[Patch ARM] Turn on hot cold partitioning.

[Ramana Radhakrishnan]

Hi ,

This patch turns on hot cold partitioning for the ARM target. Given that
NOTE_INSN_SWITCH_SECTIONS gets created once - we should see
that this works.

Passed testing with cross on qemu - Simple handwritten tests for this
appear to work.

I'll commit this for 4.8 and would like some feedback for this.

regards,
Ramana


2012-02-29  Ramana Radhakrishnan  <ramana.radhakrishnan@linaro.org>

	* config/arm/arm.c (arm_option_override): Allow hot cold
	partitioning.
	(arm_reorg): Handle NOTE_INSN_SWITCH_TEXT_SECTIONS.
-------------- next part --------------
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index b58877b..b9fd116 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -1976,16 +1976,6 @@ arm_option_override (void)
   else
     max_insns_skipped = current_tune->max_insns_skipped;
 
-  /* Hot/Cold partitioning is not currently supported, since we can't
-     handle literal pool placement in that case.  */
-  if (flag_reorder_blocks_and_partition)
-    {
-      inform (input_location,
-	      "-freorder-blocks-and-partition not supported on this architecture");
-      flag_reorder_blocks_and_partition = 0;
-      flag_reorder_blocks = 1;
-    }
-
   if (flag_pic)
     /* Hoisting PIC address calculations more aggressively provides a small,
        but measurable, size reduction for PIC code.  Therefore, we decrease
@@ -13332,8 +13322,21 @@ arm_reorg (void)
   minipool_pad = 0;
 
   /* Scan all the insns and record the operands that will need fixing.  */
-  for (insn = next_nonnote_insn (insn); insn; insn = next_nonnote_insn (insn))
+  for (insn = next_nondebug_insn (insn); insn; insn = next_nondebug_insn (insn))
     {
+      if (NOTE_P (insn))
+	{
+	  if (NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
+	    {
+	      /* Given we cannot address a range greater than 4M go 
+		 ahead and increase the address sky high to force
+		 all pools before this note to be dumped.  */
+	      address += 0x400000;
+	    }
+	  else
+	    continue;
+	}
+
       if (TARGET_CIRRUS_FIX_INVALID_INSNS
           && (arm_cirrus_insn_p (insn)
 	      || GET_CODE (insn) == JUMP_INSN