1 //===- llvm/CodeGen/GCMetadataPrinter.h - Prints asm GC tables --*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // The abstract base class GCMetadataPrinter supports writing GC metadata tables
10 // as assembly code. This is a separate class from GCStrategy in order to allow
11 // users of the LLVM JIT to avoid linking with the AsmWriter.
12 //
13 // Subclasses of GCMetadataPrinter must be registered using the
14 // GCMetadataPrinterRegistry. This is separate from the GCStrategy itself
15 // because these subclasses are logically plugins for the AsmWriter.
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #ifndef LLVM_CODEGEN_GCMETADATAPRINTER_H
20 #define LLVM_CODEGEN_GCMETADATAPRINTER_H
21 
22 #include "llvm/Support/Registry.h"
23 
24 namespace llvm {
25 
26 class AsmPrinter;
27 class GCMetadataPrinter;
28 class GCModuleInfo;
29 class GCStrategy;
30 class Module;
31 class StackMaps;
32 
33 /// GCMetadataPrinterRegistry - The GC assembly printer registry uses all the
34 /// defaults from Registry.
35 using GCMetadataPrinterRegistry = Registry<GCMetadataPrinter>;
36 
37 /// GCMetadataPrinter - Emits GC metadata as assembly code.  Instances are
38 /// created, managed, and owned by the AsmPrinter.
39 class GCMetadataPrinter {
40 private:
41   friend class AsmPrinter;
42 
43   GCStrategy *S;
44 
45 protected:
46   // May only be subclassed.
47   GCMetadataPrinter();
48 
49 public:
50   GCMetadataPrinter(const GCMetadataPrinter &) = delete;
51   GCMetadataPrinter &operator=(const GCMetadataPrinter &) = delete;
52   virtual ~GCMetadataPrinter();
53 
54   GCStrategy &getStrategy() { return *S; }
55 
56   /// Called before the assembly for the module is generated by
57   /// the AsmPrinter (but after target specific hooks.)
58   virtual void beginAssembly(Module &M, GCModuleInfo &Info, AsmPrinter &AP) {}
59 
60   /// Called after the assembly for the module is generated by
61   /// the AsmPrinter (but before target specific hooks)
62   virtual void finishAssembly(Module &M, GCModuleInfo &Info, AsmPrinter &AP) {}
63 
64   /// Called when the stack maps are generated. Return true if
65   /// stack maps with a custom format are generated. Otherwise
66   /// returns false and the default format will be used.
67   virtual bool emitStackMaps(StackMaps &SM, AsmPrinter &AP) { return false; }
68 };
69 
70 } // end namespace llvm
71 
72 #endif // LLVM_CODEGEN_GCMETADATAPRINTER_H
73