[RemoveDIs][DebugInfo][NFC] Add Instruction and convenience functions to DPValue (#77896)

This patch adds a set of functions to the DPValue class that
conveniently perform some common operations, and some that replicate
existing functions on `DbgVariableIntrinsic` and its subclasses.

llvm/include/llvm/IR/DebugProgramInstruction.h

@@ -47,10 +47,12 @@
 #ifndef LLVM_IR_DEBUGPROGRAMINSTRUCTION_H
 #define LLVM_IR_DEBUGPROGRAMINSTRUCTION_H
 
-#include "llvm/ADT/ilist_node.h"
 #include "llvm/ADT/ilist.h"
+#include "llvm/ADT/ilist_node.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/IR/DebugLoc.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/SymbolTableListTraits.h"
 
 namespace llvm {
 
@@ -91,6 +93,9 @@ public:
   void removeFromParent();
   void eraseFromParent();
 
+  DPValue *getNextNode() { return &*std::next(getIterator()); }
+  DPValue *getPrevNode() { return &*std::prev(getIterator()); }
+
   using self_iterator = simple_ilist<DPValue>::iterator;
   using const_self_iterator = simple_ilist<DPValue>::const_iterator;
 
@@ -118,6 +123,17 @@ public:
   DPValue(Metadata *Location, DILocalVariable *DV, DIExpression *Expr,
           const DILocation *DI, LocationType Type = LocationType::Value);
 
+  static DPValue *createDPValue(Value *Location, DILocalVariable *DV,
+                                DIExpression *Expr, const DILocation *DI);
+  static DPValue *createDPValue(Value *Location, DILocalVariable *DV,
+                                DIExpression *Expr, const DILocation *DI,
+                                DPValue &InsertBefore);
+  static DPValue *createDPVDeclare(Value *Address, DILocalVariable *DV,
+                                   DIExpression *Expr, const DILocation *DI);
+  static DPValue *createDPVDeclare(Value *Address, DILocalVariable *DV,
+                                   DIExpression *Expr, const DILocation *DI,
+                                   DPValue &InsertBefore);
+
   /// Iterator for ValueAsMetadata that internally uses direct pointer iteration
   /// over either a ValueAsMetadata* or a ValueAsMetadata**, dereferencing to the
   /// ValueAsMetadata .
@@ -166,6 +182,9 @@ public:
     }
   };
 
+  bool isDbgDeclare() { return Type == LocationType::Declare; }
+  bool isDbgValue() { return Type == LocationType::Value; }
+
   /// Get the locations corresponding to the variable referenced by the debug
   /// info intrinsic.  Depending on the intrinsic, this could be the
   /// variable's value or its address.
@@ -209,6 +228,10 @@ public:
 
   Metadata *getRawLocation() const { return DebugValue; }
 
+  Value *getValue(unsigned OpIdx = 0) const {
+    return getVariableLocationOp(OpIdx);
+  }
+
   /// Use of this should generally be avoided; instead,
   /// replaceVariableLocationOp and addVariableLocationOps should be used where
   /// possible to avoid creating invalid state.
@@ -224,6 +247,19 @@ public:
   /// is described.
   std::optional<uint64_t> getFragmentSizeInBits() const;
 
+  bool isEquivalentTo(const DPValue &Other) {
+    return std::tie(Type, DebugValue, Variable, Expression, DbgLoc) ==
+           std::tie(Other.Type, Other.DebugValue, Other.Variable,
+                    Other.Expression, Other.DbgLoc);
+  }
+  // Matches the definition of the Instruction version, equivalent to above but
+  // without checking DbgLoc.
+  bool isIdenticalToWhenDefined(const DPValue &Other) {
+    return std::tie(Type, DebugValue, Variable, Expression) ==
+           std::tie(Other.Type, Other.DebugValue, Other.Variable,
+                    Other.Expression);
+  }
+
   DPValue *clone() const;
   /// Convert this DPValue back into a dbg.value intrinsic.
   /// \p InsertBefore Optional position to insert this intrinsic.
@@ -251,6 +287,13 @@ public:
   LLVMContext &getContext();
   const LLVMContext &getContext() const;
 
+  /// Insert this DPValue prior to \p InsertBefore. Must not be called if this
+  /// is already contained in a DPMarker.
+  void insertBefore(DPValue *InsertBefore);
+  void insertAfter(DPValue *InsertAfter);
+  void moveBefore(DPValue *MoveBefore);
+  void moveAfter(DPValue *MoveAfter);
+
   void print(raw_ostream &O, bool IsForDebug = false) const;
   void print(raw_ostream &ROS, ModuleSlotTracker &MST, bool IsForDebug) const;
 };
@@ -309,6 +352,8 @@ public:
 
   /// Produce a range over all the DPValues in this Marker.
   iterator_range<simple_ilist<DPValue>::iterator> getDbgValueRange();
+  iterator_range<simple_ilist<DPValue>::const_iterator>
+  getDbgValueRange() const;
   /// Transfer any DPValues from \p Src into this DPMarker. If \p InsertAtHead
   /// is true, place them before existing DPValues, otherwise afterwards.
   void absorbDebugValues(DPMarker &Src, bool InsertAtHead);
@@ -320,6 +365,10 @@ public:
   /// Insert a DPValue into this DPMarker, at the end of the list. If
   /// \p InsertAtHead is true, at the start.
   void insertDPValue(DPValue *New, bool InsertAtHead);
+  /// Insert a DPValue prior to a DPValue contained within this marker.
+  void insertDPValue(DPValue *New, DPValue *InsertBefore);
+  /// Insert a DPValue after a DPValue contained within this marker.
+  void insertDPValueAfter(DPValue *New, DPValue *InsertAfter);
   /// Clone all DPMarkers from \p From into this marker. There are numerous
   /// options to customise the source/destination, due to gnarliness, see class
   /// comment.

llvm/lib/IR/DebugProgramInstruction.cpp

@@ -41,6 +41,34 @@ DPValue::DPValue(Metadata *Location, DILocalVariable *DV, DIExpression *Expr,
 
 void DPValue::deleteInstr() { delete this; }
 
+DPValue *DPValue::createDPValue(Value *Location, DILocalVariable *DV,
+                                DIExpression *Expr, const DILocation *DI) {
+  return new DPValue(ValueAsMetadata::get(Location), DV, Expr, DI,
+                     LocationType::Value);
+}
+
+DPValue *DPValue::createDPValue(Value *Location, DILocalVariable *DV,
+                                DIExpression *Expr, const DILocation *DI,
+                                DPValue &InsertBefore) {
+  auto *NewDPValue = createDPValue(Location, DV, Expr, DI);
+  NewDPValue->insertBefore(&InsertBefore);
+  return NewDPValue;
+}
+
+DPValue *DPValue::createDPVDeclare(Value *Address, DILocalVariable *DV,
+                                   DIExpression *Expr, const DILocation *DI) {
+  return new DPValue(ValueAsMetadata::get(Address), DV, Expr, DI,
+                     LocationType::Declare);
+}
+
+DPValue *DPValue::createDPVDeclare(Value *Address, DILocalVariable *DV,
+                                   DIExpression *Expr, const DILocation *DI,
+                                   DPValue &InsertBefore) {
+  auto *NewDPVDeclare = createDPVDeclare(Address, DV, Expr, DI);
+  NewDPVDeclare->insertBefore(&InsertBefore);
+  return NewDPVDeclare;
+}
+
 iterator_range<DPValue::location_op_iterator> DPValue::location_ops() const {
   auto *MD = getRawLocation();
   // If a Value has been deleted, the "location" for this DPValue will be
@@ -249,6 +277,35 @@ const LLVMContext &DPValue::getContext() const {
   return getBlock()->getContext();
 }
 
+void DPValue::insertBefore(DPValue *InsertBefore) {
+  assert(!getMarker() &&
+         "Cannot insert a DPValue that is already has a DPMarker!");
+  assert(InsertBefore->getMarker() &&
+         "Cannot insert a DPValue before a DPValue that does not have a "
+         "DPMarker!");
+  InsertBefore->getMarker()->insertDPValue(this, InsertBefore);
+}
+void DPValue::insertAfter(DPValue *InsertAfter) {
+  assert(!getMarker() &&
+         "Cannot insert a DPValue that is already has a DPMarker!");
+  assert(InsertAfter->getMarker() &&
+         "Cannot insert a DPValue after a DPValue that does not have a "
+         "DPMarker!");
+  InsertAfter->getMarker()->insertDPValueAfter(this, InsertAfter);
+}
+void DPValue::moveBefore(DPValue *MoveBefore) {
+  assert(getMarker() &&
+         "Canot move a DPValue that does not currently have a DPMarker!");
+  removeFromParent();
+  insertBefore(MoveBefore);
+}
+void DPValue::moveAfter(DPValue *MoveAfter) {
+  assert(getMarker() &&
+         "Canot move a DPValue that does not currently have a DPMarker!");
+  removeFromParent();
+  insertAfter(MoveAfter);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 // An empty, global, DPMarker for the purpose of describing empty ranges of
@@ -313,9 +370,14 @@ void DPMarker::eraseFromParent() {
 iterator_range<DPValue::self_iterator> DPMarker::getDbgValueRange() {
   return make_range(StoredDPValues.begin(), StoredDPValues.end());
 }
+iterator_range<DPValue::const_self_iterator>
+DPMarker::getDbgValueRange() const {
+  return make_range(StoredDPValues.begin(), StoredDPValues.end());
+}
 
 void DPValue::removeFromParent() {
   getMarker()->StoredDPValues.erase(getIterator());
+  Marker = nullptr;
 }
 
 void DPValue::eraseFromParent() {
@@ -328,6 +390,18 @@ void DPMarker::insertDPValue(DPValue *New, bool InsertAtHead) {
   StoredDPValues.insert(It, *New);
   New->setMarker(this);
 }
+void DPMarker::insertDPValue(DPValue *New, DPValue *InsertBefore) {
+  assert(InsertBefore->getMarker() == this &&
+         "DPValue 'InsertBefore' must be contained in this DPMarker!");
+  StoredDPValues.insert(InsertBefore->getIterator(), *New);
+  New->setMarker(this);
+}
+void DPMarker::insertDPValueAfter(DPValue *New, DPValue *InsertAfter) {
+  assert(InsertAfter->getMarker() == this &&
+         "DPValue 'InsertAfter' must be contained in this DPMarker!");
+  StoredDPValues.insert(++(InsertAfter->getIterator()), *New);
+  New->setMarker(this);
+}
 
 void DPMarker::absorbDebugValues(DPMarker &Src, bool InsertAtHead) {
   auto It = InsertAtHead ? StoredDPValues.begin() : StoredDPValues.end();