Re: [Patch] 2/3 MIPS support for builtin __builtin_flush_icache().

[David Daney <ddaney@avtrex.com>]

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Richard Sandiford wrote:
>
> OK with those three changes.  They're all trivial, so if it compiles,
> there's no need to retest.
>   
Thanks for reviewing this Richard.

This is the version I committed.  The only changes are those you suggested.

David Daney

2007-07-10  David Daney  <ddaney@avtrex.com>

    * config/mips/mips.h (ISA_HAS_SYNCI): New target capability
    predicate.
    (INITIALIZE_TRAMPOLINE): Emit clear_cache insn instead of  library
    call.
    * config/mips/mips.c (mips_expand_synci_loop): New function.
    * config/mips/mips.md (UNSPEC_CLEAR_HAZARD): New constant.
    (UNSPEC_RDHWR): Same.
    (UNSPEC_SYNCI): Same.
    (UNSPEC_SYNC): Same.
    (clear_cache): New expand.
    (sync): New insn.
    (synci): Same.
    (rdhwr): Same.
    (clear_hazard): Same.
    * config/mips/mips-protos.h (mips_expand_synci_loop): Declare
    function.
    * testsuite/gcc.target/mips/clear-cache-1.c: New test.
    * testsuite/gcc.target/mips/clear-cache-2.c: New test.


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Index: testsuite/gcc.target/mips/clear-cache-2.c
===================================================================
--- testsuite/gcc.target/mips/clear-cache-2.c	(revision 0)
+++ testsuite/gcc.target/mips/clear-cache-2.c	(revision 0)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-mips-options "-O2 -mips32" } */
+/* { dg-final { scan-assembler-not "synci" } } */
+/* { dg-final { scan-assembler-not "jr.hb" } } */
+/* { dg-final { scan-assembler "_flush_cache" } } */
+
+void f()
+{
+  int size = 40;
+  char *memory = __builtin_alloca(size);
+  __builtin___clear_cache(memory, memory + size);
+}
+
Index: testsuite/gcc.target/mips/clear-cache-1.c
===================================================================
--- testsuite/gcc.target/mips/clear-cache-1.c	(revision 0)
+++ testsuite/gcc.target/mips/clear-cache-1.c	(revision 0)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-mips-options "-O2 -mips32r2" } */
+/* { dg-final { scan-assembler "synci" } } */
+/* { dg-final { scan-assembler "jr.hb" } } */
+/* { dg-final { scan-assembler-not "_flush_cache" } } */
+
+void f()
+{
+  int size = 40;
+  char *memory = __builtin_alloca(size);
+  __builtin___clear_cache(memory, memory + size);
+}
+
Index: config/mips/mips.md
===================================================================
--- config/mips/mips.md	(revision 126536)
+++ config/mips/mips.md	(working copy)
@@ -50,6 +50,10 @@ (define_constants
    (UNSPEC_TLS_GET_TP		28)
    (UNSPEC_MFHC1		31)
    (UNSPEC_MTHC1		32)
+   (UNSPEC_CLEAR_HAZARD		33)
+   (UNSPEC_RDHWR		34)
+   (UNSPEC_SYNCI		35)
+   (UNSPEC_SYNC			36)
 
    (UNSPEC_ADDRESS_FIRST	100)
 
@@ -4221,6 +4225,69 @@ (define_insn "cprestore"
 }
   [(set_attr "type" "store")
    (set_attr "length" "4,12")])
+
+;; Expand in-line code to clear the instruction cache between operand[0] and
+;; operand[1].
+(define_expand "clear_cache"
+  [(match_operand 0 "pmode_register_operand")
+   (match_operand 1 "pmode_register_operand")]
+  ""
+  "
+{
+  if (ISA_HAS_SYNCI)
+    {
+      mips_expand_synci_loop (operands[0], operands[1]);
+      emit_insn (gen_sync ());
+      emit_insn (gen_clear_hazard ());
+    }
+  else if (mips_cache_flush_func && mips_cache_flush_func[0])
+    {
+      rtx len = gen_reg_rtx (Pmode);
+      emit_insn (gen_sub3_insn (len, operands[1], operands[0]));
+      /* Flush both caches.  We need to flush the data cache in case
+         the system has a write-back cache.  */
+      emit_library_call (gen_rtx_SYMBOL_REF (Pmode, mips_cache_flush_func),
+                         0, VOIDmode, 3, operands[0], Pmode,
+                         len, TYPE_MODE (integer_type_node),
+                         GEN_INT (3), TYPE_MODE (integer_type_node));
+   }
+  DONE;
+}")
+
+(define_insn "sync"
+  [(unspec_volatile [(const_int 0)] UNSPEC_SYNC)]
+  "ISA_HAS_SYNCI"
+  "sync")
+
+(define_insn "synci"
+  [(unspec_volatile [(match_operand 0 "pmode_register_operand" "d")]
+		    UNSPEC_SYNCI)]
+  "ISA_HAS_SYNCI"
+  "synci\t0(%0)")
+
+(define_insn "rdhwr"
+  [(set (match_operand:SI 0 "general_operand" "=d")
+        (unspec_volatile [(match_operand:SI 1 "const_int_operand" "n")]
+        UNSPEC_RDHWR))]
+  "ISA_HAS_SYNCI"
+  "rdhwr\t%0,$%1")
+
+(define_insn "clear_hazard"
+  [(unspec_volatile [(const_int 0)] UNSPEC_CLEAR_HAZARD)
+   (clobber (reg:SI 31))]
+  "ISA_HAS_SYNCI"
+{
+  return ".set\tpush\n"
+         "\t.set\tnoreorder\n"
+         "\t.set\tnomacro\n"
+         "\tbal\t1f\n"
+         "\tnop\n"
+         "1:\taddiu\t$31,$31,12\n"
+         "\tjr.hb\t$31\n"
+         "\tnop\n"
+         "\t.set\tpop";
+}
+  [(set_attr "length" "20")])
 \f
 ;; Block moves, see mips.c for more details.
 ;; Argument 0 is the destination
Index: config/mips/mips-protos.h
===================================================================
--- config/mips/mips-protos.h	(revision 126536)
+++ config/mips/mips-protos.h	(working copy)
@@ -1,6 +1,6 @@
 /* Prototypes of target machine for GNU compiler.  MIPS version.
    Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   1999, 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
    Contributed by A. Lichnewsky (lich@inria.inria.fr).
    Changed by Michael Meissner	(meissner@osf.org).
    64-bit r4000 support by Ian Lance Taylor (ian@cygnus.com) and
@@ -187,6 +187,7 @@ extern void mips_expand_call (rtx, rtx, 
 extern void mips_emit_fcc_reload (rtx, rtx, rtx);
 extern void mips_set_return_address (rtx, rtx);
 extern bool mips_expand_block_move (rtx, rtx, rtx);
+extern void mips_expand_synci_loop (rtx, rtx);
 
 extern void init_cumulative_args (CUMULATIVE_ARGS *, tree, rtx);
 extern void function_arg_advance (CUMULATIVE_ARGS *, enum machine_mode,
Index: config/mips/mips.c
===================================================================
--- config/mips/mips.c	(revision 126536)
+++ config/mips/mips.c	(working copy)
@@ -3883,6 +3883,33 @@ mips_block_move_loop (rtx dest, rtx src,
     mips_block_move_straight (dest, src, leftover);
 }
 \f
+
+/* Expand a loop of synci insns for the address range [BEGIN, END).  */
+
+void
+mips_expand_synci_loop (rtx begin, rtx end)
+{
+  rtx inc, label, cmp, cmp_result;
+
+  /* Load INC with the cache line size (rdhwr INC,$1). */
+  inc = gen_reg_rtx (SImode);
+  emit_insn (gen_rdhwr (inc, const1_rtx));
+
+  /* Loop back to here.  */
+  label = gen_label_rtx ();
+  emit_label (label);
+
+  emit_insn (gen_synci (begin));
+
+  cmp = gen_reg_rtx (Pmode);
+  mips_emit_binary (GTU, cmp, begin, end);
+
+  mips_emit_binary (PLUS, begin, begin, inc);
+
+  cmp_result = gen_rtx_EQ (VOIDmode, cmp, const0_rtx);
+  emit_jump_insn (gen_condjump (cmp_result, label));
+}
+\f
 /* Expand a movmemsi instruction.  */
 
 bool
Index: config/mips/mips.h
===================================================================
--- config/mips/mips.h	(revision 126536)
+++ config/mips/mips.h	(working copy)
@@ -804,6 +804,10 @@ extern const struct mips_rtx_cost_data *
 				 || ISA_MIPS32R2			\
 				 || ISA_MIPS64				\
 				 || TARGET_MIPS5500)
+
+/* ISA includes synci, jr.hb and jalr.hb.  */
+#define ISA_HAS_SYNCI ISA_MIPS32R2
+
 \f
 /* Add -G xx support.  */
 
@@ -2151,21 +2155,16 @@ typedef struct mips_args {
 
 #define INITIALIZE_TRAMPOLINE(ADDR, FUNC, CHAIN)			    \
 {									    \
-  rtx func_addr, chain_addr;						    \
+  rtx func_addr, chain_addr, end_addr;                                      \
 									    \
   func_addr = plus_constant (ADDR, 32);					    \
   chain_addr = plus_constant (func_addr, GET_MODE_SIZE (ptr_mode));	    \
   emit_move_insn (gen_rtx_MEM (ptr_mode, func_addr), FUNC);		    \
   emit_move_insn (gen_rtx_MEM (ptr_mode, chain_addr), CHAIN);		    \
-									    \
-  /* Flush both caches.  We need to flush the data cache in case	    \
-     the system has a write-back cache.  */				    \
-  /* ??? Should check the return value for errors.  */			    \
-  if (mips_cache_flush_func && mips_cache_flush_func[0])		    \
-    emit_library_call (gen_rtx_SYMBOL_REF (Pmode, mips_cache_flush_func),   \
-		       0, VOIDmode, 3, ADDR, Pmode,			    \
-		       GEN_INT (TRAMPOLINE_SIZE), TYPE_MODE (integer_type_node),\
-		       GEN_INT (3), TYPE_MODE (integer_type_node));	    \
+  end_addr = gen_reg_rtx (Pmode);					    \
+  emit_insn (gen_add3_insn (end_addr, copy_rtx (ADDR),			    \
+                            GEN_INT (TRAMPOLINE_SIZE)));		    \
+  emit_insn (gen_clear_cache (copy_rtx (ADDR), end_addr));		    \
 }
 \f
 /* Addressing modes, and classification of registers for them.  */