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(nullptr), m_passthrough(passthrough),
33       m_passthrough_sema(nullptr), m_sema(nullptr), 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 
41 ASTStructExtractor::~ASTStructExtractor() {}
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 = nullptr;
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 
132 bool ASTStructExtractor::HandleTopLevelDecl(DeclGroupRef D) {
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 
146 void ASTStructExtractor::HandleTranslationUnit(ASTContext &Ctx) {
147   if (m_passthrough)
148     m_passthrough->HandleTranslationUnit(Ctx);
149 }
150 
151 void ASTStructExtractor::HandleTagDeclDefinition(TagDecl *D) {
152   if (m_passthrough)
153     m_passthrough->HandleTagDeclDefinition(D);
154 }
155 
156 void ASTStructExtractor::CompleteTentativeDefinition(VarDecl *D) {
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 
166 void ASTStructExtractor::PrintStats() {
167   if (m_passthrough)
168     m_passthrough->PrintStats();
169 }
170 
171 void ASTStructExtractor::InitializeSema(Sema &S) {
172   m_sema = &S;
173 
174   if (m_passthrough_sema)
175     m_passthrough_sema->InitializeSema(S);
176 }
177 
178 void ASTStructExtractor::ForgetSema() {
179   m_sema = nullptr;
180 
181   if (m_passthrough_sema)
182     m_passthrough_sema->ForgetSema();
183 }
184