all: REVERSE MERGE dev.unified (d558507) into master

This commit is a REVERSE MERGE.
It merges dev.unified back into its parent branch, master.
This marks the end of development on dev.unified.

Merge List:

+ 2022-08-04 d558507db4 [dev.unified] all: merge master (85d87b9) into dev.unified
+ 2022-08-03 c9f2150cfb [dev.unified] cmd/compile: start using runtime dictionaries
+ 2022-07-30 994ff78ba0 [dev.unified] go/internal: set underlying types in proper order
+ 2022-07-28 23554d4744 [dev.unified] all: merge master (462b78f) into dev.unified
+ 2022-07-28 c8d5ccf82e [dev.unified] go/internal/gcimporter: flatten imports
+ 2022-07-28 ac0844ec27 [dev.unified] cmd/compile: move "has init" to private metadata
+ 2022-07-28 f995946094 [dev.unified] cmd/compile: implement simple inline body pruning heuristic
+ 2022-07-28 f2851c67fd [dev.unified] cmd/compile: allow inlining to fail gracefully
+ 2022-07-28 831fdf1dff [dev.unified] cmd/compile: extract nil handling from exprType
+ 2022-07-28 92798176e7 [dev.unified] cmd/compile: write iface conversion RTTI into unified IR
+ 2022-07-28 9b70178d58 [dev.unified] cmd/compile: write RTTI into unified IR export data
+ 2022-07-25 fc72b7705d [dev.unified] cmd/compile: add method expressions to dictionaries
+ 2022-07-25 f48fa643f1 [dev.unified] cmd/compile: remove obsolete RTTI wiring
+ 2022-07-22 131f981df0 [dev.unified] cmd/compile: make Unified IR always writes concrete type for const exprs
+ 2022-07-20 ae43bdc3e3 Merge "[dev.unified] all: merge master (8e1e64c) into dev.unified" into dev.unified
+ 2022-07-19 7a8ba83b72 [dev.unified] cmd/compile/internal/reflectdata: remove hasRType's `required` param
+ 2022-07-19 64cd6faa13 [dev.unified] cmd/compile/internal/noder: simplify mixed tag/case RTTI wiring
+ 2022-07-19 a4c5198a3c [dev.unified] cmd/compile/internal/noder: better switch statements
+ 2022-07-19 318027044a [dev.unified] cmd/compile/internal/noder: explicit nil handling
+ 2022-07-19 e971b6a9be [dev.unified] test: add switch test case for tricky nil handling
+ 2022-07-19 878439cfe5 [dev.unified] cmd/compile/internal/noder: preserve RTTI for select statements
+ 2022-07-19 e376746e54 [dev.unified] cmd/compile/internal/noder: wire RTTI for implicit conversions
+ 2022-07-19 c846fd8e13 [dev.unified] cmd/compile/internal/noder: implicit conversions for binary exprs
+ 2022-07-19 ebd34e3e45 [dev.unified] test: relax panic message expectations
+ 2022-07-19 76a82f09d6 [dev.unified] cmd/compile/internal/noder: prefer *At functions
+ 2022-07-19 de649a2a98 [dev.unified] all: merge master (8e1e64c) into dev.unified
+ 2022-07-19 055a5e55fa [dev.unified] test: change Unicode file/package name to use characters not translated by macOS.
+ 2022-07-18 2cf632cd57 [dev.unified] cmd/compile/internal/reflectdata: prefer ITabAddrAt in ConvIfaceTypeWord
+ 2022-07-12 9371a65584 internal/pkgbits: change EnableSync into a dynamic knob
+ 2022-07-01 d667be8831 [dev.unified] cmd/compile/internal/walk: RType fields for range assignments
+ 2022-06-30 1b838e9556 [dev.unified] all: merge master (993c387) into dev.unified
+ 2022-06-30 0a503cf43a [dev.unified] cmd/compile: refactor `range` desugaring
+ 2022-06-30 3635b07d16 [dev.unified] cmd/compile/internal/noder: implicit conversions for multi-valued expressions
+ 2022-06-30 e7219cc093 [dev.unified] cmd/compile/internal/noder: refactor N:1 expression handling
+ 2022-06-30 2f3ef73e18 [dev.unified] test: tweak nilcheck test
+ 2022-06-30 95d7ce9ab1 [dev.unified] test: break escape_iface.go into unified/nounified variants
+ 2022-06-30 f751319a0b [dev.unified] test: relax live_regabi.go
+ 2022-06-30 e3cdc981c8 [dev.unified] cmd/compile/internal/walk: fix typo in debug print
+ 2022-06-29 2280d897d6 [dev.unified] test: add regress test for generic select statements
+ 2022-06-27 4b78ece3d7 [dev.unified] cmd/compile: drop package height from Unified IR importer
+ 2022-06-27 398d46d538 [dev.unified] cmd/compile/internal/types2: remove package height
+ 2022-06-24 e7100adbca [dev.unified] all: merge master (5a1c5b8) into dev.unified
+ 2022-06-23 09a838ad86 [dev.unified] cmd/compile: rename haveRType and implicitExpr
+ 2022-06-23 421e9e9db2 [dev.unified] cmd/compile: implicit conversions for return statements
+ 2022-06-23 a3fea7796a [dev.unified] cmd/compile/internal/noder: implicit conversions for writer.assignStmt
+ 2022-06-23 82a958a661 [dev.unified] cmd/compile/internal/noder: refactor stmtAssign generation
+ 2022-06-23 711dacd8cf [dev.unified] cmd/compile/internal/noder: implicit conversion of call arguments
+ 2022-06-23 46b01ec667 [dev.unified] cmd/compile/internal/noder: remove needType logic
+ 2022-06-23 a3e474f867 [dev.unified] cmd/compile/internal/noder: implicit conversions for complits
+ 2022-06-23 5f5422a2dd [dev.unified] cmd/compile/internal/noder: start writing implicit conversions
+ 2022-06-23 9cb784ac69 [dev.unified] cmd/compile/internal/noder: add pkgWriter.typeOf helper
+ 2022-06-23 c70e93ff3d [dev.unified] cmd/compile/internal/typecheck: replace unreachable code with assert
+ 2022-06-23 20e1d5ac8c [dev.unified] cmd/compile: special case f(g()) calls in Unified IR
+ 2022-06-23 61ae2b734c [dev.unified] cmd/compile: plumb rtype through OSWITCH/OCASE clauses
+ 2022-06-23 3d432b6c4b [dev.unified] cmd/compile: plumb rtype through for OMAPLIT
+ 2022-06-23 7368647ac6 [dev.unified] cmd/compile: start setting RType fields for Unified IR
+ 2022-06-23 5960f4ec10 [dev.unified] cmd/compile: add RType fields
+ 2022-06-21 5e0258c700 [dev.unified] cmd/compile: avoid reflectType in ssagen
+ 2022-06-21 93833cd5d8 [dev.unified] cmd/compile: extract rtype code from walk
+ 2022-06-21 f70775ff22 [dev.unified] cmd/compile: refactor reflectdata.{TypePtr,ITabAddr}
+ 2022-06-21 fc5dad6646 [dev.unified] cmd/compile/internal/walk: minor prep refactoring
+ 2022-06-16 1f4e8afafe [dev.unified] all: merge master (635b124) into dev.unified
+ 2022-06-15 8a9485c023 [dev.unified] test: extract different inline test between unified and non-unified
+ 2022-06-14 394ea70cc9 [dev.unified] cmd/compile: more Unified IR docs and review
+ 2022-06-10 f73ad3d24d [dev.unified] test: add regress tests for #53276 and #53328
+ 2022-06-09 8ef8b60e18 [dev.unified] cmd/compile/internal/noder: stop handling type expressions as expressions
+ 2022-06-09 1a6c96bb9b [dev.unified] test: relax issue7921.go diagnostic message
+ 2022-06-09 c50c6bbc03 [dev.unified] cmd/compile: set base.Pos when process assignDef in Unified IR
+ 2022-06-09 d6df08693c [dev.unified] cmd/compile: fix unified IR don't report type size too large error
+ 2022-06-08 e7ef58542c [dev.unified] cmd/compile: restore Unified IR linkname pragma diagnostic
+ 2022-06-07 9e5c968021 [dev.unified] cmd/compile: visit LHS before RHS/X in assign/for statement
+ 2022-06-06 46ddf0873e [dev.unified] cmd/compile: export/import implicit attribute for conversion exprs
+ 2022-06-06 a8780f94c3 [dev.unified] cmd/compile: fix missing method value wrapper in unified IR
+ 2022-06-06 3a1f1e1575 [dev.unified] cmd/compile: remove package height
+ 2022-06-06 df7cb59de4 [dev.unified] cmd/compile: only sort symbols by name and package path
+ 2022-06-06 b39ac80871 [dev.unified] cmd/compile/internal/noder: push exprBlank up into assignment handling
+ 2022-06-06 55fc07e164 [dev.unified] cmd/compile/internal/noder: add optExpr for optional expressions
+ 2022-06-06 6c33f1d52e [dev.unified] cmd/compile/internal/noder: rename exprName to exprGlobal
+ 2022-06-06 4d28fcabb4 [dev.unified] all: update codereview.cfg for dev.unified branch

Change-Id: I604d057735e8a365621c91c206f9e46eabb4679b

1 files changed, 85 insertions, 22 deletions

diff --git a/src/cmd/compile/internal/noder/linker.go b/src/cmd/compile/internal/noder/linker.go
index a58b9b930c..0f39fdec05 100644
--- a/src/cmd/compile/internal/noder/linker.go
+++ b/src/cmd/compile/internal/noder/linker.go
@@ -1,5 +1,3 @@
-// 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.
@@ -34,13 +32,20 @@ import (
 // low-level linking details can be moved there, but the logic for
 // handling extension data needs to stay in the compiler.
 
+// A linker combines a package's stub export data with any referenced
+// elements from imported packages into a single, self-contained
+// export data file.
 type linker struct {
 	pw pkgbits.PkgEncoder
 
-	pkgs  map[string]pkgbits.Index
-	decls map[*types.Sym]pkgbits.Index
+	pkgs   map[string]pkgbits.Index
+	decls  map[*types.Sym]pkgbits.Index
+	bodies map[*types.Sym]pkgbits.Index
 }
 
+// relocAll ensures that all elements specified by pr and relocs are
+// copied into the output export data file, and returns the
+// corresponding indices in the output.
 func (l *linker) relocAll(pr *pkgReader, relocs []pkgbits.RelocEnt) []pkgbits.RelocEnt {
 	res := make([]pkgbits.RelocEnt, len(relocs))
 	for i, rent := range relocs {
@@ -50,6 +55,8 @@ func (l *linker) relocAll(pr *pkgReader, relocs []pkgbits.RelocEnt) []pkgbits.Re
 	return res
 }
 
+// relocIdx ensures a single element is copied into the output export
+// data file, and returns the corresponding index in the output.
 func (l *linker) relocIdx(pr *pkgReader, k pkgbits.RelocKind, idx pkgbits.Index) pkgbits.Index {
 	assert(pr != nil)
 
@@ -85,10 +92,19 @@ func (l *linker) relocIdx(pr *pkgReader, k pkgbits.RelocKind, idx pkgbits.Index)
 	return newidx
 }
 
+// relocString copies the specified string from pr into the output
+// export data file, deduplicating it against other strings.
 func (l *linker) relocString(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	return l.pw.StringIdx(pr.StringIdx(idx))
 }
 
+// relocPkg copies the specified package from pr into the output
+// export data file, rewriting its import path to match how it was
+// imported.
+//
+// TODO(mdempsky): Since CL 391014, we already have the compilation
+// unit's import path, so there should be no need to rewrite packages
+// anymore.
 func (l *linker) relocPkg(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	path := pr.PeekPkgPath(idx)
 
@@ -114,6 +130,9 @@ func (l *linker) relocPkg(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	return w.Flush()
 }
 
+// relocObj copies the specified object from pr into the output export
+// data file, rewriting its compiler-private extension data (e.g.,
+// adding inlining cost and escape analysis results for functions).
 func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	path, name, tag := pr.PeekObj(idx)
 	sym := types.NewPkg(path, "").Lookup(name)
@@ -152,21 +171,12 @@ func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	l.relocCommon(pr, &wname, pkgbits.RelocName, idx)
 	l.relocCommon(pr, &wdict, pkgbits.RelocObjDict, idx)
 
-	var obj *ir.Name
-	if sym.Pkg == types.LocalPkg {
-		var ok bool
-		obj, ok = sym.Def.(*ir.Name)
-
-		// Generic types and functions and declared constraint types won't
-		// have definitions.
-		// For now, just generically copy their extension data.
-		// TODO(mdempsky): Restore assertion.
-		if !ok && false {
-			base.Fatalf("missing definition for %v", sym)
-		}
-	}
+	// Generic types and functions won't have definitions, and imported
+	// objects may not either.
+	obj, _ := sym.Def.(*ir.Name)
+	local := sym.Pkg == types.LocalPkg
 
-	if obj != nil {
+	if local && obj != nil {
 		wext.Sync(pkgbits.SyncObject1)
 		switch tag {
 		case pkgbits.ObjFunc:
@@ -181,9 +191,66 @@ func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 		l.relocCommon(pr, &wext, pkgbits.RelocObjExt, idx)
 	}
 
+	// Check if we need to export the inline bodies for functions and
+	// methods.
+	if obj != nil {
+		if obj.Op() == ir.ONAME && obj.Class == ir.PFUNC {
+			l.exportBody(obj, local)
+		}
+
+		if obj.Op() == ir.OTYPE {
+			if typ := obj.Type(); !typ.IsInterface() {
+				for _, method := range typ.Methods().Slice() {
+					l.exportBody(method.Nname.(*ir.Name), local)
+				}
+			}
+		}
+	}
+
 	return w.Idx
 }
 
+// exportBody exports the given function or method's body, if
+// appropriate. local indicates whether it's a local function or
+// method available on a locally declared type. (Due to cross-package
+// type aliases, a method may be imported, but still available on a
+// locally declared type.)
+func (l *linker) exportBody(obj *ir.Name, local bool) {
+	assert(obj.Op() == ir.ONAME && obj.Class == ir.PFUNC)
+
+	fn := obj.Func
+	if fn.Inl == nil {
+		return // not inlinable anyway
+	}
+
+	// As a simple heuristic, if the function was declared in this
+	// package or we inlined it somewhere in this package, then we'll
+	// (re)export the function body. This isn't perfect, but seems
+	// reasonable in practice. In particular, it has the nice property
+	// that in the worst case, adding a blank import ensures the
+	// function body is available for inlining.
+	//
+	// TODO(mdempsky): Reimplement the reachable method crawling logic
+	// from typecheck/crawler.go.
+	exportBody := local || fn.Inl.Body != nil
+	if !exportBody {
+		return
+	}
+
+	sym := obj.Sym()
+	if _, ok := l.bodies[sym]; ok {
+		// Due to type aliases, we might visit methods multiple times.
+		base.AssertfAt(obj.Type().Recv() != nil, obj.Pos(), "expected method: %v", obj)
+		return
+	}
+
+	pri, ok := bodyReaderFor(fn)
+	assert(ok)
+	l.bodies[sym] = l.relocIdx(pri.pr, pkgbits.RelocBody, pri.idx)
+}
+
+// relocCommon copies the specified element from pr into w,
+// recursively relocating any referenced elements as well.
 func (l *linker) relocCommon(pr *pkgReader, w *pkgbits.Encoder, k pkgbits.RelocKind, idx pkgbits.Index) {
 	r := pr.NewDecoderRaw(k, idx)
 	w.Relocs = l.relocAll(pr, r.Relocs)
@@ -220,10 +287,6 @@ func (l *linker) relocFuncExt(w *pkgbits.Encoder, name *ir.Name) {
 	if inl := name.Func.Inl; w.Bool(inl != nil) {
 		w.Len(int(inl.Cost))
 		w.Bool(inl.CanDelayResults)
-
-		pri, ok := bodyReader[name.Func]
-		assert(ok)
-		w.Reloc(pkgbits.RelocBody, l.relocIdx(pri.pr, pkgbits.RelocBody, pri.idx))
 	}
 
 	w.Sync(pkgbits.SyncEOF)