adjust mach-o default GAS sections.

gas:

	* as.c (perform_an_assembly_pass): Do not create text, data and bss
	sections for MACH-O.  Do not switch to the text section.
	* config/obj-macho.c (obj_mach_o_segT_from_bfd_name): Forward decl.
	(mach_o_begin): Startup with only text section unless suppressed.
	* config/obj-macho.h (obj_begin): define to mach_o_begin ().

gas/testsuite:

	* gas/mach-o/sections-1.d: Amend to recognize that bss is not emitted
	by default.
	* gas/mach-o/sections-2.d: New.

7 files changed, 69 insertions, 8 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 30ff4fb..26e4fc5 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,11 @@
+2011-12-29  Iain Sandoe  <idsandoe@googlemail.com>
+
+	* as.c (perform_an_assembly_pass): Do not create text, data and bss
+	sections for MACH-O.  Do not switch to the text section.
+	* config/obj-macho.c (obj_mach_o_segT_from_bfd_name): Forward decl.
+	(mach_o_begin): Startup with only text section unless suppressed.
+	* config/obj-macho.h (obj_begin): define to mach_o_begin ().
+
 2011-12-22  DJ Delorie  <dj@redhat.com>
 
 	* config/rl78-defs.h (rl78_linkrelax_addr16): Add.
diff --git a/gas/as.c b/gas/as.c
index b99ea1e..1325038 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -1037,10 +1037,13 @@ static void
 perform_an_assembly_pass (int argc, char ** argv)
 {
   int saw_a_file = 0;
+#ifndef OBJ_MACH_O
   flagword applicable;
+#endif
 
   need_pass_2 = 0;
 
+#ifndef OBJ_MACH_O
   /* Create the standard sections, and those the assembler uses
      internally.  */
   text_section = subseg_new (TEXT_SECTION_NAME, 0);
@@ -1057,12 +1060,15 @@ perform_an_assembly_pass (int argc, char ** argv)
 				       | SEC_DATA));
   bfd_set_section_flags (stdoutput, bss_section, applicable & SEC_ALLOC);
   seg_info (bss_section)->bss = 1;
+#endif
   subseg_new (BFD_ABS_SECTION_NAME, 0);
   subseg_new (BFD_UND_SECTION_NAME, 0);
   reg_section = subseg_new ("*GAS `reg' section*", 0);
   expr_section = subseg_new ("*GAS `expr' section*", 0);
 
+#ifndef OBJ_MACH_O
   subseg_set (text_section, 0);
+#endif
 
   /* This may add symbol table entries, which requires having an open BFD,
      and sections already created.  */
diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index be1c9ff..74fb0c9 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -45,13 +45,40 @@
 #include "mach-o/loader.h"
 #include "obj-macho.h"
 
+/* Forward decl.  */
+static segT obj_mach_o_segT_from_bfd_name (const char *nam, int must_succeed);
+
 /* TODO: Implement "-dynamic"/"-static" command line options.  */
 
 static int obj_mach_o_is_static;
 
+/* TODO: Implement the "-n" command line option to suppress the initial
+   switch to the text segment.  */
+static int obj_mach_o_start_with_text_section = 1;
+
 /* Allow for special re-ordering on output.  */
 
-static int seen_objc_section;
+static int obj_mach_o_seen_objc_section;
+
+/* Start-up: At present, just create the sections we want.  */
+void
+mach_o_begin (void)
+{
+  /* Mach-O only defines the .text section by default, and even this can
+     be suppressed by a flag.  In the latter event, the first code MUST
+     be a section definition.  */
+  if (obj_mach_o_start_with_text_section)
+    {
+      text_section = obj_mach_o_segT_from_bfd_name (TEXT_SECTION_NAME, 1);
+      subseg_set (text_section, 0);
+      if (obj_mach_o_is_static)
+	{
+	  bfd_mach_o_section *mo_sec 
+			= bfd_mach_o_get_mach_o_section (text_section);
+	  mo_sec->flags &= ~BFD_MACH_O_S_ATTR_PURE_INSTRUCTIONS;
+	}
+    }
+}
 
 /* Remember the subsections_by_symbols state in case we need to reset
    the file flags.  */
@@ -473,8 +500,9 @@ obj_mach_o_objc_section (int sect_index)
   section = obj_mach_o_segT_from_bfd_name (objc_sections[sect_index], 1);
   if (section != NULL)
     {
-      seen_objc_section = 1; /* We need to ensure that certain sections are
-				present and in the right order.  */
+      obj_mach_o_seen_objc_section = 1; /* We need to ensure that certain
+					   sections are present and in the
+					   right order.  */
       subseg_set (section, 0);
     }
 
diff --git a/gas/config/obj-macho.h b/gas/config/obj-macho.h
index 94c1cde..d9b0b33 100644
--- a/gas/config/obj-macho.h
+++ b/gas/config/obj-macho.h
@@ -30,6 +30,10 @@
 
 #define OUTPUT_FLAVOR bfd_target_mach_o_flavour
 
+/* We want to control how the sections are pre-defined on startup.  */
+#define obj_begin() mach_o_begin ()
+extern void mach_o_begin (void);
+
 /* All our align expressions are power of two.  */
 #define USE_ALIGN_PTWO
 
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index 723b8c4..80f9a73 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-29  Iain Sandoe  <idsandoe@googlemail.com>
+
+	* gas/mach-o/sections-1.d: Amend to recognize that bss is not emitted
+	by default.
+	* gas/mach-o/sections-2.d: New.
+
 2011-12-19  Iain Sandoe  <idsandoe@googlemail.com>
 
 	* gas/mach-o/err-sections-1.s: New.
diff --git a/gas/testsuite/gas/mach-o/sections-1.d b/gas/testsuite/gas/mach-o/sections-1.d
index a70af9b..5b8a8fa 100644
--- a/gas/testsuite/gas/mach-o/sections-1.d
+++ b/gas/testsuite/gas/mach-o/sections-1.d
@@ -11,11 +11,6 @@
   align: 0  nreloc: 0  reloff: (00000000)?00000000
   flags: 00000000 \(type: regular attr: -\)
   reserved1: 0x0  reserved2: 0x0  reserved3: 0x0
- Section: __bss            __DATA           \(bfdname: .bss\)
-  addr: (00000000)?00000000 size: (00000000)?00000000 offset: (00000000)?00000000
-  align: 0  nreloc: 0  reloff: (00000000)?00000000
-  flags: 00000001 \(type: zerofill attr: -\)
-  reserved1: 0x0  reserved2: 0x0  reserved3: 0x0
  Section: __textcoal_nt    __TEXT           \(bfdname: __TEXT.__textcoal_nt\)
   addr: (00000000)?00000000 size: (00000000)?00000000 offset: (00000000)?00000000
   align: 0  nreloc: 0  reloff: (00000000)?00000000
diff --git a/gas/testsuite/gas/mach-o/sections-2.d b/gas/testsuite/gas/mach-o/sections-2.d
new file mode 100644
index 0000000..9d24f9a
--- /dev/null
+++ b/gas/testsuite/gas/mach-o/sections-2.d
@@ -0,0 +1,14 @@
+#objdump: -h
+#source: empty.s
+# we should only see a text section by default.
+.*: +file format mach-o.*
+#...
+Idx Name.*
+  0 .text.*
+.*
+#failif
+  1 .data.*
+.*
+  2 .bss.*
+.*
+