[2.22] Fix ld.gold/arm from producing __exidx_start/__exidx_end

See http://sourceware.org/ml/binutils/2012-03/txt00005.txt
Backport of binutils (revision, file)

  1.146 gold/arm.cc
  1.97  gold/gold.cc
  1.63  gold/target.h
  1.188 gold/testsuite/Makefile.am
  1.2   gold/testsuite/arm_exidx_test.s
  1.1   gold/testsuite/arm_exidx_test.sh

Change-Id: Id7d79684fec9945540ff17a5773163214bd9d371

6 files changed, 99 insertions, 31 deletions

diff --git a/binutils-2.22/gold/arm.cc b/binutils-2.22/gold/arm.cc
index e31bb60..d41ba350 100644
--- a/binutils-2.22/gold/arm.cc
+++ b/binutils-2.22/gold/arm.cc
@@ -2574,6 +2574,9 @@ class Target_arm : public Sized_target<32, big_endian>
 	    && Target::do_section_may_have_icf_unsafe_pointers(section_name));
   }
   
+  virtual void
+  do_define_standard_symbols(Symbol_table*, Layout*);
+
  private:
   // The class which scans relocations.
   class Scan
@@ -8582,7 +8585,7 @@ void
 Target_arm<big_endian>::do_finalize_sections(
     Layout* layout,
     const Input_objects* input_objects,
-    Symbol_table* symtab)
+    Symbol_table*)
 {
   bool merged_any_attributes = false;
   // Merge processor-specific flags.
@@ -8669,18 +8672,6 @@ Target_arm<big_endian>::do_finalize_sections(
       if (exidx_section != NULL
           && exidx_section->type() == elfcpp::SHT_ARM_EXIDX)
         {
-          // Create __exidx_start and __exidx_end symbols.
-          symtab->define_in_output_data("__exidx_start", NULL,
-                                        Symbol_table::PREDEFINED,
-                                        exidx_section, 0, 0, elfcpp::STT_OBJECT,
-                                        elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
-                                        0, false, true);
-          symtab->define_in_output_data("__exidx_end", NULL,
-                                        Symbol_table::PREDEFINED,
-                                        exidx_section, 0, 0, elfcpp::STT_OBJECT,
-                                        elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
-                                        0, true, true);
-
           // For the ARM target, we need to add a PT_ARM_EXIDX segment for
           // the .ARM.exidx section.
           if (!layout->script_options()->saw_phdrs_clause())
@@ -8694,19 +8685,6 @@ Target_arm<big_endian>::do_finalize_sections(
                                                            elfcpp::PF_R);
             }
         }
-      else
-        {
-          symtab->define_as_constant("__exidx_start", NULL,
-                                     Symbol_table::PREDEFINED,
-                                     0, 0, elfcpp::STT_OBJECT,
-                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, 0,
-                                     true, false);
-          symtab->define_as_constant("__exidx_end", NULL,
-                                     Symbol_table::PREDEFINED,
-                                     0, 0, elfcpp::STT_OBJECT,
-                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, 0,
-                                     true, false);
-        }
     }
 
   // Create an .ARM.attributes section if we have merged any attributes
@@ -11994,6 +11972,61 @@ Target_arm<big_endian>::fix_exidx_coverage(
 				    merge_exidx_entries(), task);
 }
 
+template<bool big_endian>
+void
+Target_arm<big_endian>::do_define_standard_symbols(
+    Symbol_table* symtab,
+    Layout* layout)
+{
+  // Handle the .ARM.exidx section.
+  Output_section* exidx_section = layout->find_output_section(".ARM.exidx");
+
+  if (exidx_section != NULL)
+    {
+      // Create __exidx_start and __exidx_end symbols.
+      symtab->define_in_output_data("__exidx_start",
+				    NULL, // version
+				    Symbol_table::PREDEFINED,
+				    exidx_section,
+				    0, // value
+				    0, // symsize
+				    elfcpp::STT_NOTYPE,
+				    elfcpp::STB_GLOBAL,
+				    elfcpp::STV_HIDDEN,
+				    0, // nonvis
+				    false, // offset_is_from_end
+				    true); // only_if_ref
+
+      symtab->define_in_output_data("__exidx_end",
+				    NULL, // version
+				    Symbol_table::PREDEFINED,
+				    exidx_section,
+				    0, // value
+				    0, // symsize
+				    elfcpp::STT_NOTYPE,
+				    elfcpp::STB_GLOBAL,
+				    elfcpp::STV_HIDDEN,
+				    0, // nonvis
+				    true, // offset_is_from_end
+				    true); // only_if_ref
+    }
+  else
+    {
+      // Define __exidx_start and __exidx_end even when .ARM.exidx
+      // section is missing to match ld's behaviour.
+      symtab->define_as_constant("__exidx_start", NULL,
+				 Symbol_table::PREDEFINED,
+				 0, 0, elfcpp::STT_OBJECT,
+				 elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, 0,
+				 true, false);
+      symtab->define_as_constant("__exidx_end", NULL,
+				 Symbol_table::PREDEFINED,
+				 0, 0, elfcpp::STT_OBJECT,
+				 elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, 0,
+				 true, false);
+    }
+}
+
 Target_selector_arm<false> target_selector_arm;
 Target_selector_arm<true> target_selector_armbe;
 
diff --git a/binutils-2.22/gold/gold.cc b/binutils-2.22/gold/gold.cc
index 12f25b7..f2d73fe 100644
--- a/binutils-2.22/gold/gold.cc
+++ b/binutils-2.22/gold/gold.cc
@@ -674,6 +674,9 @@ queue_middle_tasks(const General_options& options,
   // Define symbols from any linker scripts.
   layout->define_script_symbols(symtab);
 
+  // TODO(csilvers): figure out a more principled way to get the target
+  Target* target = const_cast<Target*>(&parameters->target());
+
   // Attach sections to segments.
   layout->attach_sections_to_segments();
 
@@ -685,6 +688,9 @@ queue_middle_tasks(const General_options& options,
       // Define __start and __stop symbols for output sections where
       // appropriate.
       layout->define_section_symbols(symtab);
+
+      // Define target-specific symbols.
+      target->define_standard_symbols(symtab, layout);
     }
 
   // Make sure we have symbols for any required group signatures.
@@ -766,8 +772,6 @@ queue_middle_tasks(const General_options& options,
 
   // When all those tasks are complete, we can start laying out the
   // output file.
-  // TODO(csilvers): figure out a more principled way to get the target
-  Target* target = const_cast<Target*>(&parameters->target());
   workqueue->queue(new Task_function(new Layout_task_runner(options,
 							    input_objects,
 							    symtab,
diff --git a/binutils-2.22/gold/target.h b/binutils-2.22/gold/target.h
index a378120..a4aab43 100644
--- a/binutils-2.22/gold/target.h
+++ b/binutils-2.22/gold/target.h
@@ -397,6 +397,11 @@ class Target
   set_osabi(elfcpp::ELFOSABI osabi)
   { this->osabi_ = osabi; }
 
+  // Define target-specific standard symbols.
+  void
+  define_standard_symbols(Symbol_table* symtab, Layout* layout)
+  { this->do_define_standard_symbols(symtab, layout); }
+
  protected:
   // This struct holds the constant information for a child class.  We
   // use a struct to avoid the overhead of virtual function calls for
@@ -630,6 +635,11 @@ class Target
   do_select_as_default_target()
   { }
 
+  // This may be overridden by the child class.
+  virtual void
+  do_define_standard_symbols(Symbol_table*, Layout*)
+  { }
+
  private:
   // The implementations of the four do_make_elf_object virtual functions are
   // almost identical except for their sizes and endianness.  We use a template.
diff --git a/binutils-2.22/gold/testsuite/Makefile.am b/binutils-2.22/gold/testsuite/Makefile.am
index 9b8605b..fdb37e5 100644
--- a/binutils-2.22/gold/testsuite/Makefile.am
+++ b/binutils-2.22/gold/testsuite/Makefile.am
@@ -2483,7 +2483,7 @@ check_SCRIPTS += arm_exidx_test.sh
 check_DATA += arm_exidx_test.stdout
 
 arm_exidx_test.stdout: arm_exidx_test.so
-	$(TEST_READELF) -S $< > $@
+	$(TEST_READELF) -Sr $< > $@
 
 arm_exidx_test.so: arm_exidx_test.o ../ld-new
 	../ld-new -shared -o $@ $<
diff --git a/binutils-2.22/gold/testsuite/arm_exidx_test.s b/binutils-2.22/gold/testsuite/arm_exidx_test.s
index 14dcc94..8e550e4 100644
--- a/binutils-2.22/gold/testsuite/arm_exidx_test.s
+++ b/binutils-2.22/gold/testsuite/arm_exidx_test.s
@@ -23,3 +23,9 @@ empty:
         .fnend
         .size   empty, .-empty
 
+# Check that no dynamic relocations for __exidx_start and __exidx_stop
+# generated.
+	.data
+	.align	12
+	.word	__exidx_start(got)
+	.word	__exidx_end(got)
diff --git a/binutils-2.22/gold/testsuite/arm_exidx_test.sh b/binutils-2.22/gold/testsuite/arm_exidx_test.sh
index f732a68..e196f12 100755
--- a/binutils-2.22/gold/testsuite/arm_exidx_test.sh
+++ b/binutils-2.22/gold/testsuite/arm_exidx_test.sh
@@ -29,10 +29,23 @@ check()
 {
     if ! grep -q "$2" "$1"
     then
-	echo "Did not find section header in $1:"
+	echo "Did not find expected output in $1:"
 	echo "   $2"
 	echo ""
-	echo "Actual headers below:"
+	echo "Actual output below:"
+	cat "$1"
+	exit 1
+    fi
+}
+
+check_not()
+{
+    if grep -q "$2" "$1"
+    then
+	echo "Found unexpected output in $1:"
+	echo "   $2"
+	echo ""
+	echo "Actual output below:"
 	cat "$1"
 	exit 1
     fi
@@ -41,5 +54,7 @@ check()
 # Check that SHF_LINK_ORDER is set.
 check arm_exidx_test.stdout ".* .ARM.exidx .* ARM_EXIDX .* AL .*"
 check arm_exidx_test.stdout ".* .ARM.extab .* PROGBITS .* A .*"
+check_not arm_exidx_test.stdout ".* .* R_ARM_GLOB_DAT .* __exidx_start"
+check_not arm_exidx_test.stdout ".* .* R_ARM_GLOB_DAT .* __exidx_end"
 
 exit 0