[PATCH] Support .eh_frame augmentation S flag (signal frame)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

This patch corresponds to the GCC patch I committed earlier today.
Ok for trunk?

2006-02-27  Jakub Jelinek  <jakub@redhat.com>

bfd/
	* elf-eh-frame.c (_bfd_elf_discard_section_eh_frame): Handle S flag.
	(_bfd_elf_write_section_eh_frame): Likewise.
gas/
	* dw2gencfi.c (struct fde_entry, struct cie_entry): Add signal_frame
	field.
	(CFI_signal_frame): Define.
	(cfi_pseudo_table): Add .cfi_signal_frame.
	(dot_cfi): Handle CFI_signal_frame.
	(output_cie): Handle cie->signal_frame.
	(select_cie_for_fde): Don't share CIE if signal_frame flag is
	different.  Copy signal_frame from FDE to newly created CIE.
	* doc/as.texinfo: Document .cfi_signal_frame.

--- gas/dw2gencfi.c.jj	2005-12-14 13:50:34.000000000 +0100
+++ gas/dw2gencfi.c	2006-02-24 18:59:30.000000000 +0100
@@ -1,5 +1,5 @@
 /* dw2gencfi.c - Support for generating Dwarf2 CFI information.
-   Copyright 2003, 2004, 2005 Free Software Foundation, Inc.
+   Copyright 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
    Contributed by Michal Ludvig <mludvig@suse.cz>
 
    This file is part of GAS, the GNU Assembler.
@@ -88,6 +88,7 @@ struct fde_entry
   struct cfi_insn_data *data;
   struct cfi_insn_data **last;
   unsigned int return_column;
+  unsigned int signal_frame;
 };
 
 struct cie_entry
@@ -95,6 +96,7 @@ struct cie_entry
   struct cie_entry *next;
   symbolS *start_address;
   unsigned int return_column;
+  unsigned int signal_frame;
   struct cfi_insn_data *first, *last;
 };
 
@@ -354,6 +356,7 @@ static void dot_cfi_endproc (int);
 #define CFI_return_column	0x101
 #define CFI_rel_offset		0x102
 #define CFI_escape		0x103
+#define CFI_signal_frame	0x104
 
 const pseudo_typeS cfi_pseudo_table[] =
   {
@@ -374,6 +377,7 @@ const pseudo_typeS cfi_pseudo_table[] =
     { "cfi_restore_state", dot_cfi, DW_CFA_restore_state },
     { "cfi_window_save", dot_cfi, DW_CFA_GNU_window_save },
     { "cfi_escape", dot_cfi_escape, 0 },
+    { "cfi_signal_frame", dot_cfi, CFI_signal_frame },
     { NULL, NULL, 0 }
   };
 
@@ -547,6 +551,10 @@ dot_cfi (int arg)
       cfi_add_CFA_insn (DW_CFA_GNU_window_save);
       break;
 
+    case CFI_signal_frame:
+      cur_fde_data->signal_frame = 1;
+      break;
+
     default:
       abort ();
     }
@@ -864,6 +872,8 @@ output_cie (struct cie_entry *cie)
   out_one (DW_CIE_VERSION);			/* Version.  */
   out_one ('z');				/* Augmentation.  */
   out_one ('R');
+  if (cie->signal_frame)
+    out_one ('S');
   out_one (0);
   out_uleb128 (DWARF2_LINE_MIN_INSN_LENGTH);	/* Code alignment.  */
   out_sleb128 (DWARF2_CIE_DATA_ALIGNMENT);	/* Data alignment.  */
@@ -944,7 +954,8 @@ select_cie_for_fde (struct fde_entry *fd
 
   for (cie = cie_root; cie; cie = cie->next)
     {
-      if (cie->return_column != fde->return_column)
+      if (cie->return_column != fde->return_column
+	  || cie->signal_frame != fde->signal_frame)
 	continue;
       for (i = cie->first, j = fde->data;
 	   i != cie->last && j != NULL;
@@ -1017,6 +1028,7 @@ select_cie_for_fde (struct fde_entry *fd
   cie->next = cie_root;
   cie_root = cie;
   cie->return_column = fde->return_column;
+  cie->signal_frame = fde->signal_frame;
   cie->first = fde->data;
 
   for (i = cie->first; i ; i = i->next)
--- gas/doc/as.texinfo.jj	2005-12-14 13:50:35.000000000 +0100
+++ gas/doc/as.texinfo	2006-02-24 19:04:58.000000000 +0100
@@ -4102,6 +4102,9 @@ using the known displacement of the CFA 
 This is often easier to use, because the number will match the
 code it's annotating.
 
+@section @code{.cfi_signal_frame}
+Mark current function as signal trampoline.
+
 @section @code{.cfi_window_save}
 SPARC register window has been saved.
 
--- bfd/elf-eh-frame.c.jj	2005-05-13 23:44:07.000000000 +0200
+++ bfd/elf-eh-frame.c	2006-02-21 11:34:50.000000000 +0100
@@ -1,5 +1,5 @@
 /* .eh_frame section optimization.
-   Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   Copyright 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
    Written by Jakub Jelinek <jakub@redhat.com>.
 
    This file is part of BFD, the Binary File Descriptor library.
@@ -613,6 +613,8 @@ _bfd_elf_discard_section_eh_frame
 		    ENSURE_NO_RELOCS (buf);
 		    REQUIRE (get_DW_EH_PE_width (cie.fde_encoding, ptr_size));
 		    break;
+		  case 'S':
+		    break;
 		  case 'P':
 		    {
 		      int per_width;
@@ -1178,6 +1180,8 @@ _bfd_elf_write_section_eh_frame (bfd *ab
 		      }
 		    buf++;
 		    break;
+		  case 'S':
+		    break;
 		  default:
 		    BFD_FAIL ();
 		  }

	Jakub