msp430-protos.h: Add prototypes for new functions.

	* config/msp430/msp430-protos.h: Add prototypes for new functions.
	* config/msp430/msp430.c (msp430_preserve_reg_p): Add support for
	interrupt handlers.
	(is_attr_func): New function.
	(msp430_is_interrupt_func): New function.
	(is_naked_func): New function.
	(is_reentrant_func): New function.
	(is_critical_func): New function.
	(msp430_start_function): Add annotations for function attributes.
	(msp430_attr): New function.
	(msp430_attribute_table): New.
	(msp430_function_section): New function.
	(TARGET_ASM_FUNCTION_SECTION): Define.
	(msp430_builtin): New enum.
	(msp430_init_builtins): New function.
	(msp430_builtin_devl): New function.
	(msp430_expand_builtin): New function.
	(TARGET_INIT_BUILTINS): Define.
	(TARGET_EXPAND_BUILTINS): Define.
	(TARGET_BUILTIN_DECL): Define.
	(msp430_expand_prologue): Add support for naked, interrupt,
	critical and reentrant functions.
	(msp430_expand_epilogue): Likewise.
	(msp430_print_operand): Handle 'O' character.
	* config/msp430/msp430.h (TARGET_CPU_CPP_BUILTINS): Define
	NO_TRAMPOLINES.
	* config/msp430/msp430.md (unspec): Add UNS_DINT, UNS_EINT,
	UNS_PUSH_INTR, UNS_POP_INTR, UNS_BIC_SR, UNS_BIS_SR.
	(pushm): Use a 'n' rather than an 'i' constraint.
	(msp_return): Add generation of the interrupt return instruction.
	(disable_interrupts): New pattern.
	(enable_interrupts): New pattern.
	(push_intr_state): New pattern.
	(pop_intr_state): New pattern.
	(bic_SR): New pattern.
	(bis_SR): New pattern.
	* doc/extend.texi: Document MSP430 function attributes and builtin
	functions.

From-SVN: r202645

5 files changed, 365 insertions, 20 deletions

diff --git a/gcc/config/msp430/constraints.md b/gcc/config/msp430/constraints.md
index baacf92..ea53481 100644
--- a/gcc/config/msp430/constraints.md
+++ b/gcc/config/msp430/constraints.md
@@ -70,5 +70,3 @@
 		  (match_test ("IN_RANGE (INTVAL (XEXP (XEXP (op, 0), 1)), -1 << 15, (1 << 15)-1)"))))
 	(match_code "reg" "0")
 	)))
-  
-
diff --git a/gcc/config/msp430/msp430-protos.h b/gcc/config/msp430/msp430-protos.h
index df90d95..f116855 100644
--- a/gcc/config/msp430/msp430-protos.h
+++ b/gcc/config/msp430/msp430-protos.h
@@ -21,6 +21,7 @@
 #ifndef GCC_MSP430_PROTOS_H
 #define GCC_MSP430_PROTOS_H
 
+rtx	msp430_eh_return_stackadj_rtx (void);
 void	msp430_expand_eh_return (rtx);
 void	msp430_expand_epilogue (int);
 void	msp430_expand_helper (rtx *operands, const char *, bool);
@@ -32,13 +33,14 @@ int	msp430_hard_regno_nregs (int, enum machine_mode);
 rtx	msp430_incoming_return_addr_rtx (void);
 void	msp430_init_cumulative_args (CUMULATIVE_ARGS *, tree, rtx, tree, int);
 int	msp430_initial_elimination_offset (int, int);
+bool    msp430_is_interrupt_func (void);
 const char * msp430x_logical_shift_right (rtx);
+bool	msp430_modes_tieable_p (enum machine_mode, enum machine_mode);
 void	msp430_output_labelref (FILE *, const char *);
 void	msp430_register_pragmas (void);
 rtx	msp430_return_addr_rtx (int);
 void	msp430_split_movsi (rtx *);
 rtx	msp430_subreg (enum machine_mode, rtx, enum machine_mode, int);
-rtx	msp430_eh_return_stackadj_rtx (void);
-bool	msp430_modes_tieable_p (enum machine_mode, enum machine_mode);
+void    msp430_start_function (FILE *, const char *, tree);
 
 #endif /* GCC_MSP430_PROTOS_H */
diff --git a/gcc/config/msp430/msp430.c b/gcc/config/msp430/msp430.c
index 2e6705d..9384d32 100644
--- a/gcc/config/msp430/msp430.c
+++ b/gcc/config/msp430/msp430.c
@@ -120,7 +120,7 @@ msp430_option_override (void)
     msp430x = true;
 
   if (TARGET_LARGE && !msp430x)
-    error ("-mlarge requires a 430X-compatible -mcpu=");
+    error ("-mlarge requires a 430X-compatible -mmcu=");
 
   if (flag_exceptions || flag_non_call_exceptions
       || flag_unwind_tables || flag_asynchronous_unwind_tables)
@@ -208,10 +208,9 @@ msp430_can_eliminate (const int from_reg ATTRIBUTE_UNUSED,
 
 /* Implements INITIAL_ELIMINATION_OFFSET.  */
 int
-msp430_initial_elimination_offset (int from ATTRIBUTE_UNUSED,
-				   int to ATTRIBUTE_UNUSED)
+msp430_initial_elimination_offset (int from, int to)
 {
-  int rv = 0; /* as if arg to arg */
+  int rv = 0; /* As if arg to arg.  */
 
   msp430_compute_frame_info ();
 
@@ -763,6 +762,10 @@ static bool msp430_rtx_costs (rtx   x ATTRIBUTE_UNUSED,
    |                    |
    | PC from call       |  (2 bytes for 430, 4 for TARGET_LARGE)
    |                    |
+   +--------------------+
+   | SR if this func has|
+   | been called via an |
+   | interrupt.         |
    +--------------------+  <-- SP before prologue, also AP
    |                    |
    | Saved Regs         |  (2 bytes per reg for 430, 4 per for TARGET_LARGE)
@@ -806,6 +809,12 @@ msp430_preserve_reg_p (int regno)
   if (fixed_regs [regno])
     return false;
 
+  /* Interrupt handlers save all registers they use, even
+     ones which are call saved.  If they call other functions
+     then *every* register is saved.  */
+  if (msp430_is_interrupt_func ())
+    return ! crtl->is_leaf || df_regs_ever_live_p (regno);
+
   if (!call_used_regs [regno]
       && df_regs_ever_live_p (regno))
     return true;
@@ -825,7 +834,7 @@ msp430_compute_frame_info (void)
   cfun->machine->framesize_locals = get_frame_size ();
   cfun->machine->framesize_outgoing = crtl->outgoing_args_size;
 
-  for (i = 0; i < 16; i ++)
+  for (i = 0; i < ARG_POINTER_REGNUM; i ++)
     if (msp430_preserve_reg_p (i))
       {
 	cfun->machine->need_to_save [i] = 1;
@@ -842,6 +851,38 @@ msp430_compute_frame_info (void)
 			      + cfun->machine->framesize_outgoing);
 }
 
+static inline bool
+is_attr_func (const char * attr)
+{
+  return lookup_attribute (attr, DECL_ATTRIBUTES (current_function_decl)) != NULL_TREE;
+}
+
+/* Returns true if the current function has the "interrupt" attribute.  */
+
+bool
+msp430_is_interrupt_func (void)
+{
+  return is_attr_func ("interrupt");
+}
+
+static inline bool
+is_naked_func (void)
+{
+  return is_attr_func ("naked");
+}
+
+static inline bool
+is_reentrant_func (void)
+{
+  return is_attr_func ("reentrant");
+}
+
+static inline bool
+is_critical_func (void)
+{
+  return is_attr_func ("critical");
+}
+
 #undef  TARGET_ASM_FUNCTION_PROLOGUE
 #define TARGET_ASM_FUNCTION_PROLOGUE	msp430_start_function
 
@@ -851,6 +892,21 @@ msp430_start_function (FILE *outfile, HOST_WIDE_INT hwi_local ATTRIBUTE_UNUSED)
   int r, n;
 
   fprintf (outfile, "; start of function\n");
+
+  if (DECL_ATTRIBUTES (current_function_decl) != NULL_TREE)
+    {
+      fprintf (outfile, "; attributes: ");
+      if (is_naked_func ())
+	fprintf (outfile, "naked ");
+      if (msp430_is_interrupt_func ())
+	fprintf (outfile, "interrupt ");
+      if (is_reentrant_func ())
+	fprintf (outfile, "reentrant ");
+      if (is_critical_func ())
+	fprintf (outfile, "critical ");
+      fprintf (outfile, "\n");
+    }
+
   fprintf (outfile, "; framesize_regs:     %d\n", cfun->machine->framesize_regs);
   fprintf (outfile, "; framesize_locals:   %d\n", cfun->machine->framesize_locals);
   fprintf (outfile, "; framesize_outgoing: %d\n", cfun->machine->framesize_outgoing);
@@ -860,7 +916,7 @@ msp430_start_function (FILE *outfile, HOST_WIDE_INT hwi_local ATTRIBUTE_UNUSED)
 
   n = 0;
   fprintf (outfile, "; saved regs:");
-  for (r = 0; r < 16; r++)
+  for (r = 0; r < ARG_POINTER_REGNUM; r++)
     if (cfun->machine->need_to_save [r])
       {
 	fprintf (outfile, " %s", reg_names [r]);
@@ -899,6 +955,215 @@ increment_stack (HOST_WIDE_INT amount)
     }
 }
 
+/* Verify MSP430 specific attributes.  */
+
+static tree
+msp430_attr (tree * node,
+	     tree   name,
+	     tree   args,
+	     int    flags ATTRIBUTE_UNUSED,
+	     bool * no_add_attrs)
+{
+  gcc_assert (DECL_P (* node));
+
+  if (args != NULL)
+    {
+      tree value = TREE_VALUE (args);
+
+      switch (TREE_CODE (value))
+	{
+	case STRING_CST:
+	  if (   strcmp (TREE_STRING_POINTER (value), "reset")
+	      && strcmp (TREE_STRING_POINTER (value), "nmi")
+	      && strcmp (TREE_STRING_POINTER (value), "watchdog"))
+	    /* Allow the attribute to be added - the linker script
+	       being used may still recognise this name.  */
+	    warning (OPT_Wattributes,
+		     "unrecognised interrupt vector argument of %qE attribute",
+		     name);
+	  break;
+
+	case INTEGER_CST:
+	  if (TREE_INT_CST_LOW (value) > 31)
+	    /* Allow the attribute to be added - the linker script
+	       being used may still recognise this value.  */
+	    warning (OPT_Wattributes,
+		     "numeric argument of %qE attribute must be in range 0..31",
+		     name);
+	  break;
+
+	default:
+	  warning (OPT_Wattributes,
+		   "argument of %qE attribute is not a string constant or number",
+		   name);
+	  *no_add_attrs = true;
+	  break;
+	}
+    }
+
+  if (TREE_CODE (* node) != FUNCTION_DECL)
+    {
+      warning (OPT_Wattributes,
+	       "%qE attribute only applies to functions",
+	       name);
+      * no_add_attrs = true;
+    }
+
+  /* FIXME: We ought to check that the interrupt handler
+     attribute has been applied to a void function.  */
+  /* FIXME: We should check that reentrant and critical
+     functions are not naked and that critical functions
+     are not reentrant.  */
+
+  return NULL_TREE;
+}
+
+#undef  TARGET_ATTRIBUTE_TABLE
+#define TARGET_ATTRIBUTE_TABLE		msp430_attribute_table
+
+/* Table of MSP430-specific attributes.  */
+const struct attribute_spec msp430_attribute_table[] =
+{
+  /* Name          min_len  decl_req,    fn_type_req,    affects_type_identity
+                       max_len,  type_req,        handler.  */
+  { "interrupt",      0, 1, true,  false, false, msp430_attr, false },
+  { "naked",          0, 0, true,  false, false, msp430_attr, false },
+  { "reentrant",      0, 0, true,  false, false, msp430_attr, false },
+  { "critical",       0, 0, true,  false, false, msp430_attr, false },
+  { NULL,             0, 0, false, false, false, NULL,        false }
+};
+
+void
+msp430_start_function (FILE *file, const char *name, tree decl)
+{
+  tree int_attr;
+
+  int_attr = lookup_attribute ("interrupt", DECL_ATTRIBUTES (decl));
+  if (int_attr != NULL_TREE)
+    {
+      tree intr_vector = TREE_VALUE (int_attr);
+
+      if (intr_vector != NULL_TREE)
+	{
+	  char buf[101];
+
+	  intr_vector = TREE_VALUE (intr_vector);
+
+	  /* The interrupt attribute has a vector value.  Turn this into a
+	     section name, switch to that section and put the address of
+	     the current function into that vector slot.  Note msp430_attr()
+	     has already verified the vector name for us.  */
+	  if (TREE_CODE (intr_vector) == STRING_CST)
+	    sprintf (buf, "__interrupt_vector_%.80s",
+		     TREE_STRING_POINTER (intr_vector));
+	  else /* TREE_CODE (intr_vector) == INTEGER_CST */
+	    sprintf (buf, "__interrupt_vector_%u",
+		     (unsigned int) TREE_INT_CST_LOW (intr_vector));
+
+	  switch_to_section (get_section (buf, SECTION_CODE, decl));
+	  fputs ("\t.word\t", file);
+	  assemble_name (file, name);
+	  fputc ('\n', file);
+	  fputc ('\t', file);
+	}
+    }
+
+  switch_to_section (function_section (decl));
+  ASM_OUTPUT_FUNCTION_LABEL (file, name, decl);
+}
+
+static section *
+msp430_function_section (tree decl, enum node_frequency freq, bool startup, bool exit)
+{
+  /* In large mode we must make sure that interrupt handlers are put into
+     low memory as the vector table only accepts 16-bit addresses.  */
+  if (TARGET_LARGE
+      && lookup_attribute ("interrupt", DECL_ATTRIBUTES (decl)))
+    return get_section (".lowtext", SECTION_CODE | SECTION_WRITE , decl);
+
+  /* Otherwise, use the default function section.  */
+  return default_function_section (decl, freq, startup, exit);
+}
+
+#undef  TARGET_ASM_FUNCTION_SECTION
+#define TARGET_ASM_FUNCTION_SECTION msp430_function_section
+
+enum msp430_builtin
+{
+  MSP430_BUILTIN_BIC_SR,
+  MSP430_BUILTIN_BIS_SR,
+  MSP430_BUILTIN_max
+};
+
+static GTY(()) tree msp430_builtins [(int) MSP430_BUILTIN_max];
+
+static void
+msp430_init_builtins (void)
+{
+  tree void_ftype_int = build_function_type_list (void_type_node, integer_type_node, NULL);
+
+  msp430_builtins[MSP430_BUILTIN_BIC_SR] =
+    add_builtin_function ( "__bic_SR_register_on_exit", void_ftype_int,
+			   MSP430_BUILTIN_BIC_SR, BUILT_IN_MD, NULL, NULL_TREE);
+
+  msp430_builtins[MSP430_BUILTIN_BIS_SR] =
+    add_builtin_function ( "__bis_SR_register_on_exit", void_ftype_int,
+			   MSP430_BUILTIN_BIS_SR, BUILT_IN_MD, NULL, NULL_TREE);
+}
+
+static tree
+msp430_builtin_decl (unsigned code, bool initialize ATTRIBUTE_UNUSED)
+{
+  switch (code)
+    {
+    case MSP430_BUILTIN_BIC_SR:
+    case MSP430_BUILTIN_BIS_SR:
+      return msp430_builtins[code];
+    default:
+      return error_mark_node;
+    }
+}
+
+static rtx
+msp430_expand_builtin (tree exp,
+		       rtx target ATTRIBUTE_UNUSED,
+		       rtx subtarget ATTRIBUTE_UNUSED,
+		       enum machine_mode mode ATTRIBUTE_UNUSED,
+		       int ignore ATTRIBUTE_UNUSED)
+{
+  tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0);
+  unsigned int fcode = DECL_FUNCTION_CODE (fndecl);
+  rtx arg1 = expand_normal (CALL_EXPR_ARG (exp, 0));
+
+  if (! msp430_is_interrupt_func ())
+    {
+      error ("MSP430 builtin functions only work inside interrupt handlers");
+      return NULL_RTX;
+    }
+
+  if (! REG_P (arg1) && ! CONSTANT_P (arg1))
+    arg1 = force_reg (mode, arg1);
+
+  switch (fcode)
+    {
+    case MSP430_BUILTIN_BIC_SR:  emit_insn (gen_bic_SR (arg1)); break;
+    case MSP430_BUILTIN_BIS_SR:  emit_insn (gen_bis_SR (arg1)); break;
+    default:
+      internal_error ("bad builtin code");
+      break;
+    }
+  return NULL_RTX;
+}
+
+#undef  TARGET_INIT_BUILTINS
+#define TARGET_INIT_BUILTINS  msp430_init_builtins
+
+#undef  TARGET_EXPAND_BUILTIN
+#define TARGET_EXPAND_BUILTIN msp430_expand_builtin
+
+#undef  TARGET_BUILTIN_DECL
+#define TARGET_BUILTIN_DECL   msp430_builtin_decl
+
 void
 msp430_expand_prologue (void)
 {
@@ -911,8 +1176,19 @@ msp430_expand_prologue (void)
   rtx sp = stack_pointer_rtx;
   rtx p;
 
+  if (is_naked_func ())
+    return;
+
   emit_insn (gen_prologue_start_marker ());
 
+  if (is_critical_func ())
+    {
+      emit_insn (gen_push_intr_state ());
+      emit_insn (gen_disable_interrupts ());
+    }
+  else if (is_reentrant_func ())
+    emit_insn (gen_disable_interrupts ());
+
   if (!cfun->machine->computed)
     msp430_compute_frame_info ();
 
@@ -1009,6 +1285,9 @@ msp430_expand_epilogue (int is_eh)
   int fs;
   int helper_n = 0;
 
+  if (is_naked_func ())
+    return;
+
   if (cfun->machine->need_to_save [10])
     {
       /* Check for a helper function.  */
@@ -1070,6 +1349,9 @@ msp430_expand_epilogue (int is_eh)
 	    i += count - 1;
 	  }
 	else if (i == 11 - helper_n
+		 && ! msp430_is_interrupt_func ()
+		 && ! is_reentrant_func ()
+		 && ! is_critical_func ()
 		 && crtl->args.pretend_args_size == 0
 		 /* Calling the helper takes as many bytes as the POP;RET sequence.  */
 		 && helper_n != 1
@@ -1092,7 +1374,12 @@ msp430_expand_epilogue (int is_eh)
 
   if (crtl->args.pretend_args_size)
     emit_insn (gen_swap_and_shrink ());
-    
+
+  if (is_critical_func ())
+    emit_insn (gen_pop_intr_state ());
+  else if (is_reentrant_func ())
+    emit_insn (gen_enable_interrupts ());
+
   emit_jump_insn (gen_msp_return ());
 }
 
@@ -1131,12 +1418,15 @@ msp430_expand_eh_return (rtx eh_handler)
 }
 
 /* This is a list of MD patterns that implement fixed-count shifts.  */
-static struct {
+static struct
+{
   const char *name;
   int count;
   int need_430x;
   rtx (*genfunc)(rtx,rtx);
-} const_shift_helpers[] = {
+}
+  const_shift_helpers[] =
+{
 #define CSH(N,C,X,G) { "__mspabi_"N, C, X, gen_##G }
 
   CSH ("slli", 1, 1, slli_1),
@@ -1329,7 +1619,6 @@ msp430_split_movsi (rtx *operands)
 }
 
 
-
 /* The MSPABI specifies the names of various helper functions, many of
    which are compatible with GCC's helpers.  This table maps the GCC
    name to the MSPABI name.  */
@@ -1600,6 +1889,15 @@ msp430_print_operand (FILE * file, rtx op, int letter)
       if (TARGET_LARGE)
 	fprintf (file, "A");
       return;
+
+    case 'O':
+      /* Computes the offset to the top of the stack for the current frame.
+	 This has to be done here rather than in, say, msp430_expand_builtin()
+	 because builtins are expanded before the frame layout is determined.  */
+      fprintf (file, "%d",
+	       msp430_initial_elimination_offset (ARG_POINTER_REGNUM, STACK_POINTER_REGNUM)
+	        - 2);
+      return ;
     }
 
   switch (GET_CODE (op))
diff --git a/gcc/config/msp430/msp430.h b/gcc/config/msp430/msp430.h
index bf3b15c..0b77c4a 100644
--- a/gcc/config/msp430/msp430.h
+++ b/gcc/config/msp430/msp430.h
@@ -1,5 +1,5 @@
 /* GCC backend definitions for the TI MSP430 Processor
-   Copyright (C) 2012 Free Software Foundation, Inc.
+   Copyright (C) 2012-2013 Free Software Foundation, Inc.
    Contributed by Red Hat.
 
    This file is part of GCC.
@@ -29,6 +29,7 @@ extern bool msp430x;
 #define TARGET_CPU_CPP_BUILTINS()               \
   do                                            \
     {                                           \
+      builtin_define ("NO_TRAMPOLINES");        \
       builtin_define ("__MSP430__"); 		\
       if (msp430x)				\
 	{					\
@@ -281,7 +282,8 @@ enum reg_class
 
 
 
-typedef struct {
+typedef struct
+{
   /* These two are the current argument status.  */
   char reg_used[4];
 #define CA_FIRST_REG 12
diff --git a/gcc/config/msp430/msp430.md b/gcc/config/msp430/msp430.md
index 4324503..a258867 100644
--- a/gcc/config/msp430/msp430.md
+++ b/gcc/config/msp430/msp430.md
@@ -38,6 +38,13 @@
 
    UNS_GROW_AND_SWAP
    UNS_SWAP_AND_SHRINK
+   
+   UNS_DINT
+   UNS_EINT
+   UNS_PUSH_INTR
+   UNS_POP_INTR
+   UNS_BIC_SR
+   UNS_BIS_SR
   ])
   
 (include "predicates.md")
@@ -78,7 +85,7 @@
 
 (define_insn "pushm"
   [(unspec_volatile [(match_operand 0 "register_operand" "r")
-		     (match_operand 1 "immediate_operand" "i")] UNS_PUSHM)]
+		     (match_operand 1 "immediate_operand" "n")] UNS_PUSHM)]
   ""
   "PUSHM%B0\t%1, %0"
   )
@@ -950,7 +957,7 @@
 (define_insn "msp_return"
   [(return)]
   ""
-  { return TARGET_LARGE ? "RETA" : "RET"; }
+  { return msp430_is_interrupt_func () ? "RETI" : (TARGET_LARGE ? "RETA" : "RET"); }
 )
 
 ;; This pattern is NOT, as expected, a return pattern.  It's called
@@ -1102,7 +1109,6 @@
    CMP%X0.W\t%1, %2 { J%R0\t%l3"
   )
 
-
 (define_insn "*bitbranch<mode>4"
   [(set (pc) (if_then_else
 	      (ne (and:QHI (match_operand:QHI 0 "msp_nonimmediate_operand" "rYs,rm")
@@ -1158,7 +1164,7 @@
   )
 
 ;;------------------------------------------------------------
-;; zero-extend versions of the above
+;; zero-extract versions of the above
 
 (define_insn "*bitbranch<mode>4_z"
   [(set (pc) (if_then_else
@@ -1227,3 +1233,42 @@
   "NOP"
 )
   
+(define_insn "disable_interrupts"
+  [(unspec_volatile [(const_int 0)] UNS_DINT)]
+  ""
+  "DINT"
+  )
+
+(define_insn "enable_interrupts"
+  [(unspec_volatile [(const_int 0)] UNS_EINT)]
+  ""
+  "EINT"
+  )
+
+(define_insn "push_intr_state"
+  [(unspec_volatile [(const_int 0)] UNS_PUSH_INTR)]
+  ""
+  "PUSH\tSR"
+  )
+
+(define_insn "pop_intr_state"
+  [(unspec_volatile [(const_int 0)] UNS_POP_INTR)]
+  ""
+  "POP\tSR"
+  )
+
+;; Clear bits in the copy of the status register that is currently
+;; saved on the stack at the top of the interrupt handler.
+(define_insn "bic_SR"
+  [(unspec_volatile [(match_operand 0 "nonmemory_operand" "ir")] UNS_BIC_SR)]
+  ""
+  "BIC.W\t%0, %O0(SP)"
+  )
+
+;; Set bits in the copy of the status register that is currently
+;; saved on the stack at the top of the interrupt handler.
+(define_insn "bis_SR"
+  [(unspec_volatile [(match_operand 0 "nonmemory_operand" "ir")] UNS_BIS_SR)]
+  ""
+  "BIS.W\t%0, %O0(SP)"
+  )