From 8325c9b804e4165308944bf947100625603a9486 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@gcc.gnu.org>
Date: Tue, 9 Mar 2010 21:11:53 +0100
Subject: [PATCH] re PR debug/43293 (Invalid unwind info for i?86 -fpic)

	PR debug/43293
	* config/i386/t-i386 (i386.o): Depend on debug.h and dwarf2out.h.
	* config/i386/i386.c: Include debug.h and dwarf2out.h.
	(ix86_file_end): If dwarf2out_do_cfi_asm (), emit .cfi_startproc
	and .cfi_endproc around the pic thunks.
	(output_set_got): For TARGET_DEEP_BRANCH_PREDICTION pic, ensure
	all queued unwind info register saves are saved before the call.
	For !TARGET_DEEP_BRANCH_PREDICTION pic, ensure the call is
	considered as sp-=4 for unwind info and the pop as sp+=4 which
	also clobbers dest, but doesn't actually restore it.

From-SVN: r157325
---
 gcc/config/i386/i386.c | 67 ++++++++++++++++++++++++++++++++++++++++--
 gcc/config/i386/t-i386 |  2 +-
 2 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index ab242a63da6..087c30ff92c 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -53,6 +53,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "tm-constrs.h"
 #include "params.h"
 #include "cselib.h"
+#include "debug.h"
+#include "dwarf2out.h"
 
 static rtx legitimize_dllimport_symbol (rtx, bool);
 
@@ -7584,6 +7586,9 @@ ix86_file_end (void)
   for (regno = 0; regno < 8; ++regno)
     {
       char name[32];
+#ifdef DWARF2_UNWIND_INFO
+      bool do_cfi;
+#endif
 
       if (! ((pic_labels_used >> regno) & 1))
 	continue;
@@ -7629,10 +7634,19 @@ ix86_file_end (void)
 	  ASM_OUTPUT_LABEL (asm_out_file, name);
 	}
 
+#ifdef DWARF2_UNWIND_INFO
+      do_cfi = dwarf2out_do_cfi_asm ();
+      if (do_cfi)
+	fprintf (asm_out_file, "\t.cfi_startproc\n");
+#endif
       xops[0] = gen_rtx_REG (Pmode, regno);
       xops[1] = gen_rtx_MEM (Pmode, stack_pointer_rtx);
       output_asm_insn ("mov%z0\t{%1, %0|%0, %1}", xops);
       output_asm_insn ("ret", xops);
+#ifdef DWARF2_UNWIND_INFO
+      if (do_cfi)
+	fprintf (asm_out_file, "\t.cfi_endproc\n");
+#endif
     }
 
   if (NEED_INDICATE_EXEC_STACK)
@@ -7673,7 +7687,24 @@ output_set_got (rtx dest, rtx label ATTRIBUTE_UNUSED)
       if (!flag_pic)
 	output_asm_insn ("mov%z0\t{%2, %0|%0, %2}", xops);
       else
-	output_asm_insn ("call\t%a2", xops);
+	{
+	  output_asm_insn ("call\t%a2", xops);
+#ifdef DWARF2_UNWIND_INFO
+	  /* The call to next label acts as a push.  */
+	  if (dwarf2out_do_frame ())
+	    {
+	      rtx insn;
+	      start_sequence ();
+	      insn = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,
+					     gen_rtx_PLUS (Pmode,
+							   stack_pointer_rtx,
+							   GEN_INT (-4))));
+	      RTX_FRAME_RELATED_P (insn) = 1;
+	      dwarf2out_frame_debug (insn, true);
+	      end_sequence ();
+	    }
+#endif
+	}
 
 #if TARGET_MACHO
       /* Output the Mach-O "canonical" label name ("Lxx$pb") here too.  This
@@ -7686,7 +7717,27 @@ output_set_got (rtx dest, rtx label ATTRIBUTE_UNUSED)
 				 CODE_LABEL_NUMBER (XEXP (xops[2], 0)));
 
       if (flag_pic)
-	output_asm_insn ("pop%z0\t%0", xops);
+	{
+	  output_asm_insn ("pop%z0\t%0", xops);
+#ifdef DWARF2_UNWIND_INFO
+	  /* The pop is a pop and clobbers dest, but doesn't restore it
+	     for unwind info purposes.  */
+	  if (dwarf2out_do_frame ())
+	    {
+	      rtx insn;
+	      start_sequence ();
+	      insn = emit_insn (gen_rtx_SET (VOIDmode, dest, const0_rtx));
+	      dwarf2out_frame_debug (insn, true);
+	      insn = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,
+					     gen_rtx_PLUS (Pmode,
+							   stack_pointer_rtx,
+							   GEN_INT (4))));
+	      RTX_FRAME_RELATED_P (insn) = 1;
+	      dwarf2out_frame_debug (insn, true);
+	      end_sequence ();
+	    }
+#endif
+	}
     }
   else
     {
@@ -7694,6 +7745,18 @@ output_set_got (rtx dest, rtx label ATTRIBUTE_UNUSED)
       get_pc_thunk_name (name, REGNO (dest));
       pic_labels_used |= 1 << REGNO (dest);
 
+#ifdef DWARF2_UNWIND_INFO
+      /* Ensure all queued register saves are flushed before the
+	 call.  */
+      if (dwarf2out_do_frame ())
+	{
+	  rtx insn;
+	  start_sequence ();
+	  insn = emit_barrier ();
+	  end_sequence ();
+	  dwarf2out_frame_debug (insn, false);
+	}
+#endif
       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);
diff --git a/gcc/config/i386/t-i386 b/gcc/config/i386/t-i386
index 55ddd1eeb55..ba3b4e4b42a 100644
--- a/gcc/config/i386/t-i386
+++ b/gcc/config/i386/t-i386
@@ -23,7 +23,7 @@ i386.o: $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RECOG_H) $(EXPR_H) $(OPTABS_H) toplev.h $(BASIC_BLOCK_H) \
   $(GGC_H) $(TARGET_H) $(TARGET_DEF_H) langhooks.h $(CGRAPH_H) \
   $(TREE_GIMPLE_H) $(DWARF2_H) $(DF_H) tm-constrs.h $(PARAMS_H) \
-  i386-builtin-types.inc
+  i386-builtin-types.inc debug.h dwarf2out.h
 
 i386-c.o: $(srcdir)/config/i386/i386-c.c \
   $(srcdir)/config/i386/i386-protos.h $(CONFIG_H) $(SYSTEM_H) coretypes.h \
-- 
2.30.2