2005-12-07 Jim Blandy <jimb@redhat.com>

* ax-general.c (ax_reqs): Check stack heights for backward jumps,
	too.  Correctly check height at target.  Doc fixes.
This commit is contained in:
Jim Blandy 2005-12-07 19:30:25 +00:00
parent f287603758
commit 3d269a592e
2 changed files with 22 additions and 15 deletions

View File

@ -1,3 +1,8 @@
2005-12-07 Jim Blandy <jimb@redhat.com>
* ax-general.c (ax_reqs): Check stack heights for backward jumps,
too. Correctly check height at target. Doc fixes.
2005-12-06 Michael Snyder <msnyder@redhat.com>
* cli/cli-decode.c (add_setshow_string_cmd): Indent.

View File

@ -388,15 +388,15 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
int reg_mask_len = 1;
unsigned char *reg_mask = xmalloc (reg_mask_len * sizeof (reg_mask[0]));
/* Jump target table. targets[i] is non-zero iff there is a jump to
offset i. */
/* Jump target table. targets[i] is non-zero iff we have found a
jump to offset i. */
char *targets = (char *) alloca (ax->len * sizeof (targets[0]));
/* Instruction boundary table. boundary[i] is non-zero iff an
instruction starts at offset i. */
/* Instruction boundary table. boundary[i] is non-zero iff our scan
has reached an instruction starting at offset i. */
char *boundary = (char *) alloca (ax->len * sizeof (boundary[0]));
/* Stack height record. iff either targets[i] or boundary[i] is
/* Stack height record. If either targets[i] or boundary[i] is
non-zero, heights[i] is the height the stack should have before
executing the bytecode at that point. */
int *heights = (int *) alloca (ax->len * sizeof (heights[0]));
@ -437,8 +437,9 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
return;
}
/* If this instruction is a jump target, does the current stack
height match the stack height at the jump source? */
/* If this instruction is a forward jump target, does the
current stack height match the stack height at the jump
source? */
if (targets[i] && (heights[i] != height))
{
reqs->flaw = agent_flaw_height_mismatch;
@ -472,21 +473,22 @@ ax_reqs (struct agent_expr *ax, struct agent_reqs *reqs)
xfree (reg_mask);
return;
}
/* Have we already found other jumps to the same location? */
else if (targets[target])
/* Do we have any information about what the stack height
should be at the target? */
if (targets[target] || boundary[target])
{
if (heights[i] != height)
if (heights[target] != height)
{
reqs->flaw = agent_flaw_height_mismatch;
xfree (reg_mask);
return;
}
}
else
{
targets[target] = 1;
heights[target] = height;
}
/* Record the target, along with the stack height we expect. */
targets[target] = 1;
heights[target] = height;
}
/* For unconditional jumps with a successor, check that the