re PR target/51784 (PIC register not correctly preserved in nested funcs / with non-local goto)

gcc/

	PR target/51784
	* config/i386/i386.c (output_set_got) [TARGET_MACHO]: Adjust to emit a
	second label for nonlocal goto receivers. Don't output pic base labels
	unless we're producing PIC; mark that action unreachable().
	(ix86_save_reg): If the function contains a nonlocal label, save the
	PIC base reg.
	* config/darwin-protos.h (machopic_should_output_picbase_label): New.
	* gcc/config/darwin.c (emitted_pic_label_num): New GTY. 
	(update_pic_label_number_if_needed): New.
	(machopic_output_function_base_name): Adjust for nonlocal receiver
	case.
	(machopic_should_output_picbase_label): New.
	* config/i386/i386.md (enum unspecv): UNSPECV_NLGR: New.
	(nonlocal_goto_receiver): New insn and split.

From-SVN: r201086

gcc/config/darwin-protos.h

@@ -25,6 +25,7 @@ extern void machopic_validate_stub_or_non_lazy_ptr (const char *);
 extern void machopic_output_function_base_name (FILE *);
 extern const char *machopic_indirection_name (rtx, bool);
 extern const char *machopic_mcount_stub_name (void);
+extern bool machopic_should_output_picbase_label (void);
 
 #ifdef RTX_CODE
 

gcc/config/darwin.c

@@ -369,14 +369,13 @@ machopic_gen_offset (rtx orig)
 
 static GTY(()) const char * function_base_func_name;
 static GTY(()) int current_pic_label_num;
+static GTY(()) int emitted_pic_label_num;
 
-void
-machopic_output_function_base_name (FILE *file)
+static void
+update_pic_label_number_if_needed (void)
 {
   const char *current_name;
 
-  /* If dynamic-no-pic is on, we should not get here.  */
-  gcc_assert (!MACHO_DYNAMIC_NO_PIC_P);
   /* When we are generating _get_pc thunks within stubs, there is no current
      function.  */
   if (current_function_decl)
@@ -394,7 +393,28 @@ machopic_output_function_base_name (FILE *file)
       ++current_pic_label_num;
       function_base_func_name = "L_machopic_stub_dummy";
     }
-  fprintf (file, "L%011d$pb", current_pic_label_num);
+}
+
+void
+machopic_output_function_base_name (FILE *file)
+{
+  /* If dynamic-no-pic is on, we should not get here.  */
+  gcc_assert (!MACHO_DYNAMIC_NO_PIC_P);
+
+  update_pic_label_number_if_needed ();
+  fprintf (file, "L%d$pb", current_pic_label_num);
+}
+
+bool
+machopic_should_output_picbase_label (void)
+{
+  update_pic_label_number_if_needed ();
+
+  if (current_pic_label_num == emitted_pic_label_num)
+    return false;
+
+  emitted_pic_label_num = current_pic_label_num;
+  return true;
 }
 
 /* The suffix attached to non-lazy pointer symbols.  */

gcc/config/i386/i386.c

@@ -8822,17 +8822,12 @@ output_set_got (rtx dest, rtx label ATTRIBUTE_UNUSED)
 
   if (!flag_pic)
     {
-      xops[2] = gen_rtx_LABEL_REF (Pmode, label ? label : gen_label_rtx ());
+      if (TARGET_MACHO)
+	/* We don't need a pic base, we're not producing pic.  */
+	gcc_unreachable ();
 
+      xops[2] = gen_rtx_LABEL_REF (Pmode, label ? label : gen_label_rtx ());
       output_asm_insn ("mov%z0\t{%2, %0|%0, %2}", xops);
-
-#if TARGET_MACHO
-      /* Output the Mach-O "canonical" label name ("Lxx$pb") here too.  This
-         is what will be referenced by the Mach-O PIC subsystem.  */
-      if (!label)
-	ASM_OUTPUT_LABEL (asm_out_file, MACHOPIC_FUNCTION_BASE_NAME);
-#endif
-
       targetm.asm_out.internal_label (asm_out_file, "L",
 				      CODE_LABEL_NUMBER (XEXP (xops[2], 0)));
     }
@@ -8845,12 +8840,18 @@ output_set_got (rtx dest, rtx label ATTRIBUTE_UNUSED)
       xops[2] = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (name));
       xops[2] = gen_rtx_MEM (QImode, xops[2]);
       output_asm_insn ("call\t%X2", xops);
-      /* Output the Mach-O "canonical" label name ("Lxx$pb") here too.  This
-         is what will be referenced by the Mach-O PIC subsystem.  */
+
 #if TARGET_MACHO
-      if (!label)
+      /* Output the Mach-O "canonical" pic base label name ("Lxx$pb") here.
+         This is what will be referenced by the Mach-O PIC subsystem.  */
+      if (machopic_should_output_picbase_label () || !label)
 	ASM_OUTPUT_LABEL (asm_out_file, MACHOPIC_FUNCTION_BASE_NAME);
-      else
+
+      /* When we are restoring the pic base at the site of a nonlocal label,
+         and we decided to emit the pic base above, we will still output a
+         local label used for calculating the correction offset (even though
+         the offset will be 0 in that case).  */
+      if (label)
         targetm.asm_out.internal_label (asm_out_file, "L",
 					   CODE_LABEL_NUMBER (label));
 #endif
@@ -8932,7 +8933,8 @@ ix86_save_reg (unsigned int regno, bool maybe_eh_return)
       && (df_regs_ever_live_p (REAL_PIC_OFFSET_TABLE_REGNUM)
 	  || crtl->profile
 	  || crtl->calls_eh_return
-	  || crtl->uses_const_pool))
+	  || crtl->uses_const_pool
+	  || cfun->has_nonlocal_label))
     return ix86_select_alt_pic_regnum () == INVALID_REGNUM;
 
   if (crtl->calls_eh_return && maybe_eh_return)

gcc/config/i386/i386.md

@@ -222,6 +222,8 @@
   UNSPECV_XEND
   UNSPECV_XABORT
   UNSPECV_XTEST
+
+  UNSPECV_NLGR
 ])
 
 ;; Constants to represent rounding modes in the ROUND instruction
@@ -16227,7 +16229,38 @@
     emit_insn (gen_set_got (pic_offset_table_rtx));
   DONE;
 })
-
+
+(define_insn_and_split "nonlocal_goto_receiver"
+  [(unspec_volatile [(const_int 0)] UNSPECV_NLGR)]
+  "TARGET_MACHO && !TARGET_64BIT && flag_pic"
+{
+  if (crtl->uses_pic_offset_table)
+    return "#";
+  else
+    return ""; /* No pic reg restore needed.  */
+}
+  "&& reload_completed"
+  [(const_int 0)]
+{
+  if (crtl->uses_pic_offset_table)
+    {
+      rtx xops[3];
+      rtx label_rtx = gen_label_rtx ();
+      rtx tmp;
+
+      /* Get a new pic base.  */
+      emit_insn (gen_set_got_labelled (pic_offset_table_rtx, label_rtx));
+      /* Correct this with the offset from the new to the old.  */
+      xops[0] = xops[1] = pic_offset_table_rtx;
+      label_rtx = gen_rtx_LABEL_REF (SImode, label_rtx);
+      tmp = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, label_rtx),
+			    UNSPEC_MACHOPIC_OFFSET);
+      xops[2] = gen_rtx_CONST (Pmode, tmp);
+      ix86_expand_binary_operator (MINUS, SImode, xops);
+    }
+  DONE;
+})
+
 ;; Avoid redundant prefixes by splitting HImode arithmetic to SImode.
 
 (define_split

gcc/testsuite/ChangeLog

+2013-07-20  Iain Sandoe  <iain@codesourcery.com>
+
+	PR target/51784
+	* config/i386/i386.c (output_set_got) [TARGET_MACHO]: Adjust to emit a
+	second label for nonlocal goto receivers. Don't output pic base labels
+	unless we're producing PIC; mark that action unreachable().
+	(ix86_save_reg): If the function contains a nonlocal label, save the
+	PIC base reg.
+	* config/darwin-protos.h (machopic_should_output_picbase_label): New.
+	* gcc/config/darwin.c (emitted_pic_label_num): New GTY. 
+	(update_pic_label_number_if_needed): New.
+	(machopic_output_function_base_name): Adjust for nonlocal receiver
+	case.
+	(machopic_should_output_picbase_label): New.
+	* config/i386/i386.md (enum unspecv): UNSPECV_NLGR: New.
+	(nonlocal_goto_receiver): New insn and split.
+
 2013-07-20  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* gcc.target/aarch64/vabs_intrinsic_1.c: New file.