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42cf820972d6ab5712de0c9d965e193a529262f5
raddebugger/src/linker/lnk_symbol_table.c
T
Nikita Smith 42cf820972 cache for section flags 
modifying the section flags is expensive with COW file mappings, Windows
maps are set to 64k granularity
2026-06-12 11:40:02 -07:00

804 lines
31 KiB
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// Copyright (c) Epic Games Tools
// Licensed under the MIT license (https://opensource.org/license/mit/)
internal LNK_Symbol *
lnk_make_symbol(Arena *arena, String8 name, LNK_Obj *obj, U32 symbol_idx)
{
LNK_ObjSymbolRefNode *ref = push_array(arena, LNK_ObjSymbolRefNode, 1);
ref->v.obj = obj;
ref->v.symbol_idx = symbol_idx;
LNK_Symbol *symbol = push_array(arena, LNK_Symbol, 1);
symbol->name = name;
symbol->refs = ref;
return symbol;
}
internal int
lnk_obj_symbol_ref_is_before(void *raw_a, void *raw_b)
{
LNK_ObjSymbolRef *a_ref = raw_a;
LNK_ObjSymbolRef *b_ref = raw_b;
LNK_Lib *a_lib = lnk_obj_get_lib(a_ref->obj);
LNK_Lib *b_lib = lnk_obj_get_lib(b_ref->obj);
U32 a_lib_input_idx = a_lib ? a_lib->input_idx : 0;
U32 b_lib_input_idx = b_lib ? b_lib->input_idx : 0;
if (a_lib_input_idx == b_lib_input_idx) {
if (a_ref->obj->input_idx == b_ref->obj->input_idx) {
return a_ref->symbol_idx < b_ref->symbol_idx;
}
return a_ref->obj->input_idx < b_ref->obj->input_idx;
}
return a_lib_input_idx < b_lib_input_idx;
}
internal int
lnk_obj_symbol_ref_ptr_is_before(void *raw_a, void *raw_b)
{
LNK_ObjSymbolRef **a = raw_a, **b = raw_b;
return lnk_obj_symbol_ref_is_before(*a, *b);
}
internal int
lnk_symbol_is_before(void *raw_a, void *raw_b)
{
LNK_Symbol *a = raw_a, *b = raw_b;
LNK_ObjSymbolRef a_ref = lnk_ref_from_symbol(a);
LNK_ObjSymbolRef b_ref = lnk_ref_from_symbol(b);
return lnk_obj_symbol_ref_is_before(&a_ref, &b_ref);
}
internal int
lnk_symbol_ptr_is_before(void *raw_a, void *raw_b)
{
return lnk_symbol_is_before(*(LNK_Symbol **)raw_a, *(LNK_Symbol **)raw_b);
}
internal void
lnk_symbol_list_push_node(LNK_SymbolList *list, LNK_SymbolNode *node)
{
SLLQueuePush(list->first, list->last, node);
list->count += 1;
}
internal LNK_SymbolNode *
lnk_symbol_list_push(Arena *arena, LNK_SymbolList *list, LNK_Symbol *symbol)
{
LNK_SymbolNode *node = push_array(arena, LNK_SymbolNode, 1);
node->data = symbol;
lnk_symbol_list_push_node(list, node);
return node;
}
internal LNK_SymbolHashTrie *
lnk_symbol_hash_trie_chunk_list_push(Arena *arena, LNK_SymbolHashTrieChunkList *list, U64 cap)
{
if (list->last == 0 || list->last->count >= list->last->cap) {
LNK_SymbolHashTrieChunk *chunk = push_array(arena, LNK_SymbolHashTrieChunk, 1);
chunk->cap = cap;
chunk->v = push_array_no_zero(arena, LNK_SymbolHashTrie, cap);
SLLQueuePush(list->first, list->last, chunk);
++list->count;
}
LNK_SymbolHashTrie *result = &list->last->v[list->last->count++];
return result;
}
internal void
lnk_symbol_hash_trie_chunk_list_concat_in_place(LNK_SymbolHashTrieChunkList *list, LNK_SymbolHashTrieChunkList *to_concat)
{
SLLConcatInPlace(list, to_concat);
}
internal void
lnk_error_multiply_defined_symbol(LNK_Symbol *dst, LNK_Symbol *src)
{
LNK_ObjSymbolRef dst_ref = lnk_ref_from_symbol(dst);
LNK_ObjSymbolRef src_ref = lnk_ref_from_symbol(src);
lnk_error_obj(LNK_Error_MultiplyDefinedSymbol, dst_ref.obj, "symbol \"%S\" (No. %#x) is multiply defined in %S (No. %#x)", dst->name, dst_ref.symbol_idx, src_ref.obj->path, src_ref.symbol_idx);
}
internal B32
lnk_can_replace_symbol(LNK_Symbol *dst, LNK_Symbol *src)
{
B32 can_replace = 0;
COFF_ParsedSymbol dst_parsed = lnk_parsed_from_symbol(dst);
COFF_ParsedSymbol src_parsed = lnk_parsed_from_symbol(src);
COFF_SymbolValueInterpType dst_interp = lnk_interp_from_symbol(dst);
COFF_SymbolValueInterpType src_interp = lnk_interp_from_symbol(src);
LNK_ObjSymbolRef dst_ref = lnk_ref_from_symbol(dst);
LNK_ObjSymbolRef src_ref = lnk_ref_from_symbol(src);
LNK_Obj *dst_obj = dst_ref.obj;
LNK_Obj *src_obj = src_ref.obj;
// undefined vs regular
if (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Regular) {
can_replace = 1;
}
// (weak vs undefined) or (undefined vs weak)
else if ((dst_interp == COFF_SymbolValueInterp_Weak && src_interp == COFF_SymbolValueInterp_Undefined) || (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Weak)) {
LNK_Symbol *weak, *undef;
COFF_ParsedSymbol weak_parsed;
if (dst_interp == COFF_SymbolValueInterp_Weak) {
weak = dst, undef = src;
weak_parsed = dst_parsed;
} else {
weak = src, undef = dst;
weak_parsed = src_parsed;
}
LNK_ObjSymbolRef weak_symbol_ref = lnk_ref_from_symbol(weak);
COFF_SymbolWeakExt *weak_ext = coff_parse_weak_tag(weak_parsed, weak_symbol_ref.obj->header.is_big_obj);
if (weak_ext->characteristics == COFF_WeakExt_SearchLibrary) {
// NOTE: MSVC does not let a weak symbol to replace an undefined one,
// but LLD links without errors or warnings, meaning undefined symbols
// are resolved to the weak, which can potentially change behaviour of
// the linked image
can_replace = dst_interp == COFF_SymbolValueInterp_Weak;
} else if (weak_ext->characteristics == COFF_WeakExt_NoLibrary) {
can_replace = dst_interp == COFF_SymbolValueInterp_Weak;
} else if (weak_ext->characteristics == COFF_WeakExt_SearchAlias) {
can_replace = dst_interp == COFF_SymbolValueInterp_Undefined;
} else {
can_replace = lnk_symbol_is_before(src, dst);
}
}
// undefined vs undefined
else if (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Undefined) {
can_replace = lnk_symbol_is_before(src, dst);
}
// undefined vs common
else if (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Common) {
can_replace = 1;
}
// undefined vs abs
else if (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Abs) {
can_replace = 1;
}
// undefined vs debug
else if (dst_interp == COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Debug) {
can_replace = 1;
}
// regular/common/abs/debug vs undefined
else if (dst_interp != COFF_SymbolValueInterp_Undefined && src_interp == COFF_SymbolValueInterp_Undefined) {
can_replace = 0;
}
// regular vs abs
else 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) {
lnk_error_multiply_defined_symbol(dst, src);
}
// abs vs common
else if (dst_interp == COFF_SymbolValueInterp_Abs && src_interp == COFF_SymbolValueInterp_Common) {
if (lnk_symbol_is_before(dst, src)) {
can_replace = 1;
} else {
lnk_error_multiply_defined_symbol(dst, src);
}
}
// common vs abs
else if (dst_interp == COFF_SymbolValueInterp_Common && src_interp == COFF_SymbolValueInterp_Abs) {
if (lnk_symbol_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) {
COFF_SymbolWeakExt *dst_ext = coff_parse_weak_tag(dst_parsed, dst_ref.obj->header.is_big_obj);
COFF_SymbolWeakExt *src_ext = coff_parse_weak_tag(src_parsed, src_ref.obj->header.is_big_obj);
if ((dst_ext->characteristics == COFF_WeakExt_SearchAlias && src_ext->characteristics != COFF_WeakExt_SearchAlias)) {
if (lnk_symbol_is_before(dst, src) || src_ext->characteristics == COFF_WeakExt_AntiDependency) {
can_replace = 0;
} else {
lnk_error_multiply_defined_symbol(dst, src);
}
} else if (dst_ext->characteristics != COFF_WeakExt_SearchAlias && src_ext->characteristics == COFF_WeakExt_SearchAlias) {
if (lnk_symbol_is_before(src, dst) || dst_ext->characteristics == COFF_WeakExt_AntiDependency) {
can_replace = 1;
} else {
lnk_error_multiply_defined_symbol(dst, src);
}
} else if (dst_ext->characteristics == COFF_WeakExt_SearchAlias && src_ext->characteristics == COFF_WeakExt_SearchAlias) {
lnk_error_multiply_defined_symbol(dst, src);
} else {
can_replace = lnk_symbol_is_before(src, dst);
}
}
// 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;
}
// 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;
}
// 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) {
dst_is_comdat = lnk_try_comdat_props_from_section_number(dst_ref.obj, dst_parsed.section_number, &dst_select, 0, &dst_section_length, &dst_check_sum);
} else if (dst_interp == COFF_SymbolValueInterp_Common) {
dst_select = COFF_ComdatSelect_Largest;
dst_section_length = dst_parsed.value;
dst_check_sum = 0;
dst_is_comdat = 1;
}
// parse src symbol properties
B32 src_is_comdat = 0;
COFF_ComdatSelectType src_select;
U32 src_section_length, src_checks;
U32 src_check_sum;
if (src_interp == COFF_SymbolValueInterp_Regular) {
src_is_comdat = lnk_try_comdat_props_from_section_number(src_ref.obj, src_parsed.section_number, &src_select, 0, &src_section_length, &src_check_sum);
} else if (src_interp == COFF_SymbolValueInterp_Common) {
src_select = COFF_ComdatSelect_Largest;
src_section_length = src_parsed.value;
src_check_sum = 0;
src_is_comdat = 1;
}
// regular non-comdat vs communal
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) {
can_replace = 1;
}
// handle COMDATs
else if (dst_is_comdat && src_is_comdat) {
if ((src_select == COFF_ComdatSelect_Any && dst_select == COFF_ComdatSelect_Largest)) {
src_select = COFF_ComdatSelect_Largest;
}
if (src_select == COFF_ComdatSelect_Largest && dst_select == COFF_ComdatSelect_Any) {
dst_select = COFF_ComdatSelect_Largest;
}
if (src_select == dst_select) {
switch (src_select) {
case COFF_ComdatSelect_Null:
case COFF_ComdatSelect_Any: {
can_replace = lnk_obj_is_before(src_obj, dst_obj);
} break;
case COFF_ComdatSelect_NoDuplicates: {
lnk_error_multiply_defined_symbol(dst, src);
} break;
case COFF_ComdatSelect_SameSize: {
if (dst_section_length == src_section_length) {
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_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 {
is_exact_match = str8_match(dst_data, src_data, 0);
}
if (is_exact_match) {
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 = 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; } break;
}
} else {
lnk_error_obj(LNK_Warning_UnresolvedComdat, src_obj,
"%S: COMDAT selection conflict detected, current selection %S, leader selection %S from %S",
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);
}
} else {
lnk_error(LNK_Error_InvalidPath, "unable to find a suitable replacement logic for symbol combination");
}
return can_replace;
}
internal void
lnk_on_symbol_replace(LNK_Symbol *dst, LNK_Symbol *src)
{
COFF_ParsedSymbol dst_parsed = lnk_parsed_from_symbol(dst);
COFF_SymbolValueInterpType dst_interp = lnk_interp_from_symbol(dst);
LNK_ObjSymbolRef dst_ref = lnk_ref_from_symbol(dst);
if (dst_interp == COFF_SymbolValueInterp_Regular) {
// remove replaced section from the output
dst_ref.obj->section_flags[dst_parsed.section_number-1] |= COFF_SectionFlag_LnkRemove;
// remove associated sections from the output
for (U32Node *associated_section = dst_ref.obj->associated_sections[dst_parsed.section_number];
associated_section != 0;
associated_section = associated_section->next) {
dst_ref.obj->section_flags[associated_section->data-1] |= COFF_SectionFlag_LnkRemove;
}
}
// merge symbol refs
LNK_ObjSymbolRefNode *src_last_ref;
for (src_last_ref = src->refs; src_last_ref->next != 0; src_last_ref = src_last_ref->next);
src_last_ref->next = dst->refs;
// assert leader section is live
#if BUILD_DEBUG
{
COFF_ParsedSymbol src_parsed = lnk_parsed_from_symbol(src);
COFF_SymbolValueInterpType src_interp = lnk_interp_from_symbol(src);
LNK_ObjSymbolRef src_ref = lnk_ref_from_symbol(src);
if (src_interp == COFF_SymbolValueInterp_Regular) {
AssertAlways(~src_ref.obj->section_flags[src_parsed.section_number-1] & COFF_SectionFlag_LnkRemove);
}
}
#endif
}
internal void
lnk_symbol_hash_trie_insert_or_replace(Arena *arena,
LNK_SymbolHashTrieChunkList *chunks,
LNK_SymbolHashTrie **trie,
U64 hash,
LNK_Symbol *symbol)
{
LNK_SymbolHashTrie **curr_trie_ptr = trie;
for (U64 h = hash; ; h <<= 2) {
// load current pointer
LNK_SymbolHashTrie *curr_trie = ins_atomic_ptr_eval(curr_trie_ptr);
if (curr_trie == 0) {
// init node
LNK_SymbolHashTrie *new_trie = lnk_symbol_hash_trie_chunk_list_push(arena, chunks, 0x1000);
new_trie->name = &symbol->name;
new_trie->symbol = symbol;
MemoryZeroArray(new_trie->child);
// try to insert new node
LNK_SymbolHashTrie *cmp = ins_atomic_ptr_eval_cond_assign(curr_trie_ptr, new_trie, curr_trie);
// was symbol inserted?
if (cmp == curr_trie) {
break;
}
// rollback chunk list push
--chunks->last->count;
// retry insert with trie node from another thread
curr_trie = cmp;
}
// load current symbol
String8 *curr_name = ins_atomic_ptr_eval(&curr_trie->name);
if (curr_name && str8_match(*curr_name, symbol->name, 0)) {
for (LNK_Symbol *src = symbol;;) {
// try replacing current symbol with zero, otherwise loop back and retry
LNK_Symbol *leader = ins_atomic_ptr_eval_assign(&curr_trie->symbol, 0);
// apply replacement
if (leader) {
if (lnk_can_replace_symbol(leader, src)) {
// discard leader
lnk_on_symbol_replace(leader, src);
leader = src;
} else {
// discard source
lnk_on_symbol_replace(src, leader);
src = leader;
}
} else {
leader = src;
}
// try replacing symbol, if another thread has already taken the slot, rerun replacement loop again
LNK_Symbol *was_replaced = ins_atomic_ptr_eval_cond_assign(&curr_trie->symbol, leader, 0);
// symbol replaced, exit
if (was_replaced == 0) {
goto exit;
}
}
}
// pick child and descend
curr_trie_ptr = curr_trie->child + (h >> 62);
}
exit:;
}
internal LNK_SymbolHashTrie *
lnk_symbol_hash_trie_search(LNK_SymbolHashTrie *trie, U64 hash, String8 name)
{
LNK_SymbolHashTrie *result = 0;
LNK_SymbolHashTrie **curr_ptr = &trie;
for (U64 h = hash; ; h <<= 2) {
LNK_SymbolHashTrie *curr = ins_atomic_ptr_eval(curr_ptr);
if (curr == 0) {
break;
}
if (curr->name && str8_match(*curr->name, name, 0)) {
result = curr;
break;
}
curr_ptr = curr->child + (h >> 62);
}
return result;
}
internal void
lnk_symbol_hash_trie_remove(LNK_SymbolHashTrie *trie)
{
ins_atomic_ptr_eval_assign(&trie->name, 0);
ins_atomic_ptr_eval_assign(&trie->symbol, 0);
}
internal LNK_SymbolHashTrieChunk **
lnk_array_from_symbol_hash_trie_chunk_list(Arena *arena, LNK_SymbolHashTrieChunkList *lists, U64 lists_count, U64 *count_out)
{
U64 chunks_count = 0;
for EachIndex(i, lists_count) { chunks_count += lists[i].count; }
LNK_SymbolHashTrieChunk **chunks = push_array(arena, LNK_SymbolHashTrieChunk *, chunks_count);
U64 chunks_cursor = 0;
for EachIndex(i, lists_count) {
for (LNK_SymbolHashTrieChunk *chunk = lists[i].first; chunk != 0; chunk = chunk->next) {
chunks[chunks_cursor++] = chunk;
}
}
if (count_out) {
*count_out = chunks_count;
}
return chunks;
}
internal LNK_ObjSymbolRef
lnk_ref_from_symbol(LNK_Symbol *symbol)
{
return symbol->refs->v;
}
internal U64
lnk_ref_count_from_symbol(LNK_Symbol *symbol)
{
U64 count = 0;
for (LNK_ObjSymbolRefNode *node = symbol->refs; node != 0; node = node->next, count += 1);
return count;
}
internal LNK_ObjSymbolRef **
lnk_ref_from_symbol_many(Arena *arena, LNK_Symbol *symbol, U64 *count_out)
{
// TODO: would be simpler if we sorted refs on insert/update
U64 refs_count = lnk_ref_count_from_symbol(symbol);
LNK_ObjSymbolRef **refs = push_array(arena, LNK_ObjSymbolRef *, refs_count);
U64 i = 0;
for (LNK_ObjSymbolRefNode *node = symbol->refs; node != 0; node = node->next, i += 1) {
refs[i] = &node->v;
}
radsort(refs, refs_count, lnk_obj_symbol_ref_ptr_is_before);
if (count_out) {
*count_out = refs_count;
}
return refs;
}
internal COFF_ParsedSymbol
lnk_parsed_from_symbol(LNK_Symbol *symbol)
{
LNK_ObjSymbolRef ref = lnk_ref_from_symbol(symbol);
return lnk_parsed_symbol_from_coff_symbol_idx(ref.obj, ref.symbol_idx);
}
internal COFF_SymbolValueInterpType
lnk_interp_from_symbol(LNK_Symbol *symbol)
{
COFF_ParsedSymbol symbol_parsed = lnk_parsed_from_symbol(symbol);
return coff_interp_from_parsed_symbol(symbol_parsed);
}
internal U64
lnk_symbol_table_hasher(String8 string)
{
return u64_hash_from_str8(string);
}
internal LNK_SymbolTable *
lnk_symbol_table_init(TP_Arena *arena)
{
LNK_SymbolTable *symtab = push_array(arena->v[0], LNK_SymbolTable, 1);
symtab->arena = arena;
symtab->chunks = push_array(arena->v[0], LNK_SymbolHashTrieChunkList, arena->count);
symtab->search_chunks = push_array(arena->v[0], LNK_SymbolHashTrieChunkList, arena->count);
return symtab;
}
internal void
lnk_symbol_table_push_(LNK_SymbolTable *symtab, Arena *arena, U64 worker_id, LNK_Symbol *symbol)
{
U64 hash = lnk_symbol_table_hasher(symbol->name);
COFF_SymbolValueInterpType interp = lnk_interp_from_symbol(symbol);
LNK_SymbolHashTrieChunkList *chunks;
if (interp == COFF_SymbolValueInterp_Weak || interp == COFF_SymbolValueInterp_Undefined) {
chunks = &symtab->search_chunks[worker_id];
} else {
chunks = &symtab->chunks[worker_id];
}
lnk_symbol_hash_trie_insert_or_replace(arena, chunks, &symtab->root, hash, symbol);
}
internal void
lnk_symbol_table_push(LNK_SymbolTable *symtab, LNK_Symbol *symbol)
{
lnk_symbol_table_push_(symtab, symtab->arena->v[0], 0, symbol);
}
internal LNK_SymbolHashTrie *
lnk_symbol_table_search_(LNK_SymbolTable *symtab, String8 name)
{
U64 hash = lnk_symbol_table_hasher(name);
return lnk_symbol_hash_trie_search(symtab->root, hash, name);
}
internal LNK_Symbol *
lnk_symbol_table_search(LNK_SymbolTable *symtab, String8 name)
{
LNK_SymbolHashTrie *trie = lnk_symbol_table_search_(symtab, name);
return trie ? trie->symbol : 0;
}
internal LNK_Symbol *
lnk_symbol_table_searchf(LNK_SymbolTable *symtab, char *fmt, ...)
{
Temp scratch = scratch_begin(0, 0);
va_list args; va_start(args, fmt);
String8 name = push_str8fv(scratch.arena, fmt, args);
va_end(args);
LNK_Symbol *symbol = lnk_symbol_table_search(symtab, name);
scratch_end(scratch);
return symbol;
}
internal ISectOff
lnk_sc_from_symbol(LNK_Symbol *symbol)
{
COFF_ParsedSymbol parsed_symbol = lnk_parsed_from_symbol(symbol);
ISectOff sc = { .isect = parsed_symbol.section_number, .off = parsed_symbol.value };
return sc;
}
internal U64
lnk_voff_from_symbol(COFF_SectionHeader **image_section_table, LNK_Symbol *symbol)
{
ISectOff sc = lnk_sc_from_symbol(symbol);
U64 voff = image_section_table[sc.isect]->voff + sc.off;
return voff;
}
internal U64
lnk_foff_from_symbol(COFF_SectionHeader **image_section_table, LNK_Symbol *symbol)
{
ISectOff sc = lnk_sc_from_symbol(symbol);
U64 foff = image_section_table[sc.isect]->foff + sc.off;
return foff;
}
internal B32
lnk_resolve_weak_symbol(LNK_SymbolTable *symtab, LNK_ObjSymbolRef symbol, LNK_ObjSymbolRef *resolved_symbol_out)
{
Temp scratch = scratch_begin(0,0);
B32 is_resolved = 0;
struct S { struct S *next; LNK_ObjSymbolRef symbol; B32 is_anti_dep; };
struct S *sf = 0, *sl = 0;
LNK_ObjSymbolRef current_symbol = symbol;
for (;;) {
// guard against self-referencing weak symbols
struct S *was_visited = 0;
for (struct S *s = sf; s != 0; s = s->next) {
if (MemoryCompare(&s->symbol, &current_symbol, sizeof(LNK_ObjSymbolRef)) == 0) { was_visited = s; break; }
}
if (was_visited) {
String8List chain = {0};
for (struct S *s = sf; s != 0; s = s->next) {
COFF_ParsedSymbol s_parsed = lnk_parsed_symbol_from_coff_symbol_idx(s->symbol.obj, s->symbol.symbol_idx);
str8_list_pushf(scratch.arena, &chain, "\t%S Symbol %S (No. %#x) =>", s->symbol.obj->path, s_parsed.name, s->symbol.symbol_idx);
}
COFF_ParsedSymbol symbol_parsed = lnk_parsed_symbol_from_coff_symbol_idx(symbol.obj, symbol.symbol_idx);
str8_list_pushf(scratch.arena, &chain, "\t%S Symbol %S (No. %#x)", sf->symbol.obj->path, symbol_parsed.name, sf->symbol.symbol_idx);
String8 chain_string = str8_list_join(scratch.arena, &chain, &(StringJoin){ .sep = str8_lit("\n") });
lnk_error_obj(LNK_Error_WeakCycle, symbol.obj, "unable to resolve cyclic symbol %S; ref chain:\n%S", symbol_parsed.name, chain_string);
goto exit;
}
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) {
// record visited symbol
struct S *s = push_array(scratch.arena, struct S, 1);
s->symbol = current_symbol;
SLLQueuePush(sf, sl, s);
// does weak symbol have a definition?
LNK_Symbol *defn_symbol = lnk_symbol_table_search(symtab, current_parsed.name);
COFF_ParsedSymbol defn_parsed = lnk_parsed_from_symbol(defn_symbol);
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 = lnk_ref_from_symbol(defn_symbol);
break;
}
COFF_SymbolWeakExt *weak_ext = coff_parse_weak_tag(current_parsed, current_symbol.obj->header.is_big_obj);
// no definition -- fallback to default symbol
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_ObjSymbolRef){ .obj = current_symbol.obj, .symbol_idx = weak_ext->tag_index };
if (weak_ext->characteristics == COFF_WeakExt_AntiDependency) {
if (tag_interp == COFF_SymbolValueInterp_Undefined || tag_interp == COFF_SymbolValueInterp_Weak) {
LNK_Symbol *dep_symbol = lnk_symbol_table_search(symtab, tag_parsed.name);
tag_interp = lnk_interp_from_symbol(dep_symbol);
}
if (tag_interp == COFF_SymbolValueInterp_Weak) { break; }
}
} else if (current_interp == COFF_SymbolValueInterp_Undefined) {
LNK_Symbol *defn_symbol = lnk_symbol_table_search(symtab, current_parsed.name);
COFF_SymbolValueInterpType defn_interp = lnk_interp_from_symbol(defn_symbol);
// unresolved undefined symbol
if (defn_interp == COFF_SymbolValueInterp_Undefined) { break; }
// follow symbol definition
current_symbol = lnk_ref_from_symbol(defn_symbol);
} else { break; }
}
if (resolved_symbol_out) {
*resolved_symbol_out = current_symbol;
}
is_resolved = 1;
exit:;
scratch_end(scratch);
return is_resolved;
}
internal B32
lnk_resolve_symbol(LNK_SymbolTable *symtab, LNK_ObjSymbolRef symbol, LNK_ObjSymbolRef *symbol_out)
{
B32 is_resolved = 1;
COFF_ParsedSymbol symbol_parsed = lnk_parsed_symbol_from_coff_symbol_idx(symbol.obj, symbol.symbol_idx);
COFF_SymbolValueInterpType symbol_interp = coff_interp_symbol(symbol_parsed.section_number, symbol_parsed.value, symbol_parsed.storage_class);
switch (symbol_interp) {
case COFF_SymbolValueInterp_Regular: {
LNK_Symbol *symlink = lnk_obj_get_comdat_symlink(symbol.obj, symbol_parsed.section_number);
*symbol_out = symlink ? lnk_ref_from_symbol(symlink) : symbol;
} break;
case COFF_SymbolValueInterp_Weak: {
LNK_Symbol *defn = lnk_symbol_table_search(symtab, symbol_parsed.name);
COFF_ParsedSymbol defn_parsed = lnk_parsed_from_symbol(defn);
COFF_SymbolValueInterpType defn_interp = lnk_interp_from_symbol(defn);
if (defn_interp != COFF_SymbolValueInterp_Undefined) {
*symbol_out = lnk_ref_from_symbol(defn);
} else {
is_resolved = 0;
}
} break;
case COFF_SymbolValueInterp_Undefined: {
LNK_Symbol *defn = lnk_symbol_table_search(symtab, symbol_parsed.name);
if (defn) {
*symbol_out = lnk_ref_from_symbol(defn);
} else {
is_resolved = 0;
}
} break;
case COFF_SymbolValueInterp_Common: {
LNK_Symbol *defn = lnk_symbol_table_search(symtab, symbol_parsed.name);
*symbol_out = lnk_ref_from_symbol(defn);
} break;
case COFF_SymbolValueInterp_Abs: {
if (symbol_parsed.storage_class == COFF_SymStorageClass_External) {
LNK_Symbol *defn = lnk_symbol_table_search(symtab, symbol_parsed.name);
*symbol_out = lnk_ref_from_symbol(defn);
} else {
*symbol_out = symbol;
}
} break;
case COFF_SymbolValueInterp_Debug: { *symbol_out = symbol; } break;
}
return is_resolved;
}
internal
THREAD_POOL_TASK_FUNC(lnk_replace_weak_with_default_symbol_task)
{
LNK_SymbolTable *symtab = raw_task;
for EachNode(c, LNK_SymbolHashTrieChunk, symtab->search_chunks[task_id].first) {
for EachIndex(i, c->count) {
LNK_Symbol *symbol = c->v[i].symbol;
LNK_ObjSymbolRef symbol_ref = lnk_ref_from_symbol(symbol);
COFF_ParsedSymbol symbol_parsed = lnk_parsed_from_symbol(symbol);
COFF_SymbolValueInterpType symbol_interp = coff_interp_from_parsed_symbol(symbol_parsed);
if (symbol_interp == COFF_SymbolValueInterp_Weak) {
LNK_ObjSymbolRef resolve = {0};
if (lnk_resolve_weak_symbol(symtab, symbol_ref, &resolve)) {
COFF_ParsedSymbol resolve_parsed = lnk_parsed_symbol_from_coff_symbol_idx(resolve.obj, resolve.symbol_idx);
COFF_SymbolValueInterpType resolve_interp = coff_interp_from_parsed_symbol(resolve_parsed);
if (resolve_interp == COFF_SymbolValueInterp_Weak) {
COFF_SymbolWeakExt *weak_ext = coff_parse_weak_tag(resolve_parsed, symbol_ref.obj->header.is_big_obj);
if (symbol_ref.obj->header.is_big_obj) {
COFF_Symbol32 *symbol32 = symbol_parsed.raw_symbol;
symbol32->section_number = COFF_Symbol_UndefinedSection;
symbol32->value = 0;
symbol32->storage_class = COFF_SymStorageClass_External;
} else {
COFF_Symbol16 *symbol16 = symbol_parsed.raw_symbol;
symbol16->section_number = COFF_Symbol_UndefinedSection;
symbol16->value = 0;
symbol16->storage_class = COFF_SymStorageClass_External;
}
} else {
symbol->refs->v = resolve;
}
}
}
}
}
}
internal void
lnk_replace_weak_with_default_symbols(TP_Context *tp, LNK_SymbolTable *symtab)
{
ProfBeginFunction();
tp_for_parallel_prof(tp, 0, tp->worker_count, lnk_replace_weak_with_default_symbol_task, symtab, "Replace Weak With Default Symbols");
for EachIndex(i, tp->worker_count) {
lnk_symbol_hash_trie_chunk_list_concat_in_place(&symtab->chunks[i], &symtab->search_chunks[i]);
}
ProfEnd();
}
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