include/llvm/Transforms/Utils/ASanStackFrameLayout.h

   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   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.
  44 struct 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
  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     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.
  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