cmd/compile/internal/noder: stop preserving original const strings

One of the more tedious quirks of the original frontend (i.e.,
typecheck) to preserve was that it preserved the original
representation of constants into the backend. To fit into the unified
IR model, I ended up implementing a fairly heavyweight workaround:
simply record the original constant's string expression in the export
data, so that diagnostics could still report it back, and match the
old test expectations.

But now that there's just a single frontend to support, it's easy
enough to just update the test expectations and drop this support for
"raw" constant expressions.

Change-Id: I1d859c5109d679879d937a2b213e777fbddf4f2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/526376
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

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

@@ -498,20 +498,6 @@ func NewParenExpr(pos src.XPos, x Node) *ParenExpr {
 func (n *ParenExpr) Implicit() bool     { return n.flags&miniExprImplicit != 0 }
 func (n *ParenExpr) SetImplicit(b bool) { n.flags.set(miniExprImplicit, b) }
 
-// A RawOrigExpr represents an arbitrary Go expression as a string value.
-// When printed in diagnostics, the string value is written out exactly as-is.
-type RawOrigExpr struct {
-	miniExpr
-	Raw string
-}
-
-func NewRawOrigExpr(pos src.XPos, op Op, raw string) *RawOrigExpr {
-	n := &RawOrigExpr{Raw: raw}
-	n.pos = pos
-	n.op = op
-	return n
-}
-
 // A ResultExpr represents a direct access to a result.
 type ResultExpr struct {
 	miniExpr

src/cmd/compile/internal/ir/fmt.go

@@ -567,11 +567,6 @@ func exprFmt(n Node, s fmt.State, prec int) {
 		return
 	}
 
-	if n, ok := n.(*RawOrigExpr); ok {
-		fmt.Fprint(s, n.Raw)
-		return
-	}
-
 	switch n.Op() {
 	case OPAREN:
 		n := n.(*ParenExpr)

src/cmd/compile/internal/ir/node_gen.go

@@ -1171,25 +1171,6 @@ func (n *RangeStmt) editChildrenWithHidden(edit func(Node) Node) {
 	}
 }
 
-func (n *RawOrigExpr) Format(s fmt.State, verb rune) { fmtNode(n, s, verb) }
-func (n *RawOrigExpr) copy() Node {
-	c := *n
-	c.init = copyNodes(c.init)
-	return &c
-}
-func (n *RawOrigExpr) doChildren(do func(Node) bool) bool {
-	if doNodes(n.init, do) {
-		return true
-	}
-	return false
-}
-func (n *RawOrigExpr) editChildren(edit func(Node) Node) {
-	editNodes(n.init, edit)
-}
-func (n *RawOrigExpr) editChildrenWithHidden(edit func(Node) Node) {
-	editNodes(n.init, edit)
-}
-
 func (n *ResultExpr) Format(s fmt.State, verb rune) { fmtNode(n, s, verb) }
 func (n *ResultExpr) copy() Node {
 	c := *n

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

@@ -1,34 +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 noder
-
-import (
-	"fmt"
-
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/syntax"
-)
-
-// constExprOp returns an ir.Op that represents the outermost
-// operation of the given constant expression. It's intended for use
-// with ir.RawOrigExpr.
-func constExprOp(expr syntax.Expr) ir.Op {
-	switch expr := expr.(type) {
-	default:
-		panic(fmt.Sprintf("%s: unexpected expression: %T", expr.Pos(), expr))
-
-	case *syntax.BasicLit:
-		return ir.OLITERAL
-	case *syntax.Name, *syntax.SelectorExpr:
-		return ir.ONAME
-	case *syntax.CallExpr:
-		return ir.OCALL
-	case *syntax.Operation:
-		if expr.Y == nil {
-			return unOps[expr.Op]
-		}
-		return binOps[expr.Op]
-	}
-}

src/cmd/compile/internal/noder/helpers.go

@@ -40,11 +40,6 @@ func typed(typ *types.Type, n ir.Node) ir.Node {
 
 // Values
 
-func OrigConst(pos src.XPos, typ *types.Type, val constant.Value, op ir.Op, raw string) ir.Node {
-	orig := ir.NewRawOrigExpr(pos, op, raw)
-	return ir.NewConstExpr(val, typed(typ, orig))
-}
-
 // FixValue returns val after converting and truncating it as
 // appropriate for typ.
 func FixValue(typ *types.Type, val constant.Value) constant.Value {

src/cmd/compile/internal/noder/reader.go

@@ -2172,9 +2172,7 @@ func (r *reader) expr() (res ir.Node) {
 		pos := r.pos()
 		typ := r.typ()
 		val := FixValue(typ, r.Value())
-		op := r.op()
-		orig := r.String()
-		return typecheck.Expr(OrigConst(pos, typ, val, op, orig))
+		return typed(typ, ir.NewBasicLit(pos, val))
 
 	case exprNil:
 		pos := r.pos()

src/cmd/compile/internal/noder/writer.go

@@ -1748,11 +1748,6 @@ func (w *writer) expr(expr syntax.Expr) {
 			assert(typ != nil)
 			w.typ(typ)
 			w.Value(tv.Value)
-
-			// TODO(mdempsky): These details are only important for backend
-			// diagnostics. Explore writing them out separately.
-			w.op(constExprOp(expr))
-			w.String(syntax.String(expr))
 			return
 		}
 

test/escape5.go

@@ -151,7 +151,7 @@ func f9() {
 func f10() {
 	// These don't escape but are too big for the stack
 	var x [1 << 30]byte         // ERROR "moved to heap: x"
-	var y = make([]byte, 1<<30) // ERROR "make\(\[\]byte, 1 << 30\) escapes to heap"
+	var y = make([]byte, 1<<30) // ERROR "make\(\[\]byte, 1073741824\) escapes to heap"
 	_ = x[0] + y[0]
 }
 

test/escape_reflect.go

@@ -352,9 +352,9 @@ func select2(ch chan string, x string) { // ERROR "leaking param: ch$" "leaking
 }
 
 var (
-	intTyp    = reflect.TypeOf(int(0))     // ERROR "int\(0\) does not escape"
+	intTyp    = reflect.TypeOf(int(0))     // ERROR "0 does not escape"
 	uintTyp   = reflect.TypeOf(uint(0))    // ERROR "uint\(0\) does not escape"
-	stringTyp = reflect.TypeOf(string("")) // ERROR "string\(.*\) does not escape"
+	stringTyp = reflect.TypeOf(string("")) // ERROR ".. does not escape"
 	bytesTyp  = reflect.TypeOf([]byte{})   // ERROR "\[\]byte{} does not escape"
 )
 

test/escape_slice.go

@@ -137,7 +137,7 @@ const (
 var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}
 
 func IPv4(a, b, c, d byte) IP {
-	p := make(IP, IPv6len) // ERROR "make\(IP, IPv6len\) escapes to heap"
+	p := make(IP, IPv6len) // ERROR "make\(IP, 16\) escapes to heap"
 	copy(p, v4InV6Prefix)
 	p[12] = a
 	p[13] = b

test/fixedbugs/issue13799.go

@@ -61,7 +61,7 @@ func test1(iter int) {
 	}
 
 	if len(m) != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }
 
@@ -85,7 +85,7 @@ func test2(iter int) {
 	}
 
 	if len(m) != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }
 
@@ -111,7 +111,7 @@ func test3(iter int) {
 	}
 
 	if *m != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }
 
@@ -137,7 +137,7 @@ func test4(iter int) {
 	}
 
 	if *m != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }
 
@@ -168,7 +168,7 @@ func test5(iter int) {
 	}
 
 	if *m != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }
 
@@ -186,6 +186,6 @@ func test6(iter int) {
 	}
 
 	if *m != maxI {
-		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
+		panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "500 escapes to heap$" "... argument does not escape$" "fmt.Sprintf\(.*\) escapes to heap"
 	}
 }