[dev.typeparams] all: merge dev.regabi (7e0a81d) into dev.typeparams

As with CL 285875, this required resolving some conflicts around
handling of //go:embed directives. Still further work is needed to
reject uses of //go:embed in files that don't import "embed", so this
is left as a TODO. (When this code was written for dev.typeparams, we
were still leaning towards not requiring the "embed" import.)

Also, the recent support for inlining closures (CL 283112) interacts
poorly with -G=3 mode. There are some known issues with this code
already (#43818), so for now this CL disables inlining of closures
when in -G=3 mode with a TODO to revisit this once closure inlining is
working fully.

Conflicts:

- src/cmd/compile/internal/noder/noder.go
- src/cmd/compile/internal/typecheck/dcl.go
- src/cmd/compile/internal/typecheck/func.go
- test/run.go

Merge List:

+ 2021-01-22 7e0a81d280 [dev.regabi] all: merge master (dab3e5a) into dev.regabi
+ 2021-01-22 dab3e5affe runtime: switch runtime to libc for openbsd/amd64
+ 2021-01-22 a1b53d85da cmd/go: add documentation for test and xtest fields output by go list
+ 2021-01-22 b268b60774 runtime: remove pthread_kill/pthread_self for openbsd
+ 2021-01-22 ec4051763d runtime: fix typo in mgcscavenge.go
+ 2021-01-22 7ece3a7b17 net/http: fix flaky TestDisableKeepAliveUpgrade
+ 2021-01-22 50cba0506f time: clarify Timer.Reset behavior on AfterFunc Timers
+ 2021-01-22 cf10e69f17 doc/go1.16: mention net/http.Transport.GetProxyConnectHeader
+ 2021-01-22 ec1b945265 doc/go1.16: mention path/filepath.WalkDir
+ 2021-01-22 11def3d40b doc/go1.16: mention syscall.AllThreadsSyscall
+ 2021-01-21 07b0235609 doc/go1.16: add notes about package-specific fs.FS changes
+ 2021-01-21 e2b4f1fea5 doc/go1.16: minor formatting fix
+ 2021-01-21 9f43a9e07b doc/go1.16: mention new debug/elf constants
+ 2021-01-21 3c2f11ba5b cmd/go: overwrite program name with full path
+ 2021-01-21 953d1feca9 all: introduce and use internal/execabs
+ 2021-01-21 b186e4d70d cmd/go: add test case for cgo CC setting
+ 2021-01-21 5a8a2265fb cmd/cgo: report exec errors a bit more clearly
+ 2021-01-21 46e2e2e9d9 cmd/go: pass resolved CC, GCCGO to cgo
+ 2021-01-21 3d40895e36 runtime: switch openbsd/arm64 to pthreads
+ 2021-01-21 d95ca91380 crypto/elliptic: fix P-224 field reduction
+ 2021-01-21 d7e71c01ad [dev.regabi] cmd/compile: replace ir.Name map with ir.NameSet for dwarf
+ 2021-01-21 5248f59a22 [dev.regabi] cmd/compile: replace ir.Name map with ir.NameSet for SSA
+ 2021-01-21 970d8b6cb2 [dev.regabi] cmd/compile: replace ir.Name map with ir.NameSet in inlining
+ 2021-01-21 68a4664475 [dev.regabi] cmd/compile: remove tempAssigns in walkCall1
+ 2021-01-21 fd9a391cdd [dev.regabi] cmd/compile: remove CallExpr.Rargs
+ 2021-01-21 19a6db6b63 [dev.regabi] cmd/compile: make sure mkcall* passed non-nil init
+ 2021-01-21 9f036844db [dev.regabi] cmd/compile: use ir.DoChildren directly in inlining
+ 2021-01-21 213c3905e9 [dev.regabi] cmd/compile: use node walked flag to prevent double walk for walkSelect
+ 2021-01-20 1760d736f6 [dev.regabi] cmd/compile: exporting, importing, and inlining functions with OCLOSURE
+ 2021-01-20 ecf4ebf100 cmd/internal/moddeps: check content of all modules in GOROOT
+ 2021-01-20 92cb157cf3 [dev.regabi] cmd/compile: late expansion of return values
+ 2021-01-20 d2d155d1ae runtime: don't adjust timer pp field in timerWaiting status
+ 2021-01-20 803d18fc6c cmd/go: set Incomplete field on go list output if no files match embed
+ 2021-01-20 6e243ce71d cmd/go: have go mod vendor copy embedded files in subdirs
+ 2021-01-20 be28e5abc5 cmd/go: fix mod_get_fallback test
+ 2021-01-20 928bda4f4a runtime: convert openbsd/amd64 locking to libc
+ 2021-01-19 824f2d635c cmd/go: allow go fmt to complete when embedded file is missing
+ 2021-01-19 0575e35e50 cmd/compile: require 'go 1.16' go.mod line for //go:embed
+ 2021-01-19 9423d50d53 [dev.regabi] cmd/compile: use '%q' for printing rune values less than 128
+ 2021-01-19 ccb2e90688 cmd/link: exit before Asmb2 if error
+ 2021-01-19 ca5774a5a5 embed: treat uninitialized FS as empty
+ 2021-01-19 d047c91a6c cmd/link,runtime: switch openbsd/amd64 to pthreads
+ 2021-01-19 61debffd97 runtime: factor out usesLibcall
+ 2021-01-19 9fed39d281 runtime: factor out mStackIsSystemAllocated
+ 2021-01-19 a2f825c542 [dev.regabi] cmd/compile: directly create go.map and go.track symbols
+ 2021-01-19 4a4212c0e5 [dev.regabi] cmd/compile: refactor Linksym creation
+ 2021-01-19 4f5c603c0f [dev.regabi] cmd/compile: cleanup callTargetLSym
+ 2021-01-18 dbab079835 runtime: free Windows event handles after last lock is dropped
+ 2021-01-18 5a8fbb0d2d os: do not close syscall.Stdin in TestReadStdin
+ 2021-01-18 422f38fb6c [dev.regabi] cmd/compile: move stack objects to liveness
+ 2021-01-18 6113db0bb4 [dev.regabi] cmd/compile: convert OPANIC argument to interface{} during typecheck
+ 2021-01-18 4c835f9169 [dev.regabi] cmd/compile: use LinksymOffsetExpr in TypePtr/ItabAddr
+ 2021-01-18 0ffa1ead6e [dev.regabi] cmd/compile: use *obj.LSym instead of *ir.Name for staticdata functions
+ 2021-01-17 7e0fa38aad [dev.regabi] cmd/compile: remove unneeded packages from ir.Pkgs
+ 2021-01-17 99a5db11ac [dev.regabi] cmd/compile: use LinksymOffsetExpr in walkConvInterface
+ 2021-01-17 87845d14f9 [dev.regabi] cmd/compile: add ir.TailCallStmt
+ 2021-01-17 e3027c6828 [dev.regabi] cmd/compile: fix linux-amd64-noopt builder
+ 2021-01-17 59ff93fe64 [dev.regabi] cmd/compile: rename NameOffsetExpr to LinksymOffsetExpr
+ 2021-01-17 82b9cae700 [dev.regabi] cmd/compile: change ir.NameOffsetExpr to use *obj.LSym instead of *Name
+ 2021-01-17 88956fc4b1 [dev.regabi] cmd/compile: stop analyze NameOffsetExpr.Name_ in escape analysis
+ 2021-01-17 7ce2a8383d [dev.regabi] cmd/compile: simplify stack temp initialization
+ 2021-01-17 ba0e8a92fa [dev.regabi] cmd/compile: refactor temp construction in walk
+ 2021-01-17 78e5aabcdb [dev.regabi] cmd/compile: replace Node.HasCall with walk.mayCall
+ 2021-01-16 6de9423445 [dev.regabi] cmd/compile: cleanup OAS2FUNC ordering
+ 2021-01-16 a956a0e909 [dev.regabi] cmd/compile, runtime: fix up comments/error messages from recent renames
+ 2021-01-16 ab3b67abfd [dev.regabi] cmd/compile: remove ONEWOBJ
+ 2021-01-16 c9b1445ac8 [dev.regabi] cmd/compile: remove TypeAssertExpr {Src,Dst}Type fields
+ 2021-01-15 682a1d2176 runtime: detect errors in DuplicateHandle
+ 2021-01-15 9f83418b83 cmd/link: remove GOROOT write in TestBuildForTvOS
+ 2021-01-15 ec9470162f cmd/compile: allow embed into any string or byte slice type
+ 2021-01-15 54198b04db cmd/compile: disallow embed of var inside func
+ 2021-01-15 b386c735e7 cmd/go: fix go generate docs
+ 2021-01-15 bb5075a525 syscall: remove RtlGenRandom and move it into internal/syscall
+ 2021-01-15 1deae0b597 os: invoke processKiller synchronously in testKillProcess
+ 2021-01-15 03a875137f [dev.regabi] cmd/compile: unexport reflectdata.WriteType
+ 2021-01-15 14537e6e54 [dev.regabi] cmd/compile: move stkobj symbol generation to SSA
+ 2021-01-15 ab523fc510 [dev.regabi] cmd/compile: don't promote Byval CaptureVars if Addrtaken
+ 2021-01-15 ff196c3e84 crypto/x509: update iOS bundled roots to version 55188.40.9
+ 2021-01-15 b7a698c73f [dev.regabi] test: disable test on windows because expected contains path separators.
+ 2021-01-15 4be7af23f9 [dev.regabi] cmd/compile: fix ICE during ir.Dump
+ 2021-01-14 e125ccd10e cmd/go: in 'go mod edit', validate versions given to -retract and -exclude
+ 2021-01-14 eb330020dc cmd/dist, cmd/go: pass -arch for C compilation on Darwin
+ 2021-01-14 84e8a06f62 cmd/cgo: remove unnecessary space in cgo export header
+ 2021-01-14 0c86b999c3 cmd/test2json: document passing -test.paniconexit0
+ 2021-01-14 9135795891 cmd/go/internal/load: report positions for embed errors
+ 2021-01-14 35b9c66601 [dev.regabi] cmd/compile,cmd/link: additional code review suggestions for CL 270863
+ 2021-01-14 d9b79e53bb cmd/compile: fix wrong complement for arm64 floating-point comparisons
+ 2021-01-14 c73232d08f cmd/go/internal/load: refactor setErrorPos to PackageError.setPos
+ 2021-01-14 6aa28d3e06 go/build: report positions for go:embed directives
+ 2021-01-14 9734fd482d [dev.regabi] cmd/compile: use node walked flag to prevent double walk for walkSwitch
+ 2021-01-14 f97983249a [dev.regabi] cmd/compile: move more PAUTOHEAP to SSA construction
+ 2021-01-14 4476300425 [dev.regabi] cmd/compile: use byte for CallExpr.Use
+ 2021-01-14 5a5ab24689 [dev.regabi] cmd/compile: do not rely on CallExpr.Rargs for detect already walked calls
+ 2021-01-14 983ac4b086 [dev.regabi] cmd/compile: fix ICE when initializing blank vars
+ 2021-01-13 7eb31d999c cmd/go: add hints to more missing sum error messages
+ 2021-01-13 d6d4673728 [dev.regabi] cmd/compile: fix GOEXPERIMENT=regabi builder
+ 2021-01-13 c41b999ad4 [dev.regabi] cmd/compile: refactor abiutils from "gc" into new "abi"
+ 2021-01-13 861707a8c8 [dev.regabi] cmd/compile: added limited //go:registerparams pragma for new ABI dev
+ 2021-01-13 c1370e918f [dev.regabi] cmd/compile: add code to support register ABI spills around morestack calls
+ 2021-01-13 2abd24f3b7 [dev.regabi] test: make run.go error messages slightly more informative
+ 2021-01-13 9a19481acb [dev.regabi] cmd/compile: make ordering for InvertFlags more stable
+ 2021-01-12 ba76567bc2 cmd/go/internal/modload: delete unused *mvsReqs.next method
+ 2021-01-12 665def2c11 encoding/asn1: document unmarshaling behavior for IMPLICIT string fields
+ 2021-01-11 81ea89adf3 cmd/go: fix non-script staleness checks interacting badly with GOFLAGS
+ 2021-01-11 759309029f doc: update editors.html for Go 1.16
+ 2021-01-11 c3b4c7093a cmd/internal/objfile: don't require runtime.symtab symbol for XCOFF
+ 2021-01-08 59bfc18e34 cmd/go: add hint to read 'go help vcs' to GOVCS errors
+ 2021-01-08 cd6f3a54e4 cmd/go: revise 'go help' documentation for modules
+ 2021-01-08 6192b98751 cmd/go: make hints in error messages more consistent
+ 2021-01-08 25886cf4bd cmd/go: preserve sums for indirect deps fetched by 'go mod download'
+ 2021-01-08 6250833911 runtime/metrics: mark histogram metrics as cumulative
+ 2021-01-08 8f6a9acbb3 runtime/metrics: remove unused StopTheWorld Description field
+ 2021-01-08 6598c65646 cmd/compile: fix exponential-time init-cycle reporting
+ 2021-01-08 fefad1dc85 test: fix timeout code for invoking compiler
+ 2021-01-08 6728118e0a cmd/go: pass signals forward during "go tool"
+ 2021-01-08 e65c543f3c go/build/constraint: add parser for build tag constraint expressions
+ 2021-01-08 0c5afc4fb7 testing/fstest,os: clarify racy behavior of TestFS
+ 2021-01-08 32afcc9436 runtime/metrics: change unit on *-by-size metrics to match bucket unit
+ 2021-01-08 c6513bca5a io/fs: minor corrections to Glob doc
+ 2021-01-08 304f769ffc cmd/compile: don't short-circuit copies whose source is volatile
+ 2021-01-08 ae97717133 runtime,runtime/metrics: use explicit histogram boundaries
+ 2021-01-08 a9ccd2d795 go/build: skip string literal while findEmbed
+ 2021-01-08 d92f8add32 archive/tar: fix typo in comment
+ 2021-01-08 cab1202183 cmd/link: accept extra blocks in TestFallocate
+ 2021-01-08 ee4d32249b io/fs: minor corrections to Glob release date
+ 2021-01-08 54bd1ccce2 cmd: update to latest golang.org/x/tools
+ 2021-01-07 9ec21a8f34 Revert "reflect: support multiple keys in struct tags"
+ 2021-01-07 091414b5b7 io/fs: correct WalkDirFunc documentation
+ 2021-01-07 9b55088d6b doc/go1.16: add release note for disallowing non-ASCII import paths
+ 2021-01-07 fa90aaca7d cmd/compile: fix late expand_calls leaf type for OpStructSelect/OpArraySelect
+ 2021-01-07 7cee66d4cb cmd/go: add documentation for Embed fields in go list output
+ 2021-01-07 e60cffa4ca html/template: attach functions to namespace
+ 2021-01-07 6da2d3b7d7 cmd/link: fix typo in asm.go
+ 2021-01-07 df81a15819 runtime: check mips64 VDSO clock_gettime return code
+ 2021-01-06 4787e906cf crypto/x509: rollback new CertificateRequest fields
+ 2021-01-06 c9658bee93 cmd/go: make module suggestion more friendly
+ 2021-01-06 4c668b25c6 runtime/metrics: fix panic message for Float64Histogram
+ 2021-01-06 d2131704a6 net/http/httputil: fix deadlock in DumpRequestOut
+ 2021-01-05 3e1e13ce6d cmd/go: set cfg.BuildMod to "readonly" by default with no module root
+ 2021-01-05 0b0d004983 cmd/go: pass embedcfg to gccgo if supported
+ 2021-01-05 1b85e7c057 cmd/go: don't scan gccgo standard library packages for imports
+ 2021-01-05 6b37b15d95 runtime: don't take allglock in tracebackothers
+ 2021-01-04 9eef49cfa6 math/rand: fix typo in comment
+ 2021-01-04 b01fb2af9e testing/fstest: fix typo in error message
+ 2021-01-01 3dd5867605 doc: 2021 is the Year of the Gopher
+ 2020-12-31 95ce805d14 io/fs: remove darwin/arm64 special condition
+ 2020-12-30 20d0991b86 lib/time, time/tzdata: update tzdata to 2020f
+ 2020-12-30 ed301733bb misc/cgo/testcarchive: remove special flags for Darwin/ARM
+ 2020-12-30 0ae2e032f2 misc/cgo/test: enable TestCrossPackageTests on darwin/arm64
+ 2020-12-29 780b4de16b misc/ios: fix wording for command line instructions
+ 2020-12-29 b4a71c95d2 doc/go1.16: reference misc/ios/README for how to build iOS programs
+ 2020-12-29 f83e0f6616 misc/ios: add to README how to build ios executables
+ 2020-12-28 4fd9455882 io/fs: fix typo in comment

Change-Id: If24bb93f1e1e7deb1d92ba223c85940ab93b2732

3 files changed, 426 insertions, 1 deletions

diff --git a/src/cmd/compile/internal/test/abiutils_test.go b/src/cmd/compile/internal/test/abiutils_test.go
new file mode 100644
index 0000000000..ae7d484062
--- /dev/null
+++ b/src/cmd/compile/internal/test/abiutils_test.go
@@ -0,0 +1,269 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package test
+
+import (
+	"bufio"
+	"cmd/compile/internal/abi"
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ssagen"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/internal/obj"
+	"cmd/internal/obj/x86"
+	"cmd/internal/src"
+	"os"
+	"testing"
+)
+
+// AMD64 registers available:
+// - integer: RAX, RBX, RCX, RDI, RSI, R8, R9, r10, R11
+// - floating point: X0 - X14
+var configAMD64 = abi.NewABIConfig(9,15)
+
+func TestMain(m *testing.M) {
+	ssagen.Arch.LinkArch = &x86.Linkamd64
+	ssagen.Arch.REGSP = x86.REGSP
+	ssagen.Arch.MAXWIDTH = 1 << 50
+	types.MaxWidth = ssagen.Arch.MAXWIDTH
+	base.Ctxt = obj.Linknew(ssagen.Arch.LinkArch)
+	base.Ctxt.DiagFunc = base.Errorf
+	base.Ctxt.DiagFlush = base.FlushErrors
+	base.Ctxt.Bso = bufio.NewWriter(os.Stdout)
+	types.PtrSize = ssagen.Arch.LinkArch.PtrSize
+	types.RegSize = ssagen.Arch.LinkArch.RegSize
+	typecheck.InitUniverse()
+	os.Exit(m.Run())
+}
+
+func TestABIUtilsBasic1(t *testing.T) {
+
+	// func(x int32) int32
+	i32 := types.Types[types.TINT32]
+	ft := mkFuncType(nil, []*types.Type{i32}, []*types.Type{i32})
+
+	// expected results
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 } offset: -1 typ: int32
+		OUT 0: R{ I0 } offset: -1 typ: int32
+		intspill: 1 floatspill: 0 offsetToSpillArea: 0
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsBasic2(t *testing.T) {
+	// func(x int32, y float64) (int32, float64, float64)
+	i8 := types.Types[types.TINT8]
+	i16 := types.Types[types.TINT16]
+	i32 := types.Types[types.TINT32]
+	i64 := types.Types[types.TINT64]
+	f32 := types.Types[types.TFLOAT32]
+	f64 := types.Types[types.TFLOAT64]
+	c64 := types.Types[types.TCOMPLEX64]
+	c128 := types.Types[types.TCOMPLEX128]
+	ft := mkFuncType(nil,
+		[]*types.Type{
+			i8, i16, i32, i64,
+			f32, f32, f64, f64,
+			i8, i16, i32, i64,
+			f32, f32, f64, f64,
+			c128, c128, c128, c128, c64,
+			i8, i16, i32, i64,
+			i8, i16, i32, i64},
+		[]*types.Type{i32, f64, f64})
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 } offset: -1 typ: int8
+		IN 1: R{ I1 } offset: -1 typ: int16
+		IN 2: R{ I2 } offset: -1 typ: int32
+		IN 3: R{ I3 } offset: -1 typ: int64
+		IN 4: R{ F0 } offset: -1 typ: float32
+		IN 5: R{ F1 } offset: -1 typ: float32
+		IN 6: R{ F2 } offset: -1 typ: float64
+		IN 7: R{ F3 } offset: -1 typ: float64
+		IN 8: R{ I4 } offset: -1 typ: int8
+		IN 9: R{ I5 } offset: -1 typ: int16
+		IN 10: R{ I6 } offset: -1 typ: int32
+		IN 11: R{ I7 } offset: -1 typ: int64
+		IN 12: R{ F4 } offset: -1 typ: float32
+		IN 13: R{ F5 } offset: -1 typ: float32
+		IN 14: R{ F6 } offset: -1 typ: float64
+		IN 15: R{ F7 } offset: -1 typ: float64
+		IN 16: R{ F8 F9 } offset: -1 typ: complex128
+		IN 17: R{ F10 F11 } offset: -1 typ: complex128
+		IN 18: R{ F12 F13 } offset: -1 typ: complex128
+		IN 19: R{ } offset: 0 typ: complex128
+		IN 20: R{ F14 } offset: -1 typ: complex64
+		IN 21: R{ I8 } offset: -1 typ: int8
+		IN 22: R{ } offset: 16 typ: int16
+		IN 23: R{ } offset: 20 typ: int32
+		IN 24: R{ } offset: 24 typ: int64
+		IN 25: R{ } offset: 32 typ: int8
+		IN 26: R{ } offset: 34 typ: int16
+		IN 27: R{ } offset: 36 typ: int32
+		IN 28: R{ } offset: 40 typ: int64
+		OUT 0: R{ I0 } offset: -1 typ: int32
+		OUT 1: R{ F0 } offset: -1 typ: float64
+		OUT 2: R{ F1 } offset: -1 typ: float64
+		intspill: 9 floatspill: 15 offsetToSpillArea: 48
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsArrays(t *testing.T) {
+	i32 := types.Types[types.TINT32]
+	ae := types.NewArray(i32, 0)
+	a1 := types.NewArray(i32, 1)
+	a2 := types.NewArray(i32, 2)
+	aa1 := types.NewArray(a1, 1)
+	ft := mkFuncType(nil, []*types.Type{a1, ae, aa1, a2},
+		[]*types.Type{a2, a1, ae, aa1})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 } offset: -1 typ: [1]int32
+		IN 1: R{ } offset: 0 typ: [0]int32
+		IN 2: R{ I1 } offset: -1 typ: [1][1]int32
+		IN 3: R{ } offset: 0 typ: [2]int32
+		OUT 0: R{ } offset: 8 typ: [2]int32
+		OUT 1: R{ I0 } offset: -1 typ: [1]int32
+		OUT 2: R{ } offset: 16 typ: [0]int32
+		OUT 3: R{ I1 } offset: -1 typ: [1][1]int32
+		intspill: 2 floatspill: 0 offsetToSpillArea: 16
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsStruct1(t *testing.T) {
+	i8 := types.Types[types.TINT8]
+	i16 := types.Types[types.TINT16]
+	i32 := types.Types[types.TINT32]
+	i64 := types.Types[types.TINT64]
+	s := mkstruct([]*types.Type{i8, i8, mkstruct([]*types.Type{}), i8, i16})
+	ft := mkFuncType(nil, []*types.Type{i8, s, i64},
+		[]*types.Type{s, i8, i32})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 } offset: -1 typ: int8
+		IN 1: R{ I1 I2 I3 I4 } offset: -1 typ: struct { int8; int8; struct {}; int8; int16 }
+		IN 2: R{ I5 } offset: -1 typ: int64
+		OUT 0: R{ I0 I1 I2 I3 } offset: -1 typ: struct { int8; int8; struct {}; int8; int16 }
+		OUT 1: R{ I4 } offset: -1 typ: int8
+		OUT 2: R{ I5 } offset: -1 typ: int32
+		intspill: 6 floatspill: 0 offsetToSpillArea: 0
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsStruct2(t *testing.T) {
+	f64 := types.Types[types.TFLOAT64]
+	i64 := types.Types[types.TINT64]
+	s := mkstruct([]*types.Type{i64, mkstruct([]*types.Type{})})
+	fs := mkstruct([]*types.Type{f64, s, mkstruct([]*types.Type{})})
+	ft := mkFuncType(nil, []*types.Type{s, s, fs},
+		[]*types.Type{fs, fs})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 } offset: -1 typ: struct { int64; struct {} }
+		IN 1: R{ I1 } offset: -1 typ: struct { int64; struct {} }
+		IN 2: R{ I2 F0 } offset: -1 typ: struct { float64; struct { int64; struct {} }; struct {} }
+		OUT 0: R{ I0 F0 } offset: -1 typ: struct { float64; struct { int64; struct {} }; struct {} }
+		OUT 1: R{ I1 F1 } offset: -1 typ: struct { float64; struct { int64; struct {} }; struct {} }
+		intspill: 3 floatspill: 1 offsetToSpillArea: 0
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsSliceString(t *testing.T) {
+	i32 := types.Types[types.TINT32]
+	sli32 := types.NewSlice(i32)
+	str := types.New(types.TSTRING)
+	i8 := types.Types[types.TINT8]
+	i64 := types.Types[types.TINT64]
+	ft := mkFuncType(nil, []*types.Type{sli32, i8, sli32, i8, str, i8, i64, sli32},
+		[]*types.Type{str, i64, str, sli32})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 I1 I2 } offset: -1 typ: []int32
+		IN 1: R{ I3 } offset: -1 typ: int8
+		IN 2: R{ I4 I5 I6 } offset: -1 typ: []int32
+		IN 3: R{ I7 } offset: -1 typ: int8
+		IN 4: R{ } offset: 0 typ: string
+		IN 5: R{ I8 } offset: -1 typ: int8
+		IN 6: R{ } offset: 16 typ: int64
+		IN 7: R{ } offset: 24 typ: []int32
+		OUT 0: R{ I0 I1 } offset: -1 typ: string
+		OUT 1: R{ I2 } offset: -1 typ: int64
+		OUT 2: R{ I3 I4 } offset: -1 typ: string
+		OUT 3: R{ I5 I6 I7 } offset: -1 typ: []int32
+		intspill: 9 floatspill: 0 offsetToSpillArea: 48
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsMethod(t *testing.T) {
+	i16 := types.Types[types.TINT16]
+	i64 := types.Types[types.TINT64]
+	f64 := types.Types[types.TFLOAT64]
+
+	s1 := mkstruct([]*types.Type{i16, i16, i16})
+	ps1 := types.NewPtr(s1)
+	a7 := types.NewArray(ps1, 7)
+	ft := mkFuncType(s1, []*types.Type{ps1, a7, f64, i16, i16, i16},
+		[]*types.Type{a7, f64, i64})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 I1 I2 } offset: -1 typ: struct { int16; int16; int16 }
+		IN 1: R{ I3 } offset: -1 typ: *struct { int16; int16; int16 }
+		IN 2: R{ } offset: 0 typ: [7]*struct { int16; int16; int16 }
+		IN 3: R{ F0 } offset: -1 typ: float64
+		IN 4: R{ I4 } offset: -1 typ: int16
+		IN 5: R{ I5 } offset: -1 typ: int16
+		IN 6: R{ I6 } offset: -1 typ: int16
+		OUT 0: R{ } offset: 56 typ: [7]*struct { int16; int16; int16 }
+		OUT 1: R{ F0 } offset: -1 typ: float64
+		OUT 2: R{ I0 } offset: -1 typ: int64
+		intspill: 7 floatspill: 1 offsetToSpillArea: 112
+`)
+
+	abitest(t, ft, exp)
+}
+
+func TestABIUtilsInterfaces(t *testing.T) {
+	ei := types.Types[types.TINTER] // interface{}
+	pei := types.NewPtr(ei)         // *interface{}
+	fldt := mkFuncType(types.FakeRecvType(), []*types.Type{},
+		[]*types.Type{types.UntypedString})
+	field := types.NewField(src.NoXPos, nil, fldt)
+	// interface{ ...() string }
+	nei := types.NewInterface(types.LocalPkg, []*types.Field{field})
+
+	i16 := types.Types[types.TINT16]
+	tb := types.Types[types.TBOOL]
+	s1 := mkstruct([]*types.Type{i16, i16, tb})
+
+	ft := mkFuncType(nil, []*types.Type{s1, ei, ei, nei, pei, nei, i16},
+		[]*types.Type{ei, nei, pei})
+
+	exp := makeExpectedDump(`
+		IN 0: R{ I0 I1 I2 } offset: -1 typ: struct { int16; int16; bool }
+		IN 1: R{ I3 I4 } offset: -1 typ: interface {}
+		IN 2: R{ I5 I6 } offset: -1 typ: interface {}
+		IN 3: R{ I7 I8 } offset: -1 typ: interface { () untyped string }
+		IN 4: R{ } offset: 0 typ: *interface {}
+		IN 5: R{ } offset: 8 typ: interface { () untyped string }
+		IN 6: R{ } offset: 24 typ: int16
+		OUT 0: R{ I0 I1 } offset: -1 typ: interface {}
+		OUT 1: R{ I2 I3 } offset: -1 typ: interface { () untyped string }
+		OUT 2: R{ I4 } offset: -1 typ: *interface {}
+		intspill: 9 floatspill: 0 offsetToSpillArea: 32
+`)
+
+	abitest(t, ft, exp)
+}
diff --git a/src/cmd/compile/internal/test/abiutilsaux_test.go b/src/cmd/compile/internal/test/abiutilsaux_test.go
new file mode 100644
index 0000000000..10fb668745
--- /dev/null
+++ b/src/cmd/compile/internal/test/abiutilsaux_test.go
@@ -0,0 +1,156 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package test
+
+// This file contains utility routines and harness infrastructure used
+// by the ABI tests in "abiutils_test.go".
+
+import (
+	"cmd/compile/internal/abi"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+	"fmt"
+	"strings"
+	"testing"
+	"text/scanner"
+)
+
+func mkParamResultField(t *types.Type, s *types.Sym, which ir.Class) *types.Field {
+	field := types.NewField(src.NoXPos, s, t)
+	n := typecheck.NewName(s)
+	n.Class = which
+	field.Nname = n
+	n.SetType(t)
+	return field
+}
+
+// mkstruct is a helper routine to create a struct type with fields
+// of the types specified in 'fieldtypes'.
+func mkstruct(fieldtypes []*types.Type) *types.Type {
+	fields := make([]*types.Field, len(fieldtypes))
+	for k, t := range fieldtypes {
+		if t == nil {
+			panic("bad -- field has no type")
+		}
+		f := types.NewField(src.NoXPos, nil, t)
+		fields[k] = f
+	}
+	s := types.NewStruct(types.LocalPkg, fields)
+	return s
+}
+
+func mkFuncType(rcvr *types.Type, ins []*types.Type, outs []*types.Type) *types.Type {
+	q := typecheck.Lookup("?")
+	inf := []*types.Field{}
+	for _, it := range ins {
+		inf = append(inf, mkParamResultField(it, q, ir.PPARAM))
+	}
+	outf := []*types.Field{}
+	for _, ot := range outs {
+		outf = append(outf, mkParamResultField(ot, q, ir.PPARAMOUT))
+	}
+	var rf *types.Field
+	if rcvr != nil {
+		rf = mkParamResultField(rcvr, q, ir.PPARAM)
+	}
+	return types.NewSignature(types.LocalPkg, rf, inf, outf)
+}
+
+type expectedDump struct {
+	dump string
+	file string
+	line int
+}
+
+func tokenize(src string) []string {
+	var s scanner.Scanner
+	s.Init(strings.NewReader(src))
+	res := []string{}
+	for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
+		res = append(res, s.TokenText())
+	}
+	return res
+}
+
+func verifyParamResultOffset(t *testing.T, f *types.Field, r abi.ABIParamAssignment, which string, idx int) int {
+	n := ir.AsNode(f.Nname).(*ir.Name)
+	if n.FrameOffset() != int64(r.Offset) {
+		t.Errorf("%s %d: got offset %d wanted %d t=%v",
+			which, idx, r.Offset, n.Offset_, f.Type)
+		return 1
+	}
+	return 0
+}
+
+func makeExpectedDump(e string) expectedDump {
+	return expectedDump{dump: e}
+}
+
+func difftokens(atoks []string, etoks []string) string {
+	if len(atoks) != len(etoks) {
+		return fmt.Sprintf("expected %d tokens got %d",
+			len(etoks), len(atoks))
+	}
+	for i := 0; i < len(etoks); i++ {
+		if etoks[i] == atoks[i] {
+			continue
+		}
+
+		return fmt.Sprintf("diff at token %d: expected %q got %q",
+			i, etoks[i], atoks[i])
+	}
+	return ""
+}
+
+func abitest(t *testing.T, ft *types.Type, exp expectedDump) {
+
+	types.CalcSize(ft)
+
+	// Analyze with full set of registers.
+	regRes := abi.ABIAnalyze(ft, configAMD64)
+	regResString := strings.TrimSpace(regRes.String())
+
+	// Check results.
+	reason := difftokens(tokenize(regResString), tokenize(exp.dump))
+	if reason != "" {
+		t.Errorf("\nexpected:\n%s\ngot:\n%s\nreason: %s",
+			strings.TrimSpace(exp.dump), regResString, reason)
+	}
+
+	// Analyze again with empty register set.
+	empty := &abi.ABIConfig{}
+	emptyRes := abi.ABIAnalyze(ft, empty)
+	emptyResString := emptyRes.String()
+
+	// Walk the results and make sure the offsets assigned match
+	// up with those assiged by CalcSize. This checks to make sure that
+	// when we have no available registers the ABI assignment degenerates
+	// back to the original ABI0.
+
+	// receiver
+	failed := 0
+	rfsl := ft.Recvs().Fields().Slice()
+	poff := 0
+	if len(rfsl) != 0 {
+		failed |= verifyParamResultOffset(t, rfsl[0], emptyRes.InParams()[0], "receiver", 0)
+		poff = 1
+	}
+	// params
+	pfsl := ft.Params().Fields().Slice()
+	for k, f := range pfsl {
+		verifyParamResultOffset(t, f, emptyRes.InParams()[k+poff], "param", k)
+	}
+	// results
+	ofsl := ft.Results().Fields().Slice()
+	for k, f := range ofsl {
+		failed |= verifyParamResultOffset(t, f, emptyRes.OutParams()[k], "result", k)
+	}
+
+	if failed != 0 {
+		t.Logf("emptyres:\n%s\n", emptyResString)
+	}
+}
diff --git a/src/cmd/compile/internal/test/testdata/reproducible/issue38068.go b/src/cmd/compile/internal/test/testdata/reproducible/issue38068.go
index db5ca7dcbe..b87daed8e9 100644
--- a/src/cmd/compile/internal/test/testdata/reproducible/issue38068.go
+++ b/src/cmd/compile/internal/test/testdata/reproducible/issue38068.go
@@ -53,7 +53,7 @@ func G(x *A, n int) {
 		return
 	}
 	// Address-taken local of type A, which will insure that the
-	// compiler's dtypesym() routine will create a method wrapper.
+	// compiler's writeType() routine will create a method wrapper.
 	var a, b A
 	a.next = x
 	a.prev = &b