* arm-tdep.c (arm_scan_prologue): Don't require "mov ip, sp"

	to be the first instruction in the prologue.  Also, revise
	the way the frame offset is computed for frameless functions.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 634024a..34cf3fd 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -8,6 +8,10 @@
        is no longer needed now that the frame info is being properly
        initialized.
 
+       * arm-tdep.c (arm_scan_prologue): Don't require "mov ip, sp"
+       to be the first instruction in the prologue.  Also, revise
+       the way the frame offset is computed for frameless functions.
+
 2001-12-20  Michael Snyder  <msnyder@redhat.com>
 
        * maint.c (maintenance_info_sections): Pass string argument to

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 4e88dd6..b78a53a 100644 (file)
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -812,98 +812,104 @@ arm_scan_prologue (struct frame_info *fi)
      traceback.
 
      In the APCS, the prologue should start with  "mov ip, sp" so
-     if we don't see this as the first insn, we will stop.  */
+     if we don't see this as the first insn, we will stop.  [Note:
+     This doesn't seem to be true any longer, so it's now an optional
+     part of the prologue.  - Kevin Buettner, 2001-11-20]  */
 
   sp_offset = fp_offset = 0;
 
   if (read_memory_unsigned_integer (prologue_start, 4)
       == 0xe1a0c00d)           /* mov ip, sp */
+    current_pc = prologue_start + 4;
+  else
+    current_pc = prologue_start;
+
+  for (; current_pc < prologue_end; current_pc += 4)
     {
-      for (current_pc = prologue_start + 4; current_pc < prologue_end;
-          current_pc += 4)
+      unsigned int insn = read_memory_unsigned_integer (current_pc, 4);
+
+      if ((insn & 0xffff0000) == 0xe92d0000)
+       /* stmfd sp!, {..., fp, ip, lr, pc}
+          or
+          stmfd sp!, {a1, a2, a3, a4}  */
        {
-         unsigned int insn = read_memory_unsigned_integer (current_pc, 4);
+         int mask = insn & 0xffff;
 
-         if ((insn & 0xffff0000) == 0xe92d0000)
-           /* stmfd sp!, {..., fp, ip, lr, pc}
-              or
-              stmfd sp!, {a1, a2, a3, a4}  */
-           {
-             int mask = insn & 0xffff;
+         /* Calculate offsets of saved registers. */
+         for (regno = PC_REGNUM; regno >= 0; regno--)
+           if (mask & (1 << regno))
+             {
+               sp_offset -= 4;
+               fi->fsr.regs[regno] = sp_offset;
+             }
+       }
+      else if ((insn & 0xfffff000) == 0xe24cb000)      /* sub fp, ip #n */
+       {
+         unsigned imm = insn & 0xff;   /* immediate value */
+         unsigned rot = (insn & 0xf00) >> 7;   /* rotate amount */
+         imm = (imm >> rot) | (imm << (32 - rot));
+         fp_offset = -imm;
+         fi->framereg = FP_REGNUM;
+       }
+      else if ((insn & 0xfffff000) == 0xe24dd000)      /* sub sp, sp #n */
+       {
+         unsigned imm = insn & 0xff;   /* immediate value */
+         unsigned rot = (insn & 0xf00) >> 7;   /* rotate amount */
+         imm = (imm >> rot) | (imm << (32 - rot));
+         sp_offset -= imm;
+       }
+      else if ((insn & 0xffff7fff) == 0xed6d0103)      /* stfe f?, [sp, -#c]! */
+       {
+         sp_offset -= 12;
+         regno = F0_REGNUM + ((insn >> 12) & 0x07);
+         fi->fsr.regs[regno] = sp_offset;
+       }
+      else if ((insn & 0xffbf0fff) == 0xec2d0200)      /* sfmfd f0, 4, [sp!] */
+       {
+         int n_saved_fp_regs;
+         unsigned int fp_start_reg, fp_bound_reg;
 
-             /* Calculate offsets of saved registers. */
-             for (regno = PC_REGNUM; regno >= 0; regno--)
-               if (mask & (1 << regno))
-                 {
-                   sp_offset -= 4;
-                   fi->fsr.regs[regno] = sp_offset;
-                 }
-           }
-         else if ((insn & 0xfffff000) == 0xe24cb000)   /* sub fp, ip #n */
+         if ((insn & 0x800) == 0x800)  /* N0 is set */
            {
-             unsigned imm = insn & 0xff;       /* immediate value */
-             unsigned rot = (insn & 0xf00) >> 7;       /* rotate amount */
-             imm = (imm >> rot) | (imm << (32 - rot));
-             fp_offset = -imm;
-             fi->framereg = FP_REGNUM;
+             if ((insn & 0x40000) == 0x40000)  /* N1 is set */
+               n_saved_fp_regs = 3;
+             else
+               n_saved_fp_regs = 1;
            }
-         else if ((insn & 0xfffff000) == 0xe24dd000)   /* sub sp, sp #n */
+         else
            {
-             unsigned imm = insn & 0xff;       /* immediate value */
-             unsigned rot = (insn & 0xf00) >> 7;       /* rotate amount */
-             imm = (imm >> rot) | (imm << (32 - rot));
-             sp_offset -= imm;
+             if ((insn & 0x40000) == 0x40000)  /* N1 is set */
+               n_saved_fp_regs = 2;
+             else
+               n_saved_fp_regs = 4;
            }
-         else if ((insn & 0xffff7fff) == 0xed6d0103)   /* stfe f?, [sp, -#c]! */
+
+         fp_start_reg = F0_REGNUM + ((insn >> 12) & 0x7);
+         fp_bound_reg = fp_start_reg + n_saved_fp_regs;
+         for (; fp_start_reg < fp_bound_reg; fp_start_reg++)
            {
              sp_offset -= 12;
-             regno = F0_REGNUM + ((insn >> 12) & 0x07);
-             fi->fsr.regs[regno] = sp_offset;
-           }
-         else if ((insn & 0xffbf0fff) == 0xec2d0200)   /* sfmfd f0, 4, [sp!] */
-           {
-             int n_saved_fp_regs;
-             unsigned int fp_start_reg, fp_bound_reg;
-
-             if ((insn & 0x800) == 0x800)      /* N0 is set */
-               {
-                 if ((insn & 0x40000) == 0x40000)      /* N1 is set */
-                   n_saved_fp_regs = 3;
-                 else
-                   n_saved_fp_regs = 1;
-               }
-             else
-               {
-                 if ((insn & 0x40000) == 0x40000)      /* N1 is set */
-                   n_saved_fp_regs = 2;
-                 else
-                   n_saved_fp_regs = 4;
-               }
-
-             fp_start_reg = F0_REGNUM + ((insn >> 12) & 0x7);
-             fp_bound_reg = fp_start_reg + n_saved_fp_regs;
-             for (; fp_start_reg < fp_bound_reg; fp_start_reg++)
-               {
-                 sp_offset -= 12;
-                 fi->fsr.regs[fp_start_reg++] = sp_offset;
-               }
+             fi->fsr.regs[fp_start_reg++] = sp_offset;
            }
-         else if ((insn & 0xf0000000) != 0xe0000000)
-           break;      /* Condition not true, exit early */
-         else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
-           break;      /* Don't scan past a block load */
-         else
-           /* The optimizer might shove anything into the prologue,
-              so we just skip what we don't recognize. */
-           continue;
        }
+      else if ((insn & 0xf0000000) != 0xe0000000)
+       break;  /* Condition not true, exit early */
+      else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
+       break;  /* Don't scan past a block load */
+      else
+       /* The optimizer might shove anything into the prologue,
+          so we just skip what we don't recognize. */
+       continue;
     }
 
   /* The frame size is just the negative of the offset (from the original SP)
      of the last thing thing we pushed on the stack.  The frame offset is
      [new FP] - [new SP].  */
   fi->framesize = -sp_offset;
-  fi->frameoffset = fp_offset - sp_offset;
+  if (fi->framereg == FP_REGNUM)
+    fi->frameoffset = fp_offset - sp_offset;
+  else
+    fi->frameoffset = 0;
 
   save_prologue_cache (fi);
 }