[llvm] [SandboxVec] Implement Pass class (PR #107617)

[via llvm-commits]

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+//===- Pass.h ---------------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SANDBOXIR_PASS_H
+#define LLVM_SANDBOXIR_PASS_H
+
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm::sandboxir {
+
+class Function;
+
+/// The base class of a Sandbox IR Pass.
+class Pass {
+public:
+  enum class ClassID : unsigned {
+    FunctionPass,
+  };
+  static const char *getSubclassIDStr(ClassID ID) {
+    switch (ID) {
+    case ClassID::FunctionPass:
+      return "FunctionPass";
+    }
+    llvm_unreachable("Unimplemented ID");
+  }
+
+protected:
+  /// The pass name.
+  const std::string Name;
+  /// The command-line flag used to specify that this pass should run.
+  const std::string Flag;
+  /// Used for isa/cast/dyn_cast.
+  ClassID SubclassID;
+
+public:
+  Pass(StringRef Name, StringRef Flag, ClassID SubclassID)
+      : Name(Name), Flag(Flag), SubclassID(SubclassID) {}
+  virtual ~Pass() {}
+  /// \Returns the name of the pass.
+  StringRef getName() const { return Name; }
+  /// \Returns the command-line flag used to enable the pass.
+  StringRef getFlag() const { return Flag; }
+  ClassID getSubclassID() const { return SubclassID; }
+#ifndef NDEBUG
+  friend raw_ostream &operator<<(raw_ostream &OS, const Pass &Pass) {
+    Pass.dumpOS(OS);
+    return OS;
+  }
+  void dumpOS(raw_ostream &OS) const { OS << Name << " " << Flag; }
+  LLVM_DUMP_METHOD void dump() const;
+#endif
+};
+
+/// A pass that runs on a sandbox::Function.
+class FunctionPass : public Pass {
+protected:
+  FunctionPass(StringRef Name, StringRef Flag, ClassID PassID)
+      : Pass(Name, Flag, PassID) {}
+
+public:
+  FunctionPass(StringRef Name, StringRef Flag)
+      : Pass(Name, Flag, ClassID::FunctionPass) {}
+  /// For isa/dyn_cast etc.
+  static bool classof(const Pass *From) {
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vporpo wrote:

Our pass manager will operate in a similar way: The top-level pass manager will visit the functions in some order and for each one of them it will call `runOnFunction()` for all registered passes before moving to the next function. The pass order is fixed. One or more function passes will also be a Region pass manager and that will operate in a similar way: it will go over the regions and for each one of them will call `runOnRegion()` for all registered region passes.

We could use a virtual `run()` but if we want to keep the `runOnFunction/Region()` names I think we need the `isa/dyn_cast` stuff.

https://github.com/llvm/llvm-project/pull/107617