cmd/compile: desugar ORECOVER during typecheck

This never belonged in escape analysis, but the non-unified generics
frontend didn't use typecheck. That frontend is gone, so now we can
desugar it earlier.

Change-Id: I70f34a851f27fce1133777c5eeca0f549fc60ede
Reviewed-on: https://go-review.googlesource.com/c/go/+/518958
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/escape/call.go

@@ -55,7 +55,7 @@ func (e *escape) callCommon(ks []hole, call ir.Node, init *ir.Nodes, wrapper *ir
 		ir.Dump("esc", call)
 		base.Fatalf("unexpected call op: %v", call.Op())
 
-	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER:
+	case ir.OCALLFUNC, ir.OCALLINTER:
 		call := call.(*ir.CallExpr)
 		typecheck.AssertFixedCall(call)
 
@@ -186,9 +186,8 @@ func (e *escape) callCommon(ks []hole, call ir.Node, init *ir.Nodes, wrapper *ir
 		argument(e.discardHole(), &call.X)
 		argument(e.discardHole(), &call.Y)
 
-	case ir.ODELETE, ir.OMAX, ir.OMIN, ir.OPRINT, ir.OPRINTN, ir.ORECOVER:
+	case ir.ODELETE, ir.OMAX, ir.OMIN, ir.OPRINT, ir.OPRINTN, ir.ORECOVERFP:
 		call := call.(*ir.CallExpr)
-		fixRecoverCall(call)
 		for i := range call.Args {
 			argument(e.discardHole(), &call.Args[i])
 		}

src/cmd/compile/internal/escape/desugar.go

@@ -1,37 +0,0 @@
-// 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 escape
-
-import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/typecheck"
-	"cmd/compile/internal/types"
-)
-
-// TODO(mdempsky): Desugaring doesn't belong during escape analysis,
-// but for now it's the most convenient place for some rewrites.
-
-// fixRecoverCall rewrites an ORECOVER call into ORECOVERFP,
-// adding an explicit frame pointer argument.
-// If call is not an ORECOVER call, it's left unmodified.
-func fixRecoverCall(call *ir.CallExpr) {
-	if call.Op() != ir.ORECOVER {
-		return
-	}
-
-	pos := call.Pos()
-
-	// FP is equal to caller's SP plus FixedFrameSize.
-	var fp ir.Node = ir.NewCallExpr(pos, ir.OGETCALLERSP, nil, nil)
-	if off := base.Ctxt.Arch.FixedFrameSize; off != 0 {
-		fp = ir.NewBinaryExpr(fp.Pos(), ir.OADD, fp, ir.NewInt(base.Pos, off))
-	}
-	// TODO(mdempsky): Replace *int32 with unsafe.Pointer, without upsetting checkptr.
-	fp = ir.NewConvExpr(pos, ir.OCONVNOP, types.NewPtr(types.Types[types.TINT32]), fp)
-
-	call.SetOp(ir.ORECOVERFP)
-	call.Args = []ir.Node{typecheck.Expr(fp)}
-}

src/cmd/compile/internal/escape/expr.go

@@ -139,7 +139,7 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 		e.discard(n.X)
 
 	case ir.OCALLMETH, ir.OCALLFUNC, ir.OCALLINTER, ir.OINLCALL,
-		ir.OLEN, ir.OCAP, ir.OMIN, ir.OMAX, ir.OCOMPLEX, ir.OREAL, ir.OIMAG, ir.OAPPEND, ir.OCOPY, ir.ORECOVER,
+		ir.OLEN, ir.OCAP, ir.OMIN, ir.OMAX, ir.OCOMPLEX, ir.OREAL, ir.OIMAG, ir.OAPPEND, ir.OCOPY, ir.ORECOVERFP,
 		ir.OUNSAFEADD, ir.OUNSAFESLICE, ir.OUNSAFESTRING, ir.OUNSAFESTRINGDATA, ir.OUNSAFESLICEDATA:
 		e.call([]hole{k}, n)
 

src/cmd/compile/internal/escape/stmt.go

@@ -182,7 +182,7 @@ func (e *escape) stmt(n ir.Node) {
 			dsts[i] = res.Nname.(*ir.Name)
 		}
 		e.assignList(dsts, n.Results, "return", n)
-	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER, ir.OINLCALL, ir.OCLEAR, ir.OCLOSE, ir.OCOPY, ir.ODELETE, ir.OPANIC, ir.OPRINT, ir.OPRINTN, ir.ORECOVER:
+	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER, ir.OINLCALL, ir.OCLEAR, ir.OCLOSE, ir.OCOPY, ir.ODELETE, ir.OPANIC, ir.OPRINT, ir.OPRINTN, ir.ORECOVERFP:
 		e.call(nil, n)
 	case ir.OGO, ir.ODEFER:
 		n := n.(*ir.GoDeferStmt)

src/cmd/compile/internal/inline/inl.go

@@ -626,6 +626,8 @@ func (v *hairyVisitor) doNode(n ir.Node) bool {
 		v.budget -= inlineExtraPanicCost
 
 	case ir.ORECOVER:
+		base.FatalfAt(n.Pos(), "ORECOVER missed typecheck")
+	case ir.ORECOVERFP:
 		// recover matches the argument frame pointer to find
 		// the right panic value, so it needs an argument frame.
 		v.reason = "call to recover"

src/cmd/compile/internal/typecheck/const.go

@@ -518,6 +518,7 @@ func callOrChan(n ir.Node) bool {
 		ir.OPRINTN,
 		ir.OREAL,
 		ir.ORECOVER,
+		ir.ORECOVERFP,
 		ir.ORECV,
 		ir.OUNSAFEADD,
 		ir.OUNSAFESLICE,

src/cmd/compile/internal/typecheck/func.go

@@ -830,22 +830,17 @@ func tcRecover(n *ir.CallExpr) ir.Node {
 		return n
 	}
 
-	n.SetType(types.Types[types.TINTER])
-	return n
-}
-
-// tcRecoverFP typechecks an ORECOVERFP node.
-func tcRecoverFP(n *ir.CallExpr) ir.Node {
-	if len(n.Args) != 1 {
-		base.FatalfAt(n.Pos(), "wrong number of arguments: %v", n)
-	}
-
-	n.Args[0] = Expr(n.Args[0])
-	if !n.Args[0].Type().IsPtrShaped() {
-		base.FatalfAt(n.Pos(), "%L is not pointer shaped", n.Args[0])
+	// FP is equal to caller's SP plus FixedFrameSize.
+	var fp ir.Node = ir.NewCallExpr(n.Pos(), ir.OGETCALLERSP, nil, nil)
+	if off := base.Ctxt.Arch.FixedFrameSize; off != 0 {
+		fp = ir.NewBinaryExpr(n.Pos(), ir.OADD, fp, ir.NewInt(base.Pos, off))
 	}
+	// TODO(mdempsky): Replace *int32 with unsafe.Pointer, without upsetting checkptr.
+	fp = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, types.NewPtr(types.Types[types.TINT32]), fp)
 
+	n.SetOp(ir.ORECOVERFP)
 	n.SetType(types.Types[types.TINTER])
+	n.Args = []ir.Node{Expr(fp)}
 	return n
 }
 

src/cmd/compile/internal/typecheck/stmt.go

@@ -283,7 +283,8 @@ func tcGoDefer(n *ir.GoDeferStmt) {
 		ir.OPANIC,
 		ir.OPRINT,
 		ir.OPRINTN,
-		ir.ORECOVER:
+		ir.ORECOVER,
+		ir.ORECOVERFP:
 		return
 
 	case ir.OAPPEND,

src/cmd/compile/internal/typecheck/typecheck.go

@@ -661,10 +661,6 @@ func typecheck1(n ir.Node, top int) ir.Node {
 		n := n.(*ir.CallExpr)
 		return tcRecover(n)
 
-	case ir.ORECOVERFP:
-		n := n.(*ir.CallExpr)
-		return tcRecoverFP(n)
-
 	case ir.OUNSAFEADD:
 		n := n.(*ir.BinaryExpr)
 		return tcUnsafeAdd(n)