* rs6000.h (INCOMING_RETURN_ADDR_RTX): New macro.

* aix.h (SETUP_FRAME_ADDRESSES): Define.
* rs6000.c [TARGET_AIX] (insn_after_throw): New static variable.
[TARGET_AIX] (rs6000_aix_emit_builtin_unwind_init): New function.
[TARGET_AIX] (rs6000_emit_eh_toc_restore): New function.
* rs6000-protos.h: Prototype rs6000_emit_eh_toc_restore,
rs6000_aix_emit_builtin_unwind_init.
* rs6000.md (eh_epilogue) [TARGET_AIX]: Call
rs6000_emit_eh_toc_restore on AIX.
(return_eh_si): Use r2.
(return_eh_di): Use r2.

* aix43.h: Turn on HAS_INIT_SECTION and LD_INIT_SWITCH,
since we're breaking binary compatibility anyway.


git-svn-id: https://gcc.gnu.org/svn/gcc/branches/newppc-branch@31882 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 170 insertions, 4 deletions

diff --git a/gcc/config/rs6000/ChangeLog b/gcc/config/rs6000/ChangeLog
index 1ab276c8fbd..96637cda885 100644
--- a/gcc/config/rs6000/ChangeLog
+++ b/gcc/config/rs6000/ChangeLog
@@ -1,3 +1,21 @@
+2000-02-09  Geoff Keating  <geoffk@cygnus.com>
+
+	* rs6000.h (INCOMING_RETURN_ADDR_RTX): New macro.
+
+	* aix.h (SETUP_FRAME_ADDRESSES): Define.
+	* rs6000.c [TARGET_AIX] (insn_after_throw): New static variable.
+	[TARGET_AIX] (rs6000_aix_emit_builtin_unwind_init): New function.
+	[TARGET_AIX] (rs6000_emit_eh_toc_restore): New function.
+	* rs6000-protos.h: Prototype rs6000_emit_eh_toc_restore,
+	rs6000_aix_emit_builtin_unwind_init.
+	* rs6000.md (eh_epilogue) [TARGET_AIX]: Call 
+	rs6000_emit_eh_toc_restore on AIX.
+	(return_eh_si): Use r2.
+	(return_eh_di): Use r2.
+
+	* aix43.h: Turn on HAS_INIT_SECTION and LD_INIT_SWITCH,
+	since we're breaking binary compatibility anyway.
+
 2000-02-09  Clinton Popetz  <cpopetz@cygnus.com>
 
 	* config/rs6000/rs6000-protos.h: (get_TOC_alias_set, uses_TOC,
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
index acc6d313bce..6a2eeb7b818 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
@@ -471,3 +471,11 @@ toc_section ()						\
 
 /* dwarf2out keys off this, but we don't have to have a real definition.  */
 #define UNALIGNED_INT_ASM_OP bite_me
+
+/* __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 with his.  */
+#define SETUP_FRAME_ADDRESSES() rs6000_aix_emit_builtin_unwind_init ()
+
diff --git a/gcc/config/rs6000/aix43.h b/gcc/config/rs6000/aix43.h
index 06b241e0773..3822c0a2aa3 100644
--- a/gcc/config/rs6000/aix43.h
+++ b/gcc/config/rs6000/aix43.h
@@ -197,7 +197,6 @@ do {									\
 #undef RS6000_CALL_GLUE
 #define RS6000_CALL_GLUE "{cror 31,31,31|nop}"
 
-#if 0
 /* AIX 4.2 and above provides initialization and finalization function
    support from linker command line.  */
 #undef HAS_INIT_SECTION
@@ -205,4 +204,3 @@ do {									\
 
 #undef LD_INIT_SWITCH
 #define LD_INIT_SWITCH "-binitfini"
-#endif
diff --git a/gcc/config/rs6000/rs6000-protos.h b/gcc/config/rs6000/rs6000-protos.h
index 031a49bc797..87a0cf3b852 100644
--- a/gcc/config/rs6000/rs6000-protos.h
+++ b/gcc/config/rs6000/rs6000-protos.h
@@ -92,7 +92,7 @@ extern void rs6000_fatal_bad_address PARAMS ((rtx));
 extern int stmw_operation PARAMS ((rtx, enum machine_mode));
 extern int mtcrf_operation PARAMS ((rtx, enum machine_mode));
 extern int lmw_operation PARAMS ((rtx, enum machine_mode));
-
+extern void rs6000_emit_eh_toc_restore PARAMS ((rtx));
 #endif /* RTX_CODE */
 
 #ifdef TREE_CODE
@@ -149,5 +149,6 @@ extern int uses_TOC PARAMS ((void));
 extern struct rtx_def *create_TOC_reference PARAMS ((rtx));
 extern void rs6000_emit_prologue PARAMS ((void));
 extern void rs6000_emit_load_toc_table PARAMS ((int));
+extern void rs6000_aix_emit_builtin_unwind_init PARAMS ((void));
 extern void rs6000_emit_epilogue PARAMS ((int));
 extern void debug_stack_info PARAMS ((rs6000_stack_t *));
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 41e9dffd810..ae3fce90027 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -4424,6 +4424,136 @@ create_TOC_reference(symbol)
 			ggc_alloc_string (toc_label_name, -1)))));
 }
 
+#if TARGET_AIX
+/* __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. 
+
+   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);
+
+  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, 
+				   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, r2;
+  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);
+  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 (trunc_int_for_mode (TARGET_32BIT 
+					       ? 0x80410014 
+					       : 0xE8410028, SImode)));
+
+  if (insn_after_throw == NULL_RTX)
+    abort();
+  emit_move_insn (opcode, insn_after_throw);
+  
+  emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
+  emit_label (loop_start);
+  
+  do_compare_rtx_and_jump (opcode, tocompare, NE, 1,
+			   SImode, NULL_RTX, 0, 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, 0, NULL_RTX,
+			   loop_exit);
+
+  mem = gen_rtx_MEM (Pmode, bottom_of_stack);
+  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));
+
+  emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
+  emit_jump (loop_start);
+  emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
+  emit_label (loop_exit);
+}
+#endif /* TARGET_AIX */
 
 /* This ties together stack memory 
    (MEM with an alias set of rs6000_sr_alias_set)
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 20710f28682..26ac7465409 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -2790,6 +2790,12 @@ do {									\
 #define ASM_OPEN_PAREN "("
 #define ASM_CLOSE_PAREN ")"
 
+/* Pick up the return address upon entry to a procedure. Used for
+   dwarf2 unwind information.  This also enables the table driven
+   mechanism.  */
+
+#define INCOMING_RETURN_ADDR_RTX   gen_rtx_REG (Pmode, LINK_REGISTER_REGNUM)
+
 /* Define results of standard character escape sequences.  */
 #define TARGET_BELL 007
 #define TARGET_BS 010
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index d5b0b3f81bc..7c59a797f63 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -25,7 +25,6 @@
 ;; Number	Use
 ;; 0		frsp for POWER machines
 ;; 0/v		blockage
-;; 1/v		nonlocal_goto_receiver for MINIMAL_TOC
 ;; 5		used to tie the stack contents and the stack pointer
 ;; 6		address of a word pointing to the TOC
 ;; 7		address of the TOC (more-or-less)
@@ -11237,6 +11236,10 @@
       operands[2] = r;
     }
 
+#if TARGET_AIX
+    rs6000_emit_eh_toc_restore (operands[1]);
+#endif
+
   emit_insn (gen_eh_reg_restore ());
 
   if (Pmode == SImode)
@@ -11300,6 +11303,7 @@
 (define_insn "return_eh_si"
   [(use (match_operand:SI 0 "register_operand" "l,c"))
    (return)
+   (use (reg:SI 2))
    (use (reg:SI 3))]
   "TARGET_32BIT"
   "@
@@ -11310,6 +11314,7 @@
 (define_insn "return_eh_di"
   [(use (match_operand:DI 0 "register_operand" "l,c"))
    (return)
+   (use (reg:DI 2))
    (use (reg:DI 3))]
   "TARGET_64BIT"
   "@