math/big.Int Cmp method does not have a fast path for the case if x and y are the same.
Fixes#30856
Change-Id: Ia9a5b5f72db9d73af1b13ed6ac39ecff87d10393
Reviewed-on: https://go-review.googlesource.com/c/go/+/178957
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Stack object symbol is named as <FunctionName>.stkobj. If the
function itself is not DUPOK, its stack object symbol should only
be defined in the package where the function is defined,
therefore no duplicates.
If in the future we change the stack object symbol to
content-hash naming, as other gcdata symbols, we can mark it as
DUPOK.
Change-Id: I5aee96578940e2f76e7115d96cd2716021672c03
Reviewed-on: https://go-review.googlesource.com/c/go/+/191437
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The net/url error in question now quotes the URL, so update the expected
output string.
While at it, also update a comment in httputil, though that doesn't
affect any test.
Fixes#33910.
Change-Id: I0981f528b24337c2952ef60c0db3b7ff72d72110
Reviewed-on: https://go-review.googlesource.com/c/go/+/192078
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Current implementation doesn't always make it obvious what the exact
problem with the URL is, so this makes it clearer by consistently quoting
the invalid URL, as is the norm in other parsing implementations, eg.:
strconv.Atoi(" 123") returns an error: parsing " 123": invalid syntax
Updates #29261
Change-Id: Icc6bff8b4a4584677c0f769992823e6e1e0d397d
GitHub-Last-Rev: 648b9d93fe
GitHub-Pull-Request: golang/go#29384
Reviewed-on: https://go-review.googlesource.com/c/go/+/185117
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Per the code review guidelines: "Words in names that are
initialisms or acronyms have a consistent case."
Change-Id: I347b02d2f48455f2cbbc040191ba197e3e8f23fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/191970
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Production profiling shows ~15% of url.Parse time being spend in the overhead
of calling strings.IndexByte through strings.Index instead of calling
strings.IndexByte directly.
name old time/op new time/op delta
Split 15.5ns ± 2% 10.7ns ± 3% -30.98% (p=0.000 n=20+19)
Change-Id: Ie25dd4afa93539a1335a91ab2a4a367f97bd3df0
Reviewed-on: https://go-review.googlesource.com/c/go/+/178877
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
golang.org/cl/143180 changed gc.eqtype to types.Identical, but gc.eqtype
is still mentioned in some comments. Remove them and update comments to
mention new functions instead.
Change-Id: I6c5eece5221f524556ee55db80de0e4bdfaf166e
Reviewed-on: https://go-review.googlesource.com/c/go/+/191357
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Extend the optimization introduced in CL 141118 to the wasm architecture.
And for reference, the rules trigger 212 times while building std and cmd
$GOOS=js GOARCH=wasm gotip build std cmd
$grep -E "Wasm.rules:44(1|2|3|4)" rulelog | wc -l
212
Updates #26498
Change-Id: I153684a2b98589ae812b42268da08b65679e09d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/185477
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Richard Musiol <neelance@gmail.com>
When an invalid URL was passed to DumpRequestOut, it would directly return
without gracefully shutting down the reader goroutine.
So we create a channel and signal the reader goroutine to exit
if an error occurs during roundtrip.
Fixes#32571
Change-Id: I8c2970f1601e599f3d1ebfed298faf5f5716fc2c
Reviewed-on: https://go-review.googlesource.com/c/go/+/182037
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Use the shiftIsBounded function to generate more efficient
Shift instructions.
Updates #25167
Change-Id: Id350f8462dc3a7ed3bfed0bcbea2860b8f40048a
Reviewed-on: https://go-review.googlesource.com/c/go/+/182558
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Richard Musiol <neelance@gmail.com>
This CL optimizes math.bits.TrailingZeros16 on 386 with
a pair of BSFL and ORL instrcutions.
The case TrailingZeros16-4 of the benchmark test in
math/bits shows big improvement.
name old time/op new time/op delta
TrailingZeros16-4 1.55ns ± 1% 0.87ns ± 1% -43.87% (p=0.000 n=50+49)
Change-Id: Ia899975b0e46f45dcd20223b713ed632bc32740b
Reviewed-on: https://go-review.googlesource.com/c/go/+/189277
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This CL add test cases for the unary FP negative
operation.
Change-Id: I54e7292ca9df05da0c2b113adefc97ee1e94c6e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/190937
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This CL performs the branchelim optimization on WASM with its
select instruction. And the total size of pkg/js_wasm decreased
about 80KB by this optimization.
Change-Id: I868eb146120a1cac5c4609c8e9ddb07e4da8a1d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/190957
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Richard Musiol <neelance@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This patch supports the EL0 and EL1 system registers used in MRS/MSR
instructions. This patch refactors the assembler code, allowing the
assembler to read system register information from the automatically
generated sysRegEnc.go file and move existing declared system registers
to the sysRegEnc.go file.
This patch adds 431 system registers, it is worth noting that the number
of special registers is initialized to less than 1024 in the list7.go file.
This CL also adds some test cases to test the newly added system registers.
The test cases are contributed by Dianhong Xu <Dianhong.Xu@arm.com>
Change-Id: Ic09a937eaaeefe82bd08b5dd726808f8ff6cebf6
Reviewed-on: https://go-review.googlesource.com/c/go/+/189577
Reviewed-by: Ben Shi <powerman1st@163.com>
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We never used it, might as well get rid of it.
Change-Id: I5c23c93e90173bff9ac1fc1b8ae1e2025215d6eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/191938
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
SSLv3 has been irreparably broken since the POODLE attack 5 years ago
and RFC 7568 (f.k.a. draft-ietf-tls-sslv3-diediedie) prohibits its use
in no uncertain terms.
As announced in the Go 1.13 release notes, remove support for it
entirely in Go 1.14.
Updates #32716
Change-Id: Id653557961d8f75f484a01e6afd2e104a4ccceaf
Reviewed-on: https://go-review.googlesource.com/c/go/+/191976
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
'git ls-remote' started recognizing the '--' separator at some point
after 2.7.4, but git defaults to version 2.7.4 on Ubuntu 16.04 LTS,
which remains supported by Ubuntu until April 2021.
We added '--' tokens to most VCS commands as a defensive measure in
CL 181237, but it isn't strictly necessary here because the 'scheme'
argument to our template is chosen from a predefined list: we can
safely drop it to retain compatibility.
Fixes#33836
Updates #26746
Change-Id: Ibb53366b95f8029b587e0b7646a439330d759ac7
Reviewed-on: https://go-review.googlesource.com/c/go/+/191978
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
The TestParseErrors test function was not strict with unwanted errors
received from url.Parse(). It was not failing in such cases, now it does
Fixes#33646
Updates #29098
Change-Id: I069521093e2bff8b1fcd41ffd3f9799f3108bc61
GitHub-Last-Rev: e6844c57f9
GitHub-Pull-Request: golang/go#33876
Reviewed-on: https://go-review.googlesource.com/c/go/+/191966
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Because the Node AST represents references to declared objects (e.g.,
variables, packages, types, constants) by directly pointing to the
referred object, we don't have use-position info for these objects.
For switch statements with duplicate cases, we report back where the
first duplicate value appeared. However, due to the AST
representation, if the value was a declared constant, we mistakenly
reported the constant declaration position as the previous case
position.
This CL reports back against the 'case' keyword's position instead, if
there's no more precise information available to us.
It also refactors code to emit the same "previous at" error message
for duplicate values in map literals.
Thanks to Emmanuel Odeke for the test case.
Fixes#33460.
Change-Id: Iec69542ccd4aad594dde8df02d1b880a422c5622
Reviewed-on: https://go-review.googlesource.com/c/go/+/188901
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use efaceOf to safely convert from *interface{} to *_eface, and to
make it clearer what the pointer arithmetic is computing.
Incidentally, remove a spurious unsafe.Pointer->*uint8->unsafe.Pointer
round trip conversion in newproc.
No behavior change.
Change-Id: I2ad9d791d35d8bd008ef43b03dad1589713c5fd4
Reviewed-on: https://go-review.googlesource.com/c/go/+/190457
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
I'm trying to keep the code changes minimal for backporting to Go 1.13,
so it is still possible for a handful of entries to leak,
but the leaks are now O(1) instead of O(N) in the steady state.
Longer-term, I think it would be a good idea to coalesce idleMu with
connsPerHostMu and clear entries out of both queues as soon as their
goroutines are done waiting.
Fixes#33849Fixes#33850
Change-Id: Ia66bc64671eb1014369f2d3a01debfc023b44281
Reviewed-on: https://go-review.googlesource.com/c/go/+/191964
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The assembly output for x & c == c, where c is power of 2:
MOVQ "".set+8(SP), AX
ANDQ $8, AX
CMPQ AX, $8
SETEQ "".~r2+24(SP)
With optimization using bitset:
MOVQ "".set+8(SP), AX
BTL $3, AX
SETCS "".~r2+24(SP)
output less than 1 instruction.
However, there is no speed improvement:
name old time/op new time/op delta
AllBitSet-8 0.35ns ± 0% 0.35ns ± 0% ~ (all equal)
Fixes#31904
Change-Id: I5dca4e410bf45716ed2145e3473979ec997e35d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/175957
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The decoder called this function to check numbers being decoded into a
json.Number. However, these can't be quoted as strings, so the tokenizer
has already verified they are valid JSON numbers.
Verified this by adding a test with such an input. As expected, it
produces a syntax error, not the fmt.Errorf - that line could never
execute.
Since the only remaining non-test caller of isvalidnumber is in
encode.go, move the function there.
This change should slightly reduce the amount of work when decoding into
json.Number, though that isn't very common nor part of any current
benchmarks.
Change-Id: I67a1723deb3d18d5b542d6dd35f3ae56a43f23eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/184817
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
There is an unnecessary lower operation in isJSType.
Simple logic fix can improve tiny performance.
name old time/op new time/op delta
isJSType-8 152ns ± 0% 58ns ± 7% -61.82% (p=0.001 n=6+8)
name old alloc/op new alloc/op delta
isJSType-8 32.0B ± 0% 0.0B -100.00% (p=0.000 n=8+8)
name old allocs/op new allocs/op delta
isJSType-8 1.00 ± 0% 0.00 -100.00% (p=0.000 n=8+8)
Change-Id: I281aadf1677d4377920c9649af206381189a27e6
Reviewed-on: https://go-review.googlesource.com/c/go/+/177118
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
This reverts https://golang.org/cl/185080.
Reason for revert: some new changes are erroring again, so this broke the builders.
Change-Id: I28da16da98b90cefbb47173d31bbbb56e43062d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/191781
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
state and ssafn both have their own Fatalf, so use them instead of
global Fatalf.
Updates #19683
Change-Id: Ie02a961d4285ab0a3f3b8d889a5b498d926ed567
Reviewed-on: https://go-review.googlesource.com/c/go/+/188539
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
First, add cpu and memory profiling flags, as these are useful to see
where rulegen is spending its time. It now takes many seconds to run on
a recent laptop, so we have to keep an eye on what it's doing.
Second, stop writing '_ = var' lines to keep imports and variables used
at all times. Now that rulegen removes all such unused names, they're
unnecessary.
To perform the removal, lean on go/types to first detect what names are
unused. We can configure it to give us all the type-checking errors in a
file, so we can collect all "declared but not used" errors in a single
pass.
We then use astutil.Apply to remove the relevant nodes based on the line
information from each unused error. This allows us to apply the changes
without having to do extra parser+printer roundtrips to plaintext, which
are far too expensive.
We need to do multiple such passes, as removing an unused variable
declaration might then make another declaration unused. Two passes are
enough to clean every file at the moment, so add a limit of three passes
for now to avoid eating cpu uncontrollably by accident.
The resulting performance of the changes above is a ~30% loss across the
table, since go/types is fairly expensive. The numbers were obtained
with 'benchcmd Rulegen go run *.go', which involves compiling rulegen
itself, but that seems reflective of how the program is used.
name old time/op new time/op delta
Rulegen 5.61s ± 0% 7.36s ± 0% +31.17% (p=0.016 n=5+4)
name old user-time/op new user-time/op delta
Rulegen 7.20s ± 1% 9.92s ± 1% +37.76% (p=0.016 n=5+4)
name old sys-time/op new sys-time/op delta
Rulegen 135ms ±19% 169ms ±17% +25.66% (p=0.032 n=5+5)
name old peak-RSS-bytes new peak-RSS-bytes delta
Rulegen 71.0MB ± 2% 85.6MB ± 2% +20.56% (p=0.008 n=5+5)
We can live with a bit more resource usage, but the time/op getting
close to 10s isn't good. To win that back, introduce concurrency in
main.go. This further increases resource usage a bit, but the real time
on this quad-core laptop is greatly reduced. The final benchstat is as
follows:
name old time/op new time/op delta
Rulegen 5.61s ± 0% 3.97s ± 1% -29.26% (p=0.008 n=5+5)
name old user-time/op new user-time/op delta
Rulegen 7.20s ± 1% 13.91s ± 1% +93.09% (p=0.008 n=5+5)
name old sys-time/op new sys-time/op delta
Rulegen 135ms ±19% 269ms ± 9% +99.17% (p=0.008 n=5+5)
name old peak-RSS-bytes new peak-RSS-bytes delta
Rulegen 71.0MB ± 2% 226.3MB ± 1% +218.72% (p=0.008 n=5+5)
It might be possible to reduce the cpu or memory usage in the future,
such as configuring go/types to do less work, or taking shortcuts to
avoid having to run it many times. For now, ~2x cpu and ~4x memory usage
seems like a fair trade for a faster and better rulegen.
Finally, we can remove the old code that tried to remove some unused
variables in a hacky and unmaintainable way.
Change-Id: Iff9e83e3f253babf5a1bd48cc993033b8550cee6
Reviewed-on: https://go-review.googlesource.com/c/go/+/189798
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This removes a special case that was added to fix issue #10956, but that
was never actually effective. The code in the test case still fails to
read, so perhaps the zip64 support added in CL 6463050 inadvertently
caught this particular case.
It's possible that the original theorized bug still exists, but I'm not
convinced it was ever fixed.
Update #28700
Change-Id: I4854de616364510f64a6def30b308686563f8dbb
Reviewed-on: https://go-review.googlesource.com/c/go/+/179757
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Template.New calls t.init, which allocates several items that
are immediately rewritten by copy, so avoid the call to New
Change-Id: I16c7cb001bbcd14cf547c1a2db2734a2f8214e7e
Reviewed-on: https://go-review.googlesource.com/c/go/+/182757
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
The TestParseErrors test function was not strict with unwanted errors
received from url.Parse(). It was not failing in such cases, now it does.
Change-Id: I18a26a68c1136f5c762989a76e04b47e33dd35f1
GitHub-Last-Rev: c33f9842f7
GitHub-Pull-Request: golang/go#32954
Reviewed-on: https://go-review.googlesource.com/c/go/+/185080
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
TransmitFile does not allow for number of bytes that can be
transmitted to be larger than 2147483646. See
https://docs.microsoft.com/en-us/windows/win32/api/mswsock/nf-mswsock-transmitfile
for details. So adjust sendFile accordingly.
No test added, because this would require creating large file
(more than 2GB file).
Fixes#33193.
Change-Id: I82e0cb104d112264e4ea363bb20b6d02ac30b38e
Reviewed-on: https://go-review.googlesource.com/c/go/+/187037
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
After Go.1.10+ strings.Builder is known as more efficient in
concatenating and building strings than bytes.Buffer.
In this CL,
there is a minor logic fix for getting advantage of strings.builder.
name old time/op new time/op delta
DefinedTemplate-8 543ns ± 3% 512ns ± 2% -5.73% (p=0.000 n=8+8)
name old alloc/op new alloc/op delta
DefinedTemplate-8 192B ± 0% 160B ± 0% -16.67% (p=0.000 n=8+8)
name old allocs/op new allocs/op delta
DefinedTemplate-8 5.00 ± 0% 5.00 ± 0% ~ (all equal)
Change-Id: Icda0054d146e6c5e32ed8a4d13221bb6850d31b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/175261
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Add brief descriptions of why one might implement
an Is or As method.
Fixes#33364.
Change-Id: I81a091bf564c654ddb9ef3997e780451a01efb7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/191338
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Because TestUnmarshal actually allocates a new value to decode into
using ptr's pointer type, any existing data is thrown away. This was
harmless in alomst all of the test cases, minus the "overwriting of
data" ones added in 2015 in CL 12209.
I spotted that nothing covered decoding a JSON array with few elements
into a slice which already had many elements. I initially assumed that
the code was buggy or that some code could be removed, when in fact
there simply wasn't any code covering the edge case.
Move those two tests to TestPrefilled, which already served a very
similar purpose. Remove the map case, as TestPrefilled already has
plenty of prefilled map cases. Moreover, we no longer reset an entire
map when decoding, as per the godoc:
To unmarshal a JSON object into a map, Unmarshal first
establishes a map to use. If the map is nil, Unmarshal allocates
a new map. Otherwise Unmarshal reuses the existing map, keeping
existing entries.
Finally, to ensure that ptr is used correctly in the future, make
TestUnmarshal error if it's anything other than a pointer to a zero
value. That is, the only correct use should be new(type). Don't rename
the ptr field, as that would be extremely noisy and cause unwanted merge
conflicts.
Change-Id: I41e3ecfeae42d877ac5443a6bd622ac3d6c8120c
Reviewed-on: https://go-review.googlesource.com/c/go/+/185738
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
rulegen.go produces plaintext Go code directly, which was fine for a
while. However, that's started being a bottleneck for making code
generation more complex, as we can only generate code directly one line
at a time.
Some workarounds were used, like multiple layers of buffers to generate
chunks of code, to then use strings.Contains to see whether variables
need to be defined or not. However, that's error-prone, verbose, and
difficult to work with.
A better approach is to generate an intermediate syntax tree in memory,
which we can inspect and modify easily. For example, we could run a
number of "passes" on the syntax tree before writing to disk, such as
removing unused variables, simplifying logic, or moving declarations
closer to their uses.
This is the first step in that direction, without changing any of the
generated code. We didn't use go/ast directly, as it's too complex for
our needs. In particular, we only need a few kinds of simple statements,
but we do want to support arbitrary expressions. As such, define a
simple set of statement structs, and add thin layers for printer.Fprint
and ast.Inspect.
A nice side effect of this change, besides removing some buffers and
string handling, is that we can now avoid passing so many parameters
around. And, while we add over a hundred lines of code, the tricky
pieces of code are now a bit simpler to follow.
While at it, apply some cleanups, such as replacing isVariable with
token.IsIdentifier, and consistently using log.Fatalf.
Follow-up CLs will start improving the generated code, also simplifying
the rulegen code itself. I've added some TODOs for the low-hanging fruit
that I intend to work on right after.
Updates #30810.
Change-Id: Ic371c192b29c85dfc4a001be7fbcbeec85facc9d
Reviewed-on: https://go-review.googlesource.com/c/go/+/177539
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
