contrib/llvm-project/lldb/source/Plugins/SymbolFile/NativePDB/PdbFPOProgramToDWARFExpression.cpp

   1 //===-- PdbFPOProgramToDWARFExpression.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 "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_lower(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 bool ParseFPOSingleAssignmentProgram(llvm::StringRef program,
  55                                             llvm::BumpPtrAllocator &alloc,
  56                                             llvm::StringRef &register_name,
  57                                             Node *&ast) {
  58   // lvalue of assignment is always first token
  59   // rvalue program goes next
  60   std::tie(register_name, program) = getToken(program);
  61   if (register_name.empty())
  62     return false;
  63
  64   ast = Parse(program, alloc);
  65   return ast != nullptr;
  66 }
  67
  68 static Node *ParseFPOProgram(llvm::StringRef program,
  69                              llvm::StringRef register_name,
  70                              llvm::Triple::ArchType arch_type,
  71                              llvm::BumpPtrAllocator &alloc) {
  72   llvm::DenseMap<llvm::StringRef, Node *> dependent_programs;
  73
  74   size_t cur = 0;
  75   while (true) {
  76     size_t assign_index = program.find('=', cur);
  77     if (assign_index == llvm::StringRef::npos) {
  78       llvm::StringRef tail = program.slice(cur, llvm::StringRef::npos);
  79       if (!tail.trim().empty()) {
  80         // missing assign operator
  81         return nullptr;
  82       }
  83       break;
  84     }
  85     llvm::StringRef assignment_program = program.slice(cur, assign_index);
  86
  87     llvm::StringRef lvalue_name;
  88     Node *rvalue_ast = nullptr;
  89     if (!ParseFPOSingleAssignmentProgram(assignment_program, alloc, lvalue_name,
  90                                          rvalue_ast)) {
  91       return nullptr;
  92     }
  93
  94     lldbassert(rvalue_ast);
  95
  96     // Emplace valid dependent subtrees to make target assignment independent
  97     // from predecessors. Resolve all other SymbolNodes as registers.
  98     bool success =
  99         ResolveSymbols(rvalue_ast, [&](SymbolNode &symbol) -> Node * {
 100           if (Node *node = dependent_programs.lookup(symbol.GetName()))
 101             return node;
 102           uint32_t reg_num =
 103               ResolveLLDBRegisterNum(symbol.GetName().drop_front(1), arch_type);
 104
 105           if (reg_num == LLDB_INVALID_REGNUM)
 106             return nullptr;
 107
 108           return MakeNode<RegisterNode>(alloc, reg_num);
 109         });
 110     if (!success)
 111       return nullptr;
 112
 113     if (lvalue_name == register_name) {
 114       // found target assignment program - no need to parse further
 115       return rvalue_ast;
 116     }
 117
 118     dependent_programs[lvalue_name] = rvalue_ast;
 119     cur = assign_index + 1;
 120   }
 121
 122   return nullptr;
 123 }
 124
 125 bool lldb_private::npdb::TranslateFPOProgramToDWARFExpression(
 126     llvm::StringRef program, llvm::StringRef register_name,
 127     llvm::Triple::ArchType arch_type, Stream &stream) {
 128   llvm::BumpPtrAllocator node_alloc;
 129   Node *target_program =
 130       ParseFPOProgram(program, register_name, arch_type, node_alloc);
 131   if (target_program == nullptr) {
 132     return false;
 133   }
 134
 135   ToDWARF(*target_program, stream);
 136   return true;
 137 }