SB register (R28) is introduced for access external addresses with shorter
instruction sequences. It is loaded at entry points. External data within
2G of SB can be accessed this way.
cmd/internal/obj: relocaltion R_ADDRMIPS is split into two relocations
R_ADDRMIPS and R_ADDRMIPSU, handling the low 16 bits and the "upper" 16
bits of external addresses, respectively, since the instructios may not
be adjacent. It might be better if relocation Variant could be used.
cmd/link/internal/mips64: support new relocations.
cmd/compile/internal/mips64: reserve SB register.
runtime: initialize SB register at entry points.
Change-Id: I5f34868f88c5a9698c042a8a1f12f76806c187b9
Reviewed-on: https://go-review.googlesource.com/19802
Reviewed-by: Minux Ma <minux@golang.org>
golang.org/cl/22453 was supposed to pass -no-pie to the linker when linking a
race-enabled binary if the host toolchain supports it. But I bungled the
supported check as I forgot to pass -c to the host compiler so it tried to
compile a 0 byte .c file into an executable, which will never work. Fix it to
pass -c as it should have all along.
Change-Id: I4801345c7a29cb18d5f22cec5337ce535f92135d
Reviewed-on: https://go-review.googlesource.com/22587
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Now it is possible to build a c-archive as PIC on darwin/arm (this is
now the default). Then the system linker can link the binary using
the archive as PIE.
Fixes#12896.
Change-Id: Iad84131572422190f5fa036e7d71910dc155f155
Reviewed-on: https://go-review.googlesource.com/22461
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also adds TestGdbBacktrace to the runtime package.
Dwarf modifications written by Bryan Chan (@bryanpkc) who is also
at IBM and covered by the same CLA.
Fixes#14628
Change-Id: I106a1f704c3745a31f29cdadb0032e3905829850
Reviewed-on: https://go-review.googlesource.com/20193
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The linker was incorrectly decoding type name lengths, causing
typelinks to be sorted out of order and in cases where the name was
the exact right length, linker panics.
Added a test to the reflect package that causes TestTypelinksSorted
to fail before this CL. It's not the exact failure seen in #15448
but it has the same cause: decodetype_name calculating the wrong
length.
The equivalent decoders in reflect/type.go and runtime/type.go
have the parenthesis in the right place.
Fixes#15448
Change-Id: I33257633d812b7d2091393cb9d6cc8a73e0138c8
Reviewed-on: https://go-review.googlesource.com/22403
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Now that reflect.name objects contain an offset to pkgPath instead of a
pointer, there is no need to align the symbol data.
Removes approx. 10KB from the cmd/go binary. The effect becomes more
important later as more type data is moved into name objects.
For #6853
Change-Id: Idb507fdbdad04f16fc224378f82272cb5c236ab7
Reviewed-on: https://go-review.googlesource.com/21776
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Does anyone actually pass -a to the linker?
Change-Id: I1d31ea66aa5604b7fd42adf15bdab71e9f52d0ed
Reviewed-on: https://go-review.googlesource.com/22356
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reduces link time for cmd/go by 1%.
Change-Id: Iad4a16db0aedc56f81ddf73ba9b632e418dc1b19
Reviewed-on: https://go-review.googlesource.com/22242
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
For the Solaris and S/390 builders.
Change-Id: Id9a83e0df91e6d0df8488ec5e2a546ba8e2d800e
Reviewed-on: https://go-review.googlesource.com/22327
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
First (and largest single) step to switching cmd/link from linked
lists of symbols to slices.
Sort sections independently and concurrently.
This reduces jujud link times on linux/amd64 by ~4%.
Updates #15374
Change-Id: I452bc8f33081039468636502fe3c1cc8d6ed9efa
Reviewed-on: https://go-review.googlesource.com/22205
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Use (part of) a SHA-1 checksum to replace type symbol names.
In typical programs this has no effect because types are not included
in the symbol table. But when dynamically linking, types are in the
table to make sure there is only one *rtype per Go type.
Eventually we may be able to get rid of all pointers to rtype values in
the binary, but probably not by 1.7. And this has a nice effect on
binary size today:
libstd.so:
before 27.4MB
after 26.2MB
For #6853.
Change-Id: I603d7f3e5baad84f59f2fd37eeb1e4ae5acfe44a
Reviewed-on: https://go-review.googlesource.com/21583
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Instead of writing out the type almost twice in the symbol name,
teach the linker how to sort typelink symbols by their contents.
This ~halves the size of typelink symbol names, which helps very
large (6KB) names like those mentioned in #15104.
This does not increase the total sorting work done by the linker,
and makes it possible to use shorter symbol names for types. See
the follow-on CL 21583.
Change-Id: Ie5807565ed07d31bc477d20f60e4c0b47144f337
Reviewed-on: https://go-review.googlesource.com/21457
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The GNU linker follows the letter of -znocopyreloc by refusing to
generate COPY relocations on arm64. Unfortunately it generates an
error instead of finding another way. The gold linker works, so
switch to it.
Fixes linux/arm64 build.
Change-Id: I1f7119d999c8f9f1f2d0c1e06b6462cea9c02a71
Reviewed-on: https://go-review.googlesource.com/22185
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Introduce and start using nameOff for two encoded names. This pair
of changes is best done together because the linker's method decoder
expects the method layouts to match.
Precursor to converting all existing name and *string fields to
nameOff.
linux/amd64:
cmd/go: -45KB (0.5%)
jujud: -389KB (0.6%)
linux/amd64 PIE:
cmd/go: -170KB (1.4%)
jujud: -1.5MB (1.8%)
For #6853.
Change-Id: Ia044423f010fb987ce070b94c46a16fc78666ff6
Reviewed-on: https://go-review.googlesource.com/21396
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL introduces the typeOff type and a lookup method of the same
name that can turn a typeOff offset into an *rtype.
In a typical Go binary (built with buildmode=exe, pie, c-archive, or
c-shared), there is one moduledata and all typeOff values are offsets
relative to firstmoduledata.types. This makes computing the pointer
cheap in typical programs.
With buildmode=shared (and one day, buildmode=plugin) there are
multiple modules whose relative offset is determined at runtime.
We identify a type in the general case by the pair of the original
*rtype that references it and its typeOff value. We determine
the module from the original pointer, and then use the typeOff from
there to compute the final *rtype.
To ensure there is only one *rtype representing each type, the
runtime initializes a typemap for each module, using any identical
type from an earlier module when resolving that offset. This means
that types computed from an offset match the type mapped by the
pointer dynamic relocations.
A series of followup CLs will replace other *rtype values with typeOff
(and name/*string with nameOff).
For types created at runtime by reflect, type offsets are treated as
global IDs and reference into a reflect offset map kept by the runtime.
darwin/amd64:
cmd/go: -57KB (0.6%)
jujud: -557KB (0.8%)
linux/amd64 PIE:
cmd/go: -361KB (3.0%)
jujud: -3.5MB (4.2%)
For #6853.
Change-Id: Icf096fd884a0a0cb9f280f46f7a26c70a9006c96
Reviewed-on: https://go-review.googlesource.com/21285
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
After non pcln fields were added to it in a previous commit.
Change-Id: Icf92c0774d157c61399a6fc2a3c4d2cd47a634d2
Reviewed-on: https://go-review.googlesource.com/21921
Run-TryBot: Shahar Kohanim <skohanim@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
name old secs new secs delta
LinkCmdGo 0.53 ± 9% 0.53 ±10% -1.30% (p=0.022 n=100+99)
name old MaxRSS new MaxRSS delta
LinkCmdGo 151k ± 4% 142k ± 6% -5.92% (p=0.000 n=98+100)
Change-Id: Ic30e63a948f8e626b3396f458a0163f7234810c1
Reviewed-on: https://go-review.googlesource.com/21920
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is the first in a series of CLs to replace the use of pointers
in binary read-only data with offsets.
In standard Go binaries these CLs have a small effect, shrinking
8-byte pointers to 4-bytes. In position-independent code, it also
saves the dynamic relocation for the pointer. This has a significant
effect on the binary size when building as PIE, c-archive, or
c-shared.
darwin/amd64:
cmd/go: -12KB (0.1%)
jujud: -82KB (0.1%)
linux/amd64 PIE:
cmd/go: -86KB (0.7%)
jujud: -569KB (0.7%)
For #6853.
Change-Id: Iad5625bbeba58dabfd4d334dbee3fcbfe04b2dcf
Reviewed-on: https://go-review.googlesource.com/21284
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Workaround external linking issues encountered on Solaris 11.2+ due to
the go.o object file being created with a NULL STT_FILE symtab entry by
using a placeholder name.
Fixes#14957
Change-Id: I89c501b4c548469f3c878151947d35588057982b
Reviewed-on: https://go-review.googlesource.com/21636
Reviewed-by: David Crawshaw <crawshaw@golang.org>
After making dwarf generation backed by LSyms there was a performance regression
of about 10%. These changes make on the fly symbol generation faster and
are meant to help mitigate that.
name old secs new secs delta
LinkCmdGo 0.55 ± 9% 0.53 ± 8% -4.42% (p=0.000 n=100+99)
name old MaxRSS new MaxRSS delta
LinkCmdGo 152k ± 6% 149k ± 3% -1.99% (p=0.000 n=99+97)
Change-Id: Iacca3ec924ce401aa83126bc0b10fe89bedf0ba6
Reviewed-on: https://go-review.googlesource.com/21733
Run-TryBot: Shahar Kohanim <skohanim@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Replace calls to bio.Bread with calls to io.ReadFull.
Change-Id: I2ee8739d01e04a4da9c20b6ce7d1d5b89914b8ad
Reviewed-on: https://go-review.googlesource.com/21750
Reviewed-by: Dave Cheney <dave@cheney.net>
Generated with honnef.co/go/unused
There is a large amount of unused code in cmd/internal/obj/s390x but
that can wait til the s390x port is merged.
There is some unused code in
cmd/internal/unvendor/golang.org/x/arch/arm/armasm but that should be
addressed upstream and a new revision imported.
Change-Id: I252c0f9ea8c5bb1a0b530a374ef13a0a20ea56aa
Reviewed-on: https://go-review.googlesource.com/21782
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
bio.BufReader was never used.
bio.BufWriter was used to wrap an existing io.Writer, but the
bio.Writer returned would not be seekable, so replace all occurences
with bufio.Reader instead.
Change-Id: I9c6779e35c63178aa4e104c17bb5bb8b52de0359
Reviewed-on: https://go-review.googlesource.com/21722
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is a pre requesite of CL 21722 and removes a lot of unidiomatic
boilerplate in the linker.
Change-Id: If7491b88212b2be7b0c8c588e9c196839131f8ad
Reviewed-on: https://go-review.googlesource.com/21780
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Replace the bidirectional bio.Buf type with a pair of unidirectional
buffered seekable Reader and Writers.
Change-Id: I86664a06f93c94595dc67c2cbd21356feb6680ef
Reviewed-on: https://go-review.googlesource.com/21720
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
API could still be made more Go-ey.
Updates #15165.
Change-Id: I514ffceffa43c293ae5d7e5f1e9193fda0098865
Reviewed-on: https://go-review.googlesource.com/21644
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
