Update relocations

1 files changed, 74 insertions, 3 deletions

diff --git a/bxgen.c b/bxgen.c
index 33a6908..9d6781c 100755
--- a/bxgen.c
+++ b/bxgen.c
@@ -779,6 +779,12 @@ void unit_write(Pool *pool, i64 unit, u16 target, i64 io_out, void *io_user_data
   //  AR         https://man.freebsd.org/cgi/man.cgi?query=ar&sektion=5
   //  ELF        https://man7.org/linux/man-pages/man5/elf.5.html
   //
+  //  Relocation types
+  //  https://intezer.com/blog/malware-analysis/executable-and-linkable-format-101-part-3-relocations/
+  //  https://docs.oracle.com/cd/E19120-01/open.solaris/819-0690/chapter7-2/index.html
+  //
+  //  https://web.archive.org/web/20150324024617/http://mylinuxbook.com/readelf-command/
+  //
   //  LLVM impl  https://github.com/llvm/llvm-project/blob/main/lld/ELF/Driver.cpp#L2822
   //             https://github.com/llvm/llvm-project/blob/main/lld/ELF/Writer.cpp#L304
   //             https://github.com/llvm/llvm-project/blob/main/lld/ELF/OutputSections.cpp#L469
@@ -1315,10 +1321,9 @@ void unit_write(Pool *pool, i64 unit, u16 target, i64 io_out, void *io_user_data
             switch (type) {
               //  ================================================================
               //
-              //  Symbols and dynamic linking symbols
+              //  Symbols
 
-              case 2:
-              case 6: {
+              case 2: {
                 //  Find symbol addresses
                 //
 
@@ -1404,6 +1409,8 @@ void unit_write(Pool *pool, i64 unit, u16 target, i64 io_out, void *io_user_data
                     }[sym_info & 0xf] : ""
                   );
 
+                  printf("%-3d", sym_shndx);
+
                   if (sym_size != 0)
                     printf("- %lld bytes", sym_size);
                   printf("\n");
@@ -1456,6 +1463,16 @@ void unit_write(Pool *pool, i64 unit, u16 target, i64 io_out, void *io_user_data
               //  ================================================================
               //
               //  Relocarions with addends
+              //
+              //    for .rela.NAME:
+              //
+              //    .NAME[rela_offset] <- calc_reloc(
+              //      B = base_memory_address
+              //      P = rela_offset
+              //      A = rela_addent
+              //      S = .symtab[rela_sym].sym_value
+              //      Z = .symtab[rela_sym].sym_size
+              //    )
 
               case 4: {
                   BX_ASSERT(entsize == 24);
@@ -1482,6 +1499,60 @@ void unit_write(Pool *pool, i64 unit, u16 target, i64 io_out, void *io_user_data
                     printf("    ");
 
                     printf("%08llx  sym %-2d  type %-2d  add %-2lld", rela_offset, rela_sym, rela_type, rela_addent);
+
+                    //  Check value from destination address
+                    //
+                    {
+                      i64 prev_offset     = current_offset;
+                      i64 prev_byte_count = byte_count;
+
+                      u64 sym_size = 0;
+
+                      //  Go to the symbol table
+                      for (u64 j = 0; j < section_count; ++j) {
+                        io_seek(f, begin_offset + section_header_offset + j * 64 + 4, IO_SEEK_BEGIN, io_user_data);
+                        u32 type;
+                        READ(type);
+
+                        if (type != 2) continue;
+
+                        io_seek(f, 16, IO_SEEK_CURSOR, io_user_data);
+                        u64 offset;
+                        READ(offset);
+
+                        io_seek(f, begin_offset + offset + rela_sym * 24 + 16, IO_SEEK_BEGIN, io_user_data);
+                        READ(sym_size);
+
+                        break;
+                      }
+
+                      if (sym_size > 0) {
+                        //  NOTE Ad hok
+                        //  Go to the previous section
+                        io_seek(f, begin_offset + section_header_offset + (i - 1) * 64 + 24, IO_SEEK_BEGIN, io_user_data);
+
+                        u64 offset;
+                        u64 size;
+                        READ(offset);
+                        READ(size);
+
+                        if (size > 0) {
+                          io_seek(f, begin_offset + offset + rela_offset, IO_SEEK_BEGIN, io_user_data);
+                          static u8 buf[4];
+                          if (sym_size > 4)
+                            sym_size = 4;
+                          io_read(f, sym_size, buf, io_user_data);
+
+                          for (u32 k = 0; k < sym_size; ++k)
+                            BX_ASSERT(buf[k] == 0);
+                        }
+                      }
+
+                      io_seek(f, prev_offset, IO_SEEK_BEGIN, io_user_data);
+                      current_offset = prev_offset;
+                      byte_count     = prev_byte_count;
+                    }
+
                     printf("\n");
                   }