6069 libdisasm: instrlen arch op should have a sane default
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Dan McDonald <danmcd@omniti.com>
6068 libdisasm: previnstr arch op should have a sane default
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Dan McDonald <danmcd@omniti.com>
6067 libdisasm: use C99 designated initializers for arch ops
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Dan McDonald <danmcd@omniti.com>

*** 170,230 ****
  dis_i386_min_instrlen(dis_handle_t *dhp)
  {
          return (1);
  }
  
- /*
-  * Return the previous instruction.  On x86, we have no choice except to
-  * disassemble everything from the start of the symbol, and stop when we have
-  * reached our instruction address.  If we're not in the middle of a known
-  * symbol, then we return the same address to indicate failure.
-  */
- static uint64_t
- dis_i386_previnstr(dis_handle_t *dhp, uint64_t pc, int n)
- {
-         uint64_t *hist, addr, start;
-         int cur, nseen;
-         uint64_t res = pc;
- 
-         if (n <= 0)
-                 return (pc);
- 
-         if (dhp->dh_lookup(dhp->dh_data, pc, NULL, 0, &start, NULL) != 0 ||
-             start == pc)
-                 return (res);
- 
-         hist = dis_zalloc(sizeof (uint64_t) * n);
- 
-         for (cur = 0, nseen = 0, addr = start; addr < pc; addr = dhp->dh_addr) {
-                 hist[cur] = addr;
-                 cur = (cur + 1) % n;
-                 nseen++;
- 
-                 /* if we cannot make forward progress, give up */
-                 if (dis_disassemble(dhp, addr, NULL, 0) != 0)
-                         goto done;
-         }
- 
-         if (addr != pc) {
-                 /*
-                  * We scanned past %pc, but didn't find an instruction that
-                  * started at %pc.  This means that either the caller specified
-                  * an invalid address, or we ran into something other than code
-                  * during our scan.  Virtually any combination of bytes can be
-                  * construed as a valid Intel instruction, so any non-code bytes
-                  * we encounter will have thrown off the scan.
-                  */
-                 goto done;
-         }
- 
-         res = hist[(cur + n - MIN(n, nseen)) % n];
- 
- done:
-         dis_free(hist, sizeof (uint64_t) * n);
-         return (res);
- }
- 
  static int
  dis_i386_supports_flags(int flags)
  {
          int archflags = flags & DIS_ARCH_MASK;
  
--- 170,179 ----
*** 233,256 ****
                  return (1);
  
          return (0);
  }
  
- static int
- dis_i386_instrlen(dis_handle_t *dhp, uint64_t pc)
- {
-         if (dis_disassemble(dhp, pc, NULL, 0) != 0)
-                 return (-1);
- 
-         return (dhp->dh_addr - pc);
- }
- 
  dis_arch_t dis_arch_i386 = {
!         dis_i386_supports_flags,
!         dis_i386_handle_attach,
!         dis_i386_handle_detach,
!         dis_i386_disassemble,
!         dis_i386_previnstr,
!         dis_i386_min_instrlen,
!         dis_i386_max_instrlen,
!         dis_i386_instrlen,
  };
--- 182,194 ----
                  return (1);
  
          return (0);
  }
  
  dis_arch_t dis_arch_i386 = {
!         .da_supports_flags      = dis_i386_supports_flags,
!         .da_handle_attach       = dis_i386_handle_attach,
!         .da_handle_detach       = dis_i386_handle_detach,
!         .da_disassemble         = dis_i386_disassemble,
!         .da_min_instrlen        = dis_i386_min_instrlen,
!         .da_max_instrlen        = dis_i386_max_instrlen,
  };