RE: [patch] [arm] New option for PIC offset unfixed

["Joey Ye" <joey.ye@arm.com>]

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> -----Original Message-----
> From: Richard Earnshaw
> Sent: Thursday, November 14, 2013 0:57
> To: Joey Ye
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [patch] [arm] New option for PIC offset unfixed
> 
> > So you are suggesting change like this:
> > + Target Report Var(arm_pic_data_is_text_relative) Init(-1)
> >
> > +   if (arm_pic_data_is_text_relative < 0 && TARGET_VXWORKS_RTP)
> > +     arm_pic_data_is_text_relative = 0;
> > +   else
> > +     arm_pic_data_is_text_relative = 1;
> >
> 
> No, use the global_options_set structure to find out if the user has set
the
> value.
Thank pointing this out. Here is the latest patch with global_options_set

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diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 7757e86..3af8293 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -2504,6 +2504,10 @@ arm_option_override (void)
 	arm_pic_register = pic_register;
     }
 
+  if (TARGET_VXWORKS_RTP
+      && !global_options_set.x_arm_pic_data_is_text_relative)
+    arm_pic_data_is_text_relative = 0;
+
   /* Enable -mfix-cortex-m3-ldrd by default for Cortex-M3 cores.  */
   if (fix_cm3_ldrd == 2)
     {
@@ -6020,7 +6024,7 @@ legitimize_pic_address (rtx orig, enum machine_mode mode, rtx reg)
 	   || (GET_CODE (orig) == SYMBOL_REF &&
 	       SYMBOL_REF_LOCAL_P (orig)))
 	  && NEED_GOT_RELOC
-	  && !TARGET_VXWORKS_RTP)
+	  && arm_pic_data_is_text_relative)
 	insn = arm_pic_static_addr (orig, reg);
       else
 	{
@@ -21498,7 +21502,7 @@ arm_assemble_integer (rtx x, unsigned int size, int aligned_p)
 	{
 	  /* See legitimize_pic_address for an explanation of the
 	     TARGET_VXWORKS_RTP check.  */
-	  if (TARGET_VXWORKS_RTP
+	  if (!arm_pic_data_is_text_relative
 	      || (GET_CODE (x) == SYMBOL_REF && !SYMBOL_REF_LOCAL_P (x)))
 	    fputs ("(GOT)", asm_out_file);
 	  else
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 1781b75..dbd841e 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -568,6 +568,10 @@ extern int prefer_neon_for_64bits;
 #define NEED_PLT_RELOC	0
 #endif
 
+#ifndef TARGET_DEFAULT_PIC_DATA_IS_TEXT_RELATIVE
+#define TARGET_DEFAULT_PIC_DATA_IS_TEXT_RELATIVE 1
+#endif
+
 /* Nonzero if we need to refer to the GOT with a PC-relative
    offset.  In other words, generate
 
diff --git a/gcc/config/arm/arm.opt b/gcc/config/arm/arm.opt
index 9b74038..fa0839a 100644
--- a/gcc/config/arm/arm.opt
+++ b/gcc/config/arm/arm.opt
@@ -158,6 +158,10 @@ mlong-calls
 Target Report Mask(LONG_CALLS)
 Generate call insns as indirect calls, if necessary
 
+mpic-data-is-text-relative
+Target Report Var(arm_pic_data_is_text_relative) Init(TARGET_DEFAULT_PIC_DATA_IS_TEXT_RELATIVE)
+Assume data segments are relative to text segment.
+
 mpic-register=
 Target RejectNegative Joined Var(arm_pic_register_string)
 Specify the register to be used for PIC addressing
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 863e518..fbe77e6 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -12120,6 +12120,12 @@ before execution begins.
 Specify the register to be used for PIC addressing.  The default is R10
 unless stack-checking is enabled, when R9 is used.
 
+@item -mpic-data-is-text-relative
+@opindex mpic-data-is-text-relative
+Assume that each data segments are relative to text segment at load time.
+Therefore, it permits addressing data using PC-relative operations.
+This option is on by default for targets other than VxWorks RTP.
+
 @item -mpoke-function-name
 @opindex mpoke-function-name
 Write the name of each function into the text section, directly