This replaces runtime/cpuprof.goc with go/runtime/cpuprof.go and adjusts
the supporting code in runtime/proc.c.
This adds another case where the compiler needs to avoid heap allocation
in the runtime package: when evaluating a method expression into a
closure. Implementing this required moving the relevant code from
do_get_backend to do_flatten, so that I could easily add a temporary
variable. Doing that let me get rid of Bound_method_expression::do_lower.
Reviewed-on: https://go-review.googlesource.com/31050
From-SVN: r241163
This replaces mem.go and the C runtime_ReadMemStats function with the Go
1.7 mstats.go.
The GCStats code is commented out for now. The corresponding gccgo code
is in runtime/mgc0.c.
The variables memstats and worldsema are shared between the Go code and
the C code, but are not exported. To make this work, add temporary
accessor functions acquireWorldsema, releaseWorldsema, getMstats (the
latter known as mstats in the C code).
Check the preemptoff field of m when allocating and when considering
whether to start a GC. This works with the new stopTheWorld and
startTheWorld functions in Go, which are essentially the Go 1.7
versions.
Change the compiler to stack allocate closures when compiling the
runtime package. Within the runtime packages closures do not escape.
This is similar to what the gc compiler does, except that the gc
compiler, when compiling the runtime package, gives an error if escape
analysis shows that a closure does escape. I added this here because
the Go version of ReadMemStats calls systemstack with a closure, and
having that allocate memory was causing some tests that measure memory
allocations to fail.
Reviewed-on: https://go-review.googlesource.com/30972
From-SVN: r241124
Add compiler support for turning concatenating strings into a call to
a runtime function that takes the appropriate number of arguments.
Rename some local variables in mgc0.c to avoid macros that the new
rune.go causes to appear in runtime.inc.
Reviewed-on: https://go-review.googlesource.com/30827
From-SVN: r241074
This triggered a check in releaseSudog that g.param not nil, because
libgo uses the param field when starting a goroutine. Fixed by clearing
g->param in kickoff in proc.c.
Reviewed-on: https://go-review.googlesource.com/30951
From-SVN: r241067
Since sparc is a valid architecture, the name of
getrandom_linux_sparc.go means that it will be ignored on sparc64,
even though it's whitelisted with a +build line.
On SPARC, clone has a unique return value convention which requires
some inline assembly to convert it to the normal convention.
Reviewed-on: https://go-review.googlesource.com/30873
From-SVN: r241051
Update the compiler to use the new names. Add calls to printlock and
printunlock around print statements. Move expression evaluation before
the call to printlock. Update g's writebuf field to a slice, and adjust
C code accordingly.
Reviewed-on: https://go-review.googlesource.com/30717
From-SVN: r240958
Update the compiler to use the new names. Add calls to printlock and
printunlock around print statements. Move expression evaluation before
the call to printlock. Update g's writebuf field to a slice, and adjust
C code accordingly.
Reviewed-on: https://go-review.googlesource.com/30717
From-SVN: r240956
Change the compiler to use the new routines. Drop the separation of
small and large values when sending on a channel. Allocate the select
struct on the stack. Remove the old C implementation of channels. Adjust
the garbage collector for the new data structure.
Bring in part of the tracing code, enough for the channel code to call.
Bump the permitted number of allocations in one of the tests in
context_test.go. The difference is that now receiving from a channel
allocates a sudog, which the C code used to simply put on the
stack. This will be somewhat better when we port proc.go.
Reviewed-on: https://go-review.googlesource.com/30714
From-SVN: r240941
Remove the old locking code written in C.
Add a shell script mkrsysinfo.sh to generate the runtime_sysinfo.go
file, so that we can get Go copies of the system time structures and
other types.
Tweak the compiler so that when compiling the runtime package the
address operator does not cause local variables to escape. When the gc
compiler compiles the runtime, an escaping local variable is treated as
an error. We should implement that, instead of this change, when escape
analysis is turned on.
Tweak the compiler so that the generated C header does not include names
that start with an underscore followed by a non-upper-case letter,
except for the special cases of _defer and _panic. Otherwise we
translate C types to Go in runtime_sysinfo.go and then generate those Go
types back as C types in runtime.inc, which is useless and painful for
the C code.
Change entersyscall and friends to take a dummy argument, as the gc
versions do, to simplify calls from the shared code.
Reviewed-on: https://go-review.googlesource.com/30079
From-SVN: r240657
Also copy over cputicks.go, env_posix.go, vdso_none.go, stubs2.go, and a
part of os_linux.go. Remove the corresponding functions from the C code
in libgo/go/runtime. Add some transitional support functions to
stubs.go. This converts several minor functions from C to Go.
Reviewed-on: https://go-review.googlesource.com/29962
From-SVN: r240609
This change removes the gccgo-specific hashmap code and replaces it with
the hashmap code from the Go 1.7 runtime. The Go 1.7 hashmap code is
more efficient, does a better job on details like when to update a key,
and provides some support against denial-of-service attacks.
The compiler is changed to call the new hashmap functions instead of the
old ones.
The compiler now tracks which types are reflexive and which require
updating when used as a map key, and records the information in map type
descriptors.
Map_index_expression is simplified. The special case for a map index on
the right hand side of a tuple expression has been unnecessary for some
time, and is removed. The support for specially marking a map index as
an lvalue is removed, in favor of lowering an assignment to a map index
into a function call. The long-obsolete support for a map index of a
pointer to a map is removed.
The __go_new_map_big function (known to the compiler as
Runtime::MAKEMAPBIG) is no longer needed, as the new runtime.makemap
function takes an int64 hint argument.
The old map descriptor type and supporting expression is removed.
The compiler was still supporting the long-obsolete syntax `m[k] = 0,
false` to delete a value from a map. That is now removed, requiring a
change to one of the gccgo-specific tests.
The builtin len function applied to a map or channel p is now compiled
as `p == nil ? 0 : *(*int)(p)`. The __go_chan_len function (known to
the compiler as Runtime::CHAN_LEN) is removed.
Support for a shared zero value for maps to large value types is
introduced, along the lines of the gc compiler. The zero value is
handled as a common variable.
The hash function is changed to take a seed argument, changing the
runtime hash functions and the compiler-generated hash functions.
Unlike the gc compiler, both the hash and equal functions continue to
take the type length.
Types that can not be compared now store nil for the hash and equal
functions, rather than pointing to functions that throw. Interface hash
and comparison functions now check explicitly for nil. This matches the
gc compiler and permits a simple implementation for ismapkey.
The compiler is changed to permit marking struct and array types as
incomparable, meaning that they have no hash or equal function. We use
this for thunk types, removing the existing special code to avoid
generating hash/equal functions for them.
The C runtime code adds memclr, memequal, and memmove functions.
The hashmap code uses go:linkname comments to make the functions
visible, as otherwise the compiler would discard them.
The hashmap code comments out the unused reference to the address of the
first parameter in the race code, as otherwise the compiler thinks that
the parameter escapes and copies it onto the heap. This is probably not
needed when we enable escape analysis.
Several runtime map tests that ere previously skipped for gccgo are now
run.
The Go runtime picks up type kind information and stubs. The type kind
information causes the generated runtime header file to define some
constants, including `empty`, and the C code is adjusted accordingly.
A Go-callable version of runtime.throw, that takes a Go string, is
added to be called from the hashmap code.
Reviewed-on: https://go-review.googlesource.com/29447
* go.go-torture/execute/map-1.go: Replace old map deletion syntax
with call to builtin delete function.
From-SVN: r240334
Copy over the Go 1.7 runtime/internal/sys package, but instead of having
separate files for each GOARCH and GOOS value, set the values in
configure.ac and write them out in Makefile.am. Setting the values in
configure.ac should make it easier to add new processors.
Remove the automake GOARCH conditionals, which are no longer used.
Leave the GOOS conditionals for now, as they are used for the C runtime
package.
Reviewed-on: https://go-review.googlesource.com/29018
From-SVN: r240083
Copy over the Go 1.7 runtime/internal/atomic package, but implement the
functions in C using __atomic functions rather than using the
processor-specific assembler code.
Reviewed-on: https://go-review.googlesource.com/29010
From-SVN: r240070
Some systems, such as ia64 and PPC, require that a ucontext_t pointer
passed to getcontext and friends be aligned to a 16-byte boundary.
Currently the ucontext_t fields in the g structure are defined in Go,
and Go has no way to ensure a 16-byte alignment for a struct field.
The fields are currently represented by an array of unsafe.Pointer.
Enforce the alignment by making the array larger, and picking an offset
into the array that is 16-byte aligned.
Reviewed-on: https://go-review.googlesource.com/28910
From-SVN: r240044
Use the new -fgo-c-header option to build a header file for the Go
runtime code in libgo/go/runtime, and use the new header file in the C
runtime code in libgo/runtime. This will ensure that the Go code and C
code share the same data structures as we convert the runtime from C to
Go.
The new file libgo/go/runtime/runtime2.go is copied from the Go 1.7
release, and then edited to remove unnecessary data structures and
modify others for use with libgo.
The new file libgo/go/runtime/mcache.go is an initial version of the
same files in the Go 1.7 release, and will be replaced by the Go 1.7
file when we convert to the new memory allocator.
The new file libgo/go/runtime/type.go describes the gccgo version of the
reflection data structures, and replaces the Go 1.7 runtime file which
describes the gc version of those structures.
Using the new header file means changing a number of struct fields to
use Go naming conventions (that is, no underscores) and to rename
constants to have a leading underscore so that they are not exported
from the Go package. These names were updated in the C code.
The C code was also changed to drop the thread-local variable m, as was
done some time ago in the gc sources. Now the m field is always
accessed using g->m, where g is the single remaining thread-local
variable. This in turn required some adjustments to set g->m correctly
in all cases.
Also pass the new -fgo-compiling-runtime option when compiling the
runtime package, although that option doesn't do anything yet.
Reviewed-on: https://go-review.googlesource.com/28051
From-SVN: r239872
The go/build package does not know that gccgo's standard packages don't
have source, and will report an error saying that it can not find them.
Work around that in the cmd/go sources, since the go/build sources don't
currently have a list of standard packages.
This should get a real fix in the master sources, somehow.
Fixesgolang/go#16701.
Reviewed-on: https://go-review.googlesource.com/27052
From-SVN: r239486
These files are used to select s390x assembler support in the gc
toolchain. We don't currently have that support, as it is written in
the cmd/asm syntax rather than gas syntax. Mark the files to be ignored
for now, falling back to the default implementations.
Patch by Andreas Krebbel.
Reviewed-on: https://go-review.googlesource.com/26994
From-SVN: r239442
We want to build dir_regfile.go if not GNU/linux, and not solaris/386,
and not solaris/sparc. The latter two conditions were incorrect. To
write ! solaris/386 we have to write !solaris !386. I forgot De
Morgan's Law.
Reviewed-on: https://go-review.googlesource.com/26870
From-SVN: r239393
We already lowered the limit of recursive template invocations from
100,000 to 10,000, but the tests still fail occasionally on
x86_64-pc-linux-gnu when using GNU ld (so that split stacks are not
fully functional). Reduce the limit further, to 1000, enough so that
the test passes consistently.
Permitting 1000 recursive template invocations still seems capacious
enough for real world use.
Reviewed-on: https://go-review.googlesource.com/25590
From-SVN: r239261
Also change the configure script to set GOARCH correctly for ia64, and
add ia64 as a processor to match.sh and gotest.
Reviewed-on: https://go-review.googlesource.com/25549
From-SVN: r239225
Previously the libgo Makefile explicitly listed the set of files to
compile for each package. For packages that use build tags, this
required a lot of awkward automake conditionals in the Makefile.
This CL changes the build to look at the build tags in the files.
The new shell script libgo/match.sh does the matching. This required
adjusting a lot of build tags, and removing some files that are never
used. I verified that the exact same sets of files are compiled on
amd64 GNU/Linux. I also tested the build on i386 Solaris.
Writing match.sh revealed some bugs in the build tag handling that
already exists, in a slightly different form, in the gotest shell
script. This CL fixes those problems as well.
The old code used automake conditionals to handle systems that were
missing strerror_r and wait4. Rather than deal with those in Go, those
functions are now implemented in runtime/go-nosys.c when necessary, so
the Go code can simply assume that they exist.
The os testsuite looked for dir_unix.go, which was never built for gccgo
and has now been removed. I changed the testsuite to look for dir.go
instead.
Reviewed-on: https://go-review.googlesource.com/25546
From-SVN: r239189
When using gccgo on systems without full support for split stacks a
recursive template can overrun the available stack space. Reduce the
limit from 100000 to 10000 to make this less likely. It's still high
enough that real uses will work.
Reviewed-on: https://go-review.googlesource.com/25467
From-SVN: r239141
Leaving them incorrectly marked as addressable broke a use of the
text/template package, because state.evalField checks CanAddr and takes
the address if it is addressable.
Reviewed-on: https://go-review.googlesource.com/21908
From-SVN: r234923
PR go/69966
syscall: Add new Getsockopt functions.
Add GetsockoptICMPv6Filter, GetsockoptIPv6MTUInfo, GetsockoptUcred as
appropriate. These functions exist in the master library.
For GCC PR 69966.
Reviewed-on: https://go-review.googlesource.com/19960
From-SVN: r233747
PR go/66904
cmd/go: fix "#cgo pkg-config:" comments with gccgo
Copy of https://golang.org/cl/18790 by Michael Hudson-Doyle.
The unique difficulty of #cgo pkg-config is that the linker flags are recorded
when the package is compiled but (obviously) must be used when the package is
linked into an executable -- so the flags need to be stored on disk somewhere.
As it happens cgo already writes out a _cgo_flags file: nothing uses it
currently, but this change adds it to the lib$pkg.a file when compiling a
package, reads it out when linking (and passes a version of the .a file with
_cgo_flags stripped out of it to the linker). It's all fairly ugly but it works
and I can't really think of any way of reducing the essential level of
ugliness.
Update golang/go#11739.
GCC PR 66904.
Reviewed-on: https://go-review.googlesource.com/19431
From-SVN: r233290
PR go/65785
net: don't run multicast listen test on nil interface in short mode
This is a backport of https://golang.org/cl/17154.
The gccgo bug report https://gcc.gnu.org/PR65785 points out that the
multicast listen tests will use the network even with -test.short.
Fix test by checking testing.Short with a nil interface.
Reviewed-on: https://go-review.googlesource.com/17158
From-SVN: r230695
When using the go command built from gccgo to build and
install a go tool, use the value from runtime GCCGOTOOLDIR as
the install directory.
This also fixes the output from 'go tool' when used with the
gccgo-built go command, to only include the go tools and not
other binaries found in the same directory.
Reviewed-on: https://go-review.googlesource.com/16516
From-SVN: r230677
PR go/68255
cmd/go: always use --whole-archive for gccgo packages
This is a backport of https://golang.org/cl/16775.
This is, in effect, what the gc toolchain does. It fixes cases where Go
code refers to a C global variable; without this, if the global variable
was the only thing visible in the C code, the generated cgo file might
not get pulled in from the archive, leaving the Go variable
uninitialized.
This was reported against gccgo as https://gcc.gnu.org/PR68255 .
Reviewed-on: https://go-review.googlesource.com/16778
From-SVN: r230120
PR go/66138
reflect, encoding/json, encoding/xml: fix unexported embedded structs
Bring in three changes from the master Go repository. These changes
will be in Go 1.6, but they are appropriate for gccgo now because they
resolve a long-standing discrepancy between how gc and gccgo handle the
PkgPath field for embedded unexported struct fields. The core issue is
described at https://golang.org/cl/7247. This has been reported against
gccgo as https://gcc.gnu.org/PR66138.
The three changes being brought over are:
https://golang.org/cl/14010
reflect: adjust access to unexported embedded structs
This CL changes reflect to allow access to exported fields and
methods in unexported embedded structs for gccgo and after gc
has been adjusted to disallow access to embedded unexported structs.
Adresses #12367, #7363, #11007, and #7247.
https://golang.org/cl/14011
encoding/json: check for exported fields in embedded structs
Addresses issue #12367.
https://golang.org/cl/14012
encoding/xml: check for exported fields in embedded structs
Addresses issue #12367.
Reviewed-on: https://go-review.googlesource.com/16723
From-SVN: r229907
Only build net/hook_cloexec.go on GNU/Linux and FreeBSD, because those
are the only systems with accept4.
Add syscall/libcall_bsd.go to define sendfile for *BSD and Solaris.
Revert tcpsockopt_solaris.go back to the earlier version, so that it
works on Solaris 10.
Always pass the address of a Pid_t value to TIOCGPGRP and TIOCSPGRP.
Include <unistd.h> in runtime/go-varargs.c.
Reviewed-on: https://go-review.googlesource.com/16719
From-SVN: r229880
Type descriptors picked up a zero field because the gc map
implementation used it. However, it's since been dropped by the gc
library. It was never used by gccgo. Drop it now in preparation for
upgrading to the Go 1.5 library.
Reviewed-on: https://go-review.googlesource.com/16486
From-SVN: r229546
Change the type descriptor hash and equal functions from C code pointers
to Go func values. This permits them to be set to a Go function
closure. This is in preparation for the Go 1.5, so that we can use a
closure for the hash/equal functions returned by the new reflect.ArrayOf
function.
Reviewed-on: https://go-review.googlesource.com/16485
From-SVN: r229541
PR go/67874
net, runtime: Call C library fcntl function rather than syscall.Syscall.
Not all systems define a fcntl syscall; some only have fcntl64.
Fixes GCC PR go/67874.
Reviewed-on: https://go-review.googlesource.com/15497
From-SVN: r228576
This avoids linker warnings when linking against glibc, as apparently
arm64 GNU/Linux does not support the ustat system call.
Also update to automake 1.11.6, as that is the new GCC standard.
Reviewed-on: https://go-review.googlesource.com/14567
From-SVN: r227777
The struct RawSockaddr contains a field Data which
should be uint8 on ppc64 and ppc64le, but is declared
as int8 in gccgo. This change adds a two new files
which contain the structure declaration for
RawSockaddr, one with the correct types for for ppc64
and ppc64le, and the other for non-ppc64 platforms.
Fixesgolang/go#11469
Reviewed-on: https://go-review.googlesource.com/11946
From-SVN: r226533
The syscall for Getdents in syscall/libcall_linux.go
called Entersyscall and Exitsyscall, causing the
runtime_sched counts for goroutines to be incorrect.
Inconsistent counts caused checkdead in runtime/proc.c
to panic.
Fixesgolang/go#11406
Reviewed-on: https://go-review.googlesource.com/11761
From-SVN: r225745
PR go/64683
runtime/pprof: Assume function with no name is in runtime.
GCC PR 65797 causes some of the runtime functions to be
compiled with no name in the debug info. This in turn causes
the runtime/pprof test to fail as reported in GCC PR 64683.
There are no good choices when a function has no name in the
debug info, but here we assume that if we see such a function
while reading the runtime functions, we assume that it is also
a runtime function.
From-SVN: r222200
PR go/65755
compiler, runtime, reflect: Use reflection string for type comparisons.
Change the runtime and reflect libraries to always use only
the type reflection string to determine whether two types are
equal. It previously used the PkgPath and Name values for a
type name, but that required a PkgPath that did not match the
gc compiler.
Change the compiler to use the same PkgPath value as the gc
compiler in all cases.
Change the compiler to put the receiver type in the reflection
string for a type defined inside a method.
From-SVN: r222194
When linking complex packages that use both internal and external tests as well as many dependencies it is critical that the link order be external test package, internal test package, everything else.
This change is a back (forward?) port of the same change that canonical have been maintaining on their fork of the go tool for gccgo. Now that gccgo uses the go tool from upstream, this patch should be applied both to the gofrontend and golang/go repos.
From-SVN: r221800
PR go/65417
debug/elf: support reading debug info from 32-bit PPC objects
This is a backport of http://golang.org/7590 from the master
Go library.
From-SVN: r221644
PR go/65462
cmd: Fix dependencies for 'go get' with gccgo
Problem described in GCC BZ 65462.
Generate the list of the standard GO package names based on what was built into libgo in the libgo Makefile.
Change the var name from reqPkgSrc to reqStdPkgSrc to clarify it only affects standard GO packages.
Skip the attempted loading of a package only if it is a standard GO package and the flag is set indicating its source is not required to be available.
This requires a corresponding change to gotools to build and link in the new file containing the list of standard GO package names that was generated by the libgo Makefile.
gotools/:
PR go/65462
* Makefile.am (go_cmd_go_files): Add $(libgodir)/zstdpkglist.go.
* Makefile.in: Rebuild.
From-SVN: r221643
Add memprofilerate as a value recognized
in the GODEBUG env var. The value provided
is used as the new setting for
runtime.MemProfileRate, allowing the user
to adjust memory profiling.
From-SVN: r220470
PR go/64683
runtime/pprof: Let memory profiler test pass if value not collected.
Since gccgo's GC is not precise, the transient value may not
be collected. Let the regexp match that case as well.
From-SVN: r219900
Change from using __go_set_closure to passing the closure
value in the static chain field. Uses new backend support for
setting the closure chain in a call from C via
__builtin_call_with_static_chain. Uses new support in libffi
for Go closures.
The old architecture specific support for reflect.MakeFunc is
removed, replaced by the libffi support.
All work done by Richard Henderson.
* go-gcc.cc (Gcc_backend::call_expression): Add chain_expr argument.
(Gcc_backend::static_chain_variable): New method.
From-SVN: r219776
The version from the master repository seems to be appropriate
for OpenSolaris but not for Solaris itself. Solaris 11.2
proper does not define TCP_KEEPIDLE or TCP_KEEPINTVL.
From-SVN: r219749
This upgrades all of libgo other than the runtime package to
the Go 1.4 release. In Go 1.4 much of the runtime was
rewritten into Go. Merging that code will take more time and
will not change the API, so I'm putting it off for now.
There are a few runtime changes anyhow, to accomodate other
packages that rely on minor modifications to the runtime
support.
The compiler changes slightly to add a one-bit flag to each
type descriptor kind that is stored directly in an interface,
which for gccgo is currently only pointer types. Another
one-bit flag (gcprog) is reserved because it is used by the gc
compiler, but gccgo does not currently use it.
There is another error check in the compiler since I ran
across it during testing.
gotools/:
* Makefile.am (go_cmd_go_files): Sort entries. Add generate.go.
* Makefile.in: Rebuild.
From-SVN: r219627
Don't look it up on PATH. This lets a go tool built as part
of a GCC build use the gccgo from the same build.
Also pass -c when assembling a .s file with gccgo.
From-SVN: r219358
From Dominik Vogt.
* libgo/go/syscall/libcall_linux_s390.go: New file for s390 support.
* libgo/go/syscall/syscall_linux_s390.go: Ditto.
* libgo/go/syscall/libcall_linux_s390x.go: New file for s390x support.
* libgo/go/syscall/syscall_linux_s390x.go: Ditto.
* libgo/go/runtime/pprof/pprof.go (printStackRecord): Support s390 and
s390x.
* libgo/runtime/runtime.c (runtime_cputicks): Add support for s390 and
s390x
* libgo/mksysinfo.sh: Ditto.
(upcase_fields): New helper function
* libgo/go/debug/elf/file.go (applyRelocations): Implement relocations
on s390x.
(applyRelocationsS390x): Ditto.
(DWARF): Ditto.
* libgo/go/debug/elf/elf.go (R_390): New constants for S390 relocations.
(r390Strings): Ditto.
(String): Helper function for S390 relocations.
(GoString): Ditto.
* libgo/go/reflect/makefuncgo_s390.go: New file.
(S390MakeFuncStubGo): Implementation of s390 abi.
* libgo/go/reflect/makefuncgo_s390x.go: New file.
(S390xMakeFuncStubGo): Implementation of s390x abi.
* libgo/go/reflect/makefunc_s390.c: New file.
(makeFuncStub): s390 and s390x specific implementation of function.
* libgo/go/reflect/makefunc.go
(MakeFunc): Add support for s390 and s390x.
(makeMethodValue): Ditto.
(makeValueMethod): Ditto.
* libgo/Makefile.am (go_reflect_makefunc_s_file): Ditto.
(go_reflect_makefunc_file): Ditto.
* libgo/go/reflect/makefunc_dummy.c: Ditto.
* libgo/runtime/runtime.h (__go_makefunc_can_recover): Export prototype
for use in makefunc_s390.c.
(__go_makefunc_returning): Ditto.
* libgo/go/syscall/exec_linux.go (forkAndExecInChild): Fix order of the
arguments of the clone system call for s390[x].
* libgo/configure.ac (is_s390): New variable.
(is_s390x): Ditto
(LIBGO_IS_S390): Ditto.
(LIBGO_IS_S390X): Ditto.
(GOARCH): Support s390 and s390x.
* libgo/go/go/build/build.go (cgoEnabled): Ditto.
* libgo/go/go/build/syslist.go (goarchList): Ditto.
From-SVN: r217106
Backport https://codereview.appspot.com/155450044 from the
master Go library. Original description:
I came across this while debugging a GC problem in gccgo.
There is code in assignTo and cvtT2I that handles assignment
to all interface values. It allocates an empty interface even
if the real type is a non-empty interface. The fields are
then set for a non-empty interface, but the memory is recorded
as holding an empty interface. This means that the GC has
incorrect information.
This is extremely unlikely to fail, because the code in the GC
that handles empty interfaces looks like this:
obj = nil;
typ = eface->type;
if(typ != nil) {
if(!(typ->kind&KindDirectIface) || !(typ->kind&KindNoPointers))
obj = eface->data;
In the current runtime the condition is always true--if
KindDirectIface is set, then KindNoPointers is clear--and we
always want to set obj = eface->data. So the question is what
happens when we incorrectly store a non-empty interface value
in memory marked as an empty interface. In that case
eface->type will not be a *rtype as we expect, but will
instead be a pointer to an Itab. We are going to use this
pointer to look at a *rtype kind field. The *rtype struct
starts out like this:
type rtype struct {
size uintptr
hash uint32 // hash of type; avoids computation in hash tables
_ uint8 // unused/padding
align uint8 // alignment of variable with this type
fieldAlign uint8 // alignment of struct field with this type
kind uint8 // enumeration for C
An Itab always has at least two pointers, so on a
little-endian 64-bit system the kind field will be the high
byte of the second pointer. This will normally be zero, so
the test of typ->kind will succeed, which is what we want.
On a 32-bit system it might be possible to construct a failing
case by somehow getting the Itab for an interface with one
method to be immediately followed by a word that is all ones.
The effect would be that the test would sometimes fail and the
GC would not mark obj, leading to an invalid dangling
pointer. I have not tried to construct this test.
I noticed this in gccgo, where this error is much more likely
to cause trouble for a rather random reason: gccgo uses a
different layout of rtype, and in gccgo the kind field happens
to be the low byte of a pointer, not the high byte.
From-SVN: r216489
PR go/60406
runtime: Check callers in can_recover if return address doesn't match.
Also use __builtin_extract_return_address and tighten up the
checks in FFI code.
Fixes PR 60406.
From-SVN: r216003
PR go/61877
refect: fix direct call of variadic method value
As reported in bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61877
gcc mainline has regressed in this. This CL adds the tests proposed
for the main Go repository:
https://codereview.appspot.com/151280043/https://codereview.appspot.com/152060043/
restores the code from the amd64/386 path that makes this work and
was lost when the Go 1.3 stdlib was merged and changes the FFI path
to call into the same helper code as the amd64/386 path.
I've only tested this on amd64 but I did test a version that was
patched to unconditionally take the FFI path.
From-SVN: r215859
This variable is unused apparently as a result of local changes.
gccgo accepts this variable declaration, but other frontends may not.
From-SVN: r212873
Ian Lance Taylor