PR ld/10515
[binutils-gdb.git] / gold / reloc.cc
index b44dd721b1d1b4f3a3d2a15606e498b53121f842..0842a73ca83a78d7725a1fbf0ea9343bae6777dc 100644 (file)
@@ -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 or identical comdat folding is desired, we  
+  // process the relocs first before scanning them.  Scanning of relocs is
+  // done only after garbage or identical sections is identified.
+  if (parameters->options().gc_sections() || parameters->options().icf())
+    {
+      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
@@ -193,7 +247,8 @@ Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
 
   rd->relocs.reserve(shnum / 2);
 
-  std::vector<Map_to_output>& map_sections(this->map_to_output());
+  const Output_sections& out_sections(this->output_sections());
+  const std::vector<Address>& out_offsets(this->section_offsets_);
 
   const unsigned char *pshdrs = this->get_view(this->elf_file_.shoff(),
                                               shnum * This::shdr_size,
@@ -216,7 +271,7 @@ Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
          continue;
        }
 
-      Output_section* os = map_sections[shndx].output_section;
+      Output_section* os = out_sections[shndx];
       if (os == NULL)
        continue;
 
@@ -224,7 +279,9 @@ Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
       // PLT sections.  Relocations for sections which are not
       // allocated (typically debugging sections) should not add new
       // GOT and PLT entries.  So we skip them unless this is a
-      // relocatable link or we need to emit relocations.
+      // relocatable link or we need to emit relocations.  FIXME: What
+      // should we do if a linker script maps a section with SHF_ALLOC
+      // clear to a section with SHF_ALLOC set?
       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
                                   != 0);
@@ -273,7 +330,7 @@ Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
       sr.sh_type = sh_type;
       sr.reloc_count = reloc_count;
       sr.output_section = os;
-      sr.needs_special_offset_handling = map_sections[shndx].offset == -1;
+      sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
       sr.is_data_section_allocated = is_section_allocated;
     }
 
@@ -295,6 +352,47 @@ 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.
 
@@ -317,6 +415,14 @@ 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() || parameters->options().icf())
+        {
+          if (p->output_section == NULL)
+            continue;
+        }
       if (!parameters->options().relocatable())
        {
          // As noted above, when not generating an object file, we
@@ -367,7 +473,7 @@ class Emit_relocs_strategy
  public:
   // A local non-section symbol.
   inline Relocatable_relocs::Reloc_strategy
-  local_non_section_strategy(unsigned int, Relobj*)
+  local_non_section_strategy(unsigned int, Relobj*, unsigned int)
   { return Relocatable_relocs::RELOC_COPY; }
 
   // A local section symbol.
@@ -534,7 +640,8 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
                                               Views* pviews)
 {
   unsigned int shnum = this->shnum();
-  const std::vector<Map_to_output>& map_sections(this->map_to_output());
+  const Output_sections& out_sections(this->output_sections());
+  const std::vector<Address>& out_offsets(this->section_offsets_);
 
   File_read::Read_multiple rm;
   bool is_sorted = true;
@@ -546,10 +653,10 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
 
       pvs->view = NULL;
 
-      const Output_section* os = map_sections[i].output_section;
+      const Output_section* os = out_sections[i];
       if (os == NULL)
        continue;
-      off_t output_offset = map_sections[i].offset;
+      Address output_offset = out_offsets[i];
 
       typename This::Shdr shdr(p);
 
@@ -584,8 +691,8 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
       // In the normal case, this input section is simply mapped to
       // the output section at offset OUTPUT_OFFSET.
 
-      // However, if OUTPUT_OFFSET == -1, then input data is handled
-      // specially--e.g., a .eh_frame section.  The relocation
+      // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
+      // handled specially--e.g., a .eh_frame section.  The relocation
       // routines need to check for each reloc where it should be
       // applied.  For this case, we need an input/output view for the
       // entire contents of the section in the output file.  We don't
@@ -602,21 +709,22 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
       // final data to the output file.
 
       off_t output_section_offset;
-      off_t output_section_size;
+      Address output_section_size;
       if (!os->requires_postprocessing())
        {
          output_section_offset = os->offset();
-         output_section_size = os->data_size();
+         output_section_size = convert_types<Address, off_t>(os->data_size());
        }
       else
        {
          output_section_offset = 0;
-         output_section_size = os->postprocessing_buffer_size();
+         output_section_size =
+              convert_types<Address, off_t>(os->postprocessing_buffer_size());
        }
 
       off_t view_start;
       section_size_type view_size;
-      if (output_offset != -1)
+      if (output_offset != invalid_address)
        {
          view_start = output_section_offset + output_offset;
          view_size = convert_to_section_size_type(shdr.get_sh_size());
@@ -630,17 +738,15 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
       if (view_size == 0)
        continue;
 
-      gold_assert(output_offset == -1
-                 || (output_offset >= 0
-                     && (output_offset + static_cast<off_t>(view_size)
-                          <= output_section_size)));
+      gold_assert(output_offset == invalid_address
+                 || output_offset + view_size <= output_section_size);
 
       unsigned char* view;
       if (os->requires_postprocessing())
        {
          unsigned char* buffer = os->postprocessing_buffer();
          view = buffer + view_start;
-         if (output_offset != -1)
+         if (output_offset != invalid_address)
            {
              off_t sh_offset = shdr.get_sh_offset();
              if (!rm.empty() && rm.back().file_offset > sh_offset)
@@ -651,7 +757,7 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
        }
       else
        {
-         if (output_offset == -1)
+         if (output_offset == invalid_address)
            view = of->get_input_output_view(view_start, view_size);
          else
            {
@@ -666,11 +772,11 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
 
       pvs->view = view;
       pvs->address = os->address();
-      if (output_offset != -1)
+      if (output_offset != invalid_address)
        pvs->address += output_offset;
       pvs->offset = view_start;
       pvs->view_size = view_size;
-      pvs->is_input_output_view = output_offset == -1;
+      pvs->is_input_output_view = output_offset == invalid_address;
       pvs->is_postprocessing_view = os->requires_postprocessing();
     }
 
@@ -698,7 +804,8 @@ Sized_relobj<size, big_endian>::relocate_sections(
   unsigned int shnum = this->shnum();
   Sized_target<size, big_endian>* target = this->sized_target();
 
-  const std::vector<Map_to_output>& map_sections(this->map_to_output());
+  const Output_sections& out_sections(this->output_sections());
+  const std::vector<Address>& out_offsets(this->section_offsets_);
 
   Relocate_info<size, big_endian> relinfo;
   relinfo.options = &options;
@@ -715,6 +822,10 @@ Sized_relobj<size, big_endian>::relocate_sections(
       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
        continue;
 
+      off_t sh_size = shdr.get_sh_size();
+      if (sh_size == 0)
+       continue;
+
       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
       if (index >= this->shnum())
        {
@@ -723,14 +834,14 @@ Sized_relobj<size, big_endian>::relocate_sections(
          continue;
        }
 
-      Output_section* os = map_sections[index].output_section;
+      Output_section* os = out_sections[index];
       if (os == NULL)
        {
          // This relocation section is against a section which we
          // discarded.
          continue;
        }
-      off_t output_offset = map_sections[index].offset;
+      Address output_offset = out_offsets[index];
 
       gold_assert((*pviews)[index].view != NULL);
       if (parameters->options().relocatable())
@@ -744,7 +855,6 @@ Sized_relobj<size, big_endian>::relocate_sections(
          continue;
        }
 
-      off_t sh_size = shdr.get_sh_size();
       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
                                                    sh_size, true, false);
 
@@ -770,7 +880,7 @@ Sized_relobj<size, big_endian>::relocate_sections(
          continue;
        }
 
-      gold_assert(output_offset != -1
+      gold_assert(output_offset != invalid_address
                  || this->relocs_must_follow_section_writes());
 
       relinfo.reloc_shndx = i;
@@ -782,7 +892,7 @@ Sized_relobj<size, big_endian>::relocate_sections(
                                   prelocs,
                                   reloc_count,
                                   os,
-                                  output_offset == -1,
+                                  output_offset == invalid_address,
                                   (*pviews)[index].view,
                                   (*pviews)[index].address,
                                   (*pviews)[index].view_size);
@@ -825,7 +935,7 @@ Sized_relobj<size, big_endian>::emit_relocs(
     const unsigned char* prelocs,
     size_t reloc_count,
     Output_section* output_section,
-    off_t offset_in_output_section,
+    typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
     unsigned char* view,
     typename elfcpp::Elf_types<size>::Elf_Addr address,
     section_size_type view_size,
@@ -861,7 +971,7 @@ Sized_relobj<size, big_endian>::emit_relocs_reltype(
     const unsigned char* prelocs,
     size_t reloc_count,
     Output_section* output_section,
-    off_t offset_in_output_section,
+    typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
     unsigned char* view,
     typename elfcpp::Elf_types<size>::Elf_Addr address,
     section_size_type view_size,
@@ -1075,6 +1185,42 @@ void
 Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
 #endif
 
+#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