Re: [Patch] fix for PR:1291

[Elena Zannoni <ezannoni@redhat.com>]

kewarken writes:
 > This patch addresses an issue with SH processors where gdb cannot
 > backtrace out of function with more than 256 bytes of local variables.
 > 
 > Code such as:
 > 
 > sub1()
 > {
 >         int buf[64];
 > }
 > 
 > sub2()
 > {
 >         int buf[65];
 > }
 > 
 > generates prologues such as:
 > 
 > sub1:
 > 	mov.l	r14,@-r15
 > 	add	#-128,r15
 > 	add	#-128,r15
 > 	mov	r15,r14
 > .L8:
 > 	mov.w	.L9,r7
 > 	add	r7,r14
 > 	mov	r14,r15
 > 	mov.l	@r15+,r14
 > 	rts
 > 	nop
 > 	.align 1
 > .L9:
 > 	.short	256
 > 
 > and
 > 
 > sub2:
 > 	mov.l	r14,@-r15
 > 	mov.w	.L11,r3
 > 	sub	r3,r15
 > 	mov	r15,r14
 > .L10:
 > 	mov.w	.L11,r7
 > 	add	r7,r14
 > 	mov	r14,r15
 > 	mov.l	@r15+,r14
 > 	rts
 > 	nop
 > 	.align 1
 > .L11:
 > 	.short	260
 > 
 > 
 > The second form is not recognized properly by the frame code in gdb.  In
 > the gcc 3 series, r1 is used instead of r3 so this patch expands on the
 > original patch attached to the PR.
 > 
 > Credit to inaba@src.ricoh.co.jp for his original find and patch and to
 > Colin Burgess for noting the differences between gcc 2 and 3.
 > 
 > ChangeLog:
 > 
 > 2003-09-16  Kris Warkentin  <kewarken@qnx.com>
 > 
 > 	* sh-tdep.c: Properly detect frame prologues for functions with
 > 	more than 256 bytes of local variables.

You should give credit to these folks in the changelog entry.

I wonder if this can be captured in a test case?  How does your change
interacts with Corinna's rewrite?

elena



 >Index: sh-tdep.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/sh-tdep.c,v
 > retrieving revision 1.136
 > diff -u -r1.136 sh-tdep.c
 > --- sh-tdep.c	21 Aug 2003 00:01:31 -0000	1.136
 > +++ sh-tdep.c	16 Sep 2003 18:35:39 -0000
 > @@ -622,13 +622,39 @@
 >     r15+imm-->r15 */
 >  #define IS_ADD_SP(x) 		(((x) & 0xff00) == 0x7f00)
 >  
 > -#define IS_MOV_R3(x) 		(((x) & 0xff00) == 0x1a00)
 > +/* MOV #imm,r3     11100011iiiiiiii
 > +   imm-->r3 */
 > +#define IS_MOV_R3(x) (((x) & 0xff00) == 0xe300)
 >  #define IS_SHLL_R3(x)		((x) == 0x4300)
 >  
 >  /* ADD r3,r15      0011111100111100
 >     r15+r3-->r15 */
 >  #define IS_ADD_R3SP(x)		((x) == 0x3f3c)
 >  
 > +/* MOV.W @(disp, pc), r1     10010001dddddddd
 > +   (disp * 2 + pc + 4)-->r1 */
 > +#define IS_MOVW_R1(x) (((x) & 0xff00) == 0x9100)
 > +
 > +/* MOV.L @(disp, pc), r1     11010001dddddddd
 > +   (disp * 4 + pc + 4)-->r1 */
 > +#define IS_MOVL_R1(x) (((x) & 0xff00) == 0xd100)
 > +
 > +/* SUB r1,r15      00111111100011000
 > +   r15-r1-->r15 */
 > +#define IS_SUB_R1SP(x) ((x) == 0x3f18)
 > +
 > +/* MOV.W @(disp, pc), r3     10010011dddddddd
 > +   (disp * 2 + pc + 4)-->r3 */
 > +#define IS_MOVW_R3(x) (((x) & 0xff00) == 0x9300)
 > +
 > +/* MOV.L @(disp, pc), r3     11010011dddddddd
 > +   (disp * 4 + pc + 4)-->r3 */
 > +#define IS_MOVL_R3(x) (((x) & 0xff00) == 0xd300)
 > +
 > +/* SUB r3,r15      00111111100111000
 > +   r15-r3-->r15 */
 > +#define IS_SUB_R3SP(x) ((x) == 0x3f38)
 > +
 >  /* FMOV.S FRm,@-Rn  Rn-4-->Rn, FRm-->(Rn)     1111nnnnmmmm1011
 >     FMOV DRm,@-Rn    Rn-8-->Rn, DRm-->(Rn)     1111nnnnmmm01011
 >     FMOV XDm,@-Rn    Rn-8-->Rn, XDm-->(Rn)     1111nnnnmmm11011 */
 > @@ -696,8 +722,11 @@
 >      {
 >        int w = read_memory_integer (here, 2);
 >        here += 2;
 > -      if (IS_FMOV (w) || IS_PUSH (w) || IS_STS (w) || IS_MOV_R3 (w)
 > -	  || IS_ADD_R3SP (w) || IS_ADD_SP (w) || IS_SHLL_R3 (w) 
 > +      if (IS_FMOV (w) || IS_PUSH (w) || IS_STS (w) 
 > +	  || IS_MOV_R3 (w)
 > +	  || IS_MOVW_R3 (w) || IS_MOVL_R3 (w) || IS_SUB_R3SP (w) || IS_ADD_R3SP (w) 
 > +	  || IS_MOVW_R1 (w) || IS_MOVL_R1 (w) || IS_SUB_R1SP (w) 
 > +	  || IS_ADD_SP (w) || IS_SHLL_R3 (w) 
 >  	  || IS_ARG_MOV (w) || IS_MOV_TO_R14 (w))
 >  	{
 >  	  start_pc = here;
 > @@ -1101,6 +1130,7 @@
 >    int pc;
 >    int opc;
 >    int insn;
 > +  int r1_val = 0;
 >    int r3_val = 0;
 >    char *dummy_regs = deprecated_generic_find_dummy_frame (get_frame_pc (fi),
 >  							  get_frame_base (fi));
 > @@ -1167,6 +1197,30 @@
 >  	{
 >  	  depth += -r3_val;
 >  	}
 > +      else if (IS_MOVW_R1 (insn))
 > +	{
 > +	  r1_val = read_memory_integer (pc + 4 + (insn & 0xff) * 2, 2);
 > +	}
 > +      else if (IS_MOVL_R1 (insn))
 > +	{
 > +	  r1_val = read_memory_integer (pc + 4 + (insn & 0xff) * 4, 4);
 > +	}
 > +      else if (IS_SUB_R1SP (insn))
 > +	{
 > +	  depth += r1_val;
 > +	}
 > +      else if (IS_MOVW_R3 (insn))
 > +	{
 > +	  r3_val = read_memory_integer (pc + 4 + (insn & 0xff) * 2, 2);
 > +	}
 > +      else if (IS_MOVL_R3 (insn))
 > +	{
 > +	  r3_val = read_memory_integer (pc + 4 + (insn & 0xff) * 4, 4);
 > +	}
 > +      else if (IS_SUB_R3SP (insn))
 > +	{
 > +	  depth += r3_val;
 > +	}
 >        else if (IS_ADD_SP (insn))
 >  	{
 >  	  depth -= ((insn & 0xff) ^ 0x80) - 0x80;
 > @@ -1642,6 +1696,7 @@
 >    int pc;
 >    int opc;
 >    int insn;
 > +  int r1_val = 0;
 >    int r3_val = 0;
 >    char *dummy_regs = deprecated_generic_find_dummy_frame (get_frame_pc (fi), get_frame_base (fi));
 >    struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); 
 > @@ -1707,6 +1762,30 @@
 >        else if (IS_ADD_R3SP (insn))
 >  	{
 >  	  depth += -r3_val;
 > +	}
 > +      else if (IS_MOVW_R1 (insn))
 > +	{
 > +	  r1_val = read_memory_integer (pc + 4 + (insn & 0xff) * 2, 2);
 > +	}
 > +      else if (IS_MOVL_R1 (insn))
 > +	{
 > +	  r1_val = read_memory_integer (pc + 4 + (insn & 0xff) * 4, 4);
 > +	}
 > +      else if (IS_SUB_R1SP (insn))
 > +	{
 > +	  depth += r1_val;
 > +	}
 > +      else if (IS_MOVW_R3 (insn))
 > +	{
 > +	  r3_val = read_memory_integer (pc + 4 + (insn & 0xff) * 2, 2);
 > +	}
 > +      else if (IS_MOVL_R3 (insn))
 > +	{
 > +	  r3_val = read_memory_integer (pc + 4 + (insn & 0xff) * 4, 4);
 > +	}
 > +      else if (IS_SUB_R3SP (insn))
 > +	{
 > +	  depth += r3_val;
 >  	}
 >        else if (IS_ADD_SP (insn))
 >  	{