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authorSriraman Tallam <tmsriram@google.com>2012-08-24 18:35:35 +0000
committerSriraman Tallam <tmsriram@google.com>2012-08-24 18:35:35 +0000
commit16164a6b00372ebc0360f6aa71337e5613278817 (patch)
tree503893149fa2b29775eafe985a0a537cf7433132 /gold
parent92a289b3800274d15d440cea98c0df067da4c2ec (diff)
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Patch adds support to allow plugins to map selected subset of sections to unique
segments. 2012-08-24 Sriraman Tallam <tmsriram@google.com> * gold.cc (queue_middle_tasks): Call layout again when unique segments for sections is desired. * layout.cc (Layout::Layout): Initialize new members. (Layout::get_output_section_flags): New function. (Layout::choose_output_section): Call get_output_section_flags. (Layout::layout): Make output section for mapping to a unique segment. (Layout::insert_section_segment_map): New function. (Layout::attach_allocated_section_to_segment): Make unique segment for output sections marked so. (Layout::segment_precedes): Check for unique segments when sorting. * layout.h (Layout::Unique_segment_info): New struct. (Layout::Section_segment_map): New typedef. (Layout::insert_section_segment_map): New function. (Layout::get_output_section_flags): New function. (Layout::is_unique_segment_for_sections_specified): New function. (Layout::set_unique_segment_for_sections_specified): New function. (Layout::unique_segment_for_sections_specified_): New member. (Layout::section_segment_map_): New member. * object.cc (Sized_relobj_file<size, big_endian>::do_layout): Rename is_gc_pass_one to is_pass_one. Rename is_gc_pass_two to is_pass_two. Rename is_gc_or_icf to is_two_pass. Check for which pass based on whether symbols data is present. Make it two pass when unique segments for sections is desired. * output.cc (Output_section::Output_section): Initialize new members. * output.h (Output_section::is_unique_segment): New function. (Output_section::set_is_unique_segment): New function. (Output_section::is_unique_segment_): New member. (Output_section::extra_segment_flags): New function. (Output_section::set_extra_segment_flags): New function. (Output_section::extra_segment_flags_): New member. (Output_section::segment_alignment): New function. (Output_section::set_segment_alignment): New function. (Output_section::segment_alignment_): New member. (Output_segment::Output_segment): Initialize is_unique_segment_. (Output_segment::is_unique_segment): New function. (Output_segment::set_is_unique_segment): New function. (Output_segment::is_unique_segment_): New member. * plugin.cc (allow_unique_segment_for_sections): New function. (unique_segment_for_sections): New function. (Plugin::load): Add new functions to transfer vector. * Makefile.am (plugin_final_layout.readelf.stdout): Add readelf output. * Makefile.in: Regenerate. * testsuite/plugin_final_layout.sh: Check if unique segment functionality works. * testsuite/plugin_section_order.c (onload): Check if new interfaces are available. (allow_unique_segment_for_sections): New global. (unique_segment_for_sections): New global. (claim_file_hook): Call allow_unique_segment_for_sections. (all_symbols_read_hook): Call unique_segment_for_sections. 2012-08-24 Sriraman Tallam <tmsriram@google.com> * plugin-api.h (ld_plugin_allow_unique_segment_for_sections): New interface. (ld_plugin_unique_segment_for_sections): New interface. (LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val. (LDPT_UNIQUE_SEGMENT_FOR_SECTIONS): New enum val. (tv_allow_unique_segment_for_sections): New member. (tv_unique_segment_for_sections): New member.
Diffstat (limited to 'gold')
-rw-r--r--gold/ChangeLog56
-rw-r--r--gold/gold.cc10
-rw-r--r--gold/layout.cc176
-rw-r--r--gold/layout.h46
-rw-r--r--gold/object.cc110
-rw-r--r--gold/output.cc6
-rw-r--r--gold/output.h42
-rw-r--r--gold/plugin.cc78
-rw-r--r--gold/testsuite/Makefile.am4
-rw-r--r--gold/testsuite/Makefile.in5
-rwxr-xr-xgold/testsuite/plugin_final_layout.sh30
-rw-r--r--gold/testsuite/plugin_section_order.c35
12 files changed, 484 insertions, 114 deletions
diff --git a/gold/ChangeLog b/gold/ChangeLog
index 2f5fcb1..7ce8b69 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,59 @@
+2012-08-24 Sriraman Tallam <tmsriram@google.com>
+
+ * gold.cc (queue_middle_tasks): Call layout again when unique
+ segments for sections is desired.
+ * layout.cc (Layout::Layout): Initialize new members.
+ (Layout::get_output_section_flags): New function.
+ (Layout::choose_output_section): Call get_output_section_flags.
+ (Layout::layout): Make output section for mapping to a unique segment.
+ (Layout::insert_section_segment_map): New function.
+ (Layout::attach_allocated_section_to_segment): Make unique segment for
+ output sections marked so.
+ (Layout::segment_precedes): Check for unique segments when sorting.
+ * layout.h (Layout::Unique_segment_info): New struct.
+ (Layout::Section_segment_map): New typedef.
+ (Layout::insert_section_segment_map): New function.
+ (Layout::get_output_section_flags): New function.
+ (Layout::is_unique_segment_for_sections_specified): New function.
+ (Layout::set_unique_segment_for_sections_specified): New function.
+ (Layout::unique_segment_for_sections_specified_): New member.
+ (Layout::section_segment_map_): New member.
+ * object.cc (Sized_relobj_file<size, big_endian>::do_layout):
+ Rename is_gc_pass_one to is_pass_one.
+ Rename is_gc_pass_two to is_pass_two.
+ Rename is_gc_or_icf to is_two_pass.
+ Check for which pass based on whether symbols data is present.
+ Make it two pass when unique segments for sections is desired.
+ * output.cc (Output_section::Output_section): Initialize new
+ members.
+ * output.h (Output_section::is_unique_segment): New function.
+ (Output_section::set_is_unique_segment): New function.
+ (Output_section::is_unique_segment_): New member.
+ (Output_section::extra_segment_flags): New function.
+ (Output_section::set_extra_segment_flags): New function.
+ (Output_section::extra_segment_flags_): New member.
+ (Output_section::segment_alignment): New function.
+ (Output_section::set_segment_alignment): New function.
+ (Output_section::segment_alignment_): New member.
+ (Output_segment::Output_segment): Initialize is_unique_segment_.
+ (Output_segment::is_unique_segment): New function.
+ (Output_segment::set_is_unique_segment): New function.
+ (Output_segment::is_unique_segment_): New member.
+ * plugin.cc (allow_unique_segment_for_sections): New function.
+ (unique_segment_for_sections): New function.
+ (Plugin::load): Add new functions to transfer vector.
+ * Makefile.am (plugin_final_layout.readelf.stdout): Add readelf output.
+ * Makefile.in: Regenerate.
+ * testsuite/plugin_final_layout.sh: Check if unique segment
+ functionality works.
+ * testsuite/plugin_section_order.c (onload): Check if new interfaces
+ are available.
+ (allow_unique_segment_for_sections): New global.
+ (unique_segment_for_sections): New global.
+ (claim_file_hook): Call allow_unique_segment_for_sections.
+ (all_symbols_read_hook): Call unique_segment_for_sections.
+
+
2012-08-22 Cary Coutant <ccoutant@google.com>
* layout.cc (Layout::include_section): Don't assert on GROUP
diff --git a/gold/gold.cc b/gold/gold.cc
index dddf5ad..1b4badc 100644
--- a/gold/gold.cc
+++ b/gold/gold.cc
@@ -530,11 +530,13 @@ queue_middle_tasks(const General_options& options,
// Call Object::layout for the second time to determine the
// output_sections for all referenced input sections. When
- // --gc-sections or --icf is turned on, Object::layout is
- // called twice. It is called the first time when the
- // symbols are added.
+ // --gc-sections or --icf is turned on, or when certain input
+ // sections have to be mapped to unique segments, Object::layout
+ // is called twice. It is called the first time when symbols
+ // are added.
if (parameters->options().gc_sections()
- || parameters->options().icf_enabled())
+ || parameters->options().icf_enabled()
+ || layout->is_unique_segment_for_sections_specified())
{
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
p != input_objects->relobj_end();
diff --git a/gold/layout.cc b/gold/layout.cc
index db6b6ac..cadac87 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -408,12 +408,14 @@ Layout::Layout(int number_of_input_files, Script_options* script_options)
resized_signatures_(false),
have_stabstr_section_(false),
section_ordering_specified_(false),
+ unique_segment_for_sections_specified_(false),
incremental_inputs_(NULL),
record_output_section_data_from_script_(false),
script_output_section_data_list_(),
segment_states_(NULL),
relaxation_debug_check_(NULL),
section_order_map_(),
+ section_segment_map_(),
input_section_position_(),
input_section_glob_(),
incremental_base_(NULL),
@@ -824,6 +826,27 @@ Layout::keep_input_section(const Relobj* relobj, const char* name)
return name != NULL && keep;
}
+// Clear the input section flags that should not be copied to the
+// output section.
+
+elfcpp::Elf_Xword
+Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
+{
+ // Some flags in the input section should not be automatically
+ // copied to the output section.
+ input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
+ | elfcpp::SHF_GROUP
+ | elfcpp::SHF_MERGE
+ | elfcpp::SHF_STRINGS);
+
+ // We only clear the SHF_LINK_ORDER flag in for
+ // a non-relocatable link.
+ if (!parameters->options().relocatable())
+ input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
+
+ return input_section_flags;
+}
+
// Pick the output section to use for section NAME, in input file
// RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
// linker created section. IS_INPUT_SECTION is true if we are
@@ -842,17 +865,7 @@ Layout::choose_output_section(const Relobj* relobj, const char* name,
// sections to segments.
gold_assert(!is_input_section || !this->sections_are_attached_);
- // Some flags in the input section should not be automatically
- // copied to the output section.
- flags &= ~ (elfcpp::SHF_INFO_LINK
- | elfcpp::SHF_GROUP
- | elfcpp::SHF_MERGE
- | elfcpp::SHF_STRINGS);
-
- // We only clear the SHF_LINK_ORDER flag in for
- // a non-relocatable link.
- if (!parameters->options().relocatable())
- flags &= ~elfcpp::SHF_LINK_ORDER;
+ flags = this->get_output_section_flags(flags);
if (this->script_options_->saw_sections_clause())
{
@@ -1054,9 +1067,37 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
}
else
{
- os = this->choose_output_section(object, name, sh_type,
- shdr.get_sh_flags(), true,
- ORDER_INVALID, false);
+ // Plugins can choose to place one or more subsets of sections in
+ // unique segments and this is done by mapping these section subsets
+ // to unique output sections. Check if this section needs to be
+ // remapped to a unique output section.
+ Section_segment_map::iterator it
+ = this->section_segment_map_.find(Const_section_id(object, shndx));
+ if (it == this->section_segment_map_.end())
+ {
+ os = this->choose_output_section(object, name, sh_type,
+ shdr.get_sh_flags(), true,
+ ORDER_INVALID, false);
+ }
+ else
+ {
+ // We know the name of the output section, directly call
+ // get_output_section here by-passing choose_output_section.
+ elfcpp::Elf_Xword flags
+ = this->get_output_section_flags(shdr.get_sh_flags());
+
+ const char* os_name = it->second->name;
+ Stringpool::Key name_key;
+ os_name = this->namepool_.add(os_name, true, &name_key);
+ os = this->get_output_section(os_name, name_key, sh_type, flags,
+ ORDER_INVALID, false);
+ if (!os->is_unique_segment())
+ {
+ os->set_is_unique_segment();
+ os->set_extra_segment_flags(it->second->flags);
+ os->set_segment_alignment(it->second->align);
+ }
+ }
if (os == NULL)
return NULL;
}
@@ -1116,6 +1157,15 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
return os;
}
+// Maps section SECN to SEGMENT s.
+void
+Layout::insert_section_segment_map(Const_section_id secn,
+ Unique_segment_info *s)
+{
+ gold_assert(this->unique_segment_for_sections_specified_);
+ this->section_segment_map_[secn] = s;
+}
+
// Handle a relocation section when doing a relocatable link.
template<int size, bool big_endian>
@@ -1718,6 +1768,10 @@ Layout::attach_allocated_section_to_segment(const Target* target,
elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
+ // If this output section's segment has extra flags that need to be set,
+ // coming from a linker plugin, do that.
+ seg_flags |= os->extra_segment_flags();
+
// Check for --section-start.
uint64_t addr;
bool is_address_set = parameters->options().section_start(os->name(), &addr);
@@ -1730,45 +1784,51 @@ Layout::attach_allocated_section_to_segment(const Target* target,
// have to use a linker script.
Segment_list::const_iterator p;
- for (p = this->segment_list_.begin();
- p != this->segment_list_.end();
- ++p)
+ if (!os->is_unique_segment())
{
- if ((*p)->type() != elfcpp::PT_LOAD)
- continue;
- if (!parameters->options().omagic()
- && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
- continue;
- if ((target->isolate_execinstr() || parameters->options().rosegment())
- && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
- continue;
- // If -Tbss was specified, we need to separate the data and BSS
- // segments.
- if (parameters->options().user_set_Tbss())
- {
- if ((os->type() == elfcpp::SHT_NOBITS)
- == (*p)->has_any_data_sections())
- continue;
- }
- if (os->is_large_data_section() && !(*p)->is_large_data_segment())
- continue;
-
- if (is_address_set)
+ for (p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
{
- if ((*p)->are_addresses_set())
- continue;
-
- (*p)->add_initial_output_data(os);
- (*p)->update_flags_for_output_section(seg_flags);
- (*p)->set_addresses(addr, addr);
- break;
- }
-
- (*p)->add_output_section_to_load(this, os, seg_flags);
- break;
- }
-
- if (p == this->segment_list_.end())
+ if ((*p)->type() != elfcpp::PT_LOAD)
+ continue;
+ if ((*p)->is_unique_segment())
+ continue;
+ if (!parameters->options().omagic()
+ && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
+ continue;
+ if ((target->isolate_execinstr() || parameters->options().rosegment())
+ && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
+ continue;
+ // If -Tbss was specified, we need to separate the data and BSS
+ // segments.
+ if (parameters->options().user_set_Tbss())
+ {
+ if ((os->type() == elfcpp::SHT_NOBITS)
+ == (*p)->has_any_data_sections())
+ continue;
+ }
+ if (os->is_large_data_section() && !(*p)->is_large_data_segment())
+ continue;
+
+ if (is_address_set)
+ {
+ if ((*p)->are_addresses_set())
+ continue;
+
+ (*p)->add_initial_output_data(os);
+ (*p)->update_flags_for_output_section(seg_flags);
+ (*p)->set_addresses(addr, addr);
+ break;
+ }
+
+ (*p)->add_output_section_to_load(this, os, seg_flags);
+ break;
+ }
+ }
+
+ if (p == this->segment_list_.end()
+ || os->is_unique_segment())
{
Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
seg_flags);
@@ -1777,6 +1837,14 @@ Layout::attach_allocated_section_to_segment(const Target* target,
oseg->add_output_section_to_load(this, os, seg_flags);
if (is_address_set)
oseg->set_addresses(addr, addr);
+ // Check if segment should be marked unique. For segments marked
+ // unique by linker plugins, set the new alignment if specified.
+ if (os->is_unique_segment())
+ {
+ oseg->set_is_unique_segment();
+ if (os->segment_alignment() != 0)
+ oseg->set_minimum_p_align(os->segment_alignment());
+ }
}
// If we see a loadable SHT_NOTE section, we create a PT_NOTE
@@ -3121,9 +3189,11 @@ Layout::segment_precedes(const Output_segment* seg1,
// We shouldn't get here--we shouldn't create segments which we
// can't distinguish. Unless of course we are using a weird linker
- // script or overlapping --section-start options.
+ // script or overlapping --section-start options. We could also get
+ // here if plugins want unique segments for subsets of sections.
gold_assert(this->script_options_->saw_phdrs_clause()
- || parameters->options().any_section_start());
+ || parameters->options().any_section_start()
+ || this->is_unique_segment_for_sections_specified());
return false;
}
diff --git a/gold/layout.h b/gold/layout.h
index fe5c696..94745a6 100644
--- a/gold/layout.h
+++ b/gold/layout.h
@@ -528,6 +528,31 @@ class Layout
get_section_order_map()
{ return &this->section_order_map_; }
+ // Struct to store segment info when mapping some input sections to
+ // unique segments using linker plugins. Mapping an input section to
+ // a unique segment is done by first placing such input sections in
+ // unique output sections and then mapping the output section to a
+ // unique segment. NAME is the name of the output section. FLAGS
+ // and ALIGN are the extra flags and alignment of the segment.
+ struct Unique_segment_info
+ {
+ // Identifier for the segment. ELF segments dont have names. This
+ // is used as the name of the output section mapped to the segment.
+ const char* name;
+ // Additional segment flags.
+ uint64_t flags;
+ // Segment alignment.
+ uint64_t align;
+ };
+
+ // Mapping from input section to segment.
+ typedef std::map<Const_section_id, Unique_segment_info*>
+ Section_segment_map;
+
+ // Maps section SECN to SEGMENT s.
+ void
+ insert_section_segment_map(Const_section_id secn, Unique_segment_info *s);
+
bool
is_section_ordering_specified()
{ return this->section_ordering_specified_; }
@@ -536,6 +561,14 @@ class Layout
set_section_ordering_specified()
{ this->section_ordering_specified_ = true; }
+ bool
+ is_unique_segment_for_sections_specified() const
+ { return this->unique_segment_for_sections_specified_; }
+
+ void
+ set_unique_segment_for_sections_specified()
+ { this->unique_segment_for_sections_specified_ = true; }
+
// For incremental updates, allocate a block of memory from the
// free list. Find a block starting at or after MINOFF.
off_t
@@ -1070,6 +1103,11 @@ class Layout
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
Output_section_order order, bool is_relro);
+ // Clear the input section flags that should not be copied to the
+ // output section.
+ elfcpp::Elf_Xword
+ get_output_section_flags (elfcpp::Elf_Xword input_section_flags);
+
// Choose the output section for NAME in RELOBJ.
Output_section*
choose_output_section(const Relobj* relobj, const char* name,
@@ -1336,6 +1374,9 @@ class Layout
// True if the input sections in the output sections should be sorted
// as specified in a section ordering file.
bool section_ordering_specified_;
+ // True if some input sections need to be mapped to a unique segment,
+ // after being mapped to a unique Output_section.
+ bool unique_segment_for_sections_specified_;
// In incremental build, holds information check the inputs and build the
// .gnu_incremental_inputs section.
Incremental_inputs* incremental_inputs_;
@@ -1350,6 +1391,11 @@ class Layout
// Plugins specify section_ordering using this map. This is set in
// update_section_order in plugin.cc
std::map<Section_id, unsigned int> section_order_map_;
+ // This maps an input section to a unique segment. This is done by first
+ // placing such input sections in unique output sections and then mapping
+ // the output section to a unique segment. Unique_segment_info stores
+ // any additional flags and alignment of the new segment.
+ Section_segment_map section_segment_map_;
// Hash a pattern to its position in the section ordering file.
Unordered_map<std::string, unsigned int> input_section_position_;
// Vector of glob only patterns in the section_ordering file.
diff --git a/gold/object.cc b/gold/object.cc
index 417ccfc..6c0c187 100644
--- a/gold/object.cc
+++ b/gold/object.cc
@@ -1221,15 +1221,19 @@ Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
// whether they should be included in the link. If they should, we
// pass them to the Layout object, which will return an output section
// and an offset.
-// During garbage collection (--gc-sections) and identical code folding
-// (--icf), this function is called twice. When it is called the first
-// time, it is for setting up some sections as roots to a work-list for
-// --gc-sections and to do comdat processing. Actual layout happens the
-// second time around after all the relevant sections have been determined.
-// The first time, is_worklist_ready or is_icf_ready is false. It is then
-// set to true after the garbage collection worklist or identical code
-// folding is processed and the relevant sections to be kept are
-// determined. Then, this function is called again to layout the sections.
+// This function is called twice sometimes, two passes, when mapping
+// of input sections to output sections must be delayed.
+// This is true for the following :
+// * Garbage collection (--gc-sections): Some input sections will be
+// discarded and hence the assignment must wait until the second pass.
+// In the first pass, it is for setting up some sections as roots to
+// a work-list for --gc-sections and to do comdat processing.
+// * Identical Code Folding (--icf=<safe,all>): Some input sections
+// will be folded and hence the assignment must wait.
+// * Using plugins to map some sections to unique segments: Mapping
+// some sections to unique segments requires mapping them to unique
+// output sections too. This can be done via plugins now and this
+// information is not available in the first pass.
template<int size, bool big_endian>
void
@@ -1238,26 +1242,44 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
Read_symbols_data* sd)
{
const unsigned int shnum = this->shnum();
- bool is_gc_pass_one = ((parameters->options().gc_sections()
- && !symtab->gc()->is_worklist_ready())
- || (parameters->options().icf_enabled()
- && !symtab->icf()->is_icf_ready()));
- bool is_gc_pass_two = ((parameters->options().gc_sections()
- && symtab->gc()->is_worklist_ready())
- || (parameters->options().icf_enabled()
- && symtab->icf()->is_icf_ready()));
+ /* Should this function be called twice? */
+ bool is_two_pass = (parameters->options().gc_sections()
+ || parameters->options().icf_enabled()
+ || layout->is_unique_segment_for_sections_specified());
- bool is_gc_or_icf = (parameters->options().gc_sections()
- || parameters->options().icf_enabled());
+ /* Only one of is_pass_one and is_pass_two is true. Both are false when
+ a two-pass approach is not needed. */
+ bool is_pass_one = false;
+ bool is_pass_two = false;
- // Both is_gc_pass_one and is_gc_pass_two should not be true.
- gold_assert(!(is_gc_pass_one && is_gc_pass_two));
+ Symbols_data* gc_sd = NULL;
+ /* Check if do_layout needs to be two-pass. If so, find out which pass
+ should happen. In the first pass, the data in sd is saved to be used
+ later in the second pass. */
+ if (is_two_pass)
+ {
+ gc_sd = this->get_symbols_data();
+ if (gc_sd == NULL)
+ {
+ gold_assert(sd != NULL);
+ is_pass_one = true;
+ }
+ else
+ {
+ if (parameters->options().gc_sections())
+ gold_assert(symtab->gc()->is_worklist_ready());
+ if (parameters->options().icf_enabled())
+ gold_assert(symtab->icf()->is_icf_ready());
+ is_pass_two = true;
+ }
+ }
+
if (shnum == 0)
return;
- Symbols_data* gc_sd = NULL;
- if (is_gc_pass_one)
+
+ if (is_pass_one)
{
// During garbage collection save the symbols data to use it when
// re-entering this function.
@@ -1265,10 +1287,6 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
this->set_symbols_data(gc_sd);
}
- else if (is_gc_pass_two)
- {
- gc_sd = this->get_symbols_data();
- }
const unsigned char* section_headers_data = NULL;
section_size_type section_names_size;
@@ -1277,7 +1295,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
const unsigned char* symbol_names_data = NULL;
section_size_type symbol_names_size;
- if (is_gc_or_icf)
+ if (is_two_pass)
{
section_headers_data = gc_sd->section_headers_data;
section_names_size = gc_sd->section_names_size;
@@ -1303,9 +1321,9 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
const unsigned char* pshdrs;
// Get the section names.
- const unsigned char* pnamesu = (is_gc_or_icf)
- ? gc_sd->section_names_data
- : sd->section_names->data();
+ const unsigned char* pnamesu = (is_two_pass
+ ? gc_sd->section_names_data
+ : sd->section_names->data());
const char* pnames = reinterpret_cast<const char*>(pnamesu);
@@ -1355,7 +1373,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
Output_sections& out_sections(this->output_sections());
std::vector<Address>& out_section_offsets(this->section_offsets());
- if (!is_gc_pass_two)
+ if (!is_pass_two)
{
out_sections.resize(shnum);
out_section_offsets.resize(shnum);
@@ -1365,7 +1383,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
// do here.
if (this->input_file()->just_symbols())
{
- if (!is_gc_pass_two)
+ if (!is_pass_two)
{
delete sd->section_headers;
sd->section_headers = NULL;
@@ -1417,7 +1435,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
const char* name = pnames + shdr.get_sh_name();
- if (!is_gc_pass_two)
+ if (!is_pass_two)
{
if (this->handle_gnu_warning_section(name, i, symtab))
{
@@ -1491,7 +1509,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
}
}
- if (is_gc_pass_one && parameters->options().gc_sections())
+ if (is_pass_one && parameters->options().gc_sections())
{
if (this->is_section_name_included(name)
|| layout->keep_input_section (this, name)
@@ -1537,7 +1555,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
&& strcmp(name, ".eh_frame") == 0
&& this->check_eh_frame_flags(&shdr))
{
- if (is_gc_pass_one)
+ if (is_pass_one)
{
out_sections[i] = reinterpret_cast<Output_section*>(1);
out_section_offsets[i] = invalid_address;
@@ -1552,7 +1570,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
continue;
}
- if (is_gc_pass_two && parameters->options().gc_sections())
+ if (is_pass_two && parameters->options().gc_sections())
{
// This is executed during the second pass of garbage
// collection. do_layout has been called before and some
@@ -1577,7 +1595,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
}
}
- if (is_gc_pass_two && parameters->options().icf_enabled())
+ if (is_pass_two && parameters->options().icf_enabled())
{
if (out_sections[i] == NULL)
{
@@ -1611,7 +1629,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
// should_defer_layout should be false.
if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
{
- gold_assert(!is_gc_pass_two);
+ gold_assert(!is_pass_two);
this->deferred_layout_.push_back(Deferred_layout(i, name,
pshdrs,
reloc_shndx[i],
@@ -1626,11 +1644,11 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
// During gc_pass_two if a section that was previously deferred is
// found, do not layout the section as layout_deferred_sections will
// do it later from gold.cc.
- if (is_gc_pass_two
+ if (is_pass_two
&& (out_sections[i] == reinterpret_cast<Output_section*>(2)))
continue;
- if (is_gc_pass_one)
+ if (is_pass_one)
{
// This is during garbage collection. The out_sections are
// assigned in the second call to this function.
@@ -1661,7 +1679,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
}
}
- if (!is_gc_pass_two)
+ if (!is_pass_two)
layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
// When doing a relocatable link handle the reloc sections at the
@@ -1670,7 +1688,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
if (emit_relocs)
this->size_relocatable_relocs();
- gold_assert(!(is_gc_or_icf) || reloc_sections.empty());
+ gold_assert(!is_two_pass || reloc_sections.empty());
for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
p != reloc_sections.end();
@@ -1717,7 +1735,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
}
// Handle the .eh_frame sections at the end.
- gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
+ gold_assert(!is_pass_one || eh_frame_sections.empty());
for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
p != eh_frame_sections.end();
++p)
@@ -1740,7 +1758,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
// When building a .gdb_index section, scan the .debug_info and
// .debug_types sections.
- gold_assert(!is_gc_pass_one
+ gold_assert(!is_pass_one
|| (debug_info_sections.empty() && debug_types_sections.empty()));
for (std::vector<unsigned int>::const_iterator p
= debug_info_sections.begin();
@@ -1761,7 +1779,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
i, reloc_shndx[i], reloc_type[i]);
}
- if (is_gc_pass_two)
+ if (is_pass_two)
{
delete[] gc_sd->section_headers_data;
delete[] gc_sd->section_names_data;
diff --git a/gold/output.cc b/gold/output.cc
index 9556abf..2539aac 100644
--- a/gold/output.cc
+++ b/gold/output.cc
@@ -2257,7 +2257,10 @@ Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
always_keeps_input_sections_(false),
has_fixed_layout_(false),
is_patch_space_allowed_(false),
+ is_unique_segment_(false),
tls_offset_(0),
+ extra_segment_flags_(0),
+ segment_alignment_(0),
checkpoint_(NULL),
lookup_maps_(new Output_section_lookup_maps),
free_list_(),
@@ -3991,7 +3994,8 @@ Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
flags_(flags),
is_max_align_known_(false),
are_addresses_set_(false),
- is_large_data_segment_(false)
+ is_large_data_segment_(false),
+ is_unique_segment_(false)
{
// The ELF ABI specifies that a PT_TLS segment always has PF_R as
// the flags.
diff --git a/gold/output.h b/gold/output.h
index 9b0f87f..25a6b89 100644
--- a/gold/output.h
+++ b/gold/output.h
@@ -3265,6 +3265,28 @@ class Output_section : public Output_data
requires_postprocessing() const
{ return this->requires_postprocessing_; }
+ bool
+ is_unique_segment() const
+ { return this->is_unique_segment_; }
+
+ void
+ set_is_unique_segment()
+ { this->is_unique_segment_ = true; }
+
+ uint64_t extra_segment_flags() const
+ { return this->extra_segment_flags_; }
+
+ void
+ set_extra_segment_flags(uint64_t flags)
+ { this->extra_segment_flags_ = flags; }
+
+ uint64_t segment_alignment() const
+ { return this->segment_alignment_; }
+
+ void
+ set_segment_alignment(uint64_t align)
+ { this->segment_alignment_ = align; }
+
// If a section requires postprocessing, return the buffer to use.
unsigned char*
postprocessing_buffer() const
@@ -4216,9 +4238,17 @@ class Output_section : public Output_data
bool has_fixed_layout_ : 1;
// True if we can add patch space to this section.
bool is_patch_space_allowed_ : 1;
+ // True if this output section goes into a unique segment.
+ bool is_unique_segment_ : 1;
// For SHT_TLS sections, the offset of this section relative to the base
// of the TLS segment.
uint64_t tls_offset_;
+ // Additional segment flags, specified via linker plugin, when mapping some
+ // input sections to unique segments.
+ uint64_t extra_segment_flags_;
+ // Segment alignment specified via linker plugin, when mapping some
+ // input sections to unique segments.
+ uint64_t segment_alignment_;
// Saved checkpoint.
Checkpoint_output_section* checkpoint_;
// Fast lookup maps for merged and relaxed input sections.
@@ -4294,6 +4324,16 @@ class Output_segment
set_is_large_data_segment()
{ this->is_large_data_segment_ = true; }
+ bool
+ is_unique_segment() const
+ { return this->is_unique_segment_; }
+
+ // Mark segment as unique, happens when linker plugins request that
+ // certain input sections be mapped to unique segments.
+ void
+ set_is_unique_segment()
+ { this->is_unique_segment_ = true; }
+
// Return the maximum alignment of the Output_data.
uint64_t
maximum_alignment();
@@ -4504,6 +4544,8 @@ class Output_segment
bool are_addresses_set_ : 1;
// Whether this segment holds large data sections.
bool is_large_data_segment_ : 1;
+ // Whether this was marked as a unique segment via a linker plugin.
+ bool is_unique_segment_ : 1;
};
// This class represents the output file.
diff --git a/gold/plugin.cc b/gold/plugin.cc
index 5aadc55..c39e11ec 100644
--- a/gold/plugin.cc
+++ b/gold/plugin.cc
@@ -115,6 +115,15 @@ update_section_order(const struct ld_plugin_section *section_list,
static enum ld_plugin_status
allow_section_ordering();
+static enum ld_plugin_status
+allow_unique_segment_for_sections();
+
+static enum ld_plugin_status
+unique_segment_for_sections(const char* segment_name,
+ uint64_t flags,
+ uint64_t align,
+ const struct ld_plugin_section *section_list,
+ unsigned int num_sections);
};
#endif // ENABLE_PLUGINS
@@ -159,7 +168,7 @@ Plugin::load()
sscanf(ver, "%d.%d", &major, &minor);
// Allocate and populate a transfer vector.
- const int tv_fixed_size = 24;
+ const int tv_fixed_size = 26;
int tv_size = this->args_.size() + tv_fixed_size;
ld_plugin_tv* tv = new ld_plugin_tv[tv_size];
@@ -273,6 +282,15 @@ Plugin::load()
tv[i].tv_u.tv_allow_section_ordering = allow_section_ordering;
++i;
+ tv[i].tv_tag = LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS;
+ tv[i].tv_u.tv_allow_unique_segment_for_sections
+ = allow_unique_segment_for_sections;
+
+ ++i;
+ tv[i].tv_tag = LDPT_UNIQUE_SEGMENT_FOR_SECTIONS;
+ tv[i].tv_u.tv_unique_segment_for_sections = unique_segment_for_sections;
+
+ ++i;
tv[i].tv_tag = LDPT_NULL;
tv[i].tv_u.tv_val = 0;
@@ -1685,6 +1703,64 @@ allow_section_ordering()
return LDPS_OK;
}
+// Let the linker know that a subset of sections could be mapped
+// to a unique segment.
+
+static enum ld_plugin_status
+allow_unique_segment_for_sections()
+{
+ gold_assert(parameters->options().has_plugins());
+ Layout* layout = parameters->options().plugins()->layout();
+ layout->set_unique_segment_for_sections_specified();
+ return LDPS_OK;
+}
+
+// This function should map the list of sections specified in the
+// SECTION_LIST to a unique segment. ELF segments do not have names
+// and the NAME is used to identify Output Section which should contain
+// the list of sections. This Output Section will then be mapped to
+// a unique segment. FLAGS is used to specify if any additional segment
+// flags need to be set. For instance, a specific segment flag can be
+// set to identify this segment. Unsetting segment flags is not possible.
+// ALIGN specifies the alignment of the segment.
+
+static enum ld_plugin_status
+unique_segment_for_sections(const char* segment_name,
+ uint64_t flags,
+ uint64_t align,
+ const struct ld_plugin_section* section_list,
+ unsigned int num_sections)
+{
+ gold_assert(parameters->options().has_plugins());
+
+ if (num_sections == 0)
+ return LDPS_OK;
+
+ if (section_list == NULL)
+ return LDPS_ERR;
+
+ Layout* layout = parameters->options().plugins()->layout();
+ gold_assert (layout != NULL);
+
+ Layout::Unique_segment_info* s = new Layout::Unique_segment_info;
+ s->name = segment_name;
+ s->flags = flags;
+ s->align = align;
+
+ for (unsigned int i = 0; i < num_sections; ++i)
+ {
+ Object* obj = parameters->options().plugins()->get_elf_object(
+ section_list[i].handle);
+ if (obj == NULL)
+ return LDPS_BAD_HANDLE;
+ unsigned int shndx = section_list[i].shndx;
+ Const_section_id secn_id(obj, shndx);
+ layout->insert_section_segment_map(secn_id, s);
+ }
+
+ return LDPS_OK;
+}
+
#endif // ENABLE_PLUGINS
// Allocate a Pluginobj object of the appropriate size and endianness.
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 0e98e6a..146c7e0 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -1529,13 +1529,15 @@ unused.c:
@cp /dev/null $@
check_SCRIPTS += plugin_final_layout.sh
-check_DATA += plugin_final_layout.stdout
+check_DATA += plugin_final_layout.stdout plugin_final_layout_readelf.stdout
plugin_final_layout.o: plugin_final_layout.cc
$(CXXCOMPILE) -O0 -c -ffunction-sections -fdata-sections -g -o $@ $<
plugin_final_layout: plugin_final_layout.o plugin_section_order.so gcctestdir/ld
$(CXXLINK) -Bgcctestdir/ -Wl,--plugin,"./plugin_section_order.so" plugin_final_layout.o
plugin_final_layout.stdout: plugin_final_layout
$(TEST_NM) -n plugin_final_layout > plugin_final_layout.stdout
+plugin_final_layout_readelf.stdout: plugin_final_layout
+ $(TEST_READELF) -Wl plugin_final_layout > plugin_final_layout_readelf.stdout
plugin_section_order.so: plugin_section_order.o
$(LINK) -Bgcctestdir/ -shared plugin_section_order.o
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index a3a4506..b937ff0 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -329,7 +329,8 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_test_7.err \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_test_7.syms \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_test_9.err \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_final_layout.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_final_layout.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_final_layout.readelf.stdout
# Make a copy of two_file_test_1.o, which does not define the symbol _Z4t16av.
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_36 = \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_test_1.err \
@@ -4875,6 +4876,8 @@ uninstall-am:
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(CXXLINK) -Bgcctestdir/ -Wl,--plugin,"./plugin_section_order.so" plugin_final_layout.o
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_final_layout.stdout: plugin_final_layout
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(TEST_NM) -n plugin_final_layout > plugin_final_layout.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_final_layout.readelf.stdout: plugin_final_layout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(TEST_READELF) -Wl plugin_final_layout > plugin_final_layout_readelf.stdout
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_section_order.so: plugin_section_order.o
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(LINK) -Bgcctestdir/ -shared plugin_section_order.o
diff --git a/gold/testsuite/plugin_final_layout.sh b/gold/testsuite/plugin_final_layout.sh
index 600f8e2..75a40d3 100755
--- a/gold/testsuite/plugin_final_layout.sh
+++ b/gold/testsuite/plugin_final_layout.sh
@@ -56,5 +56,35 @@ END {
}" $1
}
+# With readelf -l, an ELF Section to Segment mapping is printed as :
+##############################################
+# Section to Segment mapping:
+# Segment Sections...
+# ...
+# 0x .text.plugin_created_unique
+# ...
+##############################################
+# Check of .text.plugin_created_unique is the only section in the segment.
+check_unique_segment()
+{
+ awk "
+BEGIN { saw_section = 0; saw_unique = 0; }
+/$2/ { saw_section = 1; }
+/[ ]*0[0-9][ ]*$2[ ]*\$/ { saw_unique = 1; }
+END {
+ if (!saw_section)
+ {
+ printf \"Section $2 not seen in output\\n\";
+ exit 1;
+ }
+ else if (!saw_unique)
+ {
+ printf \"Unique segment not seen for: $2\\n\";
+ exit 1;
+ }
+ }" $1
+}
+
check plugin_final_layout.stdout "_Z3foov" "_Z3barv"
check plugin_final_layout.stdout "_Z3barv" "_Z3bazv"
+check_unique_segment plugin_final_layout_readelf.stdout ".text.plugin_created_unique"
diff --git a/gold/testsuite/plugin_section_order.c b/gold/testsuite/plugin_section_order.c
index 0e2079b..fdc6fe4 100644
--- a/gold/testsuite/plugin_section_order.c
+++ b/gold/testsuite/plugin_section_order.c
@@ -36,6 +36,9 @@ static ld_plugin_get_input_section_name get_input_section_name = NULL;
static ld_plugin_get_input_section_contents get_input_section_contents = NULL;
static ld_plugin_update_section_order update_section_order = NULL;
static ld_plugin_allow_section_ordering allow_section_ordering = NULL;
+static ld_plugin_allow_unique_segment_for_sections
+ allow_unique_segment_for_sections = NULL;
+static ld_plugin_unique_segment_for_sections unique_segment_for_sections = NULL;
enum ld_plugin_status onload(struct ld_plugin_tv *tv);
enum ld_plugin_status claim_file_hook(const struct ld_plugin_input_file *file,
@@ -52,11 +55,13 @@ onload(struct ld_plugin_tv *tv)
switch (entry->tv_tag)
{
case LDPT_REGISTER_CLAIM_FILE_HOOK:
- assert((*entry->tv_u.tv_register_claim_file) (claim_file_hook) == LDPS_OK);
+ assert((*entry->tv_u.tv_register_claim_file) (claim_file_hook)
+ == LDPS_OK);
break;
case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
- assert((*entry->tv_u.tv_register_all_symbols_read) (all_symbols_read_hook)
- == LDPS_OK);
+ assert((*entry->tv_u.tv_register_all_symbols_read)
+ (all_symbols_read_hook)
+ == LDPS_OK);
break;
case LDPT_GET_INPUT_SECTION_COUNT:
get_input_section_count = *entry->tv_u.tv_get_input_section_count;
@@ -68,7 +73,8 @@ onload(struct ld_plugin_tv *tv)
get_input_section_name = *entry->tv_u.tv_get_input_section_name;
break;
case LDPT_GET_INPUT_SECTION_CONTENTS:
- get_input_section_contents = *entry->tv_u.tv_get_input_section_contents;
+ get_input_section_contents
+ = *entry->tv_u.tv_get_input_section_contents;
break;
case LDPT_UPDATE_SECTION_ORDER:
update_section_order = *entry->tv_u.tv_update_section_order;
@@ -76,6 +82,13 @@ onload(struct ld_plugin_tv *tv)
case LDPT_ALLOW_SECTION_ORDERING:
allow_section_ordering = *entry->tv_u.tv_allow_section_ordering;
break;
+ case LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS:
+ allow_unique_segment_for_sections
+ = *entry->tv_u.tv_allow_unique_segment_for_sections;
+ case LDPT_UNIQUE_SEGMENT_FOR_SECTIONS:
+ unique_segment_for_sections
+ = *entry->tv_u.tv_unique_segment_for_sections;
+ break;
default:
break;
}
@@ -86,7 +99,9 @@ onload(struct ld_plugin_tv *tv)
|| get_input_section_name == NULL
|| get_input_section_contents == NULL
|| update_section_order == NULL
- || allow_section_ordering == NULL)
+ || allow_section_ordering == NULL
+ || allow_unique_segment_for_sections == NULL
+ || unique_segment_for_sections == NULL)
{
fprintf(stderr, "Some interfaces are missing\n");
return LDPS_ERR;
@@ -117,6 +132,9 @@ claim_file_hook(const struct ld_plugin_input_file *file, int *claimed)
{
/* Inform the linker to prepare for section reordering. */
(*allow_section_ordering)();
+ /* Inform the linker to prepare to map some sections to unique
+ segments. */
+ (*allow_unique_segment_for_sections)();
is_ordering_specified = 1;
}
@@ -160,8 +178,11 @@ enum ld_plugin_status
all_symbols_read_hook(void)
{
if (num_entries == 3)
- update_section_order(section_list, num_entries);
+ {
+ update_section_order(section_list, num_entries);
+ unique_segment_for_sections (".text.plugin_created_unique", 0, 0x1000,
+ section_list, num_entries);
+ }
return LDPS_OK;
}
-