In Go 1.19, we develop register ABI for riscv64, enabled by default as a
GOEXPERIMENT. We can turn it on all the time in Go 1.20.
Change-Id: Ie8e2ac8b8bd3ebddb0dc6d58a5599547fb440e03
Reviewed-on: https://go-review.googlesource.com/c/go/+/443555
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go/build and cmd/go will stop returing Targets for stdlib .a files, and
stop producing the .a files is pkg/GOOS_GOARCH. update tests to
anticipate that and to pass in importcfgs instead of expecting the
compiler can find .a files in their old locations.
Adds code to determine locations of .a files to internal/goroot. Also
adds internal/goroot to dist's bootstrap directories and changes
internal/goroot to build with a bootstrap version of Go.
Change-Id: Ie81e51105bddb3f0e374cbf47e81c23edfb67fa5
Reviewed-on: https://go-review.googlesource.com/c/go/+/442303
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Add the riscv64 register ABI constants and allow regabi
value to be set for riscv64
Change-Id: I3ce98bf9a29d2acc00f92650b27bc59884ed62ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/359336
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In last cycle we developed register ABI for ARM64, enabled by
default as a GOEXPERIMENT. This cycle we turn it on all the time.
Later CLs will clean up fallback code.
Change-Id: Idac4dcff634791cbc3d30988052ecd742b55ab8b
Reviewed-on: https://go-review.googlesource.com/c/go/+/394214
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In last cycle we developed register ABI for ARM64, enabled by
default as a GOEXPERIMENT. This cycle we turn it on all the time.
Later CLs will clean up fallback code.
To support in-development platforms (e.g. RISC-V), separate the
boolean variables for in-development platforms and always-on
platforms.
Change-Id: I97c27f6aeccc85ccc57eed2abd783b176da3ad80
Reviewed-on: https://go-review.googlesource.com/c/go/+/393364
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regabireflect goexperiment was helpful in the register ABI
development, to control code paths for reflect calls, before the
compiler can generate register ABI everywhere. It is not necessary
for now. Drop it.
Change-Id: I2731197d2f496e29616c426a01045c9b685946a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/393362
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The -p flag specifies the import path of the package being compiled.
This CL makes it required when invoking the compiler and
adjusts tests that invoke the compiler directly to conform to this
new requirement. The go command already passes the flag, so it
is unmodified in this CL. It is expected that any other Go build systems
also already pass -p, or else they will need to arrange to do so before
updating to Go 1.19. Of particular note, Bazel already does for rules
with an importpath= attribute, which includes all Gazelle-generated rules.
There is more cleanup possible now in cmd/compile, cmd/link,
and other consumers of Go object files, but that is left to future CLs.
Additional historical background follows but can be ignored.
Long ago, before the go command, or modules, or any kind of
versioning, symbols in Go archive files were named using just the
package name, so that for example func F in math/rand and func F in
crypto/rand would both be the object file symbol 'rand.F'. This led to
collisions even in small source trees, which made certain packages
unusable in the presence of other packages and generally was a problem
for Go's goal of scaling to very large source trees.
Fixing this problem required changing from package names to import
paths in symbol names, which was mostly straightforward. One wrinkle,
though, is that the compiler did not know the import path of the
package being compiled; it only knew the package name. At the time,
there was no go command, just Makefiles that people had invoking 6g
(now “go tool compile”) and then copying the resulting object file to
an importable location. That is, everyone had a custom build setup for
Go, because there was no standard one. So it was not particularly
attractive to change how the compiler was invoked, since that would
break approximately every Go user at the time. Instead, we arranged
for the compiler to emit, and other tools reading object files to
recognize, a special import path (the empty string, it turned out)
denoting “the import path of this object file”. This worked well
enough at the time and maintained complete command-line compatibility
with existing Go usage.
The changes implementing this transition can be found by searching
the Git history for “package global name space”, which is what they
eliminated. In particular, CL 190076 (a6736fa4), CL 186263 (758f2bc5),
CL 193080 (1cecac81), CL 194053 (19126320), and CL 194071 (531e6b77)
did the bulk of this transformation in January 2010.
Later, in September 2011, we added the -p flag to the compiler for
diagnostic purposes. The problem was that it was easy to create import
cycles, especially in tests, and these could not be diagnosed until
link time. You'd really want the compiler to diagnose these, for
example if the compilation of package sort noticed it was importing a
package that itself imported "sort". But the compilation of package
sort didn't know its own import path, and so it could not tell whether
it had found itself as a transitive dependency. Adding the -p flag
solved this problem, and its use was optional, since the linker would
still diagnose the import cycle in builds that had not updated to
start passing -p. This was CL 4972057 (1e480cd1).
There was still no go command at this point, but when we introduced
the go command we made it pass -p, which it has for many years at this
point.
Over time, parts of the compiler began to depend on the presence of
the -p flag for various reasonable purposes. For example:
In CL 6497074 (041fc8bf; Oct 2012), the race detector used -p to
detect packages that should not have race annotations, such as
runtime/race and sync/atomic.
In CL 13367052 (7276c02b; Sep 2013), a bug fix used -p to detect the
compilation of package reflect.
In CL 30539 (8aadcc55; Oct 2016), the compiler started using -p to
identify package math, to be able to intrinsify calls to Sqrt inside
that package.
In CL 61019 (9daee931; Sep 2017), CL 71430 (2c1d2e06; Oct 2017), and
later related CLs, the compiler started using the -p value when
creating various DWARF debugging information.
In CL 174657 (cc5eaf93; May 2019), the compiler started writing
symbols without the magic empty string whenever -p was used, to reduce
the amount of work required in the linker.
In CL 179861 (dde7c770; Jun 2019), the compiler made the second
argument to //go:linkname optional when -p is used, because in that
case the compiler can derive an appropriate default.
There are more examples. Today it is impossible to compile the Go
standard library without using -p, and DWARF debug information is
incomplete without using -p.
All known Go build systems pass -p. In particular, the go command
does, which is what nearly all Go developers invoke to build Go code.
And Bazel does, for go_library rules that set the importpath
attribute, which is all rules generated by Gazelle.
Gccgo has an equivalent of -p and has required its use in order to
disambiguate packages with the same name but different import paths
since 2010.
On top of all this, various parts of code generation for generics
are made more complicated by needing to cope with the case where -p
is not specified, even though it's essentially always specified.
In summary, the current state is:
- Use of the -p flag with cmd/compile is required for building
the standard library, and for complete DWARF information,
and to enable certain linker speedups.
- The go command and Bazel, which we expect account for just
about 100% of Go builds, both invoke cmd/compile with -p.
- The code in cmd/compile to support builds without -p is
complex and has become more complex with generics, but it is
almost always dead code and therefore not worth maintaining.
- Gccgo already requires its equivalent of -p in any build
where two packages have the same name.
All this supports the change in this CL, which makes -p required
and adjusts tests that invoke cmd/compile to add -p appropriately.
Future CLs will be able to remove all the code dealing with the
possibility of -p not having been specified.
Change-Id: I6b95b9d4cffe59c7bac82eb273ef6c4a67bb0e43
Reviewed-on: https://go-review.googlesource.com/c/go/+/391014
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And then revert the bootstrap cmd directories and certain testdata.
And adjust tests as needed.
Not reverting the changes in std that are bootstrapped,
because some of those changes would appear in API docs,
and we want to use any consistently.
Instead, rewrite 'any' to 'interface{}' in cmd/dist for those directories
when preparing the bootstrap copy.
A few files changed as a result of running gofmt -w
not because of interface{} -> any but because they
hadn't been updated for the new //go:build lines.
Fixes#49884.
Change-Id: Ie8045cba995f65bd79c694ec77a1b3d1fe01bb09
Reviewed-on: https://go-review.googlesource.com/c/go/+/368254
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When register ABI is used, reflect.Value.Call prepares the call
arguments in a memory representation of the argument registers.
It has special handling to keep the pointers in arguments live.
Currently, this handles pointer-typed arguments. But when an
argument is an aggregate-type that contains pointers and passed
in registers, it currently doesn't keep the pointers live. Do
so in this CL.
May fix#49363.
Change-Id: Ic6a0c5fdf9375ef02f7c03fbe9345e2e98c9353d
Reviewed-on: https://go-review.googlesource.com/c/go/+/363358
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When these packages are released as part of Go 1.18,
Go 1.16 will no longer be supported, so we can remove
the +build tags in these files.
Ran go fix -fix=buildtag std cmd and then reverted the bootstrapDirs
as defined in src/cmd/dist/buildtool.go, which need to continue
to build with Go 1.4 for now.
Also reverted src/vendor and src/cmd/vendor, which will need
to be updated in their own repos first.
Manual changes in runtime/pprof/mprof_test.go to adjust line numbers.
For #41184.
Change-Id: Ic0f93f7091295b6abc76ed5cd6e6746e1280861e
Reviewed-on: https://go-review.googlesource.com/c/go/+/344955
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Add the PPC64 register ABI constants, and allow
GOEXPERIMENT regabi values to be set for PPC64.
Change-Id: I1c9562ae6669c604db69a7b8ad935d1bc117c899
Reviewed-on: https://go-review.googlesource.com/c/go/+/343870
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Currently on amd64 and arm64, float32 values just live in the bottom 32
bits of the register, so reflect simply places them there in a RegArgs
for reflectcall to load them. This works fine because both of these
platforms don't care what the upper 32 bits are, and have instructions
to operate on float32 values specifically that we use. In sum, the
representation of the float32 in memory is identical to that of the
representation in a register.
On other platforms, however, the representation of FP values differ
depending on whether they're in memory or in a register. For instance,
on ppc64, all floating point values get promoted to a float64 when
loaded to a register (i.e. there's only one set of FP instructions). As
another example, on riscv64, narrow-width floats in registers need to be
NaN-boxed.
What all this means is that for supporting the register ABI on these
platforms, reflect needs to do a little extra work to ensure that the
representation of FP values in a RegArgs matches the representation it
takes on in a register. For this purpose, this change abstracts away the
action of storing values into a RegArgs a little bit and adds a
platform-specific hook which currently does nothing but copy the value.
For #40724.
Change-Id: I65dcc7d86d5602a584f86026ac204564617f4c5a
Reviewed-on: https://go-review.googlesource.com/c/go/+/347566
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In Go 1.17 we added register ABI on AMD64 on Linux/macOS/Windows
as a GOEXPERIMENT, on by default. In Go 1.18, we commit to always
enabling register ABI on AMD64.
Now "go build" for AMD64 always have goexperiment.regabi* tags
set. However, at bootstrapping cmd/dist does not set the tags
when building go_bootstrap. For this to work, unfortunately, we
need to hard-code AMD64 to use register ABI in runtime code.
Change-Id: I0b31e678e186b9cdeeb8502cd9e38ed0d7e72d4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/341151
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Currently, callMethod has some ABI translation code that is not agnostic
of endianness. This change rectifies that by adding a method to
internal/abi.RegArgs for safely returning an offset into a register slot
that's endianness-dependent.
No tests for this because it's just best-effort. There's no actual way
to test this because we don't support a register ABI on any big endian
architectures yet.
Change-Id: Ic68d9ee1bfdea0fc2992d467d749e2b083e92de3
Reviewed-on: https://go-review.googlesource.com/c/go/+/328348
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Change-Id: I9cdf0f2b6c1739f13a859a8e37351f8ecd77804a
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When ABI wrappers are used, there are cases where in Go code we
need the PC of the defined function instead of the ABI wrapper.
Currently we work around this by define such functions as
ABIInternal, even if they do not actually follow the internal ABI.
This CL introduces internal/abi.FuncPCABIxxx functions as compiler
intrinsics, which return the underlying defined function's entry
PC if the argument is a direct reference of a function of the
expected ABI, and reject it if it is of a different ABI.
As a proof of concept, change runtime.goexit back to ABI0 and use
internal/abi.FuncPCABI0 to retrieve its PC.
Updates #44065.
Change-Id: I02286f0f9d99e6a3090f9e8169dbafc6804a2da6
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This separates GOEXPERIMENT=regabi into five sub-experiments:
regabiwrappers, regabig, regabireflect, regabidefer, and regabiargs.
Setting GOEXPERIMENT=regabi now implies the working subset of these
(currently, regabiwrappers, regabig, and regabireflect).
This simplifies testing, helps derisk the register ABI project,
and will also help with performance comparisons.
This replaces the -abiwrap flag to the compiler and linker with
the regabiwrappers experiment.
As part of this, regabiargs now enables registers for all calls
in the compiler. Previously, this was statically disabled in
regabiEnabledForAllCompilation, but now that we can control it
independently, this isn't necessary.
For #40724.
Change-Id: I5171e60cda6789031f2ef034cc2e7c5d62459122
Reviewed-on: https://go-review.googlesource.com/c/go/+/302070
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This change switches reflect to use global variables for ABI-related
register counts instead of internal/abi constants. The advantage of
doing so is that we can make the internal/abi constants non-zero and
enable the runtime register argument spiller/unspiller even if they're
not used. It's basically turning two things we need to flip when we
switch to the register ABI into one.
It also paves the way for testing the reflect register ABI path
independently, because now we can switch the global variables at will
and run the register-assignment algorithm in tests without having the
rest of the runtime be broken.
Change-Id: Ie23629a37a5c80aeb24909d4bd9eacbd3f0c06d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/293149
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Make all our package sources use Go 1.17 gofmt format
(adding //go:build lines).
Part of //go:build change (#41184).
See https://golang.org/design/draft-gobuild
Change-Id: Ia0534360e4957e58cd9a18429c39d0e32a6addb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/294430
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This change sets the register count constants to zero for the
GOEXPERIMENT regabi because currently the users of it (i.e. reflect)
will be broken, since they expect Go functions that implement the new
ABI.
Change-Id: Id3e874c61821a36605eb4e1cccdee36a2759f303
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This change adds support for the new register ABI on amd64 to
reflect.(Value).Call. If internal/abi's register counts are non-zero,
reflect will try to set up arguments in registers on the Call path.
Note that because the register ABI becomes ABI0 with zero registers
available, this should keep working as it did before.
This change does not add any tests for the register ABI case because
there's no way to do so at the moment.
For #40724.
Change-Id: I8aa089a5aa5a31b72e56b3d9388dd3f82203985b
Reviewed-on: https://go-review.googlesource.com/c/go/+/272568
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This change creates a new internal std package internal/abi which is
intended to hold constants with platform-specific values related to
our ABI that is useful to different std packages, such as runtime and
reflect.
For #40724.
Change-Id: Ie7ae7f687629cd3d613ba603e9371f0887601fe6
Reviewed-on: https://go-review.googlesource.com/c/go/+/272567
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Reviewed-by: Austin Clements <austin@google.com>
Wayne Zuo
Michael Matloob
Meng Zhuo
Cherry Mui
Russ Cox
Lynn Boger
Michael Anthony Knyszek
Austin Clements