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.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 82a3a0d..3a4fcef 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -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.

diff --git a/gdb/ax-general.c b/gdb/ax-general.c
index eb7a7ca..52fcfc8 100644 (file)
--- a/gdb/ax-general.c
+++ b/gdb/ax-general.c
@@ -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