1 //===-- ASanStackFrameLayout.cpp - helper for AddressSanitizer ------------===//
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
23 // It is tempting to also sort variables by size so that larger variables
38 // The larger the variable Size the larger is the redzone.
39 // The resulting frame size is a multiple of Alignment.
40 static uint64_t VarAndRedzoneSize(uint64_t Size, uint64_t Granularity,  in VarAndRedzoneSize()  argument
43   if (Size <= 4)  Res = 16;  in VarAndRedzoneSize()
44   else if (Size <= 16) Res = 32;  in VarAndRedzoneSize()
45   else if (Size <= 128) Res = Size + 32;  in VarAndRedzoneSize()
46   else if (Size <= 512) Res = Size + 64;  in VarAndRedzoneSize()
47   else if (Size <= 4096) Res = Size + 128;  in VarAndRedzoneSize()
48   else                   Res = Size + 256;  in VarAndRedzoneSize()
49   return alignTo(std::max(Res, 2 * Granularity), Alignment);  in VarAndRedzoneSize()
56          (Granularity & (Granularity - 1)) == 0);  in ComputeASanStackFrameLayout()
57   assert(MinHeaderSize >= 16 && (MinHeaderSize & (MinHeaderSize - 1)) == 0 &&  in ComputeASanStackFrameLayout()
59   const size_t NumVars = Vars.size();  in ComputeASanStackFrameLayout()
62     Vars[i].Alignment = std::max(Vars[i].Alignment, kMinAlignment);  in ComputeASanStackFrameLayout()
68   Layout.FrameAlignment = std::max(Granularity, Vars[0].Alignment);  in ComputeASanStackFrameLayout()
70       std::max(std::max(MinHeaderSize, Granularity), Vars[0].Alignment);  in ComputeASanStackFrameLayout()
73     bool IsLast = i == NumVars - 1;  in ComputeASanStackFrameLayout()
74     uint64_t Alignment = std::max(Granularity, Vars[i].Alignment);  in ComputeASanStackFrameLayout()
76     uint64_t Size = Vars[i].Size;  in ComputeASanStackFrameLayout()  local
77     assert((Alignment & (Alignment - 1)) == 0);  in ComputeASanStackFrameLayout()
80     assert(Size > 0);  in ComputeASanStackFrameLayout()
82         IsLast ? Granularity : std::max(Granularity, Vars[i + 1].Alignment);  in ComputeASanStackFrameLayout()
84         VarAndRedzoneSize(Size, Granularity, NextAlignment);  in ComputeASanStackFrameLayout()
89     Offset += MinHeaderSize - (Offset % MinHeaderSize);  in ComputeASanStackFrameLayout()
100   StackDescription << Vars.size();  in ComputeASanStackFrameDescription()
108     StackDescription << " " << Var.Offset << " " << Var.Size << " "  in ComputeASanStackFrameDescription()
109                      << Name.size() << " " << Name;  in ComputeASanStackFrameDescription()
117   assert(Vars.size() > 0);  in GetShadowBytes()
125     SB.resize(SB.size() + Var.Size / Granularity, 0);  in GetShadowBytes()
126     if (Var.Size % Granularity)  in GetShadowBytes()
127       SB.push_back(Var.Size % Granularity);  in GetShadowBytes()
140     assert(Var.LifetimeSize <= Var.Size);  in GetShadowBytesAfterScope()
142         (Var.LifetimeSize + Granularity - 1) / Granularity;  in GetShadowBytesAfterScope()