caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[asan] Separate calculation of ShadowBytes from calculating ASanStackFrameLayout

Browse Source 
Summary: No functional changes, just refactoring to make D23947 simpler.

Reviewers: eugenis

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D23954

llvm-svn: 279982
This commit is contained in:
Vitaly Buka
2016-08-29 17:41:29 +00:00
parent ac644fa917
commit db331d8be7
4 changed files with 115 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

80
llvm/lib/Transforms/Utils/ASanStackFrameLayout.cpp
View File

@@ -47,15 +47,14 @@ static size_t VarAndRedzoneSize(size_t Size, size_t Alignment) {
return alignTo(Res, Alignment);
}
void
ASanStackFrameLayout
ComputeASanStackFrameLayout(SmallVectorImpl<ASanStackVariableDescription> &Vars,
size_t Granularity, size_t MinHeaderSize,
ASanStackFrameLayout *Layout) {
size_t Granularity, size_t MinHeaderSize) {
assert(Granularity >= 8 && Granularity <= 64 &&
(Granularity & (Granularity - 1)) == 0);
assert(MinHeaderSize >= 16 && (MinHeaderSize & (MinHeaderSize - 1)) == 0 &&
MinHeaderSize >= Granularity);
size_t NumVars = Vars.size();
const size_t NumVars = Vars.size();
assert(NumVars > 0);
for (size_t i = 0; i < NumVars; i++)
Vars[i].Alignment = std::max(Vars[i].Alignment, kMinAlignment);
@@ -64,13 +63,13 @@ ComputeASanStackFrameLayout(SmallVectorImpl<ASanStackVariableDescription> &Vars,
SmallString<2048> StackDescriptionStorage;
raw_svector_ostream StackDescription(StackDescriptionStorage);
StackDescription << NumVars;
Layout->FrameAlignment = std::max(Granularity, Vars[0].Alignment);
SmallVector<uint8_t, 64> &SB(Layout->ShadowBytes);
SB.clear();
ASanStackFrameLayout Layout;
Layout.Granularity = Granularity;
Layout.FrameAlignment = std::max(Granularity, Vars[0].Alignment);
size_t Offset = std::max(std::max(MinHeaderSize, Granularity),
Vars[0].Alignment);
assert((Offset % Granularity) == 0);
SB.insert(SB.end(), Offset / Granularity, kAsanStackLeftRedzoneMagic);
for (size_t i = 0; i < NumVars; i++) {
bool IsLast = i == NumVars - 1;
size_t Alignment = std::max(Granularity, Vars[i].Alignment);
@@ -78,7 +77,7 @@ ComputeASanStackFrameLayout(SmallVectorImpl<ASanStackVariableDescription> &Vars,
size_t Size = Vars[i].Size;
const char *Name = Vars[i].Name;
assert((Alignment & (Alignment - 1)) == 0);
assert(Layout->FrameAlignment >= Alignment);
assert(Layout.FrameAlignment >= Alignment);
assert((Offset % Alignment) == 0);
assert(Size > 0);
assert(Vars[i].LifetimeSize <= Size);
@@ -87,31 +86,54 @@ ComputeASanStackFrameLayout(SmallVectorImpl<ASanStackVariableDescription> &Vars,
size_t NextAlignment = IsLast ? Granularity
: std::max(Granularity, Vars[i + 1].Alignment);
size_t SizeWithRedzone = VarAndRedzoneSize(Vars[i].Size, NextAlignment);
size_t LifetimeShadowSize =
(Vars[i].LifetimeSize + Granularity - 1) / Granularity;
SB.insert(SB.end(), LifetimeShadowSize, kAsanStackUseAfterScopeMagic);
if (Size / Granularity >= LifetimeShadowSize) {
SB.insert(SB.end(), Size / Granularity - LifetimeShadowSize, 0);
if (Size % Granularity)
SB.insert(SB.end(), Size % Granularity);
}
SB.insert(SB.end(), (SizeWithRedzone - Size) / Granularity,
IsLast ? kAsanStackRightRedzoneMagic
: kAsanStackMidRedzoneMagic);
Vars[i].Offset = Offset;
Offset += SizeWithRedzone;
assert(Offset == SB.size() * Granularity);
}
if (Offset % MinHeaderSize) {
size_t ExtraRedzone = MinHeaderSize - (Offset % MinHeaderSize);
SB.insert(SB.end(), ExtraRedzone / Granularity,
kAsanStackRightRedzoneMagic);
Offset += ExtraRedzone;
Offset += MinHeaderSize - (Offset % MinHeaderSize);
}
Layout->DescriptionString = StackDescription.str();
Layout->FrameSize = Offset;
assert((Layout->FrameSize % MinHeaderSize) == 0);
assert(Layout->FrameSize / Granularity == Layout->ShadowBytes.size());
Layout.DescriptionString = StackDescription.str();
Layout.FrameSize = Offset;
assert((Layout.FrameSize % MinHeaderSize) == 0);
return Layout;
}
SmallVector<uint8_t, 64>
GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars,
const ASanStackFrameLayout &Layout) {
SmallVector<uint8_t, 64> SB;
SB.clear();
const size_t NumVars = Vars.size();
assert(NumVars > 0);
const size_t Granularity = Layout.Granularity;
SB.resize(Vars[0].Offset / Granularity, kAsanStackLeftRedzoneMagic);
for (const auto &Var : Vars) {
SB.resize(Var.Offset / Granularity, kAsanStackMidRedzoneMagic);
SB.resize(SB.size() + Var.Size / Granularity, 0);
if (Var.Size % Granularity)
SB.push_back(Var.Size % Granularity);
}
SB.resize(Layout.FrameSize / Granularity, kAsanStackRightRedzoneMagic);
return SB;
}
SmallVector<uint8_t, 64> GetShadowBytesAfterScope(
const SmallVectorImpl<ASanStackVariableDescription> &Vars,
const ASanStackFrameLayout &Layout) {
SmallVector<uint8_t, 64> SB = GetShadowBytes(Vars, Layout);
const size_t Granularity = Layout.Granularity;
for (const auto &Var : Vars) {
const size_t LifetimeShadowSize =
(Var.LifetimeSize + Granularity - 1) / Granularity;
const size_t Offset = Var.Offset / Granularity;
std::fill(SB.begin() + Offset, SB.begin() + Offset + LifetimeShadowSize,
kAsanStackUseAfterScopeMagic);
}
return SB;
}
} // llvm namespace