Add an option to objcopy to change the alignment of sections.

PR 24942
	* objcopy.c (SECTION_CONTEXT_SET_ALIGNMENT): New constant.
	(struct section_list): Add alignment field.
	(command_line_switch): Add OPTION_SET_SECTION_ALIGNMENT.
	(copy_options): Add --set-section-alignment.
	(copy_usage): Describe --set-section-alignment.
	(find_section_list): Initialise the alignment field.
	(setup_section): Handle the alignment field.
	(copy_main): Handle OPTION_SET_SECTION_ALIGNMENT.
	* doc/binutils.texi: Document the new feature.
	* NEWS: Mention the new feature.

binutils/ChangeLog

@@ -1,3 +1,17 @@
+2019-08-28  Niklas Gürtler  <profclonk@gmail.com>
+
+	PR 24942
+	* objcopy.c (SECTION_CONTEXT_SET_ALIGNMENT): New constant.
+	(struct section_list): Add alignment field.
+	(command_line_switch): Add OPTION_SET_SECTION_ALIGNMENT.
+	(copy_options): Add --set-section-alignment.
+	(copy_usage): Describe --set-section-alignment.
+	(find_section_list): Initialise the alignment field.
+	(setup_section): Handle the alignment field.
+	(copy_main): Handle OPTION_SET_SECTION_ALIGNMENT.
+	* doc/binutils.texi: Document the new feature.
+	* NEWS: Mention the new feature.
+
 2019-08-28  Nick Clifton  <nickc@redhat.com>
 
 	PR 24931

binutils/NEWS

@@ -2,6 +2,9 @@
 * Add --source-comment[=<txt>] option to objdump which if present,
   provides a prefix to source code lines displayed in a disassembly.
 
+* Add --set-section-alignment <section-name>=<align> option to objcopy to allow
+  the changing of section alignments.
+
 * Add --verilog-data-width option to objcopy for verilog targets to control
   width of data elements in verilog hex format.
 

binutils/doc/binutils.texi

@@ -1175,6 +1175,7 @@ objcopy [@option{-F} @var{bfdname}|@option{--target=}@var{bfdname}]
         [@option{--change-section-vma} @var{sectionpattern}@{=,+,-@}@var{val}]
         [@option{--change-warnings}] [@option{--no-change-warnings}]
         [@option{--set-section-flags} @var{sectionpattern}=@var{flags}]
+        [@option{--set-section-alignment} @var{sectionpattern}=@var{align}]
         [@option{--add-section} @var{sectionname}=@var{filename}]
         [@option{--dump-section} @var{sectionname}=@var{filename}]
         [@option{--update-section} @var{sectionname}=@var{filename}]
@@ -1620,6 +1621,11 @@ to clear the @samp{contents} flag of a section which does have
 contents--just remove the section instead.  Not all flags are
 meaningful for all object file formats.
 
+@item --set-section-alignment @var{sectionpattern}=@var{align}
+Set the alignment for any sections matching @var{sectionpattern}.  @var{align}
+specifies the alignment as the exponent for the power of two, i.e. the
+alignment in bytes will be 2^@var{align}.
+
 @item --add-section @var{sectionname}=@var{filename}
 Add a new section named @var{sectionname} while copying the file.  The
 contents of the new section are taken from the file @var{filename}.  The
@@ -1975,8 +1981,9 @@ for dlls.
 [This option is specific to PE targets.]
 
 @item --section-alignment @var{num}
-Sets the section alignment.  Sections in memory will always begin at
-addresses which are a multiple of this number.  Defaults to 0x1000.
+Sets the section alignment field in the PE header.  Sections in memory
+will always begin at addresses which are a multiple of this number.
+Defaults to 0x1000.
 [This option is specific to PE targets.]
 
 @item --stack @var{reserve}

binutils/objcopy.c

@@ -143,10 +143,12 @@ struct section_list
 #define SECTION_CONTEXT_ALTER_LMA (1 << 5) /* Increment or decrement the section's LMA address.  */
 #define SECTION_CONTEXT_SET_FLAGS (1 << 6) /* Set the section's flags.  */
 #define SECTION_CONTEXT_REMOVE_RELOCS (1 << 7) /* Remove relocations for this section.  */
+#define SECTION_CONTEXT_SET_ALIGNMENT (1 << 8) /* Set alignment for section.  */
 
   bfd_vma		vma_val;   /* Amount to change by or set to.  */
   bfd_vma		lma_val;   /* Amount to change by or set to.  */
   flagword		flags;	   /* What to set the section flags to.	 */
+  unsigned int	        alignment; /* Alignment of output section.  */
 };
 
 static struct section_list *change_sections;
@@ -344,8 +346,9 @@ enum command_line_switch
   OPTION_REMOVE_RELOCS,
   OPTION_RENAME_SECTION,
   OPTION_REVERSE_BYTES,
-  OPTION_SECTION_ALIGNMENT,
+  OPTION_PE_SECTION_ALIGNMENT,
   OPTION_SET_SECTION_FLAGS,
+  OPTION_SET_SECTION_ALIGNMENT,
   OPTION_SET_START,
   OPTION_SREC_FORCES3,
   OPTION_SREC_LEN,
@@ -476,8 +479,9 @@ static struct option copy_options[] =
   {"remove-relocations", required_argument, 0, OPTION_REMOVE_RELOCS},
   {"rename-section", required_argument, 0, OPTION_RENAME_SECTION},
   {"reverse-bytes", required_argument, 0, OPTION_REVERSE_BYTES},
-  {"section-alignment", required_argument, 0, OPTION_SECTION_ALIGNMENT},
+  {"section-alignment", required_argument, 0, OPTION_PE_SECTION_ALIGNMENT},
   {"set-section-flags", required_argument, 0, OPTION_SET_SECTION_FLAGS},
+  {"set-section-alignment", required_argument, 0, OPTION_SET_SECTION_ALIGNMENT},
   {"set-start", required_argument, 0, OPTION_SET_START},
   {"srec-forceS3", no_argument, 0, OPTION_SREC_FORCES3},
   {"srec-len", required_argument, 0, OPTION_SREC_LEN},
@@ -610,6 +614,8 @@ copy_usage (FILE *stream, int exit_status)
                                    Warn if a named section does not exist\n\
      --set-section-flags <name>=<flags>\n\
                                    Set section <name>'s properties to <flags>\n\
+     --set-section-alignment <name>=<align>\n\
+                                   Set section <name>'s alignment to 2^<align> bytes\n\
      --add-section <name>=<file>   Add section <name> found in <file> to output\n\
      --update-section <name>=<file>\n\
                                    Update contents of section <name> with\n\
@@ -964,6 +970,7 @@ find_section_list (const char *name, bfd_boolean add, unsigned int context)
   p->vma_val = 0;
   p->lma_val = 0;
   p->flags = 0;
+  p->alignment = 0;
   p->next = change_sections;
   change_sections = p;
 
@@ -3766,6 +3773,7 @@ setup_section (bfd *ibfd, sec_ptr isection, void *obfdarg)
   const char * name;
   char *prefix = NULL;
   bfd_boolean make_nobits;
+  unsigned int alignment;
 
   if (is_strip_section (ibfd, isection))
     return;
@@ -3872,11 +3880,18 @@ setup_section (bfd *ibfd, sec_ptr isection, void *obfdarg)
 
   osection->lma = lma;
 
+  p = find_section_list (bfd_section_name (ibfd, isection), FALSE,
+			 SECTION_CONTEXT_SET_ALIGNMENT);
+  if (p != NULL)
+    alignment = p->alignment;
+  else
+    alignment = bfd_section_alignment (ibfd, isection);
+  
   /* FIXME: This is probably not enough.  If we change the LMA we
      may have to recompute the header for the file as well.  */
   if (!bfd_set_section_alignment (obfd,
 				  osection,
-				  bfd_section_alignment (ibfd, isection)))
+				  alignment))
     {
       err = _("failed to set alignment");
       goto loser;
@@ -5262,6 +5277,33 @@ copy_main (int argc, char *argv[])
 	  }
 	  break;
 
+	case OPTION_SET_SECTION_ALIGNMENT:
+	  {
+	    struct section_list *p;
+	    const char *s;
+	    int len;
+	    char *name;
+	    int align;
+
+	    s = strchr (optarg, '=');
+	    if (s == NULL)
+	      fatal (_("bad format for %s"), "--set-section-alignment");
+	    
+	    align = atoi(s+1);
+	    if (align < 0)
+	      fatal (_("bad format for %s"), "--set-section-alignment");
+
+	    len = s - optarg;
+	    name = (char *) xmalloc (len + 1);
+	    strncpy (name, optarg, len);
+	    name[len] = '\0';
+
+	    p = find_section_list (name, TRUE, SECTION_CONTEXT_SET_ALIGNMENT);
+
+	    p->alignment = align;
+	  }
+	  break;
+	  
 	case OPTION_RENAME_SECTION:
 	  {
 	    flagword flags;
@@ -5457,7 +5499,7 @@ copy_main (int argc, char *argv[])
 	  pe_image_base = parse_vma (optarg, "--image-base");
 	  break;
 
-	case OPTION_SECTION_ALIGNMENT:
+	case OPTION_PE_SECTION_ALIGNMENT:
 	  pe_section_alignment = parse_vma (optarg,
 					    "--section-alignment");
 	  break;