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[gold patch] Fix PR gold/12220 where linker script causes internal error with compressed debug sections

Cary Coutant ccoutant@google.com
Tue Nov 16 18:49:00 GMT 2010 
> If the code takes this path, it should free the allocated memory after
> the call to this->namepool_.add_with_length.
>
> Also now please remove the handling of is_compressed_debug_section in
> Layout::output_section_name.

Oops! I meant to remove that.

Here's the patch as committed. (Sorry, I forgot to include ChangeLog
in the commit, and had to commit it separately.)

-cary

        PR gold/12220
        * layout.cc (Layout::choose_output_section): Transform names of
        compressed sections even when using a script with a SECTIONS clause.
        (Layout::output_section_name): Remove code to transform
        compressed debug section names.
        * output.cc (Output_section::add_input_section): Use uncompressed
        section size when tracking input sections.
-------------- next part --------------
Index: layout.cc
===================================================================
RCS file: /cvs/src/src/gold/layout.cc,v
retrieving revision 1.186
diff -u -p -r1.186 layout.cc
--- layout.cc	9 Nov 2010 07:56:10 -0000	1.186
+++ layout.cc	16 Nov 2010 18:31:20 -0000
@@ -288,6 +288,30 @@ is_lines_only_debug_section(const char* 
   return false;
 }
 
+// Sometimes we compress sections.  This is typically done for
+// sections that are not part of normal program execution (such as
+// .debug_* sections), and where the readers of these sections know
+// how to deal with compressed sections.  This routine doesn't say for
+// certain whether we'll compress -- it depends on commandline options
+// as well -- just whether this section is a candidate for compression.
+// (The Output_compressed_section class decides whether to compress
+// a given section, and picks the name of the compressed section.)
+
+static bool
+is_compressible_debug_section(const char* secname)
+{
+  return (is_prefix_of(".debug", secname));
+}
+
+// We may see compressed debug sections in input files.  Return TRUE
+// if this is the name of a compressed debug section.
+
+bool
+is_compressed_debug_section(const char* secname)
+{
+  return (is_prefix_of(".zdebug", secname));
+}
+
 // Whether to include this section in the link.
 
 template<int size, bool big_endian>
@@ -581,10 +605,24 @@ Layout::choose_output_section(const Relo
 
   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
 
+  size_t len = strlen(name);
+  char* uncompressed_name = NULL;
+
+  // Compressed debug sections should be mapped to the corresponding
+  // uncompressed section.
+  if (is_compressed_debug_section(name))
+    {
+      uncompressed_name = new char[len];
+      uncompressed_name[0] = '.';
+      gold_assert(name[0] == '.' && name[1] == 'z');
+      strncpy(&uncompressed_name[1], &name[2], len - 2);
+      uncompressed_name[len - 1] = '\0';
+      len -= 1;
+      name = uncompressed_name;
+    }
+
   // Turn NAME from the name of the input section into the name of the
   // output section.
-
-  size_t len = strlen(name);
   if (is_input_section
       && !this->script_options_->saw_sections_clause()
       && !parameters->options().relocatable())
@@ -593,6 +631,9 @@ Layout::choose_output_section(const Relo
   Stringpool::Key name_key;
   name = this->namepool_.add_with_length(name, len, true, &name_key);
 
+  if (uncompressed_name != NULL)
+    delete[] uncompressed_name;
+
   // Find or make the output section.  The output section is selected
   // based on the section name, type, and flags.
   return this->get_output_section(name, name_key, type, flags, order, is_relro);
@@ -925,30 +966,6 @@ Layout::section_flags_to_segment(elfcpp:
   return ret;
 }
 
-// Sometimes we compress sections.  This is typically done for
-// sections that are not part of normal program execution (such as
-// .debug_* sections), and where the readers of these sections know
-// how to deal with compressed sections.  This routine doesn't say for
-// certain whether we'll compress -- it depends on commandline options
-// as well -- just whether this section is a candidate for compression.
-// (The Output_compressed_section class decides whether to compress
-// a given section, and picks the name of the compressed section.)
-
-static bool
-is_compressible_debug_section(const char* secname)
-{
-  return (is_prefix_of(".debug", secname));
-}
-
-// We may see compressed debug sections in input files.  Return TRUE
-// if this is the name of a compressed debug section.
-
-bool
-is_compressed_debug_section(const char* secname)
-{
-  return (is_prefix_of(".zdebug", secname));
-}
-
 // Make a new Output_section, and attach it to segments as
 // appropriate.  ORDER is the order in which this section should
 // appear in the output segment.  IS_RELRO is true if this is a relro
@@ -3924,20 +3941,6 @@ Layout::output_section_name(const char* 
 	}
     }
 
-  // Compressed debug sections should be mapped to the corresponding
-  // uncompressed section.
-  if (is_compressed_debug_section(name))
-    {
-      size_t len = strlen(name);
-      char* uncompressed_name = new char[len];
-      uncompressed_name[0] = '.';
-      gold_assert(name[0] == '.' && name[1] == 'z');
-      strncpy(&uncompressed_name[1], &name[2], len - 2);
-      uncompressed_name[len - 1] = '\0';
-      *plen = len - 1;
-      return uncompressed_name;
-    }
-
   return name;
 }
 
Index: output.cc
===================================================================
RCS file: /cvs/src/src/gold/output.cc,v
retrieving revision 1.137
diff -u -p -r1.137 output.cc
--- output.cc	29 Oct 2010 20:49:20 -0000	1.137
+++ output.cc	16 Nov 2010 18:31:20 -0000
@@ -2165,7 +2165,7 @@ Output_section::add_input_section(Layout
       || parameters->target().may_relax()
       || parameters->options().section_ordering_file())
     {
-      Input_section isecn(object, shndx, shdr.get_sh_size(), addralign);
+      Input_section isecn(object, shndx, input_section_size, addralign);
       if (parameters->options().section_ordering_file())
         {
           unsigned int section_order_index =
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