Transforms/Utils/ASanStackFrameLayout.h

0001 //===- ASanStackFrameLayout.h - ComputeASanStackFrameLayout -----*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 // This header defines ComputeASanStackFrameLayout and auxiliary data structs.
0010 //
0011 //===----------------------------------------------------------------------===//
0012 #ifndef LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
0013 #define LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H
0014 #include "llvm/ADT/SmallString.h"
0015 #include "llvm/ADT/SmallVector.h"
0016
0017 namespace llvm {
0018
0019 class AllocaInst;
0020
0021 // These magic constants should be the same as in
0022 // in asan_internal.h from ASan runtime in compiler-rt.
0023 static const int kAsanStackLeftRedzoneMagic = 0xf1;
0024 static const int kAsanStackMidRedzoneMagic = 0xf2;
0025 static const int kAsanStackRightRedzoneMagic = 0xf3;
0026 static const int kAsanStackUseAfterReturnMagic = 0xf5;
0027 static const int kAsanStackUseAfterScopeMagic = 0xf8;
0028
0029 // Input/output data struct for ComputeASanStackFrameLayout.
0030 struct ASanStackVariableDescription {
0031   const char *Name;    // Name of the variable that will be displayed by asan
0032                        // if a stack-related bug is reported.
0033   uint64_t Size;       // Size of the variable in bytes.
0034   size_t LifetimeSize; // Size in bytes to use for lifetime analysis check.
0035                        // Will be rounded up to Granularity.
0036   uint64_t Alignment;  // Alignment of the variable (power of 2).
0037   AllocaInst *AI;      // The actual AllocaInst.
0038   size_t Offset;       // Offset from the beginning of the frame;
0039                        // set by ComputeASanStackFrameLayout.
0040   unsigned Line;       // Line number.
0041 };
0042
0043 // Output data struct for ComputeASanStackFrameLayout.
0044 struct ASanStackFrameLayout {
0045   uint64_t Granularity;     // Shadow granularity.
0046   uint64_t FrameAlignment;  // Alignment for the entire frame.
0047   uint64_t FrameSize;       // Size of the frame in bytes.
0048 };
0049
0050 ASanStackFrameLayout ComputeASanStackFrameLayout(
0051     // The array of stack variables. The elements may get reordered and changed.
0052     SmallVectorImpl<ASanStackVariableDescription> &Vars,
0053     // AddressSanitizer's shadow granularity. Usually 8, may also be 16, 32, 64.
0054     uint64_t Granularity,
0055     // The minimal size of the left-most redzone (header).
0056     // At least 4 pointer sizes, power of 2, and >= Granularity.
0057     // The resulting FrameSize should be multiple of MinHeaderSize.
0058     uint64_t MinHeaderSize);
0059
0060 // Compute frame description, see DescribeAddressIfStack in ASan runtime.
0061 SmallString<64> ComputeASanStackFrameDescription(
0062     const SmallVectorImpl<ASanStackVariableDescription> &Vars);
0063
0064 // Returns shadow bytes with marked red zones. This shadow represents the state
0065 // if the stack frame when all local variables are inside of the own scope.
0066 SmallVector<uint8_t, 64>
0067 GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars,
0068                const ASanStackFrameLayout &Layout);
0069
0070 // Returns shadow bytes with marked red zones and after scope. This shadow
0071 // represents the state if the stack frame when all local variables are outside
0072 // of the own scope.
0073 SmallVector<uint8_t, 64> GetShadowBytesAfterScope(
0074     // The array of stack variables. The elements may get reordered and changed.
0075     const SmallVectorImpl<ASanStackVariableDescription> &Vars,
0076     const ASanStackFrameLayout &Layout);
0077
0078 } // llvm namespace
0079
0080 #endif  // LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H