David Chase e779bfa5d2 cmd/compile: better modeling of escape across loop levels ... Brief background on "why heap allocate". Things can be forced to the heap for the following reasons: 1) address published, hence lifetime unknown. 2) size unknown/too large, cannot be stack allocated 3) multiplicity unknown/too large, cannot be stack allocated 4) reachable from heap (not necessarily published) The bug here is a case of failing to enforce 4) when an object Y was reachable from a heap allocation X forced because of 3). It was found in the case of a closure allocated within a loop (X) and assigned to a variable outside the loop (multiplicity unknown) where the closure also captured a map (Y) declared outside the loop (reachable from heap). Note the variable declared outside the loop (Y) is not published, has known size, and known multiplicity (one). The only reason for heap allocation is that it was reached from a heap allocated item (X), but because that was not forced by publication, it has to be tracked by loop level, but escape-loop level was not tracked and thus a bug results. The fix is that when a heap allocation is newly discovered, use its looplevel as the minimum loop level for downstream escape flooding. Every attempt to generalize this bug to X-in-loop- references-Y-outside loop succeeded, so the fix was aimed to be general. Anywhere that loop level forces heap allocation, the loop level is tracked. This is not yet tested for all possible X and Y, but it is correctness- conservative and because it caused only one trivial regression in the escape tests, it is probably also performance-conservative. The new test checks the following: 1) in the map case, that if fn escapes, so does the map. 2) in the map case, if fn does not escape, neither does the map. 3) in the &x case, that if fn escapes, so does &x. 4) in the &x case, if fn does not escape, neither does &x. Fixes #13799. Change-Id: Ie280bef2bb86ec869c7c206789d0b68f080c3fdb Reviewed-on: https://go-review.googlesource.com/18234 Run-TryBot: David Chase <drchase@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>		2016-01-13 04:01:00 +00:00
..
bench	encoding/base64: fix streaming decode of padding-free base64	2016-01-08 15:07:45 +00:00
bugs	test: migrate remaining tests to run.go	2014-12-22 22:41:34 +00:00
chan	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
ddd2.dir	…
dwarf	…
fixedbugs	cmd/compile: better modeling of escape across loop levels	2016-01-13 04:01:00 +00:00
import2.dir	…
import4.dir	test: adjust gccgo expected import errors	2015-10-07 14:37:44 +00:00
interface	cmd/internal/gc: improve "type *X has no field or method M" message	2015-05-07 16:21:57 +00:00
ken	…
method4.dir	cmd/gc: do not omit wrapper for expression (interface{...}).F	2014-01-07 13:26:48 +01:00
safe	…
stress	build: adjustments for move from src/pkg to src	2014-09-08 00:06:45 -04:00
syntax	cmd/compile: better syntax error recovery	2015-11-20 19:56:27 +00:00
64bit.go	…
235.go	…
alias.go	…
alias1.go	…
append.go	…
args.go	…
assign.go	cmd/gc: prohibit short variable declarations containing duplicate symbols	2014-10-06 17:16:39 -04:00
assign1.go	…
bigalg.go	…
bigmap.go	…
blank.go	test: revert changes made for Go SSA interpreter test.	2013-10-08 14:36:20 -04:00
blank1.go	cmd/compile: don't allow blank method declarations on builtins	2015-12-02 18:26:38 +00:00
bom.go	…
bombad.go	…
bounds.go	…
chancap.go	…
chanlinear.go	runtime: test for linear enqueue/dequeue behavior	2014-12-08 22:18:17 +00:00
char_lit.go	…
char_lit1.go	…
clearfat.go	[dev.power64] 9g: fix under-zeroing in clearfat	2014-10-31 11:08:27 -04:00
closedchan.go	…
closure.go	…
closure1.go	cmd/gc: capture variables by value	2015-01-29 13:07:30 +00:00
closure2.go	cmd/gc: fix capturing by value for range statements	2015-02-03 15:48:48 +00:00
cmp.go	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
cmp6.go	cmd/gc: do not consider length zero arrays as comparable.	2014-01-31 00:30:56 +01:00
cmplx.go	…
cmplxdivide.c	test: comment the behavior and use of cmplxdivide*	2015-01-15 00:00:06 +00:00
cmplxdivide.go	test: comment the behavior and use of cmplxdivide*	2015-01-15 00:00:06 +00:00
cmplxdivide1.go	…
complit.go	…
complit1.go	cmd/internal/gc: accept map literals with omitted key type	2015-06-04 02:31:38 +00:00
compos.go	…
const.go	cmd/compile: allow huge rsh in constants arithmetic	2015-08-21 20:27:22 +00:00
const1.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
const2.go	…
const3.go	…
const4.go	all: link to https instead of http	2015-07-11 14:36:33 +00:00
const5.go	all: link to https instead of http	2015-07-11 14:36:33 +00:00
const6.go	test: match gccgo error strings.	2013-06-26 18:05:02 +02:00
convT2X.go	…
convert.go	…
convert1.go	…
convert3.go	…
convlit.go	cmd/internal/gc: unsafe.Pointer constants may only be converted to uintptr	2015-05-07 23:54:28 +00:00
convlit1.go	…
copy.go	…
crlf.go	…
ddd.go	…
ddd1.go	…
ddd2.go	…
decl.go	…
declbad.go	…
defer.go	…
deferfin.go	runtime: combine small NoScan allocations	2014-01-24 22:35:11 +04:00
deferprint.go	…
deferprint.out	…
divide.go	…
divmod.go	all: fix a few spelling errors in source comments	2013-12-27 08:59:02 -08:00
empty.go	…
env.go	…
eof.go	…
eof1.go	…
errchk	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
escape.go	…
escape2.go	cmd/compile: better modeling of escape across loop levels	2016-01-13 04:01:00 +00:00
escape2n.go	cmd/compile: better modeling of escape across loop levels	2016-01-13 04:01:00 +00:00
escape3.go	…
escape4.go	cmd/internal/gc: transitive inlining	2015-02-26 17:36:00 +00:00
escape5.go	cmd/internal/gc: move check for large-hence-heap-allocated types into escape analysis	2015-05-22 02:13:54 +00:00
escape_array.go	cmd/internal/gc: move check for large-hence-heap-allocated types into escape analysis	2015-05-22 02:13:54 +00:00
escape_calls.go	cmd/internal/gc: make indirect calls properly escape-y	2015-05-22 01:36:11 +00:00
escape_closure.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_field.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_iface.go	cmd/compile: add case for ODOTTYPE to escwalk	2015-07-30 17:39:44 +00:00
escape_indir.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_level.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_map.go	test: add tests for escape analysis of interface conversions	2015-03-28 16:15:27 +00:00
escape_param.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_slice.go	cmd/internal/gc: extend escape analysis to pointers in slices	2015-05-18 15:34:39 +00:00
escape_struct_param1.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_struct_param2.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
escape_struct_return.go	cmd/internal/gc: improve flow of input params to output params	2015-05-01 13:47:20 +00:00
fibo.go	Fix whitespace (use blanks consistently).	2014-12-08 22:22:58 +00:00
finprofiled.go	runtime: fix finalization and profiling of tiny allocations	2015-11-03 18:57:18 +00:00
float_lit.go	…
float_lit2.go	test: fix two typos in float_lit2.go	2014-05-21 17:19:12 -04:00
float_lit3.go	test/float_lit2.go: rewrite to test values near boundaries	2014-05-21 17:12:06 -04:00
floatcmp.go	…
for.go	…
func.go	…
func1.go	…
func2.go	…
func3.go	…
func4.go	…
func5.go	…
func6.go	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
func7.go	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
func8.go	test: use go:noinline consistently	2015-11-03 02:01:34 +00:00
funcdup.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
funcdup2.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
gc.go	…
gc1.go	…
gc2.go	test: check for build constraints only upto the first blank line	2015-02-06 05:36:26 +00:00
gcstring.go	runtime: fix empty string handling in garbage collector	2014-03-11 23:58:39 -04:00
goprint.go	test: make goprint.go wait longer for go its routine to execute	2013-04-12 16:04:19 -07:00
goprint.out	…
goto.go	Revert "cmd/internal/gc: ignore declarations of types for goto validation"	2015-05-15 16:35:49 +00:00
heapsampling.go	test: really force heap profile update in heapsampling.go	2015-11-12 18:32:13 +00:00
helloworld.go	…
helloworld.out	…
if.go	…
import.go	…
import1.go	test: match gccgo import error messages	2013-12-12 19:02:11 -08:00
import2.go	…
import4.go	…
import5.go	…
index.go	Fix several out of date references to 4g/5g/6g/8g/9g.	2015-06-26 03:38:21 +00:00
index0.go	…
index1.go	…
index2.go	…
indirect.go	…
indirect1.go	…
init.go	…
init1.go	test: deflake init1.go test, tighten its bounds	2015-02-13 22:13:56 +00:00
initcomma.go	…
initialize.go	…
initializerr.go	…
initloop.go	cmd/compile: use []*Node instead of NodeList in sinit	2015-09-05 02:25:01 +00:00
inline.go	cmd/compile: add support for a go:noinline directive	2015-10-29 23:16:27 +00:00
int_lit.go	…
intcvt.go	…
iota.go	…
label.go	…
label1.go	…
linkmain.go	cmd/link: reject non-package main toplevel.a file, remove dead code	2015-12-17 20:59:51 +00:00
linkmain_run.go	test: fix linkmain test	2015-12-17 23:36:13 +00:00
linkx.go	cmd/link: detect -X setting non-string variable	2015-06-29 20:28:36 +00:00
linkx_run.go	cmd/link: detect -X setting non-string variable	2015-06-29 20:28:36 +00:00
literal.go	…
live.go	test: add -update_errors flag to run script	2015-04-10 11:33:42 +00:00
live1.go	cmd/gc: correct liveness for fat variables	2014-02-15 10:58:55 -05:00
live2.go	cmd/gc: allocate non-escaping maps on stack	2015-02-12 09:53:52 +00:00
mallocfin.go	…
map.go	test/mapnan.go: add regression test for non-empty interfaces.	2014-08-06 17:02:55 -04:00
map1.go	…
maplinear.go	test: make maplinear more robust	2014-10-27 18:59:02 -04:00
method.go	…
method1.go	…
method2.go	cmd/gc: fix method values whose receiver is an unnamed interface.	2013-08-29 10:00:58 +02:00
method3.go	…
method4.go	…
method5.go	…
named.go	…
named1.go	cmd/gc: comma-ok assignments produce untyped bool as 2nd result	2014-08-11 16:11:55 -07:00
nil.go	…
nilcheck.go	cmd/gc: optimize existence-only map lookups	2015-01-07 22:36:06 +00:00
nilptr.go	test/nilptr: add more tests	2013-09-05 23:06:34 -04:00
nilptr2.go	test: revert changes made for Go SSA interpreter test.	2013-10-08 14:36:20 -04:00
nilptr3.go	test: fix nosplit.go, fixedbugs/issue11656.go and skip two tests for mips64{,le}	2015-11-12 04:52:31 +00:00
nilptr4.go	cmd/gc: fix bad checknil with ints on 32 bit compilers	2014-02-26 12:25:13 -08:00
nosplit.go	cmd/internal/obj, cmd/link, runtime: increase stack limit to accommodate larger frames on ppc64x	2015-11-12 22:32:16 +00:00
nul1.go	…
parentype.go	…
peano.go	…
print.go	runtime: move built-in print routines to go.	2014-07-31 13:48:48 -07:00
print.out	runtime: move built-in print routines to go.	2014-07-31 13:48:48 -07:00
printbig.go	…
printbig.out	…
range.go	cmd/gc: implement 'for range x {'	2014-07-16 19:27:10 -04:00
recover.go	test: add more cases to recover.go	2014-10-22 08:06:15 -07:00
recover1.go	…
recover2.go	…
recover3.go	tests: remove two misuses of nil pointers	2013-08-15 11:51:04 -04:00
recover4.go	test: move allocation before munmap in recover4	2015-09-16 08:51:48 +00:00
rename.go	…
rename1.go	…
reorder.go	…
reorder2.go	test: use go:noinline consistently	2015-11-03 02:01:34 +00:00
return.go	test: add cases to return.go that gccgo got wrong	2013-08-07 11:31:01 -07:00
rotate.go	…
rotate0.go	test: re-enable rotate tests	2015-05-28 19:40:58 +00:00
rotate1.go	test: re-enable rotate tests	2015-05-28 19:40:58 +00:00
rotate2.go	test: re-enable rotate tests	2015-05-28 19:40:58 +00:00
rotate3.go	test: re-enable rotate tests	2015-05-28 19:40:58 +00:00
run.go	misc/cgo/stdio: reenable tests	2015-12-05 21:24:30 +00:00
rune.go	…
runtime.go	…
shift1.go	test: avoid "declared but not used" errors in shift1.go	2014-07-20 12:25:24 -07:00
shift2.go	test: add shift expression incorrectly rejected by gccgo.	2013-06-25 08:06:34 +02:00
sieve.go	…
sigchld.go	test: skip SIGCHLD test on Plan 9	2014-01-29 09:28:23 +01:00
sigchld.out	…
simassign.go	…
sinit.go	cmd/compile: allow static init for unsafe.Pointer(&x) where x is global	2015-07-07 21:51:57 +00:00
sinit_run.go	all: retire architecture letter in file names, public API	2015-05-21 17:32:17 +00:00
sizeof.go	test: correct sizeof.go.	2013-06-02 19:10:11 +02:00
slice3.go	cmd/gc, runtime: treat slices and strings like pointers in garbage collection	2014-08-25 14:38:19 -04:00
slice3err.go	test: match gccgo error messages	2013-12-12 17:18:12 -08:00
slicecap.go	cmd/gc, runtime: treat slices and strings like pointers in garbage collection	2014-08-25 14:38:19 -04:00
sliceopt.go	cmd/internal/gc: optimize slice + write barrier	2015-05-13 19:20:39 +00:00
solitaire.go	…
stack.go	…
string_lit.go	test: add []rune case to string_lit.go	2013-12-12 17:17:02 -08:00
stringrange.go	…
struct0.go	…
switch.go	…
switch2.go	cmd/compile: address several more 1.6 TODOs in parser	2015-11-21 07:21:23 +00:00
switch3.go	…
switch4.go	…
tinyfin.go	runtime: fix finalization and profiling of tiny allocations	2015-11-03 18:57:18 +00:00
torture.go	cmd/8g: don't allocate a register early for cap(CHAN).	2014-07-01 09:20:51 +02:00
turing.go	…
typecheck.go	cmd/gc: silence assignment errors to undefined symbols	2014-01-03 21:03:20 +01:00
typecheckloop.go	cmd/compile: convert typecheck_stack to []*Node	2015-09-06 23:50:51 +00:00
typeswitch.go	…
typeswitch1.go	…
typeswitch2.go	…
typeswitch3.go	…
undef.go	…
utf.go	…
varerr.go	…
varinit.go	…
writebarrier.go	cmd/internal/gc: add missing write barrier in append(x, BigStructWithPointers)	2015-05-19 15:28:29 +00:00
zerodivide.go	…