Several recent changes to the gc version of cmd/go improve the
    gofrontend support. These changes are partially copies of existing
    gofrontend differences, and partially new code. This CL makes the
    gofrontend match the upstream code.
    
    The changes included here come from:
        https://golang.org/cl/111575
        https://golang.org/cl/111595
        https://golang.org/cl/111635
        https://golang.org/cl/111636
    
    For the record, the following recent gc changes are based on code
    already present in the gofrontend repo:
        https://golang.org/cl/110915
        https://golang.org/cl/111615
    
    For the record, a gc change, partially based on earlier gofrontend
    work, also with new gc code, was already copied to gofrontend repo in
    CL 111099:
        https://golang.org/cl/111097
    
    This moves the generated list of standard library packages from
    cmd/go/internal/load to go/build.
    
    Reviewed-on: https://go-review.googlesource.com/112475

gotools/:
	* Makefile.am (check-go-tool): Don't copy zstdpkglist.go.
	* Makefile.in: Rebuild.

From-SVN: r260097

    
    Reviewed-on: https://go-review.googlesource.com/111535

From-SVN: r259946

    
    Change code to work properly reading unaligned data on architectures
    that don't support unaliged reads. This fixes a regression (broke
    Solaris/sparc) introduced in https://golang.org/cl/90235.
    
    Reviewed-on: https://go-review.googlesource.com/111296

From-SVN: r259935

    
    Update mkalldocs.sh from the current master sources, replacing the old
    mkdoc.sh.
    
    Reviewed-on: https://go-review.googlesource.com/111096

From-SVN: r259920

    
    Since gofrontend does have the vet tool now, we can test it.
    
    Reviewed-on: https://go-review.googlesource.com/111095

From-SVN: r259919

    
    In https://golang.org/cl/111097 the gc version of cmd/go was updated
    to include some gofrontend-specific changes. The gofrontend code
    already has different versions of those changes; this CL makes the
    gofrontend match the upstream code.
    
    Reviewed-on: https://go-review.googlesource.com/111099

From-SVN: r259918

    
    Tweak the array type checking code to avoid crashing on array types
    whose length expressions are explicit non-integer types (for example,
    "float64(10)"). If such constructs are seen, issue an "invalid array
    bound" error.
    
    Fixes golang/go#13486.
    
    Reviewed-on: https://go-review.googlesource.com/91975

From-SVN: r259900

    
    These tests used to be disabled in the gofrontend since the go tool
    didn't support build IDs for the gofrontend. It does now, so enable
    the tests again.
    
    Reviewed-on: https://go-review.googlesource.com/111098

From-SVN: r259875

    
    This patch adds explicit references to various types and constants
    defined by the header files included by sysinfo.c (used to drive the
    generation of gen-sysinfo.go as part of the libgo build via the GCC
    "-fdump-go-spec" option).
    
    The intent is to enable clients to gather the same info generated by
    "-fdump-go-spec" by instead reading the generated DWARF from a
    sysinfo.o object file compiled with "-g". Some compilers (notably
    clang) try to omit DWARF records for a given type unless there is an
    explicit use of it in the translation unit; the additional references
    are to insure that everything we want to see in the DWARF shows up.
    
    Reviewed-on: https://go-review.googlesource.com/99063

From-SVN: r259868

    
    Reviewed-on: https://go-review.googlesource.com/90775

From-SVN: r259866

	PR go/85429
    cmd/go: support more Solaris assembler syntaxes
    
    Patch by Rainer Orth.
    
    Reviewed-on: https://go-review.googlesource.com/110563

From-SVN: r259797

	PR go/85429
    cmd/go: add Solaris assembler syntax for gccgo buildid file
    
    The Solaris assembler uses a different syntax for section directives.
    
    This is https://golang.org/cl/109140 ported over to gccgo.
    
    Reviewed-on: https://go-review.googlesource.com/109141

From-SVN: r259719

    
    Reviewed-on: https://go-review.googlesource.com/108457

From-SVN: r259531

    
    Bring in https://golang.org/cl/98616 from gc tip.
    
    Original CL description:
    
        This change modifies Go to disable loading of users' shell history for
        TestTerminalSignal tests. TestTerminalSignal, as part of its workload,
        will execute a new interactive bash shell. Bash will attempt to load the
        user's history from the file pointed to by the HISTFILE environment
        variable. For users with large histories that may take up to several
        seconds, pushing the whole test past the 5 second timeout and causing
        it to fail.
    
    Reviewed-on: https://go-review.googlesource.com/107624

From-SVN: r259452

    
    Reviewed-on: https://go-review.googlesource.com/100955

From-SVN: r259445

    
    The gccgo runtime is never stale, and on a system with gc sources in
    ~/go the test may wind up checking whether the gc runtime is stale.
    
    Reviewed-on: https://go-review.googlesource.com/102282

From-SVN: r258865

    
    Also add noinst_DATA to CHECK_DEPS; it's not needed in practice since
    `make` will build noinst_DATA, but it's logically required and will
    make a difference if any of the noinst_DATA sources change between
    `make` and `make check`.
    
    Tony Reix figured out why omitting packages from noinst_DATA didn't
    seem to matter: because if gccgo can't find foo.gox, it will fall back
    to reading the export data in foo.o, and foo.o will exist because
    these packages go into libgo.a.
    
    Reviewed-on: https://go-review.googlesource.com/101077

From-SVN: r258606

    
    Tested by installing the gcc-locales package and running
        LANG=de_DE.utf8 go build hello.go
    Without this change, that fails, as described at
    https://gcc.gnu.org/PR84765.
    
    Reviewed-on: https://go-review.googlesource.com/100737

From-SVN: r258565

    Makefile: add internal/trace to noinst_DATA
    
    The internal/trace package is only imported by tests (specifically the
    tests in runtime/trace) so it must be in noinst_DATA to ensure that it
    is built before running the tests.
    
    This was mostly working because internal/trace has tests itself, and
    is listed in check-packages.txt before runtime/trace, so typical
    invocations of make would build internal/trace for checking purposes
    before checking runtime/trace.  But we need this change to make that
    reliable.
    
    Reviewed-on: https://go-review.googlesource.com/99836

From-SVN: r258392

    
    Reviewed-on: https://go-review.googlesource.com/99117

From-SVN: r258337

    
    This implements the same choices made in the gc runtime, except that
    for 32-bit x86 we only use the fence instruction if the processor
    supports SSE2.
    
    The code here is hacked up for speed; the gc runtime uses straight
    assembler.
    
    Reviewed-on: https://go-review.googlesource.com/97715

From-SVN: r258336

    
    Fix a small typo in the mksysinfo.sh script (incorrect input
    file for a grep command).
    
    Reviewed-on: https://go-review.googlesource.com/98635

From-SVN: r258259

    
    The compiler was crashing partway through emitting an error for a bad
    self-referential struct type (which refers to one of its own fields
    via an unsafe.Offset expression). Tweak the offset logic to check for
    this class of type error and exit cleanly.
    
    Fixes golang/go#24180
    
    Reviewed-on: https://go-review.googlesource.com/97855

From-SVN: r258112

    
    Reviewed-on: https://go-review.googlesource.com/97357

From-SVN: r258052

    
    Reviewed-on: https://go-review.googlesource.com/97517

From-SVN: r258051

    
    We want to track references to fields in the real struct, not in
    aliases to the struct.
    
    Reviewed-on: https://go-review.googlesource.com/96816

From-SVN: r257954

    
    Copy the idea of https://golang.org/cl/92756 to funcfileline, which is
    used by runtime.FuncForPC, runtime.(*Frames).Next, and others.
    
    Reviewed-on: https://go-review.googlesource.com/96175

From-SVN: r257913

    
    Fixes https://gcc.gnu.org/PR84484
    
    Reviewed-on: https://go-review.googlesource.com/95436

From-SVN: r257911

    
    Let a fast syscall return be a preemption point.  This helps with
    tight loops that make system calls, as in BenchmarkSyscallExcessWork.
    
    Reviewed-on: https://go-review.googlesource.com/94895

From-SVN: r257848

    
    Aliases are supposed to be identical to the type being aliased, so
    questions about type compatibility need to always ignore aliases,
    except for error messages involving the type name.
    
    The test case for this is https://golang.org/cl/94995.
    
    Fixes golang/go#23912
    
    Reviewed-on: https://go-review.googlesource.com/94996

From-SVN: r257845

    
    In particular this lets BenchmarkPingPongHog in runtime/proc_test.go
    complete.
    
    Reviewed-on: https://go-review.googlesource.com/94735

From-SVN: r257743

    
    They aren't needed, and could potentially cause unlikely symbol name
    collisions.  Also, the runtime package's reference to main could cause
    the runtime package to define main.main..f, which could also be
    defined in the main package if it does something like fmt.Print(main).
    That will normally work but will fail with a multiple symbol
    definition error when using -static-libgo.
    
    Reviewed-on: https://go-review.googlesource.com/93656

From-SVN: r257637

    
    Long long long ago Go permitted writing
        func F()
    in one file and writing
        func F() {}
    in another file.  This was removed from the language, and that is now
    considered to be a multiple definition error.  Gccgo never caught up
    to that, and it has been permitting this invalid code for some time.
    
    Stop permitting it, so that we give correct errors.  Since we've
    supported it for a long time, the compiler uses it in a couple of
    cases: it predeclares the hash/equal methods if it decides to create
    them while compiling another function, and it predeclares main.main as
    a mechanism for getting the right warning if a program uses the wrong
    signature for main.  For simplicity, keep those existing uses.
    
    This required a few minor changes in libgo which were relying,
    unnecessarily, on the current behavior.
    
    Reviewed-on: https://go-review.googlesource.com/93083

From-SVN: r257600

	PR go/84215
    runtime, sync/atomic: use write barrier for atomic pointer functions
    
    This copies atomic_pointer.go from 1.10rc2.  It was omitted during the
    transition of the runtime from C to Go, and I forgot about it.
    
    This may help with https://gcc.gnu.org/PR84215.
    
    Reviewed-on: https://go-review.googlesource.com/93197

From-SVN: r257599

    
    The magic //go:nointerface comment, used for field tracking, was only
    implemented for conversions to interface types in the same package.
    Record it in the export data, so that it works as expected for types
    imported from a different package.
    
    Reviewed-on: https://go-review.googlesource.com/93075

From-SVN: r257540

    
    If we trace back through code that has no debug info, as when calling
    through C code compiled with -g0, we won't have a function name.
    Try to fetch the function name using the symbol table.
    
    Adding the test case revealed that gotest failed to use the gccgo tag
    when matching files, so add that.
    
    Reviewed-on: https://go-review.googlesource.com/92756

From-SVN: r257495

    
    Reviewed-on: https://go-review.googlesource.com/92736

From-SVN: r257493

    
    The escape analysis support is not yet good enough to avoid escaping
    the argument to funcPC.  This causes unnecessary and often harmful
    memory allocation.  E.g., (*cpuProfile).addExtra can be called from a
    signal handler, and it must not allocate memory.
    
    Move the calls to funcPC to use variables instead.  This was done in
    the original migration to using funcPC, but was not done for newer code.
    
    In one case, in signal handling code, use getSigtramp.
    
    Reviewed-on: https://go-review.googlesource.com/92735

From-SVN: r257463

    
    Normally we ensure to build a single Btype for identical types.
    We did not do this for methods table of identical interface
    types, however. If there are two identical interface type I, I2,
    they have the same Btype BI, but different Btypes for their
    methods tables, BM and BM2. From the backend's point of view
    only one of them is linked to BI. This can cause inconsitency
    in the backend's type system, like unresolved placeholder. This
    CL ensures we create a single Btype for methods table of
    identical interface type.
    
    Reviewed-on: https://go-review.googlesource.com/92436

From-SVN: r257436

    
    Check for negative numbers with very small magnitudes that will round
    to negative zero, and force them to positive zero instead.
    
    This implements the spec clarification in https://golang.org/cl/14727.
    The test is in https://golang.org/cl/91895.
    
    Fixes golang/go#12621
    
    Reviewed-on: https://go-review.googlesource.com/92175

From-SVN: r257415