S/390: Hotpatching fixes.

2015-03-02  Dominik Vogt  <vogt@linux.vnet.ibm.com>

	    * config/s390/s390.c (s390_reorg): Move code to output nops after label
	    to s390_reorg ().
	    (s390_asm_output_function_label): Likewise.
	    * config/s390/s390.c (s390_asm_output_function_label):
	    Fix function label alignment with -mhtopatch.
	    * config/s390/s390.md ("unspecv"): New values UNSPECV_NOP_2_BYTE,
	    UNSPECV_NOP_4_BYTE and UNSPECV_NOP_6_BYTE
	    ("nop_2_byte"): New define_insn.
	    ("nop_4_byte"): Likewise.
	    ("nop_6_byte"): Likewise.
	    * doc/extend.texi (hotpatch): hotpatch attribute doc fixes.
	    * doc/invoke.texi (-mhotpatch): -mhotpatch doc fixes.

2015-03-02  Dominik Vogt  <vogt@linux.vnet.ibm.com>

	    * gcc.target/s390/hotpatch-21.c: New test for hotpatch alignment.
	    * gcc.target/s390/hotpatch-22.c: Likewise.
	    * gcc.target/s390/hotpatch-23.c: Likewise.
	    * gcc.target/s390/hotpatch-24.c: Likewise.
	    * gcc.target/s390/hotpatch-2.c: Also check hotpatch alignment.
	    * gcc.target/s390/hotpatch-1.c: Update expected output.
	    * gcc.target/s390/hotpatch-2.c: Likewise.
	    * gcc.target/s390/hotpatch-3.c: Likewise.
	    * gcc.target/s390/hotpatch-4.c: Likewise.
	    * gcc.target/s390/hotpatch-5.c: Likewise.
	    * gcc.target/s390/hotpatch-6.c: Likewise.
	    * gcc.target/s390/hotpatch-7.c: Likewise.
	    * gcc.target/s390/hotpatch-8.c: Likewise.
	    * gcc.target/s390/hotpatch-9.c: Likewise.
	    * gcc.target/s390/hotpatch-10.c: Likewise.
	    * gcc.target/s390/hotpatch-11.c: Likewise.
	    * gcc.target/s390/hotpatch-12.c: Likewise.
	    * gcc.target/s390/hotpatch-13.c: Likewise.
	    * gcc.target/s390/hotpatch-14.c: Likewise.
	    * gcc.target/s390/hotpatch-15.c: Likewise.
	    * gcc.target/s390/hotpatch-16.c: Likewise.
	    * gcc.target/s390/hotpatch-17.c: Likewise.
	    * gcc.target/s390/hotpatch-18.c: Likewise.
	    * gcc.target/s390/hotpatch-19.c: Likewise.




git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@221381 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 66 insertions, 25 deletions

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 593c0cc8ee2..d2b87046b3a 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -5295,6 +5295,7 @@ s390_asm_output_function_label (FILE *asm_out_file, const char *fname,
 
   if (hotpatch_p)
     {
+      unsigned int function_alignment;
       int i;
 
       /* Add a trampoline code area before the function label and initialize it
@@ -5308,34 +5309,14 @@ s390_asm_output_function_label (FILE *asm_out_file, const char *fname,
 	 stored directly before the label without crossing a cacheline
 	 boundary.  All this is necessary to make sure the trampoline code can
 	 be changed atomically.  */
+      function_alignment = MAX (8, DECL_ALIGN (decl) / BITS_PER_UNIT);
+      if (! DECL_USER_ALIGN (decl))
+	function_alignment = MAX (function_alignment,
+				  (unsigned int) align_functions);
+      ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (function_alignment));
     }
 
   ASM_OUTPUT_LABEL (asm_out_file, fname);
-
-  /* Output a series of NOPs after the function label.  */
-  if (hotpatch_p)
-    {
-      while (hw_after > 0)
-	{
-	  if (hw_after >= 3 && TARGET_CPU_ZARCH)
-	    {
-	      asm_fprintf (asm_out_file, "\tbrcl\t\t0,0\n");
-	      hw_after -= 3;
-	    }
-	  else if (hw_after >= 2)
-	    {
-	      gcc_assert (hw_after == 2 || !TARGET_CPU_ZARCH);
-	      asm_fprintf (asm_out_file, "\tnop\t0\n");
-	      hw_after -= 2;
-	    }
-	  else
-	    {
-	      gcc_assert (hw_after == 1);
-	      asm_fprintf (asm_out_file, "\tnopr\t%%r7\n");
-	      hw_after -= 1;
-	    }
-	}
-    }
 }
 
 /* Output machine-dependent UNSPECs occurring in address constant X
@@ -11368,6 +11349,7 @@ static void
 s390_reorg (void)
 {
   bool pool_overflow = false;
+  int hw_before, hw_after;
 
   /* Make sure all splits have been performed; splits after
      machine_dependent_reorg might confuse insn length counts.  */
@@ -11503,6 +11485,40 @@ s390_reorg (void)
       if (insn_added_p)
 	shorten_branches (get_insns ());
     }
+
+  s390_function_num_hotpatch_hw (current_function_decl, &hw_before, &hw_after);
+  if (hw_after > 0)
+    {
+      rtx_insn *insn;
+
+      /* Inject nops for hotpatching. */
+      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+	{
+	  if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG)
+	    break;
+	}
+      gcc_assert (insn);
+      /* Output a series of NOPs after the NOTE_INSN_FUNCTION_BEG.  */
+      while (hw_after > 0)
+	{
+	  if (hw_after >= 3 && TARGET_CPU_ZARCH)
+	    {
+	      insn = emit_insn_after (gen_nop_6_byte (), insn);
+	      hw_after -= 3;
+	    }
+	  else if (hw_after >= 2)
+	    {
+	      insn = emit_insn_after (gen_nop_4_byte (), insn);
+	      hw_after -= 2;
+	    }
+	  else
+	    {
+	      insn = emit_insn_after (gen_nop_2_byte (), insn);
+	      hw_after -= 1;
+	    }
+	}
+      gcc_assert (hw_after == 0);
+    }
 }
 
 /* Return true if INSN is a fp load insn writing register REGNO.  */
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index bf698b1cf81..76dca0a68ae 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -153,6 +153,11 @@
    UNSPECV_CAS
    UNSPECV_ATOMIC_OP
 
+   ; Hotpatching (unremovable NOPs)
+   UNSPECV_NOP_2_BYTE
+   UNSPECV_NOP_4_BYTE
+   UNSPECV_NOP_6_BYTE
+
    ; Transactional Execution support
    UNSPECV_TBEGIN
    UNSPECV_TBEGIN_TDB
@@ -9705,6 +9710,26 @@
   "lr\t1,1"
   [(set_attr "op_type" "RR")])
 
+;;- Undeletable nops (used for hotpatching)
+
+(define_insn "nop_2_byte"
+  [(unspec_volatile [(const_int 0)] UNSPECV_NOP_2_BYTE)]
+  ""
+  "nopr\t%%r7"
+  [(set_attr "op_type" "RR")])
+
+(define_insn "nop_4_byte"
+  [(unspec_volatile [(const_int 0)] UNSPECV_NOP_4_BYTE)]
+  ""
+  "nop\t0"
+  [(set_attr "op_type" "RX")])
+
+(define_insn "nop_6_byte"
+  [(unspec_volatile [(const_int 0)] UNSPECV_NOP_6_BYTE)]
+  "TARGET_CPU_ZARCH"
+  "brcl\t0, 0"
+  [(set_attr "op_type" "RIL")])
+
 
 ;
 ; Special literal pool access instruction pattern(s).