If we call slicebytetostring immediately (with no intervening writes)
before calling map access or delete functions with the resulting
string as the key, then we can just use the ptr/len of the
slicebytetostring argument as the key. This avoids an allocation.
Fixes#44898
Update #71132
There's old code in cmd/compile/internal/walk/order.go that handles
some of these cases.
1. m[string(b)]
2. s := string(b); m[s]
3. m[[2]string{string(b1),string(b2)}]
The old code handled cases 1&3. The new code handles cases 1&2.
We'll leave the old code around to keep 3 working, although it seems
not terribly common.
Case 2 happens particularly after inlining, so it is pretty common.
Change-Id: I8913226ca79d2c65f4e2bd69a38ac8c976a57e43
Reviewed-on: https://go-review.googlesource.com/c/go/+/640656
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
mapiterinit allows external linkname. These users must allocate their
own iter struct for initialization by mapiterinit. Since the type is
unexported, they also must define the struct themselves. As a result,
they of course define the struct matching the old hiter definition (in
map_noswiss.go).
The old definition is smaller on 32-bit platforms. On those platforms,
mapiternext will clobber memory outside of the caller's allocation.
On all platforms, the pointer layout between the old hiter and new
maps.Iter does not match. Thus the GC may miss pointers and free
reachable objects early, or it may see non-pointers that look like heap
pointers and throw due to invalid references to free objects.
To avoid these issues, we must keep mapiterinit and mapiternext with the
old hiter definition. The most straightforward way to do this is to use
mapiterinit and mapiternext as a compatibility layer between the old and
new iter types.
The first step to that is to move normal map use off of these functions,
which is what this CL does.
Introduce new mapIterStart and mapIterNext functions that replace the
former functions everywhere in the toolchain. These have the same
behavior as the old functions.
This CL temporarily makes the old functions throw to ensure we don't
have hidden dependencies on them. We cannot remove them entirely because
GOEXPERIMENT=noswissmap still uses the old names, and internal/goobj
requires all builtins to exist regardless of GOEXPERIMENT. The next CL
will introduce the compatibility layer.
I want to avoid using linkname between runtime and reflect, as that
would also allow external linknames. So mapIterStart and mapIterNext are
duplicated in reflect, which can be done trivially, as it imports
internal/runtime/maps.
For #71408.
Change-Id: I6a6a636c6d4bd1392618c67ca648d3f061afe669
Reviewed-on: https://go-review.googlesource.com/c/go/+/643898
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Re-enable tests for stack-allocated maps and fast map accessors.
Those are implemented now.
Update #54766
Change-Id: I8c019702bd9fb077b2fe3f7c78e8e9e10d2263a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/642376
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Temporary measure to reduce the required MVP code.
For #54766.
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest-swissmap
Change-Id: I44dc8acd0dc8280c6beb40451998e84bc85c238a
Reviewed-on: https://go-review.googlesource.com/c/go/+/580915
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Previously TryBot-tested with bucket bits = 4.
Also tested locally with bucket bits = 5.
This makes it much easier to change the size of map
buckets, and hopefully provides pointers to all the
code that in some way depends on details of map layout.
Change-Id: I9f6669d1eadd02f182d0bc3f959dc5f385fa1683
Reviewed-on: https://go-review.googlesource.com/c/go/+/462115
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Currently we only include static entries in the hint for sizing
the map when allocating a map for a map literal. Change that to
include all entries.
This will be an overallocation if the dynamic entries in the map have
equal keys, but equal keys in map literals are rare, and at worst we
waste a bit of space.
Fixes#43020
Change-Id: I232f82f15316bdf4ea6d657d25a0b094b77884ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/383634
Run-TryBot: Keith Randall <khr@golang.org>
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Some codegen tests were written with the assumption that
arguments and results are in memory, and with a specific stack
layout. With the register ABI, the assumption is no longer true.
Adjust the tests to work with both cases.
- For tests expecting in memory arguments/results, change to use
global variables or memory-assigned argument/results.
- Allow more registers. E.g. some tests expecting register names
contain only letters (e.g. AX), but it can also contain numbers
(e.g. R10).
- Some instruction selection changes when operate on register vs.
memory, e.g. ADDQ vs. LEAQ, MOVB vs. MOVL. Accept both.
TODO: mathbits.go and memops.go still need fix.
Change-Id: Ic5932b4b5dd3f5d30ed078d296476b641420c4c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/309335
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
x = map[string(byteslice)] is already optimized by the compiler to avoid a
string allocation. This CL generalizes this optimization to:
x = map[T1{ ... Tn{..., string(byteslice), ...} ... }]
where T1 to Tn is a nesting of struct and array literals.
Found in a hot code path that used a struct of strings made from []byte
slices to make a map lookup.
There are no uses of the more generalized optimization in the standard library.
Passes toolstash -cmp.
MapStringConversion/32/simple 21.9ns ± 2% 21.9ns ± 3% ~ (p=0.995 n=17+20)
MapStringConversion/32/struct 28.8ns ± 3% 22.0ns ± 2% -23.80% (p=0.000 n=20+20)
MapStringConversion/32/array 28.5ns ± 2% 21.9ns ± 2% -23.14% (p=0.000 n=19+16)
MapStringConversion/64/simple 21.0ns ± 2% 21.1ns ± 3% ~ (p=0.072 n=19+18)
MapStringConversion/64/struct 72.4ns ± 3% 21.3ns ± 2% -70.53% (p=0.000 n=20+20)
MapStringConversion/64/array 72.8ns ± 1% 21.0ns ± 2% -71.13% (p=0.000 n=17+19)
name old allocs/op new allocs/op delta
MapStringConversion/32/simple 0.00 0.00 ~ (all equal)
MapStringConversion/32/struct 0.00 0.00 ~ (all equal)
MapStringConversion/32/array 0.00 0.00 ~ (all equal)
MapStringConversion/64/simple 0.00 0.00 ~ (all equal)
MapStringConversion/64/struct 1.00 ± 0% 0.00 -100.00% (p=0.000 n=20+20)
MapStringConversion/64/array 1.00 ± 0% 0.00 -100.00% (p=0.000 n=20+20)
Change-Id: I483b4d84d8d74b1025b62c954da9a365e79b7a3a
Reviewed-on: https://go-review.googlesource.com/c/116275
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
replace map clears of the form:
for k := range m {
delete(m, k)
}
(where m is map with key type that is reflexive for ==)
with a new runtime function that clears the maps backing
array with a memclr and reinitializes the hmap struct.
Map key types that for example contain floats are not
replaced by this optimization since NaN keys cannot
be deleted from maps using delete.
name old time/op new time/op delta
GoMapClear/Reflexive/1 92.2ns ± 1% 47.1ns ± 2% -48.89% (p=0.000 n=9+9)
GoMapClear/Reflexive/10 108ns ± 1% 48ns ± 2% -55.68% (p=0.000 n=10+10)
GoMapClear/Reflexive/100 303ns ± 2% 110ns ± 3% -63.56% (p=0.000 n=10+10)
GoMapClear/Reflexive/1000 3.58µs ± 3% 1.23µs ± 2% -65.49% (p=0.000 n=9+10)
GoMapClear/Reflexive/10000 28.2µs ± 3% 10.3µs ± 2% -63.55% (p=0.000 n=9+10)
GoMapClear/NonReflexive/1 121ns ± 2% 124ns ± 7% ~ (p=0.097 n=10+10)
GoMapClear/NonReflexive/10 137ns ± 2% 139ns ± 3% +1.53% (p=0.033 n=10+10)
GoMapClear/NonReflexive/100 331ns ± 3% 334ns ± 2% ~ (p=0.342 n=10+10)
GoMapClear/NonReflexive/1000 3.64µs ± 3% 3.64µs ± 2% ~ (p=0.887 n=9+10)
GoMapClear/NonReflexive/10000 28.1µs ± 2% 28.4µs ± 3% ~ (p=0.247 n=10+10)
Fixes#20138
Change-Id: I181332a8ef434a4f0d89659f492d8711db3f3213
Reviewed-on: https://go-review.googlesource.com/110055
Reviewed-by: Keith Randall <khr@golang.org>
And delete them from asm_test.
Change-Id: I3cf0934706a640136cb0f646509174f8c1bf3363
Reviewed-on: https://go-review.googlesource.com/101395
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
