Call frame allocations can account for significant portion
of all allocations in a program, if call is executed
in an inner loop (e.g. to process every line in a log).
On the other hand, the allocation is easy to remove
using sync.Pool since the allocation is strictly scoped.
benchmark old ns/op new ns/op delta
BenchmarkCall 634 338 -46.69%
BenchmarkCall-4 496 167 -66.33%
benchmark old allocs new allocs delta
BenchmarkCall 1 0 -100.00%
BenchmarkCall-4 1 0 -100.00%
Update #7818
Change-Id: Icf60cce0a9be82e6171f0c0bd80dee2393db54a7
Reviewed-on: https://go-review.googlesource.com/1954
Reviewed-by: Keith Randall <khr@golang.org>
This change extends existing test case to Windows for helping to fix
golang.org/issue/5395.
Change-Id: Iff077fa98ede511981df513f48d84c19375b3e04
Reviewed-on: https://go-review.googlesource.com/3304
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Pointers change from run to run, making it hard to use
the debug output to identify the reason for a changed
object file.
Change-Id: I0c954da0943092c48686afc99ecf75eba516de6a
Reviewed-on: https://go-review.googlesource.com/3352
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Rob Pike <r@golang.org>
ECDSA is unsafe to use if an entropy source produces predictable
output for the ephemeral nonces. E.g., [Nguyen]. A simple
countermeasure is to hash the secret key, the message, and
entropy together to seed a CSPRNG, from which the ephemeral key
is derived.
Fixes#9452
--
This is a minimalist (in terms of patch size) solution, though
not the most parsimonious in its use of primitives:
- csprng_key = ChopMD-256(SHA2-512(priv.D||entropy||hash))
- reader = AES-256-CTR(k=csprng_key)
This, however, provides at most 128-bit collision-resistance,
so that Adv will have a term related to the number of messages
signed that is significantly worse than plain ECDSA. This does
not seem to be of any practical importance.
ChopMD-256(SHA2-512(x)) is used, rather than SHA2-256(x), for
two sets of reasons:
*Practical:* SHA2-512 has a larger state and 16 more rounds; it
is likely non-generically stronger than SHA2-256. And, AFAIK,
cryptanalysis backs this up. (E.g., [Biryukov] gives a
distinguisher on 47-round SHA2-256 with cost < 2^85.) This is
well below a reasonable security-strength target.
*Theoretical:* [Coron] and [Chang] show that Chop-MD(F(x)) is
indifferentiable from a random oracle for slightly beyond the
birthday barrier. It seems likely that this makes a generic
security proof that this construction remains UF-CMA is
possible in the indifferentiability framework.
--
Many thanks to Payman Mohassel for reviewing this construction;
any mistakes are mine, however. And, as he notes, reusing the
private key in this way means that the generic-group (non-RO)
proof of ECDSA's security given in [Brown] no longer directly
applies.
--
[Brown]: http://www.cacr.math.uwaterloo.ca/techreports/2000/corr2000-54.ps
"Brown. The exact security of ECDSA. 2000"
[Coron]: https://www.cs.nyu.edu/~puniya/papers/merkle.pdf
"Coron et al. Merkle-Damgard revisited. 2005"
[Chang]: https://www.iacr.org/archive/fse2008/50860436/50860436.pdf
"Chang and Nandi. Improved indifferentiability security analysis
of chopMD hash function. 2008"
[Biryukov]: http://www.iacr.org/archive/asiacrypt2011/70730269/70730269.pdf
"Biryukov et al. Second-order differential collisions for reduced
SHA-256. 2011"
[Nguyen]: ftp://ftp.di.ens.fr/pub/users/pnguyen/PubECDSA.ps
"Nguyen and Shparlinski. The insecurity of the elliptic curve
digital signature algorithm with partially known nonces. 2003"
New tests:
TestNonceSafety: Check that signatures are safe even with a
broken entropy source.
TestINDCCA: Check that signatures remain non-deterministic
with a functional entropy source.
Updated "golden" KATs in crypto/tls/testdata that use ECDSA suites.
Change-Id: I55337a2fbec2e42a36ce719bd2184793682d678a
Reviewed-on: https://go-review.googlesource.com/3340
Reviewed-by: Adam Langley <agl@golang.org>
The %61 hack was added when runtime was is in C.
Now the Go compiler does the optimization.
Change-Id: I79c3302ec4b931eaaaaffe75e7101c92bf287fc7
Reviewed-on: https://go-review.googlesource.com/3289
Reviewed-by: Keith Randall <khr@golang.org>
BenchmarkClient is intended for profiling
the client without the HTTP server code.
The server code runs in a subprocess.
Change-Id: I9aa128604d0d4e94dc5c0372dc86f962282ed6e8
Reviewed-on: https://go-review.googlesource.com/3164
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Consider the following code:
s := "(" + string(byteSlice) + ")"
Currently we allocate a new string during []byte->string conversion,
and pass it to concatstrings. String allocation is unnecessary in
this case, because concatstrings does memorize the strings for later use.
This change uses slicebytetostringtmp to construct temp string directly
from []byte buffer and passes it to concatstrings.
I've found few such cases in std lib:
s += string(msg[off:off+c]) + "."
buf.WriteString("Sec-WebSocket-Accept: " + string(c.accept) + "\r\n")
bw.WriteString("Sec-WebSocket-Key: " + string(nonce) + "\r\n")
err = xml.Unmarshal([]byte("<Top>"+string(data)+"</Top>"), &logStruct)
d.err = d.syntaxError("invalid XML name: " + string(b))
return m, ProtocolError("malformed MIME header line: " + string(kv))
But there are much more in our internal code base.
Change-Id: I42f401f317131237ddd0cb9786b0940213af16fb
Reviewed-on: https://go-review.googlesource.com/3163
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This is another case where we can say that the address refers to stack.
We create such temps for OSTRUCTLIT initialization.
This eliminates a handful of write barriers today.
But this come up a prerequisite for another change (capturing vars by value),
otherwise we emit writebarriers in writebarrier itself when
capture writebarrier arguments by value.
Change-Id: Ibba93acd0f5431c5a4c3d90ef1e622cb9a7ff50e
Reviewed-on: https://go-review.googlesource.com/3285
Reviewed-by: Russ Cox <rsc@golang.org>
Typecheck for range variables before typechecking for range body.
Body can refer to new vars declared in for range,
so it is preferable to typecheck them before the body.
Makes typecheck order consistent between ORANGE and OFOR.
This come up during another change that computes some predicates
on variables during typechecking.
Change-Id: Ic975db61b1fd5b7f9ee78896d4cc7d93c593c532
Reviewed-on: https://go-review.googlesource.com/3284
Reviewed-by: Russ Cox <rsc@golang.org>
Half of tests currently crash with GODEBUG=wbshadow.
_PageSize is set to 8192. So data can be extended outside
of actually mapped region during rounding. Which leads to crash
during initial copying to shadow.
Use _PhysPageSize instead.
Change-Id: Iaa89992bd57f86dafa16b092b53fdc0606213acb
Reviewed-on: https://go-review.googlesource.com/3286
Reviewed-by: Russ Cox <rsc@golang.org>
Currently we scan maps even if k/v does not contain pointers.
This is required because overflow buckets are hanging off the main table.
This change introduces a separate array that contains pointers to all
overflow buckets and keeps them alive. Buckets themselves are marked
as containing no pointers and are not scanned by GC (if k/v does not
contain pointers).
This brings maps in line with slices and chans -- GC does not scan
their contents if elements do not contain pointers.
Currently scanning of a map[int]int with 2e8 entries (~8GB heap)
takes ~8 seconds. With this change scanning takes negligible time.
Update #9477.
Change-Id: Id8a04066a53d2f743474cad406afb9f30f00eaae
Reviewed-on: https://go-review.googlesource.com/3288
Reviewed-by: Keith Randall <khr@golang.org>
ECDSA is unsafe to use if an entropy source produces predictable
output for the ephemeral nonces. E.g., [Nguyen]. A simple
countermeasure is to hash the secret key, the message, and
entropy together to seed a CSPRNG, from which the ephemeral key
is derived.
--
This is a minimalist (in terms of patch size) solution, though
not the most parsimonious in its use of primitives:
- csprng_key = ChopMD-256(SHA2-512(priv.D||entropy||hash))
- reader = AES-256-CTR(k=csprng_key)
This, however, provides at most 128-bit collision-resistance,
so that Adv will have a term related to the number of messages
signed that is significantly worse than plain ECDSA. This does
not seem to be of any practical importance.
ChopMD-256(SHA2-512(x)) is used, rather than SHA2-256(x), for
two sets of reasons:
*Practical:* SHA2-512 has a larger state and 16 more rounds; it
is likely non-generically stronger than SHA2-256. And, AFAIK,
cryptanalysis backs this up. (E.g., [Biryukov] gives a
distinguisher on 47-round SHA2-256 with cost < 2^85.) This is
well below a reasonable security-strength target.
*Theoretical:* [Coron] and [Chang] show that Chop-MD(F(x)) is
indifferentiable from a random oracle for slightly beyond the
birthday barrier. It seems likely that this makes a generic
security proof that this construction remains UF-CMA is
possible in the indifferentiability framework.
--
Many thanks to Payman Mohassel for reviewing this construction;
any mistakes are mine, however. And, as he notes, reusing the
private key in this way means that the generic-group (non-RO)
proof of ECDSA's security given in [Brown] no longer directly
applies.
--
[Brown]: http://www.cacr.math.uwaterloo.ca/techreports/2000/corr2000-54.ps
"Brown. The exact security of ECDSA. 2000"
[Coron]: https://www.cs.nyu.edu/~puniya/papers/merkle.pdf
"Coron et al. Merkle-Damgard revisited. 2005"
[Chang]: https://www.iacr.org/archive/fse2008/50860436/50860436.pdf
"Chang and Nandi. Improved indifferentiability security analysis
of chopMD hash function. 2008"
[Biryukov]: http://www.iacr.org/archive/asiacrypt2011/70730269/70730269.pdf
"Biryukov et al. Second-order differential collisions for reduced
SHA-256. 2011"
[Nguyen]: ftp://ftp.di.ens.fr/pub/users/pnguyen/PubECDSA.ps
"Nguyen and Shparlinski. The insecurity of the elliptic curve
digital signature algorithm with partially known nonces. 2003"
Fixes#9452
Tests:
TestNonceSafety: Check that signatures are safe even with a
broken entropy source.
TestINDCCA: Check that signatures remain non-deterministic
with a functional entropy source.
Change-Id: Ie7e04057a3a26e6becb80e845ecb5004bb482745
Reviewed-on: https://go-review.googlesource.com/2422
Reviewed-by: Adam Langley <agl@golang.org>
The argument is unused in the C code but will be used in the Go translation,
because the Prog holds information needed to invoke the right meaning
of %A in the ctxt->diag calls in vaddr.
Change-Id: I501830f8ea0e909aafd8ec9ef5d7338e109d9548
Reviewed-on: https://go-review.googlesource.com/3041
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-on: https://go-review.googlesource.com/3310
Reviewed-by: Russ Cox <rsc@golang.org>
- Remove more ? : expressions.
- Use uint32 **hash instead of uint32 *hash[] in function argument.
- Change array.c API to use int, not int32, to match Go's slices.
- Rename strlit to newstrlit, to avoid case-insensitive collision with Strlit.
- Fix a few incorrect printf formats.
- Rename a few variables from 'len' to n or length.
- Eliminate direct string editing building up names like convI2T.
Change-Id: I754cf553402ccdd4963e51b7039f589286219c29
Reviewed-on: https://go-review.googlesource.com/3278
Reviewed-by: Rob Pike <r@golang.org>
cmd/gc contains symbol references into the back end dirs like 6g.
It also contains a few files that include the back end header files and
are compiled separately for each back end, despite being in cmd/gc.
cmd/gc also defines main, which makes at least one reverse symbol
reference unavoidable. (Otherwise you can't get into back-end code.)
This was all expedient, but it's too tightly coupled, especially for a
program written Go.
Make cmd/gc into a true library, letting the back end define main and
call into cmd/gc after making the necessary references available.
cmd/gc being a real library will ease the transition to Go.
Change-Id: I4fb9a0e2b11a32f1d024b3c56fc3bd9ee458842c
Reviewed-on: https://go-review.googlesource.com/3277
Reviewed-by: Rob Pike <r@golang.org>
- Change forward reference to struct Node* to void* in liblink.
- Use explicit (Node*) casts in cmd/gc to get at that field.
- Define struct Array in go.h instead of hiding it in array.c.
- Remove some sizeof(uint32), sizeof(uint64) uses.
- Remove some ? : expressions.
- Rewrite some problematic mid-expression assignments.
Change-Id: I308c70140238a0cfffd90e133f86f442cd0e17d4
Reviewed-on: https://go-review.googlesource.com/3276
Reviewed-by: Rob Pike <r@golang.org>
This change is a recreation of the CL written
by Nick Owens on http://golang.org/cl/150730043.
If the stat buffer is too short, the kernel
informs us by putting the 2-byte size in the
buffer, so we read that and try again.
This follows the same algorithm as /sys/src/libc/9sys/dirfstat.c.
Fixes#8781.
Change-Id: I01b4ad3a5e705dd4cab6673c7a119f8bef9bbd7c
Reviewed-on: https://go-review.googlesource.com/3281
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Creating a tar containing files with 0000 permission bits is
not going to be useful.
Change-Id: Ie489c2891c335d32270b18f37b0e32ecdca536a6
Reviewed-on: https://go-review.googlesource.com/3271
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Previouslly, Stmt.connStmt calls DB.connIfFree on each Stmt.css.
Since Stmt.connStmt locks Stmt.mu, a concurrent use of Stmt causes lock
contention on Stmt.mu.
Additionally, DB.connIfFree locks DB.mu which is shared by DB.addDep and
DB.removeDep.
This change removes DB.connIfFree and makes use of a first unused
connection in idle connection pool to reduce lock contention
without making it complicated.
Fixes#9484
On EC2 c3.8xlarge (E5-2680 v2 @ 2.80GHz * 32 vCPU):
benchmark old ns/op new ns/op delta
BenchmarkManyConcurrentQuery-8 40249 34721 -13.73%
BenchmarkManyConcurrentQuery-16 45610 40176 -11.91%
BenchmarkManyConcurrentQuery-32 109831 43179 -60.69%
benchmark old allocs new allocs delta
BenchmarkManyConcurrentQuery-8 25 25 +0.00%
BenchmarkManyConcurrentQuery-16 25 25 +0.00%
BenchmarkManyConcurrentQuery-32 25 25 +0.00%
benchmark old bytes new bytes delta
BenchmarkManyConcurrentQuery-8 3980 3969 -0.28%
BenchmarkManyConcurrentQuery-16 3980 3982 +0.05%
BenchmarkManyConcurrentQuery-32 3993 3990 -0.08%
Change-Id: Ic96296922c465bac38a260018c58324dae1531d9
Reviewed-on: https://go-review.googlesource.com/2207
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Implemented:
- +, -, *, /, and some unary ops
- all rounding modes
- basic conversions
- string to float conversion
- tests
Missing:
- float to string conversion, formatting
- handling of +/-0 and +/-inf (under- and overflow)
- various TODOs and cleanups
With precision set to 24 or 53, the results match
float32 or float64 operations exactly (excluding
NaNs and denormalized numbers which will not be
supported).
Change-Id: I3121e90fc4b1528e40bb6ff526008da18b3c6520
Reviewed-on: https://go-review.googlesource.com/1218
Reviewed-by: Alan Donovan <adonovan@google.com>
Fix up a couple of minor things pointed out in the last review.
Also:
1. If the symbol starts with center dot, prefix the name with "".
2. If there is no locals size specified, use ArgsSizeUnknown (sic).
3. Do not emit a history point at the start of a macro invocation,
since we do not pop it at the end, behavior consistent with the
old code.
With these changes, old and new assemblers produce identical
output at least for my simple test case, so that provides a verifiable
check for future cleanups.
Change-Id: Iaa91d8e453109824b4be44321ec5e828f39f0299
Reviewed-on: https://go-review.googlesource.com/3242
Reviewed-by: Russ Cox <rsc@golang.org>
Add main.go, the simple driver for the assembler, and the
subdirectory internal/asm, which contains the parser and
instruction generator.
It's likely that much of the implementation is superstition,
or at best experimental phenomenology, but it does generate
working binaries.
Change-Id: I322a9ae8a20174b6693153f30e39217ba68f8032
Reviewed-on: https://go-review.googlesource.com/3196
Reviewed-by: Russ Cox <rsc@golang.org>
Add the lexing code for the new portable assembler.
It is internal to the assembler, so lives in a subdirectory of cmd/asm/internal.
Its only new dependency is the flags package for the assembler, so
add that too; it's trivial. That package manages the command-line
flags in a central place.
The lexer builds on text/scanner to lex the input, including doing a
Plan 9-level implementation of the C preprocessor.
Change-Id: I262e8717b8c797010afaa5051920839906c0dd19
Reviewed-on: https://go-review.googlesource.com/3195
Reviewed-by: Russ Cox <rsc@golang.org>
This simple package holds the definition of the Addr (address) type
that represents addresses inside the assembler.
It has no dependencies.
Change-Id: I7573fd70f1847ef68e3d6b663dc4c39eb2ebf8b3
Reviewed-on: https://go-review.googlesource.com/3193
Reviewed-by: Russ Cox <rsc@golang.org>
This package builds the representation of the machine architecture
for the new assembler.
Almost nothing in it is likely to last but this will get things running.
Change-Id: I8edd891f927a81f76d2dbdcd7484b9c87ac0fb2e
Reviewed-on: https://go-review.googlesource.com/3194
Reviewed-by: Russ Cox <rsc@golang.org>
Rename itod to uitoa to have consistent naming with other itoa functions.
Reduce redundant code by calling uitoa from itoa.
Reduce buffer to maximally needed size for conversion of 64bit integers.
Adjust calls to itoa functions in package net to use new name for itod.
Avoid calls to itoa if uitoa suffices.
Change-Id: I79deaede4d4b0c076a99a4f4dd6f644ba1daec53
Reviewed-on: https://go-review.googlesource.com/2212
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
The compiler has a phase ordering problem. Escape analysis runs
before wrapper generation. When a generated wrapper calls a method
defined in a different package, if that call is inlined, there will be
no escape information for the variables defined in the inlined call.
Those variables will be placed on the stack, which fails if they
actually do escape.
There are probably various complex ways to fix this. This is a simple
way to avoid it: when a generated wrapper calls a method defined in a
different package, treat all local variables as escaping.
Fixes#9537.
Change-Id: I530f39346de16ad173371c6c3f69cc189351a4e9
Reviewed-on: https://go-review.googlesource.com/3092
Reviewed-by: Russ Cox <rsc@golang.org>
cmd/internal/obj reconverted using rsc.io/c2go rev 40275b8.
All Prog*s need Ctxt field set so that the printer can tell
which architecture the Prog belongs to.
Use ctxt.NewProg consistently for this.
Change-Id: Ic981b3d68f24931ffae74a772e83a3dc2fdf518a
Reviewed-on: https://go-review.googlesource.com/3152
Reviewed-by: Rob Pike <r@golang.org>
The build was broken on Plan 9 after the
CL 2994, because of the use of getfields
in src/liblink/go.c.
This happened when building 8l, because
getfield was part of lib9 and tokenize
was part of the Plan 9 libc. However,
both getfields and tokenize depend on
utfrune, causing an incompatibility.
This change enables the build of tokenize
as part of lib9, so it doesn't use
tokenize from the Plan 9 libc anymore.
Change-Id: I2a76903b508bd92771c4754cd53dfc64df350892
Reviewed-on: https://go-review.googlesource.com/3121
Reviewed-by: Minux Ma <minux@golang.org>
Adjust triggergc so that we trigger when we have used 7/8
of the available heap memory. Do first collection when we
exceed 4Mbytes.
Change-Id: I467b4335e16dc9cd1521d687fc1f99a51cc7e54b
Reviewed-on: https://go-review.googlesource.com/3149
Reviewed-by: Austin Clements <austin@google.com>
For new assembler, reconvert using rsc.io/c2go rev f9db76e.
- Removes trailing _ from Go keywords that are exported.
- Export regstr as Register, anames[5689] as Anames.
Also update clients.
Change-Id: I41c8fd2d14490236f548b4aa0ed0b9bd7571d2d7
Reviewed-on: https://go-review.googlesource.com/3151
Reviewed-by: Rob Pike <r@golang.org>
The function getgohostos and getgohostarch
were declared in include/libc.h in CL 3042.
Change-Id: Ib4ff5182cb71cc79a99663ce727fa4c28d15d7ad
Reviewed-on: https://go-review.googlesource.com/3122
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The function runcmd was declared in
include/libc.h in CL 7523043.
Change-Id: I3839b96b2ac0d63e5c2eb4c216710442d0962119
Reviewed-on: https://go-review.googlesource.com/3125
Reviewed-by: Ian Lance Taylor <iant@golang.org>
