[PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[Christian Bruel]

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Implements and document the hooks to support target_attributes.

The emission of blx is handled directly for armv5 to overcome a bug with
the current binutils that fails with calls to a static symbol in a
different section. (e.g .text -> .text.startup) in different modes.

(ref https://sourceware.org/bugzilla/show_bug.cgi?id=17505)

Regtests included

Thanks

Christian


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2014-09-23  Christian Bruel  <christian.bruel@st.com>

	* config/arm/arm.opt (THUMB, arm_restrict_it, inline_asm_unified): Save.
	* config/arm/arm.h (arm_valid_target_attribute_tree): Declare.
	(arm_reset_previous_fndecl, arm_change_mode_p): Likewise.
	(SWITCHABLE_TARGET): Define.
	* config/arm/arm.c (arm_reset_previous_fndecl): New functions.
	(arm_valid_target_attribute_tree, arm_change_mode_p): Likewise.
	(arm_valid_target_attribute_p): Likewise.
	(arm_set_current_function, arm_can_inline_p): Likewise.
	(arm_valid_target_attribute_rec): Likewise.
	(arm_previous_fndecl): New variable.
	(TARGET_SET_CURRENT_FUNCTION, TARGET_OPTION_VALID_ATTRIBUTE_P): Define.
	(TARGET_CAN_INLINE_P): Define.
	(arm_asm_trampoline_template): Emit mode.
	(arm_file_start): Don't set unified syntax.
	(arm_declare_function_name): Set unified syntax and mode.
	(arm_option_override): Init target_option_default_node.
	and target_option_current_node.
	* config/arm/arm.md (*call_value_symbol): Set mode when possible.
	(*call_symbol): Likewise.
	* doc/extend.texi: Document ARM target and pragma attribute.
	* doc/invoke.texi: Likewise.

diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.c gnu_trunk.p4/gcc/gcc/config/arm/arm.c
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.c	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.c	2015-05-06 15:03:29.393992051 +0200
@@ -94,6 +94,7 @@
 #include "opts.h"
 #include "dumpfile.h"
 #include "gimple-expr.h"
+#include "target-globals.h"
 #include "builtins.h"
 #include "tm-constrs.h"
 #include "rtl-iter.h"
@@ -264,6 +265,9 @@
 static void arm_expand_builtin_va_start (tree, rtx);
 static tree arm_gimplify_va_arg_expr (tree, tree, gimple_seq *, gimple_seq *);
 static void arm_option_override (void);
+static void arm_set_current_function (tree);
+static bool arm_can_inline_p (tree, tree);
+static bool arm_valid_target_attribute_p (tree, tree, tree, int);
 static unsigned HOST_WIDE_INT arm_shift_truncation_mask (machine_mode);
 static bool arm_macro_fusion_p (void);
 static bool arm_cannot_copy_insn_p (rtx_insn *);
@@ -412,6 +416,9 @@
 #undef  TARGET_ASM_FUNCTION_EPILOGUE
 #define TARGET_ASM_FUNCTION_EPILOGUE arm_output_function_epilogue
 
+#undef TARGET_CAN_INLINE_P
+#define TARGET_CAN_INLINE_P arm_can_inline_p
+
 #undef  TARGET_OPTION_OVERRIDE
 #define TARGET_OPTION_OVERRIDE arm_option_override
 
@@ -430,6 +437,12 @@
 #undef  TARGET_SCHED_ADJUST_COST
 #define TARGET_SCHED_ADJUST_COST arm_adjust_cost
 
+#undef TARGET_SET_CURRENT_FUNCTION
+#define TARGET_SET_CURRENT_FUNCTION arm_set_current_function
+
+#undef TARGET_OPTION_VALID_ATTRIBUTE_P
+#define TARGET_OPTION_VALID_ATTRIBUTE_P arm_valid_target_attribute_p
+
 #undef TARGET_SCHED_REORDER
 #define TARGET_SCHED_REORDER arm_sched_reorder
 
@@ -2750,6 +2763,9 @@
     }
 }
 
+/* Options after initial target override.  */
+static GTY(()) tree init_optimize;
+
 /* Reset options between modes that the user has specified.  */
 static void
 arm_option_override_internal (struct gcc_options *opts,
@@ -2772,6 +2788,10 @@
   if (TREE_TARGET_THUMB (opts) && TARGET_CALLEE_INTERWORKING)
     opts->x_target_flags |= MASK_INTERWORK;
 
+  /* need to remember initial values so combinaisons of options like
+     -mflip-thumb -mthumb -fno-schedule-insns work for any attribute.  */
+  cl_optimization *to = TREE_OPTIMIZATION (init_optimize);
+
   if (! opts_set->x_arm_restrict_it)
     opts->x_arm_restrict_it = arm_arch8;
 
@@ -2779,15 +2799,17 @@
     opts->x_arm_restrict_it = 0;
 
   if (TREE_TARGET_THUMB1 (opts))
-    {
-      /* Don't warn since it's on by default in -O2.  */
-      opts->x_flag_schedule_insns = 0;
-    }
+    /* Don't warn since it's on by default in -O2.  */
+    opts->x_flag_schedule_insns = 0;
+  else
+    opts->x_flag_schedule_insns = to->x_flag_schedule_insns;
 
   /* Disable shrink-wrap when optimizing function for size, since it tends to
      generate additional returns.  */
   if (optimize_function_for_size_p (cfun) && TREE_TARGET_THUMB2 (opts))
     opts->x_flag_shrink_wrap = false;
+  else
+    opts->x_flag_shrink_wrap = to->x_flag_shrink_wrap;
 
   /* In Thumb1 mode, we emit the epilogue in RTL, but the last insn
      - epilogue_insns - does not accurately model the corresponding insns
@@ -2799,6 +2821,8 @@
      fipa-ra.  */
   if (TREE_TARGET_THUMB1 (opts))
     opts->x_flag_ipa_ra = 0;
+  else
+    opts->x_flag_ipa_ra = to->x_flag_ipa_ra;
 
   /* Thumb2 inline assembly code should always use unified syntax.
      This will apply to ARM and Thumb1 eventually.  */
@@ -3291,12 +3315,20 @@
       && (!arm_arch7 || !current_tune->prefer_ldrd_strd))
     flag_schedule_fusion = 0;
 
+  /* Need to remember initial options before they are overriden.  */
+  init_optimize = build_optimization_node (&global_options);
+
   arm_option_override_internal (&global_options, &global_options_set);
   arm_option_check_internal (&global_options);
   arm_option_params_internal (&global_options);
 
   /* Register global variables with the garbage collector.  */
   arm_add_gc_roots ();
+
+  /* Save the initial options in case the user does function specific
+     options.  */
+  target_option_default_node = target_option_current_node
+    = build_target_option_node (&global_options);
 }
 
 static void
@@ -3450,13 +3482,20 @@
 static void
 arm_asm_trampoline_template (FILE *f)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (f, "\t.syntax unified\n");
+  else
+    fprintf (f, "\t.syntax divided\n");
+
   if (TARGET_ARM)
     {
+      fprintf (f, "\t.arm\n");
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", STATIC_CHAIN_REGNUM, PC_REGNUM);
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", PC_REGNUM, PC_REGNUM);
     }
   else if (TARGET_THUMB2)
     {
+      fprintf (f, "\t.thumb\n");
       /* The Thumb-2 trampoline is similar to the arm implementation.
 	 Unlike 16-bit Thumb, we enter the stub in thumb mode.  */
       asm_fprintf (f, "\tldr.w\t%r, [%r, #4]\n",
@@ -23903,6 +23942,23 @@
   return 0;
 }
 
+/* Check that FUNC is called with a different mode.  */
+
+bool
+arm_change_mode_p (tree func)
+{
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    return false;
+
+  tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (func);
+
+  if (!callee_tree)
+    callee_tree = target_option_default_node;
+
+  struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
+
+  return (TREE_TARGET_THUMB (callee_opts) != TARGET_THUMB);
+}
 
 /* Given the stack offsets and register mask in OFFSETS, decide how
    many additional registers to push instead of subtracting a constant
@@ -25518,9 +25574,6 @@
 {
   int val;
 
-  if (TARGET_UNIFIED_ASM)
-    asm_fprintf (asm_out_file, "\t.syntax unified\n");
-
   if (TARGET_BPABI)
     {
       const char *fpu_name;
@@ -29271,9 +29324,196 @@
 	  && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)));
 }
 
+/* Remember the last target of arm_set_current_function.  */
+static GTY(()) tree arm_previous_fndecl;
+
+/* Invalidate arm_previous_fndecl.  */
+void
+arm_reset_previous_fndecl (void)
+{
+  arm_previous_fndecl = NULL_TREE;
+}
+
+/* Establish appropriate back-end context for processing the function
+   FNDECL.  The argument might be NULL to indicate processing at top
+   level, outside of any function scope.  */
+static void
+arm_set_current_function (tree fndecl)
+{
+  if (!fndecl || fndecl == arm_previous_fndecl)
+    return;
+
+  tree old_tree = (arm_previous_fndecl
+		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
+		   : NULL_TREE);
+
+  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
+
+  arm_previous_fndecl = fndecl;
+  if (old_tree == new_tree)
+    ;
+
+  else if (new_tree)
+    {
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  else if (old_tree)
+    {
+      new_tree = target_option_current_node;
+
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else if (new_tree == target_option_default_node)
+	restore_target_globals (&default_target_globals);
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  arm_option_params_internal (&global_options);
+}
+
+/* Hook to determine if one function can safely inline another.  */
+
+static bool
+arm_can_inline_p (tree caller ATTRIBUTE_UNUSED, tree callee ATTRIBUTE_UNUSED)
+{
+  /* Overidde default hook: Always OK to inline between different modes. 
+     Function with mode specific instructions, e.g using asm, must be explicitely 
+     protected with noinline.  */
+  return true;
+}
+
+/* Inner function to process the attribute((target(...))), take an argument and
+   set the current options from the argument.  If we have a list, recursively
+   go over the list.  */
+
+static bool
+arm_valid_target_attribute_rec (tree args,  struct gcc_options *opts)
+{
+  if (TREE_CODE (args) == TREE_LIST)
+    {
+      bool ret = true;
+      for (; args; args = TREE_CHAIN (args))
+	if (TREE_VALUE (args)
+	    && !arm_valid_target_attribute_rec (TREE_VALUE (args), opts))
+	  ret = false;
+      return ret;
+    }
+
+  else if (TREE_CODE (args) != STRING_CST)
+    {
+      error ("attribute %<target%> argument not a string");
+      return false;
+    }
+
+  char *argstr = ASTRDUP (TREE_STRING_POINTER (args));
+  while (argstr && *argstr != '\0')
+    {
+      while (ISSPACE (*argstr))
+	argstr++;
+
+      if (!strcmp (argstr, "thumb"))
+	{
+	  opts->x_target_flags |= MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      if (!strcmp (argstr, "arm"))
+	{
+	  opts->x_target_flags &= ~MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      warning (0, "attribute(target(\"%s\")) is unknown", argstr);
+      return false;
+    }
+
+  return false;
+}
+
+/* Return a TARGET_OPTION_NODE tree of the target options listed or NULL.  */
+
+tree
+arm_valid_target_attribute_tree (tree args, struct gcc_options *opts,
+				 struct gcc_options *opts_set)
+{
+  if (!arm_valid_target_attribute_rec (args, opts))
+    return NULL_TREE;
+
+  /* Do any overrides, such as global options arch=xxx.  */
+  arm_option_override_internal (opts, opts_set);
+
+  return build_target_option_node (opts);
+}
+
+/* Hook to validate attribute((target("string"))).  */
+
+static bool
+arm_valid_target_attribute_p (tree fndecl, tree ARG_UNUSED (name),
+			      tree args, int ARG_UNUSED (flags))
+{
+  bool ret = true;
+  struct gcc_options func_options;
+  tree cur_tree, new_optimize;
+  gcc_assert ((fndecl != NULL_TREE) && (args != NULL_TREE));
+
+  /* Get the optimization options of the current function.  */
+  tree func_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl);
+
+  /* If the function changed the optimization levels as well as setting target
+     options, start with the optimizations specified.  */
+  if (!func_optimize)
+    func_optimize = optimization_default_node;
+
+  /* Init func_options.  */
+  memset (&func_options, 0, sizeof (func_options));
+  init_options_struct (&func_options, NULL);
+  lang_hooks.init_options_struct (&func_options);
+
+  /* Initialize func_options to the defaults.  */
+  cl_optimization_restore (&func_options,
+			   TREE_OPTIMIZATION (func_optimize));
+
+  cl_target_option_restore (&func_options,
+			    TREE_TARGET_OPTION (target_option_default_node));
+
+  /* Set func_options flags with new target mode.  */
+  cur_tree = arm_valid_target_attribute_tree (args, &func_options,
+					      &global_options_set);
+
+  if (cur_tree == NULL_TREE)
+    ret = false;
+
+  new_optimize = build_optimization_node (&func_options);
+
+  DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = cur_tree;
+
+  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl) = new_optimize;
+
+  return ret;
+}
+
 void
 arm_declare_function_name (FILE *stream, const char *name, tree decl)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (stream, "\t.syntax unified\n");
+  else
+    fprintf (stream, "\t.syntax divided\n");
+
   if (TARGET_THUMB)
     {
       if (is_called_in_ARM_mode (decl)
@@ -29285,6 +29525,8 @@
       else
 	fprintf (stream, "\t.thumb\n\t.thumb_func\n");
     }
+  else
+    fprintf (stream, "\t.arm\n");
 
   if (TARGET_POKE_FUNCTION_NAME)
     arm_poke_function_name (stream, (const char *) name);
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.h gnu_trunk.p4/gcc/gcc/config/arm/arm.h
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.h	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.h	2015-05-06 14:36:32.227213416 +0200
@@ -2332,4 +2332,8 @@
 
 #define DRIVER_SELF_SPECS MCPU_MTUNE_NATIVE_SPECS
 #define TARGET_SUPPORTS_WIDE_INT 1
+
+/* For switching between functions with different target attributes.  */
+#define SWITCHABLE_TARGET 1
+
 #endif /* ! GCC_ARM_H */
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.md gnu_trunk.p4/gcc/gcc/config/arm/arm.md
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.md	2015-05-06 14:31:40.678713158 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.md	2015-05-06 14:36:32.231213422 +0200
@@ -7722,6 +7722,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[0]))"
   "*
   {
+   rtx op = operands[0];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a0(PLT)\" : \"bl%?\\t%a0\";
   }"
   [(set_attr "type" "call")]
@@ -7739,6 +7746,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[1]))"
   "*
   {
+   rtx op = operands[1];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a1(PLT)\" : \"bl%?\\t%a1\";
   }"
   [(set_attr "type" "call")]
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.opt gnu_trunk.p4/gcc/gcc/config/arm/arm.opt
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.opt	2015-03-30 10:44:52.901327167 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.opt	2015-05-06 14:36:32.231213422 +0200
@@ -182,7 +182,7 @@
 Specify the minimum bit alignment of structures
 
 mthumb
-Target Report RejectNegative Mask(THUMB)
+Target Report RejectNegative Mask(THUMB) Save
 Generate code for Thumb state
 
 mthumb-interwork
@@ -246,7 +246,7 @@
 Only generate absolute relocations on word sized values.
 
 mrestrict-it
-Target Report Var(arm_restrict_it) Init(2)
+Target Report Var(arm_restrict_it) Init(2) Save
 Generate IT blocks appropriate for ARMv8.
 
 mold-rtx-costs
@@ -275,5 +275,5 @@
 Assume loading data from flash is slower than fetching instructions.
 
 masm-syntax-unified
-Target Report Var(inline_asm_unified) Init(0)
+Target Report Var(inline_asm_unified) Init(0) Save
 Assume unified syntax for Thumb inline assembly code.
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm-protos.h gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h
--- gnu_trunk.p3/gcc/gcc/config/arm/arm-protos.h	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h	2015-05-06 14:36:32.231213422 +0200
@@ -210,6 +210,9 @@
 extern int arm_dllimport_p (tree);
 extern void arm_mark_dllexport (tree);
 extern void arm_mark_dllimport (tree);
+extern bool arm_change_mode_p (tree);
+extern tree arm_valid_target_attribute_tree (tree, struct gcc_options *,
+					     struct gcc_options *);
 #endif
 
 extern void arm_pr_long_calls (struct cpp_reader *);
@@ -317,6 +320,8 @@
 
 extern void arm_emit_eabi_attribute (const char *, int, int);
 
+extern void arm_reset_previous_fndecl (void);
+
 /* Defined in gcc/common/config/arm-common.c.  */
 extern const char *arm_rewrite_selected_cpu (const char *name);
 
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/extend.texi gnu_trunk.p4/gcc/gcc/doc/extend.texi
--- gnu_trunk.p3/gcc/gcc/doc/extend.texi	2015-05-06 09:00:31.232943164 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/extend.texi	2015-05-06 14:50:05.632612233 +0200
@@ -3419,6 +3419,25 @@
 the compiler rejects attempts to specify an alternative.
 @end table
 
+@item target (@var{options})
+@cindex @code{target} function attribute
+As discussed in @ref{Common Function Attributes}, this attribute 
+allows specification of target-specific compilation options.
+
+On ARM, the following options are allowed:
+
+@table @samp
+@item thumb
+@cindex @code{target("thumb")} function attribute, ARM
+Force Thumb1 Thumb2 code generation depending on the architecture.
+
+@item arm
+@cindex @code{target("arm")} function attribute, ARM
+Force ARM code generation.
+@end table
+
+Functions from different modes can be inlined using the caller mode.
+
 @node AVR Function Attributes
 @subsection AVR Function Attributes
 
@@ -18436,8 +18455,9 @@
 @xref{Function Attributes}, for more information about the
 @code{target} attribute and the attribute syntax.
 
-The @code{#pragma GCC target} pragma is presently implemented for
-x86, PowerPC, and Nios II targets only.
+The @code{#pragma GCC target} pragma is implemented for
+ARM, x86, PowerPC, and Nios II targets.
+
 @end table
 
 @table @code
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/invoke.texi gnu_trunk.p4/gcc/gcc/doc/invoke.texi
--- gnu_trunk.p3/gcc/gcc/doc/invoke.texi	2015-05-06 09:00:31.232943164 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/invoke.texi	2015-05-06 14:36:32.331213593 +0200
@@ -13434,6 +13434,10 @@
 configuring GCC with the @option{--with-mode=}@var{state}
 configure option.
 
+You can also override the ARM and Thumb mode for each function
+by using the @code{target("thumb")} and @code{target("arm")} function attributes
+(@pxref{Function Attributes}) or pragmas (@pxref{Function Specific Option Pragmas}).
+
 @item -mtpcs-frame
 @opindex mtpcs-frame
 Generate a stack frame that is compliant with the Thumb Procedure Call
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is recogniwed.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".arm" } } */
+/* { dg-final { scan-assembler-not "ite" } } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is rejected for M profile.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv6-m" } } */
+/* { dg-add-options arm_arch_v6m } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{  /* { dg-error "does not support" } */
+  return a ? 1 : 5;
+}
+
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target thumb is recogniwed. */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".thumb" } } */
+/* { dg-final { scan-assembler "ite" } } */
+
+int __attribute__((target("thumb")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,24 @@
+/* Check that a change mode to a static function is correctly handled. */
+/* { dg-do run } */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+static void
+ __attribute__((__noinline__)) 
+foo (void)
+{
+  __asm__ ("");
+}
+
+static void
+__attribute__((__noinline__)) 
+__attribute__((target("thumb")))
+bar (void)
+{
+  __asm__ ("");
+}
+
+int main()
+{
+  foo();
+  bar();
+}

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[Sandra Loosemore]

On 05/06/2015 08:24 AM, Christian Bruel wrote:
> diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/extend.texi gnu_trunk.p4/gcc/gcc/doc/extend.texi
> --- gnu_trunk.p3/gcc/gcc/doc/extend.texi	2015-05-06 09:00:31.232943164 +0200
> +++ gnu_trunk.p4/gcc/gcc/doc/extend.texi	2015-05-06 14:50:05.632612233 +0200
> @@ -3419,6 +3419,25 @@
>  the compiler rejects attempts to specify an alternative.
>  @end table
>
> +@item target (@var{options})
> +@cindex @code{target} function attribute
> +As discussed in @ref{Common Function Attributes}, this attribute
> +allows specification of target-specific compilation options.
> +
> +On ARM, the following options are allowed:
> +
> +@table @samp
> +@item thumb
> +@cindex @code{target("thumb")} function attribute, ARM
> +Force Thumb1 Thumb2 code generation depending on the architecture.

"Force Thumb or Thumb-2 code generation, depending on the architecture."

(I believe that's ARM's official terminology, rather than "Thumb1" or 
"Thumb2".)

> +
> +@item arm
> +@cindex @code{target("arm")} function attribute, ARM
> +Force ARM code generation.
> +@end table
> +
> +Functions from different modes can be inlined using the caller mode.

"...the caller's mode."

> +
>  @node AVR Function Attributes
>  @subsection AVR Function Attributes
>
> @@ -18436,8 +18455,9 @@
>  @xref{Function Attributes}, for more information about the
>  @code{target} attribute and the attribute syntax.
>
> -The @code{#pragma GCC target} pragma is presently implemented for
> -x86, PowerPC, and Nios II targets only.
> +The @code{#pragma GCC target} pragma is implemented for
> +ARM, x86, PowerPC, and Nios II targets.
> +
>  @end table
>
>  @table @code

Please also add a cross-reference to ARM Function Attributes in the main 
entry for @item target in Common Function Attributes, in this paragraph:

The options supported are specific to each target; refer to @ref{x86
Function Attributes}, @ref{PowerPC Function Attributes}, and
@ref{Nios II Function Attributes}, for details.

> diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/invoke.texi gnu_trunk.p4/gcc/gcc/doc/invoke.texi
> --- gnu_trunk.p3/gcc/gcc/doc/invoke.texi	2015-05-06 09:00:31.232943164 +0200
> +++ gnu_trunk.p4/gcc/gcc/doc/invoke.texi	2015-05-06 14:36:32.331213593 +0200
> @@ -13434,6 +13434,10 @@
>  configuring GCC with the @option{--with-mode=}@var{state}
>  configure option.
>
> +You can also override the ARM and Thumb mode for each function
> +by using the @code{target("thumb")} and @code{target("arm")} function attributes
> +(@pxref{Function Attributes}) or pragmas (@pxref{Function Specific Option Pragmas}).

You can make the first reference point at the ARM Function Attributes 
node, now that it exists, instead of the generic Function Attributes 
section.

> +
>  @item -mtpcs-frame
>  @opindex mtpcs-frame
>  Generate a stack frame that is compliant with the Thumb Procedure Call

-Sandra

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[Christian Bruel]

[-- Attachment #1: Type: text/plain, Size: 523 bytes --]

+ Sandra's doc review fixes.

tested with make doc pdf

thanks

Christian

On 05/06/2015 04:24 PM, Christian Bruel wrote:
> Implements and document the hooks to support target_attributes.
> 
> The emission of blx is handled directly for armv5 to overcome a bug with
> the current binutils that fails with calls to a static symbol in a
> different section. (e.g .text -> .text.startup) in different modes.
> 
> (ref https://sourceware.org/bugzilla/show_bug.cgi?id=17505)
> 
> Regtests included
> 
> Thanks
> 
> Christian
> 

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: p4.patch --]
[-- Type: text/x-patch; name="p4.patch", Size: 22542 bytes --]

2014-09-23  Christian Bruel  <christian.bruel@st.com>

	* config/arm/arm.opt (THUMB, arm_restrict_it, inline_asm_unified): Save.
	* config/arm/arm.h (arm_valid_target_attribute_tree): Declare.
	(arm_reset_previous_fndecl, arm_change_mode_p): Likewise.
	(SWITCHABLE_TARGET): Define.
	* config/arm/arm.c (arm_reset_previous_fndecl): New functions.
	(arm_valid_target_attribute_tree, arm_change_mode_p): Likewise.
	(arm_valid_target_attribute_p): Likewise.
	(arm_set_current_function, arm_can_inline_p): Likewise.
	(arm_valid_target_attribute_rec): Likewise.
	(arm_previous_fndecl): New variable.
	(TARGET_SET_CURRENT_FUNCTION, TARGET_OPTION_VALID_ATTRIBUTE_P): Define.
	(TARGET_CAN_INLINE_P): Define.
	(arm_asm_trampoline_template): Emit mode.
	(arm_file_start): Don't set unified syntax.
	(arm_declare_function_name): Set unified syntax and mode.
	(arm_option_override): Init target_option_default_node.
	and target_option_current_node.
	* config/arm/arm.md (*call_value_symbol): Set mode when possible.
	(*call_symbol): Likewise.
	* doc/extend.texi: Document ARM target and pragma attribute.
	* doc/invoke.texi: Likewise.

2014-09-23  Christian Bruel  <christian.bruel@st.com>

	* gcc.target/arm/attr_arm.c: New test
	* gcc.target/arm/attr_arm-err.c: New test
	* gcc.target/arm/attr_thumb.c: New test
	* gcc.target/arm/attr_thumb-static.c: New test



diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.c gnu_trunk.p4/gcc/gcc/config/arm/arm.c
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.c	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.c	2015-05-06 15:03:29.393992051 +0200
@@ -94,6 +94,7 @@
 #include "opts.h"
 #include "dumpfile.h"
 #include "gimple-expr.h"
+#include "target-globals.h"
 #include "builtins.h"
 #include "tm-constrs.h"
 #include "rtl-iter.h"
@@ -264,6 +265,9 @@
 static void arm_expand_builtin_va_start (tree, rtx);
 static tree arm_gimplify_va_arg_expr (tree, tree, gimple_seq *, gimple_seq *);
 static void arm_option_override (void);
+static void arm_set_current_function (tree);
+static bool arm_can_inline_p (tree, tree);
+static bool arm_valid_target_attribute_p (tree, tree, tree, int);
 static unsigned HOST_WIDE_INT arm_shift_truncation_mask (machine_mode);
 static bool arm_macro_fusion_p (void);
 static bool arm_cannot_copy_insn_p (rtx_insn *);
@@ -412,6 +416,9 @@
 #undef  TARGET_ASM_FUNCTION_EPILOGUE
 #define TARGET_ASM_FUNCTION_EPILOGUE arm_output_function_epilogue
 
+#undef TARGET_CAN_INLINE_P
+#define TARGET_CAN_INLINE_P arm_can_inline_p
+
 #undef  TARGET_OPTION_OVERRIDE
 #define TARGET_OPTION_OVERRIDE arm_option_override
 
@@ -430,6 +437,12 @@
 #undef  TARGET_SCHED_ADJUST_COST
 #define TARGET_SCHED_ADJUST_COST arm_adjust_cost
 
+#undef TARGET_SET_CURRENT_FUNCTION
+#define TARGET_SET_CURRENT_FUNCTION arm_set_current_function
+
+#undef TARGET_OPTION_VALID_ATTRIBUTE_P
+#define TARGET_OPTION_VALID_ATTRIBUTE_P arm_valid_target_attribute_p
+
 #undef TARGET_SCHED_REORDER
 #define TARGET_SCHED_REORDER arm_sched_reorder
 
@@ -2750,6 +2763,9 @@
     }
 }
 
+/* Options after initial target override.  */
+static GTY(()) tree init_optimize;
+
 /* Reset options between modes that the user has specified.  */
 static void
 arm_option_override_internal (struct gcc_options *opts,
@@ -2772,6 +2788,10 @@
   if (TREE_TARGET_THUMB (opts) && TARGET_CALLEE_INTERWORKING)
     opts->x_target_flags |= MASK_INTERWORK;
 
+  /* need to remember initial values so combinaisons of options like
+     -mflip-thumb -mthumb -fno-schedule-insns work for any attribute.  */
+  cl_optimization *to = TREE_OPTIMIZATION (init_optimize);
+
   if (! opts_set->x_arm_restrict_it)
     opts->x_arm_restrict_it = arm_arch8;
 
@@ -2779,15 +2799,17 @@
     opts->x_arm_restrict_it = 0;
 
   if (TREE_TARGET_THUMB1 (opts))
-    {
-      /* Don't warn since it's on by default in -O2.  */
-      opts->x_flag_schedule_insns = 0;
-    }
+    /* Don't warn since it's on by default in -O2.  */
+    opts->x_flag_schedule_insns = 0;
+  else
+    opts->x_flag_schedule_insns = to->x_flag_schedule_insns;
 
   /* Disable shrink-wrap when optimizing function for size, since it tends to
      generate additional returns.  */
   if (optimize_function_for_size_p (cfun) && TREE_TARGET_THUMB2 (opts))
     opts->x_flag_shrink_wrap = false;
+  else
+    opts->x_flag_shrink_wrap = to->x_flag_shrink_wrap;
 
   /* In Thumb1 mode, we emit the epilogue in RTL, but the last insn
      - epilogue_insns - does not accurately model the corresponding insns
@@ -2799,6 +2821,8 @@
      fipa-ra.  */
   if (TREE_TARGET_THUMB1 (opts))
     opts->x_flag_ipa_ra = 0;
+  else
+    opts->x_flag_ipa_ra = to->x_flag_ipa_ra;
 
   /* Thumb2 inline assembly code should always use unified syntax.
      This will apply to ARM and Thumb1 eventually.  */
@@ -3291,12 +3315,20 @@
       && (!arm_arch7 || !current_tune->prefer_ldrd_strd))
     flag_schedule_fusion = 0;
 
+  /* Need to remember initial options before they are overriden.  */
+  init_optimize = build_optimization_node (&global_options);
+
   arm_option_override_internal (&global_options, &global_options_set);
   arm_option_check_internal (&global_options);
   arm_option_params_internal (&global_options);
 
   /* Register global variables with the garbage collector.  */
   arm_add_gc_roots ();
+
+  /* Save the initial options in case the user does function specific
+     options.  */
+  target_option_default_node = target_option_current_node
+    = build_target_option_node (&global_options);
 }
 
 static void
@@ -3450,13 +3482,20 @@
 static void
 arm_asm_trampoline_template (FILE *f)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (f, "\t.syntax unified\n");
+  else
+    fprintf (f, "\t.syntax divided\n");
+
   if (TARGET_ARM)
     {
+      fprintf (f, "\t.arm\n");
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", STATIC_CHAIN_REGNUM, PC_REGNUM);
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", PC_REGNUM, PC_REGNUM);
     }
   else if (TARGET_THUMB2)
     {
+      fprintf (f, "\t.thumb\n");
       /* The Thumb-2 trampoline is similar to the arm implementation.
 	 Unlike 16-bit Thumb, we enter the stub in thumb mode.  */
       asm_fprintf (f, "\tldr.w\t%r, [%r, #4]\n",
@@ -23903,6 +23942,23 @@
   return 0;
 }
 
+/* Check that FUNC is called with a different mode.  */
+
+bool
+arm_change_mode_p (tree func)
+{
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    return false;
+
+  tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (func);
+
+  if (!callee_tree)
+    callee_tree = target_option_default_node;
+
+  struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
+
+  return (TREE_TARGET_THUMB (callee_opts) != TARGET_THUMB);
+}
 
 /* Given the stack offsets and register mask in OFFSETS, decide how
    many additional registers to push instead of subtracting a constant
@@ -25518,9 +25574,6 @@
 {
   int val;
 
-  if (TARGET_UNIFIED_ASM)
-    asm_fprintf (asm_out_file, "\t.syntax unified\n");
-
   if (TARGET_BPABI)
     {
       const char *fpu_name;
@@ -29271,9 +29324,196 @@
 	  && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)));
 }
 
+/* Remember the last target of arm_set_current_function.  */
+static GTY(()) tree arm_previous_fndecl;
+
+/* Invalidate arm_previous_fndecl.  */
+void
+arm_reset_previous_fndecl (void)
+{
+  arm_previous_fndecl = NULL_TREE;
+}
+
+/* Establish appropriate back-end context for processing the function
+   FNDECL.  The argument might be NULL to indicate processing at top
+   level, outside of any function scope.  */
+static void
+arm_set_current_function (tree fndecl)
+{
+  if (!fndecl || fndecl == arm_previous_fndecl)
+    return;
+
+  tree old_tree = (arm_previous_fndecl
+		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
+		   : NULL_TREE);
+
+  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
+
+  arm_previous_fndecl = fndecl;
+  if (old_tree == new_tree)
+    ;
+
+  else if (new_tree)
+    {
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  else if (old_tree)
+    {
+      new_tree = target_option_current_node;
+
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else if (new_tree == target_option_default_node)
+	restore_target_globals (&default_target_globals);
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  arm_option_params_internal (&global_options);
+}
+
+/* Hook to determine if one function can safely inline another.  */
+
+static bool
+arm_can_inline_p (tree caller ATTRIBUTE_UNUSED, tree callee ATTRIBUTE_UNUSED)
+{
+  /* Overidde default hook: Always OK to inline between different modes. 
+     Function with mode specific instructions, e.g using asm, must be explicitely 
+     protected with noinline.  */
+  return true;
+}
+
+/* Inner function to process the attribute((target(...))), take an argument and
+   set the current options from the argument.  If we have a list, recursively
+   go over the list.  */
+
+static bool
+arm_valid_target_attribute_rec (tree args,  struct gcc_options *opts)
+{
+  if (TREE_CODE (args) == TREE_LIST)
+    {
+      bool ret = true;
+      for (; args; args = TREE_CHAIN (args))
+	if (TREE_VALUE (args)
+	    && !arm_valid_target_attribute_rec (TREE_VALUE (args), opts))
+	  ret = false;
+      return ret;
+    }
+
+  else if (TREE_CODE (args) != STRING_CST)
+    {
+      error ("attribute %<target%> argument not a string");
+      return false;
+    }
+
+  char *argstr = ASTRDUP (TREE_STRING_POINTER (args));
+  while (argstr && *argstr != '\0')
+    {
+      while (ISSPACE (*argstr))
+	argstr++;
+
+      if (!strcmp (argstr, "thumb"))
+	{
+	  opts->x_target_flags |= MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      if (!strcmp (argstr, "arm"))
+	{
+	  opts->x_target_flags &= ~MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      warning (0, "attribute(target(\"%s\")) is unknown", argstr);
+      return false;
+    }
+
+  return false;
+}
+
+/* Return a TARGET_OPTION_NODE tree of the target options listed or NULL.  */
+
+tree
+arm_valid_target_attribute_tree (tree args, struct gcc_options *opts,
+				 struct gcc_options *opts_set)
+{
+  if (!arm_valid_target_attribute_rec (args, opts))
+    return NULL_TREE;
+
+  /* Do any overrides, such as global options arch=xxx.  */
+  arm_option_override_internal (opts, opts_set);
+
+  return build_target_option_node (opts);
+}
+
+/* Hook to validate attribute((target("string"))).  */
+
+static bool
+arm_valid_target_attribute_p (tree fndecl, tree ARG_UNUSED (name),
+			      tree args, int ARG_UNUSED (flags))
+{
+  bool ret = true;
+  struct gcc_options func_options;
+  tree cur_tree, new_optimize;
+  gcc_assert ((fndecl != NULL_TREE) && (args != NULL_TREE));
+
+  /* Get the optimization options of the current function.  */
+  tree func_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl);
+
+  /* If the function changed the optimization levels as well as setting target
+     options, start with the optimizations specified.  */
+  if (!func_optimize)
+    func_optimize = optimization_default_node;
+
+  /* Init func_options.  */
+  memset (&func_options, 0, sizeof (func_options));
+  init_options_struct (&func_options, NULL);
+  lang_hooks.init_options_struct (&func_options);
+
+  /* Initialize func_options to the defaults.  */
+  cl_optimization_restore (&func_options,
+			   TREE_OPTIMIZATION (func_optimize));
+
+  cl_target_option_restore (&func_options,
+			    TREE_TARGET_OPTION (target_option_default_node));
+
+  /* Set func_options flags with new target mode.  */
+  cur_tree = arm_valid_target_attribute_tree (args, &func_options,
+					      &global_options_set);
+
+  if (cur_tree == NULL_TREE)
+    ret = false;
+
+  new_optimize = build_optimization_node (&func_options);
+
+  DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = cur_tree;
+
+  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl) = new_optimize;
+
+  return ret;
+}
+
 void
 arm_declare_function_name (FILE *stream, const char *name, tree decl)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (stream, "\t.syntax unified\n");
+  else
+    fprintf (stream, "\t.syntax divided\n");
+
   if (TARGET_THUMB)
     {
       if (is_called_in_ARM_mode (decl)
@@ -29285,6 +29525,8 @@
       else
 	fprintf (stream, "\t.thumb\n\t.thumb_func\n");
     }
+  else
+    fprintf (stream, "\t.arm\n");
 
   if (TARGET_POKE_FUNCTION_NAME)
     arm_poke_function_name (stream, (const char *) name);
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.h gnu_trunk.p4/gcc/gcc/config/arm/arm.h
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.h	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.h	2015-05-06 14:36:32.227213416 +0200
@@ -2332,4 +2332,8 @@
 
 #define DRIVER_SELF_SPECS MCPU_MTUNE_NATIVE_SPECS
 #define TARGET_SUPPORTS_WIDE_INT 1
+
+/* For switching between functions with different target attributes.  */
+#define SWITCHABLE_TARGET 1
+
 #endif /* ! GCC_ARM_H */
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.md gnu_trunk.p4/gcc/gcc/config/arm/arm.md
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.md	2015-05-06 14:31:40.678713158 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.md	2015-05-06 14:36:32.231213422 +0200
@@ -7722,6 +7722,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[0]))"
   "*
   {
+   rtx op = operands[0];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a0(PLT)\" : \"bl%?\\t%a0\";
   }"
   [(set_attr "type" "call")]
@@ -7739,6 +7746,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[1]))"
   "*
   {
+   rtx op = operands[1];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a1(PLT)\" : \"bl%?\\t%a1\";
   }"
   [(set_attr "type" "call")]
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm.opt gnu_trunk.p4/gcc/gcc/config/arm/arm.opt
--- gnu_trunk.p3/gcc/gcc/config/arm/arm.opt	2015-03-30 10:44:52.901327167 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.opt	2015-05-06 14:36:32.231213422 +0200
@@ -182,7 +182,7 @@
 Specify the minimum bit alignment of structures
 
 mthumb
-Target Report RejectNegative Mask(THUMB)
+Target Report RejectNegative Mask(THUMB) Save
 Generate code for Thumb state
 
 mthumb-interwork
@@ -246,7 +246,7 @@
 Only generate absolute relocations on word sized values.
 
 mrestrict-it
-Target Report Var(arm_restrict_it) Init(2)
+Target Report Var(arm_restrict_it) Init(2) Save
 Generate IT blocks appropriate for ARMv8.
 
 mold-rtx-costs
@@ -275,5 +275,5 @@
 Assume loading data from flash is slower than fetching instructions.
 
 masm-syntax-unified
-Target Report Var(inline_asm_unified) Init(0)
+Target Report Var(inline_asm_unified) Init(0) Save
 Assume unified syntax for Thumb inline assembly code.
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/config/arm/arm-protos.h gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h
--- gnu_trunk.p3/gcc/gcc/config/arm/arm-protos.h	2015-05-06 14:31:48.750726995 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h	2015-05-06 14:36:32.231213422 +0200
@@ -210,6 +210,9 @@
 extern int arm_dllimport_p (tree);
 extern void arm_mark_dllexport (tree);
 extern void arm_mark_dllimport (tree);
+extern bool arm_change_mode_p (tree);
+extern tree arm_valid_target_attribute_tree (tree, struct gcc_options *,
+					     struct gcc_options *);
 #endif
 
 extern void arm_pr_long_calls (struct cpp_reader *);
@@ -317,6 +320,8 @@
 
 extern void arm_emit_eabi_attribute (const char *, int, int);
 
+extern void arm_reset_previous_fndecl (void);
+
 /* Defined in gcc/common/config/arm-common.c.  */
 extern const char *arm_rewrite_selected_cpu (const char *name);
 
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/extend.texi gnu_trunk.p4/gcc/gcc/doc/extend.texi
--- gnu_trunk.p3/gcc/gcc/doc/extend.texi	2015-05-06 09:00:31.232943164 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/extend.texi	2015-05-07 09:43:01.087775682 +0200
@@ -3067,8 +3067,9 @@
 or separate the options with a comma (@samp{,}) within a single string.
 
 The options supported are specific to each target; refer to @ref{x86
-Function Attributes}, @ref{PowerPC Function Attributes}, and
-@ref{Nios II Function Attributes}, for details.
+Function Attributes}, @ref{PowerPC Function Attributes},
+@ref{ARM Function Attributes},and @ref{Nios II Function Attributes},
+for details.
 
 @item unused
 @cindex @code{unused} function attribute
@@ -3417,6 +3418,26 @@
 
 Variadic functions always use the @code{"aapcs"} calling convention and
 the compiler rejects attempts to specify an alternative.
+
+@item target (@var{options})
+@cindex @code{target} function attribute
+As discussed in @ref{Common Function Attributes}, this attribute 
+allows specification of target-specific compilation options.
+
+On ARM, the following options are allowed:
+
+@table @samp
+@item thumb
+@cindex @code{target("thumb")} function attribute, ARM
+Force Thumb Thumb-2 code generation, depending on the architecture.
+
+@item arm
+@cindex @code{target("arm")} function attribute, ARM
+Force ARM code generation.
+@end table
+
+Functions from different modes can be inlined in the caller's mode.
+
 @end table
 
 @node AVR Function Attributes
@@ -18436,8 +18457,9 @@
 @xref{Function Attributes}, for more information about the
 @code{target} attribute and the attribute syntax.
 
-The @code{#pragma GCC target} pragma is presently implemented for
-x86, PowerPC, and Nios II targets only.
+The @code{#pragma GCC target} pragma is implemented for
+ARM, x86, PowerPC, and Nios II targets.
+
 @end table
 
 @table @code
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/invoke.texi gnu_trunk.p4/gcc/gcc/doc/invoke.texi
--- gnu_trunk.p3/gcc/gcc/doc/invoke.texi	2015-05-06 09:00:31.232943164 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/invoke.texi	2015-05-07 09:10:04.612347618 +0200
@@ -13434,6 +13434,10 @@
 configuring GCC with the @option{--with-mode=}@var{state}
 configure option.
 
+You can also override the ARM and Thumb mode for each function
+by using the @code{target("thumb")} and @code{target("arm")} function attributes
+(@pxref{ARM Function Attributes}) or pragmas (@pxref{Function Specific Option Pragmas}).
+
 @item -mtpcs-frame
 @opindex mtpcs-frame
 Generate a stack frame that is compliant with the Thumb Procedure Call
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is recogniwed.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".arm" } } */
+/* { dg-final { scan-assembler-not "ite" } } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is rejected for M profile.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv6-m" } } */
+/* { dg-add-options arm_arch_v6m } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{  /* { dg-error "does not support" } */
+  return a ? 1 : 5;
+}
+
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target thumb is recogniwed. */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".thumb" } } */
+/* { dg-final { scan-assembler "ite" } } */
+
+int __attribute__((target("thumb")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c
--- gnu_trunk.p3/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	2015-05-06 14:36:32.335213601 +0200
@@ -0,0 +1,24 @@
+/* Check that a change mode to a static function is correctly handled. */
+/* { dg-do run } */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+static void
+ __attribute__((__noinline__)) 
+foo (void)
+{
+  __asm__ ("");
+}
+
+static void
+__attribute__((__noinline__)) 
+__attribute__((target("thumb")))
+bar (void)
+{
+  __asm__ ("");
+}
+
+int main()
+{
+  foo();
+  bar();
+}

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[Ramana Radhakrishnan]

I'm still playing with the code, so this is a partial review.

We should prevent inlining of ARM state functions into functions we know 
will be T16 if !TARGET_SOFT_FLOAT on the grounds that the architecture 
doesn't have floating point instruction encodings in the T16 ISA 
(Thumb1). We'll just cause internal compiler errors if we allow this.


On 07/05/15 00:03, Sandra Loosemore wrote:
> On 05/06/2015 08:24 AM, Christian Bruel wrote:
>> diff '--exclude=.svn' -ruN gnu_trunk.p3/gcc/gcc/doc/extend.texi gnu_trunk.p4/gcc/gcc/doc/extend.texi
>> --- gnu_trunk.p3/gcc/gcc/doc/extend.texi	2015-05-06 09:00:31.232943164 +0200
>> +++ gnu_trunk.p4/gcc/gcc/doc/extend.texi	2015-05-06 14:50:05.632612233 +0200
>> @@ -3419,6 +3419,25 @@
>>   the compiler rejects attempts to specify an alternative.
>>   @end table
>>
>> +@item target (@var{options})
>> +@cindex @code{target} function attribute
>> +As discussed in @ref{Common Function Attributes}, this attribute
>> +allows specification of target-specific compilation options.
>> +
>> +On ARM, the following options are allowed:
>> +
>> +@table @samp
>> +@item thumb
>> +@cindex @code{target("thumb")} function attribute, ARM
>> +Force Thumb1 Thumb2 code generation depending on the architecture.
>
> "Force Thumb or Thumb-2 code generation, depending on the architecture."

I'd rather it said something like

"Force code generation in the Thumb (T16/ T32) ISA. The exact 
instructions chosen depends on the architecture levels chosen."

>> +
>> +@item arm
>> +@cindex @code{target("arm")} function attribute, ARM
>> +Force ARM code generation.

"Force code generation in the ARM (A32) ISA."

>> +@end table
>> +
>> +Functions from different modes can be inlined using the caller mode.

Rewrite this based on the review comment about inlining in the Thumb16 
state from ARM state.

  	
>
> "...the caller's mode."
>
>> +
>>   @node AVR Function Attributes
>>   @subsection AVR Function Attributes
>>
>> @@ -18436,8 +18455,9 @@
>>   @xref{Function Attributes}, for more information about the
>>   @code{target} attribute and the attribute syntax.
>>
>> -The @code{#pragma GCC target} pragma is presently implemented for
>> -x86, PowerPC, and Nios II targets only.
>> +The @code{#pragma GCC target} pragma is implemented for
>> +ARM, x86, PowerPC, and Nios II targets.
>> +

I'd rather say this once we have proper support with arch, cpu and fpu 
options enabled. Until such a time I think this hunk is a bit premature.


Ramana

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (4th)

[Christian Bruel]

Hi Ramana,

On 05/08/2015 10:31 AM, Ramana Radhakrishnan wrote:
>
> I'm still playing with the code, so this is a partial review.
>
> We should prevent inlining of ARM state functions into functions we know
> will be T16 if !TARGET_SOFT_FLOAT on the grounds that the architecture
> doesn't have floating point instruction encodings in the T16 ISA
> (Thumb1). We'll just cause internal compiler errors if we allow this.
>

I tried to forge a bit with this situation, but I couldn't generate such 
inconsistencies, as the situation is rejected with a :
"sorry, unimplemented: Thumb-1 hard-float VFP ABI"
when using -march=armv6 -mthumb -mhard-float (would that match with T16 
&& !TARGET_SOFT_FLOAT)

Do you have the example producing an ICE ? That would be interesting to 
add it in the testsuite.

by the way, I think the error message should be changed from

"sorry, unimplemented: Thumb-1 hard-float VFP ABI"

to a user error:

"Can't use Thumb-1 hard-float VFP ABI"

Christian

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Christian Bruel]

[-- Attachment #1: Type: text/plain, Size: 497 bytes --]

Hi,

Here is again a new version for patch [4/6]: (Implements and document 
the hooks to support target_attributes.)

  - Rewrote for conflicts introduced by the new macros defined in
    https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01198.html

  - Take your comments and Sandra's for documentation

  - I'd like to leave the inlining question apart with its own patch 
until we settle it. Is it OK with you ?
    https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01527.html

many thanks,

Christian

[-- Attachment #2: p4.patch --]
[-- Type: text/x-patch, Size: 21763 bytes --]

2014-09-23  Christian Bruel  <christian.bruel@st.com>

	* config/arm/arm.opt (THUMB, arm_restrict_it, inline_asm_unified): Save.
	* config/arm/arm.h (arm_valid_target_attribute_tree): Declare.
	(arm_reset_previous_fndecl, arm_change_mode_p): Likewise.
	(SWITCHABLE_TARGET): Define.
	* config/arm/arm.c (arm_reset_previous_fndecl): New functions.
	(arm_valid_target_attribute_tree, arm_change_mode_p): Likewise.
	(arm_valid_target_attribute_p): Likewise.
	(arm_set_current_function, arm_can_inline_p): Likewise.
	(arm_valid_target_attribute_rec): Likewise.
	(arm_previous_fndecl): New variable.
	(TARGET_SET_CURRENT_FUNCTION, TARGET_OPTION_VALID_ATTRIBUTE_P): Define.
	(TARGET_CAN_INLINE_P): Define.
	(arm_asm_trampoline_template): Emit mode.
	(arm_file_start): Don't set unified syntax.
	(arm_declare_function_name): Set unified syntax and mode.
	(arm_option_override): Init target_option_default_node.
	and target_option_current_node.
	* config/arm/arm.md (*call_value_symbol): Set mode when possible.
	(*call_symbol): Likewise.
	* doc/extend.texi: Document ARM/Thumb target attribute.
	* doc/invoke.texi: Likewise.

2014-09-23  Christian Bruel  <christian.bruel@st.com>

	* gcc.target/arm/attr_arm.c: New test
	* gcc.target/arm/attr_arm-err.c: New test
	* gcc.target/arm/attr_thumb.c: New test
	* gcc.target/arm/attr_thumb-static.c: New test

diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/config/arm/arm.c gnu_trunk.p4/gcc/gcc/config/arm/arm.c
--- gnu_trunk.p2/gcc/gcc/config/arm/arm.c	2015-05-18 09:59:22.711435629 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.c	2015-05-13 13:51:47.427088369 +0200
@@ -94,6 +94,7 @@
 #include "opts.h"
 #include "dumpfile.h"
 #include "gimple-expr.h"
+#include "target-globals.h"
 #include "builtins.h"
 #include "tm-constrs.h"
 #include "rtl-iter.h"
@@ -265,6 +266,9 @@
 static void arm_expand_builtin_va_start (tree, rtx);
 static tree arm_gimplify_va_arg_expr (tree, tree, gimple_seq *, gimple_seq *);
 static void arm_option_override (void);
+static void arm_set_current_function (tree);
+static bool arm_can_inline_p (tree, tree);
+static bool arm_valid_target_attribute_p (tree, tree, tree, int);
 static unsigned HOST_WIDE_INT arm_shift_truncation_mask (machine_mode);
 static bool arm_macro_fusion_p (void);
 static bool arm_cannot_copy_insn_p (rtx_insn *);
@@ -413,6 +417,9 @@
 #undef  TARGET_ASM_FUNCTION_EPILOGUE
 #define TARGET_ASM_FUNCTION_EPILOGUE arm_output_function_epilogue
 
+#undef TARGET_CAN_INLINE_P
+#define TARGET_CAN_INLINE_P arm_can_inline_p
+
 #undef  TARGET_OPTION_OVERRIDE
 #define TARGET_OPTION_OVERRIDE arm_option_override
 
@@ -431,6 +438,12 @@
 #undef  TARGET_SCHED_ADJUST_COST
 #define TARGET_SCHED_ADJUST_COST arm_adjust_cost
 
+#undef TARGET_SET_CURRENT_FUNCTION
+#define TARGET_SET_CURRENT_FUNCTION arm_set_current_function
+
+#undef TARGET_OPTION_VALID_ATTRIBUTE_P
+#define TARGET_OPTION_VALID_ATTRIBUTE_P arm_valid_target_attribute_p
+
 #undef TARGET_SCHED_REORDER
 #define TARGET_SCHED_REORDER arm_sched_reorder
 
@@ -2777,6 +2790,9 @@
     max_insns_skipped = current_tune->max_insns_skipped;
 }
 
+/* Options after initial target override.  */
+static GTY(()) tree init_optimize;
+
 /* Reset options between modes that the user has specified.  */
 static void
 arm_option_override_internal (struct gcc_options *opts,
@@ -2799,23 +2815,29 @@
   if (TARGET_THUMB_P (opts->x_target_flags) && TARGET_CALLEE_INTERWORKING)
     opts->x_target_flags |= MASK_INTERWORK;
 
+  /* need to remember initial values so combinaisons of options like
+     -mflip-thumb -mthumb -fno-schedule-insns work for any attribute.  */
+  cl_optimization *to = TREE_OPTIMIZATION (init_optimize);
+
   if (! opts_set->x_arm_restrict_it)
     opts->x_arm_restrict_it = arm_arch8;
 
   if (!TARGET_THUMB2_P (opts->x_target_flags))
     opts->x_arm_restrict_it = 0;
 
+  /* Don't warn since it's on by default in -O2.  */
   if (TARGET_THUMB1_P (opts->x_target_flags))
-    {
-      /* Don't warn since it's on by default in -O2.  */
-      opts->x_flag_schedule_insns = 0;
-    }
+    opts->x_flag_schedule_insns = 0;
+  else
+    opts->x_flag_schedule_insns = to->x_flag_schedule_insns;
 
   /* Disable shrink-wrap when optimizing function for size, since it tends to
      generate additional returns.  */
   if (optimize_function_for_size_p (cfun)
       && TARGET_THUMB2_P (opts->x_target_flags))
     opts->x_flag_shrink_wrap = false;
+  else
+    opts->x_flag_shrink_wrap = to->x_flag_shrink_wrap;
 
   /* In Thumb1 mode, we emit the epilogue in RTL, but the last insn
      - epilogue_insns - does not accurately model the corresponding insns
@@ -2827,6 +2849,8 @@
      fipa-ra.  */
   if (TARGET_THUMB1_P (opts->x_target_flags))
     opts->x_flag_ipa_ra = 0;
+  else
+    opts->x_flag_ipa_ra = to->x_flag_ipa_ra;
 
   /* Thumb2 inline assembly code should always use unified syntax.
      This will apply to ARM and Thumb1 eventually.  */
@@ -3329,12 +3353,20 @@
       && (!arm_arch7 || !current_tune->prefer_ldrd_strd))
     flag_schedule_fusion = 0;
 
+  /* Need to remember initial options before they are overriden.  */
+  init_optimize = build_optimization_node (&global_options);
+
   arm_option_override_internal (&global_options, &global_options_set);
   arm_option_check_internal (&global_options);
   arm_option_params_internal (&global_options);
 
   /* Register global variables with the garbage collector.  */
   arm_add_gc_roots ();
+
+  /* Save the initial options in case the user does function specific
+     options.  */
+  target_option_default_node = target_option_current_node
+    = build_target_option_node (&global_options);
 }
 
 static void
@@ -3488,13 +3520,20 @@
 static void
 arm_asm_trampoline_template (FILE *f)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (f, "\t.syntax unified\n");
+  else
+    fprintf (f, "\t.syntax divided\n");
+
   if (TARGET_ARM)
     {
+      fprintf (f, "\t.arm\n");
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", STATIC_CHAIN_REGNUM, PC_REGNUM);
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", PC_REGNUM, PC_REGNUM);
     }
   else if (TARGET_THUMB2)
     {
+      fprintf (f, "\t.thumb\n");
       /* The Thumb-2 trampoline is similar to the arm implementation.
 	 Unlike 16-bit Thumb, we enter the stub in thumb mode.  */
       asm_fprintf (f, "\tldr.w\t%r, [%r, #4]\n",
@@ -24190,6 +24229,24 @@
     mark_reg_pointer (arg_pointer_rtx, PARM_BOUNDARY);
 }
 
+/* Check that FUNC is called with a different mode.  */
+
+bool
+arm_change_mode_p (tree func)
+{
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    return false;
+
+  tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (func);
+
+  if (!callee_tree)
+    callee_tree = target_option_default_node;
+
+  struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
+  int flags = callee_opts ->x_target_flags;
+
+  return (TARGET_THUMB_P (flags) != TARGET_THUMB);
+}
 
 /* Like arm_compute_initial_elimination offset.  Simpler because there
    isn't an ABI specified frame pointer for Thumb.  Instead, we set it
@@ -25517,9 +25574,6 @@
 {
   int val;
 
-  if (TARGET_UNIFIED_ASM)
-    asm_fprintf (asm_out_file, "\t.syntax unified\n");
-
   if (TARGET_BPABI)
     {
       const char *fpu_name;
@@ -29266,9 +29320,196 @@
 	  && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)));
 }
 
+/* Remember the last target of arm_set_current_function.  */
+static GTY(()) tree arm_previous_fndecl;
+
+/* Invalidate arm_previous_fndecl.  */
+void
+arm_reset_previous_fndecl (void)
+{
+  arm_previous_fndecl = NULL_TREE;
+}
+
+/* Establish appropriate back-end context for processing the function
+   FNDECL.  The argument might be NULL to indicate processing at top
+   level, outside of any function scope.  */
+static void
+arm_set_current_function (tree fndecl)
+{
+  if (!fndecl || fndecl == arm_previous_fndecl)
+    return;
+
+  tree old_tree = (arm_previous_fndecl
+		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
+		   : NULL_TREE);
+
+  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
+
+  arm_previous_fndecl = fndecl;
+  if (old_tree == new_tree)
+    ;
+
+  else if (new_tree)
+    {
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  else if (old_tree)
+    {
+      new_tree = target_option_current_node;
+
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else if (new_tree == target_option_default_node)
+	restore_target_globals (&default_target_globals);
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  arm_option_params_internal (&global_options);
+}
+
+/* Hook to determine if one function can safely inline another.  */
+
+static bool
+arm_can_inline_p (tree caller ATTRIBUTE_UNUSED, tree callee ATTRIBUTE_UNUSED)
+{
+  /* Overidde default hook: Always OK to inline between different modes. 
+     Function with mode specific instructions, e.g using asm, must be explicitely 
+     protected with noinline.  */
+  return true;
+}
+
+/* Inner function to process the attribute((target(...))), take an argument and
+   set the current options from the argument.  If we have a list, recursively
+   go over the list.  */
+
+static bool
+arm_valid_target_attribute_rec (tree args,  struct gcc_options *opts)
+{
+  if (TREE_CODE (args) == TREE_LIST)
+    {
+      bool ret = true;
+      for (; args; args = TREE_CHAIN (args))
+	if (TREE_VALUE (args)
+	    && !arm_valid_target_attribute_rec (TREE_VALUE (args), opts))
+	  ret = false;
+      return ret;
+    }
+
+  else if (TREE_CODE (args) != STRING_CST)
+    {
+      error ("attribute %<target%> argument not a string");
+      return false;
+    }
+
+  char *argstr = ASTRDUP (TREE_STRING_POINTER (args));
+  while (argstr && *argstr != '\0')
+    {
+      while (ISSPACE (*argstr))
+	argstr++;
+
+      if (!strcmp (argstr, "thumb"))
+	{
+	  opts->x_target_flags |= MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      if (!strcmp (argstr, "arm"))
+	{
+	  opts->x_target_flags &= ~MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      warning (0, "attribute(target(\"%s\")) is unknown", argstr);
+      return false;
+    }
+
+  return false;
+}
+
+/* Return a TARGET_OPTION_NODE tree of the target options listed or NULL.  */
+
+tree
+arm_valid_target_attribute_tree (tree args, struct gcc_options *opts,
+				 struct gcc_options *opts_set)
+{
+  if (!arm_valid_target_attribute_rec (args, opts))
+    return NULL_TREE;
+
+  /* Do any overrides, such as global options arch=xxx.  */
+  arm_option_override_internal (opts, opts_set);
+
+  return build_target_option_node (opts);
+}
+
+/* Hook to validate attribute((target("string"))).  */
+
+static bool
+arm_valid_target_attribute_p (tree fndecl, tree ARG_UNUSED (name),
+			      tree args, int ARG_UNUSED (flags))
+{
+  bool ret = true;
+  struct gcc_options func_options;
+  tree cur_tree, new_optimize;
+  gcc_assert ((fndecl != NULL_TREE) && (args != NULL_TREE));
+
+  /* Get the optimization options of the current function.  */
+  tree func_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl);
+
+  /* If the function changed the optimization levels as well as setting target
+     options, start with the optimizations specified.  */
+  if (!func_optimize)
+    func_optimize = optimization_default_node;
+
+  /* Init func_options.  */
+  memset (&func_options, 0, sizeof (func_options));
+  init_options_struct (&func_options, NULL);
+  lang_hooks.init_options_struct (&func_options);
+
+  /* Initialize func_options to the defaults.  */
+  cl_optimization_restore (&func_options,
+			   TREE_OPTIMIZATION (func_optimize));
+
+  cl_target_option_restore (&func_options,
+			    TREE_TARGET_OPTION (target_option_default_node));
+
+  /* Set func_options flags with new target mode.  */
+  cur_tree = arm_valid_target_attribute_tree (args, &func_options,
+					      &global_options_set);
+
+  if (cur_tree == NULL_TREE)
+    ret = false;
+
+  new_optimize = build_optimization_node (&func_options);
+
+  DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = cur_tree;
+
+  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl) = new_optimize;
+
+  return ret;
+}
+
 void
 arm_declare_function_name (FILE *stream, const char *name, tree decl)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (stream, "\t.syntax unified\n");
+  else
+    fprintf (stream, "\t.syntax divided\n");
+
   if (TARGET_THUMB)
     {
       if (is_called_in_ARM_mode (decl)
@@ -29280,6 +29521,8 @@
       else
 	fprintf (stream, "\t.thumb\n\t.thumb_func\n");
     }
+  else
+    fprintf (stream, "\t.arm\n");
 
   if (TARGET_POKE_FUNCTION_NAME)
     arm_poke_function_name (stream, (const char *) name);
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/config/arm/arm.h gnu_trunk.p4/gcc/gcc/config/arm/arm.h
--- gnu_trunk.p2/gcc/gcc/config/arm/arm.h	2015-05-18 09:59:22.715435636 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.h	2015-05-18 09:10:32.898017110 +0200
@@ -2258,4 +2258,8 @@
 
 #define DRIVER_SELF_SPECS MCPU_MTUNE_NATIVE_SPECS
 #define TARGET_SUPPORTS_WIDE_INT 1
+
+/* For switching between functions with different target attributes.  */
+#define SWITCHABLE_TARGET 1
+
 #endif /* ! GCC_ARM_H */
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/config/arm/arm.md gnu_trunk.p4/gcc/gcc/config/arm/arm.md
--- gnu_trunk.p2/gcc/gcc/config/arm/arm.md	2015-05-18 09:36:56.844875186 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.md	2015-05-18 09:10:32.898017110 +0200
@@ -7738,6 +7738,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[0]))"
   "*
   {
+   rtx op = operands[0];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a0(PLT)\" : \"bl%?\\t%a0\";
   }"
   [(set_attr "type" "call")]
@@ -7755,6 +7762,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[1]))"
   "*
   {
+   rtx op = operands[1];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a1(PLT)\" : \"bl%?\\t%a1\";
   }"
   [(set_attr "type" "call")]
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/config/arm/arm.opt gnu_trunk.p4/gcc/gcc/config/arm/arm.opt
--- gnu_trunk.p2/gcc/gcc/config/arm/arm.opt	2015-03-30 10:44:52.901327167 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm.opt	2015-05-13 12:59:54.625164421 +0200
@@ -182,7 +182,7 @@
 Specify the minimum bit alignment of structures
 
 mthumb
-Target Report RejectNegative Mask(THUMB)
+Target Report RejectNegative Mask(THUMB) Save
 Generate code for Thumb state
 
 mthumb-interwork
@@ -246,7 +246,7 @@
 Only generate absolute relocations on word sized values.
 
 mrestrict-it
-Target Report Var(arm_restrict_it) Init(2)
+Target Report Var(arm_restrict_it) Init(2) Save
 Generate IT blocks appropriate for ARMv8.
 
 mold-rtx-costs
@@ -275,5 +275,5 @@
 Assume loading data from flash is slower than fetching instructions.
 
 masm-syntax-unified
-Target Report Var(inline_asm_unified) Init(0)
+Target Report Var(inline_asm_unified) Init(0) Save
 Assume unified syntax for Thumb inline assembly code.
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/config/arm/arm-protos.h gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h
--- gnu_trunk.p2/gcc/gcc/config/arm/arm-protos.h	2015-05-18 09:59:19.267429002 +0200
+++ gnu_trunk.p4/gcc/gcc/config/arm/arm-protos.h	2015-05-13 12:59:54.653164472 +0200
@@ -210,6 +210,9 @@
 extern int arm_dllimport_p (tree);
 extern void arm_mark_dllexport (tree);
 extern void arm_mark_dllimport (tree);
+extern bool arm_change_mode_p (tree);
+extern tree arm_valid_target_attribute_tree (tree, struct gcc_options *,
+					     struct gcc_options *);
 #endif
 
 extern void arm_pr_long_calls (struct cpp_reader *);
@@ -326,6 +329,8 @@
 
 extern void arm_emit_eabi_attribute (const char *, int, int);
 
+extern void arm_reset_previous_fndecl (void);
+
 /* Defined in gcc/common/config/arm-common.c.  */
 extern const char *arm_rewrite_selected_cpu (const char *name);
 
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/doc/extend.texi gnu_trunk.p4/gcc/gcc/doc/extend.texi
--- gnu_trunk.p2/gcc/gcc/doc/extend.texi	2015-05-13 09:07:31.339106236 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/extend.texi	2015-05-18 09:08:54.221837117 +0200
@@ -3067,8 +3067,9 @@
 or separate the options with a comma (@samp{,}) within a single string.
 
 The options supported are specific to each target; refer to @ref{x86
-Function Attributes}, @ref{PowerPC Function Attributes}, and
-@ref{Nios II Function Attributes}, for details.
+Function Attributes}, @ref{PowerPC Function Attributes},
+@ref{ARM Function Attributes},and @ref{Nios II Function Attributes},
+for details.
 
 @item unused
 @cindex @code{unused} function attribute
@@ -3417,6 +3418,27 @@
 
 Variadic functions always use the @code{"aapcs"} calling convention and
 the compiler rejects attempts to specify an alternative.
+
+@item target (@var{options})
+@cindex @code{target} function attribute
+As discussed in @ref{Common Function Attributes}, this attribute 
+allows specification of target-specific compilation options.
+
+On ARM, the following options are allowed:
+
+@table @samp
+@item thumb
+@cindex @code{target("thumb")} function attribute, ARM
+Force code generation in the Thumb (T16/T32) ISA, depending on the
+architecture level.
+
+@item arm
+@cindex @code{target("arm")} function attribute, ARM
+Force code generation in the ARM (A32) ISA.
+@end table
+
+Functions from different modes can be inlined in the caller's mode.
+
 @end table
 
 @node AVR Function Attributes
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/doc/invoke.texi gnu_trunk.p4/gcc/gcc/doc/invoke.texi
--- gnu_trunk.p2/gcc/gcc/doc/invoke.texi	2015-05-18 09:36:52.304866524 +0200
+++ gnu_trunk.p4/gcc/gcc/doc/invoke.texi	2015-05-18 09:10:29.078010152 +0200
@@ -13508,6 +13508,10 @@
 configuring GCC with the @option{--with-mode=}@var{state}
 configure option.
 
+You can also override the ARM and Thumb mode for each function
+by using the @code{target("thumb")} and @code{target("arm")} function attributes
+(@pxref{ARM Function Attributes}) or pragmas (@pxref{Function Specific Option Pragmas}).
+
 @item -mtpcs-frame
 @opindex mtpcs-frame
 Generate a stack frame that is compliant with the Thumb Procedure Call
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c
--- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	2015-05-07 18:15:34.177443930 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is recogniwed.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".arm" } } */
+/* { dg-final { scan-assembler-not "ite" } } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c
--- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	2015-05-07 18:15:34.177443930 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is rejected for M profile.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv6-m" } } */
+/* { dg-add-options arm_arch_v6m } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{  /* { dg-error "does not support" } */
+  return a ? 1 : 5;
+}
+
+
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c
--- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	2015-05-07 18:15:34.177443930 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target thumb is recogniwed. */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".thumb" } } */
+/* { dg-final { scan-assembler "ite" } } */
+
+int __attribute__((target("thumb")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c
--- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb-static.c	2015-05-07 18:15:34.177443930 +0200
@@ -0,0 +1,24 @@
+/* Check that a change mode to a static function is correctly handled. */
+/* { dg-do run } */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+static void
+ __attribute__((__noinline__)) 
+foo (void)
+{
+  __asm__ ("");
+}
+
+static void
+__attribute__((__noinline__)) 
+__attribute__((target("thumb")))
+bar (void)
+{
+  __asm__ ("");
+}
+
+int main()
+{
+  foo();
+  bar();
+}

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Kyrill Tkachov]

On 18/05/15 09:14, Christian Bruel wrote:
> Hi,

Hi Christian,
A couple comments inline.
Overall, the approach looks ok to me, though I think we'll have to
generalise arm_valid_target_attribute_rec in the future if we want
to allow other target attributes.

Thanks,
Kyrill

>
> Here is again a new version for patch [4/6]: (Implements and document
> the hooks to support target_attributes.)
>
>    - Rewrote for conflicts introduced by the new macros defined in
>      https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01198.html
>
>    - Take your comments and Sandra's for documentation
>
>    - I'd like to leave the inlining question apart with its own patch
> until we settle it. Is it OK with you ?
>      https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01527.html
>
> many thanks,
>
> Christian
>
> p4.patch
>
>
> 2014-09-23  Christian Bruel<christian.bruel@st.com>
>
> 	* config/arm/arm.opt (THUMB, arm_restrict_it, inline_asm_unified): Save.
> 	* config/arm/arm.h (arm_valid_target_attribute_tree): Declare.
> 	(arm_reset_previous_fndecl, arm_change_mode_p): Likewise.
> 	(SWITCHABLE_TARGET): Define.
> 	* config/arm/arm.c (arm_reset_previous_fndecl): New functions.
> 	(arm_valid_target_attribute_tree, arm_change_mode_p): Likewise.
> 	(arm_valid_target_attribute_p): Likewise.
> 	(arm_set_current_function, arm_can_inline_p): Likewise.
> 	(arm_valid_target_attribute_rec): Likewise.
> 	(arm_previous_fndecl): New variable.
> 	(TARGET_SET_CURRENT_FUNCTION, TARGET_OPTION_VALID_ATTRIBUTE_P): Define.
> 	(TARGET_CAN_INLINE_P): Define.
> 	(arm_asm_trampoline_template): Emit mode.
> 	(arm_file_start): Don't set unified syntax.
> 	(arm_declare_function_name): Set unified syntax and mode.
> 	(arm_option_override): Init target_option_default_node.
> 	and target_option_current_node.
> 	* config/arm/arm.md (*call_value_symbol): Set mode when possible.
> 	(*call_symbol): Likewise.
> 	* doc/extend.texi: Document ARM/Thumb target attribute.
> 	* doc/invoke.texi: Likewise.
>
> 2014-09-23  Christian Bruel<christian.bruel@st.com>
>
> 	* gcc.target/arm/attr_arm.c: New test
> 	* gcc.target/arm/attr_arm-err.c: New test
> 	* gcc.target/arm/attr_thumb.c: New test
> 	* gcc.target/arm/attr_thumb-static.c: New test

Full stops at end of "New test"

<snip>

  
+/* Check that FUNC is called with a different mode.  */
+
+bool
+arm_change_mode_p (tree func)
+{
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    return false;
+
+  tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (func);
+
+  if (!callee_tree)
+    callee_tree = target_option_default_node;
+
+  struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
+  int flags = callee_opts ->x_target_flags;


No space after callee_opts.

<snip>
  
+/* Remember the last target of arm_set_current_function.  */
+static GTY(()) tree arm_previous_fndecl;
+
+/* Invalidate arm_previous_fndecl.  */
+void
+arm_reset_previous_fndecl (void)
+{
+  arm_previous_fndecl = NULL_TREE;
+}
+
+/* Establish appropriate back-end context for processing the function
+   FNDECL.  The argument might be NULL to indicate processing at top
+   level, outside of any function scope.  */
+static void
+arm_set_current_function (tree fndecl)
+{
+  if (!fndecl || fndecl == arm_previous_fndecl)
+    return;
+
+  tree old_tree = (arm_previous_fndecl
+		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
+		   : NULL_TREE);
+
+  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
+
+  arm_previous_fndecl = fndecl;
+  if (old_tree == new_tree)
+    ;
+
+  else if (new_tree)
+    {
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  else if (old_tree)
+    {
+      new_tree = target_option_current_node;
+
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else if (new_tree == target_option_default_node)
+	restore_target_globals (&default_target_globals);
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  arm_option_params_internal (&global_options);


I thought the more common approach was to define TARGET_OPTION_RESTORE
that was supposed to restore the backend state, including calling arm_option_params_internal?
That way, cl_target_option_restore would do all that needs to be done to restore the backend.

<snip>

diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c
--- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	1970-01-01 01:00:00.000000000 +0100
+++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm.c	2015-05-07 18:15:34.177443930 +0200
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is recogniwed.  */


s/recogniwed/recognized/

> +/* { dg-do compile } */
> +/* { dg-require-effective-target arm_arm_ok } */
> +/* { dg-options "-O2" } */
> +/* { dg-final { scan-assembler ".arm" } } */
> +/* { dg-final { scan-assembler-not "ite" } } */
> +
> +int __attribute__((target("arm")))
> +foo(int a)
> +{
> +  return a ? 1 : 5;
> +}
> +
> diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c
> --- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	1970-01-01 01:00:00.000000000 +0100
> +++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_arm-err.c	2015-05-07 18:15:34.177443930 +0200
> @@ -0,0 +1,13 @@
> +/* Check that attribute target arm is rejected for M profile.  */
> +/* { dg-do compile } */
> +/* { dg-require-effective-target arm_arm_ok } */
> +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv6-m" } } */
> +/* { dg-add-options arm_arch_v6m } */
> +
> +int __attribute__((target("arm")))
> +foo(int a)
> +{  /* { dg-error "does not support" } */
> +  return a ? 1 : 5;
> +}
> +
> +
> diff '--exclude=.svn' -ruN gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c
> --- gnu_trunk.p2/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	1970-01-01 01:00:00.000000000 +0100
> +++ gnu_trunk.p4/gcc/gcc/testsuite/gcc.target/arm/attr_thumb.c	2015-05-07 18:15:34.177443930 +0200
> @@ -0,0 +1,13 @@
> +/* Check that attribute target thumb is recogniwed. */
s/recogniwed/recognized/

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Christian Bruel]

hi Kyrill


On 06/01/2015 12:39 PM, Kyrill Tkachov wrote:
>
> On 18/05/15 09:14, Christian Bruel wrote:
>> Hi,
>
> Hi Christian,
> A couple comments inline.
> Overall, the approach looks ok to me, though I think we'll have to
> generalise arm_valid_target_attribute_rec in the future if we want
> to allow other target attributes.
>

the other fpu target attributes will be part of another set of 
developments, specific parsing strings will be added as they are 
implemented.

> +
> +/* Establish appropriate back-end context for processing the function
> +   FNDECL.  The argument might be NULL to indicate processing at top
> +   level, outside of any function scope.  */
> +static void
> +arm_set_current_function (tree fndecl)
> +{
> +  if (!fndecl || fndecl == arm_previous_fndecl)
> +    return;
> +
> +  tree old_tree = (arm_previous_fndecl
> +		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
> +		   : NULL_TREE);
> +
> +  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
> +
> +  arm_previous_fndecl = fndecl;
> +  if (old_tree == new_tree)
> +    ;
> +
> +  else if (new_tree)
> +    {
> +      cl_target_option_restore (&global_options,
> +				TREE_TARGET_OPTION (new_tree));
> +
> +      if (TREE_TARGET_GLOBALS (new_tree))
> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
> +      else
> +	TREE_TARGET_GLOBALS (new_tree)
> +	  = save_target_globals_default_opts ();
> +    }
> +
> +  else if (old_tree)
> +    {
> +      new_tree = target_option_current_node;
> +
> +      cl_target_option_restore (&global_options,
> +				TREE_TARGET_OPTION (new_tree));
> +      if (TREE_TARGET_GLOBALS (new_tree))
> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
> +      else if (new_tree == target_option_default_node)
> +	restore_target_globals (&default_target_globals);
> +      else
> +	TREE_TARGET_GLOBALS (new_tree)
> +	  = save_target_globals_default_opts ();
> +    }
> +
> +  arm_option_params_internal (&global_options);
>
>
> I thought the more common approach was to define TARGET_OPTION_RESTORE
> that was supposed to restore the backend state, including calling arm_option_params_internal?
> That way, cl_target_option_restore would do all that needs to be done to restore the backend.
>

TARGET_OPTION_RESTORE is fine to restore target-specific
information from struct cl_target_option. Other global states might as 
well be expressed within set_current_function (e.g indeed I might use 
TARGET_OPTION_RESTORE to switch arm_fpu_attr in the fpu neon attribute). 
But IMHO arm_option_params_internal are fine to be called there since 
the 2 params only depend from x_target_flags without the need of a new 
macro.

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Kyrill Tkachov]

On 01/06/15 12:29, Christian Bruel wrote:
> hi Kyrill
>
>
> On 06/01/2015 12:39 PM, Kyrill Tkachov wrote:
>> On 18/05/15 09:14, Christian Bruel wrote:
>>> Hi,
>> Hi Christian,
>> A couple comments inline.
>> Overall, the approach looks ok to me, though I think we'll have to
>> generalise arm_valid_target_attribute_rec in the future if we want
>> to allow other target attributes.
>>
> the other fpu target attributes will be part of another set of
> developments, specific parsing strings will be added as they are
> implemented.

Ok, so you plan on working on fpu attributes as well?

>
>> +
>> +/* Establish appropriate back-end context for processing the function
>> +   FNDECL.  The argument might be NULL to indicate processing at top
>> +   level, outside of any function scope.  */
>> +static void
>> +arm_set_current_function (tree fndecl)
>> +{
>> +  if (!fndecl || fndecl == arm_previous_fndecl)
>> +    return;
>> +
>> +  tree old_tree = (arm_previous_fndecl
>> +		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
>> +		   : NULL_TREE);
>> +
>> +  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
>> +
>> +  arm_previous_fndecl = fndecl;
>> +  if (old_tree == new_tree)
>> +    ;
>> +
>> +  else if (new_tree)
>> +    {
>> +      cl_target_option_restore (&global_options,
>> +				TREE_TARGET_OPTION (new_tree));
>> +
>> +      if (TREE_TARGET_GLOBALS (new_tree))
>> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
>> +      else
>> +	TREE_TARGET_GLOBALS (new_tree)
>> +	  = save_target_globals_default_opts ();
>> +    }
>> +
>> +  else if (old_tree)
>> +    {
>> +      new_tree = target_option_current_node;
>> +
>> +      cl_target_option_restore (&global_options,
>> +				TREE_TARGET_OPTION (new_tree));
>> +      if (TREE_TARGET_GLOBALS (new_tree))
>> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
>> +      else if (new_tree == target_option_default_node)
>> +	restore_target_globals (&default_target_globals);
>> +      else
>> +	TREE_TARGET_GLOBALS (new_tree)
>> +	  = save_target_globals_default_opts ();
>> +    }
>> +
>> +  arm_option_params_internal (&global_options);
>>
>>
>> I thought the more common approach was to define TARGET_OPTION_RESTORE
>> that was supposed to restore the backend state, including calling arm_option_params_internal?
>> That way, cl_target_option_restore would do all that needs to be done to restore the backend.
>>
> TARGET_OPTION_RESTORE is fine to restore target-specific
> information from struct cl_target_option. Other global states might as
> well be expressed within set_current_function (e.g indeed I might use
> TARGET_OPTION_RESTORE to switch arm_fpu_attr in the fpu neon attribute).
> But IMHO arm_option_params_internal are fine to be called there since
> the 2 params only depend from x_target_flags without the need of a new
> macro.

Ok, I see.
The patch looks ok to me modulo the typo nits I pointed out, but I think Ramana
should have the final say here as he's already started reviewing it and it adds quite
a lot of functionality.

Thanks,
Kyrill

>
>

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Christian Bruel]

On 06/01/2015 02:41 PM, Kyrill Tkachov wrote:
>
> On 01/06/15 12:29, Christian Bruel wrote:
>> hi Kyrill
>>
>>
>> On 06/01/2015 12:39 PM, Kyrill Tkachov wrote:
>>> On 18/05/15 09:14, Christian Bruel wrote:
>>>> Hi,
>>> Hi Christian,
>>> A couple comments inline.
>>> Overall, the approach looks ok to me, though I think we'll have to
>>> generalise arm_valid_target_attribute_rec in the future if we want
>>> to allow other target attributes.
>>>
>> the other fpu target attributes will be part of another set of
>> developments, specific parsing strings will be added as they are
>> implemented.
>
> Ok, so you plan on working on fpu attributes as well?

I have a prototype for fpu=neon, it works locally but there are still a 
few corner cases and testing to sort out before sending a draft.

There are so many architectural variants to check that I might ask for 
help once it is a little bit more robust, and some might be similar with 
aarch64's simd.

>
>>
>>> +
>>> +/* Establish appropriate back-end context for processing the function
>>> +   FNDECL.  The argument might be NULL to indicate processing at top
>>> +   level, outside of any function scope.  */
>>> +static void
>>> +arm_set_current_function (tree fndecl)
>>> +{
>>> +  if (!fndecl || fndecl == arm_previous_fndecl)
>>> +    return;
>>> +
>>> +  tree old_tree = (arm_previous_fndecl
>>> +		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
>>> +		   : NULL_TREE);
>>> +
>>> +  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
>>> +
>>> +  arm_previous_fndecl = fndecl;
>>> +  if (old_tree == new_tree)
>>> +    ;
>>> +
>>> +  else if (new_tree)
>>> +    {
>>> +      cl_target_option_restore (&global_options,
>>> +				TREE_TARGET_OPTION (new_tree));
>>> +
>>> +      if (TREE_TARGET_GLOBALS (new_tree))
>>> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
>>> +      else
>>> +	TREE_TARGET_GLOBALS (new_tree)
>>> +	  = save_target_globals_default_opts ();
>>> +    }
>>> +
>>> +  else if (old_tree)
>>> +    {
>>> +      new_tree = target_option_current_node;
>>> +
>>> +      cl_target_option_restore (&global_options,
>>> +				TREE_TARGET_OPTION (new_tree));
>>> +      if (TREE_TARGET_GLOBALS (new_tree))
>>> +	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
>>> +      else if (new_tree == target_option_default_node)
>>> +	restore_target_globals (&default_target_globals);
>>> +      else
>>> +	TREE_TARGET_GLOBALS (new_tree)
>>> +	  = save_target_globals_default_opts ();
>>> +    }
>>> +
>>> +  arm_option_params_internal (&global_options);
>>>
>>>
>>> I thought the more common approach was to define TARGET_OPTION_RESTORE
>>> that was supposed to restore the backend state, including calling arm_option_params_internal?
>>> That way, cl_target_option_restore would do all that needs to be done to restore the backend.
>>>
>> TARGET_OPTION_RESTORE is fine to restore target-specific
>> information from struct cl_target_option. Other global states might as
>> well be expressed within set_current_function (e.g indeed I might use
>> TARGET_OPTION_RESTORE to switch arm_fpu_attr in the fpu neon attribute).
>> But IMHO arm_option_params_internal are fine to be called there since
>> the 2 params only depend from x_target_flags without the need of a new
>> macro.
>
> Ok, I see.
> The patch looks ok to me modulo the typo nits I pointed out, but I think Ramana
> should have the final say here as he's already started reviewing it and it adds quite
> a lot of functionality.

OK thanks, I'll wait for Ramana's final words.

Cheers

Christian

>
> Thanks,
> Kyrill
>
>>
>>
>

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Christian Bruel]

Hi Ramana,

>
> Ok, I see.
> The patch looks ok to me modulo the typo nits I pointed out, but I think Ramana
> should have the final say here as he's already started reviewing it and it adds quite
> a lot of functionality.
>
> Thanks,
> Kyrill
>

do you have other feedbacks for the remaining parts ?

many thanks

Christian

Re: [PATCH, ARM] attribute target (thumb,arm) [4/6] respin (5th)

[Ramana Radhakrishnan]

On 08/06/15 09:45, Christian Bruel wrote:
> Hi Ramana,
>
>>
>> Ok, I see.
>> The patch looks ok to me modulo the typo nits I pointed out, but I
>> think Ramana
>> should have the final say here as he's already started reviewing it
>> and it adds quite
>> a lot of functionality.
>>
>> Thanks,
>> Kyrill
>>
>
> do you have other feedbacks for the remaining parts ?
>
> many thanks
>
> Christian


This is OK, thanks.

Ramana

Re: [PATCH, ARM] (commited) attribute target (thumb,arm) [4/6]

[Christian Bruel]

[-- Attachment #1: Type: text/plain, Size: 572 bytes --]

Hi,

Commited [4/6] as attached (r224314)

thanks

Christian

On 06/08/2015 11:26 AM, Ramana Radhakrishnan wrote:
>
>
> On 08/06/15 09:45, Christian Bruel wrote:
>> Hi Ramana,
>>
>>>
>>> Ok, I see.
>>> The patch looks ok to me modulo the typo nits I pointed out, but I
>>> think Ramana
>>> should have the final say here as he's already started reviewing it
>>> and it adds quite
>>> a lot of functionality.
>>>
>>> Thanks,
>>> Kyrill
>>>
>>
>> do you have other feedbacks for the remaining parts ?
>>
>> many thanks
>>
>> Christian
>
>
> This is OK, thanks.
>
> Ramana
>

[-- Attachment #2: commited.txt --]
[-- Type: text/plain, Size: 21594 bytes --]

Index: gcc/doc/extend.texi
===================================================================
--- gcc/doc/extend.texi	(revision 224313)
+++ gcc/doc/extend.texi	(revision 224314)
@@ -3098,8 +3098,9 @@
 or separate the options with a comma (@samp{,}) within a single string.
 
 The options supported are specific to each target; refer to @ref{x86
-Function Attributes}, @ref{PowerPC Function Attributes}, and
-@ref{Nios II Function Attributes}, for details.
+Function Attributes}, @ref{PowerPC Function Attributes},
+@ref{ARM Function Attributes},and @ref{Nios II Function Attributes},
+for details.
 
 @item unused
 @cindex @code{unused} function attribute
@@ -3448,8 +3449,29 @@
 
 Variadic functions always use the @code{"aapcs"} calling convention and
 the compiler rejects attempts to specify an alternative.
+
+@item target (@var{options})
+@cindex @code{target} function attribute
+As discussed in @ref{Common Function Attributes}, this attribute 
+allows specification of target-specific compilation options.
+
+On ARM, the following options are allowed:
+
+@table @samp
+@item thumb
+@cindex @code{target("thumb")} function attribute, ARM
+Force code generation in the Thumb (T16/T32) ISA, depending on the
+architecture level.
+
+@item arm
+@cindex @code{target("arm")} function attribute, ARM
+Force code generation in the ARM (A32) ISA.
 @end table
 
+Functions from different modes can be inlined in the caller's mode.
+
+@end table
+
 @node AVR Function Attributes
 @subsection AVR Function Attributes
 
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 224313)
+++ gcc/doc/invoke.texi	(revision 224314)
@@ -13512,6 +13512,10 @@
 configuring GCC with the @option{--with-mode=}@var{state}
 configure option.
 
+You can also override the ARM and Thumb mode for each function
+by using the @code{target("thumb")} and @code{target("arm")} function attributes
+(@pxref{ARM Function Attributes}) or pragmas (@pxref{Function Specific Option Pragmas}).
+
 @item -mtpcs-frame
 @opindex mtpcs-frame
 Generate a stack frame that is compliant with the Thumb Procedure Call
Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog	(revision 224313)
+++ gcc/ChangeLog	(revision 224314)
@@ -1,3 +1,28 @@
+2015-06-09  Christian Bruel  <christian.bruel@st.com>
+
+	PR target/52144
+	* config/arm/arm.opt (THUMB, arm_restrict_it, inline_asm_unified): Save.
+	* config/arm/arm-protos.h (arm_valid_target_attribute_tree): Declare.
+	(arm_reset_previous_fndecl, arm_change_mode_p): Likewise.
+	* config/arm/arm.h (SWITCHABLE_TARGET): Define.
+	* config/arm/arm.c (arm_reset_previous_fndecl): New functions.
+	(arm_valid_target_attribute_tree, arm_change_mode_p): Likewise.
+	(arm_valid_target_attribute_p): Likewise.
+	(arm_set_current_function, arm_can_inline_p): Likewise.
+	(arm_valid_target_attribute_rec): Likewise.
+	(arm_previous_fndecl): New variable.
+	(TARGET_SET_CURRENT_FUNCTION, TARGET_OPTION_VALID_ATTRIBUTE_P): Define.
+	(TARGET_CAN_INLINE_P): Define.
+	(arm_asm_trampoline_template): Emit mode.
+	(arm_file_start): Don't set unified syntax.
+	(arm_declare_function_name): Set unified syntax and mode.
+	(arm_option_override): Init target_option_default_node.
+	and target_option_current_node.
+	* config/arm/arm.md (*call_value_symbol): Set mode when possible.
+	(*call_symbol): Likewise.
+	* doc/extend.texi: Document ARM/Thumb target attribute.
+	* doc/invoke.texi: Likewise.
+
 2015-06-09  Alexandre Oliva <aoliva@redhat.com>
 
 	Revert:
Index: gcc/testsuite/gcc.target/arm/attr_arm-err.c
===================================================================
--- gcc/testsuite/gcc.target/arm/attr_arm-err.c	(revision 0)
+++ gcc/testsuite/gcc.target/arm/attr_arm-err.c	(revision 224314)
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is rejected for M profile.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-march=*" } { "-march=armv6-m" } } */
+/* { dg-add-options arm_arch_v6m } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{  /* { dg-error "does not support" } */
+  return a ? 1 : 5;
+}
+
+
Index: gcc/testsuite/gcc.target/arm/attr_thumb.c
===================================================================
--- gcc/testsuite/gcc.target/arm/attr_thumb.c	(revision 0)
+++ gcc/testsuite/gcc.target/arm/attr_thumb.c	(revision 224314)
@@ -0,0 +1,13 @@
+/* Check that attribute target thumb is recogniwed. */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_thumb2_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".thumb" } } */
+/* { dg-final { scan-assembler "ite" } } */
+
+int __attribute__((target("thumb")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
Index: gcc/testsuite/gcc.target/arm/attr_thumb-static.c
===================================================================
--- gcc/testsuite/gcc.target/arm/attr_thumb-static.c	(revision 0)
+++ gcc/testsuite/gcc.target/arm/attr_thumb-static.c	(revision 224314)
@@ -0,0 +1,24 @@
+/* Check that a change mode to a static function is correctly handled. */
+/* { dg-do run } */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+static void
+ __attribute__((__noinline__)) 
+foo (void)
+{
+  __asm__ ("");
+}
+
+static void
+__attribute__((__noinline__)) 
+__attribute__((target("thumb")))
+bar (void)
+{
+  __asm__ ("");
+}
+
+int main()
+{
+  foo();
+  bar();
+}
Index: gcc/testsuite/gcc.target/arm/attr_arm.c
===================================================================
--- gcc/testsuite/gcc.target/arm/attr_arm.c	(revision 0)
+++ gcc/testsuite/gcc.target/arm/attr_arm.c	(revision 224314)
@@ -0,0 +1,13 @@
+/* Check that attribute target arm is recogniwed.  */
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler ".arm" } } */
+/* { dg-final { scan-assembler-not "ite" } } */
+
+int __attribute__((target("arm")))
+foo(int a)
+{
+  return a ? 1 : 5;
+}
+
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog	(revision 224313)
+++ gcc/testsuite/ChangeLog	(revision 224314)
@@ -1,3 +1,11 @@
+2015-06-09  Christian Bruel  <christian.bruel@st.com>
+
+	PR target/52144
+	* gcc.target/arm/attr_arm.c: New test
+	* gcc.target/arm/attr_arm-err.c: New test
+	* gcc.target/arm/attr_thumb.c: New test
+	* gcc.target/arm/attr_thumb-static.c: New test
+
 2015-06-10  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
 
 	PR target/66200
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c	(revision 224313)
+++ gcc/config/arm/arm.c	(revision 224314)
@@ -81,6 +81,7 @@
 #include "opts.h"
 #include "dumpfile.h"
 #include "gimple-expr.h"
+#include "target-globals.h"
 #include "builtins.h"
 #include "tm-constrs.h"
 #include "rtl-iter.h"
@@ -252,6 +253,9 @@
 static void arm_expand_builtin_va_start (tree, rtx);
 static tree arm_gimplify_va_arg_expr (tree, tree, gimple_seq *, gimple_seq *);
 static void arm_option_override (void);
+static void arm_set_current_function (tree);
+static bool arm_can_inline_p (tree, tree);
+static bool arm_valid_target_attribute_p (tree, tree, tree, int);
 static unsigned HOST_WIDE_INT arm_shift_truncation_mask (machine_mode);
 static bool arm_macro_fusion_p (void);
 static bool arm_cannot_copy_insn_p (rtx_insn *);
@@ -400,6 +404,9 @@
 #undef  TARGET_ASM_FUNCTION_EPILOGUE
 #define TARGET_ASM_FUNCTION_EPILOGUE arm_output_function_epilogue
 
+#undef TARGET_CAN_INLINE_P
+#define TARGET_CAN_INLINE_P arm_can_inline_p
+
 #undef  TARGET_OPTION_OVERRIDE
 #define TARGET_OPTION_OVERRIDE arm_option_override
 
@@ -418,6 +425,12 @@
 #undef  TARGET_SCHED_ADJUST_COST
 #define TARGET_SCHED_ADJUST_COST arm_adjust_cost
 
+#undef TARGET_SET_CURRENT_FUNCTION
+#define TARGET_SET_CURRENT_FUNCTION arm_set_current_function
+
+#undef TARGET_OPTION_VALID_ATTRIBUTE_P
+#define TARGET_OPTION_VALID_ATTRIBUTE_P arm_valid_target_attribute_p
+
 #undef TARGET_SCHED_REORDER
 #define TARGET_SCHED_REORDER arm_sched_reorder
 
@@ -2778,6 +2791,9 @@
     max_insns_skipped = current_tune->max_insns_skipped;
 }
 
+/* Options after initial target override.  */
+static GTY(()) tree init_optimize;
+
 /* Reset options between modes that the user has specified.  */
 static void
 arm_option_override_internal (struct gcc_options *opts,
@@ -2800,6 +2816,10 @@
   if (TARGET_THUMB_P (opts->x_target_flags) && TARGET_CALLEE_INTERWORKING)
     opts->x_target_flags |= MASK_INTERWORK;
 
+  /* need to remember initial values so combinaisons of options like
+     -mflip-thumb -mthumb -fno-schedule-insns work for any attribute.  */
+  cl_optimization *to = TREE_OPTIMIZATION (init_optimize);
+
   if (! opts_set->x_arm_restrict_it)
     opts->x_arm_restrict_it = arm_arch8;
 
@@ -2806,11 +2826,11 @@
   if (!TARGET_THUMB2_P (opts->x_target_flags))
     opts->x_arm_restrict_it = 0;
 
+  /* Don't warn since it's on by default in -O2.  */
   if (TARGET_THUMB1_P (opts->x_target_flags))
-    {
-      /* Don't warn since it's on by default in -O2.  */
-      opts->x_flag_schedule_insns = 0;
-    }
+    opts->x_flag_schedule_insns = 0;
+  else
+    opts->x_flag_schedule_insns = to->x_flag_schedule_insns;
 
   /* Disable shrink-wrap when optimizing function for size, since it tends to
      generate additional returns.  */
@@ -2817,6 +2837,8 @@
   if (optimize_function_for_size_p (cfun)
       && TARGET_THUMB2_P (opts->x_target_flags))
     opts->x_flag_shrink_wrap = false;
+  else
+    opts->x_flag_shrink_wrap = to->x_flag_shrink_wrap;
 
   /* In Thumb1 mode, we emit the epilogue in RTL, but the last insn
      - epilogue_insns - does not accurately model the corresponding insns
@@ -2828,6 +2850,8 @@
      fipa-ra.  */
   if (TARGET_THUMB1_P (opts->x_target_flags))
     opts->x_flag_ipa_ra = 0;
+  else
+    opts->x_flag_ipa_ra = to->x_flag_ipa_ra;
 
   /* Thumb2 inline assembly code should always use unified syntax.
      This will apply to ARM and Thumb1 eventually.  */
@@ -3330,6 +3354,9 @@
       && (!arm_arch7 || !current_tune->prefer_ldrd_strd))
     flag_schedule_fusion = 0;
 
+  /* Need to remember initial options before they are overriden.  */
+  init_optimize = build_optimization_node (&global_options);
+
   arm_option_override_internal (&global_options, &global_options_set);
   arm_option_check_internal (&global_options);
   arm_option_params_internal (&global_options);
@@ -3336,6 +3363,11 @@
 
   /* Register global variables with the garbage collector.  */
   arm_add_gc_roots ();
+
+  /* Save the initial options in case the user does function specific
+     options.  */
+  target_option_default_node = target_option_current_node
+    = build_target_option_node (&global_options);
 }
 
 static void
@@ -3489,13 +3521,20 @@
 static void
 arm_asm_trampoline_template (FILE *f)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (f, "\t.syntax unified\n");
+  else
+    fprintf (f, "\t.syntax divided\n");
+
   if (TARGET_ARM)
     {
+      fprintf (f, "\t.arm\n");
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", STATIC_CHAIN_REGNUM, PC_REGNUM);
       asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", PC_REGNUM, PC_REGNUM);
     }
   else if (TARGET_THUMB2)
     {
+      fprintf (f, "\t.thumb\n");
       /* The Thumb-2 trampoline is similar to the arm implementation.
 	 Unlike 16-bit Thumb, we enter the stub in thumb mode.  */
       asm_fprintf (f, "\tldr.w\t%r, [%r, #4]\n",
@@ -24193,7 +24232,25 @@
     mark_reg_pointer (arg_pointer_rtx, PARM_BOUNDARY);
 }
 
+/* Check that FUNC is called with a different mode.  */
 
+bool
+arm_change_mode_p (tree func)
+{
+  if (TREE_CODE (func) != FUNCTION_DECL)
+    return false;
+
+  tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (func);
+
+  if (!callee_tree)
+    callee_tree = target_option_default_node;
+
+  struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
+  int flags = callee_opts->x_target_flags;
+
+  return (TARGET_THUMB_P (flags) != TARGET_THUMB);
+}
+
 /* Like arm_compute_initial_elimination offset.  Simpler because there
    isn't an ABI specified frame pointer for Thumb.  Instead, we set it
    to point at the base of the local variables after static stack
@@ -25520,9 +25577,6 @@
 {
   int val;
 
-  if (TARGET_UNIFIED_ASM)
-    asm_fprintf (asm_out_file, "\t.syntax unified\n");
-
   if (TARGET_BPABI)
     {
       const char *fpu_name;
@@ -29269,9 +29323,196 @@
 	  && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)));
 }
 
+/* Remember the last target of arm_set_current_function.  */
+static GTY(()) tree arm_previous_fndecl;
+
+/* Invalidate arm_previous_fndecl.  */
 void
+arm_reset_previous_fndecl (void)
+{
+  arm_previous_fndecl = NULL_TREE;
+}
+
+/* Establish appropriate back-end context for processing the function
+   FNDECL.  The argument might be NULL to indicate processing at top
+   level, outside of any function scope.  */
+static void
+arm_set_current_function (tree fndecl)
+{
+  if (!fndecl || fndecl == arm_previous_fndecl)
+    return;
+
+  tree old_tree = (arm_previous_fndecl
+		   ? DECL_FUNCTION_SPECIFIC_TARGET (arm_previous_fndecl)
+		   : NULL_TREE);
+
+  tree new_tree = DECL_FUNCTION_SPECIFIC_TARGET (fndecl);
+
+  arm_previous_fndecl = fndecl;
+  if (old_tree == new_tree)
+    ;
+
+  else if (new_tree)
+    {
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  else if (old_tree)
+    {
+      new_tree = target_option_current_node;
+
+      cl_target_option_restore (&global_options,
+				TREE_TARGET_OPTION (new_tree));
+      if (TREE_TARGET_GLOBALS (new_tree))
+	restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+      else if (new_tree == target_option_default_node)
+	restore_target_globals (&default_target_globals);
+      else
+	TREE_TARGET_GLOBALS (new_tree)
+	  = save_target_globals_default_opts ();
+    }
+
+  arm_option_params_internal (&global_options);
+}
+
+/* Hook to determine if one function can safely inline another.  */
+
+static bool
+arm_can_inline_p (tree caller ATTRIBUTE_UNUSED, tree callee ATTRIBUTE_UNUSED)
+{
+  /* Overidde default hook: Always OK to inline between different modes. 
+     Function with mode specific instructions, e.g using asm, must be explicitely 
+     protected with noinline.  */
+  return true;
+}
+
+/* Inner function to process the attribute((target(...))), take an argument and
+   set the current options from the argument.  If we have a list, recursively
+   go over the list.  */
+
+static bool
+arm_valid_target_attribute_rec (tree args,  struct gcc_options *opts)
+{
+  if (TREE_CODE (args) == TREE_LIST)
+    {
+      bool ret = true;
+      for (; args; args = TREE_CHAIN (args))
+	if (TREE_VALUE (args)
+	    && !arm_valid_target_attribute_rec (TREE_VALUE (args), opts))
+	  ret = false;
+      return ret;
+    }
+
+  else if (TREE_CODE (args) != STRING_CST)
+    {
+      error ("attribute %<target%> argument not a string");
+      return false;
+    }
+
+  char *argstr = ASTRDUP (TREE_STRING_POINTER (args));
+  while (argstr && *argstr != '\0')
+    {
+      while (ISSPACE (*argstr))
+	argstr++;
+
+      if (!strcmp (argstr, "thumb"))
+	{
+	  opts->x_target_flags |= MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      if (!strcmp (argstr, "arm"))
+	{
+	  opts->x_target_flags &= ~MASK_THUMB;
+	  arm_option_check_internal (opts);
+	  return true;
+	}
+
+      warning (0, "attribute(target(\"%s\")) is unknown", argstr);
+      return false;
+    }
+
+  return false;
+}
+
+/* Return a TARGET_OPTION_NODE tree of the target options listed or NULL.  */
+
+tree
+arm_valid_target_attribute_tree (tree args, struct gcc_options *opts,
+				 struct gcc_options *opts_set)
+{
+  if (!arm_valid_target_attribute_rec (args, opts))
+    return NULL_TREE;
+
+  /* Do any overrides, such as global options arch=xxx.  */
+  arm_option_override_internal (opts, opts_set);
+
+  return build_target_option_node (opts);
+}
+
+/* Hook to validate attribute((target("string"))).  */
+
+static bool
+arm_valid_target_attribute_p (tree fndecl, tree ARG_UNUSED (name),
+			      tree args, int ARG_UNUSED (flags))
+{
+  bool ret = true;
+  struct gcc_options func_options;
+  tree cur_tree, new_optimize;
+  gcc_assert ((fndecl != NULL_TREE) && (args != NULL_TREE));
+
+  /* Get the optimization options of the current function.  */
+  tree func_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl);
+
+  /* If the function changed the optimization levels as well as setting target
+     options, start with the optimizations specified.  */
+  if (!func_optimize)
+    func_optimize = optimization_default_node;
+
+  /* Init func_options.  */
+  memset (&func_options, 0, sizeof (func_options));
+  init_options_struct (&func_options, NULL);
+  lang_hooks.init_options_struct (&func_options);
+
+  /* Initialize func_options to the defaults.  */
+  cl_optimization_restore (&func_options,
+			   TREE_OPTIMIZATION (func_optimize));
+
+  cl_target_option_restore (&func_options,
+			    TREE_TARGET_OPTION (target_option_default_node));
+
+  /* Set func_options flags with new target mode.  */
+  cur_tree = arm_valid_target_attribute_tree (args, &func_options,
+					      &global_options_set);
+
+  if (cur_tree == NULL_TREE)
+    ret = false;
+
+  new_optimize = build_optimization_node (&func_options);
+
+  DECL_FUNCTION_SPECIFIC_TARGET (fndecl) = cur_tree;
+
+  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (fndecl) = new_optimize;
+
+  return ret;
+}
+
+void
 arm_declare_function_name (FILE *stream, const char *name, tree decl)
 {
+  if (TARGET_UNIFIED_ASM)
+    fprintf (stream, "\t.syntax unified\n");
+  else
+    fprintf (stream, "\t.syntax divided\n");
+
   if (TARGET_THUMB)
     {
       if (is_called_in_ARM_mode (decl)
@@ -29283,6 +29524,8 @@
       else
 	fprintf (stream, "\t.thumb\n\t.thumb_func\n");
     }
+  else
+    fprintf (stream, "\t.arm\n");
 
   if (TARGET_POKE_FUNCTION_NAME)
     arm_poke_function_name (stream, (const char *) name);
Index: gcc/config/arm/arm.h
===================================================================
--- gcc/config/arm/arm.h	(revision 224313)
+++ gcc/config/arm/arm.h	(revision 224314)
@@ -2258,4 +2258,8 @@
 
 #define DRIVER_SELF_SPECS MCPU_MTUNE_NATIVE_SPECS
 #define TARGET_SUPPORTS_WIDE_INT 1
+
+/* For switching between functions with different target attributes.  */
+#define SWITCHABLE_TARGET 1
+
 #endif /* ! GCC_ARM_H */
Index: gcc/config/arm/arm-protos.h
===================================================================
--- gcc/config/arm/arm-protos.h	(revision 224313)
+++ gcc/config/arm/arm-protos.h	(revision 224314)
@@ -210,6 +210,9 @@
 extern int arm_dllimport_p (tree);
 extern void arm_mark_dllexport (tree);
 extern void arm_mark_dllimport (tree);
+extern bool arm_change_mode_p (tree);
+extern tree arm_valid_target_attribute_tree (tree, struct gcc_options *,
+					     struct gcc_options *);
 #endif
 
 extern void arm_pr_long_calls (struct cpp_reader *);
@@ -326,6 +329,8 @@
 
 extern void arm_emit_eabi_attribute (const char *, int, int);
 
+extern void arm_reset_previous_fndecl (void);
+
 /* Defined in gcc/common/config/arm-common.c.  */
 extern const char *arm_rewrite_selected_cpu (const char *name);
 
Index: gcc/config/arm/arm.opt
===================================================================
--- gcc/config/arm/arm.opt	(revision 224313)
+++ gcc/config/arm/arm.opt	(revision 224314)
@@ -182,7 +182,7 @@
 Specify the minimum bit alignment of structures
 
 mthumb
-Target Report RejectNegative Mask(THUMB)
+Target Report RejectNegative Mask(THUMB) Save
 Generate code for Thumb state
 
 mthumb-interwork
@@ -246,7 +246,7 @@
 Only generate absolute relocations on word sized values.
 
 mrestrict-it
-Target Report Var(arm_restrict_it) Init(2)
+Target Report Var(arm_restrict_it) Init(2) Save
 Generate IT blocks appropriate for ARMv8.
 
 mold-rtx-costs
@@ -275,5 +275,5 @@
 Assume loading data from flash is slower than fetching instructions.
 
 masm-syntax-unified
-Target Report Var(inline_asm_unified) Init(0)
+Target Report Var(inline_asm_unified) Init(0) Save
 Assume unified syntax for Thumb inline assembly code.
Index: gcc/config/arm/arm.md
===================================================================
--- gcc/config/arm/arm.md	(revision 224313)
+++ gcc/config/arm/arm.md	(revision 224314)
@@ -7787,6 +7787,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[0]))"
   "*
   {
+   rtx op = operands[0];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a0(PLT)\" : \"bl%?\\t%a0\";
   }"
   [(set_attr "type" "call")]
@@ -7804,6 +7811,13 @@
    && !arm_is_long_call_p (SYMBOL_REF_DECL (operands[1]))"
   "*
   {
+   rtx op = operands[1];
+
+   /* Switch mode now when possible.  */
+   if (SYMBOL_REF_DECL (op) && !TREE_PUBLIC (SYMBOL_REF_DECL (op))
+        && arm_arch5 && arm_change_mode_p (SYMBOL_REF_DECL (op)))
+      return NEED_PLT_RELOC ? \"blx%?\\t%a0(PLT)\" : \"blx%?\\t(%a0)\";
+
     return NEED_PLT_RELOC ? \"bl%?\\t%a1(PLT)\" : \"bl%?\\t%a1\";
   }"
   [(set_attr "type" "call")]

Re: [PATCH, ARM] (commited) attribute target (thumb,arm) [4/6]

[James Greenhalgh]

On Wed, Jun 10, 2015 at 08:57:37AM +0100, Christian Bruel wrote:
> Hi,
> 
> Commited [4/6] as attached (r224314)
> 
> thanks
> 
> Christian
> 
> On 06/08/2015 11:26 AM, Ramana Radhakrishnan wrote:
> > On 08/06/15 09:45, Christian Bruel wrote:
> >>
> >> do you have other feedbacks for the remaining parts ?
> >>
> >> many thanks
> >>
> >
> > This is OK, thanks.
> >
> > Ramana

Hi Christian,

This patch is causing an ICE for me in my arm-none-linux-gnueabihf testing.
It looks like something isn't saving/restoring/initialising data
structures needed for IRA.

I've raised https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66541 , the bug
looks very similar to pr64047
( https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64047 ).

Thanks,
James

---
.../gcc/cc1 bug.c -O2  -ftree-parallelize-loops=4  -O2 -flto  -fno-use-linker-plugin  -ftree-parallelize-loops=4 -o pr52429.s

 foo
Analyzing compilation unit
Performing interprocedural optimizations
 <*free_lang_data> <visibility> <build_ssa_passes> <opt_local_passes> <free-inline-summary> <whole-program> <profile_estimate> <icf> <devirt> <cp> <inline> <pure-const> <static-var> <single-use> <comdats>Assembling functions:
 foo
.../gcc/testsuite/gcc.dg/torture/pr52429.c: In function ‘foo’:
.../gcc/testsuite/gcc.dg/torture/pr52429.c:11:1: internal compiler error: Segmentation fault
   int i;
 ^
0xafa15f crash_signal
	.../gcc/toplev.c:369
0x97c2b4 record_operand_costs
	.../gcc/ira-costs.c:1305
0x97c7a4 scan_one_insn
	.../gcc/ira-costs.c:1483
0x97c7a4 process_bb_for_costs
	.../gcc/ira-costs.c:1604
0x97d715 find_costs_and_classes
	.../gcc/ira-costs.c:1711
0x97ec3a ira_set_pseudo_classes(bool, _IO_FILE*)
	.../gcc/ira-costs.c:2245
0xffd743 alloc_global_sched_pressure_data
	.../gcc/haifa-sched.c:7119
0xffd743 sched_init()
	.../gcc/haifa-sched.c:7269
0xffebcf haifa_sched_init()
	.../gcc/haifa-sched.c:7281
0xaab8dc schedule_insns
	.../gcc/sched-rgn.c:3411
0xaac0b3 schedule_insns
	.../gcc/sched-rgn.c:3405
0xaac0b3 rest_of_handle_sched
	.../gcc/sched-rgn.c:3624
0xaac0b3 execute
	.../gcc/sched-rgn.c:3732
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

Re: [PATCH, ARM] (commited) attribute target (thumb,arm) [4/6]

[Christian Bruel]

On 06/15/2015 12:00 PM, James Greenhalgh wrote:
> On Wed, Jun 10, 2015 at 08:57:37AM +0100, Christian Bruel wrote:
>> Hi,
>>
>> Commited [4/6] as attached (r224314)
>>
>> thanks
>>
>> Christian
>>
>> On 06/08/2015 11:26 AM, Ramana Radhakrishnan wrote:
>>> On 08/06/15 09:45, Christian Bruel wrote:
>>>>
>>>> do you have other feedbacks for the remaining parts ?
>>>>
>>>> many thanks
>>>>
>>>
>>> This is OK, thanks.
>>>
>>> Ramana
>
> Hi Christian,
>
> This patch is causing an ICE for me in my arm-none-linux-gnueabihf testing.
> It looks like something isn't saving/restoring/initialising data
> structures needed for IRA.
>
> I've raised https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66541 , the bug
> looks very similar to pr64047
> ( https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64047 ).
>
> Thanks,
> James
>


Hi James,

OK, I'll have a look. pr52429.c is reported as UNSUPPORTED with my runs 
of arm-none-eabi (no threads), but I can reproduce with a manual run.

Cheers

Christian

> ---
> .../gcc/cc1 bug.c -O2  -ftree-parallelize-loops=4  -O2 -flto  -fno-use-linker-plugin  -ftree-parallelize-loops=4 -o pr52429.s
>
>   foo
> Analyzing compilation unit
> Performing interprocedural optimizations
>   <*free_lang_data> <visibility> <build_ssa_passes> <opt_local_passes> <free-inline-summary> <whole-program> <profile_estimate> <icf> <devirt> <cp> <inline> <pure-const> <static-var> <single-use> <comdats>Assembling functions:
>   foo
> .../gcc/testsuite/gcc.dg/torture/pr52429.c: In function ‘foo’:
> .../gcc/testsuite/gcc.dg/torture/pr52429.c:11:1: internal compiler error: Segmentation fault
>     int i;
>   ^
> 0xafa15f crash_signal
> 	.../gcc/toplev.c:369
> 0x97c2b4 record_operand_costs
> 	.../gcc/ira-costs.c:1305
> 0x97c7a4 scan_one_insn
> 	.../gcc/ira-costs.c:1483
> 0x97c7a4 process_bb_for_costs
> 	.../gcc/ira-costs.c:1604
> 0x97d715 find_costs_and_classes
> 	.../gcc/ira-costs.c:1711
> 0x97ec3a ira_set_pseudo_classes(bool, _IO_FILE*)
> 	.../gcc/ira-costs.c:2245
> 0xffd743 alloc_global_sched_pressure_data
> 	.../gcc/haifa-sched.c:7119
> 0xffd743 sched_init()
> 	.../gcc/haifa-sched.c:7269
> 0xffebcf haifa_sched_init()
> 	.../gcc/haifa-sched.c:7281
> 0xaab8dc schedule_insns
> 	.../gcc/sched-rgn.c:3411
> 0xaac0b3 schedule_insns
> 	.../gcc/sched-rgn.c:3405
> 0xaac0b3 rest_of_handle_sched
> 	.../gcc/sched-rgn.c:3624
> 0xaac0b3 execute
> 	.../gcc/sched-rgn.c:3732
> Please submit a full bug report,
> with preprocessed source if appropriate.
> Please include the complete backtrace with any bug report.
> See <http://gcc.gnu.org/bugs.html> for instructions.
>