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 18 namespace llvm { 19 20 class AllocaInst; 21 22 // These magic constants should be the same as in 23 // in asan_internal.h from ASan runtime in compiler-rt. 24 static const int kAsanStackLeftRedzoneMagic = 0xf1; 25 static const int kAsanStackMidRedzoneMagic = 0xf2; 26 static const int kAsanStackRightRedzoneMagic = 0xf3; 27 static const int kAsanStackUseAfterReturnMagic = 0xf5; 28 static const int kAsanStackUseAfterScopeMagic = 0xf8; 29 30 // Input/output data struct for ComputeASanStackFrameLayout. 31 struct ASanStackVariableDescription { 32 const char *Name; // Name of the variable that will be displayed by asan 33 // if a stack-related bug is reported. 34 uint64_t Size; // Size of the variable in bytes. 35 size_t LifetimeSize; // Size in bytes to use for lifetime analysis check. 36 // Will be rounded up to Granularity. 37 size_t Alignment; // Alignment of the variable (power of 2). 38 AllocaInst *AI; // The actual AllocaInst. 39 size_t Offset; // Offset from the beginning of the frame; 40 // set by ComputeASanStackFrameLayout. 41 unsigned Line; // Line number. 42 }; 43 44 // Output data struct for ComputeASanStackFrameLayout. 45 struct ASanStackFrameLayout { 46 size_t Granularity; // Shadow granularity. 47 size_t FrameAlignment; // Alignment for the entire frame. 48 size_t FrameSize; // Size of the frame in bytes. 49 }; 50 51 ASanStackFrameLayout ComputeASanStackFrameLayout( 52 // The array of stack variables. The elements may get reordered and changed. 53 SmallVectorImpl<ASanStackVariableDescription> &Vars, 54 // AddressSanitizer's shadow granularity. Usually 8, may also be 16, 32, 64. 55 size_t Granularity, 56 // The minimal size of the left-most redzone (header). 57 // At least 4 pointer sizes, power of 2, and >= Granularity. 58 // The resulting FrameSize should be multiple of MinHeaderSize. 59 size_t MinHeaderSize); 60 61 // Compute frame description, see DescribeAddressIfStack in ASan runtime. 62 SmallString<64> ComputeASanStackFrameDescription( 63 const SmallVectorImpl<ASanStackVariableDescription> &Vars); 64 65 // Returns shadow bytes with marked red zones. This shadow represents the state 66 // if the stack frame when all local variables are inside of the own scope. 67 SmallVector<uint8_t, 64> 68 GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars, 69 const ASanStackFrameLayout &Layout); 70 71 // Returns shadow bytes with marked red zones and after scope. This shadow 72 // represents the state if the stack frame when all local variables are outside 73 // of the own scope. 74 SmallVector<uint8_t, 64> GetShadowBytesAfterScope( 75 // The array of stack variables. The elements may get reordered and changed. 76 const SmallVectorImpl<ASanStackVariableDescription> &Vars, 77 const ASanStackFrameLayout &Layout); 78 79 } // llvm namespace 80 81 #endif // LLVM_TRANSFORMS_UTILS_ASANSTACKFRAMELAYOUT_H 82
