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[dev.typeparams] Separate out gcshape types that are instantiated types

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Distinguish the gcshape of all top-level instantiated type from normal
concrete types, even if they have the exact same underlying "shape",
because in a function instantiation, any method call on this type arg
will be a generic method call (requiring a dictionary), rather than a
direct method call on the underlying type (no dictionary).

So, we add the instshape prefix to the gcshape name for instantiated
types, and we make it a defined type with that name.

Change-Id: I33056269d24f3451a2632a5ce6a481108f533c9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/335169
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Dan Scales 2021-07-09 16:27:22 -07:00
parent df778e6fd9
commit 9b85985d36
1 changed files with 27 additions and 1 deletions
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28
src/cmd/compile/internal/noder/stencil.go
View file

@ -729,11 +729,37 @@ func gcshapeType(t *types.Type) (*types.Type, string) {
// Call CallSize so type sizes and field offsets are available.
types.CalcSize(t)
instType := t.Sym() != nil && t.IsFullyInstantiated()
if instType {
// We distinguish the gcshape of all top-level instantiated type from
// normal concrete types, even if they have the exact same underlying
// "shape", because in a function instantiation, any method call on
// this type arg will be a generic method call (requiring a
// dictionary), rather than a direct method call on the underlying
// type (no dictionary). So, we add the instshape prefix to the
// normal gcshape name, and will make it a defined type with that
// name below.
buf.WriteString("instshape-")
}
fl = accumGcshape(fl, buf, t, nil)
// TODO: Should gcshapes be in a global package, so we don't have to
// duplicate in each package? Or at least in the specified source package
// of a function/method instantiation?
gcshape := types.NewStruct(types.LocalPkg, fl)
gcname := buf.String()
if instType {
// Lookup or create type with name 'gcname' (with instshape prefix).
newsym := t.Sym().Pkg.Lookup(gcname)
if newsym.Def != nil {
gcshape = newsym.Def.Type()
} else {
newt := typecheck.NewIncompleteNamedType(t.Pos(), newsym)
newt.SetUnderlying(gcshape.Underlying())
gcshape = newt
}
}
assert(gcshape.Size() == t.Size())
return gcshape, buf.String()
}
@ -764,7 +790,7 @@ func (g *irgen) getInstantiation(nameNode *ir.Name, targs []*types.Type, isMeth
// Testing out gcshapeType() and gcshapeName()
for i, t := range targs {
gct, gcs := gcshapeType(t)
fmt.Printf("targ %d: %v %v\n", i, gct, gcs)
fmt.Printf("targ %d: %v %v %v\n", i, gcs, gct, gct.Underlying())
}
}
// If instantiation doesn't exist yet, create it and add