fixup! add hooks for insert/prepend/setCurrentPosition

Author: Michael137

libcxxabi/src/demangle/Utility.h

@@ -93,6 +93,12 @@ class OutputBuffer {
   virtual void printLeft(const Node &N);
   virtual void printRight(const Node &N);
 
+  /// Called when we write to this object anywhere other than the end.
+  virtual void notifyInsertion(size_t /*Position*/, size_t /*Count*/) {}
+
+  /// Called when we reset the \c CurrentPosition of this object.
+  virtual void notifyPositionChanged(size_t /*OldPos*/, size_t /*NewPos*/) {}
+
   /// If a ParameterPackExpansion (or similar type) is encountered, the offset
   /// into the pack that we're currently printing.
   unsigned CurrentPackIndex = std::numeric_limits<unsigned>::max();
@@ -131,6 +137,8 @@ class OutputBuffer {
   OutputBuffer &prepend(std::string_view R) {
     size_t Size = R.size();
 
+    notifyInsertion(/*Position=*/0, /*Count=*/Size);
+
     grow(Size);
     std::memmove(Buffer + Size, Buffer, CurrentPosition);
     std::memcpy(Buffer, &*R.begin(), Size);
@@ -171,14 +179,20 @@ class OutputBuffer {
     DEMANGLE_ASSERT(Pos <= CurrentPosition, "");
     if (N == 0)
       return;
+
+    notifyInsertion(Pos, N);
+
     grow(N);
     std::memmove(Buffer + Pos + N, Buffer + Pos, CurrentPosition - Pos);
     std::memcpy(Buffer + Pos, S, N);
     CurrentPosition += N;
   }
 
   size_t getCurrentPosition() const { return CurrentPosition; }
-  void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; }
+  void setCurrentPosition(size_t NewPos) {
+    notifyPositionChanged(CurrentPosition, NewPos);
+    CurrentPosition = NewPos;
+  }
 
   char back() const {
     DEMANGLE_ASSERT(CurrentPosition, "");

llvm/include/llvm/Demangle/ItaniumDemangle.h

@@ -38,8 +38,10 @@
 DEMANGLE_NAMESPACE_BEGIN
 
 template <class T, size_t N> class PODSmallVector {
-  static_assert(std::is_trivial<T>::value,
-                "T is required to be a trivial type");
+  static_assert(std::is_trivially_copyable<T>::value,
+                "T is required to be a trivially copyable type");
+  static_assert(std::is_trivially_default_constructible<T>::value,
+                "T is required to be trivially default constructible");
   T *First = nullptr;
   T *Last = nullptr;
   T *Cap = nullptr;
@@ -5752,14 +5754,16 @@ struct FloatData<double>
 template <>
 struct FloatData<long double>
 {
-#if defined(__mips__) && defined(__mips_n64) || defined(__aarch64__) || \
-    defined(__wasm__) || defined(__riscv) || defined(__loongarch__) || \
-    defined(__ve__)
-    static const size_t mangled_size = 32;
-#elif defined(__arm__) || defined(__mips__) || defined(__hexagon__)
-    static const size_t mangled_size = 16;
+#if __LDBL_MANT_DIG__ == 113 || __LDBL_MANT_DIG__ == 106
+  static const size_t mangled_size = 32;
+#elif __LDBL_MANT_DIG__ == 53 || defined(_MSC_VER)
+  // MSVC doesn't define __LDBL_MANT_DIG__, but it has long double equal to
+  // regular double on all current architectures.
+  static const size_t mangled_size = 16;
+#elif __LDBL_MANT_DIG__ == 64
+  static const size_t mangled_size = 20;
 #else
-    static const size_t mangled_size = 20;  // May need to be adjusted to 16 or 24 on other platforms
+#error Unknown size for __LDBL_MANT_DIG__
 #endif
     // `-0x1.ffffffffffffffffffffffffffffp+16383` + 'L' + '\0' == 42 bytes.
     // 28 'f's * 4 bits == 112 bits, which is the number of mantissa bits.

llvm/include/llvm/Demangle/Utility.h

@@ -93,6 +93,12 @@ class OutputBuffer {
   virtual void printLeft(const Node &N);
   virtual void printRight(const Node &N);
 
+  /// Called when we write to this object anywhere other than the end.
+  virtual void notifyInsertion(size_t /*Position*/, size_t /*Count*/) {}
+
+  /// Called when we reset the \c CurrentPosition of this object.
+  virtual void notifyPositionChanged(size_t /*OldPos*/, size_t /*NewPos*/) {}
+
   /// If a ParameterPackExpansion (or similar type) is encountered, the offset
   /// into the pack that we're currently printing.
   unsigned CurrentPackIndex = std::numeric_limits<unsigned>::max();
@@ -131,6 +137,8 @@ class OutputBuffer {
   OutputBuffer &prepend(std::string_view R) {
     size_t Size = R.size();
 
+    notifyInsertion(/*Position=*/0, /*Count=*/Size);
+
     grow(Size);
     std::memmove(Buffer + Size, Buffer, CurrentPosition);
     std::memcpy(Buffer, &*R.begin(), Size);
@@ -171,14 +179,20 @@ class OutputBuffer {
     DEMANGLE_ASSERT(Pos <= CurrentPosition, "");
     if (N == 0)
       return;
+
+    notifyInsertion(Pos, N);
+
     grow(N);
     std::memmove(Buffer + Pos + N, Buffer + Pos, CurrentPosition - Pos);
     std::memcpy(Buffer + Pos, S, N);
     CurrentPosition += N;
   }
 
   size_t getCurrentPosition() const { return CurrentPosition; }
-  void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; }
+  void setCurrentPosition(size_t NewPos) {
+    notifyPositionChanged(CurrentPosition, NewPos);
+    CurrentPosition = NewPos;
+  }
 
   char back() const {
     DEMANGLE_ASSERT(CurrentPosition, "");

llvm/unittests/Demangle/OutputBufferTest.cpp

@@ -93,3 +93,40 @@ TEST(OutputBufferTest, Extend) {
 
   std::free(OB.getBuffer());
 }
+
+TEST(OutputBufferTest, Notifications) {
+  struct MyOutputBuffer : public OutputBuffer {
+    size_t Inserted = 0;
+    size_t LatestPos = 0;
+
+    void notifyPositionChanged(size_t OldPos, size_t NewPos) override {
+      LatestPos = NewPos;
+    }
+
+    void notifyInsertion(size_t Position, size_t Count) override {
+      Inserted += Count;
+      LatestPos = Position;
+    }
+  } OB;
+
+  OB.prepend("n");
+  EXPECT_EQ(OB.Inserted, 1U);
+  EXPECT_EQ(OB.LatestPos, 0U);
+
+  OB.prepend("");
+  EXPECT_EQ(OB.Inserted, 1U);
+  EXPECT_EQ(OB.LatestPos, 0U);
+
+  OB.prepend("abc");
+  EXPECT_EQ(OB.Inserted, 4U);
+  EXPECT_EQ(OB.LatestPos, 0U);
+
+  OB.insert(2, "abc", 3U);
+  EXPECT_EQ(OB.Inserted, 7U);
+  EXPECT_EQ(OB.LatestPos, 2U);
+
+  OB.setCurrentPosition(3U);
+  EXPECT_EQ(OB.LatestPos, 3U);
+
+  std::free(OB.getBuffer());
+}