An EH patch for gas

An EH patch for gas

[H.J. Lu]

Hi, Ian,

It is wrong to treat all 0x4 as DW_CFA_advance_loc4. .eh_frame can have

	...
	.byte	0x9a
	.byte	0x4
.align 3
	.4byte	length
	...

0x4 here is LEB128 for 0x9a. I believe this patch fixes the bug. Do you
have a better one?

Thanks.

-- 
H.J. Lu (hjl@gnu.org)
---
Sat Aug 29 07:18:45 1998  H.J. Lu  (hjl@gnu.org)

	* as.h (eh_frame_reset): New declaration.

	* ehopt.c (eh_frame_reset): Reset saw_advance_loc4 to 0.

	* read.c (s_align): Call eh_frame_reset ().
	* config/tc-alpha.c (s_alpha_align): Likewise.
	* config/tc-arm.c (s_align): Likewise.
	* config/tc-hppa.c (pa_align): Likewise.
	* config/tc-mips.c (s_align): Likewise.

Index: as.h
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/as.h,v
retrieving revision 1.13
diff -u -p -r1.13 as.h
--- as.h	1998/02/17 20:35:41	1.13
+++ as.h	1998/08/29 13:49:08
@@ -592,6 +592,7 @@ int check_eh_frame PARAMS ((struct expre
 int eh_frame_estimate_size_before_relax PARAMS ((fragS *));
 int eh_frame_relax_frag PARAMS ((fragS *));
 void eh_frame_convert_frag PARAMS ((fragS *));
+void eh_frame_reset PARAMS ((void));
 
 #include "expr.h"		/* Before targ-*.h */
 
Index: ehopt.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/ehopt.c,v
retrieving revision 1.3
diff -u -p -r1.3 ehopt.c
--- ehopt.c	1998/03/31 22:25:05	1.3
+++ ehopt.c	1998/08/29 14:14:30
@@ -243,6 +243,16 @@ eh_frame_code_alignment ()
   return code_alignment;
 }
 
+static int saw_advance_loc4;
+
+/* This functon is called from various functions which handle ".align".
+   A .align marks the end of an FDE entry. */
+void
+eh_frame_reset ()
+{
+  saw_advance_loc4 = 0;
+}
+
 /* This function is called from emit_expr.  It looks for cases which
    we can optimize.
 
@@ -261,7 +271,6 @@ check_eh_frame (exp, pnbytes)
      expressionS *exp;
      unsigned int *pnbytes;
 {
-  static int saw_advance_loc4;
   static fragS *loc4_frag;
   static int loc4_fix;
 
Index: read.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/read.c,v
retrieving revision 1.15
diff -u -p -r1.15 read.c
--- read.c	1998/05/27 16:38:41	1.15
+++ read.c	1998/08/29 13:48:30
@@ -1216,6 +1216,8 @@ s_align (arg, bytes_p)
   int max;
   int fill_p;
 
+  eh_frame_reset ();
+
   if (flag_mri)
     stop = mri_comment_field (&stopc);
 
Index: config/tc-alpha.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/config/tc-alpha.c,v
retrieving revision 1.11
diff -u -p -r1.11 tc-alpha.c
--- config/tc-alpha.c	1998/03/04 17:58:19	1.11
+++ config/tc-alpha.c	1998/08/29 14:04:53
@@ -4161,6 +4161,8 @@ s_alpha_align (ignore)
   char fill, *pfill;
   long max_alignment = 15;
 
+  eh_frame_reset ();
+
   align = get_absolute_expression ();
   if (align > max_alignment)
     {
Index: config/tc-arm.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/config/tc-arm.c,v
retrieving revision 1.17
diff -u -p -r1.17 tc-arm.c
--- config/tc-arm.c	1998/06/29 15:37:06	1.17
+++ config/tc-arm.c	1998/08/29 14:09:10
@@ -1166,6 +1166,8 @@ s_align (unused)	/* Same as s_align_ptwo
   register long temp_fill;
   long max_alignment = 15;
 
+  eh_frame_reset ();
+
   temp = get_absolute_expression ();
   if (temp > max_alignment)
     as_bad ("Alignment too large: %d. assumed.", temp = max_alignment);
Index: config/tc-hppa.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/config/tc-hppa.c,v
retrieving revision 1.1.1.24
diff -u -p -r1.1.1.24 tc-hppa.c
--- config/tc-hppa.c	1997/10/25 21:55:39	1.1.1.24
+++ config/tc-hppa.c	1998/08/29 14:09:45
@@ -4026,6 +4026,8 @@ pa_parse_neg_add_cmpltr (s, isbranch)
 static void
 pa_align (bytes)
 {
+  eh_frame_reset ();
+
   /* We must have a valid space and subspace.  */
   pa_check_current_space_and_subspace ();
 
Index: config/tc-mips.c
===================================================================
RCS file: /home/work/cvs/gnu/binutils/gas/config/tc-mips.c,v
retrieving revision 1.31
diff -u -p -r1.31 tc-mips.c
--- config/tc-mips.c	1998/03/25 17:09:26	1.31
+++ config/tc-mips.c	1998/08/29 14:10:47
@@ -9595,6 +9595,8 @@ s_align (x)
   register long temp_fill;
   long max_alignment = 15;
 
+  eh_frame_reset ();
+
   /*
 
     o  Note that the assembler pulls down any immediately preceeding label

Re: An EH patch for gas

[Ian Lance Taylor]

   From: hjl@lucon.org (H.J. Lu)
   Date: Sat, 29 Aug 1998 07:26:42 -0700 (PDT)

   It is wrong to treat all 0x4 as DW_CFA_advance_loc4. .eh_frame can have

	   ...
	   .byte	0x9a
	   .byte	0x4
   .align 3
	   .4byte	length
	   ...

   0x4 here is LEB128 for 0x9a. I believe this patch fixes the bug. Do you
   have a better one?

Could you please send a complete test case?  Your last test case was
only a partial file.

I don't know what the alignment is doing there, unless the 4 is at the
very end of an FDE.  If that is the case, the correct patch is not the
look for .align directives, but instead to pay attention to the length
of the FDE.

Ian