ed/raddebugger
1
0 Fork 0
mirror of https://github.com/Ed94/raddebugger.git synced 2026-10-14 12:59:41 -07:00
Code Issues Packages Projects Releases Wiki Activity

factor out weak symbol resolution logic and apply it to the symbol table

Browse Source 
when building link context
This commit is contained in:
Nikita Smith authored and Ryan Fleury committed 2025-07-23 16:09:48 -07:00
1 parent 7cd5a670e3
commit d32667546d
9 files changed
+516 -727
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

src/linker/lnk_symbol_table.c
+164 -75
View File
@@ -39,6 +39,20 @@ lnk_make_undefined_symbol(Arena *arena, String8 name, struct LNK_Obj *obj)
return symbol;
}
internal B32
lnk_symbol_defined_is_before(void *raw_a, void *raw_b)
{
LNK_Symbol *a = raw_a, *b = raw_b;
return a->u.defined.obj->input_idx < b->u.defined.obj->input_idx;
}
internal B32
lnk_symbol_lib_is_before(void *raw_a, void *raw_b)
{
LNK_Symbol *a = raw_a, *b = raw_b;
return a->u.lib.lib->input_idx < b->u.lib.lib->input_idx;
}
internal void
lnk_symbol_list_push_node(LNK_SymbolList *list, LNK_SymbolNode *node)
{
@@ -123,41 +137,27 @@ lnk_error_multiply_defined_symbol(LNK_Symbol *dst, LNK_Symbol *src)
internal B32
lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
{
//Assert(src->type != LNK_Symbol_Undefined);
Assert(dst != src);
Assert(str8_match(dst->name, src->name, 0));
B32 can_replace = 0;
switch (scope) {
case LNK_SymbolScope_Lib: {
// link.exe picks symbol from lib that is discovered first
can_replace = src->u.lib.lib->input_idx < dst->u.lib.lib->input_idx;
} break;
case LNK_SymbolScope_Import: {
can_replace = 1;
} break;
case LNK_SymbolScope_Defined: {
LNK_Obj *dst_obj = dst->u.defined.obj;
LNK_Obj *src_obj = src->u.defined.obj;
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_SymbolValueInterpType dst_interp = coff_interp_symbol(dst_parsed.section_number, dst_parsed.value, dst_parsed.storage_class);
COFF_SymbolValueInterpType src_interp = coff_interp_symbol(src_parsed.section_number, src_parsed.value, src_parsed.storage_class);
LNK_Obj *dst_obj = dst->u.defined.obj;
LNK_Obj *src_obj = src->u.defined.obj;
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_SymbolValueInterpType dst_interp = coff_interp_from_parsed_symbol(dst_parsed);
COFF_SymbolValueInterpType src_interp = coff_interp_from_parsed_symbol(src_parsed);
// regular vs abs
if (dst_interp == COFF_SymbolValueInterp_Regular && src_interp == COFF_SymbolValueInterp_Abs) {
lnk_error_multiply_defined_symbol(dst, src);
}
// abs vs regular
else if ((dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Regular) ||
(dst_interp == COFF_SymbolValueInterp_Regular && src_interp == COFF_SymbolValueInterp_Abs)) {
else if (dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Regular) {
lnk_error_multiply_defined_symbol(dst, src);
}
// abs vs common
else if (dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Common) {
if (dst->u.defined.obj->input_idx < src->u.defined.obj->input_idx) {
if (lnk_symbol_defined_is_before(dst, src)) {
can_replace = 1;
} else {
lnk_error_multiply_defined_symbol(dst, src);
@@ -165,43 +165,35 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
}
// common vs abs
else if (dst_interp == COFF_SymbolValueInterp_Common && src_interp == COFF_SymbolValueInterp_Abs) {
if (dst->u.defined.obj->input_idx < src->u.defined.obj->input_idx) {
if (lnk_symbol_defined_is_before(dst, src)) {
lnk_error_multiply_defined_symbol(dst, src);
}
}
// abs vs abs
else if (dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Abs) {
lnk_error_multiply_defined_symbol(dst, src);
}
// weak vs weak
else if (dst_interp == COFF_SymbolValueInterp_Weak && src_interp == COFF_SymbolValueInterp_Weak) {
can_replace = src->u.defined.obj->input_idx < dst->u.defined.obj->input_idx;
can_replace = lnk_symbol_defined_is_before(src, dst);
}
// weak vs abs
else if (dst_interp == COFF_SymbolValueInterp_Weak && src_interp == COFF_SymbolValueInterp_Abs) {
// weak vs regular/abs/common
else if (dst_interp == COFF_SymbolValueInterp_Weak && (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Abs || src_interp == COFF_SymbolValueInterp_Common)) {
can_replace = 1;
}
// abs vs weak
else if (dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Weak) {
// regular/abs/common vs weak
else if ((dst_interp == COFF_SymbolValueInterp_Regular || dst_interp == COFF_SymbolValueInterp_Abs || dst_interp == COFF_SymbolValueInterp_Common) && src_interp == COFF_SymbolValueInterp_Weak) {
can_replace = 0;
}
// weak vs (regular, common, abs)
else if (dst_interp == COFF_SymbolValueInterp_Weak && (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common || src_interp == COFF_SymbolValueInterp_Abs)) {
can_replace = 1;
}
// regular vs weak
else if (dst_interp == COFF_SymbolValueInterp_Regular && src_interp == COFF_SymbolValueInterp_Weak) {
can_replace = 0;
}
// (regular, common) vs (regular, common)
// regular/common vs regular/common
else if ((dst_interp == COFF_SymbolValueInterp_Regular || dst_interp == COFF_SymbolValueInterp_Common) && (src_interp == COFF_SymbolValueInterp_Regular || src_interp == COFF_SymbolValueInterp_Common)) {
// parse dst symbol properties
B32 dst_is_comdat = 0;
COFF_ComdatSelectType dst_select;
U32 dst_section_length;
U32 dst_check_sum;
if (dst_interp == COFF_SymbolValueInterp_Regular) {
U32 dst_comdat_symbol_idx = dst_obj->comdats[dst_parsed.section_number-1];
if (dst_comdat_symbol_idx != max_U32) {
COFF_ParsedSymbol secdef = lnk_parsed_symbol_from_coff_symbol_idx(dst_obj, dst_comdat_symbol_idx);
coff_parse_secdef(secdef, dst_obj->header.is_big_obj, &dst_select, 0, &dst_section_length, &dst_check_sum);
dst_is_comdat = 1;
}
dst_is_comdat = lnk_try_comdat_props_from_section_number(dst->u.defined.obj, dst_parsed.section_number, &dst_select, &dst_section_length, &dst_check_sum);
} else if (dst_interp == COFF_SymbolValueInterp_Common) {
dst_select = COFF_ComdatSelect_Largest;
dst_section_length = dst_parsed.value;
@@ -209,17 +201,13 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
dst_is_comdat = 1;
}
// parse src symbol properties
B32 src_is_comdat = 0;
COFF_ComdatSelectType src_select;
U32 src_section_length;
U32 src_section_length, src_checks;
U32 src_check_sum;
if (src_interp == COFF_SymbolValueInterp_Regular) {
U32 src_comdat_symbol_idx = src_obj->comdats[src_parsed.section_number-1];
if (src_comdat_symbol_idx != max_U32) {
COFF_ParsedSymbol secdef = lnk_parsed_symbol_from_coff_symbol_idx(src_obj, src_comdat_symbol_idx);
coff_parse_secdef(secdef, src_obj->header.is_big_obj, &src_select, 0, &src_section_length, &src_check_sum);
src_is_comdat = 1;
}
src_is_comdat = lnk_try_comdat_props_from_section_number(src->u.defined.obj, src_parsed.section_number, &src_select, &src_section_length, &src_check_sum);
} else if (src_interp == COFF_SymbolValueInterp_Common) {
src_select = COFF_ComdatSelect_Largest;
src_section_length = src_parsed.value;
@@ -228,18 +216,15 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
}
// regular non-comdat vs communal
if (dst_interp == COFF_SymbolValueInterp_Regular && !dst_is_comdat &&
src_interp == COFF_SymbolValueInterp_Common) {
if (dst_interp == COFF_SymbolValueInterp_Regular && !dst_is_comdat && src_interp == COFF_SymbolValueInterp_Common) {
can_replace = 0;
}
// communal vs regular non-comdat
else if (dst_interp == COFF_SymbolValueInterp_Common &&
src_interp == COFF_SymbolValueInterp_Regular && !src_is_comdat) {
else if (dst_interp == COFF_SymbolValueInterp_Common && src_interp == COFF_SymbolValueInterp_Regular && !src_is_comdat) {
can_replace = 1;
}
// handle COMDATs
else if (dst_is_comdat && src_is_comdat) {
// handle objs compiled with /GR- and /GR
if ((src_select == COFF_ComdatSelect_Any && dst_select == COFF_ComdatSelect_Largest)) {
src_select = COFF_ComdatSelect_Largest;
}
@@ -252,7 +237,7 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
case COFF_ComdatSelect_Null:
case COFF_ComdatSelect_Any: {
if (src_section_length == dst_section_length) {
can_replace = src_obj->input_idx < dst_obj->input_idx;
can_replace = lnk_obj_is_before(src_obj, dst_obj);
} else {
// both COMDATs are valid but to get smaller exe pick smallest
can_replace = src_section_length < dst_section_length;
@@ -263,19 +248,17 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
} break;
case COFF_ComdatSelect_SameSize: {
if (dst_section_length == src_section_length) {
can_replace = src_obj->input_idx < dst_obj->input_idx;
can_replace = lnk_obj_is_before(src_obj, dst_obj);
} else {
lnk_error_multiply_defined_symbol(dst, src);
}
} break;
case COFF_ComdatSelect_ExactMatch: {
COFF_SectionHeader *dst_section_table = (COFF_SectionHeader *)str8_substr(dst_obj->data, dst_obj->header.section_table_range).str;
COFF_SectionHeader *src_section_table = (COFF_SectionHeader *)str8_substr(src_obj->data, src_obj->header.section_table_range).str;
COFF_SectionHeader *dst_sect_header = &dst_section_table[dst_parsed.section_number-1];
COFF_SectionHeader *src_sect_header = &src_section_table[src_parsed.section_number-1];
String8 dst_data = str8_substr(dst_obj->data, rng_1u64(dst_sect_header->foff, dst_sect_header->foff + dst_sect_header->fsize));
String8 src_data = str8_substr(src_obj->data, rng_1u64(src_sect_header->foff, src_sect_header->foff + src_sect_header->fsize));
B32 is_exact_match = 0;
COFF_SectionHeader *dst_sect_header = lnk_coff_section_header_from_section_number(dst_obj, dst_parsed.section_number);
COFF_SectionHeader *src_sect_header = lnk_coff_section_header_from_section_number(src_obj, src_parsed.section_number);
String8 dst_data = str8_substr(dst_obj->data, rng_1u64(dst_sect_header->foff, dst_sect_header->foff + dst_sect_header->fsize));
String8 src_data = str8_substr(src_obj->data, rng_1u64(src_sect_header->foff, src_sect_header->foff + src_sect_header->fsize));
B32 is_exact_match = 0;
if (dst_check_sum != 0 && src_check_sum != 0) {
is_exact_match = dst_check_sum == src_check_sum && str8_match(dst_data, src_data, 0);
} else {
@@ -283,29 +266,25 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
}
if (is_exact_match) {
can_replace = src_obj->input_idx < dst_obj->input_idx;
can_replace = lnk_obj_is_before(src_obj, dst_obj);
} else {
lnk_error_multiply_defined_symbol(dst, src);
}
} break;
case COFF_ComdatSelect_Largest: {
if (dst_section_length == src_section_length) {
can_replace = src_obj->input_idx < dst_obj->input_idx;
can_replace = lnk_obj_is_before(src_obj, dst_obj);
} else {
can_replace = dst_section_length < src_section_length;
}
} break;
case COFF_ComdatSelect_Associative: {
// ignore
} break;
default: { InvalidPath; }
case COFF_ComdatSelect_Associative: { /* ignore */ } break;
default: { InvalidPath; } break;
}
} else {
String8 src_select_str = coff_string_from_comdat_select_type(src_select);
String8 dst_select_str = coff_string_from_comdat_select_type(dst_select);
lnk_error_obj(LNK_Warning_UnresolvedComdat, src_obj,
"%S: COMDAT selection conflict detected, current selection %S, leader selection %S from %S",
src->name, src_select_str, dst_select_str, dst_obj);
src->name, coff_string_from_comdat_select_type(src_select), coff_string_from_comdat_select_type(dst_select), dst_obj);
}
} else {
lnk_error_multiply_defined_symbol(dst, src);
@@ -314,9 +293,15 @@ lnk_can_replace_symbol(LNK_SymbolScope scope, LNK_Symbol *dst, LNK_Symbol *src)
lnk_error(LNK_Error_InvalidPath, "unable to find a suitable replacement logic for symbol combination");
}
} break;
case LNK_SymbolScope_Import: {
lnk_error_multiply_defined_symbol(dst, src);
} break;
case LNK_SymbolScope_Lib: {
// link.exe picks symbol from lib that is discovered first
can_replace = lnk_symbol_lib_is_before(src, dst);
} break;
default: { InvalidPath; }
}
return can_replace;
}
@@ -521,6 +506,110 @@ lnk_symbol_table_push_alt_name(LNK_SymbolTable *symtab, LNK_Obj *obj, String8 fr
}
}
internal
THREAD_POOL_TASK_FUNC(lnk_finalize_weak_symbols_task)
{
Temp scratch = scratch_begin(&arena,1);
LNK_FinalizeWeakSymbolsTask *task = raw_task;
LNK_SymbolTable *symtab = task->symtab;
LNK_SymbolHashTrieChunk *chunk = task->chunks[task_id];
for EachIndex(i, chunk->count) {
LNK_Symbol *symbol = chunk->v[i].symbol;
COFF_ParsedSymbol symbol_parsed = lnk_parsed_symbol_from_coff_symbol_idx(symbol->u.defined.obj, symbol->u.defined.symbol_idx);
COFF_SymbolValueInterpType symbol_interp = coff_interp_symbol(symbol_parsed.section_number, symbol_parsed.value, symbol_parsed.storage_class);
if (symbol_interp == COFF_SymbolValueInterp_Weak) {
struct LookupLocation { struct LookupLocation *next; LNK_SymbolDefined symbol; };
struct LookupLocation *lookup_first = 0, *lookup_last = 0;
LNK_SymbolDefined current_symbol = symbol->u.defined;
for (;;) {
// guard against self-referencing weak symbols
struct LookupLocation *was_visited = 0;
for (struct LookupLocation *l = lookup_first; l != 0; l = l->next) {
if (MemoryCompare(&l->symbol, &current_symbol, sizeof(LNK_SymbolDefined)) == 0) { was_visited = l; break; }
}
if (was_visited) {
Temp temp = temp_begin(scratch.arena);
String8List ref_list = {0};
for (struct LookupLocation *l = lookup_first; l != 0; l = l->next) {
COFF_ParsedSymbol loc_symbol = lnk_parsed_symbol_from_coff_symbol_idx(l->symbol.obj, l->symbol.symbol_idx);
str8_list_pushf(temp.arena, &ref_list, "\t%S Symbol %S (No. %#x) =>", l->symbol.obj->path, loc_symbol.name, l->symbol.symbol_idx);
}
COFF_ParsedSymbol loc_symbol = lnk_parsed_symbol_from_coff_symbol_idx(lookup_first->symbol.obj, lookup_first->symbol.symbol_idx);
str8_list_pushf(temp.arena, &ref_list, "\t%S Symbol %S (No. %#x)", lookup_first->symbol.obj->path, loc_symbol.name, lookup_first->symbol.symbol_idx);
COFF_ParsedSymbol parsed_symbol = lnk_parsed_symbol_from_coff_symbol_idx(symbol->u.defined.obj, symbol->u.defined.symbol_idx);
String8 loc_string = str8_list_join(temp.arena, &ref_list, &(StringJoin){ .sep = str8_lit("\n") });
lnk_error_obj(LNK_Error_WeakCycle, symbol->u.defined.obj, "unable to resolve cyclic symbol %S; ref chain:\n%S", parsed_symbol.name, loc_string);
MemoryZeroStruct(&current_symbol);
temp_end(temp);
break;
}
// record visited symbol
struct LookupLocation *loc = push_array(scratch.arena, struct LookupLocation, 1);
loc->symbol = current_symbol;
SLLQueuePush(lookup_first, lookup_last, loc);
COFF_ParsedSymbol current_parsed = lnk_parsed_symbol_from_coff_symbol_idx(current_symbol.obj, current_symbol.symbol_idx);
COFF_SymbolValueInterpType current_interp = coff_interp_symbol(current_parsed.section_number, current_parsed.value, current_parsed.storage_class);
if (current_interp != COFF_SymbolValueInterp_Weak && current_interp != COFF_SymbolValueInterp_Undefined) {
break;
}
// does weak symbol have the strong definition?
LNK_Symbol *defn_symbol = lnk_symbol_table_search(symtab, LNK_SymbolScope_Defined, current_parsed.name);
COFF_ParsedSymbol defn_parsed = lnk_parsed_symbol_from_coff_symbol_idx(defn_symbol->u.defined.obj, defn_symbol->u.defined.symbol_idx);
COFF_SymbolValueInterpType defn_interp = coff_interp_symbol(defn_parsed.section_number, defn_parsed.value, defn_parsed.storage_class);
if (defn_interp != COFF_SymbolValueInterp_Weak) {
current_symbol = defn_symbol->u.defined;
break;
}
// no strong definition fallback to the tag
COFF_SymbolWeakExt *weak_ext = coff_parse_weak_tag(current_parsed, current_symbol.obj->header.is_big_obj);
COFF_ParsedSymbol tag_parsed = lnk_parsed_symbol_from_coff_symbol_idx(current_symbol.obj, weak_ext->tag_index);
COFF_SymbolValueInterpType tag_interp = coff_interp_symbol(tag_parsed.section_number, tag_parsed.value, tag_parsed.storage_class);
current_symbol = (LNK_SymbolDefined){ .obj = current_symbol.obj, .symbol_idx = weak_ext->tag_index };
}
// replace weak symbol with it's tag
symbol->u.defined = current_symbol;
}
}
scratch_end(scratch);
}
internal void
lnk_finalize_weak_symbols(TP_Context *tp, LNK_SymbolTable *symtab)
{
ProfBeginFunction();
Temp scratch = scratch_begin(0,0);
U64 chunks_count = 0;
for EachIndex(worker_id, tp->worker_count) { chunks_count += symtab->chunk_lists[LNK_SymbolScope_Defined][worker_id].count; }
LNK_SymbolHashTrieChunk **chunks = push_array(scratch.arena, LNK_SymbolHashTrieChunk *, chunks_count);
U64 chunks_cursor = 0;
for EachIndex(worker_id, tp->worker_count) {
for (LNK_SymbolHashTrieChunk *chunk = symtab->chunk_lists[LNK_SymbolScope_Defined][worker_id].first; chunk != 0; chunk = chunk->next) {
chunks[chunks_cursor++] = chunk;
}
}
LNK_FinalizeWeakSymbolsTask task = { .symtab = symtab, .chunks = chunks };
tp_for_parallel(tp, 0, chunks_count, lnk_finalize_weak_symbols_task, &task);
scratch_end(scratch);
ProfEnd();
}
internal COFF_ParsedSymbol
lnk_parsed_symbol_from_defined(LNK_Symbol *symbol)
{