The code that lowers field references can sometimes introduce a double
    pointer indirection in cases where it is not/safe appropriate. For
    example, in
    
            var p **struct { f int }
            p.f = 0
    
    the assignment LHS was being incorrectly lowered to (*(*p)).f.
    Detect this situation and issue an error.
    
    Fixes golang/go#21770
    
    Reviewed-on: https://go-review.googlesource.com/62330

From-SVN: r251918

    
    Patch by Rainer Orth.
    
    Reviewed-on: https://go-review.googlesource.com/60732

From-SVN: r251574

This patch adds another machine_mode wrapper for modes that are
known to be COMPLEX_MODE_P.  There aren't yet many places that make
use of it, but that might change in future.

2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* coretypes.h (complex_mode): New type.
	* gdbhooks.py (build_pretty_printer): Handle it.
	* machmode.h (complex_mode): New class.
	(complex_mode::includes_p): New function.
	(is_complex_int_mode): Likewise.
	(is_complex_float_mode): Likewise.
	* genmodes.c (get_mode_class): Handle complex mode classes.
	* function.c (expand_function_end): Use is_complex_int_mode.

gcc/go/
	* go-lang.c (go_langhook_type_for_mode): Use is_complex_float_mode.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r251527

Replace checks of "GET_MODE_CLASS (...) == MODE_INT" with
"is_int_mode (..., &var)", in cases where it becomes useful
to refer to the mode as a scalar_int_mode.

2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* machmode.h (is_int_mode): New fuction.
	* combine.c (find_split_point): Use it.
	(combine_simplify_rtx): Likewise.
	(simplify_if_then_else): Likewise.
	(simplify_set): Likewise.
	(simplify_shift_const_1): Likewise.
	(simplify_comparison): Likewise.
	* config/aarch64/aarch64.c (aarch64_rtx_costs): Likewise.
	* cse.c (notreg_cost): Likewise.
	(cse_insn): Likewise.
	* cselib.c (cselib_lookup_1): Likewise.
	* dojump.c (do_jump_1): Likewise.
	(do_compare_rtx_and_jump): Likewise.
	* dse.c (get_call_args): Likewise.
	* dwarf2out.c (rtl_for_decl_init): Likewise.
	(native_encode_initializer): Likewise.
	* expmed.c (emit_store_flag_1): Likewise.
	(emit_store_flag): Likewise.
	* expr.c (convert_modes): Likewise.
	(store_field): Likewise.
	(expand_expr_real_1): Likewise.
	* fold-const.c (fold_read_from_constant_string): Likewise.
	* gimple-ssa-sprintf.c (get_format_string): Likewise.
	* optabs-libfuncs.c (gen_int_libfunc): Likewise.
	* optabs.c (expand_binop): Likewise.
	(expand_unop): Likewise.
	(expand_abs_nojump): Likewise.
	(expand_one_cmpl_abs_nojump): Likewise.
	* simplify-rtx.c (mode_signbit_p): Likewise.
	(val_signbit_p): Likewise.
	(val_signbit_known_set_p): Likewise.
	(val_signbit_known_clear_p): Likewise.
	(simplify_relational_operation_1): Likewise.
	* tree.c (vector_type_mode): Likewise.

gcc/go/
	* go-lang.c (go_langhook_type_for_mode): Use is_int_mode.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r251472

This patch adds a scalar_float_mode class, which wraps a mode enum
that is known to satisfy SCALAR_FLOAT_MODE_P.  Things like "SFmode"
now give a scalar_float_mode object instead of a machine_mode.
This in turn needs a change to the real.h format_helper, so that
it can accept both machine_modes and scalar_float_modes.

2017-08-30  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* coretypes.h (scalar_float_mode): New type.
	* machmode.h (mode_traits::from_int): Use machine_mode if
	USE_ENUM_MODES is defined.
	(is_a): New function.
	(as_a): Likewise.
	(dyn_cast): Likewise.
	(scalar_float_mode): New class.
	(scalar_float_mode::includes_p): New function.
	(is_float_mode): Likewise.
	* gdbhooks.py (MachineModePrinter): New class.
	(build_pretty_printer): Use it for scalar_float_mode.
	* real.h (FLOAT_MODE_FORMAT): Use as_a <scalar_float_mode>.
	(format_helper::format_helper): Turn into a template.
	* genmodes.c (get_mode_class): New function.
	(emit_insn_modes_h): Give modes the class returned by get_mode_class,
	or machine_mode if none.
	* config/aarch64/aarch64.c (aarch64_simd_valid_immediate): Use
	as_a <scalar_float_mode>.
	* dwarf2out.c (mem_loc_descriptor): Likewise.
	(insert_float): Likewise.
	(add_const_value_attribute): Likewise.
	* simplify-rtx.c (simplify_immed_subreg): Likewise.
	* optabs.c (expand_absneg_bit): Take a scalar_float_mode.
	(expand_unop): Update accordingly.
	(expand_abs_nojump): Likewise.
	(expand_copysign_absneg): Take a scalar_float_mode.
	(expand_copysign_bit): Likewise.
	(expand_copysign): Update accordingly.

gcc/ada/
	* gcc-interface/utils.c (gnat_type_for_mode): Use is_a
	<scalar_float_mode> instead of SCALAR_FLOAT_MODE_P.

gcc/go/
	* go-lang.c (go_langhook_type_for_mode): Use is_float_mode.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r251458

    
    Reviewed-on: https://go-review.googlesource.com/59913

From-SVN: r251440

    
    Reviewed-on: https://go-review.googlesource.com/59912

From-SVN: r251439

    
    Reviewed-on: https://go-review.googlesource.com/59911

From-SVN: r251436

    
    Reviewed-on: https://go-review.googlesource.com/59910

From-SVN: r251435

    
    Reviewed-on: https://go-review.googlesource.com/57550

From-SVN: r251420

	PR go/81893
    runtime: only use PPC GNU/Linux register code on little endian
    
    Reportedly the current code builds on little endian but not big endian.
    
    Fixes https://gcc.gnu.org/PR81893.
    
    Reviewed-on: https://go-review.googlesource.com/57110

From-SVN: r251188

    
    Reviewed-on: https://go-review.googlesource.com/56910

From-SVN: r251182

    
    Using -funwind-tables is necessary to permit Go code to correctly
    throw a panic through C code.  This hasn't been necessary in the past
    as -funwind-tables is the default on x86.  However, it is not the
    default for PPC AIX.
    
    Reviewed-on: https://go-review.googlesource.com/56650

From-SVN: r251179

    
    Reviewed-on: https://go-review.googlesource.com/54170

From-SVN: r251133

    
    Fix dumpregs on i386, implement dumpregs for PPC Linux/AIX, get PC on AIX.
    
    Reviewed-on: https://go-review.googlesource.com/56170

From-SVN: r251127

    
    It's possible to construct an lshift expression using unsafe.Sizeof
    that is technically a compile-time constant but can't be evaluated
    without going through backend methods. In this case, insure that
    Type::make_non_abstract_type is called on the numeric operand of the
    shift (as opposed to leaving as abstract), to avoid an assert later on
    in the compiler flow.
    
    Fixes golang/go#21372.
    
    Reviewed-on: https://go-review.googlesource.com/54370

From-SVN: r251006

    
    Libgo's implementation of math.Ldexp declared the libc "ldexp" as
    taking an 'int' exponent argument, which is not quite right for 64-bit
    platforms (exp arg is always int32); this could yield incorrect
    results for exponent values outside the range of Minint32/Maxint32.
    Fix by upating the type for the libc version of ldexp, and adding
    guards to screen for out-of-range exponents.
    
    Fixes #21323.
    
    Reviewed-on: https://go-review.googlesource.com/54250

From-SVN: r250992

2017-08-07  Martin Liska  <mliska@suse.cz>

	* attribs.h (canonicalize_attr_name): New function.
	(cmp_attribs): Move from c-format.c and adjusted.
	(is_attribute_p): Moved from tree.h.
	* tree-inline.c: Add new includes.
	* tree.c (cmp_attrib_identifiers): Use cmp_attribs.
	(private_is_attribute_p): Remove.
	(private_lookup_attribute): Likewise.
	(private_lookup_attribute_by_prefix): Simplify.
	(remove_attribute): Use is_attribute_p.
	* tree.h: Remove removed declarations.
2017-08-07  Martin Liska  <mliska@suse.cz>

	* array-notation-common.c: Add new includes.
	* c-format.c( handle_format_attribute): Canonicalize a format
	function name.
	* c-lex.c (c_common_has_attribute): Canonicalize name of an
	attribute.
	* c-pretty-print.c: Add new include.
2017-08-07  Martin Liska  <mliska@suse.cz>

	* parser.c (cp_parser_gnu_attribute_list): Canonicalize name of an
	attribute.
	(cp_parser_std_attribute): Likewise.
	* tree.c: Add new include.
2017-08-07  Martin Liska  <mliska@suse.cz>

	* c-parser.c (c_parser_attributes): Canonicalize name of an
	attribute.
2017-08-07  Martin Liska  <mliska@suse.cz>

	* go-gcc.cc (Gcc_backend::function): Look up for no_split_stack
	and not __no_split_stack__.
2017-08-07  Martin Liska  <mliska@suse.cz>

	* g++.dg/cpp0x/pr65558.C: Update scanned pattern.
	* gcc.dg/parm-impl-decl-1.c: Likewise.
	* gcc.dg/parm-impl-decl-3.c: Likewise.
	* gcc.dg/Wattributes-5.c: New test.

From-SVN: r250911

    
    Patch from Uros Bizjak.
    
    Reviewed-on: https://go-review.googlesource.com/53350

From-SVN: r250873

	PR go/81617
    libgo: change mksigtab to recognize glibc 2.26 NSIG expression
    
    Fixes golang/go#21147
    Fixes GCC PR 81617
    
    Reviewed-on: https://go-review.googlesource.com/52611

From-SVN: r250858

    
    When finalizing the methods of a named struct type, we used to
    finalize all the field types first.  That can fail if the field types
    refer indirectly to the named type.  Change it to just finalize the
    embedded field types first, and the rest of the fields later.
    
    Fixes golang/go#21253
    
    Reviewed-on: https://go-review.googlesource.com/52570

From-SVN: r250832

    
    Tweak Interface_field_reference_expression::do_get_backend to apply an
    additional backend type conversion to the returned result.  This is
    needed due to the fact that the top level type of the expression is a
    function descriptor, however the value being manufactured is a pointer
    to <thunk-descriptor, value> struct.
    
    Reviewed-on: https://go-review.googlesource.com/51712

From-SVN: r250686

    
    We recently started walking through the hash table of pointer types to
    finalize them.  Unfortunately it is possible to create a new pointer
    type while finalizing an existing one (test case: test/fixedbugs/issue5291)
    and that breaks the iteration.  So, instead, keep a list of
    placeholder pointer types, and iterate through them while permitting
    the list to be extended as we go.
    
    Reviewed-on: https://go-review.googlesource.com/51771

From-SVN: r250683

    
    For calls that return multiple results we used to create a temporary
    of struct type to hold the results, and also create a separate
    temporary for each result.  Then the call expression would copy each
    result out of the struct to the temporary, and Call_result_expression
    would refer to the desired temporary.
    
    Simplify this to just use a single temporary of struct type, and
    change Call_result_expression to fetch a field of the struct.
    
    This may reduce some incorrect tree sharing in the backend code.
    
    Reviewed-on: https://go-review.googlesource.com/51770

From-SVN: r250682

	* go-backend.c (go_write_export_data): Use EXCLUDE section for
	AIX.

From-SVN: r250648

    
    Patch by Uros Bizjak.
    
    Reviewed-on: https://go-review.googlesource.com/51370

From-SVN: r250588

    
    Add a new helper routine Type::finish_pointer_types that walks through
    the pointer type cache and looks for placeholder types that may have
    been created at some point before conversion of named types, and
    invokes Type::finish_backend() on said placeholders.  This is needed
    to handle cases where the compiler manufactures a pointer type as part
    of lowering, then a placeholder is created for it due to a call to
    Type::backend_type_size(), but there is no explicit reference to the
    type in user code.
    
    Reviewed-on: https://go-review.googlesource.com/51131

From-SVN: r250548

    
    We unconditionally set _FILE_OFFSET_BITS to 64 in configure.ac, so we
    should unconditionally call the statfs64 and fstatfs64 functions.
    These functions should be available on all versions of GNU/Linux since 2.6.
    On 64-bit systems they are aliased to statfs/fstatfs, and on 32-bit
    systems they use the 64-bit data structures.
    
    Fixes golang/go#20922
    
    Reviewed-on: https://go-review.googlesource.com/50635

From-SVN: r250443

    
    If getSiginfo does not know how to determine the PC, it will call
    runtime_callers. That can happen in a thread that was started by
    non-Go code, in which case the TLS variable g will not be set, in
    which case runtime_lock will crash.
    
    Avoid the problem by using atomic operations for the lock. This is OK
    since creating a backtrace state is fast and never blocks.
    
    The test case is TestCgoExternalThreadSIGPROF in the runtime package
    on a system that getSiginfo doesn't handle specially.
    
    Updates golang/go#20931
    
    Reviewed-on: https://go-review.googlesource.com/50650

From-SVN: r250439

    
    Updates golang/go#20931
    
    Reviewed-on: https://go-review.googlesource.com/50631

From-SVN: r250436

    
    Allocate enough stack space so that the test will work on a system
    that does not support split stacks.
    
    This test is actually not very meaningful for gccgo at present, but it
    doesn't hurt to keep running it.
    
    Updates golang/go#20931
    
    Reviewed-on: https://go-review.googlesource.com/50630

From-SVN: r250433

    
    The current recipe in Type_guard_expression for creating a Bexpression
    performs a type conversion at the Type level, but doesn't invoke
    Backend::convert_expression to capture the conversion for the back
    end. Add code to create a BE type conversion operation.
    
    Reviewed-on: https://go-review.googlesource.com/50373

From-SVN: r250400

    
    In Func_expression::do_get_backend when creating the backend
    representation for a closure, create a backend type conversion to
    account for potential differences between the closure struct type
    (where the number of fields is dependent on the number of values
    referenced in the closure) and the generic function descriptor type
    (struct with single function pointer field).
    
    Reviewed-on: https://go-review.googlesource.com/49255

From-SVN: r250327

re PR go/81451 (missing futex check - libgo/runtime/thread-linux.c:12:0 futex.h:13:12: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘long’)

	PR go/81451
    runtime: inline runtime_osinit
    
    We had two identical copies of runtime_osinit. They set runtime_ncpu,
    a variable that is no longer used. Removing that leaves us with two lines.
    Inline those two lines in the two places the function was called.
    
    This fixes GCC PR 81451.
    
    Reviewed-on: https://go-review.googlesource.com/48862

From-SVN: r250326

    
    The code in Named_type::do_get_backend was not passing the correct
    flag value for circular function types to Backend::circular_pointer_type
    (it was always setting this flag to false). Pass a true value if the
    type being converted is a function type.
    
    Reviewed-on: https://go-review.googlesource.com/49330

From-SVN: r250325

	PR go/81324
    sysinfo.c: ignore ptrace_peeksiginfo_args from <linux/ptrace.h>
    
    With some versions of glibc and GNU/Linux ptrace_pseeksiginfo_args is
    defined in both <sys/ptrace.h> and <linux/ptrace.h>. We don't actually
    care about the struct, so use a #define to avoid a redefinition error.
    
    This fixes https://gcc.gnu.org/PR81324.
    
    Reviewed-on: https://go-review.googlesource.com/49290

From-SVN: r250324

    
    https://gcc.gnu.org/PR81449 reports a problem with the definition semt
    in runtime.inc on some systems. Since the C code in libgo/runtime
    doesn't need semt, just don't copy it into runtime.inc.
    
    Reviewed-on: https://go-review.googlesource.com/48593

From-SVN: r250217

    
    Don't assume that all (or only) 386/amd64 compilers support
    -fsplit-stack.
    
    Reviewed-on: https://go-review.googlesource.com/48592

From-SVN: r250216

	PR go/81393
    syscall: don't use GETREGS/SETREGS on s390
    
    They were removed in recent glibc.
    
    Patch by Andreas Krebbel for GCC PR 81393.
    
    Reviewed-on: https://go-review.googlesource.com/48231

From-SVN: r250174

    
    This test is not yet run, but it will be soon.
    
    Reviewed-on: https://go-review.googlesource.com/47038

From-SVN: r249795