1 //===-- PdbFPOProgramToDWARFExpression.cpp --------------------------------===//
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 "PdbFPOProgramToDWARFExpression.h"
10 #include "CodeViewRegisterMapping.h"
11 
12 #include "lldb/Core/StreamBuffer.h"
13 #include "lldb/Symbol/PostfixExpression.h"
14 #include "lldb/Utility/LLDBAssert.h"
15 #include "lldb/Utility/Stream.h"
16 #include "llvm/ADT/DenseMap.h"
17 
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/DebugInfo/CodeView/CodeView.h"
20 #include "llvm/DebugInfo/CodeView/EnumTables.h"
21 
22 using namespace lldb;
23 using namespace lldb_private;
24 using namespace lldb_private::postfix;
25 
26 static uint32_t ResolveLLDBRegisterNum(llvm::StringRef reg_name, llvm::Triple::ArchType arch_type) {
27   // lookup register name to get lldb register number
28   llvm::codeview::CPUType cpu_type;
29   switch (arch_type) {
30     case llvm::Triple::ArchType::aarch64:
31       cpu_type = llvm::codeview::CPUType::ARM64;
32       break;
33 
34     default:
35       cpu_type = llvm::codeview::CPUType::X64;
36       break;
37   }
38 
39   llvm::ArrayRef<llvm::EnumEntry<uint16_t>> register_names =
40       llvm::codeview::getRegisterNames(cpu_type);
41   auto it = llvm::find_if(
42       register_names,
43       [&reg_name](const llvm::EnumEntry<uint16_t> &register_entry) {
44         return reg_name.compare_insensitive(register_entry.Name) == 0;
45       });
46 
47   if (it == register_names.end())
48     return LLDB_INVALID_REGNUM;
49 
50   auto reg_id = static_cast<llvm::codeview::RegisterId>(it->Value);
51   return npdb::GetLLDBRegisterNumber(arch_type, reg_id);
52 }
53 
54 static Node *ResolveFPOProgram(llvm::StringRef program,
55                              llvm::StringRef register_name,
56                              llvm::Triple::ArchType arch_type,
57                              llvm::BumpPtrAllocator &alloc) {
58   std::vector<std::pair<llvm::StringRef, Node *>> parsed =
59       postfix::ParseFPOProgram(program, alloc);
60 
61   for (auto it = parsed.begin(), end = parsed.end(); it != end; ++it) {
62     // Emplace valid dependent subtrees to make target assignment independent
63     // from predecessors. Resolve all other SymbolNodes as registers.
64     bool success =
65         ResolveSymbols(it->second, [&](SymbolNode &symbol) -> Node * {
66           for (const auto &pair : llvm::make_range(parsed.begin(), it)) {
67             if (pair.first == symbol.GetName())
68               return pair.second;
69           }
70 
71           uint32_t reg_num =
72               ResolveLLDBRegisterNum(symbol.GetName().drop_front(1), arch_type);
73 
74           if (reg_num == LLDB_INVALID_REGNUM)
75             return nullptr;
76 
77           return MakeNode<RegisterNode>(alloc, reg_num);
78         });
79     if (!success)
80       return nullptr;
81 
82     if (it->first == register_name) {
83       // found target assignment program - no need to parse further
84       return it->second;
85     }
86   }
87 
88   return nullptr;
89 }
90 
91 bool lldb_private::npdb::TranslateFPOProgramToDWARFExpression(
92     llvm::StringRef program, llvm::StringRef register_name,
93     llvm::Triple::ArchType arch_type, Stream &stream) {
94   llvm::BumpPtrAllocator node_alloc;
95   Node *target_program =
96       ResolveFPOProgram(program, register_name, arch_type, node_alloc);
97   if (target_program == nullptr) {
98     return false;
99   }
100 
101   ToDWARF(*target_program, stream);
102   return true;
103 }
104