cmd/compile: use HaveInlineBody for unified IR

In go.dev/cl/419674 I added a mechanism to the inliner to allow
inlining to fail gracefully when a function body is missing, but I
missed we already have a mechanism for that: typecheck.HaveInlineBody.

This CL makes it overridable so that unified IR can plug in its
appropriate logic, like it does with the logic for building the
ir.InlinedCallExpr node.

While here, rename inline.NewInline to inline.InlineCall, because the
name "NewInline" is now a misnomer since we initialize it to oldInline
(now named oldInlineCall).

Change-Id: I4e65618d3725919f69e6f43cf409699d20fb797c
Reviewed-on: https://go-review.googlesource.com/c/go/+/427234
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>

1 files changed, 14 insertions, 8 deletions

diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index a34d5c924a..8270c403fe 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -3374,22 +3374,28 @@ func (r *reader) pkgObjs(target *ir.Package) []*ir.Name {
 
 // @@@ Inlining
 
+// unifiedHaveInlineBody reports whether we have the function body for
+// fn, so we can inline it.
+func unifiedHaveInlineBody(fn *ir.Func) bool {
+	if fn.Inl == nil {
+		return false
+	}
+
+	_, ok := bodyReaderFor(fn)
+	return ok
+}
+
 var inlgen = 0
 
-// InlineCall implements inline.NewInline by re-reading the function
+// unifiedInlineCall implements inline.NewInline by re-reading the function
 // body from its Unified IR export data.
-func InlineCall(call *ir.CallExpr, fn *ir.Func, inlIndex int) *ir.InlinedCallExpr {
+func unifiedInlineCall(call *ir.CallExpr, fn *ir.Func, inlIndex int) *ir.InlinedCallExpr {
 	// TODO(mdempsky): Turn callerfn into an explicit parameter.
 	callerfn := ir.CurFunc
 
 	pri, ok := bodyReaderFor(fn)
 	if !ok {
-		// TODO(mdempsky): Reconsider this diagnostic's wording, if it's
-		// to be included in Go 1.20.
-		if base.Flag.LowerM != 0 {
-			base.WarnfAt(call.Pos(), "cannot inline call to %v: missing inline body", fn)
-		}
-		return nil
+		base.FatalfAt(call.Pos(), "cannot inline call to %v: missing inline body", fn)
 	}
 
 	if fn.Inl.Body == nil {