This is a change improving consistency in the source tree.
The pattern foo &= ^bar, was only used six times in src/ directory.
The usage of the supported &^ (bit clear / AND NOT) operator is way more
common, about factor 10x.
Change-Id: If26a2994fd81d23d42189bee00245eb84e672cf3
Reviewed-on: https://go-review.googlesource.com/21224
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
See #14874
This change tells the linker to collect all the itablink symbols and
collect them so that moduledata can have a slice of all compiler
generated itabs.
The logic is shamelessly adapted from what is done with typelink symbols.
Change-Id: Ie93b59acf0fcba908a876d506afbf796f222dbac
Reviewed-on: https://go-review.googlesource.com/20889
Reviewed-by: Keith Randall <khr@golang.org>
Calling the read only Linkrlookup will now not cause the name
string to escape. So a lookup can be performed on a []byte
casted to a string without allocating. This will help a followup
cl and it is also much simpler and cleaner.
Performance not impacted by this.
name old s/op new s/op delta
LinkCmdGo 0.51 ± 6% 0.51 ± 5% ~ (p=0.192 n=98+98)
Change-Id: I7846ba3160eb845a3a29cbf0be703c47369ece16
Reviewed-on: https://go-review.googlesource.com/21187
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Create a byte encoding designed for static Go names.
It is intended to be a compact representation of a name
and optional tag data that can be turned into a Go string
without allocating, and describes whether or not it is
exported without unicode table.
The encoding is described in reflect/type.go:
// The first byte is a bit field containing:
//
// 1<<0 the name is exported
// 1<<1 tag data follows the name
// 1<<2 pkgPath *string follow the name and tag
//
// The next two bytes are the data length:
//
// l := uint16(data[1])<<8 | uint16(data[2])
//
// Bytes [3:3+l] are the string data.
//
// If tag data follows then bytes 3+l and 3+l+1 are the tag length,
// with the data following.
//
// If the import path follows, then ptrSize bytes at the end of
// the data form a *string. The import path is only set for concrete
// methods that are defined in a different package than their type.
Shrinks binary sizes:
cmd/go: 164KB (1.6%)
jujud: 1.0MB (1.5%)
For #6853.
Change-Id: I46b6591015b17936a443c9efb5009de8dfe8b609
Reviewed-on: https://go-review.googlesource.com/20968
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Remove reflect type information for unexported methods that do not
satisfy any interface in the program.
Ideally the unexported method would not appear in the method list at
all, but that is tricky because the slice is built by the compiler.
Reduces binary size:
cmd/go: 81KB (0.8%)
jujud: 258KB (0.4%)
For #6853.
Change-Id: I25ef8df6907e9ac03b18689d584ea46e7d773043
Reviewed-on: https://go-review.googlesource.com/21033
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
It was just a funny way of saying len(Ctxt.Allsym) by now.
Change-Id: Iff75e73c9f7ec4ba26cfef479bbd05d7dcd172f5
Reviewed-on: https://go-review.googlesource.com/20973
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Nothing cares about it.
I did this after looking at the memprof output, but it helps performance a bit:
name old s/op new s/op delta
LinkCmdGo 0.44 ± 3% 0.43 ± 3% -2.20% (p=0.000 n=94+90)
LinkJuju 3.98 ± 5% 3.94 ± 5% -1.19% (p=0.000 n=100+91)
As well as MaxRSS (i.e. what /usr/bin/time -f '%M' prints):
name old MaxRSS new MaxRSS delta
LinkCmdGo 130k ± 0% 120k ± 3% -7.79% (p=0.000 n=79+90)
LinkJuju 862k ± 6% 827k ± 8% -4.01% (p=0.000 n=100+99)
Change-Id: I6306b7b3369576a688659e2ecdb0815b4152ae96
Reviewed-on: https://go-review.googlesource.com/20972
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Debugasm can never be set in cmd/link, so delete it and the code it enables.
Change-Id: If828db0b09f1a9e512dc660ac2750657a769094c
Reviewed-on: https://go-review.googlesource.com/20971
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This expression in readsym:
dup != nil && len(dup.P) > 0 && strings.HasPrefix(s.Name, "gclocals·")
can never be true: if dup != nil, then s.Name is ".dup" (and this is not new:
the same broken logic is present in 1.4, at least). Delete the whole block.
Change-Id: I33b14d9a82b292116d6fd79d22b38e3842501317
Reviewed-on: https://go-review.googlesource.com/20970
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Another object file change, gives a reasonable improvement:
name old s/op new s/op delta
LinkCmdGo 0.46 ± 3% 0.44 ± 9% -3.34% (p=0.000 n=98+82)
LinkJuju 4.09 ± 4% 3.92 ± 5% -4.30% (p=0.000 n=98+99)
I guess the data section could be mmap-ed instead of read, I haven't tried
that.
Change-Id: I959eee470a05526ab1579e3f5d3ede41c16c954f
Reviewed-on: https://go-review.googlesource.com/20928
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reduces size of archives in pkg/linux_amd64 by 3% from 41.5MB to 40.2MB
Change-Id: Id64ca7995de8dd84c9e7ce1985730927cf4bfd66
Reviewed-on: https://go-review.googlesource.com/20912
Reviewed-by: David Crawshaw <crawshaw@golang.org>
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>
People who want to use -buildmode=c-archive in unusual cross-compilation
setups will need something like this. It could also be done via (yet
another) environment variable but I use -extar by analogy with the
existing -extld.
Change-Id: I354cfabc4c470603affd13cd946997b3a24c0e6c
Reviewed-on: https://go-review.googlesource.com/18913
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
https://golang.org/s/execmodes defines rules for how multiple codes of a go
package work when they end up in the address space of a single process, but
currently the linker blows up in this situation. Fix that by loading all .a
files before any .so files and ignoring duplicate symbols found when loading
shared libraries.
I know this is very very late for 1.6 but at least it should clearly not have
any effect when shared libraries are not in use.
Change-Id: I512ac912937e7502ff58eb5628b658ecce3c38e5
Reviewed-on: https://go-review.googlesource.com/18714
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
The linker already applies the fix for elf32, so this just extends it to elf64.
Inspired by https://github.com/pwaller/goupxFixes#13974
Change-Id: I65d92b5be9590657060a0e8e80ff5b86ba40017f
Reviewed-on: https://go-review.googlesource.com/18690
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This makes lldb willing to debug them.
The minimum version is hard-coded at OS X 10.7,
because that is the minimum that Go requires.
For more control over the version, users can
use linkmode=external and pass the relevant flags to the host linker.
Fixes#12941.
Change-Id: I20027be8aa034d07dd2a3326828f75170afe905f
Reviewed-on: https://go-review.googlesource.com/18588
Reviewed-by: Ian Lance Taylor <iant@golang.org>
* Enable c-shared buildmode on darwin/386
* dyld does not support text relocation on i386. Add -read_only_relocs suppress flag to linker
Fixes#13904
Change-Id: I9adbd20d3f36ce9bbccf1bffb746b391780d088f
Reviewed-on: https://go-review.googlesource.com/18500
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
On Windows, externalthreadhandler currently sets the assumed stack
size for the profiler thread and the ctrlhandler threads to 8KB. The
actual stack size is determined by the SizeOfStackReserve field in the
binary set by the linker, which is currently at least 64KB (and
typically 128KB).
It turns out the profiler thread is running within a few words of the
8KB-(stack guard) bound set by externalthreadhandler. If it overflows
this bound, morestack crashes unceremoniously with an access
violation, which we then fail to handle, causing the whole process to
exit without explanation.
To avoid this problem and give us some breathing room, increase the
assumed stack size in externalthreadhandler to 32KB (there's some
unknown amount of stack already in use, so it's not safe to increase
this all the way to the reserve size).
We also document the relationships between externalthreadhandler and
SizeOfStackReserve to make this more obvious in the future.
Change-Id: I2f9f9c0892076d78e09827022ff0f2bedd9680a9
Reviewed-on: https://go-review.googlesource.com/18304
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
This CL changes the source file information in the
standard library's .a files to say "$GOROOT/src/runtime/chan.go"
(with a literal "$GOROOT") instead of spelling out the actual directory.
The linker then substitutes the actual $GOROOT (or $GOROOT_FINAL)
as appropriate.
If people download a binary distribution to an alternate location,
following the instructions at https://golang.org/doc/install#install,
the code before this CL would end up with source paths pointing to
/usr/local/go no matter where the actual sources were.
Now the source paths for built binaries will point to the actual sources
(hopefully).
The source line information in distributed binaries is not affected:
those will still say /usr/local/go. But binaries people build themselves
(their own programs, not the go distribution programs) will be correct.
Fixing this path also fixes the lookup of the runtime-gdb.py file.
Fixes#5533.
Change-Id: I03729baae3fbd8cd636e016275ee5ad2606e4663
Reviewed-on: https://go-review.googlesource.com/18200
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The test for non-package main top-level inputs is done while parsing
the export data. Issue #13468 happened because we were not parsing
the export data when using compiler-generated archives
(that is, when using go tool compile -pack).
Fix this by parsing the export data even for archives.
However, that turns up a different problem: the export data check
reports (one assumes spurious) skew errors now, because it has
not been run since Go 1.2.
(Go 1.3 was the first release to use go tool compile -pack.)
Since the code hasn't run since Go 1.2, it can't be that important.
Since it doesn't work today, just delete it.
Figuring out how to make this code work with Robert's export
format was one of the largest remaining TODOs for that format.
Now we don't have to.
Fixes#13468 and makes the world a better place.
Change-Id: I40a4b284cf140d49d48b714bd80762d6889acdb9
Reviewed-on: https://go-review.googlesource.com/17976
Reviewed-by: Robert Griesemer <gri@golang.org>
Try to remove the most visible artefacts resulting from the
C to Go translation. It includes:
- refactoring the find function to eliminate goto and variable declarations
- removing useless variables still having a _ = xxx
- decreasing the number of upfront variable declarations
No semantic changes.
Change-Id: I84d981c48b2d9e22e6b9db5f2a703c80c60249ba
Reviewed-on: https://go-review.googlesource.com/15681
Reviewed-by: Russ Cox <rsc@golang.org>
This relocation is found in libgcc.a in the .eh_frame, and therefore
needs to be handled when doing an internal link.
Fixes#13375.
Change-Id: Idd9e8178e08851a101b43261a30939bcfaf394f9
Reviewed-on: https://go-review.googlesource.com/17173
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
All the heavy lifting was done by Michael Hudson-Doyle.
Change-Id: I176f15581055078854c2ad9a5807c4dcf0f8d8c5
Reviewed-on: https://go-review.googlesource.com/17074
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Does not fix#12327 but nicer anyway.
Change-Id: I4ad730a4ca833d76957b7571895b3a08a6a530d4
Reviewed-on: https://go-review.googlesource.com/16964
Reviewed-by: Ian Lance Taylor <iant@golang.org>
An internal link may need the C compiler support library, libgcc.a. Add
a -libgcc option to set the name of the compiler support library. If
-libgcc is not used, run the compiler to find it. Permit -libgcc=none
to skip using libgcc at all and hope for the best.
Change cmd/dist to not copy libgcc into the distribution. Add tests to
ensure that all the standard packages that use cgo can be linked in
internal mode without using libgcc. This ensures that somebody with a
Go installation without a C compiler can build programs.
Change-Id: I8ba35fb87ab0dd20e5cc0166b5f4145b04ce52a4
Reviewed-on: https://go-review.googlesource.com/16993
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
This includes the first parts of the general approach to PIC: load PC into CX
whenever it is needed. This is going to lead to large binaries and poor
performance but it's a start and easy to get right.
Change-Id: Ic8bf1d0a74284cca0d94a68cf75024e8ab063b4e
Reviewed-on: https://go-review.googlesource.com/16383
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Change the linker to use a copy of the C compiler support library,
libgcc.a, when doing internal linking. This will be used to satisfy any
undefined symbols referenced by host objects.
Change the dist tool to copy the support library into a new directory
tree under GOROOT/pkg/libgcc. This ensures that libgcc is available
even when building Go programs on a system that has no C compiler. The
C compiler is required when building the Go installation in the first
place, but is not required thereafter.
Change the go tool to not link libgcc into cgo objects.
Correct the linker handling of a weak symbol in an ELF input object to
not always create a new symbol, but to use an existing symbol if there
is one; this is necessary on freebsd-amd64, where libgcc contains a weak
definition of compilerrt_abort_impl.
Fixes#9510.
Change-Id: I1ab28182263238d9bcaf6a42804e5da2a87d8778
Reviewed-on: https://go-review.googlesource.com/16741
Reviewed-by: Russ Cox <rsc@golang.org>
This requires changing the tls access code to match the patterns documented in
the ABI documentation or the system linker will "optimize" it into ridiculousness.
With this change, -buildmode=pie works, although as it is tested in testshared,
the tests are not run yet.
Change-Id: I1efa6687af0a5b8db3385b10f6542a49056b2eb3
Reviewed-on: https://go-review.googlesource.com/15971
Reviewed-by: Russ Cox <rsc@golang.org>
The PowerPC ISA does not have a PC-relative load instruction, which poses
obvious challenges when generating position-independent code. The way the ELFv2
ABI addresses this is to specify that r2 points to a per "module" (shared
library or executable) TOC pointer. Maintaining this pointer requires
cooperation between codegen and the system linker:
* Non-leaf functions leave space on the stack at r1+24 to save the TOC pointer.
* A call to a function that *might* have to go via a PLT stub must be followed
by a nop instruction that the system linker can replace with "ld r1, 24(r1)"
to restore the TOC pointer (only when dynamically linking Go code).
* When calling a function via a function pointer, the address of the function
must be in r12, and the first couple of instructions (the "global entry
point") of the called function use this to derive the address of the TOC
for the module it is in.
* When calling a function that is implemented in the same module, the system
linker adjusts the call to skip over the instructions mentioned above (the
"local entry point"), assuming that r2 is already correctly set.
So this changeset adds the global entry point instructions, sets the metadata so
the system linker knows where the local entry point is, inserts code to save the
TOC pointer at 24(r1), adds a nop after any call not known to be local and copes
with the odd non-local code transfer in the runtime (e.g. the stuff around
jmpdefer). It does not actually compile PIC yet.
Change-Id: I7522e22bdfd2f891745a900c60254fe9e372c854
Reviewed-on: https://go-review.googlesource.com/15967
Reviewed-by: Russ Cox <rsc@golang.org>
The larger stack frames causes the nosplit stack to overflow so the next change
increases the stackguard.
Change-Id: Ib2b4f24f0649eb1d13e3a58d265f13d1b6cc9bf9
Reviewed-on: https://go-review.googlesource.com/15964
Reviewed-by: Russ Cox <rsc@golang.org>
Only internal linking without cgo is supported for now.
Change-Id: Ie6074a8ff3ec13605b72028f2d60758034f87185
Reviewed-on: https://go-review.googlesource.com/14444
Reviewed-by: Minux Ma <minux@golang.org>
The linker writes the number of file symbols (Nhistfile) to the filetab slice
and then Nhistfile offsets -- which means the slice contains Nhistfile+1
entries, not just Nhistfile.
I think this bug has been around since at least 1.4 but it's easier to trigger
with shared libraries and a tiny binary that only has a couple of functions in
it -- try go install -buildmode=shared std && go run -linkshared test/fixedbugs/issue4388.go.
Change-Id: I6c0f01f1e607b9b2b96872e37ffce81281911504
Reviewed-on: https://go-review.googlesource.com/16342
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
They reportedly occur with LLVM 3.7 on FreeBSD ARM.
Fixes#13139.
Change-Id: Ia7d053a8662696b1984e81fbd1d908c951c35a98
Reviewed-on: https://go-review.googlesource.com/16667
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
golang.org/cl/16436 added a local symbol for every global function, but also
added a duplicate entry for the global symbol. Surprisingly this hasn't caused
any noticeable problems, but it's still wrong.
Change-Id: Icd3906760f8aaf7bef31ffd4f2d866d73d36dc2c
Reviewed-on: https://go-review.googlesource.com/16581
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The GNU binutils recently picked up support for new 386/amd64
relocations. Add support for them in the Go linker when doing an
internal link.
The 386 relocation R_386_GOT32X was proposed in
https://groups.google.com/forum/#!topic/ia32-abi/GbJJskkid4I . It can
be treated as identical to the R_386_GOT32 relocation.
The amd64 relocations R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX were
proposed in
https://groups.google.com/forum/#!topic/x86-64-abi/n9AWHogmVY0 . They
can both be treated as identical to the R_X86_64_GOTPCREL relocation.
The purpose of the new relocations is to permit additional linker
relaxations in some cases. We do not attempt to support those cases.
While we're at it, remove the unused and in some cases out of date
_COUNT names from ld/elf.go.
Fixes#13114.
Change-Id: I34ef07f6fcd00cdd2996038ecf46bb77a49e968b
Reviewed-on: https://go-review.googlesource.com/16529
Reviewed-by: Minux Ma <minux@golang.org>
On ppc64x, the thread pointer, held in R13, points 0x7000 bytes past where
thread-local storage begins (presumably to maximize the amount of storage that
can be accessed with a 16-bit signed displacement). The relocations used to
indicate thread-local storage to the platform linker account for this, so to be
able to support external linking we need to change things so the linker applies
this offset instead of the runtime assembly.
Change-Id: I2556c249ab2d802cae62c44b2b4c5b44787d7059
Reviewed-on: https://go-review.googlesource.com/14233
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
And get rid of the stupid game of encoding the instruction in the addend.
Change-Id: Ib4de7515196cbc1e63b4261b01931cf02a44c1e6
Reviewed-on: https://go-review.googlesource.com/14055
Reviewed-by: Russ Cox <rsc@golang.org>
When dynamically linking, we want references to functions defined
in this module to always be to the function object, not to the
PLT. We force this by writing an additional local symbol for
every global function symbol and making all relocations against
the global symbol refer to this local symbol instead. This is
approximately equivalent to the ELF linker -Bsymbolic-functions
option, but that is buggy on several platforms.
Change-Id: Ie6983eb4d1947f8543736fd349f9a90df3cce91a
Reviewed-on: https://go-review.googlesource.com/16436
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Android linker does not handle TLS for us. We set up the TLS slot
for g, as darwin/386,amd64 handle instead. This is disgusting and
fragile. We will eventually fix this ugly hack by taking advantage
of the recent TLS IE model implementation. (Instead of referencing
an GOT entry, make the code sequence look into the TLS variable that
holds the offset.)
The TLS slot for g in android/amd64 assumes a fixed offset from %fs.
See runtime/cgo/gcc_android_amd64.c for details.
For golang/go#10743
Change-Id: I1a3fc207946c665515f79026a56ea19134ede2dd
Reviewed-on: https://go-review.googlesource.com/15991
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Depends on external linking right now. I have no immediate use for
this, but wanted to check how hard it is to support as android/amd64
is coming and it will require PIE.
Change-Id: I65c6b19159f40db4c79cf312cd0368c2b2527bfd
Reviewed-on: https://go-review.googlesource.com/16072
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Preparation for dealing with binary export format. Accept $$B
as marker for export data. For now, skip that data if found.
Change-Id: I464ba22aaedcf349725379d91070fc900d93b7a2
Reviewed-on: https://go-review.googlesource.com/16222
Reviewed-by: Chris Manghane <cmang@golang.org>
The -msan option causes the linker to link against the runtime/msan
package in order to use the C/C++ memory sanitizer.
This CL passes tests but is not usable by itself. The actual
runtime/msan package, and support for -msan in the go tool and the
compiler, and tests, are in separate CLs.
Change-Id: I02c097393b98c5b80e40ee3dbc167a8b4d23efe0
Reviewed-on: https://go-review.googlesource.com/16161
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Instead of open-coding conversions from *string to unsafe.Pointer then
to *stringStruct, add a helper function to add some type safety.
Bonus: This caught two **string values being converted to
*stringStruct in heapdump.go.
While here, get rid of the redundant _string type, but add in a
stringStructDWARF type used for generating DWARF debug info.
Change-Id: I8882f8cca66ac45190270f82019a5d85db023bd2
Reviewed-on: https://go-review.googlesource.com/16131
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Shared libraries on ppc64le will require a larger minimum stack frame (because
the ABI mandates that the TOC pointer is available at 24(R1)). Part 2b of
preparing for that is to have all the code in the linker that needs to know
this size of this call a function to find out.
Change-Id: I246363840096db22e44beabbe38b61d60c1f31ad
Reviewed-on: https://go-review.googlesource.com/15675
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For #10807
Change-Id: Ied826d06cb622edf6413b6f2cdcc46987ab0b05a
Reviewed-on: https://go-review.googlesource.com/16054
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Go cannot allow lazy PLT resolution when calling between Go functions because
the lazy resolution can use more stack than is available. Lazy resolution is
disabled by passing -z now to the system linker, but unfortunately was only
passed when linking to a Go shared library. That sounds fine, but the shared
library containing the runtime is not linked to any other Go shared library but
calls main.init and main.main via a PLT, and before this fix this did use lazy
resolution. (For some reason this never caused a problem on intel, but it
breaks on ppc64le). Fortunately the fix is very simple: always pass -z now to
the system linker when dynamically linking Go.
Change-Id: I7806d40aac80dcd1e56b95864d1cfeb1c42614e2
Reviewed-on: https://go-review.googlesource.com/15870
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The -W option has not worked since Go 1.3. It is not documented. When
it did work, it generated useful output, but it was for human viewing;
there was no reason to write a script that passes the -W option, so it's
unlikely that anybody is using it today.
Change-Id: I4769f1ffd308a48324a866592eb7fd79a4cdee54
Reviewed-on: https://go-review.googlesource.com/15701
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Go shared libraries do not support dlclose, and there is no likelihood
that they will suppose dlclose in the future. Set the DF_1_NODELETE
flag to tell the dynamic linker to not attempt to remove them from
memory. This makes the shared library act as though every call to
dlopen passed the RTLD_NODELETE flag.
Fixes#12582.
Update #11100.
Update #12873.
Change-Id: Id4b6e90a1b54e2e6fc8355b5fb22c5978fc762b4
Reviewed-on: https://go-review.googlesource.com/15605
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
It's particularly nice to get rid of the android special cases in the linker.
Change-Id: I516363af7ce8a6b2f196fe49cb8887ac787a6dad
Reviewed-on: https://go-review.googlesource.com/14197
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It is generally expected that the ELF flags of a dynamically linked executable
and the libraries it links against match. Go's linker currently always produces
executables with flags that do not declare a float abi (hard, soft) at all, but
when cgo is involved it is unlikely that this matches the system libraries
being linked against -- really the decision about ABI is made by the C compiler
during the invocation of cgo.
This change is basically a port of the code from binutils that parses the
".ARM.attributes" section to check for the tag that declares that the code is
built for the hard-float ABI.
Fixes#7094
Change-Id: I737c8f3b5ed4af545cfc3e86722d03eb83083402
Reviewed-on: https://go-review.googlesource.com/14860
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Only one use of stringsCompare is left. Cannot simply be replaced by
strings.Compare for bootstrapping reasons I guess.
Moving the function away from util.go to the actual destination data.go
also would not help much. So I left this one unchanged for readability and convenience.
Change-Id: I60d22fec0be8f8c47c80586436f9a550af59194e
Reviewed-on: https://go-review.googlesource.com/14953
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Not sure how I managed to do this, or get it past review.
Change-Id: I141b97ef8e09dcc9c910c45493a584a3dced2b28
Reviewed-on: https://go-review.googlesource.com/14634
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
this leaves lots of cruft behind, will delete that soon
Change-Id: I12d6b6192f89bcdd89b2b0873774bd3458373b8a
Reviewed-on: https://go-review.googlesource.com/14196
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Also run testcshared.
Fixes#12425
Change-Id: I5baea8d772d3462f945aab96260b4197dbb20c0a
Reviewed-on: https://go-review.googlesource.com/14143
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
The change in genasmsym to add STYPELINK to the switch should fix things on
darwin/arm64.
Fixes#10914
Updates #9210
Change-Id: Iab4a6678dd04cec6114e683caac5cf31b1063309
Reviewed-on: https://go-review.googlesource.com/14306
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestNoteReading fails on Solaris with linkmode=external due to some
assumptions made about how ELF .note sections are written by some
linkers.
On current versions of Solaris and older derivatives, SHF_ALLOC is
intentionally ignored for .note sections unless the .note section is
assigned to the text segment via a mapfile. Also, if .note sections
are assigned to the text segment, no PT_NOTE program header will be
created thwarting Go's attempts at attempting to quickly find the
.note.
Furthermore, Go assumes that the relevant note segment will be placed
early in the file while the Solaris linker currently places the note
segment last in the file, additionally thwarting Go's optimisation
attempts that read only the first 16KB of the file to find the
buildid.
The fix is to detect when the note section is outside of the first
16KB of the file and then fallback to additionally reading that
section of the file. This way, in future versions of Solaris when
this linking behaviour is changed, the fast path will always succeed
and we'll only be slower if it fails; likewise, any other linker that
does this will also just work.
Fixes#12178
Change-Id: I61c1dc3f744ae3ad63938386d2ace8a432c0efe1
Reviewed-on: https://go-review.googlesource.com/14210
Run-TryBot: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
This reverts commit 2c2cbb69c8.
Broke darwin/arm64
Change-Id: Ibd2dea475d6ce6a8b4b40e2da19a83fc0514025d
Reviewed-on: https://go-review.googlesource.com/14301
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Some symbols, for example, masks requires 16-byte alignment, and
they are placed in the text section. Before this change, the text
section is only aligned to 4-byte, and it's making masks unaligned.
Fixes#12415.
Change-Id: I7767778d1b4f7d3e74c2719a02848350782a4160
Reviewed-on: https://go-review.googlesource.com/14166
Run-TryBot: Minux Ma <minux@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
Fixes#10914
Updates #9210
Change-Id: I7178daadc0ae87953d5a084aa3d580f4e3b46d47
Reviewed-on: https://go-review.googlesource.com/10300
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
And do it properly so freebsd and nacl still work.
Change-Id: I6f9f30e93ceae6dee59215ed608c6a158bdbdbb0
Reviewed-on: https://go-review.googlesource.com/14280
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also simplifies some silliness around making the .tbss section wrt internal
vs external linking. The "make TLS make sense" project has quite a few more
steps to go.
Issue #11270
Change-Id: Ia4fa135cb22d916728ead95bdbc0ebc1ae06f05c
Reviewed-on: https://go-review.googlesource.com/13990
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
And clean up the mess on arm64 (the mess on arm is too confusing).
See issue #10050
Change-Id: I2ce813fe8646d4e818eb660612a7e4b2bb04de4c
Reviewed-on: https://go-review.googlesource.com/13884
Reviewed-by: Ian Lance Taylor <iant@golang.org>
No longer used after previous hashmap change.
Change-Id: I558470f872281e84a78406132df4e391d077b833
Reviewed-on: https://go-review.googlesource.com/13785
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This was always a bit confusing, but it also fixes a problem: runtime.firstmoduledata
was always overridden in the linker to be a local symbol but cmd/internal/obj had
already rewritten code accessing it to access it via the GOT. This works on amd64, but
causes link failures on other platforms (e.g. arm64).
Change-Id: I9b8153af74b4d0f092211d63a000d15818f39773
Reviewed-on: https://go-review.googlesource.com/13786
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The nosplit stack overflow checks were confused about morestack.
The comment about not having correct SP information at the call
to morestack was true, but that was a real bug, not something to
work around. I fixed that problem in CL 12144. With that fixed,
no need to special-case morestack in the way done here.
This cleanup and simplification of the code was the first step
to fixing a bug that happened when I started working on the
arm64 frame size adjustments, but the cleanup was sufficient
to make the bug go away.
For #9880.
Change-Id: I16b69a5c16b6b8cb4090295d3029c42d606e3b9b
Reviewed-on: https://go-review.googlesource.com/12846
Reviewed-by: Austin Clements <austin@google.com>
On Windows, gcc -o foo will generate foo.exe. Prevent that from
happening by adding a final '.' if necessary so that GCC thinks that
the file already has an extension.
Also remove the initial output file when doing an external link, and
use mayberemoveoutfile, not os.Remove, when building an archive
(otherwise we will do the wrong thing for -buildmode=c-archive -o
/dev/null).
I didn't add a test, as it requires using cgo and -o on Windows.
Fixes#11725.
Change-Id: I6ea12437bb6b4b9b8ee5c3b52d83509fa2437b2d
Reviewed-on: https://go-review.googlesource.com/12243
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Same as we do for string symbols.
Fixes#11583.
Change-Id: Ia9264f6faf486697d987051b7f9851d37d8ad381
Reviewed-on: https://go-review.googlesource.com/12531
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The one in misc/makerelease/makerelease.go is particularly bad and
probably warrants rotating our keys.
I didn't update old weekly notes, and reverted some changes involving
test code for now, since we're late in the Go 1.5 freeze. Otherwise,
the rest are all auto-generated changes, and all manually reviewed.
Change-Id: Ia2753576ab5d64826a167d259f48a2f50508792d
Reviewed-on: https://go-review.googlesource.com/12048
Reviewed-by: Rob Pike <r@golang.org>
Instead of silently truncating integers to their expected range, check
that they're within range and emit errors if not. Intended to help
narrow down the cause of issue #11617.
Change-Id: Ia7b577270f8438ca7479262702371e26277f1ea7
Reviewed-on: https://go-review.googlesource.com/12050
Reviewed-by: Ian Lance Taylor <iant@golang.org>
We can't address more than this on amd64 anyway.
Fixes#9862.
Change-Id: Ifb1abae558e2e1ee2dc953a76995f3f08c60b1df
Reviewed-on: https://go-review.googlesource.com/11715
Reviewed-by: Austin Clements <austin@google.com>
This code used to only be run for ELF, with the predictable
result that using -s with external linking broke on Windows and OS X.
Moving it here should fix Windows and does fix OS X.
CL 10835 also claims to fix the crash on Windows.
I don't know whether it does so correctly, but regardless,
this CL should make that one a no-op.
Fixes#10254.
Change-Id: I2e7b45ab0c28568ddbb1b50581dcc157ae0e7ffe
Reviewed-on: https://go-review.googlesource.com/11695
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The old code was recording the current table output offset,
so the table from the next function would be used instead of
the runtime realizing that there was no table at all.
Add debug constant in runtime to check this for every function
at startup. It's too expensive to do that by default, but we can
do the last five functions. The end of the table is usually where
the C symbols end up, so that's where the problems typically are.
Fixes#10747.
Fixes#11396.
Change-Id: I13592e78017969fc22979fa902e19e1b151d41b1
Reviewed-on: https://go-review.googlesource.com/11657
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
It looks like the test for whether symbols contain subsymbols is wrong.
In particular, symbols in C libraries are mistakenly considered container
symbols.
Fix the test so only symbols which actually have a subsymbol
are excluded from the symtab. When linking cgo programs the list
of containers is small, something like:
container _/home/khr/sandbox/symtab/misc/cgo/test(.text)<74>
container _/home/khr/sandbox/symtab/misc/cgo/test/issue8828(.text)<75>
container _/home/khr/sandbox/symtab/misc/cgo/test/issue9026(.text)<76>
container runtime/cgo(.text)<77>
I'm not sure this is the right fix. In particular I can't reproduce
the original problem. Anyone have a repro they can try and see if
this fix works?
Fixes#10747Fixes#11396
Change-Id: Id8b016389d33348b4a791fdcba0f9db8ae71ebf3
Reviewed-on: https://go-review.googlesource.com/11652
Reviewed-by: Russ Cox <rsc@golang.org>
Partial revert of cl/10284 to get -buildmode=c-archive working for
darwin/arm.
Manually tested with iostest.bash while builder is offline.
Change-Id: I98e4e209765666e320e680e11151fce59e2afde9
Reviewed-on: https://go-review.googlesource.com/11306
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
All of the heavy-lifting was done by minux@, with his external-linking support
for darwin/arm64: golang.org/cl/8781
Change-Id: I7c9fbc19246f418c065c92fb2c13c00026ff0f82
Reviewed-on: https://go-review.googlesource.com/11127
Run-TryBot: Srdjan Petrovic <spetrovic@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This makes the behaviour match what happens when duplicate symbols are read
from regular object files and fixes errors about cgoAlwaysFalse when linking
an executable that uses cgo against a shared library.
Change-Id: Ibb8cd8fe3f7813cde504b7483f1e857868d7e063
Reviewed-on: https://go-review.googlesource.com/11117
Reviewed-by: Ian Lance Taylor <iant@golang.org>
These were found by grepping the comments from the go code and feeding
the output to aspell.
Change-Id: Id734d6c8d1938ec3c36bd94a4dbbad577e3ad395
Reviewed-on: https://go-review.googlesource.com/10941
Reviewed-by: Aamir Khan <syst3m.w0rm@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Change-Id: If11621985c0a5a1f2133cdc974f37fd944b93e5e
Reviewed-on: https://go-review.googlesource.com/10808
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also fix the interaction between -buildmode and -shared.
It's okay for -shared to change the default build mode,
but it's not okay for it to silently override an explicit -buildmode=exe.
Change-Id: Id40f93d140cddf75b19e262b3ba4856ee09a07ba
Reviewed-on: https://go-review.googlesource.com/10315
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
People invoking the linker directly already have to change their scripts
to use the new "go tool link", so this is a good time to make the -X flag
behave like all other Go flags and take just a single argument.
The old syntax will continue to be accepted (it is rewritten into the new
syntax before flag parsing). Maybe some day we will be able to retire it.
Even if we never retire the old syntax, having the new syntax at least
makes the rewriting much less of a kludge.
Change-Id: I91e8df94f4c22b2186e81d7f1016b8767d777eac
Reviewed-on: https://go-review.googlesource.com/10310
Reviewed-by: Rob Pike <r@golang.org>
These are the Go 1.4 docs but refreshed for Go 1.5.
The most sigificant change is that all references to the Plan 9 toolchain are gone.
The tools no longer bear any meaningful resemblance.
Change-Id: I44f5cadb832a982323d7fee0b77673e55d761b35
Reviewed-on: https://go-review.googlesource.com/10298
Reviewed-by: Rob Pike <r@golang.org>
Non-ELF binary formats are much less flexible and typically do not
have a good place to store the build ID.
We store it as raw bytes at the beginning of the text segment.
The only system I know of that will be upset about this is NaCl,
and NaCl is an ELF system and does not use this.
For #11048.
Change-Id: Iaa7ace703c4cf36392e752eea9b55e2ce49e9826
Reviewed-on: https://go-review.googlesource.com/10708
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Other binary formats to follow.
Using our own note instead of the GNU build ID note because
we are not the GNU project, and I can't guarantee that the semantics
of our note and the semantics of the GNU note will match forever.
(Also they don't match today.)
For #11048.
Change-Id: Iec7e5a2e49d52b6d3a51b0aface2de7c77a45491
Reviewed-on: https://go-review.googlesource.com/10706
Reviewed-by: Ian Lance Taylor <iant@golang.org>
stkcheck is flow-insensitive: It processes calls in PC order.
Since morestack was always the first call in a function,
it was a safe, conservative approximation to simply adjust stack
space as we went, recognizing morestack when it showed up.
Subsequent CLS will rearrange the function prologue;
morestack may no longer be the first call in a function.
Introducing flow-sensitivity to stkcheck would allow this,
and possibly allow a smaller stackguard.
It is also a high risk change and possibly expensive.
Instead, assume that all calls to morestack occur as
part of the function prologue, no matter where they
are located in the program text.
Updates #10587.
Change-Id: I4dcdd4256a980fc4bc433a68a10989ff57f7034f
Reviewed-on: https://go-review.googlesource.com/10496
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We already read the address of a gcmask/gcprog out of the type data, but I
didn't know how many bytes to read. But it turns out that it's easy to
calculate, so change to do that. This means that we no longer depend on the
local symbols being present, allowing me to strip the shared libraries for
distribution and make them a lot smaller.
As a bonus, this makes LSym another 24 bytes smaller, down to 296 bytes now.
Change-Id: I379d359e28d63afae6753efd23efdf1fbb716992
Reviewed-on: https://go-review.googlesource.com/10377
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The motivation for this is the innocuous looking test case that is added. This
creates a stack exe -> libdep2.so -> libdep.so -> libruntime.so. The problem
comes from the fact that a function from libdep.so gets inlined all the way
into exe. This (unsurprisingly) means that the object file for exe references
symbols from libdep.so, which means that -ldep needs to be passed when linking
exe and it isn't. The fix is simply to pass it -- there is no harm in passing
it when it's not needed.
The thing is, it's not clear at all in the current code to see how the linker
can know that libdep2 is linked against libdep. It could look through the
DT_NEEDED entries in libdep2 and try to guess which are Go libraries, but it
feels better to be explicit. So this adds another SHT_NOTE section that lists
the shared libraries a shared library was linked against, and makes sure the
complete set of depended upon shared libraries is passed to the external
linker.
Change-Id: I79aa6f98b4db4721d657a7eb7b7f062269bf49e2
Reviewed-on: https://go-review.googlesource.com/10376
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This makes for a more stable API for tools (including cmd/link itself) to
extract the abi hash from a shared library and makes it possible at all for a
library that has had the local symbol table removed.
The existing note-writing code only supports writing notes into the very start
of the object file so they are easy to find in core dumps. This doesn't apply
to the "go" notes and means that all notes have to fit into a fixed size
budget. That's annoying now we have more notes (and the next CL will add
another one) so this does a little bit of work to make adding notes that do not
have to go at the start of the file easier and moves the writing of the package
list note over to that mechanism, which lets me revert a hack that increased
the size budget mentioned above for -buildmode=shared builds.
Change-Id: I6077a68d395c8a2bc43dec8506e73c71ef77d9b9
Reviewed-on: https://go-review.googlesource.com/10375
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The LSym.Section and Section.Elfsect fields were defined as interface{} but
always had the same concrete type (*Section and *ElfShdr respectively) so just
define them with that type. Reduces size of LSym from 328 to 320 bytes and
reduces best-of-10 maxresident size from 246028k to 238036k when linking
libstd.so.
Change-Id: Ie7112c53e4c2c7ce5fe233b81372aa5633f572e8
Reviewed-on: https://go-review.googlesource.com/10410
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
At some point this code should probably move to cmd/link/internal/ld,
but at least for now just handle c-archive like c-shared.
Change-Id: Ic17656529cb0fe189a37f15e670350ab13bb5276
Reviewed-on: https://go-review.googlesource.com/10385
Reviewed-by: Andrew Gerrand <adg@golang.org>
It can be useful when debugging to be able to see what the external
linker is doing even when it succeeds. In particular this permits
passing -v to the external linker to see precisely what it is doing.
Change-Id: Ifed441912d97bbebea20303fdb899e140b380215
Reviewed-on: https://go-review.googlesource.com/10363
Reviewed-by: Minux Ma <minux@golang.org>
This CL removes the remaining visible uses of the "architecture letter" concept.
(They are no longer in tool names nor in source directory names.)
Because the architecture letter concept is now gone, delete GOCHAR
from "go env" output, and change go/build.ArchChar to return an
error always.
The architecture letter is still used in the compiler and linker sources
as a clumsy architecture enumeration, but that use is not visible to
Go users and can be cleaned up separately.
Change-Id: I4d97a38f372003fb610c9c5241bea440d9dbeb8d
Reviewed-on: https://go-review.googlesource.com/10289
Reviewed-by: Rob Pike <r@golang.org>
Trivial merging of 5g, 6g, ... into go tool compile,
and similarlly 5l, 6l, ... into go tool link.
The files compile/main.go and link/main.go are new.
Everything else in those directories is a move followed by
change of imports and package name.
This CL breaks the build. Manual fixups are in the next CL.
See golang-dev thread titled "go tool compile, etc" for background.
Change-Id: Id35ff5a5859ad9037c61275d637b1bd51df6828b
Reviewed-on: https://go-review.googlesource.com/10287
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Rob Pike <r@golang.org>
In preparation for making the current linker cmd/link.
If cmd/newlink is ever completed, it can be moved back.
See golang-dev thread titled "go tool compile, etc" for background.
Change-Id: I4029580f470038240c5181a37ea4202ba971f9ef
Reviewed-on: https://go-review.googlesource.com/10286
Reviewed-by: Rob Pike <r@golang.org>
The constants in cmd/internal/goobj had gone stale (we had three copies of
these constants, working on reducing that was what got me to noticing this).
Some of the changes to link.hello.darwin.amd64 are the change from absolute
to %rip-relative addressing, a change which happened quite a while ago...
Depends on http://golang.org/cl/9113.
Fixes#10501.
Change-Id: Iaa1511f458a32228c2df2ccd0076bb9ae212a035
Reviewed-on: https://go-review.googlesource.com/9105
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
debug/goobj is not ready to be published but it is
needed for the various binary-reading commands.
Move to cmd/internal/goobj.
(The Go 1.3 release branch deleted it, but that's not
an option anymore due to the command dependencies.
The API is still not vetted nor terribly well designed.)
LGTM=adg, dsymonds
R=adg, dsymonds
CC=golang-codereviews
https://golang.org/cl/174250043
The file is used by assembly code to define symbols like NOSPLIT.
Having it hidden inside the cmd directory makes it hard to access
outside the standard repository.
Solution: As with a couple of other files used by cgo, copy the
file into the pkg directory and add a -I argument to the assembler
to access it. Thus one can write just
#include "textflag.h"
in .s files.
The names in runtime are not updated because in the boot sequence the
file has not been copied yet when runtime is built. All other .s files
in the repository are updated.
Changes to doc/asm.html, src/cmd/dist/build.c, and src/cmd/go/build.go
are hand-made. The rest are just the renaming done by a global
substitution. (Yay sam).
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/128050043
The >>1 shift needs to happen before converting to int32, otherwise
large values will decode with an incorrect sign bit.
The <<31 shift can happen before or after, but before is consistent
with liblink and the go12symtab doc.
Bug demo at http://play.golang.org/p/jLrhPUakIu
LGTM=rsc
R=golang-codereviews, minux, rsc
CC=golang-codereviews
https://golang.org/cl/119630043
The new code is adapted from the Go 1.2 nosplit code,
but it does not have the bug reported in issue 7623:
g% go run nosplit.go
g% go1.2 run nosplit.go
BUG
rejected incorrectly:
main 0 call f; f 120
linker output:
# _/tmp/go-test-nosplit021064539
main.main: nosplit stack overflow
120 guaranteed after split check in main.main
112 on entry to main.f
-8 after main.f uses 120
g%
Fixes#6931.
Fixes#7623.
LGTM=iant
R=golang-codereviews, iant, ality
CC=golang-codereviews, r
https://golang.org/cl/88190043
Without the leaf bit, the linker cannot record
the correct frame size in the symbol table, and
then stack traces get mangled. (Only for ARM.)
Fixes#7338.
Fixes#7347.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/88550043
The relocation and automatic variable types were using
arch-specific numbers. Introduce portable enumerations
instead.
To the best of my knowledge, these are the only arch-specific
bits left in the new object file format.
Remove now, before Go 1.3, because file formats are forever.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/87670044
There are changes we know we want to make, but not before Go 1.3
Add a version number so that we can make them more easily later.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/87670043
The code was returning the original value rather than the cloned value
resulting in the tests not being repeatable.
Fixes#7111.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/65720045
The golden file for link.hello.darwin.amd64
was a little ahead of the checked-in code.
R=iant
TBR=iant
CC=golang-codereviews
https://golang.org/cl/51870043
Related changes included in this CL:
- Add explicit start symbol to Prog.
- Add omitRuntime bool to Prog.
- Introduce p.Packages[""] to hold automatic symbols
- Add SymOrder to Prog to preserve symbol order.
- Add layout test (and fix bug that was putting everything in text section).
R=iant
CC=golang-codereviews
https://golang.org/cl/51260045
The hex dumps will diff better, and I hope they will avoid
a repeat of http://bugs.debian.org/716853.
The CL will probably show the testdata diffs as "binary",
but in fact the binary versions are being replaced by
textual hex dumps (output of hexdump -C).
R=iant
CC=golang-codereviews
https://golang.org/cl/51000044
