mirror of https://github.com/golang/go.git
7fbb1b36c3
This includes the following information in the per-function summary:
outK = paramJ encoded in outK bits for paramJ
outK = *paramJ encoded in outK bits for paramJ
heap = paramJ EscHeap
heap = *paramJ EscContentEscapes
Note that (currently) if the address of a parameter is taken and
returned, necessarily a heap allocation occurred to contain that
reference, and the heap can never refer to stack, therefore the
parameter and everything downstream from it escapes to the heap.
The per-function summary information now has a tuneable number of bits
(2 is probably noticeably better than 1, 3 is likely overkill, but it
is now easy to check and the -m debugging output includes information
that allows you to figure out if more would be better.)
A new test was added to check pointer flow through struct-typed and
*struct-typed parameters and returns; some of these are sensitive to
the number of summary bits, and ought to yield better results with a
more competent escape analysis algorithm. Another new test checks
(some) correctness with array parameters, results, and operations.
The old analysis inferred a piece of plan9 runtime was non-escaping by
counteracting overconservative analysis with buggy analysis; with the
bug fixed, the result was too conservative (and it's not easy to fix
in this framework) so the source code was tweaked to get the desired
result. A test was added against the discovered bug.
The escape analysis was further improved splitting the "level" into
3 parts, one tracking the conventional "level" and the other two
computing the highest-level-suffix-from-copy, which is used to
generally model the cancelling effect of indirection applied to
address-of.
With the improved escape analysis enabled, it was necessary to
modify one of the runtime tests because it now attempts to allocate
too much on the (small, fixed-size) G0 (system) stack and this
failed the test.
Compiling src/std after touching src/runtime/*.go with -m logging
turned on shows 420 fewer heap allocation sites (10538 vs 10968).
Profiling allocations in src/html/template with
for i in {1..5} ;
do go tool 6g -memprofile=mastx.${i}.prof -memprofilerate=1 *.go;
go tool pprof -alloc_objects -text mastx.${i}.prof ;
done
showed a 15% reduction in allocations performed by the compiler.
Update #3753
Update #4720
Fixes #10466
Change-Id: I0fd97d5f5ac527b45f49e2218d158a6e89951432
Reviewed-on: https://go-review.googlesource.com/8202
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
|
||
|---|---|---|
| .. | ||
| bench | ||
| bugs | ||
| chan | ||
| ddd2.dir | ||
| dwarf | ||
| fixedbugs | ||
| import2.dir | ||
| import4.dir | ||
| interface | ||
| ken | ||
| method4.dir | ||
| safe | ||
| stress | ||
| syntax | ||
| 64bit.go | ||
| 235.go | ||
| alias.go | ||
| alias1.go | ||
| append.go | ||
| args.go | ||
| assign.go | ||
| assign1.go | ||
| bigalg.go | ||
| bigmap.go | ||
| blank.go | ||
| blank1.go | ||
| bom.go | ||
| bombad.go | ||
| bounds.go | ||
| chancap.go | ||
| chanlinear.go | ||
| char_lit.go | ||
| char_lit1.go | ||
| clearfat.go | ||
| closedchan.go | ||
| closure.go | ||
| closure1.go | ||
| closure2.go | ||
| cmp.go | ||
| cmp6.go | ||
| cmplx.go | ||
| cmplxdivide.c | ||
| cmplxdivide.go | ||
| cmplxdivide1.go | ||
| complit.go | ||
| complit1.go | ||
| compos.go | ||
| const.go | ||
| const1.go | ||
| const2.go | ||
| const3.go | ||
| const4.go | ||
| const5.go | ||
| const6.go | ||
| convT2X.go | ||
| convert.go | ||
| convert1.go | ||
| convert3.go | ||
| convlit.go | ||
| convlit1.go | ||
| copy.go | ||
| crlf.go | ||
| ddd.go | ||
| ddd1.go | ||
| ddd2.go | ||
| decl.go | ||
| declbad.go | ||
| defer.go | ||
| deferfin.go | ||
| deferprint.go | ||
| deferprint.out | ||
| divide.go | ||
| divmod.go | ||
| empty.go | ||
| env.go | ||
| eof.go | ||
| eof1.go | ||
| errchk | ||
| escape.go | ||
| escape2.go | ||
| escape2n.go | ||
| escape3.go | ||
| escape4.go | ||
| escape5.go | ||
| escape_array.go | ||
| escape_calls.go | ||
| escape_closure.go | ||
| escape_field.go | ||
| escape_iface.go | ||
| escape_indir.go | ||
| escape_level.go | ||
| escape_map.go | ||
| escape_param.go | ||
| escape_slice.go | ||
| escape_struct_param1.go | ||
| escape_struct_param2.go | ||
| escape_struct_return.go | ||
| fibo.go | ||
| float_lit.go | ||
| float_lit2.go | ||
| float_lit3.go | ||
| floatcmp.go | ||
| for.go | ||
| func.go | ||
| func1.go | ||
| func2.go | ||
| func3.go | ||
| func4.go | ||
| func5.go | ||
| func6.go | ||
| func7.go | ||
| func8.go | ||
| funcdup.go | ||
| funcdup2.go | ||
| gc.go | ||
| gc1.go | ||
| gc2.go | ||
| gcstring.go | ||
| goprint.go | ||
| goprint.out | ||
| goto.go | ||
| helloworld.go | ||
| helloworld.out | ||
| if.go | ||
| import.go | ||
| import1.go | ||
| import2.go | ||
| import4.go | ||
| import5.go | ||
| index.go | ||
| index0.go | ||
| index1.go | ||
| index2.go | ||
| indirect.go | ||
| indirect1.go | ||
| init.go | ||
| init1.go | ||
| initcomma.go | ||
| initialize.go | ||
| initializerr.go | ||
| inline.go | ||
| int_lit.go | ||
| intcvt.go | ||
| iota.go | ||
| label.go | ||
| label1.go | ||
| linkx.go | ||
| linkx_run.go | ||
| literal.go | ||
| live.go | ||
| live1.go | ||
| live2.go | ||
| mallocfin.go | ||
| map.go | ||
| map1.go | ||
| maplinear.go | ||
| method.go | ||
| method1.go | ||
| method2.go | ||
| method3.go | ||
| method4.go | ||
| method5.go | ||
| named.go | ||
| named1.go | ||
| nil.go | ||
| nilcheck.go | ||
| nilptr.go | ||
| nilptr2.go | ||
| nilptr3.go | ||
| nilptr4.go | ||
| nosplit.go | ||
| nul1.go | ||
| parentype.go | ||
| peano.go | ||
| print.go | ||
| print.out | ||
| printbig.go | ||
| printbig.out | ||
| range.go | ||
| recover.go | ||
| recover1.go | ||
| recover2.go | ||
| recover3.go | ||
| recover4.go | ||
| rename.go | ||
| rename1.go | ||
| reorder.go | ||
| reorder2.go | ||
| return.go | ||
| rotate.go | ||
| rotate0.go | ||
| rotate1.go | ||
| rotate2.go | ||
| rotate3.go | ||
| run.go | ||
| rune.go | ||
| runtime.go | ||
| shift1.go | ||
| shift2.go | ||
| sieve.go | ||
| sigchld.go | ||
| sigchld.out | ||
| simassign.go | ||
| sinit.go | ||
| sinit_run.go | ||
| sizeof.go | ||
| slice3.go | ||
| slice3err.go | ||
| slicecap.go | ||
| solitaire.go | ||
| stack.go | ||
| string_lit.go | ||
| stringrange.go | ||
| struct0.go | ||
| switch.go | ||
| switch3.go | ||
| switch4.go | ||
| tinyfin.go | ||
| torture.go | ||
| turing.go | ||
| typecheck.go | ||
| typeswitch.go | ||
| typeswitch1.go | ||
| typeswitch2.go | ||
| typeswitch3.go | ||
| undef.go | ||
| utf.go | ||
| varerr.go | ||
| varinit.go | ||
| writebarrier.go | ||
| zerodivide.go | ||