1 files changed, 53 insertions, 113 deletions

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index fa296d5db94..8f268974aa5 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -10800,132 +10800,40 @@ create_TOC_reference (symbol)
 		 gen_rtx_SYMBOL_REF (Pmode, toc_label_name))));
 }
 
-/* __throw will restore its own return address to be the same as the
-   return address of the function that the throw is being made to.
-   This is unfortunate, because we want to check the original
-   return address to see if we need to restore the TOC.
-   So we have to squirrel it away here.  
-   This is used only in compiling __throw and __rethrow. 
+/* If _Unwind_* has been called from within the same module,
+   toc register is not guaranteed to be saved to 40(1) on function
+   entry.  Save it there in that case.  */
 
-   Most of this code should be removed by CSE.  */
-static rtx insn_after_throw;
-
-/* This does the saving...  */
 void
 rs6000_aix_emit_builtin_unwind_init ()
 {
   rtx mem;
   rtx stack_top = gen_reg_rtx (Pmode);
   rtx opcode_addr = gen_reg_rtx (Pmode);
-
-  insn_after_throw = gen_reg_rtx (SImode);
+  rtx opcode = gen_reg_rtx (SImode);
+  rtx tocompare = gen_reg_rtx (SImode);
+  rtx no_toc_save_needed = gen_label_rtx ();
 
   mem = gen_rtx_MEM (Pmode, hard_frame_pointer_rtx);
   emit_move_insn (stack_top, mem);
 
-  mem = gen_rtx_MEM (Pmode, 
-		     gen_rtx_PLUS (Pmode, stack_top, 
+  mem = gen_rtx_MEM (Pmode,
+		     gen_rtx_PLUS (Pmode, stack_top,
 				   GEN_INT (2 * GET_MODE_SIZE (Pmode))));
   emit_move_insn (opcode_addr, mem);
-  emit_move_insn (insn_after_throw, gen_rtx_MEM (SImode, opcode_addr));
-}
-
-/* Emit insns to _restore_ the TOC register, at runtime (specifically
-   in _eh.o).  Only used on AIX.
-
-   The idea is that on AIX, function calls look like this:
-	bl  somefunction-trampoline
-	lwz r2,20(sp)
-
-   and later,
-	somefunction-trampoline:
-	stw r2,20(sp)
-	 ... load function address in the count register ...
-	bctr
-   or like this, if the linker determines that this is not a cross-module call
-   and so the TOC need not be restored:
-	bl  somefunction
-	nop
-   or like this, if the compiler could determine that this is not a
-   cross-module call:
-	bl  somefunction
-   now, the tricky bit here is that register 2 is saved and restored
-   by the _linker_, so we can't readily generate debugging information
-   for it.  So we need to go back up the call chain looking at the
-   insns at return addresses to see which calls saved the TOC register
-   and so see where it gets restored from.
-
-   Oh, and all this gets done in RTL inside the eh_epilogue pattern,
-   just before the actual epilogue.
-
-   On the bright side, this incurs no space or time overhead unless an
-   exception is thrown, except for the extra code in libgcc.a.  
-
-   The parameter STACKSIZE is a register containing (at runtime)
-   the amount to be popped off the stack in addition to the stack frame
-   of this routine (which will be __throw or __rethrow, and so is
-   guaranteed to have a stack frame).  */
-
-void
-rs6000_emit_eh_toc_restore (stacksize)
-     rtx stacksize;
-{
-  rtx top_of_stack;
-  rtx bottom_of_stack = gen_reg_rtx (Pmode);
-  rtx tocompare = gen_reg_rtx (SImode);
-  rtx opcode = gen_reg_rtx (SImode);
-  rtx opcode_addr = gen_reg_rtx (Pmode);
-  rtx mem;
-  rtx loop_start = gen_label_rtx ();
-  rtx no_toc_restore_needed = gen_label_rtx ();
-  rtx loop_exit = gen_label_rtx ();
-  
-  mem = gen_rtx_MEM (Pmode, hard_frame_pointer_rtx);
-  set_mem_alias_set (mem, rs6000_sr_alias_set);
-  emit_move_insn (bottom_of_stack, mem);
-
-  top_of_stack = expand_binop (Pmode, add_optab, 
-			       bottom_of_stack, stacksize,
-			       NULL_RTX, 1, OPTAB_WIDEN);
-
-  emit_move_insn (tocompare, gen_int_mode (TARGET_32BIT ? 0x80410014 
+  emit_move_insn (opcode, gen_rtx_MEM (SImode, opcode_addr));
+  emit_move_insn (tocompare, gen_int_mode (TARGET_32BIT ? 0x80410014
 					   : 0xE8410028, SImode));
 
-  if (insn_after_throw == NULL_RTX)
-    abort ();
-  emit_move_insn (opcode, insn_after_throw);
-  
-  emit_note (NOTE_INSN_LOOP_BEG);
-  emit_label (loop_start);
-  
-  do_compare_rtx_and_jump (opcode, tocompare, NE, 1,
+  do_compare_rtx_and_jump (opcode, tocompare, EQ, 1,
 			   SImode, NULL_RTX, NULL_RTX,
-			   no_toc_restore_needed);
-  
-  mem = gen_rtx_MEM (Pmode, 
-		     gen_rtx_PLUS (Pmode, bottom_of_stack, 
-				   GEN_INT (5 * GET_MODE_SIZE (Pmode))));
-  emit_move_insn (gen_rtx_REG (Pmode, 2), mem);
-
-  emit_label (no_toc_restore_needed);
-  do_compare_rtx_and_jump (top_of_stack, bottom_of_stack, EQ, 1,
-			   Pmode, NULL_RTX, NULL_RTX,
-			   loop_exit);
-
-  mem = gen_rtx_MEM (Pmode, bottom_of_stack);
-  set_mem_alias_set (mem, rs6000_sr_alias_set);
-  emit_move_insn (bottom_of_stack, mem);
-  
-  mem = gen_rtx_MEM (Pmode, 
-		     gen_rtx_PLUS (Pmode, bottom_of_stack, 
-				   GEN_INT (2 * GET_MODE_SIZE (Pmode))));
-  emit_move_insn (opcode_addr, mem);
-  emit_move_insn (opcode, gen_rtx_MEM (SImode, opcode_addr));
+			   no_toc_save_needed);
 
-  emit_note (NOTE_INSN_LOOP_CONT);
-  emit_jump (loop_start);
-  emit_note (NOTE_INSN_LOOP_END);
-  emit_label (loop_exit);
+  mem = gen_rtx_MEM (Pmode,
+		     gen_rtx_PLUS (Pmode, stack_top,
+				   GEN_INT (5 * GET_MODE_SIZE (Pmode))));
+  emit_move_insn (mem, gen_rtx_REG (Pmode, 2));
+  emit_label (no_toc_save_needed);
 }
 
 /* This ties together stack memory (MEM with an alias set of
@@ -11347,7 +11255,8 @@ rs6000_emit_prologue ()
 			|| FP_SAVE_INLINE (info->first_fp_reg_save));
 
   /* For V.4, update stack before we do any saving and set back pointer.  */
-  if (info->push_p && DEFAULT_ABI == ABI_V4)
+  if (info->push_p
+      && (DEFAULT_ABI == ABI_V4 || current_function_calls_eh_return))
     {
       if (info->total_size < 32767)
 	sp_offset = info->total_size;
@@ -11575,6 +11484,23 @@ rs6000_emit_prologue ()
     {
       unsigned int i, regno;
 
+      /* In AIX ABI we need to pretend we save r2 here.  */
+      if (TARGET_AIX)
+	{
+	  rtx addr, reg, mem;
+
+	  reg = gen_rtx_REG (reg_mode, 2);
+	  addr = gen_rtx_PLUS (Pmode, frame_reg_rtx,
+			       GEN_INT (sp_offset + 5 * reg_size));
+	  mem = gen_rtx_MEM (reg_mode, addr);
+	  set_mem_alias_set (mem, rs6000_sr_alias_set);
+
+	  insn = emit_move_insn (mem, reg);
+	  rs6000_frame_related (insn, frame_ptr_rtx, info->total_size, 
+				NULL_RTX, NULL_RTX);
+	  PATTERN (insn) = gen_blockage ();
+	}
+
       for (i = 0; ; ++i)
 	{
 	  regno = EH_RETURN_DATA_REGNO (i);
@@ -11633,7 +11559,8 @@ rs6000_emit_prologue ()
 
   /* Update stack and set back pointer unless this is V.4, 
      for which it was done previously.  */
-  if (info->push_p && DEFAULT_ABI != ABI_V4)
+  if (info->push_p
+      && !(DEFAULT_ABI == ABI_V4 || current_function_calls_eh_return))
     rs6000_emit_allocate_stack (info->total_size, FALSE);
 
   /* Set frame pointer, if needed.  */
@@ -11812,7 +11739,8 @@ rs6000_emit_epilogue (sibcall)
     }
   else if (info->push_p)
     {
-      if (DEFAULT_ABI == ABI_V4)
+      if (DEFAULT_ABI == ABI_V4
+	  || current_function_calls_eh_return)
 	sp_offset = info->total_size;
       else
 	{
@@ -11897,6 +11825,17 @@ rs6000_emit_epilogue (sibcall)
     {
       unsigned int i, regno;
 
+      if (TARGET_AIX)
+	{
+	  rtx addr = gen_rtx_PLUS (Pmode, frame_reg_rtx,
+				   GEN_INT (sp_offset + 5 * reg_size));
+	  rtx mem = gen_rtx_MEM (reg_mode, addr);
+
+	  set_mem_alias_set (mem, rs6000_sr_alias_set);
+
+	  emit_move_insn (gen_rtx_REG (reg_mode, 2), mem);
+	}
+
       for (i = 0; ; ++i)
 	{
 	  rtx mem;
@@ -12048,7 +11987,8 @@ rs6000_emit_epilogue (sibcall)
      (which may not have any obvious dependency on the stack).  This
      doesn't hurt performance, because there is no scheduling that can
      be done after this point.  */
-  if (DEFAULT_ABI == ABI_V4)
+  if (DEFAULT_ABI == ABI_V4
+      || current_function_calls_eh_return)
     {
       if (frame_reg_rtx != sp_reg_rtx)
 	  rs6000_emit_stack_tie ();