* config/i386/tm-i386v4.h (I386V4_SIGTRAMP_SAVED_PC, IN_SIGTRAMP,

	FRAME_CHAIN, FRAMELESS_FUNCTION_INVOCATION, FRAME_SAVED_PC):
	Define to make backtracing through the various sigtramp handlers
	work.
	* i386-tdep.c (i386v4_sigtramp_saved_pc):  New routine to fetch
	the saved pc from ucontext on the stack for SVR4 signal handling.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 50503bfc3d3a738b44dfa15d4a5c7e16df6f2fb6..88f97497af55e297cb7b19b26236633607bdda68 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+Sun Feb 27 21:39:48 1994  Peter Schauer  (pes@regent.e-technik.tu-muenchen.de)
+
+       * config/i386/tm-i386v4.h (I386V4_SIGTRAMP_SAVED_PC, IN_SIGTRAMP,
+       FRAME_CHAIN, FRAMELESS_FUNCTION_INVOCATION, FRAME_SAVED_PC):
+       Define to make backtracing through the various sigtramp handlers
+       work.
+       * i386-tdep.c (i386v4_sigtramp_saved_pc):  New routine to fetch
+       the saved pc from ucontext on the stack for SVR4 signal handling.
+
 Fri Feb 25 09:41:11 1994  Jim Kingdon  (kingdon@deneb.cygnus.com)
 
        * remote.c, remote-mon.c, remote-utils.c, remote-utils.h,

diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index d6d20b09089cf245a532bf2b8d2e0ce2bfdd7b84..e6ee9ce0928d21b51aa4b3c8d63fcf7367508666 100644 (file)
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -1,5 +1,5 @@
 /* Intel 386 target-dependent stuff.
-   Copyright (C) 1988, 1989, 1991 Free Software Foundation, Inc.
+   Copyright (C) 1988, 1989, 1991, 1994 Free Software Foundation, Inc.
 
 This file is part of GDB.
 
@@ -22,6 +22,7 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #include "inferior.h"
 #include "gdbcore.h"
 #include "target.h"
+#include "symtab.h"
 
 static long
 i386_get_frame_setup PARAMS ((int));
@@ -115,42 +116,48 @@ codestream_read (buf, count)
 static void
 i386_follow_jump ()
 {
-  int long_delta;
-  short short_delta;
-  char byte_delta;
+  unsigned char buf[4];
+  long delta;
+
   int data16;
-  int pos;
-  
+  CORE_ADDR pos;
+
   pos = codestream_tell ();
-  
+
   data16 = 0;
   if (codestream_peek () == 0x66)
     {
       codestream_get ();
       data16 = 1;
     }
-  
+
   switch (codestream_get ())
     {
     case 0xe9:
       /* relative jump: if data16 == 0, disp32, else disp16 */
       if (data16)
        {
-         codestream_read ((unsigned char *)&short_delta, 2);
+         codestream_read (buf, 2);
+         delta = extract_signed_integer (buf, 2);
 
          /* include size of jmp inst (including the 0x66 prefix).  */
-         pos += short_delta + 4; 
+         pos += delta + 4; 
        }
       else
        {
-         codestream_read ((unsigned char *)&long_delta, 4);
-         pos += long_delta + 5;
+         codestream_read (buf, 4);
+         delta = extract_signed_integer (buf, 4);
+
+         pos += delta + 5;
        }
       break;
     case 0xeb:
       /* relative jump, disp8 (ignore data16) */
-      codestream_read ((unsigned char *)&byte_delta, 1);
-      pos += byte_delta + 2;
+      codestream_read (buf, 1);
+      /* Sign-extend it.  */
+      delta = extract_signed_integer (buf, 1);
+
+      pos += delta + 2;
       break;
     }
   codestream_seek (pos);
@@ -169,13 +176,13 @@ i386_get_frame_setup (pc)
      int pc;
 {
   unsigned char op;
-  
+
   codestream_seek (pc);
-  
+
   i386_follow_jump ();
-  
+
   op = codestream_get ();
-  
+
   if (op == 0x58)              /* popl %eax */
     {
       /*
@@ -202,11 +209,11 @@ i386_get_frame_setup (pc)
        pos += 3;
       else if (memcmp (buf, proto2, 4) == 0)
        pos += 4;
-      
+
       codestream_seek (pos);
       op = codestream_get (); /* update next opcode */
     }
-  
+
   if (op == 0x55)              /* pushl %ebp */
     {                  
       /* check for movl %esp, %ebp - can be written two ways */
@@ -441,6 +448,10 @@ i386_skip_prologue (pc)
 {
   unsigned char op;
   int i;
+  static unsigned char pic_pat[6] = { 0xe8, 0, 0, 0, 0, /* call   0x0 */
+                                     0x5b,             /* popl   %ebx */
+                                   };
+  CORE_ADDR pos;
   
   if (i386_get_frame_setup (pc) < 0)
     return (pc);
@@ -458,6 +469,54 @@ i386_skip_prologue (pc)
        break;
       codestream_get ();
     }
+
+  /* The native cc on SVR4 in -K PIC mode inserts the following code to get
+     the address of the global offset table (GOT) into register %ebx.
+      call     0x0
+      popl     %ebx
+      movl     %ebx,x(%ebp)    (optional)
+      addl     y,%ebx
+     This code is with the rest of the prologue (at the end of the
+     function), so we have to skip it to get to the first real
+     instruction at the start of the function.  */
+     
+  pos = codestream_tell ();
+  for (i = 0; i < 6; i++)
+    {
+      op = codestream_get ();
+      if (pic_pat [i] != op)
+       break;
+    }
+  if (i == 6)
+    {
+      unsigned char buf[4];
+      long delta = 6;
+
+      op = codestream_get ();
+      if (op == 0x89)                  /* movl %ebx, x(%ebp) */
+       {
+         op = codestream_get ();
+         if (op == 0x5d)               /* one byte offset from %ebp */
+           {
+             delta += 3;
+             codestream_read (buf, 1);
+           }
+         else if (op == 0x9d)          /* four byte offset from %ebp */
+           {
+             delta += 6;
+             codestream_read (buf, 4);
+           }
+         else                          /* unexpected instruction */
+             delta = -1;
+          op = codestream_get ();
+       }
+                                       /* addl y,%ebx */
+      if (delta > 0 && op == 0x81 && codestream_get () == 0xc3) 
+       {
+           pos += delta + 6;
+       }
+    }
+  codestream_seek (pos);
   
   i386_follow_jump ();
   
@@ -565,21 +624,7 @@ i386_extract_return_value(type, regbuf, valbuf)
       ieee_extended_to_double (&ext_format_i387,
                               &regbuf[REGISTER_BYTE(FP0_REGNUM)],
                               &d);
-      switch (TYPE_LENGTH(type))
-       {
-       case 4:                 /* float */
-         {
-           float f = (float) d;
-           memcpy (valbuf, &f, 4); 
-           break;
-         }
-       case 8:                 /* double */
-         memcpy (valbuf, &d, 8);
-         break;
-       default:
-         error("Unknown floating point size");
-         break;
-       }
+      store_floating (valbuf, TYPE_LENGTH (type), d);
     }
   else
     { 
@@ -587,3 +632,32 @@ i386_extract_return_value(type, regbuf, valbuf)
     }
 }
 #endif /* I386_AIX_TARGET */
+
+#ifdef I386V4_SIGTRAMP_SAVED_PC
+/* Get saved user PC for sigtramp from the pushed ucontext on the stack
+   for all three variants of SVR4 sigtramps.  */
+
+CORE_ADDR
+i386v4_sigtramp_saved_pc (frame)
+     FRAME frame;
+{
+  CORE_ADDR saved_pc_offset = 4;
+  char *name = NULL;
+
+  find_pc_partial_function (frame->pc, &name,
+                           (CORE_ADDR *)NULL,(CORE_ADDR *)NULL);
+  if (name)
+    {
+      if (STREQ (name, "_sigreturn"))
+       saved_pc_offset = 132 + 14 * 4;
+      if (STREQ (name, "_sigacthandler"))
+       saved_pc_offset = 80 + 14 * 4;
+      if (STREQ (name, "sigvechandler"))
+       saved_pc_offset = 120 + 14 * 4;
+    }
+
+  if (frame->next)
+    return read_memory_integer (frame->next->frame + saved_pc_offset, 4);
+  return read_memory_integer (read_register (SP_REGNUM) + saved_pc_offset, 4);
+}
+#endif /* I386V4_SIGTRAMP_SAVED_PC */