Add ARM/thumb attribute target

	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.

	* 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

From-SVN: r224314

gcc/ChangeLog

+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:

gcc/config/arm/arm-protos.h

@@ -210,6 +210,9 @@ extern int arm_dllexport_p (tree);
 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 bool arm_autoinc_modes_ok_p (machine_mode, enum arm_auto_incmodes);
 
 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);
 

gcc/config/arm/arm.h

@@ -2258,4 +2258,8 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
 
 #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 */

gcc/config/arm/arm.md

@@ -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")]

gcc/config/arm/arm.opt

@@ -182,7 +182,7 @@ Target RejectNegative Joined UInteger Var(arm_structure_size_boundary) Init(DEFA
 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 @@ Target Report Var(target_word_relocations) Init(TARGET_DEFAULT_WORD_RELOCATIONS)
 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 @@ Target Report Var(target_slow_flash_data) Init(0)
 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.

gcc/doc/extend.texi

@@ -3098,8 +3098,9 @@ strings separated by commas to specify multiple options,
 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
@@ -3448,6 +3449,27 @@ double f2d (float) __attribute__((pcs("aapcs")));
 
 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

gcc/doc/invoke.texi

@@ -13512,6 +13512,10 @@ that executes in ARM state, but the default can be changed by
 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

gcc/testsuite/ChangeLog

+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

gcc/testsuite/gcc.target/arm/attr_arm-err.c

+/* 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;
+}
+
+

gcc/testsuite/gcc.target/arm/attr_arm.c

+/* 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;
+}
+

gcc/testsuite/gcc.target/arm/attr_thumb-static.c

+/* 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();
+}

gcc/testsuite/gcc.target/arm/attr_thumb.c

+/* 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;
+}
+