intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 152 insertions, 0 deletions

diff --git a/contrib/libs/llvm12/lib/Transforms/Utils/ASanStackFrameLayout.cpp b/contrib/libs/llvm12/lib/Transforms/Utils/ASanStackFrameLayout.cpp
new file mode 100644
index 00000000000..01912297324
--- /dev/null
+++ b/contrib/libs/llvm12/lib/Transforms/Utils/ASanStackFrameLayout.cpp
@@ -0,0 +1,152 @@
+//===-- ASanStackFrameLayout.cpp - helper for AddressSanitizer ------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Definition of ComputeASanStackFrameLayout (see ASanStackFrameLayout.h).
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/ScopedPrinter.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+
+namespace llvm {
+
+// We sort the stack variables by alignment (largest first) to minimize
+// unnecessary large gaps due to alignment.
+// It is tempting to also sort variables by size so that larger variables
+// have larger redzones at both ends. But reordering will make report analysis
+// harder, especially when temporary unnamed variables are present.
+// So, until we can provide more information (type, line number, etc)
+// for the stack variables we avoid reordering them too much.
+static inline bool CompareVars(const ASanStackVariableDescription &a,
+                               const ASanStackVariableDescription &b) {
+  return a.Alignment > b.Alignment;
+}
+
+// We also force minimal alignment for all vars to kMinAlignment so that vars
+// with e.g. alignment 1 and alignment 16 do not get reordered by CompareVars.
+static const size_t kMinAlignment = 16;
+
+// We want to add a full redzone after every variable.
+// The larger the variable Size the larger is the redzone.
+// The resulting frame size is a multiple of Alignment.
+static size_t VarAndRedzoneSize(size_t Size, size_t Granularity,
+                                size_t Alignment) {
+  size_t Res = 0;
+  if (Size <= 4)  Res = 16;
+  else if (Size <= 16) Res = 32;
+  else if (Size <= 128) Res = Size + 32;
+  else if (Size <= 512) Res = Size + 64;
+  else if (Size <= 4096) Res = Size + 128;
+  else                   Res = Size + 256;
+  return alignTo(std::max(Res, 2 * Granularity), Alignment);
+}
+
+ASanStackFrameLayout
+ComputeASanStackFrameLayout(SmallVectorImpl<ASanStackVariableDescription> &Vars,
+                            size_t Granularity, size_t MinHeaderSize) {
+  assert(Granularity >= 8 && Granularity <= 64 &&
+         (Granularity & (Granularity - 1)) == 0);
+  assert(MinHeaderSize >= 16 && (MinHeaderSize & (MinHeaderSize - 1)) == 0 &&
+         MinHeaderSize >= Granularity);
+  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);
+
+  llvm::stable_sort(Vars, CompareVars);
+
+  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);
+  for (size_t i = 0; i < NumVars; i++) {
+    bool IsLast = i == NumVars - 1;
+    size_t Alignment = std::max(Granularity, Vars[i].Alignment);
+    (void)Alignment;  // Used only in asserts.
+    size_t Size = Vars[i].Size;
+    assert((Alignment & (Alignment - 1)) == 0);
+    assert(Layout.FrameAlignment >= Alignment);
+    assert((Offset % Alignment) == 0);
+    assert(Size > 0);
+    size_t NextAlignment = IsLast ? Granularity
+                   : std::max(Granularity, Vars[i + 1].Alignment);
+    size_t SizeWithRedzone = VarAndRedzoneSize(Size, Granularity,
+                                               NextAlignment);
+    Vars[i].Offset = Offset;
+    Offset += SizeWithRedzone;
+  }
+  if (Offset % MinHeaderSize) {
+    Offset += MinHeaderSize - (Offset % MinHeaderSize);
+  }
+  Layout.FrameSize = Offset;
+  assert((Layout.FrameSize % MinHeaderSize) == 0);
+  return Layout;
+}
+
+SmallString<64> ComputeASanStackFrameDescription(
+    const SmallVectorImpl<ASanStackVariableDescription> &Vars) {
+  SmallString<2048> StackDescriptionStorage;
+  raw_svector_ostream StackDescription(StackDescriptionStorage);
+  StackDescription << Vars.size();
+
+  for (const auto &Var : Vars) {
+    std::string Name = Var.Name;
+    if (Var.Line) {
+      Name += ":";
+      Name += to_string(Var.Line);
+    }
+    StackDescription << " " << Var.Offset << " " << Var.Size << " "
+                     << Name.size() << " " << Name;
+  }
+  return StackDescription.str();
+}
+
+SmallVector<uint8_t, 64>
+GetShadowBytes(const SmallVectorImpl<ASanStackVariableDescription> &Vars,
+               const ASanStackFrameLayout &Layout) {
+  assert(Vars.size() > 0);
+  SmallVector<uint8_t, 64> SB;
+  SB.clear();
+  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) {
+    assert(Var.LifetimeSize <= Var.Size);
+    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