go/test
Keith Randall 7eaa8efbe4 cmd/compile: don't let spills clobber arguments
The compiler allows code to have multiple differently-typed views of a
single argument. For instance, if we have

func f(x float64) {
   y := *(*int64)(unsafe.Pointer(&x))
   ...
}

Then in SSA we get two OpArg ops, one with float64 type and one with
int64 type.

The compiler will try to reuse argument slots for spill slots. It
checks that the argument slot is dead by consulting an interference
graph.

When building the interference graph, we normally ignore cross-type
edges because the values on either end of that edge can't be allocated
to the same slot. (This is just a space-saving optimization.) This
rule breaks down when one of the values is an argument, because of the
multiple views described above. If we're spilling a float64, it is not
enough that the float64 version of x is dead; the int64 version of x
has to be dead also.

Remove the optimization of not recording interference edges if types
don't match. That optimization is incorrect if one of the values
connected by the edge is an argument.

Fixes #23522

Change-Id: I361f85d80fe3bc7249014ca2c3ec887c3dc30271
Reviewed-on: https://go-review.googlesource.com/89335
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-01-23 21:51:55 +00:00
..
alias3.dir [dev.typealias] cmd/compile: export/import test cases for type aliases 2017-01-20 05:55:53 +00:00
bench test/bench/go1: fix typo in parserdata_test.go comment 2017-03-22 03:23:16 +00:00
chan all: fix article typos 2017-09-15 02:39:16 +00:00
closure3.dir cmd/compile: inline closures with captures 2017-11-05 04:18:05 +00:00
ddd2.dir all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
dwarf
fixedbugs cmd/compile: don't let spills clobber arguments 2018-01-23 21:51:55 +00:00
import2.dir all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
import4.dir test: adjust gccgo expected import errors 2015-10-07 14:37:44 +00:00
interface cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
intrinsic.dir cmd/compile: intrinsics for math/bits.TrailingZerosX 2017-03-16 02:44:16 +00:00
ken all: fix spelling mistakes 2016-04-03 17:03:15 +00:00
linkname.dir cmd/compile: include linknames in export data 2017-02-08 20:59:45 +00:00
method4.dir cmd/gc: do not omit wrapper for expression (interface{...}).F 2014-01-07 13:26:48 +01:00
safe
stress all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
syntax cmd/compile/internal/parser: improved a couple of error messages 2017-02-24 18:54:36 +00:00
uintptrescapes.dir cmd/compile, syscall: add //go:uintptrescapes comment, and use it 2016-07-06 20:48:41 +00:00
64bit.go
235.go
alg.go test: add test that required algs get generated 2016-04-24 21:36:52 +00:00
alias.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
alias1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
alias2.go [dev.typealias] cmd/compile: declare methods after resolving receiver type 2017-01-25 08:04:17 +00:00
alias3.go [dev.typealias] cmd/compile: export/import test cases for type aliases 2017-01-20 05:55:53 +00:00
append.go
append1.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
args.go
armimm.go cmd/internal/obj: continue to optimize ARM's constant pool 2017-05-11 13:53:54 +00:00
assign.go cmd/gc: prohibit short variable declarations containing duplicate symbols 2014-10-06 17:16:39 -04:00
assign1.go
atomicload.go cmd/compile: keep value use counts in SSA 2016-03-17 04:20:02 +00:00
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 all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
bounds.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
chancap.go cmd/compile: generate makechan calls with int arguments 2017-08-15 05:54:24 +00:00
chanlinear.go runtime: test for linear enqueue/dequeue behavior 2014-12-08 22:18:17 +00:00
char_lit.go
char_lit1.go
checkbce.go test: add missing copyright header to checkbce.go 2017-05-18 00:05:25 +00:00
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
closure3.go cmd/compile: fix reassignment check 2017-11-03 20:09:26 +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 cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
cmplxdivide.c runtime: make complex division c99 compatible 2017-03-15 22:45:17 +00:00
cmplxdivide.go runtime: make complex division c99 compatible 2017-03-15 22:45:17 +00:00
cmplxdivide1.go runtime: make complex division c99 compatible 2017-03-15 22:45:17 +00:00
complit.go
complit1.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
compos.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
const.go cmd/compile: fix compiler bug for constant equality comparison 2016-09-17 01:12:24 +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 all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
convert.go
convert1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
convert2.go cmd/compile: ignore struct tags when converting structs 2016-10-04 17:10:47 +00:00
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
convT2X.go
copy.go
copy1.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
crlf.go
ddd.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
ddd1.go test: reenable ... test 2017-08-11 17:41:17 +00:00
ddd2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
decl.go
declbad.go
defer.go
deferfin.go runtime: combine small NoScan allocations 2014-01-24 22:35:11 +04:00
deferprint.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
deferprint.out
devirt.go cmd/compile: de-virtualize interface calls 2017-03-14 18:49:23 +00:00
divide.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
divmod.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
empty.go
env.go
eof.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
eof1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
errchk test: skip "# package/path" output from cmd/go in errchk 2017-12-13 21:32:01 +00:00
escape.go
escape2.go test: add missing escape analysis test 2017-08-11 00:56:21 +00:00
escape2n.go test: add missing escape analysis test 2017-08-11 00:56:21 +00:00
escape3.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape4.go cmd/compile: inline calls to local closures 2017-10-11 22:32:36 +00:00
escape5.go cmd/compile: unnamed parameters do not escape 2017-03-24 17:14:00 +00:00
escape_array.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_because.go cmd/compile: add explicit 'where' to EscStep data for explanations 2016-10-26 18:46:59 +00:00
escape_calls.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_closure.go cmd/compile/internal/syntax: establish principled position information 2017-02-15 01:33:03 +00:00
escape_field.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_iface.go cmd/compile: avoid leak of dottype expression on double assignment form 2016-10-10 12:09:16 +00:00
escape_indir.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_level.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_map.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_param.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_slice.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_struct_param1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_struct_param2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
escape_struct_return.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +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/float_lit2: fix expressions in comment 2016-09-14 16:39:47 +00:00
float_lit3.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
floatcmp.go
for.go
func.go
func1.go
func2.go
func3.go
func4.go
func5.go
func6.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
func7.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
func8.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
funcdup.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
funcdup2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
gc.go
gc1.go
gc2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
gcstring.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
goprint.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
goprint.out
goto.go cmd/compile: report block start for gotos jumping into blocks 2017-04-19 02:27:58 +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 all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
import4.go
import5.go cmd/compile: be slightly more tolerant in case of certain syntax errors 2017-03-24 20:07:15 +00:00
import6.go cmd/compile/internal/syntax: removed gcCompat code needed to pass orig. tests 2017-02-10 01:22:30 +00:00
index.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
index0.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
index1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
index2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
indirect.go
indirect1.go
init.go Revert "cmd/compile: improve error message if init is directly invoked" 2017-03-06 23:48:37 +00:00
init1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
initcomma.go
initialize.go
initializerr.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
initloop.go cmd/compile: use []*Node instead of NodeList in sinit 2015-09-05 02:25:01 +00:00
inline.go cmd/compile: inline closures with captures 2017-11-05 04:18:05 +00:00
inline_caller.go runtime: skip logical frames in runtime.Caller 2017-04-18 19:56:30 +00:00
inline_callers.go test: make inline_callers.go test not inline the runtime 2017-11-22 00:52:54 +00:00
inline_literal.go cmd/compile: copy literals when inlining 2017-03-03 21:29:32 +00:00
inline_variadic.go cmd/compile: generate code that type checks when inlining variadic functions 2016-11-30 19:46:00 +00:00
int_lit.go
intcvt.go
intrinsic.go cmd/compile: intrinsify Ctz{32,64} and Bswap{32,64} on s390x 2016-09-19 19:03:01 +00:00
intrinsic_atomic.go cmd/compile: intrinsify atomics on MIPS64 2017-10-10 19:43:38 +00:00
iota.go
label.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
label1.go cmd/compile/internal/gc: don't panic on continue in switch 2017-04-12 14:27:45 +00:00
linkmain.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
linkmain_run.go test: fix linkmain test 2015-12-17 23:36:13 +00:00
linkname.go cmd/compile: include linknames in export data 2017-02-08 20:59:45 +00:00
linkobj.go cmd/compile: add -linkobj flag to allow writing object file in two parts 2016-05-09 17:31:45 +00:00
linkx.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
linkx_run.go test: print output on link -X failure 2016-04-20 17:37:35 +00:00
literal.go
live.go cmd/compile: specialize map creation for small hint sizes 2017-11-02 17:03:45 +00:00
live1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
live2.go cmd/compile: specialize map creation for small hint sizes 2017-11-02 17:03:45 +00:00
live_syscall.go cmd/compile: fix unsafe.Pointer liveness for Syscall-like functions 2017-12-08 21:34:24 +00:00
locklinear.go test: deflake locklinear again 2017-04-05 18:46:31 +00:00
loopbce.go cmd/compile: make loop guard+rotate conditional on GOEXPERIMENT 2017-06-21 22:07:33 +00:00
makechan.go cmd/compile: generate makechan calls with int arguments 2017-08-15 05:54:24 +00:00
makemap.go cmd/compile: generate makemap calls with int arguments 2017-08-22 20:28:21 +00:00
makenew.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +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 cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
maplinear.go test: make maplinear more robust 2014-10-27 18:59:02 -04:00
mergemul.go cmd/compile: combine x*n - y*n into (x-y)*n 2017-09-03 14:29:38 +00:00
method.go
method1.go cmd/compile: ignore receiver parameters in Eqtype 2016-03-17 00:38:15 +00:00
method2.go cmd/compile: add two error position tests for the typechecker 2017-10-12 20:50:20 +00:00
method3.go
method4.go
method5.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
method6.go cmd/compile: add two error position tests for the typechecker 2017-10-12 20:50:20 +00:00
method7.go test: disable broken test for 1.10 2017-12-04 19:29:14 +00:00
named.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
named1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
nil.go
nilcheck.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
nilptr.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
nilptr2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
nilptr3.go cmd/compile: remove more nil ptr checks after newobject 2017-08-25 03:26:58 +00:00
nilptr4.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
nosplit.go test: fix and re-enable nosplit.go 2017-10-31 19:12:11 +00:00
notinheap.go cmd/compile/internal/gc: inline typedcl0 and typedcl1 2017-02-01 22:52:32 +00:00
notinheap2.go cmd/compile: add go:notinheap type pragma 2016-10-15 17:58:14 +00:00
notinheap3.go cmd/compile: []T where T is go:notinheap does not need write barriers 2017-11-06 21:07:57 +00:00
nowritebarrier.go cmd/compile: improve coverage of nowritebarrierrec check 2017-10-29 19:36:44 +00:00
nul1.go cmd/compile/internal/gc: enable new parser by default 2016-10-25 22:28:40 +00:00
opt_branchlikely.go cmd/compile: insert scheduling checks on loop backedges 2017-01-09 21:01:29 +00:00
parentype.go
peano.go
phiopt.go test: re-enable phi optimization test 2016-09-13 20:06:13 +00:00
print.go cmd/compile: fix print/println when input is uint 2017-09-26 04:08:38 +00:00
print.out cmd/compile: fix print/println when input is uint 2017-09-26 04:08:38 +00:00
printbig.go
printbig.out
prove.go cmd/compile/internal/gc: improve comparison with constant strings 2017-04-07 15:40:25 +00:00
range.go cmd/compile: improve single blank variable handling in walkrange 2017-09-12 05:50:54 +00:00
README.md test: add README 2017-07-26 23:37:25 +00:00
recover.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
recover1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
recover2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
recover3.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
recover4.go all: use Fatalf instead of Fatal if format is given 2018-01-10 01:35:45 +00:00
recover5.go cmd/compile: more error position tests for the typechecker 2017-04-24 12:37:49 +00:00
reflectmethod1.go cmd/compile: track reflect.Type.Method in deadcode 2016-03-11 21:19:20 +00:00
reflectmethod2.go cmd/compile: track reflect.Type.Method in deadcode 2016-03-11 21:19:20 +00:00
reflectmethod3.go cmd/compile: track reflect.Type.Method in deadcode 2016-03-11 21:19:20 +00:00
reflectmethod4.go cmd/link: treat reflect.Value.Method like Call 2016-03-11 22:07:02 +00:00
rename.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rename1.go cmd/compile: avoid duplicate cast error 2017-08-22 13:44:35 +00:00
reorder.go cmd/compile: Ensure left-to-right assignment 2017-02-11 21:46:21 +00:00
reorder2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
return.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rotate.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rotate0.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rotate1.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rotate2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
rotate3.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
run.go cmd/compile: make -asmhdr work with type aliases 2017-11-29 20:40:41 +00:00
rune.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
runtime.go cmd/compile/internal/gc: separate builtin and real runtime packages 2017-03-01 01:06:32 +00:00
shift1.go cmd/compile: permit indices of certain non-constant shifts 2017-12-01 20:39:50 +00:00
shift2.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
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 all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
sinit_run.go all: retire architecture letter in file names, public API 2015-05-21 17:32:17 +00:00
sizeof.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
slice3.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
slice3err.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
slicecap.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
sliceopt.go cmd/compile: use masks instead of branches for slicing 2016-10-27 20:22:49 +00:00
solitaire.go
stack.go
strength.go cmd/compile: generalize strength reduction of mulq 2016-03-30 22:27:13 +00:00
string_lit.go test: add []rune case to string_lit.go 2013-12-12 17:17:02 -08:00
stringrange.go
struct0.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
switch.go
switch2.go cmd/compile/internal/syntax: match old parser errors and line numbers 2016-08-19 01:10:21 +00:00
switch3.go
switch4.go
switch5.go cmd/compile: make duplicate expr cases readable 2017-05-19 18:11:51 +00:00
switch6.go cmd/compile: improve error for wrong type in switch 2017-02-02 17:36:43 +00:00
switch7.go cmd/compile: make duplicate expr cases readable 2017-05-19 18:11:51 +00:00
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 cmd/compile/internal/syntax: removed gcCompat code needed to pass orig. tests 2017-02-10 01:22:30 +00:00
typeswitch3.go cmd/compile: add test for non interface type switch 2017-03-25 22:52:54 +00:00
uintptrescapes.go cmd/compile, syscall: add //go:uintptrescapes comment, and use it 2016-07-06 20:48:41 +00:00
uintptrescapes2.go cmd/compile: mark temps with new AutoTemp flag, and use it. 2016-10-31 19:38:50 +00:00
undef.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
utf.go
varerr.go all: make copyright headers consistent with one space after period 2016-05-02 13:43:18 +00:00
varinit.go
writebarrier.go cmd/compile: don't use statictmps for SSA-able composite literals 2017-05-11 18:28:40 +00:00
zerodivide.go test: lock in test for _ assignment evaluation/zerodivide panic 2016-12-23 17:35:24 +00:00

The test directory contains tests of the Go tool chain and runtime. It includes black box tests, regression tests, and error output tests. They are run as part of all.bash.

To run just these tests, execute:

go run run.go

Standard library tests should be written as regular Go tests in the appropriate package.

The tool chain and runtime also have regular Go tests in their packages. The main reasons to add a new test to this directory are:

  • it is most naturally expressed using the test runner; or
  • it is also applicable to gccgo and other Go tool chains.