handle COMDAT Associative selection

src/linker/lnk.c

@@ -2201,6 +2201,44 @@ lnk_build_win32_image(TP_Arena *arena, TP_Context *tp, LNK_Config *config, LNK_S
   U64       objs_count = obj_list.count;
   LNK_Obj **objs       = lnk_obj_arr_from_list(scratch.arena, obj_list);
 
+  ProfBegin("Remove Associatives");
+  {
+    for (U64 obj_idx = 0; obj_idx < objs_count; obj_idx += 1) {
+      LNK_Obj *obj = objs[obj_idx];
+      String8 string_table = str8_substr(obj->data, obj->header.string_table_range);
+      String8 symbol_table = str8_substr(obj->data, obj->header.symbol_table_range);
+      for (U64 sect_idx = 0; sect_idx < obj->header.section_count_no_null; sect_idx += 1) {
+        // find associate section head section index
+        U32 head_sect_idx = max_U32;
+        for (U64 current_sect_idx = sect_idx;;) {
+          U32 symbol_idx = obj->comdats[current_sect_idx];
+          if (symbol_idx == max_U32) {
+            break;
+          }
+
+          COFF_ParsedSymbol symbol = coff_parse_symbol(obj->header, string_table, symbol_table, symbol_idx);
+          COFF_ComdatSelectType selection = COFF_ComdatSelect_Null;
+          U32 section_number = 0;
+          coff_parse_secdef(symbol, obj->header.is_big_obj, &selection, &section_number, 0, 0);
+          if (selection != COFF_ComdatSelect_Associative) {
+            head_sect_idx = current_sect_idx;
+            break;
+          }
+
+          current_sect_idx = section_number-1;
+        }
+
+        if (head_sect_idx != max_U32) {
+          // flag current section with remove if head section was removed
+          COFF_SectionHeader *head_sect_header = lnk_coff_section_header_from_section_number(obj, head_sect_idx+1);
+          COFF_SectionHeader *curr_sect_header = lnk_coff_section_header_from_section_number(obj, sect_idx+1);
+          curr_sect_header->flags |= (head_sect_header->flags & COFF_SectionFlag_LnkRemove);
+        }
+      }
+    }
+  }
+  ProfEnd();
+
   {
     ProfBegin("Define And Count Sections");
     Temp temp = temp_begin(scratch.arena);

src/linker/lnk_error.h

@@ -38,6 +38,7 @@ typedef enum
   LNK_Error_IllegalRelocation,
   LNK_Error_CircularMerge,
   LNK_Error_UnresolvedSymbol,
+  LNK_Error_AssociativeLoop,
   LNK_Error_StopLast,
   
   LNK_Error_First,

src/linker/lnk_obj.c

@@ -116,6 +116,35 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
     }
   }
 
+  //
+  // error check symbols
+  //
+  {
+    COFF_SectionHeader *section_table = (COFF_SectionHeader *)str8_substr(input->data, header.section_table_range).str;
+    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)) {
+      symbol = coff_parse_symbol(header, string_table, symbol_table, symbol_idx);
+      COFF_SymbolValueInterpType interp = coff_interp_symbol(symbol.section_number, symbol.value, symbol.storage_class);
+      if (interp == COFF_SymbolValueInterp_Regular) {
+        if (symbol.section_number == 0 || symbol.section_number > header.section_count_no_null) {
+          lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "symbol %S (No. 0x%x) points to an out of bounds section 0x%x", symbol.name, symbol_idx, symbol.section_number);
+        }
+        if (symbol.storage_class == COFF_SymStorageClass_Static && symbol.aux_symbol_count > 0) {
+          COFF_ComdatSelectType select;
+          U32 section_number = 0;
+          coff_parse_secdef(symbol, header.is_big_obj, &select, &section_number, 0, 0);
+          if (select == COFF_ComdatSelect_Associative) {
+            if (section_number == 0 || section_number > header.section_count_no_null) {
+              lnk_error_with_loc(LNK_Error_IllData, input->path, input->lib_path, "section definition symbol %S (No. 0x%x) associates with an out of bounds section 0x%x", symbol.name, symbol_idx, symbol.section_number);
+            }
+          }
+        }
+      }
+    }
+  }
+
   //
   // create symbol links to COMDAT sections
   //
@@ -128,11 +157,7 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
     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_symbol(header, string_table, symbol_table, symbol_idx);
-        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) {
@@ -162,6 +187,57 @@ THREAD_POOL_TASK_FUNC(lnk_obj_initer)
     }
   }
 
+  //
+  // COMDAT loop checker
+  //
+  {
+    Temp scratch = scratch_begin(&arena, 1);
+
+    String8    string_table     = str8_substr(input->data, header.string_table_range);
+    String8    symbol_table     = str8_substr(input->data, header.symbol_table_range);
+    HashTable *visited_sections = hash_table_init(scratch.arena, 32);
+    for (U64 sect_idx = 0; sect_idx < header.section_count_no_null; sect_idx += 1) {
+      for (U32 curr_section = sect_idx;;) {
+        U32 symbol_idx = comdats[curr_section];
+
+        // is section COMDAT?
+        if (symbol_idx == max_U32) {
+          break;
+        }
+
+        // extract COMDAT info for current section
+        COFF_ParsedSymbol     symbol         = coff_parse_symbol(header, string_table, symbol_table, symbol_idx);
+        COFF_ComdatSelectType select         = COFF_ComdatSelect_Null;
+        U32                   section_number = 0;
+        coff_parse_secdef(symbol, header.is_big_obj, &select, &section_number, 0, 0);
+
+        if (select != COFF_ComdatSelect_Associative) {
+          // section terminates at non-associative COMDAT -- no loop
+          break;
+        }
+
+        // was section visited? -- loop found
+        if (hash_table_search_u64(visited_sections, curr_section)) {
+          COFF_ParsedSymbol symbol = coff_parse_symbol(header, string_table, symbol_table, comdats[sect_idx]);
+          lnk_error_with_loc(LNK_Error_AssociativeLoop, input->path, input->lib_path, "section symbol %S (No. 0x%x) does not terminate on a non-associate COMDAT symbol", symbol.name, comdats[sect_idx]);
+          break;
+        }
+
+        // track visited sections
+        hash_table_push_u64_u64(scratch.arena, visited_sections, curr_section, 0);
+
+        // follow association
+        Assert(section_number > 0);
+        curr_section = section_number-1;
+      }
+
+      // purge hash table for next run
+      hash_table_purge(visited_sections);
+    }
+
+    scratch_end(scratch);
+  }
+
   // fill out obj
   obj->data      = input->data;
   obj->path      = push_str8_copy(arena, input->path);

src/linker/lnk_symbol_table.c

@@ -229,13 +229,11 @@ lnk_can_replace_symbol(LNK_Symbol *dst, LNK_Symbol *src)
       can_replace = 0;
     }
     // weak vs regular,common,abs
-    else if (dst_interp == COFF_SymbolValueInterp_Weak &&
+    else if (dst_interp == COFF_SymbolValueInterp_Weak && (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common || src_interp == COFF_SymbolValueInterp_Abs)) {
-        (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common || src_interp == COFF_SymbolValueInterp_Abs)) {
       can_replace = 1;
     }
     // regular,common vs regular,common
-    else if ((dst_interp == COFF_SymbolValueInterp_Regular || dst_interp == COFF_SymbolValueInterp_Common) &&
+    else if ((dst_interp == COFF_SymbolValueInterp_Regular || dst_interp == COFF_SymbolValueInterp_Common) && (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common)) {
-             (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common)) {
       U32 dst_comdat_symbol_idx = dst_obj->comdats[dst_parsed.section_number-1];
       U32 src_comdat_symbol_idx = src_obj->comdats[src_parsed.section_number-1];
       if (dst_comdat_symbol_idx == ~0 || src_comdat_symbol_idx == ~0) {