From ad0fc6987804eb16dccee061dc63fdd6ca07be48 Mon Sep 17 00:00:00 2001
From: Jim Wilson <wilson@redhat.com>
Date: Tue, 27 Mar 2001 23:15:04 +0000
Subject: [PATCH] Fix ia64-linux kernel miscompile, bad unwind info when
 reorder epilogue block.

	* final.c (final_scan_insn, case NOTE_INSN_BASIC_BLOCK): Call
	IA64_UNWIND_EMIT.
	* config/ia64/ia64.c (block_num, need_copy_state): New static vars.
	(process_epilogue): New static function.
	(process_set): Call process_epilogue instead of emitting .restore
	directly.
	(process_for_unwind_directive): Handle NOTE_INSN_BASIC_BLOCK.

From-SVN: r40885
---
 gcc/ChangeLog          |  8 +++++++
 gcc/config/ia64/ia64.c | 53 +++++++++++++++++++++++++++++++++++++-----
 gcc/final.c            |  3 +++
 3 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 22b2f62bd37..7aa2bdeccc6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -7,6 +7,14 @@
 
 2001-03-27  Jim Wilson  <wilson@redhat.com>
 
+	* final.c (final_scan_insn, case NOTE_INSN_BASIC_BLOCK): Call
+	IA64_UNWIND_EMIT.
+	* config/ia64/ia64.c (block_num, need_copy_state): New static vars.
+	(process_epilogue): New static function.
+	(process_set): Call process_epilogue instead of emitting .restore
+	directly.
+	(process_for_unwind_directive): Handle NOTE_INSN_BASIC_BLOCK.
+
 	* flow.c (struct reg_cond_life_info): New fields orig_condition
 	and stores.
 	(init_propagate_block_info): Set new fields.
diff --git a/gcc/config/ia64/ia64.c b/gcc/config/ia64/ia64.c
index 3d30ff872e6..63d830de216 100644
--- a/gcc/config/ia64/ia64.c
+++ b/gcc/config/ia64/ia64.c
@@ -6335,7 +6335,32 @@ ia64_encode_section_info (decl)
     }
 }
 
-/* Output assmebly directives for prologue regions.  */
+/* Output assembly directives for prologue regions.  */
+
+/* The current basic block number.  */
+
+static int block_num;
+
+/* True if we need a copy_state command at the start of the next block.  */
+
+static int need_copy_state;
+
+/* The function emits unwind directives for the start of an epilogue.  */
+
+static void
+process_epilogue ()
+{
+  /* If this isn't the last block of the function, then we need to label the
+     current state, and copy it back in at the start of the next block.  */
+
+  if (block_num != n_basic_blocks - 1)
+    {
+      fprintf (asm_out_file, "\t.label_state 1\n");
+      need_copy_state = 1;
+    }
+
+  fprintf (asm_out_file, "\t.restore sp\n");
+}
 
 /* This function processes a SET pattern looking for specific patterns
    which result in emitting an assembly directive required for unwinding.  */
@@ -6383,14 +6408,14 @@ process_set (asm_out_file, pat)
 		  fputc ('\n', asm_out_file);
 		}
 	      else
-		fprintf (asm_out_file, "\t.restore sp\n");
+		process_epilogue ();
 	    }
 	  else
 	    abort ();
 	}
       else if (GET_CODE (src) == REG
 	       && REGNO (src) == HARD_FRAME_POINTER_REGNUM)
-	fprintf (asm_out_file, "\t.restore sp\n");
+	process_epilogue ();
       else
 	abort ();
 
@@ -6561,12 +6586,28 @@ process_for_unwind_directive (asm_out_file, insn)
      FILE *asm_out_file;
      rtx insn;
 {
-  if ((flag_unwind_tables
-       || (flag_exceptions && !exceptions_via_longjmp))
-      && RTX_FRAME_RELATED_P (insn))
+  if (flag_unwind_tables
+      || (flag_exceptions && !exceptions_via_longjmp))
     {
       rtx pat;
 
+      if (GET_CODE (insn) == NOTE
+	  && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK)
+	{
+	  block_num = NOTE_BASIC_BLOCK (insn)->index;
+
+	  /* Restore unwind state from immediately before the epilogue.  */
+	  if (need_copy_state)
+	    {
+	      fprintf (asm_out_file, "\t.body\n");
+	      fprintf (asm_out_file, "\t.copy_state 1\n");
+	      need_copy_state = 0;
+	    }
+	}
+
+      if (! RTX_FRAME_RELATED_P (insn))
+	return;
+
       pat = find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX);
       if (pat)
 	pat = XEXP (pat, 0);
diff --git a/gcc/final.c b/gcc/final.c
index 402ff8c2272..cdc2de49c5a 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -2117,6 +2117,9 @@ final_scan_insn (insn, file, optimize, prescan, nopeepholes)
 	  break;
 
 	case NOTE_INSN_BASIC_BLOCK:
+#ifdef IA64_UNWIND_INFO
+	  IA64_UNWIND_EMIT (asm_out_file, insn);
+#endif
 	  if (flag_debug_asm)
 	    fprintf (asm_out_file, "\t%s basic block %d\n",
 		     ASM_COMMENT_START, NOTE_BASIC_BLOCK (insn)->index);
-- 
2.30.2