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go/src/cmd/compile/internal/noder/sync.go

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[dev.typeparams] cmd/compile: unified IR construction This CL adds a new unified IR construction mode to the frontend. It's purely additive, and all files include "UNREVIEWED" at the top, like how types2 was initially imported. The next CL adds a -d=unified flag to actually enable unified IR mode. See below for more details, but some highlights: 1. It adds ~6kloc (excluding enum listings and stringer output), but I estimate it will allow removing ~14kloc (see CL 324670, including its commit message); 2. When enabled by default, it passes more tests than -G=3 does (see CL 325213 and CL 324673); 3. Without requiring any new code, it supports inlining of more code than the current inliner (see CL 324574; contrast CL 283112 and CL 266203, which added support for inlining function literals and type switches, respectively); 4. Aside from dictionaries (which I intend to add still), its support for generics is more complete (e.g., it fully supports local types, including local generic types within generic functions and instantiating generic types with local types; see test/typeparam/nested.go); 5. It supports lazy loading of types and objects for types2 type checking; 6. It supports re-exporting of types, objects, and inline bodies without needing to parse them into IR; 7. The new export data format has extensive support for debugging with "sync" markers, so mistakes during development are easier to catch; 8. When compiling with -d=inlfuncswithclosures=0, it enables "quirks mode" where it generates output that passes toolstash -cmp. -- The new unified IR pipeline combines noding, stenciling, inlining, and import/export into a single, shared code path. Previously, IR trees went through multiple phases of copying during compilation: 1. "Noding": the syntax AST is copied into the initial IR form. To support generics, there's now also "irgen", which implements the same idea, but takes advantage of types2 type-checking results to more directly construct IR. 2. "Stenciling": generic IR forms are copied into instantiated IR forms, substituting type parameters as appropriate. 3. "Inlining": the inliner made backup copies of inlinable functions, and then copied them again when inlining into a call site, with some modifications (e.g., updating position information, rewriting variable references, changing "return" statements into "goto"). 4. "Importing/exporting": the exporter wrote out the IR as saved by the inliner, and then the importer read it back as to be used by the inliner again. Normal functions are imported/exported "desugared", while generic functions are imported/exported in source form. These passes are all conceptually the same thing: make a copy of a function body, maybe with some minor changes/substitutions. However, they're all completely separate implementations that frequently run into the same issues because IR has many nuanced corner cases. For example, inlining currently doesn't support local defined types, "range" loops, or labeled "for"/"switch" statements, because these require special handling around Sym references. We've recently extended the inliner to support new features like inlining type switches and function literals, and they've had issues. The exporter only knows how to export from IR form, so when re-exporting inlinable functions (e.g., methods on imported types that are exposed via exported APIs), these functions may need to be imported as IR for the sole purpose of being immediately exported back out again. By unifying all of these modes of copying into a single code path that cleanly separates concerns, we eliminate many of these possible issues. Some recent examples: 1. Issues #45743 and #46472 were issues where type switches were mishandled by inlining and stenciling, respectively; but neither of these affected unified IR, because it constructs type switches using the exact same code as for normal functions. 2. CL 325409 fixes an issue in stenciling with implicit conversion of values of type-parameter type to variables of interface type, but this issue did not affect unified IR. Change-Id: I5a05991fe16d68bb0f712503e034cb9f2d19e296 Reviewed-on: https://go-review.googlesource.com/c/go/+/324573 Trust: Matthew Dempsky <mdempsky@google.com> Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
2021-05-13 20:23:13 -07:00
// UNREVIEWED
// Copyright 2021 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 noder
const debug = true
type syncMarker int
//go:generate stringer -type=syncMarker -trimprefix=sync
// TODO(mdempsky): Cleanup unneeded sync markers.
// TODO(mdempsky): Split these markers into public/stable markers, and
// private ones. Also, trim unused ones.
const (
_ syncMarker = iota
syncNode
syncBool
syncInt64
syncUint64
syncString
syncPos
syncPkg
syncSym
syncSelector
syncKind
syncType
syncTypePkg
syncSignature
syncParam
syncOp
syncObject
syncExpr
syncStmt
syncDecl
syncConstDecl
syncFuncDecl
syncTypeDecl
syncVarDecl
syncPragma
syncValue
syncEOF
syncMethod
syncFuncBody
syncUse
syncUseObj
syncObjectIdx
syncTypeIdx
syncBOF
syncEntry
syncOpenScope
syncCloseScope
syncGlobal
syncLocal
syncDefine
syncDefLocal
syncUseLocal
syncDefGlobal
syncUseGlobal
syncTypeParams
syncUseLabel
syncDefLabel
syncFuncLit
syncCommonFunc
syncBodyRef
syncLinksymExt
syncHack
syncSetlineno
syncName
syncImportDecl
syncDeclNames
syncDeclName
syncExprList
syncExprs
syncWrapname
syncTypeExpr
syncTypeExprOrNil
syncChanDir
syncParams
syncCloseAnotherScope
syncSum
syncUnOp
syncBinOp
syncStructType
syncInterfaceType
syncPackname
syncEmbedded
syncStmts
syncStmtsFall
syncStmtFall
syncBlockStmt
syncIfStmt
syncForStmt
syncSwitchStmt
syncRangeStmt
syncCaseClause
syncCommClause
syncSelectStmt
syncDecls
syncLabeledStmt
syncCompLit
sync1
sync2
sync3
sync4
syncN
syncDefImplicit
syncUseName
syncUseObjLocal
syncAddLocal
syncBothSignature
syncSetUnderlying
syncLinkname
syncStmt1
syncStmtsEnd
syncDeclare
syncTopDecls
syncTopConstDecl
syncTopFuncDecl
syncTopTypeDecl
syncTopVarDecl
syncObject1
syncAddBody
syncLabel
syncFuncExt
syncMethExt
syncOptLabel
syncScalar
syncStmtDecls
syncDeclLocal
syncObjLocal
syncObjLocal1
syncDeclareLocal
syncPublic
syncPrivate
syncRelocs
syncReloc
syncUseReloc
syncVarExt
syncPkgDef
syncTypeExt
syncVal
syncCodeObj
syncPosBase
syncLocalIdent
syncTypeParamNames
syncTypeParamBounds
)
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