contrib/llvm/tools/lldb/include/lldb/Target/ProcessStructReader.h

   1 //===---------------------ProcessStructReader.h ------------------*- C++-*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef LLDB_TARGET_PROCESSSTRUCTREADER_H
  11 #define LLDB_TARGET_PROCESSSTRUCTREADER_H
  12
  13 #include "lldb/lldb-defines.h"
  14 #include "lldb/lldb-types.h"
  15
  16 #include "lldb/Symbol/CompilerType.h"
  17 #include "lldb/Target/Process.h"
  18 #include "lldb/Utility/ConstString.h"
  19 #include "lldb/Utility/DataBufferHeap.h"
  20 #include "lldb/Utility/DataExtractor.h"
  21 #include "lldb/Utility/Status.h"
  22
  23 #include <initializer_list>
  24 #include <map>
  25 #include <string>
  26
  27 namespace lldb_private {
  28 class ProcessStructReader {
  29 protected:
  30   struct FieldImpl {
  31     CompilerType type;
  32     size_t offset;
  33     size_t size;
  34   };
  35
  36   std::map<ConstString, FieldImpl> m_fields;
  37   DataExtractor m_data;
  38   lldb::ByteOrder m_byte_order;
  39   size_t m_addr_byte_size;
  40
  41 public:
  42   ProcessStructReader(Process *process, lldb::addr_t base_addr,
  43                       CompilerType struct_type) {
  44     if (!process)
  45       return;
  46     if (base_addr == 0 || base_addr == LLDB_INVALID_ADDRESS)
  47       return;
  48     m_byte_order = process->GetByteOrder();
  49     m_addr_byte_size = process->GetAddressByteSize();
  50
  51     for (size_t idx = 0; idx < struct_type.GetNumFields(); idx++) {
  52       std::string name;
  53       uint64_t bit_offset;
  54       uint32_t bitfield_bit_size;
  55       bool is_bitfield;
  56       CompilerType field_type = struct_type.GetFieldAtIndex(
  57           idx, name, &bit_offset, &bitfield_bit_size, &is_bitfield);
  58       // no support for bitfields in here (yet)
  59       if (is_bitfield)
  60         return;
  61       auto size = field_type.GetByteSize(nullptr);
  62       // no support for things larger than a uint64_t (yet)
  63       if (!size || *size > 8)
  64         return;
  65       ConstString const_name = ConstString(name.c_str());
  66       size_t byte_index = static_cast<size_t>(bit_offset / 8);
  67       m_fields[const_name] =
  68           FieldImpl{field_type, byte_index, static_cast<size_t>(*size)};
  69     }
  70     auto total_size = struct_type.GetByteSize(nullptr);
  71     if (!total_size)
  72       return;
  73     lldb::DataBufferSP buffer_sp(new DataBufferHeap(*total_size, 0));
  74     Status error;
  75     process->ReadMemoryFromInferior(base_addr, buffer_sp->GetBytes(),
  76                                     *total_size, error);
  77     if (error.Fail())
  78       return;
  79     m_data = DataExtractor(buffer_sp, m_byte_order, m_addr_byte_size);
  80   }
  81
  82   template <typename RetType>
  83   RetType GetField(ConstString name, RetType fail_value = RetType()) {
  84     auto iter = m_fields.find(name), end = m_fields.end();
  85     if (iter == end)
  86       return fail_value;
  87     auto size = iter->second.size;
  88     if (sizeof(RetType) < size)
  89       return fail_value;
  90     lldb::offset_t offset = iter->second.offset;
  91     if (offset + size > m_data.GetByteSize())
  92       return fail_value;
  93     return (RetType)(m_data.GetMaxU64(&offset, size));
  94   }
  95
  96   size_t GetOffsetOf(ConstString name, size_t fail_value = SIZE_MAX) {
  97     auto iter = m_fields.find(name), end = m_fields.end();
  98     if (iter == end)
  99       return fail_value;
 100     return iter->second.offset;
 101   }
 102 };
 103 }
 104
 105 #endif // utility_ProcessStructReader_h_