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ASTStructExtractor.cpp
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1 //===-- ASTStructExtractor.cpp ----------------------------------*- 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 #include "ASTStructExtractor.h"
10 
11 #include "lldb/Utility/Log.h"
12 #include "stdlib.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/Decl.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/AST/DeclGroup.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/RecordLayout.h"
19 #include "clang/AST/Stmt.h"
20 #include "clang/Parse/Parser.h"
21 #include "clang/Sema/Sema.h"
22 #include "llvm/Support/Casting.h"
23 #include "llvm/Support/raw_ostream.h"
24 
25 using namespace llvm;
26 using namespace clang;
27 using namespace lldb_private;
28 
29 ASTStructExtractor::ASTStructExtractor(ASTConsumer *passthrough,
30  const char *struct_name,
31  ClangFunctionCaller &function)
32  : m_ast_context(NULL), m_passthrough(passthrough), m_passthrough_sema(NULL),
33  m_sema(NULL), m_action(NULL), m_function(function),
34  m_struct_name(struct_name) {
35  if (!m_passthrough)
36  return;
37 
38  m_passthrough_sema = dyn_cast<SemaConsumer>(passthrough);
39 }
40 
42 
43 void ASTStructExtractor::Initialize(ASTContext &Context) {
44  m_ast_context = &Context;
45 
46  if (m_passthrough)
47  m_passthrough->Initialize(Context);
48 }
49 
50 void ASTStructExtractor::ExtractFromFunctionDecl(FunctionDecl *F) {
51  if (!F->hasBody())
52  return;
53 
54  Stmt *body_stmt = F->getBody();
55  CompoundStmt *body_compound_stmt = dyn_cast<CompoundStmt>(body_stmt);
56 
57  if (!body_compound_stmt)
58  return; // do we have to handle this?
59 
60  RecordDecl *struct_decl = NULL;
61 
62  StringRef desired_name(m_struct_name);
63 
64  for (CompoundStmt::const_body_iterator bi = body_compound_stmt->body_begin(),
65  be = body_compound_stmt->body_end();
66  bi != be; ++bi) {
67  Stmt *curr_stmt = *bi;
68  DeclStmt *curr_decl_stmt = dyn_cast<DeclStmt>(curr_stmt);
69  if (!curr_decl_stmt)
70  continue;
71  DeclGroupRef decl_group = curr_decl_stmt->getDeclGroup();
72  for (Decl *candidate_decl : decl_group) {
73  RecordDecl *candidate_record_decl = dyn_cast<RecordDecl>(candidate_decl);
74  if (!candidate_record_decl)
75  continue;
76  if (candidate_record_decl->getName() == desired_name) {
77  struct_decl = candidate_record_decl;
78  break;
79  }
80  }
81  if (struct_decl)
82  break;
83  }
84 
85  if (!struct_decl)
86  return;
87 
88  const ASTRecordLayout *struct_layout(
89  &m_ast_context->getASTRecordLayout(struct_decl));
90 
91  if (!struct_layout)
92  return;
93 
94  m_function.m_struct_size =
95  struct_layout->getSize()
96  .getQuantity(); // TODO Store m_struct_size as CharUnits
97  m_function.m_return_offset =
98  struct_layout->getFieldOffset(struct_layout->getFieldCount() - 1) / 8;
99  m_function.m_return_size =
100  struct_layout->getDataSize().getQuantity() - m_function.m_return_offset;
101 
102  for (unsigned field_index = 0, num_fields = struct_layout->getFieldCount();
103  field_index < num_fields; ++field_index) {
104  m_function.m_member_offsets.push_back(
105  struct_layout->getFieldOffset(field_index) / 8);
106  }
107 
108  m_function.m_struct_valid = true;
109 }
110 
111 void ASTStructExtractor::ExtractFromTopLevelDecl(Decl *D) {
112  LinkageSpecDecl *linkage_spec_decl = dyn_cast<LinkageSpecDecl>(D);
113 
114  if (linkage_spec_decl) {
115  RecordDecl::decl_iterator decl_iterator;
116 
117  for (decl_iterator = linkage_spec_decl->decls_begin();
118  decl_iterator != linkage_spec_decl->decls_end(); ++decl_iterator) {
119  ExtractFromTopLevelDecl(*decl_iterator);
120  }
121  }
122 
123  FunctionDecl *function_decl = dyn_cast<FunctionDecl>(D);
124 
125  if (m_ast_context && function_decl &&
126  !m_function.m_wrapper_function_name.compare(
127  function_decl->getNameAsString())) {
128  ExtractFromFunctionDecl(function_decl);
129  }
130 }
131 
133  DeclGroupRef::iterator decl_iterator;
134 
135  for (decl_iterator = D.begin(); decl_iterator != D.end(); ++decl_iterator) {
136  Decl *decl = *decl_iterator;
137 
138  ExtractFromTopLevelDecl(decl);
139  }
140 
141  if (m_passthrough)
142  return m_passthrough->HandleTopLevelDecl(D);
143  return true;
144 }
145 
147  if (m_passthrough)
148  m_passthrough->HandleTranslationUnit(Ctx);
149 }
150 
152  if (m_passthrough)
153  m_passthrough->HandleTagDeclDefinition(D);
154 }
155 
157  if (m_passthrough)
158  m_passthrough->CompleteTentativeDefinition(D);
159 }
160 
161 void ASTStructExtractor::HandleVTable(CXXRecordDecl *RD) {
162  if (m_passthrough)
163  m_passthrough->HandleVTable(RD);
164 }
165 
167  if (m_passthrough)
168  m_passthrough->PrintStats();
169 }
170 
172  m_sema = &S;
173  m_action = reinterpret_cast<Action *>(m_sema);
174 
175  if (m_passthrough_sema)
176  m_passthrough_sema->InitializeSema(S);
177 }
178 
180  m_sema = NULL;
181  m_action = NULL;
182 
183  if (m_passthrough_sema)
184  m_passthrough_sema->ForgetSema();
185 }
Enumerations for broadcasting.
Definition: SBLaunchInfo.h:14
Definition: Debugger.h:71
size_t m_struct_size
These values are populated by the ASTStructExtractor.
void PrintStats() override
Passthrough stub.
void HandleTagDeclDefinition(clang::TagDecl *D) override
Passthrough stub.
void Initialize(clang::ASTContext &Context) override
Link this consumer with a particular AST context.
std::string m_wrapper_function_name
The name of the wrapper function.
uint64_t m_return_size
The size of the result variable, in bytes.
bool HandleTopLevelDecl(clang::DeclGroupRef D) override
Examine a list of Decls to find the function $__lldb_expr and transform its code. ...
std::vector< uint64_t > m_member_offsets
The offset of each member in the struct, in bytes.
~ASTStructExtractor() override
Destructor.
void HandleTranslationUnit(clang::ASTContext &Ctx) override
Passthrough stub.
"lldb/Expression/ClangFunctionCaller.h" Encapsulates a function that can be called.
void ForgetSema() override
Reset the Sema to NULL now that transformations are done.
void CompleteTentativeDefinition(clang::VarDecl *D) override
Passthrough stub.
void InitializeSema(clang::Sema &S) override
Set the Sema object to use when performing transforms, and pass it on.
void HandleVTable(clang::CXXRecordDecl *RD) override
Passthrough stub.
uint64_t m_return_offset
The offset of the result variable in the struct, in bytes.
bool m_struct_valid
True if the ASTStructExtractor has populated the variables below.