1 files changed, 193 insertions, 0 deletions
diff --git a/lib/AST/Interp/Pointer.cpp b/lib/AST/Interp/Pointer.cpp
new file mode 100644
index 0000000000000..1a10723aaca53
--- /dev/null
+++ b/lib/AST/Interp/Pointer.cpp
@@ -0,0 +1,193 @@
+//===--- Pointer.cpp - Types for the constexpr VM ---------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "Pointer.h"
+#include "Block.h"
+#include "Function.h"
+#include "PrimType.h"
+
+using namespace clang;
+using namespace clang::interp;
+
+Pointer::Pointer(Block *Pointee) : Pointer(Pointee, 0, 0) {}
+
+Pointer::Pointer(const Pointer &P) : Pointer(P.Pointee, P.Base, P.Offset) {}
+
+Pointer::Pointer(Pointer &&P)
+    : Pointee(P.Pointee), Base(P.Base), Offset(P.Offset) {
+  if (Pointee)
+    Pointee->movePointer(&P, this);
+}
+
+Pointer::Pointer(Block *Pointee, unsigned Base, unsigned Offset)
+    : Pointee(Pointee), Base(Base), Offset(Offset) {
+  assert((Base == RootPtrMark || Base % alignof(void *) == 0) && "wrong base");
+  if (Pointee)
+    Pointee->addPointer(this);
+}
+
+Pointer::~Pointer() {
+  if (Pointee) {
+    Pointee->removePointer(this);
+    Pointee->cleanup();
+  }
+}
+
+void Pointer::operator=(const Pointer &P) {
+  Block *Old = Pointee;
+
+  if (Pointee)
+    Pointee->removePointer(this);
+
+  Offset = P.Offset;
+  Base = P.Base;
+
+  Pointee = P.Pointee;
+  if (Pointee)
+    Pointee->addPointer(this);
+
+  if (Old)
+    Old->cleanup();
+}
+
+void Pointer::operator=(Pointer &&P) {
+  Block *Old = Pointee;
+
+  if (Pointee)
+    Pointee->removePointer(this);
+
+  Offset = P.Offset;
+  Base = P.Base;
+
+  Pointee = P.Pointee;
+  if (Pointee)
+    Pointee->movePointer(&P, this);
+
+  if (Old)
+    Old->cleanup();
+}
+
+APValue Pointer::toAPValue() const {
+  APValue::LValueBase Base;
+  llvm::SmallVector<APValue::LValuePathEntry, 5> Path;
+  CharUnits Offset;
+  bool IsNullPtr;
+  bool IsOnePastEnd;
+
+  if (isZero()) {
+    Base = static_cast<const Expr *>(nullptr);
+    IsNullPtr = true;
+    IsOnePastEnd = false;
+    Offset = CharUnits::Zero();
+  } else {
+    // Build the lvalue base from the block.
+    Descriptor *Desc = getDeclDesc();
+    if (auto *VD = Desc->asValueDecl())
+      Base = VD;
+    else if (auto *E = Desc->asExpr())
+      Base = E;
+    else
+      llvm_unreachable("Invalid allocation type");
+
+    // Not a null pointer.
+    IsNullPtr = false;
+
+    if (isUnknownSizeArray()) {
+      IsOnePastEnd = false;
+      Offset = CharUnits::Zero();
+    } else {
+      // TODO: compute the offset into the object.
+      Offset = CharUnits::Zero();
+
+      // Build the path into the object.
+      Pointer Ptr = *this;
+      while (Ptr.isField()) {
+        if (Ptr.isArrayElement()) {
+          Path.push_back(APValue::LValuePathEntry::ArrayIndex(Ptr.getIndex()));
+          Ptr = Ptr.getArray();
+        } else {
+          // TODO: figure out if base is virtual
+          bool IsVirtual = false;
+
+          // Create a path entry for the field.
+          Descriptor *Desc = Ptr.getFieldDesc();
+          if (auto *BaseOrMember = Desc->asDecl()) {
+            Path.push_back(APValue::LValuePathEntry({BaseOrMember, IsVirtual}));
+            Ptr = Ptr.getBase();
+            continue;
+          }
+          llvm_unreachable("Invalid field type");
+        }
+      }
+
+      IsOnePastEnd = isOnePastEnd();
+    }
+  }
+
+  return APValue(Base, Offset, Path, IsOnePastEnd, IsNullPtr);
+}
+
+bool Pointer::isInitialized() const {
+  assert(Pointee && "Cannot check if null pointer was initialized");
+  Descriptor *Desc = getFieldDesc();
+  if (Desc->isPrimitiveArray()) {
+    if (Pointee->IsStatic)
+      return true;
+    // Primitive array field are stored in a bitset.
+    InitMap *Map = getInitMap();
+    if (!Map)
+      return false;
+    if (Map == (InitMap *)-1)
+      return true;
+    return Map->isInitialized(getIndex());
+  } else {
+    // Field has its bit in an inline descriptor.
+    return Base == 0 || getInlineDesc()->IsInitialized;
+  }
+}
+
+void Pointer::initialize() const {
+  assert(Pointee && "Cannot initialize null pointer");
+  Descriptor *Desc = getFieldDesc();
+  if (Desc->isPrimitiveArray()) {
+    if (!Pointee->IsStatic) {
+      // Primitive array initializer.
+      InitMap *&Map = getInitMap();
+      if (Map == (InitMap *)-1)
+        return;
+      if (Map == nullptr)
+        Map = InitMap::allocate(Desc->getNumElems());
+      if (Map->initialize(getIndex())) {
+        free(Map);
+        Map = (InitMap *)-1;
+      }
+    }
+  } else {
+    // Field has its bit in an inline descriptor.
+    assert(Base != 0 && "Only composite fields can be initialised");
+    getInlineDesc()->IsInitialized = true;
+  }
+}
+
+void Pointer::activate() const {
+  // Field has its bit in an inline descriptor.
+  assert(Base != 0 && "Only composite fields can be initialised");
+  getInlineDesc()->IsActive = true;
+}
+
+void Pointer::deactivate() const {
+  // TODO: this only appears in constructors, so nothing to deactivate.
+}
+
+bool Pointer::hasSameBase(const Pointer &A, const Pointer &B) {
+  return A.Pointee == B.Pointee;
+}
+
+bool Pointer::hasSameArray(const Pointer &A, const Pointer &B) {
+  return A.Base == B.Base && A.getFieldDesc()->IsArray;
+}