Along the way, track bad modules. Make sure they don't end up on
the active modules list, and aren't accidentally reprocessed as
new plugins.
Fixes#19004
Change-Id: I8a5e7bb11f572f7b657a97d521a7f84822a35c07
Reviewed-on: https://go-review.googlesource.com/61171
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
I noticed that we don't set an itab's function pointers at compile
time. Instead, we currently do it at executable startup.
Set the function pointers at compile time instead. This shortens
startup time. It has no effect on normal binary size. Object files
will have more relocations, but that isn't a big deal.
For PIE there are additional pointers that will need to be adjusted at
load time. There are already other pointers in an itab that need to be
adjusted, so the cache line will already be paged in. There might be
some binary size overhead to mark these pointers. The "go test -c
-buildmode=pie net/http" binary is 0.18% bigger.
Update #20505
Change-Id: I267c82489915b509ff66e512fc7319b2dd79b8f7
Reviewed-on: https://go-review.googlesource.com/44341
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Keep itabs in a growable hash table.
Use a simple open-addressable hash table, quadratic probing, power
of two sized.
Synchronization gets a bit more tricky. The common read path now
has two atomic reads, one to get the table pointer and one to read
the entry out of the table.
I set the max load factor to 75%, kind of arbitrarily. There's a
space-speed tradeoff here, and I'm not sure where we should land.
Because we use open addressing the itab.link field is no longer needed.
I'll remove it in a separate CL.
Fixes#20505
Change-Id: Ifb3d9a337512d6cf968c1fceb1eeaf89559afebf
Reviewed-on: https://go-review.googlesource.com/44472
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Currently almost every function that deals with a *_func has to first
look up the *moduledata for the module containing the function's entry
point. This means we almost always do at least two identical module
lookups whenever we deal with a *_func (one to get the *_func and
another to get something from its module data) and sometimes several
more.
Fix this by making findfunc return a new funcInfo type that embeds
*_func, but also includes the *moduledata, and making all of the
functions that currently take a *_func instead take a funcInfo and use
the already-found *moduledata.
This transformation is trivial for the most part, since the *_func
type is usually inferred. The annoying part is that we can no longer
use nil to indicate failure, so this introduces a funcInfo.valid()
method and replaces nil checks with calls to valid.
Change-Id: I9b8075ef1c31185c1943596d96dec45c7ab5100f
Reviewed-on: https://go-review.googlesource.com/37331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
When doing i.(T) for non-empty-interface i and concrete type T,
there's no need to read the type out of the itab. Just compare the
itab to the itab we expect for that interface/type pair.
Also optimize type switches by putting the type hash of the
concrete type in the itab. That way we don't need to load the
type pointer out of the itab.
Update #18492
Change-Id: I49e280a21e5687e771db5b8a56b685291ac168ce
Reviewed-on: https://go-review.googlesource.com/34810
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
We already do this for shared libraries. Do it for plugins also.
Suggestions on how to test this would be welcome.
I'd like to get this in for 1.8. It could lead to mysterious
hangs when using plugins.
Fixes#18676
Change-Id: I03209b096149090b9ba171c834c5e59087ed0f92
Reviewed-on: https://go-review.googlesource.com/35117
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Explicitly filter any C-only cgo functions out of pclntable,
which allows them to be duplicated with the host binary.
Updates #18190.
Change-Id: I50d8706777a6133b3e95f696bc0bc586b84faa9e
Reviewed-on: https://go-review.googlesource.com/34199
Reviewed-by: Ian Lance Taylor <iant@golang.org>
In plugins and every program that opens a plugin, include a hash of
every imported package.
There are two versions of each hash: one local and one exported.
As the program starts and plugins are loaded, the first exported
symbol for each package becomes the canonical version.
Any subsequent plugin's local package hash symbol has to match the
canonical version.
Fixes#17832
Change-Id: I4e62c8e1729d322e14b1673bada40fa7a74ea8bc
Reviewed-on: https://go-review.googlesource.com/33161
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The introduction of -buildmode=plugin means modules can be added to a
Go program while it is running. This means there exists some time
while the program is running with the module is on the moduledata
linked list, but it has not been initialized to the satisfaction of
other parts of the runtime. Notably, the GC.
This CL adds a new way of access modules, an activeModules function.
It returns a slice of modules that is built in the background and
atomically swapped in. The parts of the runtime that need to wait on
module initialization can use this slice instead of the linked list.
Fixes#17455
Change-Id: I04790fd07e40c7295beb47cea202eb439206d33d
Reviewed-on: https://go-review.googlesource.com/32357
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Plumb the import path of a plugin package through to the linker, and
use it as the prefix on the exported symbol names.
Before this we used the basename of the plugin file as the prefix,
which could conflict and result in multiple loaded plugins sharing
symbols that are distinct.
Fixes#17155Fixes#17579
Change-Id: I7ce966ca82d04e8507c0bcb8ea4ad946809b1ef5
Reviewed-on: https://go-review.googlesource.com/32355
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Inspired by difficulties with plugin support on darwin.
Change-Id: I2cef8410837946454e75d00e94e46791f03f2267
Reviewed-on: https://go-review.googlesource.com/29391
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Includes a linux implementation.
Change-Id: Iacc2ed7da760ae9deebc928adf2b334b043b07ec
Reviewed-on: https://go-review.googlesource.com/27823
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL contains several linker changes to support creating plugins.
It collects the exported plugin symbols provided by the compiler and
includes them in the moduledata.
It treats a binary as being dynamically linked if it imports the plugin
package. This lets the dynamic linker de-duplicate symbols.
Change-Id: I099b6f38dda26306eba5c41dbe7862f5a5918d95
Reviewed-on: https://go-review.googlesource.com/27820
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
David Crawshaw
Keith Randall
Austin Clements