If the final pass(es) are identical during ssa.html generation,
they are persisted in-memory as "pendingPhases" but never get
written as a column in the html. This change flushes those
in-memory phases.
Fixes#38242
Change-Id: Id13477dcbe7b419a818bb457861b2422ba5ef4bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/227182
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Replace HTMLWriter's Logger field with a *Func. Implement Fatalf method
for HTMLWriter which gets the Frontend() from the Func and calls down
into it's Fatalf method, passing the msg and args along. Replace
remaining calls to the old Logger with calls to logging methods on
the Func.
Change-Id: I966342ef9997396f3416fb152fa52d60080ebecb
Reviewed-on: https://go-review.googlesource.com/c/go/+/227277
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 201783 enable -d=checkptr when -race or -msan is specified
everywhere but windows.
But, now that all unsafe pointer conversions in the standard
library are fixed, enable -d=checkptr even on windows.
Updates #34964
Updates #34972
Change-Id: Id912fa83b0d5b46c6f1c134c742fd94d2d185835
Reviewed-on: https://go-review.googlesource.com/c/go/+/227003
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This only removes the ability to build it, and removes it as a
src/buildall.bash target (which uses go tool dist list).
Now:
$ go tool dist list | grep ^darwin
darwin/amd64
darwin/arm64
After this, remaining is removing leftover port--specific code in the
tree.
Updates #37610
Updates #37611
Change-Id: I00f03b2355c2e152f75e57abd3063be243529d2d
Reviewed-on: https://go-review.googlesource.com/c/go/+/226985
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Before using some CPU instructions, we must check for their presence.
We use global variables in the runtime package to record features.
Prior to this CL, we issued a regular memory load for these features.
The downside to this is that, because it is a regular memory load,
it cannot be hoisted out of loops or otherwise reordered with other loads.
This CL introduces a new intrinsic just for checking cpu features.
It still ends up resulting in a memory load, but that memory load can
now be floated to the entry block and rematerialized as needed.
One downside is that the regular load could be combined with the comparison
into a CMPBconstload+NE. This new intrinsic cannot; it generates MOVB+TESTB+NE.
(It is possible that MOVBQZX+TESTQ+NE would be better.)
This CL does only amd64. It is easy to extend to other architectures.
For the benchmark in #36196, on my machine, this offers a mild speedup.
name old time/op new time/op delta
FMA-8 1.39ns ± 6% 1.29ns ± 9% -7.19% (p=0.000 n=97+96)
NonFMA-8 2.03ns ±11% 2.04ns ±12% ~ (p=0.618 n=99+98)
Updates #15808
Updates #36196
Change-Id: I75e2fcfcf5a6df1bdb80657a7143bed69fca6deb
Reviewed-on: https://go-review.googlesource.com/c/go/+/212360
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
We still disallow inlining for an immediately-recursive function, but allow
inlining if a function is in a recursion chain.
If all functions in the recursion chain are simple, then we could inline
forever down the recursion chain (eventually running out of stack on the
compiler), so we add a map to keep track of the functions we have
already inlined at a call site. We stop inlining when we reach a
function that we have already inlined in the recursive chain. Of course,
normally the inlining will have stopped earlier, because of the cost
function.
We could also limit the depth of inlining by a simple count (say, limit
max inlining of 10 at any given site). Would that limit other
opportunities too much?
Added a test in test/inline.go. runtime.BenchmarkStackCopyNoCache() is
also already a good test that triggers the check to stop inlining
when we reach the start of the recursive chain again.
For the bent benchmark suite, the performance improvement was mostly not
statistically significant, but the geomean averaged out to: -0.68%. The text size
increase was less than .1% for all bent benchmarks. The cmd/go text size increase
was 0.02% and the cmd/compile text size increase was .1%.
Fixes#29737
Change-Id: I892fa84bb07a947b3125ec8f25ed0e508bf2bdf5
Reviewed-on: https://go-review.googlesource.com/c/go/+/226818
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
CL 221427 added TestExitCode. This test is failing
on Plan 9 because ExitCode is always equal to 1
on error since Plan 9 use error strings.
This change fixes TestExitCode by checking that
ExitCode is equal to 1 on error instead of the
specific value.
Fixes#38237.
Change-Id: Ie269722e731e275e5bfc51644c1fa6be76525f1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/227158
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
MVS reports an error when a go.mod file declares a module path that
doesn't match the path it was required with. If the module is a
replacement, its declared path may be the original path (preferred) or
the replacement path.
This CL makes the reported error a little more clear: the "required as"
path should be the original required path, not the replacement path.
Fixes#38220
Change-Id: I08b50a100679a447c8803cca1d1b32bc115ec1b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/227097
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Windows requires checking with the .exe extension.
Change-Id: I8e2fe83df81b92f04967bafb28f8effde999f597
Reviewed-on: https://go-review.googlesource.com/c/go/+/227157
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
For 1.15, unless someone really wants it in 1.14.
A performance-sensitive user thought this would be useful,
though "large" was not well-defined. If 128 is large,
there are 139 static instances of "large" copies in the compiler
itself.
Includes test.
Change-Id: I81f20c62da59d37072429f3a22c1809e6fb2946d
Reviewed-on: https://go-review.googlesource.com/c/go/+/205066
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Loading arguments of Xchg(64) and Xadd(64) functions to registers
could be done only once.
Change-Id: Iaf0a695ec9c6a221dfa755855edb68c476978a5b
Reviewed-on: https://go-review.googlesource.com/c/go/+/227001
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In stack bound check pass, check a call once, not over and over
again. Fix an accidental quadratic behavior...
In particular, switching to the new linker caused MIPS builders
noticeably slower. This CL fixes it.
Change-Id: Idd00c79e80af6278652c92a1d9d7bb2d194e9490
Reviewed-on: https://go-review.googlesource.com/c/go/+/227078
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Generate a CALLIND relocation only for indirect calls, not for
indirect jumps. In particular, the RET instruction is lowered to
JMP (LR), an indirect jump, and occurs frequently. The large
amount of spurious relocations causes the linker to do a lot of
extra work.
Change-Id: Ie0edc04609788f5a687fd00c22558c3f83867697
Reviewed-on: https://go-review.googlesource.com/c/go/+/227079
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
In TestMMap, write to temporary directory, instead of the current
directory (which may not be writeable).
Fix linux-mips64le-mengzhuo builder.
Change-Id: I06dc3266f125523568c543634079c447d91903bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/227077
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
flag treats -h or -help as a special case to print a nice help
message, but exit with a status code of 2. This update makes
that status code 0.
Fixes#37533
Change-Id: I7e0bd29944ce46607fb7cfc6740734f7444a151a
GitHub-Last-Rev: 83f64d757b
GitHub-Pull-Request: golang/go#37530
Reviewed-on: https://go-review.googlesource.com/c/go/+/221427
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Update race detector syso files for some platforms.
There's still 2 more to do, but they might take a while so I'm
mailing the ones I have now.
Note: some arm64 tests did not complete successfully due to out
of memory errors, but I suspect the .syso is correct.
Update #14481
Update #37485 (I think?)
Update #37355
Change-Id: I7e7e707a1fd7574855a538ba89dc11acc999c760
Reviewed-on: https://go-review.googlesource.com/c/go/+/226981
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When the request context was canceled, the Transport.RoundTrip method
could return before the fetch promise resolved. This would cause the
success and failure callback functions to get called after they've
been released, which in turn prints a "call to released function"
error to the console.
Avoid that problem by releasing the callbacks after the fetch promise
completes, by moving the release calls into the callbacks themselves.
This way we can still return from the Transport.RoundTrip method as
soon as the context is canceled, without waiting on the promise to
resolve. If the AbortController is unavailable and it's not possible to
abort the fetch operation, the promise may take a long time to resolve.
For #38003.
Change-Id: Ied1475e31dcba101b3326521b0cd653dbb345e1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/226204
Reviewed-by: Johan Brandhorst <johan.brandhorst@gmail.com>
Reviewed-by: Richard Musiol <neelance@gmail.com>
In the dev.link branch we continued developing the new object
file format support and the linker improvements described in
https://golang.org/s/better-linker .
The new object file is index-based and provides random access.
The linker maps the object files into read-only memory, and
accesses symbols on-demand using indices, as opposed to reading
all object files sequentially into the heap with the old format.
This work is not done yet. Currently we still convert back to the
old in-memory representation half way through the link process,
but only for symbols that are needed.
At this point, we think it is ready to enable the new object
files and new linker for early testing. Using the new object
files and the new linker, it reduces the linker's memory usage by
~10% and wall-clock run time by ~5%, and more to come.
Currently, both the old and new object file formats are supported.
The new format and new linker are used by default. For feature
gating, as a fallback, the old format and old linker can be used
by setting the compiler/assembler/linker's -go115newobj flag to
false. Note that the flag needs to be specified consistently to
all compilations, i.e.
-gcflags=all=-go115newobj=false -asmflags=all=-go115newobj=false -ldflags=all=-go115newobj=false
In case we need to revert, we can set the flags default to false.
CL 224626 is an example.
cmd/oldlink is a full copy of the old linker. It is invoked if
the old format is requested.
This is a clean merge, as we already merged master branch to
dev.link first.
Change-Id: I8f081eef8c4621362f03ecbcb850d6262b5d3dc6
Update the old linker to bring in recent changes made on the
master branch: CL 225397 and CL 220917.
This brings cmd/oldlink to be in sync with commit
aa4d92b8aa.
Change-Id: Ic386736fa30944dcb71c57096915381d3e6be82c
Reviewed-on: https://go-review.googlesource.com/c/go/+/227028
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The only conflict is a modify-deletion conflict in
cmd/link/internal/ld/link.go, where the old error reporter is
deleted in the new linker. Ported to
cmd/link/internal/ld/errors.go.
Change-Id: I5c78f398ea95bc1d7e6579c84dd8252c9f2196b7
Cleaned up for readability and consistency.
There is one tiny behavioral change: when PSSSaltLengthEqualsHash is
used and both hash and opts.Hash were set, hash.Size() was used for the
salt length instead of opts.Hash.Size(). That's clearly wrong because
opts.Hash is documented to override hash.
Change-Id: I3e25dad933961eac827c6d2e3bbfe45fc5a6fb0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/226937
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
This ports CL 226997 to the dev.link branch.
- The assembler part and old object file writing are unchanged.
- Changes to cmd/link are applied to cmd/oldlink.
- Add alignment field to new object files for the new linker.
Change-Id: Id00f323ae5bdd86b2709a702ee28bcaa9ba962f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/227025
Reviewed-by: Than McIntosh <thanm@google.com>
ErrorUnresolved attempts to find the missing symbol in another ABI,
in order to provide more friendly error messages. However, in doing so
it checks the same ABI and can find the symbol reference for the symbol
that it is currently reporting the unresolved error for. Avoid this by
ignoring SXREF symbols, which is the same behaviour used when linking
is performed.
Fixes#33979
Change-Id: I9bfc40146dec2666d25e93d3bcd1984da5c71215
Reviewed-on: https://go-review.googlesource.com/c/go/+/220917
Run-TryBot: Than McIntosh <thanm@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Recently, the gVisor project needs an instruction's address
with 128 bytes alignment to fit the architecture requirement
for interrupt table.
This patch allows aligning an instruction's address to be
aligned to a specific value (2^n and in the range [8, 2048])
The main changes include:
1. Adds a new element in the FuncInfo structure defined in
cmd/internal/obj/link.go file to record the alignment
information.
2. Adds a new element in the Func structure defined in
cmd/internal/goobj/read.go file to read the alignment
information.
3. Adds the assembler support to align an intruction's offset
with a specific value (2^n and in the range [8, 2048]).
e.g. "PCALIGN $256" indicates that the next instruction should
be aligned to 256 bytes.
4. An instruction's alignment is relative to the start of the
function where this instruction is located, so the function's
address must be aligned to the same or coarser boundary.
This CL also adds a test.
Change-Id: I9b365c111b3a12f767728f1b45aa0c00f073c37d
Reviewed-on: https://go-review.googlesource.com/c/go/+/226997
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Store multiple instructions can clobber flags on s390x when the
offset passed into the assembler is outside the range representable
with a signed 20 bit integer. This is because the assembler uses
the agfi instruction to implement the large offset. The assembler
could use a different sequence of instructions, but for now just
mark the instruction as 'clobberFlags' since this is risk free.
Noticed while investigating #38195.
No test yet since I'm not sure how to get this bug to trigger and
I haven't seen it affect real code.
Change-Id: I4a6ab96455a3ef8ffacb76ef0166b97eb40ff925
Reviewed-on: https://go-review.googlesource.com/c/go/+/226759
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The problem was discovered while running
go test -a -short -gcflags=all=-d=checkptr -run=TestUDPConnSpecificMethods net
WSAMsg is type defined by Windows. And WSAMsg.Name could point to two
different structures for IPv4 and IPV6 sockets.
Currently WSAMsg.Name is declared as *syscall.RawSockaddrAny. But that
violates
(1) Conversion of a *T1 to Pointer to *T2.
rule of
https://golang.org/pkg/unsafe/#Pointer
When we convert *syscall.RawSockaddrInet4 into *syscall.RawSockaddrAny,
syscall.RawSockaddrInet4 and syscall.RawSockaddrAny do not share an
equivalent memory layout.
Same for *syscall.SockaddrInet6 into *syscall.RawSockaddrAny.
This CL changes WSAMsg.Name type to *syscall.Pointer. syscall.Pointer
length is 0, and that at least makes type checker happy.
After this change I was able to run
go test -a -short -gcflags=all=-d=checkptr std cmd
without type checker complaining.
Updates #34972
Change-Id: Ic5c2321c20abd805c687ee16ef6f643a2f8cd93f
Reviewed-on: https://go-review.googlesource.com/c/go/+/222457
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
WSASendto converts unsafe.Pointer to *syscall.RawSockaddrAny. But that
violates every rule of
https://golang.org/pkg/unsafe/#Pointer
Implement WSASendto by calling Windows WSASendTo API by calling
syscall.Syscall9 directly. This allows us to comply with
(4) Conversion of a Pointer to a uintptr when calling syscall.Syscall
rule.
After this change, this commands succeeds:
go test -a -short -gcflags=all=-d=checkptr -run=TestPacketConn net
Updates #34972
Change-Id: Ib9a810bedf9e05251b7d3c7f69e15bfbd177ac62
Reviewed-on: https://go-review.googlesource.com/c/go/+/220544
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It plays way too loose with unsafe.Pointer rules.
It runs afoul of the checkptr rules, so some race detector builds
were failing.
Fixes#38210
Change-Id: I5e1c78201d06295524fdedb3fe5b49d61446f443
Reviewed-on: https://go-review.googlesource.com/c/go/+/226880
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
We can initialize the runtime sigqueue packages on first use.
We don't require an explicit initialization step. So, remove it.
Change-Id: I484e02dc2c67395fd5584f35ecda2e28b37168df
Reviewed-on: https://go-review.googlesource.com/c/go/+/226540
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
DWARF constant symbols were always marked and converted to
sym.Symbols when DWARF generation uses sym.Symbols. Now that the
DWARF generation uses the loader, no need to force-mark them.
Change-Id: Ia4032430697cfa901fb4b6d106a483973277ea0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/226803
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Now that we switched to new style accessors everywhere, remove
the old ones.
Keep goobj2.Sym, Reloc, and Aux for now, as they are still used
on the writer side.
Change-Id: I6f3f0d812ff591ea6f12cd0155232f160d53d453
Reviewed-on: https://go-review.googlesource.com/c/go/+/226802
Reviewed-by: Than McIntosh <thanm@google.com>
They are essentially duplicates of cmd/link tests. No need to
test twice.
Change-Id: I91fdc996f5e160631648ee63341c4e46bb6cc54d
Reviewed-on: https://go-review.googlesource.com/c/go/+/226801
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
The new object file support in the old linker should not be used.
This is a minimal change that removes stuff from the old linker's
loader package, so that it decouples from the goobj2 package,
allowing the latter to evolve.
Keep the change local in the loader package, so most of the old
linker doesn't need to change. At this point I don't think we
want to make significant changes to the old linker.
Change-Id: I078c4cbb35dc4627c4b82f512a4aceec9b594925
Reviewed-on: https://go-review.googlesource.com/c/go/+/226800
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
We already move to new style accessors in the linker. This will
allow us to get rid of the read side of old style ones.
Change-Id: Id0c171c5634a5977fe8a6f764cb0d48203993ab7
Reviewed-on: https://go-review.googlesource.com/c/go/+/226799
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Along the line with Reloc and Aux, use new-style accessors for
the Sym type. They avoid reading unnecessary fields, and also
look nicer (to me).
Change-Id: Ie37c5149a6edb2184724b3dfa26952015e74c085
Reviewed-on: https://go-review.googlesource.com/c/go/+/226798
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Previously, StringRef is encoded as an offset pointing to
{ len, [len]byte }. This CL changes it to { len, offset }, where
offset points the bytes.
With the new format, reading a string header is just reading two
adjacent uint32s, without accessing the string table. This should
improve locality of object file reading.
Change-Id: Iec30708f9d9adb2f0242db6c4767c0f8e730f4df
Reviewed-on: https://go-review.googlesource.com/c/go/+/226797
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Trying this CL again, with a test that skips 387.
When converting from float32->float64->float32, any signal NaNs
get converted to quiet NaNs. Avoid that so using reflect.Value.Convert
between two float32 types keeps the signal bit of NaNs.
Skip the test on 387. I don't see any sane way of ensuring that a
float load + float store is faithful on that platform.
Fixes#36400
Change-Id: Ic316c74ddc155632e40424e207375b5d50dcd853
Reviewed-on: https://go-review.googlesource.com/c/go/+/221792
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
We got the permissions wrong on the mmapped region.
Change-Id: Ica6372fd9d9a787ab20a763e5785fb9fb34ff623
Reviewed-on: https://go-review.googlesource.com/c/go/+/226366
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Make sure we never overrun the end address.
Should fix AIX build.
Change-Id: I9926387d4512ec8b4acc32b7f32cee2b2aca25b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/226718
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Combine columns in ssa.html output if they are identical. There
can now be multiple titles per column which are all clickable to
expand and collapse their column. Give collapsed columns some
padding for better readability. Some of the work in this CL was
started by Josh Bleecher Snyder and mailed to me in order to
continue to completion.
Updates #37766
Change-Id: I313b0917dc1bafe1eb99d91798ea915e5bcfaae9
Reviewed-on: https://go-review.googlesource.com/c/go/+/226209
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
