1 //===- DebugInfo.h - Debug Information Helpers ------------------*- 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 // This file defines a bunch of datatypes that are useful for creating and
10 // walking debug info in LLVM IR form. They essentially provide wrappers around
11 // the information in the global variables that's needed when constructing the
12 // DWARF information.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_IR_DEBUGINFO_H
17 #define LLVM_IR_DEBUGINFO_H
18 
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SmallPtrSet.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/TinyPtrVector.h"
23 #include "llvm/ADT/iterator_range.h"
24 #include "llvm/IR/DebugInfoMetadata.h"
25 
26 namespace llvm {
27 
28 class DbgDeclareInst;
29 class DbgValueInst;
30 class DbgVariableIntrinsic;
31 class Instruction;
32 class Module;
33 
34 /// Finds all intrinsics declaring local variables as living in the memory that
35 /// 'V' points to. This may include a mix of dbg.declare and
36 /// dbg.addr intrinsics.
37 TinyPtrVector<DbgVariableIntrinsic *> FindDbgAddrUses(Value *V);
38 
39 /// Like \c FindDbgAddrUses, but only returns dbg.declare intrinsics, not
40 /// dbg.addr.
41 TinyPtrVector<DbgDeclareInst *> FindDbgDeclareUses(Value *V);
42 
43 /// Finds the llvm.dbg.value intrinsics describing a value.
44 void findDbgValues(SmallVectorImpl<DbgValueInst *> &DbgValues, Value *V);
45 
46 /// Finds the debug info intrinsics describing a value.
47 void findDbgUsers(SmallVectorImpl<DbgVariableIntrinsic *> &DbgInsts, Value *V);
48 
49 /// Find subprogram that is enclosing this scope.
50 DISubprogram *getDISubprogram(const MDNode *Scope);
51 
52 /// Strip debug info in the module if it exists.
53 ///
54 /// To do this, we remove all calls to the debugger intrinsics and any named
55 /// metadata for debugging. We also remove debug locations for instructions.
56 /// Return true if module is modified.
57 bool StripDebugInfo(Module &M);
58 bool stripDebugInfo(Function &F);
59 
60 /// Downgrade the debug info in a module to contain only line table information.
61 ///
62 /// In order to convert debug info to what -gline-tables-only would have
63 /// created, this does the following:
64 ///   1) Delete all debug intrinsics.
65 ///   2) Delete all non-CU named metadata debug info nodes.
66 ///   3) Create new DebugLocs for each instruction.
67 ///   4) Create a new CU debug info, and similarly for every metadata node
68 ///      that's reachable from the CU debug info.
69 ///   All debug type metadata nodes are unreachable and garbage collected.
70 bool stripNonLineTableDebugInfo(Module &M);
71 
72 /// Update the debug locations contained within the MD_loop metadata attached
73 /// to the instruction \p I, if one exists. \p Updater is applied to Metadata
74 /// operand in the MD_loop metadata: the returned value is included in the
75 /// updated loop metadata node if it is non-null.
76 void updateLoopMetadataDebugLocations(
77     Instruction &I, function_ref<Metadata *(Metadata *)> Updater);
78 
79 /// Return Debug Info Metadata Version by checking module flags.
80 unsigned getDebugMetadataVersionFromModule(const Module &M);
81 
82 /// Utility to find all debug info in a module.
83 ///
84 /// DebugInfoFinder tries to list all debug info MDNodes used in a module. To
85 /// list debug info MDNodes used by an instruction, DebugInfoFinder uses
86 /// processDeclare, processValue and processLocation to handle DbgDeclareInst,
87 /// DbgValueInst and DbgLoc attached to instructions. processModule will go
88 /// through all DICompileUnits in llvm.dbg.cu and list debug info MDNodes
89 /// used by the CUs.
90 class DebugInfoFinder {
91 public:
92   /// Process entire module and collect debug info anchors.
93   void processModule(const Module &M);
94   /// Process a single instruction and collect debug info anchors.
95   void processInstruction(const Module &M, const Instruction &I);
96 
97   /// Process DbgVariableIntrinsic.
98   void processVariable(const Module &M, const DbgVariableIntrinsic &DVI);
99   /// Process debug info location.
100   void processLocation(const Module &M, const DILocation *Loc);
101 
102   /// Process subprogram.
103   void processSubprogram(DISubprogram *SP);
104 
105   /// Clear all lists.
106   void reset();
107 
108 private:
109   void processCompileUnit(DICompileUnit *CU);
110   void processScope(DIScope *Scope);
111   void processType(DIType *DT);
112   bool addCompileUnit(DICompileUnit *CU);
113   bool addGlobalVariable(DIGlobalVariableExpression *DIG);
114   bool addScope(DIScope *Scope);
115   bool addSubprogram(DISubprogram *SP);
116   bool addType(DIType *DT);
117 
118 public:
119   using compile_unit_iterator =
120       SmallVectorImpl<DICompileUnit *>::const_iterator;
121   using subprogram_iterator = SmallVectorImpl<DISubprogram *>::const_iterator;
122   using global_variable_expression_iterator =
123       SmallVectorImpl<DIGlobalVariableExpression *>::const_iterator;
124   using type_iterator = SmallVectorImpl<DIType *>::const_iterator;
125   using scope_iterator = SmallVectorImpl<DIScope *>::const_iterator;
126 
127   iterator_range<compile_unit_iterator> compile_units() const {
128     return make_range(CUs.begin(), CUs.end());
129   }
130 
131   iterator_range<subprogram_iterator> subprograms() const {
132     return make_range(SPs.begin(), SPs.end());
133   }
134 
135   iterator_range<global_variable_expression_iterator> global_variables() const {
136     return make_range(GVs.begin(), GVs.end());
137   }
138 
139   iterator_range<type_iterator> types() const {
140     return make_range(TYs.begin(), TYs.end());
141   }
142 
143   iterator_range<scope_iterator> scopes() const {
144     return make_range(Scopes.begin(), Scopes.end());
145   }
146 
147   unsigned compile_unit_count() const { return CUs.size(); }
148   unsigned global_variable_count() const { return GVs.size(); }
149   unsigned subprogram_count() const { return SPs.size(); }
150   unsigned type_count() const { return TYs.size(); }
151   unsigned scope_count() const { return Scopes.size(); }
152 
153 private:
154   SmallVector<DICompileUnit *, 8> CUs;
155   SmallVector<DISubprogram *, 8> SPs;
156   SmallVector<DIGlobalVariableExpression *, 8> GVs;
157   SmallVector<DIType *, 8> TYs;
158   SmallVector<DIScope *, 8> Scopes;
159   SmallPtrSet<const MDNode *, 32> NodesSeen;
160 };
161 
162 } // end namespace llvm
163 
164 #endif // LLVM_IR_DEBUGINFO_H
165