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authorSriraman Tallam <tmsriram@google.com>2009-01-28 02:25:33 +0000
committerSriraman Tallam <tmsriram@google.com>2009-01-28 02:25:33 +0000
commit6d03d481a0827abf92804f8ffaf9ab00593943be (patch)
tree617f1054036bd3cca35f897b225b37b4ce1a3b0c /gold/reloc.cc
parent7df3ce47694f5c804a9468d4c098825b5901216e (diff)
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2009-01-20 Sriraman Tallam <tmsriram@google.com>
* Makefile.am (CCFILES): Add gc.cc. (HFILES): Add gc.h. * Makefile.in: Regenerate. * gold.cc (Gc_runner): New class. (queue_initial_tasks): Call garbage collection related tasks when corresponding options are invoked. (queue_middle_gc_tasks): New function. (queue_middle_tasks): Reorder tasks to allow relocs to be read and processed early before laying out sections during garbage collection. * gold.h (queue_middle_gc_tasks): New function. (is_prefix_of): Move from "layout.cc". * i386.cc (Target_i386::gc_process_relocs): New function. * layout.cc (is_prefix_of): Remove. Move to "gold.h" * main.cc (main): Create object of class "Garbage_collection". * object.cc (Relobj::copy_symbols_data): New function. (Relobj::is_section_name_included): New function. (Sized_relobj::do_layout): Allow this function to be called twice during garbage collection and defer layout of section during the first call. * object.h (Relobj::get_symbols_data): New function. (Relobj::is_section_name_included): New function. (Relobj::copy_symbols_data): New function. (Relobj::set_symbols_data): New function. (Relobj::get_relocs_data): New function. (Relobj::set_relocs_data): New function. (Relobj::is_output_section_offset_invalid): New pure virtual function. (Relobj::gc_process_relocs): New function. (Relobj::do_gc_process_relocs): New pure virtual function. (Relobj::sd_): New data member. (Sized_relobj::is_output_section_offset_invalid): New function. (Sized_relobj::do_gc_process_relocs): New function. * options.h (General_options::gc_sections): Modify to not be a no-op. (General_options::print_gc_sections): New option. * plugin.cc (Plugin_finish::run): Remove function call to Plugin_manager::layout_deferred_objects. Move it to "gold.cc". * powerpc.cc (Target_powerpc::gc_process_relocs): New function. * reloc.cc (Read_relocs::run): Add task to process relocs and determine unreferenced sections when doing garbage collection. (Gc_process_relocs): New class. (Sized_relobj::do_gc_process_relocs): New function. (Sized_relobj::do_scan_relocs): Don't try to scan the relocs for sections that are garbage collected. * reloc.h (Gc_process_relocs): New class. * sparc.cc (Target_sparc::gc_process_relocs): New function. * symtab.cc (Symbol::should_add_dynsym_entry): Do not add entries for symbols whose corresponding sections are garbage collected. (Symbol_table::Symbol_table): Add new parameter for the garbage collection object. (Symbol_table::gc_mark_undef_symbols): New function. (Symbol_table::gc_mark_symbol_for_shlib): New function. (Symbol_table::gc_mark_dyn_syms): New function. (Symbol_table::resolve): Do not treat symbols seen in dynamic objects as garbage. (Symbol_table::add_from_object): Likewise. (Symbol_table::add_from_relobj): When building shared objects, do not treat externally visible symbols as garbage. (Symbol_table::sized_finalize_symbol): Do not check dynamic symbol table information for static and relocatable links. * symtab.h (Symbol_table::set_gc): New function. (Symbol_table::gc): New function. (Symbol_table::gc_mark_undef_symbols): New function. (Symbol_table::gc_mark_symbol_for_shlib): New function. (Symbol_table::gc_mark_dyn_syms): New function. (Symbol_table::gc_): New data member. * target.h (Sized_target::gc_process_relocs): New pure virtual function. * x86_64.cc (Target_x86_64::gc_process_relocs): New function. * testsuite/testfile.cc (Target_test::gc_process_relocs): New function.
Diffstat (limited to 'gold/reloc.cc')
-rw-r--r--gold/reloc.cc147
1 files changed, 143 insertions, 4 deletions
diff --git a/gold/reloc.cc b/gold/reloc.cc
index f6bef1d..669d87b 100644
--- a/gold/reloc.cc
+++ b/gold/reloc.cc
@@ -1,6 +1,6 @@
// reloc.cc -- relocate input files for gold.
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
@@ -62,11 +62,28 @@ Read_relocs::run(Workqueue* workqueue)
{
Read_relocs_data *rd = new Read_relocs_data;
this->object_->read_relocs(rd);
+ this->object_->set_relocs_data(rd);
this->object_->release();
- workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
- this->layout_, this->object_, rd,
- this->symtab_lock_, this->blocker_));
+ // If garbage collection is desired, we must process the relocs
+ // instead of scanning the relocs as reloc processing is necessary
+ // to determine unused sections.
+ if (parameters->options().gc_sections())
+ {
+ workqueue->queue_next(new Gc_process_relocs(this->options_,
+ this->symtab_,
+ this->layout_,
+ this->object_, rd,
+ this->symtab_lock_,
+ this->blocker_));
+ }
+ else
+ {
+ workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
+ this->layout_, this->object_, rd,
+ this->symtab_lock_,
+ this->blocker_));
+ }
}
// Return a debugging name for the task.
@@ -77,6 +94,43 @@ Read_relocs::get_name() const
return "Read_relocs " + this->object_->name();
}
+// Gc_process_relocs methods.
+
+// These tasks process the relocations read by Read_relocs and
+// determine which sections are referenced and which are garbage.
+// This task is done only when --gc-sections is used.
+
+Task_token*
+Gc_process_relocs::is_runnable()
+{
+ if (this->object_->is_locked())
+ return this->object_->token();
+ return NULL;
+}
+
+void
+Gc_process_relocs::locks(Task_locker* tl)
+{
+ tl->add(this, this->object_->token());
+ tl->add(this, this->blocker_);
+}
+
+void
+Gc_process_relocs::run(Workqueue*)
+{
+ this->object_->gc_process_relocs(this->options_, this->symtab_, this->layout_,
+ this->rd_);
+ this->object_->release();
+}
+
+// Return a debugging name for the task.
+
+std::string
+Gc_process_relocs::get_name() const
+{
+ return "Gc_process_relocs " + this->object_->name();
+}
+
// Scan_relocs methods.
// These tasks scan the relocations read by Read_relocs and mark up
@@ -296,6 +350,47 @@ Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
}
}
+// Process the relocs to generate mappings from source sections to referenced
+// sections. This is used during garbage colletion to determine garbage
+// sections.
+
+template<int size, bool big_endian>
+void
+Sized_relobj<size, big_endian>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd)
+{
+ Sized_target<size, big_endian>* target = this->sized_target();
+
+ const unsigned char* local_symbols;
+ if (rd->local_symbols == NULL)
+ local_symbols = NULL;
+ else
+ local_symbols = rd->local_symbols->data();
+
+ for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
+ p != rd->relocs.end();
+ ++p)
+ {
+ if (!parameters->options().relocatable())
+ {
+ // As noted above, when not generating an object file, we
+ // only scan allocated sections. We may see a non-allocated
+ // section here if we are emitting relocs.
+ if (p->is_data_section_allocated)
+ target->gc_process_relocs(options, symtab, layout, this,
+ p->data_shndx, p->sh_type,
+ p->contents->data(), p->reloc_count,
+ p->output_section,
+ p->needs_special_offset_handling,
+ this->local_symbol_count_,
+ local_symbols);
+ }
+ }
+}
+
+
// Scan the relocs and adjust the symbol table. This looks for
// relocations which require GOT/PLT/COPY relocations.
@@ -318,6 +413,14 @@ Sized_relobj<size, big_endian>::do_scan_relocs(const General_options& options,
p != rd->relocs.end();
++p)
{
+ // When garbage collection is on, unreferenced sections are not included
+ // in the link that would have been included normally. This is known only
+ // after Read_relocs hence this check has to be done again.
+ if (parameters->options().gc_sections())
+ {
+ if (p->output_section == NULL)
+ continue;
+ }
if (!parameters->options().relocatable())
{
// As noted above, when not generating an object file, we
@@ -1080,6 +1183,42 @@ Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
#ifdef HAVE_TARGET_32_LITTLE
template
void
+Sized_relobj<32, false>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+void
+Sized_relobj<32, true>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+void
+Sized_relobj<64, false>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+void
+Sized_relobj<64, true>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_32_LITTLE
+template
+void
Sized_relobj<32, false>::do_scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,