Re: [RFA] CFI improvements

[Michal Ludvig <mludvig at suse dot cz>]

Hans-Peter Nilsson told me that:
> On Wed, 21 May 2003, Michal Ludvig wrote:
>
> > Hans-Peter Nilsson told me that:
> >
> > > On Tue, 20 May 2003, Michal Ludvig wrote:
> > >
> > > > the attached patch adds some new features to the CFI engine:
> > > > - register names can start with '%' as requested by GCC guys.
> > >
> > > This should be handled by the target's tc_regname_to_dw2regnum,
> > > not in target-independent code.  (No creeping ix86-isms, please.)
> >
> > No problem. Something like this?
>
> Oh, sorry: consider redefining tc_regname_to_dw2regnum to take a
> char ** and to handle incrementing it over the register name.

It's not good a idea because you couldn't pass constant strings to the 
function then. Instead I added another parameter - pointer to 'int' - 
that is filled with the number of characters used. If the 'size' is NULL 
nothing bad happens - the value is simply ignored. After return size can 
be used to adjust input_line_pointer.

Comments? Can I commit this version (Alan)?

Michal Ludvig
--
* SuSE CR, s.r.o     * mludvig@suse.cz
* (+420) 296.545.373 * http://www.suse.cz

2003-05-21  Michal Ludvig  <mludvig@suse.cz>

	* dw2gencfi.c (cfi_parse_arg): Allow registers in more
	generic way. Remove special case for '%'-starting regnames.
	* config/tc-i386.c (tc_x86_regname_to_dw2regnum): Allow
	'%'-starting regnames.
	* testsuite/gas/cfi/cfi-x86_64.s: Test register names 
	starting with '%' and shorter than 3 chars.

Index: dw2gencfi.c
===================================================================
RCS file: /cvs/src/src/gas/dw2gencfi.c,v
retrieving revision 1.4
diff -u -p -r1.4 dw2gencfi.c
--- dw2gencfi.c	21 May 2003 11:31:07 -0000	1.4
+++ dw2gencfi.c	21 May 2003 16:32:37 -0000
@@ -151,20 +151,15 @@ cfi_parse_arg (long *param, int resolver
       retval = 1;
     }
 #ifdef tc_regname_to_dw2regnum
-  else if (resolvereg && ((is_name_beginner (*input_line_pointer))
-			   || (*input_line_pointer == '%'
-			       && is_name_beginner (*(++input_line_pointer)))))
+  else if (resolvereg)
     {
-      char *name, c, *p;
-
-      name = input_line_pointer;
-      c = get_symbol_end ();
-      p = input_line_pointer;
-
-      if ((value = tc_regname_to_dw2regnum (name)) >= 0)
+      int size;
+      
+      if ((value = tc_regname_to_dw2regnum (input_line_pointer, &size)) >= 0)
+      {
 	retval = 1;
-
-      *p = c;
+	input_line_pointer += size;
+      }
     }
 #endif
   else
Index: config/tc-i386.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-i386.c,v
retrieving revision 1.139
diff -u -p -r1.139 tc-i386.c
--- config/tc-i386.c	20 May 2003 07:58:06 -0000	1.139
+++ config/tc-i386.c	21 May 2003 16:32:38 -0000
@@ -6329,10 +6329,11 @@ tc_x86_cfi_init (void)
 }
 
 unsigned long
-tc_x86_regname_to_dw2regnum (const char *regname)
+tc_x86_regname_to_dw2regnum (char *regname, int *size)
 {
   unsigned int regnum;
   unsigned int regnames_count;
+  unsigned int percent_flag = 0, name_len;
   char *regnames_32[] =
     {
       "eax", "ebx", "ecx", "edx",
@@ -6347,24 +6348,52 @@ tc_x86_regname_to_dw2regnum (const char 
       "r12", "r13", "r14", "r15",
       "rip"
     };
-  char **regnames;
+  char **regnames, *p, c;
 
   if (flag_code == CODE_64BIT)
     {
       regnames = regnames_64;
-      regnames_count = sizeof (regnames_64);
+      regnames_count = sizeof (regnames_64) / sizeof (void*);
     }
   else
     {
       regnames = regnames_32;
-      regnames_count = sizeof (regnames_32);
+      regnames_count = sizeof (regnames_32) / sizeof (void*);
     }
 
+  percent_flag = (*regname == '%');
+  regname += percent_flag;
+
+  p = regname;
+  while ((*p >= 'a' && *p <= 'z') 
+	 || (*p >= 'A' && *p <= 'Z')
+	 || (*p >= '0' && *p <= '9'))
+    p++;
+
+  /* Save char at *p only when it isn't \0.  */
+  if (*p)
+  {
+    c = *p;
+    *p = 0;
+  }
+  
+  name_len = p - regname;
+  
   for (regnum = 0; regnum < regnames_count; regnum++)
     if (strcmp (regname, regnames[regnum]) == 0)
+    {
+      if (size)
+	*size = percent_flag + name_len;
+      if (c)
+	*p = c;
       return regnum;
+    }
 
   as_bad (_("unknown register name '%s'"), regname);
+  if (size)
+    *size = percent_flag + name_len;
+  if (c)
+    *p = c;
   return -1;
 }
 
@@ -6373,12 +6402,12 @@ tc_x86_frame_initial_instructions (void)
 {
   if (flag_code == CODE_64BIT)
     {
-      cfi_add_insn (CFA_def_cfa, tc_x86_regname_to_dw2regnum ("rsp"), 8);
-      cfi_add_insn (CFA_offset, tc_x86_regname_to_dw2regnum ("rip"), -8);
+      cfi_add_insn (CFA_def_cfa, tc_x86_regname_to_dw2regnum ("rsp", NULL), 8);
+      cfi_add_insn (CFA_offset, tc_x86_regname_to_dw2regnum ("rip", NULL), -8);
     }
   else
     {
-      cfi_add_insn (CFA_def_cfa, tc_x86_regname_to_dw2regnum ("esp"), 4);
-      cfi_add_insn (CFA_offset, tc_x86_regname_to_dw2regnum ("eip"), -4);
+      cfi_add_insn (CFA_def_cfa, tc_x86_regname_to_dw2regnum ("esp", NULL), 4);
+      cfi_add_insn (CFA_offset, tc_x86_regname_to_dw2regnum ("eip", NULL), -4);
     }
 }
Index: config/tc-i386.h
===================================================================
RCS file: /cvs/src/src/gas/config/tc-i386.h,v
retrieving revision 1.40
diff -u -p -r1.40 tc-i386.h
--- config/tc-i386.h	20 May 2003 07:58:07 -0000	1.40
+++ config/tc-i386.h	21 May 2003 16:32:38 -0000
@@ -553,7 +553,8 @@ extern void sco_id PARAMS ((void));
 extern void tc_x86_cfi_init PARAMS ((void));
 
 #define tc_regname_to_dw2regnum tc_x86_regname_to_dw2regnum
-extern unsigned long tc_x86_regname_to_dw2regnum PARAMS ((const char *regname));
+extern unsigned long tc_x86_regname_to_dw2regnum PARAMS ((char *regname, 
+							  int *size));
 
 #define tc_cfi_frame_initial_instructions tc_x86_frame_initial_instructions
 extern void tc_x86_frame_initial_instructions PARAMS ((void));
Index: testsuite/gas/cfi/cfi-x86_64.d
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/cfi/cfi-x86_64.d,v
retrieving revision 1.2
diff -u -p -r1.2 cfi-x86_64.d
--- testsuite/gas/cfi/cfi-x86_64.d	20 May 2003 14:31:44 -0000	1.2
+++ testsuite/gas/cfi/cfi-x86_64.d	21 May 2003 16:32:38 -0000
@@ -41,7 +41,7 @@ The section .eh_frame contains:
 
 00000060 0000001c 00000064 FDE cie=00000000 pc=00000000..00000013
   DW_CFA_advance_loc: 3 to 00000003
-  DW_CFA_def_cfa_reg: r12
+  DW_CFA_def_cfa_reg: r8
   DW_CFA_advance_loc: 15 to 00000012
   DW_CFA_def_cfa_reg: r7
   DW_CFA_nop
Index: testsuite/gas/cfi/cfi-x86_64.s
===================================================================
RCS file: /cvs/src/src/gas/testsuite/gas/cfi/cfi-x86_64.s,v
retrieving revision 1.1
diff -u -p -r1.1 cfi-x86_64.s
--- testsuite/gas/cfi/cfi-x86_64.s	20 May 2003 08:01:19 -0000	1.1
+++ testsuite/gas/cfi/cfi-x86_64.s	21 May 2003 16:32:38 -0000
@@ -35,9 +35,9 @@ func_prologue:
 	#; each instruction.
 	pushq	%rbp
 	.cfi_def_cfa_offset	16
-	.cfi_offset		rbp,-16
+	.cfi_offset		%rbp, -16
 	movq	%rsp, %rbp
-	.cfi_def_cfa_register	rbp
+	.cfi_def_cfa_register	%rbp
 
 	#; function body
 	call	func_locvars
@@ -46,7 +46,7 @@ func_prologue:
 	#; epilogue with valid CFI
 	#; (we're better than gcc :-)
 	leaveq
-	.cfi_def_cfa		rsp,8
+	.cfi_def_cfa		%rsp, 8
 	ret
 	.cfi_endproc
 
@@ -59,21 +59,21 @@ func_prologue:
 func_otherreg:
 	.cfi_startproc
 
-	#; save frame pointer to r12
-	movq	%rsp,%r12
-	.cfi_def_cfa_register	r12
+	#; save frame pointer to r8
+	movq	%rsp,%r8
+	.cfi_def_cfa_register	r8
 
 	#; alocate space for local vars
 	#;  (no .cfi_{def,adjust}_cfa_offset here,
-	#;   because CFA is computed from r12!)
+	#;   because CFA is computed from r8!)
 	sub	$100,%rsp
 
 	#; function body
 	call	func_prologue
 	addl	$2, %eax
 	
-	#; restore frame pointer from r12
-	movq	%r12,%rsp
+	#; restore frame pointer from r8
+	movq	%r8,%rsp
 	.cfi_def_cfa_register	rsp
 	ret
 	.cfi_endproc