char *Name;  // Name of the variable that will be displayed by asan
31                     // if a stack-related bug is reported.
32  uint64_t Size;     // Size of the variable in bytes.
33  size_t Alignment;  // Alignment of the variable (power of 2).
34  AllocaInst *AI;    // The actual AllocaInst.
35  size_t Offset;     // Offset from the beginning of the frame;
36                     // set by ComputeASanStackFrameLayout.
37};
38
39// Output data struct for ComputeASanStackFrameLayout.
40struct ASanStackFrameLayout {
41  // Frame description, see DescribeAddressIfStack in ASan runtime.
42  SmallString<64> DescriptionString;
43  // The contents of the shadow memory for the stack frame that we need
44  // to set at function entry.
45  SmallVector<uint8_t, 64> ShadowBytes;
46  size_t FrameAlignment;  // Alignment for the entire frame.
47  size_t FrameSize;       // Size of the frame in bytes.
48};
49
50void 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    // The result is put here.
60    ASanStackFrameLayout *Layout);
61
62} // llvm namespace
63
64#endif  // LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
65