Message ID | 1447758067-4440-1-git-send-email-hjl.tools@gmail.com |
---|---|
State | New |
Headers | show |
On Tue, Nov 17, 2015 at 12:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote: > Empty record should be returned and passed the same way in C and C++. > This patch adds LANG_HOOKS_EMPTY_RECORD_P for C++ empty class, which > defaults to return false. For C++, LANG_HOOKS_EMPTY_RECORD_P is defined > to is_really_empty_class, which returns true for C++ empty classes. For > LTO, we stream out a bit to indicate if a record is empty and we store > it in TYPE_LANG_FLAG_0 when streaming in. get_ref_base_and_extent is > changed to set bitsize to 0 for empty records. Middle-end and x86 > backend are updated to ignore empty records for parameter passing and > function value return. Other targets may need similar changes. Please avoid a new langhook for this and instead claim a bit in tree_type_common like for example restrict_flag (double-check it is unused for non-pointers). I don't like that you need to modify targets - those checks should be done in the caller (which may just use a new wrapper with the logic and then dispatching to the actual hook). Why do you need do adjust get_ref_base_and_extent? Thanks, Richard. > gcc/ > > PR c++/60336 > PR middle-end/67239 > PR target/68355 > * calls.c (store_one_arg): Use 0 for empty record size. Don't > push 0 size argument onto stack. > (must_pass_in_stack_var_size_or_pad): Return false for empty > record. > * function.c (locate_and_pad_parm): Use 0 for empty record size. > * tree-dfa.c (get_ref_base_and_extent): Likewise. > * langhooks-def.h (LANG_HOOKS_EMPTY_RECORD_P): New. > (LANG_HOOKS_DECLS): Add LANG_HOOKS_EMPTY_RECORD_P. > * langhooks.h (lang_hooks_for_decls): Add empty_record_p. > * lto-streamer.h (LTO_major_version): Increase by 1 to 6. > * targhooks.c: Include "langhooks.h". > (std_gimplify_va_arg_expr): Use 0 for empty record size. > * tree-streamer-in.c (unpack_ts_base_value_fields): Stream in > TYPE_LANG_FLAG_0. > * tree-streamer-out.c: Include "langhooks.h". > (pack_ts_base_value_fields): Stream out a bit to indicate if a > record is empty. > * config/i386/i386.c (classify_argument): Return 0 for empty > record. > (construct_container): Return NULL for empty record. > (ix86_function_arg): Likewise. > (ix86_function_arg_advance): Skip empty record. > (ix86_return_in_memory): Return false for empty record. > (ix86_gimplify_va_arg): Use 0 for empty record size. > > gcc/cp/ > > PR c++/60336 > PR middle-end/67239 > PR target/68355 > * class.c (is_empty_class): Changed to return bool and take > const_tree. > (is_really_empty_class): Changed to take const_tree. Check > if TYPE_BINFO is zero. > * cp-tree.h (is_empty_class): Updated. > (is_really_empty_class): Likewise. > * cp-lang.c (LANG_HOOKS_EMPTY_RECORD_P): New. > > gcc/lto/ > > PR c++/60336 > PR middle-end/67239 > PR target/68355 > * lto-lang.c (lto_empty_record_p): New. > (LANG_HOOKS_EMPTY_RECORD_P): Likewise. > > gcc/testsuite/ > > PR c++/60336 > PR middle-end/67239 > PR target/68355 > * g++.dg/abi/empty12.C: New test. > * g++.dg/abi/empty12.h: Likewise. > * g++.dg/abi/empty12a.c: Likewise. > * g++.dg/pr60336-1.C: Likewise. > * g++.dg/pr60336-2.C: Likewise. > * g++.dg/pr68355.C: Likewise. > --- > gcc/calls.c | 41 +++++++++++++++++++++++++++---------- > gcc/config/i386/i386.c | 18 +++++++++++++++- > gcc/cp/class.c | 17 ++++++++------- > gcc/cp/cp-lang.c | 2 ++ > gcc/cp/cp-tree.h | 4 ++-- > gcc/function.c | 7 +++++-- > gcc/langhooks-def.h | 2 ++ > gcc/langhooks.h | 3 +++ > gcc/lto-streamer.h | 2 +- > gcc/lto/lto-lang.c | 13 ++++++++++++ > gcc/targhooks.c | 6 +++++- > gcc/testsuite/g++.dg/abi/empty12.C | 17 +++++++++++++++ > gcc/testsuite/g++.dg/abi/empty12.h | 9 ++++++++ > gcc/testsuite/g++.dg/abi/empty12a.c | 6 ++++++ > gcc/testsuite/g++.dg/pr60336-1.C | 17 +++++++++++++++ > gcc/testsuite/g++.dg/pr60336-2.C | 28 +++++++++++++++++++++++++ > gcc/testsuite/g++.dg/pr68355.C | 24 ++++++++++++++++++++++ > gcc/tree-dfa.c | 2 ++ > gcc/tree-streamer-in.c | 5 +++++ > gcc/tree-streamer-out.c | 6 ++++++ > 20 files changed, 204 insertions(+), 25 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/abi/empty12.C > create mode 100644 gcc/testsuite/g++.dg/abi/empty12.h > create mode 100644 gcc/testsuite/g++.dg/abi/empty12a.c > create mode 100644 gcc/testsuite/g++.dg/pr60336-1.C > create mode 100644 gcc/testsuite/g++.dg/pr60336-2.C > create mode 100644 gcc/testsuite/g++.dg/pr68355.C > > diff --git a/gcc/calls.c b/gcc/calls.c > index b56556a..ecc9b7a 100644 > --- a/gcc/calls.c > +++ b/gcc/calls.c > @@ -4835,7 +4835,10 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, > Note that in C the default argument promotions > will prevent such mismatches. */ > > - size = GET_MODE_SIZE (arg->mode); > + if (lang_hooks.decls.empty_record_p (TREE_TYPE (pval))) > + size = 0; > + else > + size = GET_MODE_SIZE (arg->mode); > /* Compute how much space the push instruction will push. > On many machines, pushing a byte will advance the stack > pointer by a halfword. */ > @@ -4865,10 +4868,14 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, > > /* This isn't already where we want it on the stack, so put it there. > This can either be done with push or copy insns. */ > - if (!emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), NULL_RTX, > - parm_align, partial, reg, used - size, argblock, > - ARGS_SIZE_RTX (arg->locate.offset), reg_parm_stack_space, > - ARGS_SIZE_RTX (arg->locate.alignment_pad), true)) > + if (used > + && !emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), > + NULL_RTX, parm_align, partial, reg, > + used - size, argblock, > + ARGS_SIZE_RTX (arg->locate.offset), > + reg_parm_stack_space, > + ARGS_SIZE_RTX (arg->locate.alignment_pad), > + true)) > sibcall_failure = 1; > > /* Unless this is a partially-in-register argument, the argument is now > @@ -4900,10 +4907,16 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, > { > /* PUSH_ROUNDING has no effect on us, because emit_push_insn > for BLKmode is careful to avoid it. */ > + bool empty_record > + = lang_hooks.decls.empty_record_p (TREE_TYPE (pval)); > excess = (arg->locate.size.constant > - - int_size_in_bytes (TREE_TYPE (pval)) > + - (empty_record > + ? 0 > + : int_size_in_bytes (TREE_TYPE (pval))) > + partial); > - size_rtx = expand_expr (size_in_bytes (TREE_TYPE (pval)), > + size_rtx = expand_expr ((empty_record > + ? size_zero_node > + : size_in_bytes (TREE_TYPE (pval))), > NULL_RTX, TYPE_MODE (sizetype), > EXPAND_NORMAL); > } > @@ -4971,10 +4984,13 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, > } > } > > - emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), size_rtx, > - parm_align, partial, reg, excess, argblock, > - ARGS_SIZE_RTX (arg->locate.offset), reg_parm_stack_space, > - ARGS_SIZE_RTX (arg->locate.alignment_pad), false); > + if (!CONST_INT_P (size_rtx) || INTVAL (size_rtx) != 0) > + emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), > + size_rtx, parm_align, partial, reg, excess, > + argblock, ARGS_SIZE_RTX (arg->locate.offset), > + reg_parm_stack_space, > + ARGS_SIZE_RTX (arg->locate.alignment_pad), > + false); > > /* Unless this is a partially-in-register argument, the argument is now > in the stack. > @@ -5052,6 +5068,9 @@ must_pass_in_stack_var_size_or_pad (machine_mode mode, const_tree type) > if (TREE_ADDRESSABLE (type)) > return true; > > + if (lang_hooks.decls.empty_record_p (type)) > + return false; > + > /* If the padding and mode of the type is such that a copy into > a register would put it into the wrong part of the register. */ > if (mode == BLKmode > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c > index 6173dae..8bd6198 100644 > --- a/gcc/config/i386/i386.c > +++ b/gcc/config/i386/i386.c > @@ -7920,6 +7920,9 @@ static int > classify_argument (machine_mode mode, const_tree type, > enum x86_64_reg_class classes[MAX_CLASSES], int bit_offset) > { > + if (type && lang_hooks.decls.empty_record_p (type)) > + return 0; > + > HOST_WIDE_INT bytes = > (mode == BLKmode) ? int_size_in_bytes (type) : (int) GET_MODE_SIZE (mode); > int words = CEIL (bytes + (bit_offset % 64) / 8, UNITS_PER_WORD); > @@ -8371,6 +8374,9 @@ construct_container (machine_mode mode, machine_mode orig_mode, > static bool issued_sse_ret_error; > static bool issued_x87_ret_error; > > + if (type && lang_hooks.decls.empty_record_p (type)) > + return NULL; > + > machine_mode tmpmode; > int bytes = > (mode == BLKmode) ? int_size_in_bytes (type) : (int) GET_MODE_SIZE (mode); > @@ -8783,6 +8789,9 @@ ix86_function_arg_advance (cumulative_args_t cum_v, machine_mode mode, > HOST_WIDE_INT bytes, words; > int nregs; > > + if (type && lang_hooks.decls.empty_record_p (type)) > + return; > + > if (mode == BLKmode) > bytes = int_size_in_bytes (type); > else > @@ -9099,6 +9108,9 @@ ix86_function_arg (cumulative_args_t cum_v, machine_mode omode, > HOST_WIDE_INT bytes, words; > rtx arg; > > + if (type && lang_hooks.decls.empty_record_p (type)) > + return NULL; > + > /* All pointer bounds arguments are handled separately here. */ > if ((type && POINTER_BOUNDS_TYPE_P (type)) > || POINTER_BOUNDS_MODE_P (mode)) > @@ -9708,6 +9720,9 @@ ix86_return_in_memory (const_tree type, const_tree fntype ATTRIBUTE_UNUSED) > if (POINTER_BOUNDS_TYPE_P (type)) > return false; > > + if (type && lang_hooks.decls.empty_record_p (type)) > + return false; > + > if (TARGET_64BIT) > { > if (ix86_function_type_abi (fntype) == MS_ABI) > @@ -10266,7 +10281,8 @@ ix86_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p, > indirect_p = pass_by_reference (NULL, TYPE_MODE (type), type, false); > if (indirect_p) > type = build_pointer_type (type); > - size = int_size_in_bytes (type); > + bool empty_record = type && lang_hooks.decls.empty_record_p (type); > + size = empty_record ? 0 : int_size_in_bytes (type); > rsize = CEIL (size, UNITS_PER_WORD); > > nat_mode = type_natural_mode (type, NULL, false); > diff --git a/gcc/cp/class.c b/gcc/cp/class.c > index 216a301..c380734 100644 > --- a/gcc/cp/class.c > +++ b/gcc/cp/class.c > @@ -8068,8 +8068,8 @@ build_self_reference (void) > > /* Returns 1 if TYPE contains only padding bytes. */ > > -int > -is_empty_class (tree type) > +bool > +is_empty_class (const_tree type) > { > if (type == error_mark_node) > return 0; > @@ -8084,7 +8084,7 @@ is_empty_class (tree type) > possible combinations of empty classes and possibly a vptr. */ > > bool > -is_really_empty_class (tree type) > +is_really_empty_class (const_tree type) > { > if (CLASS_TYPE_P (type)) > { > @@ -8098,10 +8098,13 @@ is_really_empty_class (tree type) > if (COMPLETE_TYPE_P (type) && is_empty_class (type)) > return true; > > - for (binfo = TYPE_BINFO (type), i = 0; > - BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i) > - if (!is_really_empty_class (BINFO_TYPE (base_binfo))) > - return false; > + /* TYPE_BINFO may be zeron when is_really_empty_class is called > + from LANG_HOOKS_EMPTY_RECORD_P. */ > + binfo = TYPE_BINFO (type); > + if (binfo) > + for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i) > + if (!is_really_empty_class (BINFO_TYPE (base_binfo))) > + return false; > for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) > if (TREE_CODE (field) == FIELD_DECL > && !DECL_ARTIFICIAL (field) > diff --git a/gcc/cp/cp-lang.c b/gcc/cp/cp-lang.c > index 048108d..80174cb 100644 > --- a/gcc/cp/cp-lang.c > +++ b/gcc/cp/cp-lang.c > @@ -78,6 +78,8 @@ static tree cxx_enum_underlying_base_type (const_tree); > #define LANG_HOOKS_EH_RUNTIME_TYPE build_eh_type_type > #undef LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE > #define LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE cxx_enum_underlying_base_type > +#undef LANG_HOOKS_EMPTY_RECORD_P > +#define LANG_HOOKS_EMPTY_RECORD_P is_really_empty_class > > /* Each front end provides its own lang hook initializer. */ > struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER; > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 84437b4..dc79979 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -5578,8 +5578,8 @@ extern tree finish_struct (tree, tree); > extern void finish_struct_1 (tree); > extern int resolves_to_fixed_type_p (tree, int *); > extern void init_class_processing (void); > -extern int is_empty_class (tree); > -extern bool is_really_empty_class (tree); > +extern bool is_empty_class (const_tree); > +extern bool is_really_empty_class (const_tree); > extern void pushclass (tree); > extern void popclass (void); > extern void push_nested_class (tree); > diff --git a/gcc/function.c b/gcc/function.c > index afc2c87..b59157d 100644 > --- a/gcc/function.c > +++ b/gcc/function.c > @@ -4093,8 +4093,11 @@ locate_and_pad_parm (machine_mode passed_mode, tree type, int in_regs, > > part_size_in_regs = (reg_parm_stack_space == 0 ? partial : 0); > > - sizetree > - = type ? size_in_bytes (type) : size_int (GET_MODE_SIZE (passed_mode)); > + if (type) > + sizetree = (lang_hooks.decls.empty_record_p (type) > + ? size_zero_node : size_in_bytes (type)); > + else > + sizetree = size_int (GET_MODE_SIZE (passed_mode)); > where_pad = FUNCTION_ARG_PADDING (passed_mode, type); > boundary = targetm.calls.function_arg_boundary (passed_mode, type); > round_boundary = targetm.calls.function_arg_round_boundary (passed_mode, > diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h > index 18ac84d..df4cbf8 100644 > --- a/gcc/langhooks-def.h > +++ b/gcc/langhooks-def.h > @@ -163,6 +163,7 @@ extern tree lhd_make_node (enum tree_code); > #define LANG_HOOKS_GENERIC_GENERIC_PARAMETER_DECL_P hook_bool_const_tree_false > #define LANG_HOOKS_FUNCTION_PARM_EXPANDED_FROM_PACK_P \ > hook_bool_tree_tree_false > +#define LANG_HOOKS_EMPTY_RECORD_P hook_bool_const_tree_false > #define LANG_HOOKS_GET_GENERIC_FUNCTION_DECL hook_tree_const_tree_null > #define LANG_HOOKS_TYPE_PROMOTES_TO lhd_type_promotes_to > #define LANG_HOOKS_REGISTER_BUILTIN_TYPE lhd_register_builtin_type > @@ -228,6 +229,7 @@ extern tree lhd_make_node (enum tree_code); > LANG_HOOKS_FUNCTION_DECL_DELETED_P, \ > LANG_HOOKS_GENERIC_GENERIC_PARAMETER_DECL_P, \ > LANG_HOOKS_FUNCTION_PARM_EXPANDED_FROM_PACK_P, \ > + LANG_HOOKS_EMPTY_RECORD_P, \ > LANG_HOOKS_GET_GENERIC_FUNCTION_DECL, \ > LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL, \ > LANG_HOOKS_POST_COMPILATION_PARSING_CLEANUPS, \ > diff --git a/gcc/langhooks.h b/gcc/langhooks.h > index d8d01fa..450bdee 100644 > --- a/gcc/langhooks.h > +++ b/gcc/langhooks.h > @@ -177,6 +177,9 @@ struct lang_hooks_for_decls > function parameter pack. */ > bool (*function_parm_expanded_from_pack_p) (tree, tree); > > + /* Determine if a type is an empty record. */ > + bool (*empty_record_p) (const_tree type); > + > /* Returns the generic declaration of a generic function instantiations. */ > tree (*get_generic_function_decl) (const_tree); > > diff --git a/gcc/lto-streamer.h b/gcc/lto-streamer.h > index 5aae9e9..cc4cede 100644 > --- a/gcc/lto-streamer.h > +++ b/gcc/lto-streamer.h > @@ -128,7 +128,7 @@ along with GCC; see the file COPYING3. If not see > String are represented in the table as pairs, a length in ULEB128 > form followed by the data for the string. */ > > -#define LTO_major_version 5 > +#define LTO_major_version 6 > #define LTO_minor_version 0 > > typedef unsigned char lto_decl_flags_t; > diff --git a/gcc/lto/lto-lang.c b/gcc/lto/lto-lang.c > index 53dd8f6..dc849a4 100644 > --- a/gcc/lto/lto-lang.c > +++ b/gcc/lto/lto-lang.c > @@ -1306,6 +1306,16 @@ static void lto_init_ts (void) > tree_contains_struct[NAMESPACE_DECL][TS_DECL_MINIMAL] = 1; > } > > +/* Return true if TYPE contains no actual data, just various possible > + combinations of empty records. */ > + > +static bool > +lto_empty_record_p (const_tree type) > +{ > + /* Set if a record is empty. */ > + return TYPE_LANG_FLAG_0 (type); > +} > + > #undef LANG_HOOKS_NAME > #define LANG_HOOKS_NAME "GNU GIMPLE" > #undef LANG_HOOKS_OPTION_LANG_MASK > @@ -1363,6 +1373,9 @@ static void lto_init_ts (void) > #undef LANG_HOOKS_INIT_TS > #define LANG_HOOKS_INIT_TS lto_init_ts > > +#undef LANG_HOOKS_EMPTY_RECORD_P > +#define LANG_HOOKS_EMPTY_RECORD_P lto_empty_record_p > + > struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER; > > /* Language hooks that are not part of lang_hooks. */ > diff --git a/gcc/targhooks.c b/gcc/targhooks.c > index c34b4e9..5e74dd9 100644 > --- a/gcc/targhooks.c > +++ b/gcc/targhooks.c > @@ -74,6 +74,7 @@ along with GCC; see the file COPYING3. If not see > #include "intl.h" > #include "opts.h" > #include "gimplify.h" > +#include "langhooks.h" > > > bool > @@ -1823,9 +1824,12 @@ std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p, > /* Hoist the valist value into a temporary for the moment. */ > valist_tmp = get_initialized_tmp_var (valist, pre_p, NULL); > > + bool empty_record = lang_hooks.decls.empty_record_p (type); > + > /* va_list pointer is aligned to PARM_BOUNDARY. If argument actually > requires greater alignment, we must perform dynamic alignment. */ > if (boundary > align > + && !empty_record > && !integer_zerop (TYPE_SIZE (type))) > { > t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp, > @@ -1852,7 +1856,7 @@ std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p, > } > > /* Compute the rounded size of the type. */ > - type_size = size_in_bytes (type); > + type_size = empty_record ? size_zero_node : size_in_bytes (type); > rounded_size = round_up (type_size, align); > > /* Reduce rounded_size so it's sharable with the postqueue. */ > diff --git a/gcc/testsuite/g++.dg/abi/empty12.C b/gcc/testsuite/g++.dg/abi/empty12.C > new file mode 100644 > index 0000000..430d57d > --- /dev/null > +++ b/gcc/testsuite/g++.dg/abi/empty12.C > @@ -0,0 +1,17 @@ > +// PR c++/60336 > +// { dg-do run } > +// { dg-options "-x c" } > +// { dg-additional-sources "empty12a.c" } > +// { dg-prune-output "command line option" } > + > +#include "empty12.h" > +extern "C" void fun(struct dummy, struct foo); > + > +int main() > +{ > + struct dummy d; > + struct foo f = { -1, -2, -3, -4, -5 }; > + > + fun(d, f); > + return 0; > +} > diff --git a/gcc/testsuite/g++.dg/abi/empty12.h b/gcc/testsuite/g++.dg/abi/empty12.h > new file mode 100644 > index 0000000..c61afcd > --- /dev/null > +++ b/gcc/testsuite/g++.dg/abi/empty12.h > @@ -0,0 +1,9 @@ > +struct dummy { }; > +struct foo > +{ > + int i1; > + int i2; > + int i3; > + int i4; > + int i5; > +}; > diff --git a/gcc/testsuite/g++.dg/abi/empty12a.c b/gcc/testsuite/g++.dg/abi/empty12a.c > new file mode 100644 > index 0000000..34a25ba > --- /dev/null > +++ b/gcc/testsuite/g++.dg/abi/empty12a.c > @@ -0,0 +1,6 @@ > +#include "empty12.h" > +void fun(struct dummy d, struct foo f) > +{ > + if (f.i1 != -1) > + __builtin_abort(); > +} > diff --git a/gcc/testsuite/g++.dg/pr60336-1.C b/gcc/testsuite/g++.dg/pr60336-1.C > new file mode 100644 > index 0000000..af08638 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/pr60336-1.C > @@ -0,0 +1,17 @@ > +// { dg-do compile } > +// { dg-options "-O2 -std=c++11 -fno-pic" } > +// { dg-require-effective-target fpic } > + > +struct dummy { }; > +struct true_type { struct dummy i; }; > + > +extern true_type y; > +extern void xxx (true_type c); > + > +void > +yyy (void) > +{ > + xxx (y); > +} > + > +// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } } > diff --git a/gcc/testsuite/g++.dg/pr60336-2.C b/gcc/testsuite/g++.dg/pr60336-2.C > new file mode 100644 > index 0000000..7b902e8 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/pr60336-2.C > @@ -0,0 +1,28 @@ > +// { dg-do run } > +// { dg-options "-O2" } > + > +#include <stdarg.h> > + > +struct dummy { struct{}__attribute__((aligned (4))) a[7]; }; > + > +void > +test (struct dummy a, ...) > +{ > + va_list va_arglist; > + int i; > + > + va_start (va_arglist, a); > + i = va_arg (va_arglist, int); > + if (i != 0x10) > + __builtin_abort (); > + va_end (va_arglist); > +} > + > +struct dummy a0; > + > +int > +main () > +{ > + test (a0, 0x10); > + return 0; > +} > diff --git a/gcc/testsuite/g++.dg/pr68355.C b/gcc/testsuite/g++.dg/pr68355.C > new file mode 100644 > index 0000000..1354fc4 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/pr68355.C > @@ -0,0 +1,24 @@ > +// { dg-do compile } > +// { dg-options "-O2 -std=c++11 -fno-pic" } > +// { dg-require-effective-target fpic } > + > +template<typename _Tp, _Tp __v> > +struct integral_constant > +{ > + static constexpr _Tp value = __v; > + typedef _Tp value_type; > + typedef integral_constant<_Tp, __v> type; > + constexpr operator value_type() const { return value; } > +}; > + > +typedef integral_constant<bool, true> true_type; > +extern void xxx (true_type c); > + > +void > +yyy (void) > +{ > + true_type y; > + xxx (y); > +} > + > +// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx17integral_constantIbLb1EE" { target i?86-*-* x86_64-*-* } } } > diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c > index bb5cd49..6b1e25d 100644 > --- a/gcc/tree-dfa.c > +++ b/gcc/tree-dfa.c > @@ -394,6 +394,8 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, > machine_mode mode = TYPE_MODE (TREE_TYPE (exp)); > if (mode == BLKmode) > size_tree = TYPE_SIZE (TREE_TYPE (exp)); > + else if (lang_hooks.decls.empty_record_p (TREE_TYPE (exp))) > + bitsize = 0; > else > bitsize = int (GET_MODE_PRECISION (mode)); > } > diff --git a/gcc/tree-streamer-in.c b/gcc/tree-streamer-in.c > index 65a1ce3..1c32d81 100644 > --- a/gcc/tree-streamer-in.c > +++ b/gcc/tree-streamer-in.c > @@ -154,6 +154,11 @@ unpack_ts_base_value_fields (struct bitpack_d *bp, tree expr) > } > else > bp_unpack_value (bp, 9); > + if (TYPE_P (expr)) > + /* Set if a record is empty. */ > + TYPE_LANG_FLAG_0 (expr) = (unsigned) bp_unpack_value (bp, 1); > + else > + bp_unpack_value (bp, 1); > } > > > diff --git a/gcc/tree-streamer-out.c b/gcc/tree-streamer-out.c > index d0b7f6d..a1bf962 100644 > --- a/gcc/tree-streamer-out.c > +++ b/gcc/tree-streamer-out.c > @@ -31,6 +31,7 @@ along with GCC; see the file COPYING3. If not see > #include "alias.h" > #include "stor-layout.h" > #include "gomp-constants.h" > +#include "langhooks.h" > > > /* Output the STRING constant to the string > @@ -128,6 +129,11 @@ pack_ts_base_value_fields (struct bitpack_d *bp, tree expr) > } > else > bp_pack_value (bp, 0, 9); > + if (TYPE_P (expr)) > + /* Stream out a bit to indicate if a record is empty. */ > + bp_pack_value (bp, lang_hooks.decls.empty_record_p (expr), 1); > + else > + bp_pack_value (bp, 0, 1); > } > > > -- > 2.4.3 >
On Tue, Nov 17, 2015 at 4:22 AM, Richard Biener <richard.guenther@gmail.com> wrote: > On Tue, Nov 17, 2015 at 12:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote: >> Empty record should be returned and passed the same way in C and C++. >> This patch adds LANG_HOOKS_EMPTY_RECORD_P for C++ empty class, which >> defaults to return false. For C++, LANG_HOOKS_EMPTY_RECORD_P is defined >> to is_really_empty_class, which returns true for C++ empty classes. For >> LTO, we stream out a bit to indicate if a record is empty and we store >> it in TYPE_LANG_FLAG_0 when streaming in. get_ref_base_and_extent is >> changed to set bitsize to 0 for empty records. Middle-end and x86 >> backend are updated to ignore empty records for parameter passing and >> function value return. Other targets may need similar changes. > > Please avoid a new langhook for this and instead claim a bit in tree_type_common > like for example restrict_flag (double-check it is unused for non-pointers). There is no bit in tree_type_common I can overload. restrict_flag is checked for non-pointers to issue an error when it is used on non-pointers: /export/gnu/import/git/sources/gcc/gcc/testsuite/g++.dg/template/qualttp20.C:19:38: error: ‘__restrict__’ qualifiers cannot be applied to ‘AS::L’ typedef typename T::L __restrict__ r;// { dg-error "'__restrict__' qualifiers cannot" "" } Should I add a bit to tree_type_common? It may crease the size of tree_type_common by 4 bytes since there is unused bits in tree_type_common. > I don't like that you need to modify targets - those checks should be done > in the caller (which may just use a new wrapper with the logic and then > dispatching to the actual hook). I can do that. > Why do you need do adjust get_ref_base_and_extent? get_ref_base_and_extent is changed to set bitsize to 0 for empty records so that when ref_maybe_used_by_call_p_1 calls get_ref_base_and_extent to get 0 as the maximum size on empty record. Otherwise, find_tail_calls won't perform tail call optimization for functions with empty record parameters, as in struct dummy { }; struct true_type { struct dummy i; }; extern true_type y; extern void xxx (true_type c); void yyy (void) { xxx (y); }
On 11/20/2015 01:52 PM, H.J. Lu wrote: > On Tue, Nov 17, 2015 at 4:22 AM, Richard Biener > <richard.guenther@gmail.com> wrote: >> On Tue, Nov 17, 2015 at 12:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote: >>> Empty record should be returned and passed the same way in C and C++. >>> This patch adds LANG_HOOKS_EMPTY_RECORD_P for C++ empty class, which >>> defaults to return false. For C++, LANG_HOOKS_EMPTY_RECORD_P is defined >>> to is_really_empty_class, which returns true for C++ empty classes. For >>> LTO, we stream out a bit to indicate if a record is empty and we store >>> it in TYPE_LANG_FLAG_0 when streaming in. get_ref_base_and_extent is >>> changed to set bitsize to 0 for empty records. Middle-end and x86 >>> backend are updated to ignore empty records for parameter passing and >>> function value return. Other targets may need similar changes. >> >> Please avoid a new langhook for this and instead claim a bit in tree_type_common >> like for example restrict_flag (double-check it is unused for non-pointers). > > There is no bit in tree_type_common I can overload. restrict_flag is > checked for non-pointers to issue an error when it is used on non-pointers: > > /export/gnu/import/git/sources/gcc/gcc/testsuite/g++.dg/template/qualttp20.C:19:38: > error: ‘__restrict__’ qualifiers cannot be applied to ‘AS::L’ > typedef typename T::L __restrict__ r;// { dg-error "'__restrict__' > qualifiers cannot" "" } The C++ front end only needs to check TYPE_RESTRICT for this purpose on front-end-specific type codes like TEMPLATE_TYPE_PARM; cp_type_quals could handle that specifically if you change TYPE_RESTRICT to only apply to pointers. Jason
On Fri, Nov 20, 2015 at 2:17 PM, Jason Merrill <jason@redhat.com> wrote: > On 11/20/2015 01:52 PM, H.J. Lu wrote: >> >> On Tue, Nov 17, 2015 at 4:22 AM, Richard Biener >> <richard.guenther@gmail.com> wrote: >>> >>> On Tue, Nov 17, 2015 at 12:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote: >>>> >>>> Empty record should be returned and passed the same way in C and C++. >>>> This patch adds LANG_HOOKS_EMPTY_RECORD_P for C++ empty class, which >>>> defaults to return false. For C++, LANG_HOOKS_EMPTY_RECORD_P is defined >>>> to is_really_empty_class, which returns true for C++ empty classes. For >>>> LTO, we stream out a bit to indicate if a record is empty and we store >>>> it in TYPE_LANG_FLAG_0 when streaming in. get_ref_base_and_extent is >>>> changed to set bitsize to 0 for empty records. Middle-end and x86 >>>> backend are updated to ignore empty records for parameter passing and >>>> function value return. Other targets may need similar changes. >>> >>> >>> Please avoid a new langhook for this and instead claim a bit in >>> tree_type_common >>> like for example restrict_flag (double-check it is unused for >>> non-pointers). >> >> >> There is no bit in tree_type_common I can overload. restrict_flag is >> checked for non-pointers to issue an error when it is used on >> non-pointers: >> >> >> /export/gnu/import/git/sources/gcc/gcc/testsuite/g++.dg/template/qualttp20.C:19:38: >> error: ‘__restrict__’ qualifiers cannot be applied to ‘AS::L’ >> typedef typename T::L __restrict__ r;// { dg-error "'__restrict__' >> qualifiers cannot" "" } > > > The C++ front end only needs to check TYPE_RESTRICT for this purpose on > front-end-specific type codes like TEMPLATE_TYPE_PARM; cp_type_quals could > handle that specifically if you change TYPE_RESTRICT to only apply to > pointers. > restrict_flag is also checked in this case: [hjl@gnu-6 gcc]$ cat x.i struct dummy { }; struct dummy foo (struct dummy __restrict__ i) { return i; } [hjl@gnu-6 gcc]$ gcc -S x.i -Wall x.i:4:13: error: invalid use of ‘restrict’ foo (struct dummy __restrict__ i) ^ x.i:4:13: error: invalid use of ‘restrict’ [hjl@gnu-6 gcc]$ restrict_flag can't also be used to indicate `i' is an empty record. H.J.
On Sat, Nov 21, 2015 at 12:46 AM, H.J. Lu <hjl.tools@gmail.com> wrote: > On Fri, Nov 20, 2015 at 2:17 PM, Jason Merrill <jason@redhat.com> wrote: >> On 11/20/2015 01:52 PM, H.J. Lu wrote: >>> >>> On Tue, Nov 17, 2015 at 4:22 AM, Richard Biener >>> <richard.guenther@gmail.com> wrote: >>>> >>>> On Tue, Nov 17, 2015 at 12:01 PM, H.J. Lu <hjl.tools@gmail.com> wrote: >>>>> >>>>> Empty record should be returned and passed the same way in C and C++. >>>>> This patch adds LANG_HOOKS_EMPTY_RECORD_P for C++ empty class, which >>>>> defaults to return false. For C++, LANG_HOOKS_EMPTY_RECORD_P is defined >>>>> to is_really_empty_class, which returns true for C++ empty classes. For >>>>> LTO, we stream out a bit to indicate if a record is empty and we store >>>>> it in TYPE_LANG_FLAG_0 when streaming in. get_ref_base_and_extent is >>>>> changed to set bitsize to 0 for empty records. Middle-end and x86 >>>>> backend are updated to ignore empty records for parameter passing and >>>>> function value return. Other targets may need similar changes. >>>> >>>> >>>> Please avoid a new langhook for this and instead claim a bit in >>>> tree_type_common >>>> like for example restrict_flag (double-check it is unused for >>>> non-pointers). >>> >>> >>> There is no bit in tree_type_common I can overload. restrict_flag is >>> checked for non-pointers to issue an error when it is used on >>> non-pointers: >>> >>> >>> /export/gnu/import/git/sources/gcc/gcc/testsuite/g++.dg/template/qualttp20.C:19:38: >>> error: ‘__restrict__’ qualifiers cannot be applied to ‘AS::L’ >>> typedef typename T::L __restrict__ r;// { dg-error "'__restrict__' >>> qualifiers cannot" "" } >> >> >> The C++ front end only needs to check TYPE_RESTRICT for this purpose on >> front-end-specific type codes like TEMPLATE_TYPE_PARM; cp_type_quals could >> handle that specifically if you change TYPE_RESTRICT to only apply to >> pointers. >> > > restrict_flag is also checked in this case: > > [hjl@gnu-6 gcc]$ cat x.i > struct dummy { }; > > struct dummy > foo (struct dummy __restrict__ i) > { > return i; > } > [hjl@gnu-6 gcc]$ gcc -S x.i -Wall > x.i:4:13: error: invalid use of ‘restrict’ > foo (struct dummy __restrict__ i) > ^ > x.i:4:13: error: invalid use of ‘restrict’ > [hjl@gnu-6 gcc]$ > > restrict_flag can't also be used to indicate `i' is an empty record. I'm sure this error can be done during parsing w/o relying on TYPE_RESTRICT. But well, use any other free bit (but do not enlarge tree_type_common). Eventually you can free up a bit by putting sth into type_lang_specific currently using bits in tree_type_common. Richard. > > H.J.
diff --git a/gcc/calls.c b/gcc/calls.c index b56556a..ecc9b7a 100644 --- a/gcc/calls.c +++ b/gcc/calls.c @@ -4835,7 +4835,10 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, Note that in C the default argument promotions will prevent such mismatches. */ - size = GET_MODE_SIZE (arg->mode); + if (lang_hooks.decls.empty_record_p (TREE_TYPE (pval))) + size = 0; + else + size = GET_MODE_SIZE (arg->mode); /* Compute how much space the push instruction will push. On many machines, pushing a byte will advance the stack pointer by a halfword. */ @@ -4865,10 +4868,14 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, /* This isn't already where we want it on the stack, so put it there. This can either be done with push or copy insns. */ - if (!emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), NULL_RTX, - parm_align, partial, reg, used - size, argblock, - ARGS_SIZE_RTX (arg->locate.offset), reg_parm_stack_space, - ARGS_SIZE_RTX (arg->locate.alignment_pad), true)) + if (used + && !emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), + NULL_RTX, parm_align, partial, reg, + used - size, argblock, + ARGS_SIZE_RTX (arg->locate.offset), + reg_parm_stack_space, + ARGS_SIZE_RTX (arg->locate.alignment_pad), + true)) sibcall_failure = 1; /* Unless this is a partially-in-register argument, the argument is now @@ -4900,10 +4907,16 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, { /* PUSH_ROUNDING has no effect on us, because emit_push_insn for BLKmode is careful to avoid it. */ + bool empty_record + = lang_hooks.decls.empty_record_p (TREE_TYPE (pval)); excess = (arg->locate.size.constant - - int_size_in_bytes (TREE_TYPE (pval)) + - (empty_record + ? 0 + : int_size_in_bytes (TREE_TYPE (pval))) + partial); - size_rtx = expand_expr (size_in_bytes (TREE_TYPE (pval)), + size_rtx = expand_expr ((empty_record + ? size_zero_node + : size_in_bytes (TREE_TYPE (pval))), NULL_RTX, TYPE_MODE (sizetype), EXPAND_NORMAL); } @@ -4971,10 +4984,13 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, } } - emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), size_rtx, - parm_align, partial, reg, excess, argblock, - ARGS_SIZE_RTX (arg->locate.offset), reg_parm_stack_space, - ARGS_SIZE_RTX (arg->locate.alignment_pad), false); + if (!CONST_INT_P (size_rtx) || INTVAL (size_rtx) != 0) + emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), + size_rtx, parm_align, partial, reg, excess, + argblock, ARGS_SIZE_RTX (arg->locate.offset), + reg_parm_stack_space, + ARGS_SIZE_RTX (arg->locate.alignment_pad), + false); /* Unless this is a partially-in-register argument, the argument is now in the stack. @@ -5052,6 +5068,9 @@ must_pass_in_stack_var_size_or_pad (machine_mode mode, const_tree type) if (TREE_ADDRESSABLE (type)) return true; + if (lang_hooks.decls.empty_record_p (type)) + return false; + /* If the padding and mode of the type is such that a copy into a register would put it into the wrong part of the register. */ if (mode == BLKmode diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 6173dae..8bd6198 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -7920,6 +7920,9 @@ static int classify_argument (machine_mode mode, const_tree type, enum x86_64_reg_class classes[MAX_CLASSES], int bit_offset) { + if (type && lang_hooks.decls.empty_record_p (type)) + return 0; + HOST_WIDE_INT bytes = (mode == BLKmode) ? int_size_in_bytes (type) : (int) GET_MODE_SIZE (mode); int words = CEIL (bytes + (bit_offset % 64) / 8, UNITS_PER_WORD); @@ -8371,6 +8374,9 @@ construct_container (machine_mode mode, machine_mode orig_mode, static bool issued_sse_ret_error; static bool issued_x87_ret_error; + if (type && lang_hooks.decls.empty_record_p (type)) + return NULL; + machine_mode tmpmode; int bytes = (mode == BLKmode) ? int_size_in_bytes (type) : (int) GET_MODE_SIZE (mode); @@ -8783,6 +8789,9 @@ ix86_function_arg_advance (cumulative_args_t cum_v, machine_mode mode, HOST_WIDE_INT bytes, words; int nregs; + if (type && lang_hooks.decls.empty_record_p (type)) + return; + if (mode == BLKmode) bytes = int_size_in_bytes (type); else @@ -9099,6 +9108,9 @@ ix86_function_arg (cumulative_args_t cum_v, machine_mode omode, HOST_WIDE_INT bytes, words; rtx arg; + if (type && lang_hooks.decls.empty_record_p (type)) + return NULL; + /* All pointer bounds arguments are handled separately here. */ if ((type && POINTER_BOUNDS_TYPE_P (type)) || POINTER_BOUNDS_MODE_P (mode)) @@ -9708,6 +9720,9 @@ ix86_return_in_memory (const_tree type, const_tree fntype ATTRIBUTE_UNUSED) if (POINTER_BOUNDS_TYPE_P (type)) return false; + if (type && lang_hooks.decls.empty_record_p (type)) + return false; + if (TARGET_64BIT) { if (ix86_function_type_abi (fntype) == MS_ABI) @@ -10266,7 +10281,8 @@ ix86_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p, indirect_p = pass_by_reference (NULL, TYPE_MODE (type), type, false); if (indirect_p) type = build_pointer_type (type); - size = int_size_in_bytes (type); + bool empty_record = type && lang_hooks.decls.empty_record_p (type); + size = empty_record ? 0 : int_size_in_bytes (type); rsize = CEIL (size, UNITS_PER_WORD); nat_mode = type_natural_mode (type, NULL, false); diff --git a/gcc/cp/class.c b/gcc/cp/class.c index 216a301..c380734 100644 --- a/gcc/cp/class.c +++ b/gcc/cp/class.c @@ -8068,8 +8068,8 @@ build_self_reference (void) /* Returns 1 if TYPE contains only padding bytes. */ -int -is_empty_class (tree type) +bool +is_empty_class (const_tree type) { if (type == error_mark_node) return 0; @@ -8084,7 +8084,7 @@ is_empty_class (tree type) possible combinations of empty classes and possibly a vptr. */ bool -is_really_empty_class (tree type) +is_really_empty_class (const_tree type) { if (CLASS_TYPE_P (type)) { @@ -8098,10 +8098,13 @@ is_really_empty_class (tree type) if (COMPLETE_TYPE_P (type) && is_empty_class (type)) return true; - for (binfo = TYPE_BINFO (type), i = 0; - BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i) - if (!is_really_empty_class (BINFO_TYPE (base_binfo))) - return false; + /* TYPE_BINFO may be zeron when is_really_empty_class is called + from LANG_HOOKS_EMPTY_RECORD_P. */ + binfo = TYPE_BINFO (type); + if (binfo) + for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i) + if (!is_really_empty_class (BINFO_TYPE (base_binfo))) + return false; for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) if (TREE_CODE (field) == FIELD_DECL && !DECL_ARTIFICIAL (field) diff --git a/gcc/cp/cp-lang.c b/gcc/cp/cp-lang.c index 048108d..80174cb 100644 --- a/gcc/cp/cp-lang.c +++ b/gcc/cp/cp-lang.c @@ -78,6 +78,8 @@ static tree cxx_enum_underlying_base_type (const_tree); #define LANG_HOOKS_EH_RUNTIME_TYPE build_eh_type_type #undef LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE #define LANG_HOOKS_ENUM_UNDERLYING_BASE_TYPE cxx_enum_underlying_base_type +#undef LANG_HOOKS_EMPTY_RECORD_P +#define LANG_HOOKS_EMPTY_RECORD_P is_really_empty_class /* Each front end provides its own lang hook initializer. */ struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER; diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 84437b4..dc79979 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -5578,8 +5578,8 @@ extern tree finish_struct (tree, tree); extern void finish_struct_1 (tree); extern int resolves_to_fixed_type_p (tree, int *); extern void init_class_processing (void); -extern int is_empty_class (tree); -extern bool is_really_empty_class (tree); +extern bool is_empty_class (const_tree); +extern bool is_really_empty_class (const_tree); extern void pushclass (tree); extern void popclass (void); extern void push_nested_class (tree); diff --git a/gcc/function.c b/gcc/function.c index afc2c87..b59157d 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -4093,8 +4093,11 @@ locate_and_pad_parm (machine_mode passed_mode, tree type, int in_regs, part_size_in_regs = (reg_parm_stack_space == 0 ? partial : 0); - sizetree - = type ? size_in_bytes (type) : size_int (GET_MODE_SIZE (passed_mode)); + if (type) + sizetree = (lang_hooks.decls.empty_record_p (type) + ? size_zero_node : size_in_bytes (type)); + else + sizetree = size_int (GET_MODE_SIZE (passed_mode)); where_pad = FUNCTION_ARG_PADDING (passed_mode, type); boundary = targetm.calls.function_arg_boundary (passed_mode, type); round_boundary = targetm.calls.function_arg_round_boundary (passed_mode, diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h index 18ac84d..df4cbf8 100644 --- a/gcc/langhooks-def.h +++ b/gcc/langhooks-def.h @@ -163,6 +163,7 @@ extern tree lhd_make_node (enum tree_code); #define LANG_HOOKS_GENERIC_GENERIC_PARAMETER_DECL_P hook_bool_const_tree_false #define LANG_HOOKS_FUNCTION_PARM_EXPANDED_FROM_PACK_P \ hook_bool_tree_tree_false +#define LANG_HOOKS_EMPTY_RECORD_P hook_bool_const_tree_false #define LANG_HOOKS_GET_GENERIC_FUNCTION_DECL hook_tree_const_tree_null #define LANG_HOOKS_TYPE_PROMOTES_TO lhd_type_promotes_to #define LANG_HOOKS_REGISTER_BUILTIN_TYPE lhd_register_builtin_type @@ -228,6 +229,7 @@ extern tree lhd_make_node (enum tree_code); LANG_HOOKS_FUNCTION_DECL_DELETED_P, \ LANG_HOOKS_GENERIC_GENERIC_PARAMETER_DECL_P, \ LANG_HOOKS_FUNCTION_PARM_EXPANDED_FROM_PACK_P, \ + LANG_HOOKS_EMPTY_RECORD_P, \ LANG_HOOKS_GET_GENERIC_FUNCTION_DECL, \ LANG_HOOKS_WARN_UNUSED_GLOBAL_DECL, \ LANG_HOOKS_POST_COMPILATION_PARSING_CLEANUPS, \ diff --git a/gcc/langhooks.h b/gcc/langhooks.h index d8d01fa..450bdee 100644 --- a/gcc/langhooks.h +++ b/gcc/langhooks.h @@ -177,6 +177,9 @@ struct lang_hooks_for_decls function parameter pack. */ bool (*function_parm_expanded_from_pack_p) (tree, tree); + /* Determine if a type is an empty record. */ + bool (*empty_record_p) (const_tree type); + /* Returns the generic declaration of a generic function instantiations. */ tree (*get_generic_function_decl) (const_tree); diff --git a/gcc/lto-streamer.h b/gcc/lto-streamer.h index 5aae9e9..cc4cede 100644 --- a/gcc/lto-streamer.h +++ b/gcc/lto-streamer.h @@ -128,7 +128,7 @@ along with GCC; see the file COPYING3. If not see String are represented in the table as pairs, a length in ULEB128 form followed by the data for the string. */ -#define LTO_major_version 5 +#define LTO_major_version 6 #define LTO_minor_version 0 typedef unsigned char lto_decl_flags_t; diff --git a/gcc/lto/lto-lang.c b/gcc/lto/lto-lang.c index 53dd8f6..dc849a4 100644 --- a/gcc/lto/lto-lang.c +++ b/gcc/lto/lto-lang.c @@ -1306,6 +1306,16 @@ static void lto_init_ts (void) tree_contains_struct[NAMESPACE_DECL][TS_DECL_MINIMAL] = 1; } +/* Return true if TYPE contains no actual data, just various possible + combinations of empty records. */ + +static bool +lto_empty_record_p (const_tree type) +{ + /* Set if a record is empty. */ + return TYPE_LANG_FLAG_0 (type); +} + #undef LANG_HOOKS_NAME #define LANG_HOOKS_NAME "GNU GIMPLE" #undef LANG_HOOKS_OPTION_LANG_MASK @@ -1363,6 +1373,9 @@ static void lto_init_ts (void) #undef LANG_HOOKS_INIT_TS #define LANG_HOOKS_INIT_TS lto_init_ts +#undef LANG_HOOKS_EMPTY_RECORD_P +#define LANG_HOOKS_EMPTY_RECORD_P lto_empty_record_p + struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER; /* Language hooks that are not part of lang_hooks. */ diff --git a/gcc/targhooks.c b/gcc/targhooks.c index c34b4e9..5e74dd9 100644 --- a/gcc/targhooks.c +++ b/gcc/targhooks.c @@ -74,6 +74,7 @@ along with GCC; see the file COPYING3. If not see #include "intl.h" #include "opts.h" #include "gimplify.h" +#include "langhooks.h" bool @@ -1823,9 +1824,12 @@ std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p, /* Hoist the valist value into a temporary for the moment. */ valist_tmp = get_initialized_tmp_var (valist, pre_p, NULL); + bool empty_record = lang_hooks.decls.empty_record_p (type); + /* va_list pointer is aligned to PARM_BOUNDARY. If argument actually requires greater alignment, we must perform dynamic alignment. */ if (boundary > align + && !empty_record && !integer_zerop (TYPE_SIZE (type))) { t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp, @@ -1852,7 +1856,7 @@ std_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p, } /* Compute the rounded size of the type. */ - type_size = size_in_bytes (type); + type_size = empty_record ? size_zero_node : size_in_bytes (type); rounded_size = round_up (type_size, align); /* Reduce rounded_size so it's sharable with the postqueue. */ diff --git a/gcc/testsuite/g++.dg/abi/empty12.C b/gcc/testsuite/g++.dg/abi/empty12.C new file mode 100644 index 0000000..430d57d --- /dev/null +++ b/gcc/testsuite/g++.dg/abi/empty12.C @@ -0,0 +1,17 @@ +// PR c++/60336 +// { dg-do run } +// { dg-options "-x c" } +// { dg-additional-sources "empty12a.c" } +// { dg-prune-output "command line option" } + +#include "empty12.h" +extern "C" void fun(struct dummy, struct foo); + +int main() +{ + struct dummy d; + struct foo f = { -1, -2, -3, -4, -5 }; + + fun(d, f); + return 0; +} diff --git a/gcc/testsuite/g++.dg/abi/empty12.h b/gcc/testsuite/g++.dg/abi/empty12.h new file mode 100644 index 0000000..c61afcd --- /dev/null +++ b/gcc/testsuite/g++.dg/abi/empty12.h @@ -0,0 +1,9 @@ +struct dummy { }; +struct foo +{ + int i1; + int i2; + int i3; + int i4; + int i5; +}; diff --git a/gcc/testsuite/g++.dg/abi/empty12a.c b/gcc/testsuite/g++.dg/abi/empty12a.c new file mode 100644 index 0000000..34a25ba --- /dev/null +++ b/gcc/testsuite/g++.dg/abi/empty12a.c @@ -0,0 +1,6 @@ +#include "empty12.h" +void fun(struct dummy d, struct foo f) +{ + if (f.i1 != -1) + __builtin_abort(); +} diff --git a/gcc/testsuite/g++.dg/pr60336-1.C b/gcc/testsuite/g++.dg/pr60336-1.C new file mode 100644 index 0000000..af08638 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr60336-1.C @@ -0,0 +1,17 @@ +// { dg-do compile } +// { dg-options "-O2 -std=c++11 -fno-pic" } +// { dg-require-effective-target fpic } + +struct dummy { }; +struct true_type { struct dummy i; }; + +extern true_type y; +extern void xxx (true_type c); + +void +yyy (void) +{ + xxx (y); +} + +// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx9true_type" { target i?86-*-* x86_64-*-* } } } diff --git a/gcc/testsuite/g++.dg/pr60336-2.C b/gcc/testsuite/g++.dg/pr60336-2.C new file mode 100644 index 0000000..7b902e8 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr60336-2.C @@ -0,0 +1,28 @@ +// { dg-do run } +// { dg-options "-O2" } + +#include <stdarg.h> + +struct dummy { struct{}__attribute__((aligned (4))) a[7]; }; + +void +test (struct dummy a, ...) +{ + va_list va_arglist; + int i; + + va_start (va_arglist, a); + i = va_arg (va_arglist, int); + if (i != 0x10) + __builtin_abort (); + va_end (va_arglist); +} + +struct dummy a0; + +int +main () +{ + test (a0, 0x10); + return 0; +} diff --git a/gcc/testsuite/g++.dg/pr68355.C b/gcc/testsuite/g++.dg/pr68355.C new file mode 100644 index 0000000..1354fc4 --- /dev/null +++ b/gcc/testsuite/g++.dg/pr68355.C @@ -0,0 +1,24 @@ +// { dg-do compile } +// { dg-options "-O2 -std=c++11 -fno-pic" } +// { dg-require-effective-target fpic } + +template<typename _Tp, _Tp __v> +struct integral_constant +{ + static constexpr _Tp value = __v; + typedef _Tp value_type; + typedef integral_constant<_Tp, __v> type; + constexpr operator value_type() const { return value; } +}; + +typedef integral_constant<bool, true> true_type; +extern void xxx (true_type c); + +void +yyy (void) +{ + true_type y; + xxx (y); +} + +// { dg-final { scan-assembler "jmp\[\t \]+\[^\$\]*?_Z3xxx17integral_constantIbLb1EE" { target i?86-*-* x86_64-*-* } } } diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c index bb5cd49..6b1e25d 100644 --- a/gcc/tree-dfa.c +++ b/gcc/tree-dfa.c @@ -394,6 +394,8 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, machine_mode mode = TYPE_MODE (TREE_TYPE (exp)); if (mode == BLKmode) size_tree = TYPE_SIZE (TREE_TYPE (exp)); + else if (lang_hooks.decls.empty_record_p (TREE_TYPE (exp))) + bitsize = 0; else bitsize = int (GET_MODE_PRECISION (mode)); } diff --git a/gcc/tree-streamer-in.c b/gcc/tree-streamer-in.c index 65a1ce3..1c32d81 100644 --- a/gcc/tree-streamer-in.c +++ b/gcc/tree-streamer-in.c @@ -154,6 +154,11 @@ unpack_ts_base_value_fields (struct bitpack_d *bp, tree expr) } else bp_unpack_value (bp, 9); + if (TYPE_P (expr)) + /* Set if a record is empty. */ + TYPE_LANG_FLAG_0 (expr) = (unsigned) bp_unpack_value (bp, 1); + else + bp_unpack_value (bp, 1); } diff --git a/gcc/tree-streamer-out.c b/gcc/tree-streamer-out.c index d0b7f6d..a1bf962 100644 --- a/gcc/tree-streamer-out.c +++ b/gcc/tree-streamer-out.c @@ -31,6 +31,7 @@ along with GCC; see the file COPYING3. If not see #include "alias.h" #include "stor-layout.h" #include "gomp-constants.h" +#include "langhooks.h" /* Output the STRING constant to the string @@ -128,6 +129,11 @@ pack_ts_base_value_fields (struct bitpack_d *bp, tree expr) } else bp_pack_value (bp, 0, 9); + if (TYPE_P (expr)) + /* Stream out a bit to indicate if a record is empty. */ + bp_pack_value (bp, lang_hooks.decls.empty_record_p (expr), 1); + else + bp_pack_value (bp, 0, 1); }