cmd/compile: update the export version for generics

Bump the export version to a new value iexportVersionGo1_18 (2). This
will give a better error message when old compilers/tools encounter the
new export format (that includes parameterized types and functions).

We are also making a breaking change in the format:
 - a 'kind' byte is added to constant values

Also updated tinter() to pass the implicit bit through during type
substitution.

Tested that all tests still pass if the iexportVersionCurrent is changed
back to 1 in typecheck/iexport.go, iimporter/iimport.go, and
gcimporter/iimport.go

Updates #47654

Change-Id: I1dbeb167a97f6c7e0b7e0c011d6bada5db312b36
Reviewed-on: https://go-review.googlesource.com/c/go/+/357049
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Trust: Dan Scales <danscales@google.com>

diff --git a/src/cmd/compile/internal/importer/iimport.go b/src/cmd/compile/internal/importer/iimport.go
index cbc78539fd7987fa224bfaa7a1213df53391bc93..d04ef5c34d25d468bb6fd30ac8cc3a3fc0f79112 100644 (file)
--- a/src/cmd/compile/internal/importer/iimport.go
+++ b/src/cmd/compile/internal/importer/iimport.go
@@ -43,12 +43,12 @@ func (r *intReader) uint64() uint64 {
 
 // Keep this in sync with constants in iexport.go.
 const (
-       iexportVersionGo1_11 = 0
-       iexportVersionPosCol = 1
-       // TODO: before release, change this back to 2.
-       iexportVersionGenerics = iexportVersionPosCol
+       iexportVersionGo1_11   = 0
+       iexportVersionPosCol   = 1
+       iexportVersionGenerics = 1 // probably change to 2 before release
+       iexportVersionGo1_18   = 2
 
-       iexportVersionCurrent = iexportVersionGenerics
+       iexportVersionCurrent = 2
 )
 
 type ident struct {
@@ -99,13 +99,9 @@ func ImportData(imports map[string]*types2.Package, data, path string) (pkg *typ
 
        version = int64(r.uint64())
        switch version {
-       case /* iexportVersionGenerics, */ iexportVersionPosCol, iexportVersionGo1_11:
+       case iexportVersionGo1_18, iexportVersionPosCol, iexportVersionGo1_11:
        default:
-               if version > iexportVersionGenerics {
-                       errorf("unstable iexport format version %d, just rebuild compiler and std library", version)
-               } else {
-                       errorf("unknown iexport format version %d", version)
-               }
+               errorf("unknown iexport format version %d", version)
        }
 
        sLen := int64(r.uint64())
@@ -374,7 +370,19 @@ func (r *importReader) obj(name string) {
                id := ident{r.currPkg.Name(), name}
                r.p.tparamIndex[id] = t
 
-               t.SetConstraint(r.typ())
+               var implicit bool
+               if r.p.exportVersion >= iexportVersionGo1_18 {
+                       implicit = r.bool()
+               }
+               constraint := r.typ()
+               if implicit {
+                       iface, _ := constraint.(*types2.Interface)
+                       if iface == nil {
+                               errorf("non-interface constraint marked implicit")
+                       }
+                       iface.MarkImplicit()
+               }
+               t.SetConstraint(constraint)
 
        case 'V':
                typ := r.typ()
@@ -392,6 +400,10 @@ func (r *importReader) declare(obj types2.Object) {
 
 func (r *importReader) value() (typ types2.Type, val constant.Value) {
        typ = r.typ()
+       if r.p.exportVersion >= iexportVersionGo1_18 {
+               // TODO: add support for using the kind
+               _ = constant.Kind(r.int64())
+       }
 
        switch b := typ.Underlying().(*types2.Basic); b.Info() & types2.IsConstType {
        case types2.IsBoolean:

diff --git a/src/cmd/compile/internal/typecheck/iexport.go b/src/cmd/compile/internal/typecheck/iexport.go
index 46865ba3fa29e1605d94d065323671b154e4be84..6057000a5da4489ceccbb73572dc30b05bdb2988 100644 (file)
--- a/src/cmd/compile/internal/typecheck/iexport.go
+++ b/src/cmd/compile/internal/typecheck/iexport.go
@@ -254,15 +254,16 @@ import (
 // Current indexed export format version. Increase with each format change.
 // 0: Go1.11 encoding
 // 1: added column details to Pos
-// 2: added information for generic function/types (currently unstable)
+// 2: added information for generic function/types.  The export of non-generic
+// functions/types remains largely backward-compatible.  Breaking changes include:
+//    - a 'kind' byte is added to constant values
 const (
-       iexportVersionGo1_11 = 0
-       iexportVersionPosCol = 1
-       // TODO: before release, change this back to 2.  Kept at previous version
-       // for now (for testing).
-       iexportVersionGenerics = iexportVersionPosCol
+       iexportVersionGo1_11   = 0
+       iexportVersionPosCol   = 1
+       iexportVersionGenerics = 1 // probably change to 2 before release
+       iexportVersionGo1_18   = 2
 
-       iexportVersionCurrent = iexportVersionGenerics
+       iexportVersionCurrent = 2
 )
 
 // predeclReserved is the number of type offsets reserved for types
@@ -561,6 +562,10 @@ func (p *iexporter) doDecl(n *ir.Name) {
                        // A typeparam has a name, and has a type bound rather
                        // than an underlying type.
                        w.pos(n.Pos())
+                       if iexportVersionCurrent >= iexportVersionGo1_18 {
+                               implicit := n.Type().Bound().IsImplicit()
+                               w.bool(implicit)
+                       }
                        w.typ(n.Type().Bound())
                        break
                }
@@ -1137,17 +1142,24 @@ func constTypeOf(typ *types.Type) constant.Kind {
 
 func (w *exportWriter) value(typ *types.Type, v constant.Value) {
        w.typ(typ)
+
+       if iexportVersionCurrent >= iexportVersionGo1_18 {
+               w.int64(int64(v.Kind()))
+       }
+
        var kind constant.Kind
        var valType *types.Type
 
        if typ.IsTypeParam() {
-               // A constant will have a TYPEPARAM type if it appears in a place
-               // where it must match that typeparam type (e.g. in a binary
-               // operation with a variable of that typeparam type). If so, then
-               // we must write out its actual constant kind as well, so its
-               // constant val can be read in properly during import.
                kind = v.Kind()
-               w.int64(int64(kind))
+               if iexportVersionCurrent < iexportVersionGo1_18 {
+                       // A constant will have a TYPEPARAM type if it appears in a place
+                       // where it must match that typeparam type (e.g. in a binary
+                       // operation with a variable of that typeparam type). If so, then
+                       // we must write out its actual constant kind as well, so its
+                       // constant val can be read in properly during import.
+                       w.int64(int64(kind))
+               }
 
                switch kind {
                case constant.Int:

diff --git a/src/cmd/compile/internal/typecheck/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go
index fcfadc146c5513dbbc7e8c3c1d54d93b4e624493..7c6c23e73714515a322c25c20c2672223d398236 100644 (file)
--- a/src/cmd/compile/internal/typecheck/iimport.go
+++ b/src/cmd/compile/internal/typecheck/iimport.go
@@ -118,13 +118,9 @@ func ReadImports(pkg *types.Pkg, data string) {
 
        version := ird.uint64()
        switch version {
-       case /* iexportVersionGenerics, */ iexportVersionPosCol, iexportVersionGo1_11:
+       case iexportVersionGo1_18, iexportVersionPosCol, iexportVersionGo1_11:
        default:
-               if version > iexportVersionGenerics {
-                       base.Errorf("import %q: unstable export format version %d, just recompile", pkg.Path, version)
-               } else {
-                       base.Errorf("import %q: unknown export format version %d", pkg.Path, version)
-               }
+               base.Errorf("import %q: unknown export format version %d", pkg.Path, version)
                base.ErrorExit()
        }
 
@@ -408,8 +404,15 @@ func (r *importReader) doDecl(sym *types.Sym) *ir.Name {
                sym.Def = nname
                nname.SetType(t)
                t.SetNod(nname)
-
-               t.SetBound(r.typ())
+               implicit := false
+               if r.p.exportVersion >= iexportVersionGo1_18 {
+                       implicit = r.bool()
+               }
+               bound := r.typ()
+               if implicit {
+                       bound.MarkImplicit()
+               }
+               t.SetBound(bound)
                return nname
 
        case 'V':
@@ -429,10 +432,17 @@ func (r *importReader) value(typ *types.Type) constant.Value {
        var kind constant.Kind
        var valType *types.Type
 
-       if typ.IsTypeParam() {
-               // If a constant had a typeparam type, then we wrote out its
-               // actual constant kind as well.
+       if r.p.exportVersion >= iexportVersionGo1_18 {
+               // TODO: add support for using the kind in the non-typeparam case.
                kind = constant.Kind(r.int64())
+       }
+
+       if typ.IsTypeParam() {
+               if r.p.exportVersion < iexportVersionGo1_18 {
+                       // If a constant had a typeparam type, then we wrote out its
+                       // actual constant kind as well.
+                       kind = constant.Kind(r.int64())
+               }
                switch kind {
                case constant.Int:
                        valType = types.Types[types.TINT64]

diff --git a/src/cmd/compile/internal/typecheck/subr.go b/src/cmd/compile/internal/typecheck/subr.go
index 9ebd8f1423aef3a105d9b83e5e108a3fd37d613f..96e120fe03a78578796f8dcd67f3a48ef8742472 100644 (file)
--- a/src/cmd/compile/internal/typecheck/subr.go
+++ b/src/cmd/compile/internal/typecheck/subr.go
@@ -1390,7 +1390,7 @@ func (ts *Tsubster) tinter(t *types.Type, force bool) *types.Type {
                }
        }
        if newfields != nil {
-               return types.NewInterface(t.Pkg(), newfields, false)
+               return types.NewInterface(t.Pkg(), newfields, t.IsImplicit())
        }
        return t
 }

diff --git a/src/cmd/compile/internal/types/type.go b/src/cmd/compile/internal/types/type.go
index ec17fe8704aac526cea6fd8e060bff4d768371d1..c3efbc9f0717789d305774b76dd19918542556f2 100644 (file)
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@@ -1884,6 +1884,12 @@ func (t *Type) IsImplicit() bool {
        return t.extra.(*Interface).implicit
 }
 
+// MarkImplicit marks the interface as implicit.
+func (t *Type) MarkImplicit() {
+       t.wantEtype(TINTER)
+       t.extra.(*Interface).implicit = true
+}
+
 // NewUnion returns a new union with the specified set of terms (types). If
 // tildes[i] is true, then terms[i] represents ~T, rather than just T.
 func NewUnion(terms []*Type, tildes []bool) *Type {

diff --git a/src/go/internal/gcimporter/iimport.go b/src/go/internal/gcimporter/iimport.go
index 0771fa3c2614bfeb76925ebc1763fa1b7244ba93..49ea64392a578de274eb1c249c625f3f8f74247f 100644 (file)
--- a/src/go/internal/gcimporter/iimport.go
+++ b/src/go/internal/gcimporter/iimport.go
@@ -44,12 +44,12 @@ func (r *intReader) uint64() uint64 {
 
 // Keep this in sync with constants in iexport.go.
 const (
-       iexportVersionGo1_11 = 0
-       iexportVersionPosCol = 1
-       // TODO: before release, change this back to 2.
-       iexportVersionGenerics = iexportVersionPosCol
+       iexportVersionGo1_11   = 0
+       iexportVersionPosCol   = 1
+       iexportVersionGenerics = 1 // probably change to 2 before release
+       iexportVersionGo1_18   = 2
 
-       iexportVersionCurrent = iexportVersionGenerics
+       iexportVersionCurrent = 2
 )
 
 type ident struct {
@@ -98,13 +98,9 @@ func iImportData(fset *token.FileSet, imports map[string]*types.Package, dataRea
 
        version = int64(r.uint64())
        switch version {
-       case /* iexportVersionGenerics, */ iexportVersionPosCol, iexportVersionGo1_11:
+       case iexportVersionGo1_18, iexportVersionPosCol, iexportVersionGo1_11:
        default:
-               if version > iexportVersionGenerics {
-                       errorf("unstable iexport format version %d, just rebuild compiler and std library", version)
-               } else {
-                       errorf("unknown iexport format version %d", version)
-               }
+               errorf("unknown iexport format version %d", version)
        }
 
        sLen := int64(r.uint64())
@@ -367,7 +363,19 @@ func (r *importReader) obj(name string) {
                id := ident{r.currPkg.Name(), name}
                r.p.tparamIndex[id] = t
 
-               t.SetConstraint(r.typ())
+               var implicit bool
+               if r.p.exportVersion >= iexportVersionGo1_18 {
+                       implicit = r.bool()
+               }
+               constraint := r.typ()
+               if implicit {
+                       iface, _ := constraint.(*types.Interface)
+                       if iface == nil {
+                               errorf("non-interface constraint marked implicit")
+                       }
+                       iface.MarkImplicit()
+               }
+               t.SetConstraint(constraint)
 
        case 'V':
                typ := r.typ()
@@ -385,6 +393,10 @@ func (r *importReader) declare(obj types.Object) {
 
 func (r *importReader) value() (typ types.Type, val constant.Value) {
        typ = r.typ()
+       if r.p.exportVersion >= iexportVersionGo1_18 {
+               // TODO: add support for using the kind
+               _ = constant.Kind(r.int64())
+       }
 
        switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
        case types.IsBoolean: