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libLTO has a bug in that it will keep every symbol if none is needed. We used 

to hack around this in the gold plugin by deleting a module if no symbol was
needed. Unfortunately, the hack is wrong in the case of o module having no
visible symbols but still having side effects via static constructors.

The bug will have to be fixed in libLTO itself.

llvm-svn: 166745
This commit is contained in:
Rafael Espindola 2012-10-26 00:29:57 +00:00
parent 5ee5ca1dbc
commit a339e47689
1 changed files with 0 additions and 10 deletions
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10
llvm/tools/gold/gold-plugin.cpp
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@ -378,9 +378,6 @@ static ld_plugin_status all_symbols_read_hook(void) {
} }
} }
// If we don't preserve any symbols, libLTO will assume that all symbols are
// needed. Keep all symbols unless we're producing a final executable.
bool anySymbolsPreserved = false;
for (std::list<claimed_file>::iterator I = Modules.begin(), for (std::list<claimed_file>::iterator I = Modules.begin(),
E = Modules.end(); I != E; ++I) { E = Modules.end(); I != E; ++I) {
if (I->syms.empty()) if (I->syms.empty())
@ -389,7 +386,6 @@ static ld_plugin_status all_symbols_read_hook(void) {
for (unsigned i = 0, e = I->syms.size(); i != e; i++) { for (unsigned i = 0, e = I->syms.size(); i != e; i++) {
if (I->syms[i].resolution == LDPR_PREVAILING_DEF) { if (I->syms[i].resolution == LDPR_PREVAILING_DEF) {
lto_codegen_add_must_preserve_symbol(code_gen, I->syms[i].name); lto_codegen_add_must_preserve_symbol(code_gen, I->syms[i].name);
anySymbolsPreserved = true;
if (options::generate_api_file) if (options::generate_api_file)
api_file << I->syms[i].name << "\n"; api_file << I->syms[i].name << "\n";
@ -400,12 +396,6 @@ static ld_plugin_status all_symbols_read_hook(void) {
if (options::generate_api_file) if (options::generate_api_file)
api_file.close(); api_file.close();
if (!anySymbolsPreserved) {
// All of the IL is unnecessary!
lto_codegen_dispose(code_gen);
return LDPS_OK;
}
lto_codegen_set_pic_model(code_gen, output_type); lto_codegen_set_pic_model(code_gen, output_type);
lto_codegen_set_debug_model(code_gen, LTO_DEBUG_MODEL_DWARF); lto_codegen_set_debug_model(code_gen, LTO_DEBUG_MODEL_DWARF);
if (!options::mcpu.empty()) if (!options::mcpu.empty())