gold patch committed: Fix some elflint problems

[Ian Lance Taylor <iant at google dot com>]

This patch fixes some problems in the gold output as reported by
elflint, which is part of elfutils.  If all input sections have the
SHF_MERGE flag set, set it in the output section, and same for the
SHF_STRING flag.  If all input sections have the same entsize field,
set it in the output section.  Committed to mainline.

Ian


2009-12-29  Ian Lance Taylor  <iant@google.com>

	PR 10450
	* output.h (class Output_section): Add is_entsize_zero_ field.
	* output.cc (Output_section::Output_section): Initialize
	is_entsize_zero_.
	(Output_section::set_entsize): If two different entsizes are
	requested, force it to zero.
	(Output_section::add_input_section): Set flags for .debug_str
	before updating section flags.  Set entsize.
	(Output_section::update_flags_for_input_section): Set SHF_MERGE
	and SHF_STRING if all input sections have those flags.


Index: output.cc
===================================================================
RCS file: /cvs/src/src/gold/output.cc,v
retrieving revision 1.108
diff -p -u -r1.108 output.cc
--- output.cc	17 Dec 2009 00:00:26 -0000	1.108
+++ output.cc	30 Dec 2009 03:58:03 -0000
@@ -1800,6 +1800,7 @@ Output_section::Output_section(const cha
     is_interp_(false),
     is_dynamic_linker_section_(false),
     generate_code_fills_at_write_(false),
+    is_entsize_zero_(false),
     tls_offset_(0),
     checkpoint_(NULL),
     merge_section_map_(),
@@ -1824,10 +1825,15 @@ Output_section::~Output_section()
 void
 Output_section::set_entsize(uint64_t v)
 {
-  if (this->entsize_ == 0)
+  if (this->is_entsize_zero_)
+    ;
+  else if (this->entsize_ == 0)
     this->entsize_ = v;
-  else
-    gold_assert(this->entsize_ == v);
+  else if (this->entsize_ != v)
+    {
+      this->entsize_ = 0;
+      this->is_entsize_zero_ = 1;
+    }
 }
 
 // Add the input section SHNDX, with header SHDR, named SECNAME, in
@@ -1863,8 +1869,6 @@ Output_section::add_input_section(Sized_
     this->addralign_ = addralign;
 
   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
-  this->update_flags_for_input_section(sh_flags);
-
   uint64_t entsize = shdr.get_sh_entsize();
 
   // .debug_str is a mergeable string section, but is not always so
@@ -1875,6 +1879,9 @@ Output_section::add_input_section(Sized_
       entsize = 1;
     }
 
+  this->update_flags_for_input_section(sh_flags);
+  this->set_entsize(entsize);
+
   // If this is a SHF_MERGE section, we pass all the input sections to
   // a Output_data_merge.  We don't try to handle relocations for such
   // a section.  We don't try to handle empty merge sections--they
@@ -2199,6 +2206,22 @@ Output_section::update_flags_for_input_s
 		   & (elfcpp::SHF_WRITE
 		      | elfcpp::SHF_ALLOC
 		      | elfcpp::SHF_EXECINSTR));
+
+  if ((flags & elfcpp::SHF_MERGE) == 0)
+    this->flags_ &=~ elfcpp::SHF_MERGE;
+  else
+    {
+      if (this->current_data_size_for_child() == 0)
+	this->flags_ |= elfcpp::SHF_MERGE;
+    }
+
+  if ((flags & elfcpp::SHF_STRINGS) == 0)
+    this->flags_ &=~ elfcpp::SHF_STRINGS;
+  else
+    {
+      if (this->current_data_size_for_child() == 0)
+	this->flags_ |= elfcpp::SHF_STRINGS;
+    }
 }
 
 // Find the merge section into which an input section with index SHNDX in
Index: output.h
===================================================================
RCS file: /cvs/src/src/gold/output.h,v
retrieving revision 1.91
diff -p -u -r1.91 output.h
--- output.h	17 Dec 2009 00:00:26 -0000	1.91
+++ output.h	30 Dec 2009 03:58:03 -0000
@@ -3352,6 +3352,8 @@ class Output_section : public Output_dat
   bool is_dynamic_linker_section_ : 1;
   // Whether code-fills are generated at write.
   bool generate_code_fills_at_write_ : 1;
+  // Whether the entry size field should be zero.
+  bool is_entsize_zero_ : 1;
   // For SHT_TLS sections, the offset of this section relative to the base
   // of the TLS segment.
   uint64_t tls_offset_;