store symbol links for COMDAT

src/linker/lnk.c

@@ -2369,37 +2369,18 @@ lnk_build_win32_image(TP_Arena *arena, TP_Context *tp, LNK_Config *config, LNK_S
 
     // build obj section map
     for (U64 obj_idx = 0; obj_idx < objs_count; obj_idx += 1) {
-      LNK_Obj            *obj           = objs[obj_idx];
+      LNK_Obj *obj = objs[obj_idx];
-      COFF_SectionHeader *section_table = (COFF_SectionHeader *)str8_substr(obj->data, obj->header.section_table_range).str;
+      COFF_ParsedSymbol symbol;
-      String8             string_table  = str8_substr(obj->data, obj->header.string_table_range);
+      for (U64 symbol_idx = 0; symbol_idx < obj->header.symbol_count; symbol_idx += (1 + symbol.aux_symbol_count)) {
-
+        symbol = lnk_parsed_symbol_from_coff_symbol_idx(obj, symbol_idx);
-      String8 *symlinks = push_array(scratch.arena, String8, obj->header.section_count_no_null);
+        COFF_SymbolValueInterpType interp = coff_interp_symbol(symbol.section_number, symbol.value, symbol.storage_class);
-      {
+        if (interp == COFF_SymbolValueInterp_Regular && symbol.storage_class == COFF_SymStorageClass_External && symbol.value == 0) {
-        COFF_ParsedSymbol symbol;
+          COFF_SectionHeader *sect_header = lnk_coff_section_header_from_section_number(obj, symbol.section_number);
-        for (U64 symbol_idx = 0; symbol_idx < obj->header.symbol_count; symbol_idx += (1 + symbol.aux_symbol_count)) {
+          if (sect_header->flags & COFF_SectionFlag_LnkCOMDAT) {
-          symbol = lnk_parsed_symbol_from_coff_symbol_idx(obj, symbol_idx);
+            // replace contrib with leader
-          COFF_SymbolValueInterpType interp = coff_interp_symbol(symbol.section_number, symbol.value, symbol.storage_class);
+            LNK_Symbol *defn = lnk_symbol_table_search(symtab, LNK_SymbolScope_Defined, symbol.name);
-          if (interp == COFF_SymbolValueInterp_Regular) {
+            COFF_ParsedSymbol symbol = lnk_parsed_symbol_from_coff_symbol_idx(defn->u.defined.obj, defn->u.defined.symbol_idx);
-            if (symbol.storage_class == COFF_SymStorageClass_External) {
+            sect_map[obj_idx][symbol.section_number - 1] = sect_map[defn->u.defined.obj->input_idx][symbol.section_number - 1];
-              U64 sect_idx = symbol.section_number-1;
-              COFF_SectionHeader *sect_header = &section_table[sect_idx];
-              if (sect_header->flags & COFF_SectionFlag_LnkCOMDAT) {
-                // TODO: check that we don't override COMDAT symbol link
-                symlinks[sect_idx] = symbol.name;
-              }
-            }
-          }
-        }
-      }
-
-      for (U64 sect_idx = 0; sect_idx < obj->header.section_count_no_null; sect_idx += 1) {
-        COFF_SectionHeader *sect_header = &section_table[sect_idx];
-        if (sect_header->flags & COFF_SectionFlag_LnkCOMDAT) {
-          String8 comdat_name = symlinks[sect_idx];
-          if (comdat_name.size) {
-            LNK_Symbol        *defn   = lnk_symbol_table_search(symtab, LNK_SymbolScope_Defined, comdat_name);
-            COFF_ParsedSymbol  symbol = lnk_parsed_symbol_from_coff_symbol_idx(defn->u.defined.obj, defn->u.defined.symbol_idx);
-            sect_map[obj_idx][sect_idx] = sect_map[defn->u.defined.obj->input_idx][symbol.section_number-1];
           }
         }
       }

src/linker/lnk_obj.c

@@ -48,38 +48,38 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
   //
   // parse obj header
   //
-  COFF_FileHeaderInfo coff_info = coff_file_header_info_from_data(input->data);
+  COFF_FileHeaderInfo header = coff_file_header_info_from_data(input->data);
 
   //
   // set & check machine compatibility
   //
-  if (coff_info.machine != COFF_MachineType_Unknown) {
+  if (header.machine != COFF_MachineType_Unknown) {
-    COFF_MachineType current_machine = ins_atomic_u32_eval_cond_assign(&task->machine, coff_info.machine, COFF_MachineType_Unknown);
+    COFF_MachineType current_machine = ins_atomic_u32_eval_cond_assign(&task->machine, header.machine, COFF_MachineType_Unknown);
-    if (current_machine != COFF_MachineType_Unknown && current_machine != coff_info.machine) {
+    if (current_machine != COFF_MachineType_Unknown && current_machine != header.machine) {
       lnk_error_with_loc(LNK_Error_IncompatibleMachine, input->path, input->lib_path,
           "conflicting machine types expected %S but got %S",
           coff_string_from_machine_type(current_machine),
-          coff_string_from_machine_type(coff_info.machine));
+          coff_string_from_machine_type(header.machine));
     }
   }
 
   //
   // extract COFF info
   //
-  String8 raw_coff_section_table = str8_substr(input->data, coff_info.section_table_range);
+  String8 raw_coff_section_table = str8_substr(input->data, header.section_table_range);
-  String8 raw_coff_symbol_table  = str8_substr(input->data, coff_info.symbol_table_range);
+  String8 raw_coff_symbol_table  = str8_substr(input->data, header.symbol_table_range);
-  String8 raw_coff_string_table  = str8_substr(input->data, coff_info.string_table_range);
+  String8 raw_coff_string_table  = str8_substr(input->data, header.string_table_range);
 
   //
   // error check: section table / symbol table / string table
   //
-  if (raw_coff_section_table.size != dim_1u64(coff_info.section_table_range)) {
+  if (raw_coff_section_table.size != dim_1u64(header.section_table_range)) {
     lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "corrupted file, unable to read section header table");
   }
-  if (raw_coff_symbol_table.size != dim_1u64(coff_info.symbol_table_range)) {
+  if (raw_coff_symbol_table.size != dim_1u64(header.symbol_table_range)) {
     lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "corrupted file, unable to read symbol table");
   }
-  if (raw_coff_string_table.size != dim_1u64(coff_info.string_table_range)) {
+  if (raw_coff_string_table.size != dim_1u64(header.string_table_range)) {
     lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "corrupted file, unable to read string table");
   }
 
@@ -87,7 +87,7 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
   // error check section headers
   //
   COFF_SectionHeader *coff_section_table = (COFF_SectionHeader *)raw_coff_section_table.str;
-  for (U64 sect_idx = 0; sect_idx < coff_info.section_count_no_null; sect_idx += 1) {
+  for (U64 sect_idx = 0; sect_idx < header.section_count_no_null; sect_idx += 1) {
     COFF_SectionHeader *coff_sect_header = &coff_section_table[sect_idx];
 
     // read name
@@ -97,16 +97,16 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
       if (coff_sect_header->fsize > 0) {
         Rng1U64 sect_range = rng_1u64(coff_sect_header->foff, coff_sect_header->foff + coff_sect_header->fsize);
 
-        if (contains_1u64(coff_info.header_range, coff_sect_header->foff) ||
+        if (contains_1u64(header.header_range, coff_sect_header->foff) ||
-            (coff_sect_header->fsize > 0 && contains_1u64(coff_info.header_range, sect_range.max-1))) {
+            (coff_sect_header->fsize > 0 && contains_1u64(header.header_range, sect_range.max-1))) {
           lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "header (%S No. %#llx) defines out of bounds section data (file offsets point into file header)", sect_name, sect_idx+1);
         }
-        if (contains_1u64(coff_info.section_table_range, coff_sect_header->foff) ||
+        if (contains_1u64(header.section_table_range, coff_sect_header->foff) ||
-            (coff_sect_header->fsize > 0 && contains_1u64(coff_info.section_table_range, sect_range.max-1))) {
+            (coff_sect_header->fsize > 0 && contains_1u64(header.section_table_range, sect_range.max-1))) {
           lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "header (%S No. %#llx) defines out of bounds section data (file offsets point into section header table)", sect_name, sect_idx+1);
         }
-        if (contains_1u64(coff_info.symbol_table_range, coff_sect_header->foff) ||
+        if (contains_1u64(header.symbol_table_range, coff_sect_header->foff) ||
-            (coff_sect_header->fsize > 0 && contains_1u64(coff_info.symbol_table_range, sect_range.max-1))) {
+            (coff_sect_header->fsize > 0 && contains_1u64(header.symbol_table_range, sect_range.max-1))) {
           lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "header (%S No. %#llx) defines out of bounds section data (file offsets point into symbol table)", sect_name, sect_idx+1);
         }
         if (dim_1u64(sect_range) != coff_sect_header->fsize) {
@@ -116,12 +116,59 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
     }
   }
 
+  //
+  // create symbol links to COMDAT sections
+  //
+  U32 *comdats;
+  {
+    comdats = push_array_no_zero(arena, U32, header.section_count_no_null);
+    MemorySet(comdats, 0xff, header.section_count_no_null * sizeof(comdats[0]));
+
+    String8 string_table = str8_substr(input->data, header.string_table_range);
+    String8 symbol_table = str8_substr(input->data, header.symbol_table_range);
+    COFF_ParsedSymbol symbol;
+    for (U64 symbol_idx = 0; symbol_idx < header.symbol_count; symbol_idx += (1 + symbol.aux_symbol_count)) {
+      if (header.is_big_obj) {
+        symbol = coff_parse_symbol32(string_table, (COFF_Symbol32 *)symbol_table.str + symbol_idx);
+      } else {
+        symbol = coff_parse_symbol16(string_table, (COFF_Symbol16 *)symbol_table.str + symbol_idx);
+      }
+
+      COFF_SymbolValueInterpType interp = coff_interp_symbol(symbol.section_number, symbol.value, symbol.storage_class);
+      if (interp == COFF_SymbolValueInterp_Regular) {
+        if (symbol.storage_class == COFF_SymStorageClass_Static) {
+          if (symbol.section_number > 0 && symbol.section_number <= header.section_count_no_null) {
+            COFF_SectionHeader *sect_header = &coff_section_table[symbol.section_number-1];
+            if (sect_header->flags & COFF_SectionFlag_LnkCOMDAT) {
+              if (symbol.aux_symbol_count) {
+                U32 section_length = 0;
+                coff_parse_secdef(symbol, header.is_big_obj, 0, 0, &section_length, 0);
+                if (sect_header->fsize == section_length) {
+                  if (comdats[symbol.section_number-1] == ~0) {
+                    comdats[symbol.section_number-1] = symbol_idx;
+                  } else {
+                    lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "section definition symbo (No. 0x%llx) tries to ovewrite comdat", symbol_idx);
+                  }
+                } else {
+                  lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "section size specified by section definition symbol (No 0x%llx) doesn't match size in section header (No. 0x%x); expected 0x%x got 0x%x", symbol_idx, symbol.section_number, section_length, sect_header->fsize);
+                }
+              }
+            }
+          } else {
+            lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "section definition symbol (No. 0x%llx) has out of bounds section number 0x%x", symbol_idx, symbol.section_number);
+          }
+        }
+      }
+    }
+  }
+
   // fill out obj
   obj->data      = input->data;
   obj->path      = push_str8_copy(arena, input->path);
   obj->lib_path  = push_str8_copy(arena, input->lib_path);
   obj->input_idx = obj_idx;
-  obj->header    = coff_info;
+  obj->header    = header;
+  obj->comdats   = comdats;
 }
 
 internal LNK_ObjNodeArray

src/linker/lnk_obj.h

@@ -12,6 +12,7 @@ typedef struct LNK_Obj
   String8             lib_path;
   U64                 input_idx;
   COFF_FileHeaderInfo header;
+  U32                *comdats;
 } LNK_Obj;
 
 typedef struct LNK_ObjNode
@@ -100,6 +101,7 @@ internal U32 lnk_obj_get_vol_md(LNK_Obj *obj);
 
 internal COFF_ParsedSymbol lnk_parsed_symbol_from_coff(LNK_Obj *obj, void *coff_symbol);
 internal COFF_ParsedSymbol lnk_parsed_symbol_from_coff_symbol_idx(LNK_Obj *obj, U64 symbol_idx);
+internal COFF_SectionHeader * lnk_coff_section_header_from_section_number(LNK_Obj *obj, U64 section_number);
 
 ////////////////////////////////
 

src/linker/lnk_symbol_table.c

@@ -237,25 +237,27 @@ lnk_can_replace_symbol(LNK_Symbol *dst, LNK_Symbol *src)
     else if ((dst_interp == COFF_SymbolValueInterp_Regular || dst_interp == COFF_SymbolValueInterp_Common) &&
              (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common)) {
       COFF_ComdatSelectType dst_select;
-      U32                   dst_section_length;
+      U32 dst_section_length;
-      U32                   dst_check_sum;
+      U32 dst_check_sum;
       if (dst_interp == COFF_SymbolValueInterp_Regular) {
-        coff_parse_secdef(dst_parsed, dst_obj->header.is_big_obj, &dst_select, 0, &dst_section_length, &dst_check_sum);
+        COFF_ParsedSymbol secdef = lnk_parsed_symbol_from_coff_symbol_idx(dst_obj, dst_obj->comdats[dst_parsed.section_number-1]);
+        coff_parse_secdef(secdef, dst_obj->header.is_big_obj, &dst_select, 0, &dst_section_length, &dst_check_sum);
       } else {
-        dst_select         = COFF_ComdatSelect_Largest;
+        dst_select = COFF_ComdatSelect_Largest;
         dst_section_length = dst_parsed.value;
-        dst_check_sum      = 0;
+        dst_check_sum = 0;
       }
 
       COFF_ComdatSelectType src_select;
-      U32                   src_section_length;
+      U32 src_section_length;
-      U32                   src_check_sum;
+      U32 src_check_sum;
       if (src_interp == COFF_SymbolValueInterp_Regular) {
-        coff_parse_secdef(src_parsed, src_obj->header.is_big_obj, &src_select, 0, &src_section_length, &src_check_sum);
+        COFF_ParsedSymbol secdef = lnk_parsed_symbol_from_coff_symbol_idx(src_obj, src_obj->comdats[src_parsed.section_number-1]);
+        coff_parse_secdef(secdef, src_obj->header.is_big_obj, &src_select, 0, &src_section_length, &src_check_sum);
       } else {
-        src_select         = COFF_ComdatSelect_Largest;
+        src_select = COFF_ComdatSelect_Largest;
         src_section_length = src_parsed.value;
-        src_check_sum      = 0;
+        src_check_sum = 0;
       }
 
       // handle objs compiled with /GR- and /GR
@@ -332,6 +334,12 @@ lnk_on_symbol_replace(LNK_Symbol *dst, LNK_Symbol *src)
   if (dst->type == LNK_Symbol_Lib && src->type == LNK_Symbol_Lib) {
     dst->u.lib = src->u.lib;
   } else if (dst->type == LNK_Symbol_Defined && src->type == LNK_Symbol_Defined) {
+    COFF_ParsedSymbol dst_parsed = lnk_parsed_symbol_from_coff_symbol_idx(dst->u.defined.obj, dst->u.defined.symbol_idx);
+    COFF_ParsedSymbol src_parsed = lnk_parsed_symbol_from_coff_symbol_idx(src->u.defined.obj, src->u.defined.symbol_idx);
+    COFF_SectionHeader *dst_sect = lnk_coff_section_header_from_section_number(dst->u.defined.obj, dst_parsed.section_number);
+    COFF_SectionHeader *src_sect = lnk_coff_section_header_from_section_number(src->u.defined.obj, src_parsed.section_number);
+    AssertAlways(~src_sect->flags & COFF_SectionFlag_LnkRemove);
+    dst_sect->flags |= COFF_SectionFlag_LnkRemove;
     dst->u.defined = src->u.defined;
   } else {
     InvalidPath;

src/pe/pe_make_export_table.c

@@ -139,7 +139,7 @@ pe_finalize_export_list(Arena *arena, PE_ExportParseList export_list)
     }
   }
   if (ordinal_low == max_U64) {
-    ordinal_low = 0;
+    ordinal_low = 1;
   }
 
   // assign omitted ordinals
@@ -262,7 +262,7 @@ pe_make_edata_obj(Arena               *arena,
         str8_list_push(obj_writer->arena, &string_table_sect->data, export_name_cstr);
 
         // create symbol for the name string
-        String8         export_name_symbol_name = push_str8f(obj_writer->arena, "RADNAME:%S", name);
+        String8         export_name_symbol_name = push_str8f(obj_writer->arena, "%S", name);
         COFF_ObjSymbol *export_name_symbol      = coff_obj_writer_push_symbol_static(obj_writer, export_name_symbol_name, export_name_offset, string_table_sect);
 
         // create slot for export virtual offset