* config/sparc/nm-linux.h: Include config/nm-linux.h.

[deliverable/binutils-gdb.git] / gdb / rs6000-tdep.c

diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 5b6dcad08481b8229a1f95cc1717a2d2abffd049..c3cd31b75e49dc5d4dd4639d8691eb3844755c39 100644 (file)
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -1,5 +1,5 @@
 /* Target-dependent code for GDB, the GNU debugger.
-   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
+   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -305,37 +305,43 @@ rs6000_software_single_step (signal, insert_breakpoints_p)
 #define GET_SRC_REG(x) (((x) >> 21) & 0x1f)
 
 CORE_ADDR
-skip_prologue (pc, fdata)
-     CORE_ADDR pc;
-     struct rs6000_framedata *fdata;
+skip_prologue (CORE_ADDR pc, struct rs6000_framedata *fdata)
 {
   CORE_ADDR orig_pc = pc;
+  CORE_ADDR last_prologue_pc;
   char buf[4];
   unsigned long op;
   long offset = 0;
-  int lr_reg = 0;
-  int cr_reg = 0;
+  int lr_reg = -1;
+  int cr_reg = -1;
   int reg;
   int framep = 0;
   int minimal_toc_loaded = 0;
-  static struct rs6000_framedata zero_frame;
+  int prev_insn_was_prologue_insn = 1;
 
-  *fdata = zero_frame;
+  memset (fdata, 0, sizeof (struct rs6000_framedata));
   fdata->saved_gpr = -1;
   fdata->saved_fpr = -1;
   fdata->alloca_reg = -1;
   fdata->frameless = 1;
   fdata->nosavedpc = 1;
 
-  if (target_read_memory (pc, buf, 4))
-    return pc;                 /* Can't access it -- assume no prologue. */
-
-  /* Assume that subsequent fetches can fail with low probability.  */
   pc -= 4;
   for (;;)
     {
       pc += 4;
-      op = read_memory_integer (pc, 4);
+
+      /* Sometimes it isn't clear if an instruction is a prologue
+         instruction or not.  When we encounter one of these ambiguous
+        cases, we'll set prev_insn_was_prologue_insn to 0 (false).
+        Otherwise, we'll assume that it really is a prologue instruction. */
+      if (prev_insn_was_prologue_insn)
+       last_prologue_pc = pc;
+      prev_insn_was_prologue_insn = 1;
+
+      if (target_read_memory (pc, buf, 4))
+       break;
+      op = extract_signed_integer (buf, 4);
 
       if ((op & 0xfc1fffff) == 0x7c0802a6)
        {                       /* mflr Rx */
@@ -374,6 +380,16 @@ skip_prologue (pc, fdata)
            }
          continue;
 
+       }
+      else if ((op & 0xffff0000) == 0x60000000)
+        {
+                               /* nop */
+         /* Allow nops in the prologue, but do not consider them to
+            be part of the prologue unless followed by other prologue
+            instructions. */
+         prev_insn_was_prologue_insn = 0;
+         continue;
+
        }
       else if ((op & 0xffff0000) == 0x3c000000)
        {                       /* addis 0,0,NUM, used
@@ -391,7 +407,7 @@ skip_prologue (pc, fdata)
          continue;
 
        }
-      else if ((op & 0xffff0000) == lr_reg)
+      else if (lr_reg != -1 && (op & 0xffff0000) == lr_reg)
        {                       /* st Rx,NUM(r1) 
                                   where Rx == lr */
          fdata->lr_offset = SIGNED_SHORT (op) + offset;
@@ -400,7 +416,7 @@ skip_prologue (pc, fdata)
          continue;
 
        }
-      else if ((op & 0xffff0000) == cr_reg)
+      else if (cr_reg != -1 && (op & 0xffff0000) == cr_reg)
        {                       /* st Rx,NUM(r1) 
                                   where Rx == cr */
          fdata->cr_offset = SIGNED_SHORT (op) + offset;
@@ -564,7 +580,7 @@ skip_prologue (pc, fdata)
 #endif /* 0 */
 
   fdata->offset = -fdata->offset;
-  return pc;
+  return last_prologue_pc;
 }
 
 
@@ -1238,8 +1254,7 @@ skip_trampoline_code (pc)
 /* Determines whether the function FI has a frame on the stack or not.  */
 
 int
-frameless_function_invocation (fi)
-     struct frame_info *fi;
+rs6000_frameless_function_invocation (struct frame_info *fi)
 {
   CORE_ADDR func_start;
   struct rs6000_framedata fdata;
@@ -1273,8 +1288,7 @@ frameless_function_invocation (fi)
 /* Return the PC saved in a frame */
 
 unsigned long
-frame_saved_pc (fi)
-     struct frame_info *fi;
+rs6000_frame_saved_pc (struct frame_info *fi)
 {
   CORE_ADDR func_start;
   struct rs6000_framedata fdata;
@@ -1302,14 +1316,13 @@ frame_saved_pc (fi)
       if (fi->next->signal_handler_caller)
        return read_memory_integer (fi->next->frame + SIG_FRAME_LR_OFFSET, 4);
       else
-       return read_memory_integer (rs6000_frame_chain (fi) + DEFAULT_LR_SAVE,
-                                   4);
+       return read_memory_integer (FRAME_CHAIN (fi) + DEFAULT_LR_SAVE, 4);
     }
 
   if (fdata.lr_offset == 0)
     return read_register (LR_REGNUM);
 
-  return read_memory_integer (rs6000_frame_chain (fi) + fdata.lr_offset, 4);
+  return read_memory_integer (FRAME_CHAIN (fi) + fdata.lr_offset, 4);
 }
 
 /* If saved registers of frame FI are not known yet, read and cache them.
@@ -1480,7 +1493,7 @@ rs6000_frame_chain (thisframe)
     fp = read_memory_integer (thisframe->frame + SIG_FRAME_FP_OFFSET, 4);
   else if (thisframe->next != NULL
           && thisframe->next->signal_handler_caller
-          && frameless_function_invocation (thisframe))
+          && FRAMELESS_FUNCTION_INVOCATION (thisframe))
     /* A frameless function interrupted by a signal did not change the
        frame pointer.  */
     fp = FRAME_FP (thisframe);