1 //===-- Bitcode/Reader/MetadataLoader.h - Load Metadatas -------*- C++ -*-====//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This class handles loading Metadatas.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_BITCODE_READER_METADATALOADER_H
15 #define LLVM_LIB_BITCODE_READER_METADATALOADER_H
16 
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/Support/Error.h"
19 
20 #include <functional>
21 #include <memory>
22 
23 namespace llvm {
24 class BitcodeReaderValueList;
25 class BitstreamCursor;
26 class DISubprogram;
27 class Error;
28 class Function;
29 class Instruction;
30 class Metadata;
31 class MDNode;
32 class Module;
33 class Type;
34 
35 /// Helper class that handles loading Metadatas and keeping them available.
36 class MetadataLoader {
37   class MetadataLoaderImpl;
38   std::unique_ptr<MetadataLoaderImpl> Pimpl;
39   /// True if metadata is being parsed for a module being ThinLTO imported.
40   bool IsImporting = false;
41   Error parseMetadata(bool ModuleLevel);
42 
43 public:
44   ~MetadataLoader();
45   MetadataLoader(BitstreamCursor &Stream, Module &TheModule,
46                  BitcodeReaderValueList &ValueList, bool IsImporting,
47                  std::function<Type *(unsigned)> getTypeByID);
48   MetadataLoader &operator=(MetadataLoader &&);
49   MetadataLoader(MetadataLoader &&);
50 
51   // Parse a module metadata block
52   Error parseModuleMetadata() { return parseMetadata(true); }
53 
54   // Parse a function metadata block
55   Error parseFunctionMetadata() { return parseMetadata(false); }
56 
57   /// Set the mode to strip TBAA metadata on load.
58   void setStripTBAA(bool StripTBAA = true);
59 
60   /// Return true if the Loader is stripping TBAA metadata.
61   bool isStrippingTBAA();
62 
63   // Return true there are remaining unresolved forward references.
64   bool hasFwdRefs() const;
65 
66   /// Return the given metadata, creating a replaceable forward reference if
67   /// necessary.
68   Metadata *getMetadataFwdRef(unsigned Idx);
69 
70   MDNode *getMDNodeFwdRefOrNull(unsigned Idx);
71 
72   /// Return the DISubprogra metadata for a Function if any, null otherwise.
73   DISubprogram *lookupSubprogramForFunction(Function *F);
74 
75   /// Parse a `METADATA_ATTACHMENT` block for a function.
76   Error parseMetadataAttachment(
77       Function &F, const SmallVectorImpl<Instruction *> &InstructionList);
78 
79   /// Parse a `METADATA_KIND` block for the current module.
80   Error parseMetadataKinds();
81 
82   unsigned size() const;
83   void shrinkTo(unsigned N);
84 };
85 }
86 
87 #endif // LLVM_LIB_BITCODE_READER_METADATALOADER_H
88