When building shared libraries, all symbols on Allsym are marked reachable.
What I didn't realize was that this includes the ".dup" symbols created when
"dupok" symbols are read from multiple package files. This breaks now because
deadcode makes some assumptions that fail for these ".dup" symbols, but in any
case was a bad idea -- I suspect this change makes libstd.so a bunch smaller,
but creating it was broken before this CL so I can't be sure.
This change simply stops adding these symbols to Allsym, which might make some
of the many iterations over Allsym the linker does a touch quicker, although
that's not the motivation here.
Add a test that no symbols called ".dup" makes it into the runtime shared
library.
Fixes#14841
Change-Id: I65dd6e88d150a770db2d01b75cfe5db5fd4f8d25
Reviewed-on: https://go-review.googlesource.com/20780
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The type information for a method includes two variants: a func
without the receiver, and a func with the receiver as the first
parameter. The former is used as part of the dynamic interface
checks, but the latter is only returned as a type in the
reflect.Method struct.
Instead of computing it at compile time, construct it at run time
with reflect.FuncOf.
Using cl/20701 as a baseline,
cmd/go: -480KB, (4.4%)
jujud: -5.6MB, (7.8%)
For #6853.
Change-Id: I1b8c73f3ab894735f53d00cb9c0b506d84d54e92
Reviewed-on: https://go-review.googlesource.com/20709
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Remove method type information for pruned methods from any program
that does not reflect on methods. This can be a significant saving:
addr2line: -310KB (8.8%)
A future update might want to consider a more aggressive variant of
this: setting the Type and Func fields of reflect.Method to nil for
unexported methods. That would shrink cmd/go by 2% and jujud by 2.6%
but could be considered an API change. So this CL sticks to the
uncontroversial change.
For #6853.
Change-Id: I5d186d9f822dc118ee89dc572c4912a3b3c72577
Reviewed-on: https://go-review.googlesource.com/20701
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Symbols in the object file currently refer to each other using symbol name
and version. Referring to the same symbol many times in an object file takes
up space and causes redundant map lookups. Instead write out a list of unique
symbol references and have symbols refer to each other using indexes into this
list.
Credit to Michael Hudson-Doyle for kicking this off.
Reduces pkg/linux_amd64 size by 30% from 61MB to 43MB
name old s/op new s/op delta
LinkCmdGo 0.74 ± 3% 0.63 ± 4% -15.22% (p=0.000 n=20+20)
LinkJuju 6.38 ± 6% 5.73 ± 6% -10.16% (p=0.000 n=20+19)
Change-Id: I7e101a0c80b8e673a3ba688295e6f80ea04e1cfb
Reviewed-on: https://go-review.googlesource.com/20099
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Every go executable has COFF symbol table appended at the end. The table is
used by nm and addr2line and contains all symbols present in the executable.
The table is quite large. For example, my go.exe has 11736 records.
To generate symbol table:
1) we walk "all symbols" list to count symbols we want for the table;
2) we allocate large global array of COFFSym structs (32 bytes each)
to fit our symbols;
3) we walk "all symbols" list again to fill our array with contents;
4) we iterate over our global array to write all records to the file.
This CL changes all these steps with single step:
- walk "all symbols" list and write each COFF symbol table record to
the file as we go.
I hope new version is faster and uses less garbage, but I don't know
how to benchmark this.
Change-Id: Ie4870583250131ea4428e0e83a0696c9df1794e0
Reviewed-on: https://go-review.googlesource.com/20580
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
In addition to reflect.Value.Call, exported methods can be invoked
by the Func value in the reflect.Method struct. This CL has the
compiler track what functions get access to a legitimate reflect.Method
struct by looking for interface calls to either of:
Method(int) reflect.Method
MethodByName(string) (reflect.Method, bool)
This is a little overly conservative. If a user implements a type
with one of these methods without using the underlying calls on
reflect.Type, the linker will assume the worst and include all
exported methods. But it's cheap.
No change to any of the binary sizes reported in cl/20483.
For #14740
Change-Id: Ie17786395d0453ce0384d8b240ecb043b7726137
Reviewed-on: https://go-review.googlesource.com/20489
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Today the linker keeps all methods of reachable types. This is
necessary if a program uses reflect.Value.Call. But while use of
reflection is widespread in Go for encoders and decoders, using
it to call a method is rare.
This CL looks for the use of reflect.Value.Call in a program, and
if it is absent, adopts a (reasonably conservative) method pruning
strategy as part of dead code elimination. Any method that is
directly called is kept, and any method that matches a used
interface's method signature is kept.
Whether or not a method body is kept is determined by the relocation
from its receiver's *rtype to its *rtype. A small change in the
compiler marks these relocations as R_METHOD so they can be easily
collected and manipulated by the linker.
As a bonus, this technique removes the text segment of methods that
have been inlined. Looking at the output of building cmd/objdump with
-ldflags=-v=2 shows that inlined methods like
runtime.(*traceAllocBlockPtr).ptr are removed from the program.
Relatively little work is necessary to do this. Linking two
examples, jujud and cmd/objdump show no more than +2% link time.
Binaries that do not use reflect.Call.Value drop 4 - 20% in size:
addr2line: -793KB (18%)
asm: -346KB (8%)
cgo: -490KB (10%)
compile: -564KB (4%)
dist: -736KB (17%)
fix: -404KB (12%)
link: -328KB (7%)
nm: -827KB (19%)
objdump: -712KB (16%)
pack: -327KB (14%)
yacc: -350KB (10%)
Binaries that do use reflect.Call.Value see a modest size decrease
of 2 - 6% thanks to pruning of unexported methods:
api: -151KB (3%)
cover: -222KB (4%)
doc: -106KB (2.5%)
pprof: -314KB (3%)
trace: -357KB (4%)
vet: -187KB (2.7%)
jujud: -4.4MB (5.8%)
cmd/go: -384KB (3.4%)
The trivial Hello example program goes from 2MB to 1.68MB:
package main
import "fmt"
func main() {
fmt.Println("Hello, 世界")
}
Method pruning also helps when building small binaries with
"-ldflags=-s -w". The above program goes from 1.43MB to 1.2MB.
Unfortunately the linker can only tell if reflect.Value.Call has been
statically linked, not if it is dynamically used. And while use is
rare, it is linked into a very common standard library package,
text/template. The result is programs like cmd/go, which don't use
reflect.Value.Call, see limited benefit from this CL. If binary size
is important enough it may be possible to address this in future work.
For #6853.
Change-Id: Iabe90e210e813b08c3f8fd605f841f0458973396
Reviewed-on: https://go-review.googlesource.com/20483
Reviewed-by: Russ Cox <rsc@golang.org>
Alternative to golang.org/cl/19852. This memory layout doesn't have
an easy type representation, but it is noticeably smaller than the
current funcType, and saves significant extra space.
Some notes on the layout are in reflect/type.go:
// A *rtype for each in and out parameter is stored in an array that
// directly follows the funcType (and possibly its uncommonType). So
// a function type with one method, one input, and one output is:
//
// struct {
// funcType
// uncommonType
// [2]*rtype // [0] is in, [1] is out
// uncommonTypeSliceContents
// }
There are three arbitrary limits introduced by this CL:
1. No more than 65535 function input parameters.
2. No more than 32767 function output parameters.
3. reflect.FuncOf is limited to 128 parameters.
I don't think these are limits in practice, but are worth noting.
Reduces godoc binary size by 2.4%, 330KB.
For #6853.
Change-Id: I225c0a0516ebdbe92d41dfdf43f716da42dfe347
Reviewed-on: https://go-review.googlesource.com/19916
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Instead of a pointer on every rtype, use a bit flag to indicate that
the contents of uncommonType directly follows the rtype value when it
is needed.
This requires a bit of juggling in the compiler's rtype encoder. The
backing arrays for fields in the rtype are presently encoded directly
after the slice header. This packing requires separating the encoding
of the uncommonType slice headers from their backing arrays.
Reduces binary size of godoc by ~180KB (1.5%).
No measurable change in all.bash time.
For #6853.
Change-Id: I60205948ceb5c0abba76fdf619652da9c465a597
Reviewed-on: https://go-review.googlesource.com/19790
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Deleting the string merging pass makes the linker 30-35% faster
but makes jujud (using the github.com/davecheney/benchjuju snapshot) 2.5% larger.
Two optimizations bring the space overhead down to 0.6%.
First, change the default alignment for string data to 1 byte.
(It was previously defaulting to larger amounts, usually pointer width.)
Second, write out the type string for T (usually a bigger expression) as "*T"[1:],
so that the type strings for T and *T share storage.
Combined, these obtain the bulk of the benefit of string merging
at essentially no cost. The remaining benefit from string merging
is not worth the excessive cost, so delete it.
As penance for making the jujud binary 0.6% larger,
the next CL in this sequence trims the reflect functype
information enough to make the jujud binary overall 0.75% smaller
(that is, that CL has a net -1.35% effect).
For #6853.
Fixes#14648.
Change-Id: I3fdd74c85410930c36bb66160ca4174ed540fc6e
Reviewed-on: https://go-review.googlesource.com/20334
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
The existing implementation deals with absolute relocations in __TEXT
for darwin/amd64 in build-mode c-shared, but it ignores c-archive.
This results in issues when trying to use a c-archive in an iOS
app on the 64-bit simulator. This patch adds c-archive to the
handling of this issue.
Fixes#14217
Change-Id: I2e4d5193caa531171ad22fd0cd420a8bfb4646a6
Reviewed-on: https://go-review.googlesource.com/19206
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
They were only used for rtype.ptrToThis which David Crawshaw removed a couple
of weeks ago. Removes two traversals of Ctxt.Allsym from the linker but it
doesn't seem to make much difference to performance.
Change-Id: I5c305e0180186f643221d57822d301de4aa18827
Reviewed-on: https://go-review.googlesource.com/20287
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When the linker was written in C, command line arguments were passed
around as null-terminated byte arrays which encouraged checking
characters one at a time. In Go, that can easily lead to
out-of-bounds panics.
Use the more idiomatic strings.HasPrefix when checking cmd/link's -B
argument to avoid the panic, and replace the manual hex decode with
use of the encoding/hex package.
Fixes#14636
Change-Id: I45f765bbd8cf796fee1a9a3496178bf76b117827
Reviewed-on: https://go-review.googlesource.com/20211
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Many read-only strings in Go binaries are substrings of other read-only
strings. A common source is the text form of type information, which
will include both "struct { X int }" and "*struct { X int }" or
"*bytes.Reader" and "func(*bytes.Reader)" in the same binary.
Because this character data is referred to by separate string headers,
we can skip writing the smaller string and modify the pointer
relocation to point to the larger string. This CL does this
deduplication in the linker after the reachable set of strings has
been determined.
This removes 765KB from juju (1.4% without DWARF).
Link time goes at tip goes form 4.6s to 6.3s, but note that this CL
is part of a series that recently reduced link time from 9.6s.
For #6853.
Change-Id: Ib2087cf627c9f1e9a1181f9b4c8f81d1a3f42191
Reviewed-on: https://go-review.googlesource.com/19987
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Minalign > 1 implies that relocations inserted by the linker cannot
target arbitrary bytes.
Related to #14604
Change-Id: Ie68d14887bc4047d9b29b0cb1149a8d14b6c62e2
Reviewed-on: https://go-review.googlesource.com/20214
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL introduces a mergestrings pass after the reachability
analysis to combine all reachable go.string."..." character data
symbols into a single symbol.
Shrinks juju by 1.2mb (1.5%).
Shrinks cmd/go by 0.5% when building without DWARF.
No noticable effect on linker speed.
Change-Id: I2ba3e60bf418f65766bda257f6ca9eea26d895b6
Reviewed-on: https://go-review.googlesource.com/20165
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The new Minalign field sets the minimum alignment for all symbols.
This is required for the upcoming s390x port which requires symbols
be 2-byte aligned for efficient relative addressing.
All preexisting architectures have Minalign set to 1 which means
that this commit should have no effect.
I tested values of 2, 4 and 8 on linux amd64 and the tests appear to
pass. Increasing Minalign to 16 appears to break the runtime. I
think this is due to assumptions made about the layout of module
data.
toolstash -cmp on linux amd64 shows no changes due to this commit.
Resolves#14604
Change-Id: I0fe042d52c4e4732eba5fabcd0c31102a2408764
Reviewed-on: https://go-review.googlesource.com/20149
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
No performance improvement, but possibly more readable.
Linking juju:
tip: real 0m5.470s user 0m6.131s
this: real 0m5.392s user 0m6.087s
Change-Id: I578e94fbe6c11b19d79034c33b3db31d9689d439
Reviewed-on: https://go-review.googlesource.com/20108
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
All callers already had strings. No need to generate byte slice copies
to work on bytes.
Performance not measured, but probably helps at least a bit.
Change-Id: Iec3230b69724fac68caae7aad46f2ce1504e82e5
Reviewed-on: https://go-review.googlesource.com/20136
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Looks a tiny bit faster, which is a surprise. Probably noise.
Motivation is making the LSym structure a little easier to understand.
Linking juju, best of 10:
before: real 0m4.811s user 0m5.582s
after: real 0m4.611s user 0m5.267s
Change-Id: Idbedaf4a6e6e199036a1bbb6760e98c94ed2c282
Reviewed-on: https://go-review.googlesource.com/20142
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also stop creating a map for each symbol, as it does not seem to help.
Linking juju:
tip: real 0m5.470s user 0m6.131s
this: real 0m4.811s user 0m5.582s
Change-Id: Ib3d931c996396a00942581770ff32df1eb8d6615
Reviewed-on: https://go-review.googlesource.com/20140
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It looks like the compiler still uses the Cfunc flag for functions
marked as //go:systemstack, but if I'm reading this right, that
doesn't apply here and the linker no longer needs Cfunc.
Change-Id: I63b9192c2f52f41401263c29dc8dfd8be8a901a1
Reviewed-on: https://go-review.googlesource.com/20105
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This per-symbol table was written with the strategy:
1. record offset and write fake header
2. write body
3. seek back to fake header
4. write real header
This CL collects the per-symbol body into a []byte, then writes the
real header followed by the body to the output file. This saves two
seeks per-symbol and overwriting the fake header.
Small performance improvement (3.5%) in best-of-ten links of godoc:
tip: real 0m1.132s user 0m1.256s
this: real 0m1.090s user 0m1.210s
I'm not sure if the performance measured here alone justifies it,
but I think this is an easier to read style of code.
Change-Id: I1663901eb7c2ee330591b8b6550cdff0402ed5dc
Reviewed-on: https://go-review.googlesource.com/20074
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Used by DWARF writer changes in a followup CL.
Change-Id: I6ec40dcfeaba909d9b8f6cf2603bc5b85c1fa873
Reviewed-on: https://go-review.googlesource.com/20073
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In best of 10, linking cmd/go shows a ~10% improvement.
tip: real 0m1.152s user 0m1.005s
this: real 0m1.065s user 0m0.924s
Change-Id: I303a20b94332feaedc1033c453247a0e4c05c843
Reviewed-on: https://go-review.googlesource.com/19978
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The object file reader in cmd/link reads the symbol name into a scratch
[]byte, converts it to a string, and then does a substring replacement.
Instead, this CL does the replacement on the []byte into the scratch
space and then creates the final string.
Linking godoc without DWARF, best of ten, shows a ~10% improvement.
tip: real 0m1.099s user 0m1.541s
this: real 0m0.990s user 0m1.280s
This is part of an attempt to make suffixarray string deduping
come out as a wash, but it's not there yet:
cl/19987: real 0m1.335s user 0m1.794s
cl/19987+this: real 0m1.225s user 0m1.540s
Change-Id: Idf061fdfbd7f08aa3a1f5933d3f111fdd1659210
Reviewed-on: https://go-review.googlesource.com/20025
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The Cpos function is used frequently (at least once per symbol) and
it is implemented with the seek syscall. Instead, track current
output offset and use it.
Building the godoc binary with DWARF, best of ten:
tip: real 0m1.287s user 0m1.573s
this: real 0m1.208s user 0m1.555s
Change-Id: I068148695cd6b4d32cd145db25e59e6f6bae6945
Reviewed-on: https://go-review.googlesource.com/20055
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reduces number of memory allocations by 12%:
Before: 1816664
After: 1581591
Small speed improvement.
Change-Id: I61281fb852e8e31851a350e3ae756676705024a4
Reviewed-on: https://go-review.googlesource.com/20027
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Preallocate ~2MB for Lsym map (size calculation from http://play.golang.org/p/9L7F5naXRr).
Reduces best of 10 link time of cmd/go by ~4%.
On cmd/go max resident size unaffected, on println hello world max resident size grows by 4mb from 18mb->22mb. Performance improves in both cases.
tip: real 0m1.283s user 0m1.502s sys 0m0.144s
this: real 0m1.341s user 0m1.598s sys 0m0.136s
Change-Id: I4a95e45fe552f1f64f53e868421b9f45a34f8b96
Reviewed-on: https://go-review.googlesource.com/19979
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The Go toolchain stopped creating them before Go 1.3, so no point in
worrying about them today.
History:
- Git commit 250a091 added cmd/ar, which wrote Plan 9 __.SYMDEF
entries into archive files.
- golang.org/cl/6500117 renamed __.SYMDEF to __.GOSYMDEF. (Notably,
the commit message suggests users need to use Go nm to read symbols,
but even back then the toolchain did nothing with __.(GO)?SYMDEF files
except skip over them.)
- golang.org/cl/42880043 added the -pack flag to cmd/gc to directly
produce archives by the Go compiler, and did not write __.GOSYMDEF
entries.
- golang.org/cl/52310044 rewrote cmd/pack in Go, and removed support
for producing __.GOSYMDEF entries.
Change-Id: I255edf40d0d3690e3447e488039fcdef73c6d6b1
Reviewed-on: https://go-review.googlesource.com/19924
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Simplifies some code as ptrToThis was unreliable under dynamic
linking. Now the same type lookup is used regardless of execution
mode.
A synthetic relocation, R_USETYPE, is introduced to make sure the
linker includes *T on use of T, if *T is carrying methods.
Changes the heap dump format. Anything reading the format needs to
look at the last bool of a type of an interface value to determine
if the type should be the pointer-to type.
Reduces binary size of cmd/go by 0.2%.
For #6853.
Change-Id: I79fcb19a97402bdb0193f3c7f6d94ddf061ee7b2
Reviewed-on: https://go-review.googlesource.com/19695
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The Go 1.6 release notes say we'll remove the “-X name value” form
(in favor of the “-X name=value” form) in Go 1.7.
Do that.
Also establish the doc/go1.7.txt file.
Change-Id: Ie4565a6bc5dbcf155181754d8d92bfbb23c75338
Reviewed-on: https://go-review.googlesource.com/19614
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This call to os.Getwd (or getwd) has been part of the linker since the C
implementation in 7d507dc6e6. It stopped being used in 26438d4d80, and
survived the conversion to Go in 1f9dbb60ef.
Its return value goes unused (the linker gets the value for AT_comp_dir in
dwarf.go), remove it.
Change-Id: I3d4594813bb4ee0a6af31a36e19d99ec4b863677
Reviewed-on: https://go-review.googlesource.com/19655
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Add the following flags when supported by the compiler:
-gno-record-gcc-switches
-fdebug-prefix-map=$WORK=/tmp/go-build
Add an empty NAME symbol to the ELF .symtab. GNU ld will add a NAME
symbol when one is not present; including one of our own prevents it
from adding a reference to the link tempdir.
Fixes#13247 for compilers that support -fdebug-prefix-map. (gcc, clang
in the near future.)
Change-Id: I221c71fc59cd23ee8c99bcc038793ff4623c9ffc
Reviewed-on: https://go-review.googlesource.com/19363
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
Fields in Plan 9 object headers are big-endian, on all architectures.
Change-Id: If95ad29750b776338178d660646568bf26a4abda
Reviewed-on: https://go-review.googlesource.com/18964
Reviewed-by: Russ Cox <rsc@golang.org>
