* mdebugread.c (parse_procedure): Remove _sigtramp kludges for

alpha and irix. The _sigtramp case has to be handled properly
	in the tdep files if we have no ecoff debugging info.
	* alpha-tdep.c (alpha_frame_saved_pc, alpha_frame_chain),
	mips-tdep.c (mips_frame_saved_pc):  Handle signal handler frames
	without PC_REGNUM kludge.
	* mdebugread.c (fixup_sigtramp), mips-tdep.c (read_next_frame_reg):
	Clean up handling of mips sigtramp frames, improve comments.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+Mon Jan 31 09:40:33 1994  Peter Schauer  (pes@regent.e-technik.tu-muenchen.de)
+
+	* mdebugread.c (parse_procedure):  Remove _sigtramp kludges for
+	alpha and irix. The _sigtramp case has to be handled properly
+	in the tdep files if we have no ecoff debugging info.
+	* alpha-tdep.c (alpha_frame_saved_pc, alpha_frame_chain),
+	mips-tdep.c (mips_frame_saved_pc):  Handle signal handler frames
+	without PC_REGNUM kludge.
+	* mdebugread.c (fixup_sigtramp), mips-tdep.c (read_next_frame_reg):
+	Clean up handling of mips sigtramp frames, improve comments.
+
 Sat Jan 29 23:25:57 1994  Jeffrey A. Law  (law@snake.cs.utah.edu)
 
 	* paread.c (read_unwind_info): Fix typo.

gdb/alpha-tdep.c

@@ -1,5 +1,5 @@
 /* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger.
-   Copyright 1993 Free Software Foundation, Inc.
+   Copyright 1993, 1994 Free Software Foundation, Inc.
 
 This file is part of GDB.
 
@@ -165,7 +165,10 @@ alpha_frame_saved_pc(frame)
      FRAME frame;
 {
   alpha_extra_func_info_t proc_desc = frame->proc_desc;
-  int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM;
+  /* We have to get the saved pc from the sigcontext
+     if it is a signal handler frame.  */
+  int pcreg = frame->signal_handler_caller ? PC_REGNUM
+	      : (proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM);
 
   if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
       return read_memory_integer(frame->frame - 8, 8);
@@ -428,14 +431,20 @@ alpha_frame_chain(frame)
        we loop forever if we see a zero size frame.  */
     if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
 	&& PROC_FRAME_OFFSET (proc_desc) == 0
-	/* The alpha __sigtramp routine is frameless and has a frame size
-	   of zero. Luckily it is the only procedure which has PC_REGNUM
-	   as PROC_PC_REG.  */
-	&& PROC_PC_REG (proc_desc) != PC_REGNUM
 	/* The previous frame from a sigtramp frame might be frameless
 	   and have frame size zero.  */
 	&& !frame->signal_handler_caller)
+      {
+	/* The alpha __sigtramp routine is frameless and has a frame size
+	   of zero, but we are able to backtrace through it. */
+	char *name;
+	find_pc_partial_function (saved_pc, &name,
+				  (CORE_ADDR *)NULL, (CORE_ADDR *)NULL);
+	if (IN_SIGTRAMP (saved_pc, name))
+	  return frame->frame;
+	else
 	  return 0;
+      }
     else
       return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc))
 	     + PROC_FRAME_OFFSET(proc_desc);

gdb/mdebugread.c

@@ -1,6 +1,6 @@
 /* Read a symbol table in ECOFF format (Third-Eye).
-   Copyright 1986, 1987, 1989, 1990, 1991, 1992, 1993 Free Software
+   Copyright 1986, 1987, 1989, 1990, 1991, 1992, 1993, 1994
-   Foundation, Inc.
+   Free Software Foundation, Inc.
    Original version contributed by Alessandro Forin (af@cs.cmu.edu) at
    CMU.  Major work by Per Bothner, John Gilmore and Ian Lance Taylor
    at Cygnus Support.
@@ -1815,14 +1815,6 @@ parse_procedure (pr, search_symtab, first_off)
 	  e->pdr.regmask = 0x80000000;
 	  e->pdr.regoffset = -4;
 	}
-
-      /* Fake PC_REGNUM for alpha __sigtramp so that read_next_frame_reg
-	 will use the saved user pc from the sigcontext.  */
-      if (STREQ (sh_name, "__sigtramp"))
-	e->pdr.pcreg = PC_REGNUM;
-      /* Make the same patch for Irix.  */
-      if (STREQ (sh_name, "_sigtramp"))
-	e->pdr.pcreg = PC_REGNUM;
     }
 }
 
@@ -3669,15 +3661,21 @@ fixup_sigtramp ()
        xzalloc (sizeof (struct mips_extra_func_info)));
 
     e->numargs = 0;		/* the kernel thinks otherwise */
-    /* align_longword(sigcontext + SIGFRAME) */
+    e->pdr.frameoffset = 32;
-    e->pdr.frameoffset = 0x150;
     e->pdr.framereg = SP_REGNUM;
-    /* read_next_frame_reg provides the true pc at the time of signal */
+    /* Note that setting pcreg is no longer strictly necessary as
+       mips_frame_saved_pc is now aware of signal handler frames.  */
     e->pdr.pcreg = PC_REGNUM;
     e->pdr.regmask = -2;
-    e->pdr.regoffset = -(41 * sizeof (int));
+    /* Offset to saved r31, in the sigtramp case the saved registers
+       are above the frame in the sigcontext.
+       We have 4 alignment bytes, 12 bytes for onstack, mask and pc,
+       32 * 4 bytes for the general registers, 12 bytes for mdhi, mdlo, ownedfp
+       and 32 * 4 bytes for the floating point registers.  */
+    e->pdr.regoffset = 4 + 12 + 31 * 4;
     e->pdr.fregmask = -1;
-    e->pdr.fregoffset = -(7 * sizeof (int));
+    /* Offset to saved f30 (first saved *double* register).  */
+    e->pdr.fregoffset = 4 + 12 + 32 * 4 + 12 + 30 * 4;
     e->pdr.isym = (long) s;
     e->pdr.adr = sigtramp_address;
 

gdb/mips-tdep.c

@@ -1,5 +1,6 @@
 /* Target-dependent code for the MIPS architecture, for GDB, the GNU Debugger.
-   Copyright 1988, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+   Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994
+   Free Software Foundation, Inc.
    Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
    and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
 
@@ -76,19 +77,21 @@ read_next_frame_reg(fi, regno)
      int regno;
 {
   /* If it is the frame for sigtramp we have a complete sigcontext
-     immediately below the frame and we get the saved registers from there.
+     somewhere above the frame and we get the saved registers from there.
      If the stack layout for sigtramp changes we might have to change these
      constants and the companion fixup_sigtramp in mdebugread.c  */
 #ifndef SIGFRAME_BASE
-#define SIGFRAME_BASE		0x12c	/* sizeof(sigcontext) */
+/* To satisfy alignment restrictions the sigcontext is located 4 bytes
-#define SIGFRAME_PC_OFF		(-SIGFRAME_BASE + 2 * 4)
+   above the sigtramp frame.  */
-#define SIGFRAME_REGSAVE_OFF	(-SIGFRAME_BASE + 3 * 4)
+#define SIGFRAME_BASE		4
+#define SIGFRAME_PC_OFF		(SIGFRAME_BASE + 2 * 4)
+#define SIGFRAME_REGSAVE_OFF	(SIGFRAME_BASE + 3 * 4)
 #endif
 #ifndef SIGFRAME_REG_SIZE
 #define SIGFRAME_REG_SIZE	4
 #endif
   for (; fi; fi = fi->next)
-      if (in_sigtramp(fi->pc, 0)) {
+      if (fi->signal_handler_caller) {
 	  int offset;
 	  if (regno == PC_REGNUM) offset = SIGFRAME_PC_OFF;
 	  else if (regno < 32) offset = (SIGFRAME_REGSAVE_OFF
@@ -107,7 +110,10 @@ mips_frame_saved_pc(frame)
      FRAME frame;
 {
   mips_extra_func_info_t proc_desc = frame->proc_desc;
-  int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM;
+  /* We have to get the saved pc from the sigcontext
+     if it is a signal handler frame.  */
+  int pcreg = frame->signal_handler_caller ? PC_REGNUM
+	      : (proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM);
 
   if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc))
       return read_memory_integer(frame->frame - 4, 4);