Index: gcc/doc/tm.texi =================================================================== --- gcc/doc/tm.texi (revision 160360) +++ gcc/doc/tm.texi (working copy) @@ -11181,3 +11181,11 @@ value of @code{TARGET_CONST_ANCHOR} is a MIPS, where add-immediate takes a 16-bit signed value, @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value is zero, which disables this optimization. @end deftypevr + +@deftypefn {Target Hook} bool TARGET_WARN_FUNC_RETURN (void) +This hook should return @code{false} to suppress warning about missing +return statements or suspect @code{noreturn} attributes for the current +function. The is typically appropriate for functions declared with +@code{__attribute__((naked))}. +The default implementation always returns @code{true}. +@end deftypefn Index: gcc/target.h =================================================================== --- gcc/target.h (revision 160360) +++ gcc/target.h (working copy) @@ -1239,6 +1239,10 @@ struct gcc_target bits in the bitmap passed in. */ void (*live_on_entry) (bitmap); + /* Return false if warnings about missing return statements or suspect + noreturn attributes should be suppressed for the current function. */ + bool (*warn_func_return) (void); + /* True if unwinding tables should be generated by default. */ bool unwind_tables_default; Index: gcc/testsuite/gcc.target/arm/naked-3.c =================================================================== --- gcc/testsuite/gcc.target/arm/naked-3.c (revision 0) +++ gcc/testsuite/gcc.target/arm/naked-3.c (revision 0) @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -Wall" } */ +/* Check that we do not get warnings about missing return statements + or bogus looking noreturn functions. */ +int __attribute__((naked)) +foo(void) +{ + __asm__ volatile ("mov r0, #1\r\nbx lr\n"); +} + +int __attribute__((naked,noreturn)) +bar(void) +{ + __asm__ volatile ("frob r0\n"); +} Index: gcc/target-def.h =================================================================== --- gcc/target-def.h (revision 160360) +++ gcc/target-def.h (working copy) @@ -220,6 +220,10 @@ #define TARGET_EXTRA_LIVE_ON_ENTRY hook_void_bitmap #endif +#ifndef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN hook_bool_void_true +#endif + #ifndef TARGET_ASM_FILE_START_APP_OFF #define TARGET_ASM_FILE_START_APP_OFF false #endif @@ -1074,6 +1078,7 @@ TARGET_EMUTLS, \ TARGET_OPTION_HOOKS, \ TARGET_EXTRA_LIVE_ON_ENTRY, \ + TARGET_WARN_FUNC_RETURN, \ TARGET_UNWIND_TABLES_DEFAULT, \ TARGET_HAVE_NAMED_SECTIONS, \ TARGET_HAVE_SWITCHABLE_BSS_SECTIONS, \ Index: gcc/tree-cfg.c =================================================================== --- gcc/tree-cfg.c (revision 160360) +++ gcc/tree-cfg.c (working copy) @@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. #include "value-prof.h" #include "pointer-set.h" #include "tree-inline.h" +#include "target.h" /* This file contains functions for building the Control Flow Graph (CFG) for a function tree. */ @@ -7163,6 +7164,9 @@ execute_warn_function_return (void) edge e; edge_iterator ei; + if (!targetm.warn_func_return ()) + return 0; + /* If we have a path to EXIT, then we do return. */ if (TREE_THIS_VOLATILE (cfun->decl) && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0) Index: gcc/config/spu/spu.c =================================================================== --- gcc/config/spu/spu.c (revision 160360) +++ gcc/config/spu/spu.c (working copy) @@ -280,6 +280,8 @@ spu_libgcc_cmp_return_mode (void); static enum machine_mode spu_libgcc_shift_count_mode (void); +static bool spu_warn_func_return (void); + /* Pointer mode for __ea references. */ #define EAmode (spu_ea_model != 32 ? DImode : SImode) @@ -465,6 +467,9 @@ static const struct attribute_spec spu_a #undef TARGET_TRAMPOLINE_INIT #define TARGET_TRAMPOLINE_INIT spu_trampoline_init +#undef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN spu_warn_func_return + struct gcc_target targetm = TARGET_INITIALIZER; void @@ -7089,4 +7094,12 @@ spu_function_profiler (FILE * file, int fprintf (file, "brsl $75, _mcount\n"); } +static bool +spu_warn_func_return (void) +{ + /* Naked functions are implemented entirely in assembly, including the + return sequence, so suppress warnings about this. */ + return !spu_naked_function_p (current_function_decl); +} + #include "gt-spu.h" Index: gcc/config/rx/rx.c =================================================================== --- gcc/config/rx/rx.c (revision 160360) +++ gcc/config/rx/rx.c (working copy) @@ -2227,6 +2227,14 @@ rx_func_attr_inlinable (const_tree decl) && ! is_naked_func (decl); } +static bool +rx_warn_func_return (void) +{ + /* Naked functions are implemented entirely in assembly, including the + return sequence, so suppress warnings about this. */ + return !is_naked_func (NULL_TREE); +} + /* Return nonzero if it is ok to make a tail-call to DECL, a function_decl or NULL if this is an indirect call, using EXP */ @@ -2573,6 +2581,9 @@ rx_trampoline_init (rtx tramp, tree fnde #undef TARGET_TRAMPOLINE_INIT #define TARGET_TRAMPOLINE_INIT rx_trampoline_init +#undef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN rx_warn_func_return + struct gcc_target targetm = TARGET_INITIALIZER; /* #include "gt-rx.h" */ Index: gcc/config/avr/avr.c =================================================================== --- gcc/config/avr/avr.c (revision 160360) +++ gcc/config/avr/avr.c (working copy) @@ -90,6 +90,7 @@ static bool avr_hard_regno_scratch_ok (u static unsigned int avr_case_values_threshold (void); static bool avr_frame_pointer_required_p (void); static bool avr_can_eliminate (const int, const int); +static bool avr_warn_func_return (void); /* Allocate registers from r25 to r8 for parameters for function calls. */ #define FIRST_CUM_REG 26 @@ -191,6 +192,9 @@ static const struct attribute_spec avr_a #undef TARGET_CAN_ELIMINATE #define TARGET_CAN_ELIMINATE avr_can_eliminate +#undef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN avr_warn_func_return + struct gcc_target targetm = TARGET_INITIALIZER; void @@ -6144,4 +6148,12 @@ unsigned int avr_case_values_threshold ( return (!AVR_HAVE_JMP_CALL || TARGET_CALL_PROLOGUES) ? 8 : 17; } +static bool +avr_warn_func_return (void) +{ + /* Naked functions are implemented entirely in assembly, including the + return sequence, so suppress warnings about this. */ + return !avr_naked_function_p (current_function_decl); +} + #include "gt-avr.h" Index: gcc/config/mcore/mcore.c =================================================================== --- gcc/config/mcore/mcore.c (revision 160360) +++ gcc/config/mcore/mcore.c (working copy) @@ -145,6 +145,7 @@ static int mcore_arg_partial_byte tree, bool); static void mcore_asm_trampoline_template (FILE *); static void mcore_trampoline_init (rtx, tree, rtx); +static bool mcore_warn_func_return (void); /* MCore specific attributes. */ @@ -214,6 +215,9 @@ static const struct attribute_spec mcore #undef TARGET_TRAMPOLINE_INIT #define TARGET_TRAMPOLINE_INIT mcore_trampoline_init +#undef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN mcore_warn_func_return + struct gcc_target targetm = TARGET_INITIALIZER; /* Adjust the stack and return the number of bytes taken to do it. */ @@ -2557,9 +2561,6 @@ conditionalize_optimization (void) continue; } -static int saved_warn_return_type = -1; -static int saved_warn_return_type_count = 0; - /* This is to handle loads from the constant pool. */ static void @@ -2568,21 +2569,6 @@ mcore_reorg (void) /* Reset this variable. */ current_function_anonymous_args = 0; - /* Restore the warn_return_type if it has been altered. */ - if (saved_warn_return_type != -1) - { - /* Only restore the value if we have reached another function. - The test of warn_return_type occurs in final_function () in - c-decl.c a long time after the code for the function is generated, - so we need a counter to tell us when we have finished parsing that - function and can restore the flag. */ - if (--saved_warn_return_type_count == 0) - { - warn_return_type = saved_warn_return_type; - saved_warn_return_type = -1; - } - } - if (optimize == 0) return; @@ -3012,25 +2998,7 @@ static tree mcore_handle_naked_attribute (tree * node, tree name, tree args ATTRIBUTE_UNUSED, int flags ATTRIBUTE_UNUSED, bool * no_add_attrs) { - if (TREE_CODE (*node) == FUNCTION_DECL) - { - /* PR14310 - don't complain about lack of return statement - in naked functions. The solution here is a gross hack - but this is the only way to solve the problem without - adding a new feature to GCC. I did try submitting a patch - that would add such a new feature, but it was (rightfully) - rejected on the grounds that it was creeping featurism, - so hence this code. */ - if (warn_return_type) - { - saved_warn_return_type = warn_return_type; - warn_return_type = 0; - saved_warn_return_type_count = 2; - } - else if (saved_warn_return_type_count) - saved_warn_return_type_count = 2; - } - else + if (TREE_CODE (*node) != FUNCTION_DECL) { warning (OPT_Wattributes, "%qE attribute only applies to functions", name); @@ -3082,6 +3050,14 @@ mcore_naked_function_p (void) return lookup_attribute ("naked", DECL_ATTRIBUTES (current_function_decl)) != NULL_TREE; } +static bool +mcore_warn_func_return (void) +{ + /* Naked functions are implemented entirely in assembly, including the + return sequence, so suppress warnings about this. */ + return !mcore_naked_function_p (); +} + #ifdef OBJECT_FORMAT_ELF static void mcore_asm_named_section (const char *name, Index: gcc/config/arm/arm.c =================================================================== --- gcc/config/arm/arm.c (revision 160360) +++ gcc/config/arm/arm.c (working copy) @@ -212,6 +212,7 @@ static bool arm_tls_symbol_p (rtx x); static int arm_issue_rate (void); static void arm_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED; static bool arm_allocate_stack_slots_for_args (void); +static bool arm_warn_func_return (void); static const char *arm_invalid_parameter_type (const_tree t); static const char *arm_invalid_return_type (const_tree t); static tree arm_promoted_type (const_tree t); @@ -377,6 +378,9 @@ static const struct attribute_spec arm_a #undef TARGET_TRAMPOLINE_ADJUST_ADDRESS #define TARGET_TRAMPOLINE_ADJUST_ADDRESS arm_trampoline_adjust_address +#undef TARGET_WARN_FUNC_RETURN +#define TARGET_WARN_FUNC_RETURN arm_warn_func_return + #undef TARGET_DEFAULT_SHORT_ENUMS #define TARGET_DEFAULT_SHORT_ENUMS arm_default_short_enums @@ -1992,6 +1996,14 @@ arm_allocate_stack_slots_for_args (void) return !IS_NAKED (arm_current_func_type ()); } +static bool +arm_warn_func_return (void) +{ + /* Naked functions are implemented entirely in assembly, including the + return sequence, so suppress warnings about this. */ + return !IS_NAKED (arm_current_func_type ()); +} + /* Output assembler code for a block containing the constant parts of a trampoline, leaving space for the variable parts.