X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fcommon.cc;h=b1348ecfbc7f3396a77451a28af1d8192fdc0779;hb=348fe36b1d64f12c60e08f6313520b3191663063;hp=4bc6a51d6984a7a1474aa1219573ec60c16ca0c5;hpb=f5c870d25d59bc1e6fcb6a836b6bd1981788982c;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/common.cc b/gold/common.cc index 4bc6a51d69..b1348ecfbc 100644 --- a/gold/common.cc +++ b/gold/common.cc @@ -1,6 +1,6 @@ // common.cc -- handle common symbols for gold -// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. +// Copyright (C) 2006-2020 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -36,24 +36,21 @@ namespace gold // Allocate_commons_task methods. -// This task allocates the common symbols. We need a lock on the -// symbol table. +// This task allocates the common symbols. We arrange to run it +// before anything else which needs to access the symbol table. Task_token* Allocate_commons_task::is_runnable() { - if (!this->symtab_lock_->is_writable()) - return this->symtab_lock_; return NULL; } -// Return the locks we hold: one on the symbol table, and one blocker. +// Release a blocker. void Allocate_commons_task::locks(Task_locker* tl) { tl->add(this, this->blocker_); - tl->add(this, this->symtab_lock_); } // Allocate the common symbols. @@ -64,21 +61,26 @@ Allocate_commons_task::run(Workqueue*) this->symtab_->allocate_commons(this->layout_, this->mapfile_); } -// This class is used to sort the common symbol by size. We put the -// larger common symbols first. +// This class is used to sort the common symbol. We normally put the +// larger common symbols first. This can be changed by using +// --sort-commons, which tells the linker to sort by alignment. template class Sort_commons { public: - Sort_commons(const Symbol_table* symtab) - : symtab_(symtab) + Sort_commons(const Symbol_table* symtab, + Symbol_table::Sort_commons_order sort_order) + : symtab_(symtab), sort_order_(sort_order) { } bool operator()(const Symbol* a, const Symbol* b) const; private: + // The symbol table. const Symbol_table* symtab_; + // How to sort. + Symbol_table::Sort_commons_order sort_order_; }; template @@ -94,22 +96,48 @@ Sort_commons::operator()(const Symbol* pa, const Symbol* pb) const const Sized_symbol* psa = symtab->get_sized_symbol(pa); const Sized_symbol* psb = symtab->get_sized_symbol(pb); - // Sort by largest size first. + // The size. typename Sized_symbol::Size_type sa = psa->symsize(); typename Sized_symbol::Size_type sb = psb->symsize(); + + // The alignment. + typename Sized_symbol::Value_type aa = psa->value(); + typename Sized_symbol::Value_type ab = psb->value(); + + if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_DESCENDING) + { + if (aa < ab) + return false; + else if (ab < aa) + return true; + } + else if (this->sort_order_ + == Symbol_table::SORT_COMMONS_BY_ALIGNMENT_ASCENDING) + { + if (aa < ab) + return true; + else if (ab < aa) + return false; + } + else + gold_assert(this->sort_order_ + == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING); + + // Sort by descending size. if (sa < sb) return false; else if (sb < sa) return true; - // When the symbols are the same size, we sort them by alignment, - // largest alignment first. - typename Sized_symbol::Value_type va = psa->value(); - typename Sized_symbol::Value_type vb = psb->value(); - if (va < vb) - return false; - else if (vb < va) - return true; + if (this->sort_order_ == Symbol_table::SORT_COMMONS_BY_SIZE_DESCENDING) + { + // When the symbols are the same size, we sort them by + // alignment, largest alignment first. + if (aa < ab) + return false; + else if (ab < aa) + return true; + } // Otherwise we stabilize the sort by sorting by name. return strcmp(psa->name(), psb->name()) < 0; @@ -120,10 +148,27 @@ Sort_commons::operator()(const Symbol* pa, const Symbol* pb) const void Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile) { + Sort_commons_order sort_order; + if (!parameters->options().user_set_sort_common()) + sort_order = SORT_COMMONS_BY_SIZE_DESCENDING; + else + { + const char* order = parameters->options().sort_common(); + if (*order == '\0' || strcmp(order, "descending") == 0) + sort_order = SORT_COMMONS_BY_ALIGNMENT_DESCENDING; + else if (strcmp(order, "ascending") == 0) + sort_order = SORT_COMMONS_BY_ALIGNMENT_ASCENDING; + else + { + gold_error("invalid --sort-common argument: %s", order); + sort_order = SORT_COMMONS_BY_SIZE_DESCENDING; + } + } + if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) - this->do_allocate_commons<32>(layout, mapfile); + this->do_allocate_commons<32>(layout, mapfile, sort_order); #else gold_unreachable(); #endif @@ -131,7 +176,7 @@ Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile) else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) - this->do_allocate_commons<64>(layout, mapfile); + this->do_allocate_commons<64>(layout, mapfile, sort_order); #else gold_unreachable(); #endif @@ -144,20 +189,25 @@ Symbol_table::allocate_commons(Layout* layout, Mapfile* mapfile) template void -Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile) +Symbol_table::do_allocate_commons(Layout* layout, Mapfile* mapfile, + Sort_commons_order sort_order) { if (!this->commons_.empty()) this->do_allocate_commons_list(layout, COMMONS_NORMAL, - &this->commons_, mapfile); + &this->commons_, mapfile, + sort_order); if (!this->tls_commons_.empty()) this->do_allocate_commons_list(layout, COMMONS_TLS, - &this->tls_commons_, mapfile); + &this->tls_commons_, mapfile, + sort_order); if (!this->small_commons_.empty()) this->do_allocate_commons_list(layout, COMMONS_SMALL, - &this->small_commons_, mapfile); + &this->small_commons_, mapfile, + sort_order); if (!this->large_commons_.empty()) this->do_allocate_commons_list(layout, COMMONS_LARGE, - &this->large_commons_, mapfile); + &this->large_commons_, mapfile, + sort_order); } // Allocate the common symbols in a list. IS_TLS indicates whether @@ -169,11 +219,9 @@ Symbol_table::do_allocate_commons_list( Layout* layout, Commons_section_type commons_section_type, Commons_type* commons, - Mapfile* mapfile) + Mapfile* mapfile, + Sort_commons_order sort_order) { - typedef typename Sized_symbol::Value_type Value_type; - typedef typename Sized_symbol::Size_type Size_type; - // We've kept a list of all the common symbols. But the symbol may // have been resolved to a defined symbol by now. And it may be a // forwarder. First remove all non-common symbols. @@ -202,10 +250,9 @@ Symbol_table::do_allocate_commons_list( if (!any) return; - // Sort the common symbols by size, so that they pack better into - // memory. + // Sort the common symbols. std::sort(commons->begin(), commons->end(), - Sort_commons(this)); + Sort_commons(this, sort_order)); // Place them in a newly allocated BSS section. elfcpp::Elf_Xword flags = elfcpp::SHF_WRITE | elfcpp::SHF_ALLOC; @@ -236,10 +283,23 @@ Symbol_table::do_allocate_commons_list( gold_unreachable(); } - Output_data_space *poc = new Output_data_space(addralign, ds_name); - Output_section *os = layout->add_output_section_data(name, - elfcpp::SHT_NOBITS, - flags, poc, false); + Output_data_space* poc; + Output_section* os; + + if (!parameters->incremental_update()) + { + poc = new Output_data_space(addralign, ds_name); + os = layout->add_output_section_data(name, elfcpp::SHT_NOBITS, flags, + poc, ORDER_INVALID, false); + } + else + { + // When doing an incremental update, we need to allocate each common + // directly from the output section's free list. + poc = NULL; + os = layout->find_output_section(name); + } + if (os != NULL) { if (commons_section_type == COMMONS_SMALL) @@ -258,6 +318,17 @@ Symbol_table::do_allocate_commons_list( Symbol* sym = *p; if (sym == NULL) break; + + // Because we followed forwarding symbols above, but we didn't + // do it reliably before adding symbols to the list, it is + // possible for us to have the same symbol on the list twice. + // This can happen in the horrible case where a program defines + // a common symbol with the same name as a versioned libc + // symbol. That will show up here as a symbol which has already + // been allocated and is therefore no longer a common symbol. + if (!sym->is_common()) + continue; + Sized_symbol* ssym = this->get_sized_symbol(sym); // Record the symbol in the map file now, before we change its @@ -266,12 +337,26 @@ Symbol_table::do_allocate_commons_list( if (mapfile != NULL) mapfile->report_allocate_common(sym, ssym->symsize()); - off = align_address(off, ssym->value()); - ssym->allocate_common(poc, off); - off += ssym->symsize(); + if (poc != NULL) + { + off = align_address(off, ssym->value()); + ssym->allocate_common(poc, off); + off += ssym->symsize(); + } + else + { + // For an incremental update, allocate from the free list. + off = os->allocate(ssym->symsize(), ssym->value()); + if (off == -1) + gold_fallback(_("out of patch space in section %s; " + "relink with --incremental-full"), + os->name()); + ssym->allocate_common(os, off); + } } - poc->set_current_data_size(off); + if (poc != NULL) + poc->set_current_data_size(off); commons->clear(); }