src/share/vm/utilities/elfFile.cpp

rev 5729 : 8019929: PPC64 (part 107): Extend ELF-decoder to support PPC64 function descriptor tables

*** 32,50 ****
--- 32,52 ----
  #include <new>
  
  #include "memory/allocation.inline.hpp"
  #include "utilities/decoder.hpp"
  #include "utilities/elfFile.hpp"
+ #include "utilities/elfFuncDescTable.hpp"
  #include "utilities/elfStringTable.hpp"
  #include "utilities/elfSymbolTable.hpp"
  
  
  ElfFile::ElfFile(const char* filepath) {
    assert(filepath, "null file path");
    memset(&m_elfHdr, 0, sizeof(m_elfHdr));
    m_string_tables = NULL;
    m_symbol_tables = NULL;
+   m_funcDesc_table = NULL;
    m_next = NULL;
    m_status = NullDecoder::no_error;
  
    int len = strlen(filepath) + 1;
    m_filepath = (const char*)os::malloc(len * sizeof(char), mtInternal);
*** 117,143 ****
      for (int index = 0; index < m_elfHdr.e_shnum; index ++) {
        if (fread((void*)&shdr, sizeof(Elf_Shdr), 1, m_file) != 1) {
          m_status = NullDecoder::file_invalid;
          return false;
        }
!       // string table
        if (shdr.sh_type == SHT_STRTAB) {
          ElfStringTable* table = new (std::nothrow) ElfStringTable(m_file, shdr, index);
          if (table == NULL) {
            m_status = NullDecoder::out_of_memory;
            return false;
          }
          add_string_table(table);
!       } else if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
          ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(m_file, shdr);
          if (table == NULL) {
            m_status = NullDecoder::out_of_memory;
            return false;
          }
          add_symbol_table(table);
        }
      }
    }
    return true;
  }
  
  bool ElfFile::decode(address addr, char* buf, int buflen, int* offset) {
--- 119,183 ----
      for (int index = 0; index < m_elfHdr.e_shnum; index ++) {
        if (fread((void*)&shdr, sizeof(Elf_Shdr), 1, m_file) != 1) {
          m_status = NullDecoder::file_invalid;
          return false;
        }
!       // string tables
        if (shdr.sh_type == SHT_STRTAB) {
          ElfStringTable* table = new (std::nothrow) ElfStringTable(m_file, shdr, index);
          if (table == NULL) {
            m_status = NullDecoder::out_of_memory;
            return false;
          }
          add_string_table(table);
!       }
!       // symbol tables
!       else if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) {
          ElfSymbolTable* table = new (std::nothrow) ElfSymbolTable(m_file, shdr);
          if (table == NULL) {
            m_status = NullDecoder::out_of_memory;
            return false;
          }
          add_symbol_table(table);
        }
      }
+ 
+ #if defined(PPC64)
+     // Now read the .opd section wich contains the PPC64 function descriptor table.
+     // The .opd section is only available on PPC64 (see for example:
+     // http://refspecs.linuxfoundation.org/LSB_3.1.1/LSB-Core-PPC64/LSB-Core-PPC64/specialsections.html)
+     // so this code should do no harm on other platforms but because of performance reasons we only
+     // execute it on PPC64 platforms.
+     // Notice that we can only find the .opd section after we have successfully read in the string
+     // tables in the previous loop, because we need to query the name of each section which is
+     // contained in one of the string tables (i.e. the one with the index m_elfHdr.e_shstrndx).
+ 
+     // Reset the file pointer
+     if (fseek(m_file, m_elfHdr.e_shoff, SEEK_SET)) {
+       m_status = NullDecoder::file_invalid;
+       return false;
+     }
+     for (int index = 0; index < m_elfHdr.e_shnum; index ++) {
+       if (fread((void*)&shdr, sizeof(Elf_Shdr), 1, m_file) != 1) {
+         m_status = NullDecoder::file_invalid;
+         return false;
+       }
+       if (m_elfHdr.e_shstrndx != SHN_UNDEF && shdr.sh_type == SHT_PROGBITS) {
+         ElfStringTable* string_table = get_string_table(m_elfHdr.e_shstrndx);
+         if (string_table == NULL) {
+           m_status = NullDecoder::file_invalid;
+           return false;
+         }
+         char buf[8]; // '8' is enough because we only want to read ".opd"
+         if (string_table->string_at(shdr.sh_name, buf, sizeof(buf)) && !strncmp(".opd", buf, 4)) {
+           m_funcDesc_table = new (std::nothrow) ElfFuncDescTable(m_file, shdr);
+           break;
+         }
+       }
+     }
+ #endif
+ 
    }
    return true;
  }
  
  bool ElfFile::decode(address addr, char* buf, int buflen, int* offset) {
*** 149,160 ****
    int string_table_index;
    int pos_in_string_table;
    int off = INT_MAX;
    bool found_symbol = false;
    while (symbol_table != NULL) {
!     if (symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off)) {
        found_symbol = true;
      }
      symbol_table = symbol_table->m_next;
    }
    if (!found_symbol) return false;
  
--- 189,201 ----
    int string_table_index;
    int pos_in_string_table;
    int off = INT_MAX;
    bool found_symbol = false;
    while (symbol_table != NULL) {
!     if (symbol_table->lookup(addr, &string_table_index, &pos_in_string_table, &off, m_funcDesc_table)) {
        found_symbol = true;
+       break;
      }
      symbol_table = symbol_table->m_next;
    }
    if (!found_symbol) return false;