1 files changed, 110 insertions, 0 deletions
diff --git a/include/llvm/CodeGen/SwiftErrorValueTracking.h b/include/llvm/CodeGen/SwiftErrorValueTracking.h
new file mode 100644
index 000000000000..fb7a12853c09
--- /dev/null
+++ b/include/llvm/CodeGen/SwiftErrorValueTracking.h
@@ -0,0 +1,110 @@
+//===- SwiftErrorValueTracking.h - Track swifterror VReg vals --*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements a limited mem2reg-like analysis to promote uses of function
+// arguments and allocas marked with swiftalloc from memory into virtual
+// registers tracked by this class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFTERRORVALUETRACKING_H
+#define SWIFTERRORVALUETRACKING_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/Register.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/DebugLoc.h"
+#include <functional>
+#include <type_traits>
+#include <utility>
+
+
+namespace llvm {
+  class Function;
+  class MachineBasicBlock;
+  class MachineFunction;
+  class MachineInstr;
+  class TargetInstrInfo;
+  class TargetLowering;
+
+class SwiftErrorValueTracking {
+  // Some useful objects to reduce the number of function arguments needed.
+  MachineFunction *MF;
+  const Function *Fn;
+  const TargetLowering *TLI;
+  const TargetInstrInfo *TII;
+
+  /// A map from swifterror value in a basic block to the virtual register it is
+  /// currently represented by.
+  DenseMap<std::pair<const MachineBasicBlock *, const Value *>, Register>
+      VRegDefMap;
+
+  /// A list of upward exposed vreg uses that need to be satisfied by either a
+  /// copy def or a phi node at the beginning of the basic block representing
+  /// the predecessor(s) swifterror value.
+  DenseMap<std::pair<const MachineBasicBlock *, const Value *>, Register>
+      VRegUpwardsUse;
+
+  /// A map from instructions that define/use a swifterror value to the virtual
+  /// register that represents that def/use.
+  llvm::DenseMap<PointerIntPair<const Instruction *, 1, bool>, Register>
+      VRegDefUses;
+
+  /// The swifterror argument of the current function.
+  const Value *SwiftErrorArg;
+
+  using SwiftErrorValues = SmallVector<const Value*, 1>;
+  /// A function can only have a single swifterror argument. And if it does
+  /// have a swifterror argument, it must be the first entry in
+  /// SwiftErrorVals.
+  SwiftErrorValues SwiftErrorVals;
+
+public:
+  /// Initialize data structures for specified new function.
+  void setFunction(MachineFunction &MF);
+
+  /// Get the (unique) function argument that was marked swifterror, or nullptr
+  /// if this function has no swifterror args.
+  const Value *getFunctionArg() const {
+    return SwiftErrorArg;
+  }
+
+  /// Get or create the swifterror value virtual register in
+  /// VRegDefMap for this basic block.
+  Register getOrCreateVReg(const MachineBasicBlock *, const Value *);
+
+  /// Set the swifterror virtual register in the VRegDefMap for this
+  /// basic block.
+  void setCurrentVReg(const MachineBasicBlock *MBB, const Value *, Register);
+
+  /// Get or create the swifterror value virtual register for a def of a
+  /// swifterror by an instruction.
+  Register getOrCreateVRegDefAt(const Instruction *, const MachineBasicBlock *,
+                                const Value *);
+
+  /// Get or create the swifterror value virtual register for a use of a
+  /// swifterror by an instruction.
+  Register getOrCreateVRegUseAt(const Instruction *, const MachineBasicBlock *,
+                                const Value *);
+
+  /// Create initial definitions of swifterror values in the entry block of the
+  /// current function.
+  bool createEntriesInEntryBlock(DebugLoc DbgLoc);
+
+  /// Propagate assigned swifterror vregs through a function, synthesizing PHI
+  /// nodes when needed to maintain consistency.
+  void propagateVRegs();
+
+  void preassignVRegs(MachineBasicBlock *MBB, BasicBlock::const_iterator Begin,
+                      BasicBlock::const_iterator End);
+};
+
+}
+
+#endif