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7 Commits

Author SHA1 Message Date
Matthew Dempsky
abefcac10a cmd/compile: skip escape analysis diagnostics for OADDR
For most nodes (e.g., OPTRLIT, OMAKESLICE, OCONVIFACE), escape
analysis prints "escapes to heap" or "does not escape" to indicate
whether that node's allocation can be heap or stack allocated.

These messages are also emitted for OADDR, even though OADDR does not
actually allocate anything itself. Moreover, it's redundant because
escape analysis already prints "moved to heap" diagnostics when an
OADDR node like "&x" causes x to require heap allocation.

Because OADDR nodes don't allocate memory, my escape analysis rewrite
doesn't naturally emit the "escapes to heap" / "does not escape"
diagnostics for them. It's also non-trivial to replicate the exact
semantics esc.go uses for OADDR.

Since there are so many of these messages, I'm disabling them in this
CL by themselves. I modified esc.go to suppress the Warnl calls
without any other behavior changes, and then used a shell script to
automatically remove any ERROR messages mentioned by run.go in
"missing error" or "no match for" lines.

Fixes #16300.
Updates #23109.

Change-Id: I3993e2743c3ff83ccd0893f4e73b366ff8871a57
Reviewed-on: https://go-review.googlesource.com/c/go/+/170319
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
2019-04-02 16:34:03 +00:00
Keith Randall
389e942745 cmd/compile: reuse temporaries in order pass
Instead of allocating a new temporary each time one
is needed, keep a list of temporaries which are free
(have already been VARKILLed on every path) and use
one of them.

Should save a lot of stack space. In a function like this:

func main() {
     fmt.Printf("%d %d\n", 2, 3)
     fmt.Printf("%d %d\n", 4, 5)
     fmt.Printf("%d %d\n", 6, 7)
}

The three [2]interface{} arrays used to hold the ... args
all use the same autotmp, instead of 3 different autotmps
as happened previous to this CL.

Change-Id: I2d728e226f81e05ae68ca8247af62014a1b032d3
Reviewed-on: https://go-review.googlesource.com/c/140301
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-10-14 05:21:00 +00:00
Keith Randall
9a8372f8bd cmd/compile,runtime: remove ambiguously live logic
The previous CL introduced stack objects. This CL removes the old
ambiguously live liveness analysis. After this CL we're relying
on stack objects exclusively.

Update a bunch of liveness tests to reflect the new world.

Fixes #22350

Change-Id: I739b26e015882231011ce6bc1a7f426049e59f31
Reviewed-on: https://go-review.googlesource.com/c/134156
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-10-03 19:54:16 +00:00
Cherry Zhang
beeab6ac02 cmd/compile: fix go:uintptrescapes tag for unnamed parameters
The tag was overwritten by the code for special handling unnamed
parameters.

Fixes #23045.

Change-Id: Ie2e1db3e902a07a2bbbc2a3424cea300f0a42cc3
Reviewed-on: https://go-review.googlesource.com/82775
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2018-02-14 21:41:39 +00:00
David Chase
9c066bab64 cmd/compile: mark temps with new AutoTemp flag, and use it.
This is an extension of
https://go-review.googlesource.com/c/31662/
to mark all the temporaries, not just the ssa-generated ones.

Before-and-after ls -l `go tool -n compile` shows a 3%
reduction in size (or rather, a prior 3% inflation for
failing to filter temps out properly.)

Replaced name-dependent "is it a temp?" tests with calls to
*Node.IsAutoTmp(), which depends on AutoTemp.  Also replace
calls to istemp(n) with n.IsAutoTmp(), to reduce duplication
and clean up function name space.  Generated temporaries
now come with a "." prefix to avoid (apparently harmless)
clashes with legal Go variable names.

Fixes #17644.
Fixes #17240.

Change-Id: If1417f29c79a7275d7303ddf859b51472890fd43
Reviewed-on: https://go-review.googlesource.com/32255
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-10-31 19:38:50 +00:00
Keith Randall
ca4089ad62 cmd/compile: args no longer live until end-of-function
We're dropping this behavior in favor of runtime.KeepAlive.
Implement runtime.KeepAlive as an intrinsic.

Update #15843

Change-Id: Ib60225bd30d6770ece1c3c7d1339a06aa25b1cbc
Reviewed-on: https://go-review.googlesource.com/28310
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-19 16:54:35 +00:00
Ian Lance Taylor
bbe5da4260 cmd/compile, syscall: add //go:uintptrescapes comment, and use it
This new comment can be used to declare that the uintptr arguments to a
function may be converted from pointers, and that those pointers should
be considered to escape. This is used for the Call methods in
dll_windows.go that take uintptr arguments, because they call Syscall.

We can't treat these functions as we do syscall.Syscall, because unlike
Syscall they may cause the stack to grow. For Syscall we can assume that
stack arguments can remain on the stack, but for these functions we need
them to escape.

Fixes #16035.

Change-Id: Ia0e5b4068c04f8d303d95ab9ea394939f1f57454
Reviewed-on: https://go-review.googlesource.com/24551
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-07-06 20:48:41 +00:00