1 //===--- Source.h - Source location provider for the VM  --------*- 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 // Defines a program which organises and links multiple bytecode functions.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_INTERP_SOURCE_H
14 #define LLVM_CLANG_AST_INTERP_SOURCE_H
15 
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/Stmt.h"
18 #include "llvm/Support/Endian.h"
19 
20 namespace clang {
21 namespace interp {
22 class Function;
23 
24 /// Pointer into the code segment.
25 class CodePtr {
26 public:
27   CodePtr() : Ptr(nullptr) {}
28 
29   CodePtr &operator+=(int32_t Offset) {
30     Ptr += Offset;
31     return *this;
32   }
33 
34   int32_t operator-(const CodePtr &RHS) const {
35     assert(Ptr != nullptr && RHS.Ptr != nullptr && "Invalid code pointer");
36     return Ptr - RHS.Ptr;
37   }
38 
39   CodePtr operator-(size_t RHS) const {
40     assert(Ptr != nullptr && "Invalid code pointer");
41     return CodePtr(Ptr - RHS);
42   }
43 
44   bool operator!=(const CodePtr &RHS) const { return Ptr != RHS.Ptr; }
45 
46   /// Reads data and advances the pointer.
47   template <typename T> std::enable_if_t<!std::is_pointer<T>::value, T> read() {
48     using namespace llvm::support;
49     T Value = endian::read<T, endianness::native, 1>(Ptr);
50     Ptr += sizeof(T);
51     return Value;
52   }
53 
54 private:
55   /// Constructor used by Function to generate pointers.
56   CodePtr(const char *Ptr) : Ptr(Ptr) {}
57 
58 private:
59   friend class Function;
60 
61   /// Pointer into the code owned by a function.
62   const char *Ptr;
63 };
64 
65 /// Describes the statement/declaration an opcode was generated from.
66 class SourceInfo {
67 public:
68   SourceInfo() {}
69   SourceInfo(const Stmt *E) : Source(E) {}
70   SourceInfo(const Decl *D) : Source(D) {}
71 
72   SourceLocation getLoc() const;
73 
74   const Stmt *asStmt() const { return Source.dyn_cast<const Stmt *>(); }
75   const Decl *asDecl() const { return Source.dyn_cast<const Decl *>(); }
76   const Expr *asExpr() const;
77 
78   operator bool() const { return !Source.isNull(); }
79 
80 private:
81   llvm::PointerUnion<const Decl *, const Stmt *> Source;
82 };
83 
84 using SourceMap = std::vector<std::pair<unsigned, SourceInfo>>;
85 
86 /// Interface for classes which map locations to sources.
87 class SourceMapper {
88 public:
89   virtual ~SourceMapper() {}
90 
91   /// Returns source information for a given PC in a function.
92   virtual SourceInfo getSource(Function *F, CodePtr PC) const = 0;
93 
94   /// Returns the expression if an opcode belongs to one, null otherwise.
95   const Expr *getExpr(Function *F, CodePtr PC) const;
96   /// Returns the location from which an opcode originates.
97   SourceLocation getLocation(Function *F, CodePtr PC) const;
98 };
99 
100 } // namespace interp
101 } // namespace clang
102 
103 #endif
104