s-mastop-irix.adb (Pop_Frame): Revert shorcuts avoiding calls to exc_unwind...

2005-06-14  Olivier Hainque  <hainque@adacore.com>
	    Eric Botcazou  <ebotcazou@adacore.com>

	* s-mastop-irix.adb (Pop_Frame): Revert shorcuts avoiding calls to
	exc_unwind, now that we are generating proper .debug_frame output for
	that target.

	* tracebak.c: Remove the mips-irix section, as we are now using the
	s-mastop based unwinder again.
	Under SPARC/Solaris, take into account the stack bias to compute the
	frame offset.  The stack bias is 0 for the V8 ABI and 2047 for the V9
	ABI.

From-SVN: r101012

gcc/ada/s-mastop-irix.adb

@@ -7,7 +7,7 @@
 --                                 B o d y                                  --
 --                         (Version for IRIX/MIPS)                          --
 --                                                                          --
---          Copyright (C) 1999-2004 Free Software Foundation, Inc.          --
+--          Copyright (C) 1999-2005 Free Software Foundation, Inc.          --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -295,21 +295,7 @@ package body System.Machine_State_Operations is
       procedure Exc_Unwind (Scp : Sigcontext_Ptr; Fde : Long_Integer := 0);
       pragma Import (C, Exc_Unwind, "exc_unwind");
 
-      --  ??? Calling exc_unwind in the current setup does not work and
-      --  triggers the emission of system warning messages. Why it does
-      --  not work remains to be investigated. Part of the problem is
-      --  probably a section naming issue (e.g. .eh_frame/.debug_frame).
-
-      --  Instead of letting the call take place for nothing and emit
-      --  messages we don't expect, we just arrange things to pretend it
-      --  occurred and failed.
-
-      --  ??? Until this is fixed, we shall document that the backtrace
-      --  computation facility does not work, and we inhibit the pragma below
-      --  because we arrange for the call not to be emitted and the linker
-      --  complains when a library is linked in but resolves nothing.
-
-      --  pragma Linker_Options ("-lexc");
+      pragma Linker_Options ("-lexc");
 
    begin
       --  exc_unwind is apparently not thread-safe under IRIX, so protect it
@@ -319,11 +305,7 @@ package body System.Machine_State_Operations is
 
       Lock_Task.all;
 
-      if False then
-         Exc_Unwind (Scp);
-      else
-         Scp.SC_PC := 0;
-      end if;
+      Exc_Unwind (Scp);
 
       Unlock_Task.all;
 

gcc/ada/tracebak.c

@@ -242,7 +242,7 @@ struct layout
 
 #define BASE_SKIP 1
 
-/*-------------------------- Sparc Solaris -----------------------------*/
+/*-------------------------- SPARC Solaris -----------------------------*/
 
 #elif defined (sun) && defined (sparc)
 
@@ -257,8 +257,14 @@ struct layout
   void *return_address;
 };
 
+#ifdef __arch64__
+#define STACK_BIAS 2047 /* V9 ABI */
+#else
+#define STACK_BIAS 0    /* V8 ABI */
+#endif
+
 #define FRAME_LEVEL 0
-#define FRAME_OFFSET (14 * (sizeof (void*)))
+#define FRAME_OFFSET (14 * sizeof (void*) + STACK_BIAS)
 #define PC_ADJUST 0
 #define STOP_FRAME(CURRENT, TOP_STACK) \
   ((CURRENT)->return_address == 0|| (CURRENT)->next == 0 \
@@ -324,12 +330,22 @@ struct layout
         || ((*((ptr) - 1) & 0xff) == 0xff) \
         || (((*(ptr) & 0xd0ff) == 0xd0ff))))
 
-/*------------------------------- mips-irix -------------------------------*/
+/*----------------------------- x86_64 ---------------------------------*/
 
-#elif defined (__mips) && defined (__sgi)
+#elif defined (__x86_64__)
 
 #define USE_GCC_UNWINDER
-#define PC_ADJUST -8
+/* The generic unwinder is not used for this target because it is based
+   on frame layout assumptions that are not reliable on this target (the
+   rbp register is very likely used for something else than storing the
+   frame pointer in optimized code). Hence, we use the GCC unwinder
+   based on DWARF 2 call frame information, although it has the drawback
+   of not being able to unwind through frames compiled without DWARF 2
+   information.
+*/
+
+#define PC_ADJUST -2
+/* The minimum size of call instructions on this architecture is 2 bytes */
 
 #endif