all: add SliceToArrayPointer instruction
CL 332049 added support for slice to array pointer, which introduced in
go1.17, by using Convert instruction. However, the conversion can fail
dynamically, while all current conversion instructions can not. That
leads to inconsistent with other parts of SSA IR.
@timothy-king suggested to add new instruction for this conversion, this
CL implements that.
Fixes golang/go#46987
Change-Id: I1a00d51e257d2b3eabc2c37e3a09b78754193a78
Reviewed-on: https://go-review.googlesource.com/c/tools/+/333749
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Tim King <taking@google.com>
diff --git a/go/ssa/builder.go b/go/ssa/builder.go
index 2d0fdaa..e1540db 100644
--- a/go/ssa/builder.go
+++ b/go/ssa/builder.go
@@ -579,6 +579,8 @@
y.pos = e.Lparen
case *MakeInterface:
y.pos = e.Lparen
+ case *SliceToArrayPointer:
+ y.pos = e.Lparen
}
}
return y
diff --git a/go/ssa/builder_go117_test.go b/go/ssa/builder_go117_test.go
index e7ba214..f6545e5 100644
--- a/go/ssa/builder_go117_test.go
+++ b/go/ssa/builder_go117_test.go
@@ -49,3 +49,34 @@
})
}
}
+
+func TestBuildPackageFailuresGo117(t *testing.T) {
+ tests := []struct {
+ name string
+ src string
+ importer types.Importer
+ }{
+ {"slice to array pointer - source is not a slice", "package p; var s [4]byte; var _ = (*[4]byte)(s)", nil},
+ {"slice to array pointer - dest is not a pointer", "package p; var s []byte; var _ = ([4]byte)(s)", nil},
+ {"slice to array pointer - dest pointer elem is not an array", "package p; var s []byte; var _ = (*byte)(s)", nil},
+ }
+
+ for _, tc := range tests {
+ tc := tc
+ t.Run(tc.name, func(t *testing.T) {
+ t.Parallel()
+ fset := token.NewFileSet()
+ f, err := parser.ParseFile(fset, "p.go", tc.src, parser.ParseComments)
+ if err != nil {
+ t.Error(err)
+ }
+ files := []*ast.File{f}
+
+ pkg := types.NewPackage("p", "")
+ conf := &types.Config{Importer: tc.importer}
+ if _, _, err := ssautil.BuildPackage(conf, fset, pkg, files, ssa.SanityCheckFunctions); err == nil {
+ t.Error("want error, but got nil")
+ }
+ })
+ }
+}
diff --git a/go/ssa/doc.go b/go/ssa/doc.go
index 1a13640..fe0099b 100644
--- a/go/ssa/doc.go
+++ b/go/ssa/doc.go
@@ -50,50 +50,51 @@
// Instruction interfaces. The following table shows for each
// concrete type which of these interfaces it implements.
//
-// Value? Instruction? Member?
-// *Alloc ✔ ✔
-// *BinOp ✔ ✔
-// *Builtin ✔
-// *Call ✔ ✔
-// *ChangeInterface ✔ ✔
-// *ChangeType ✔ ✔
-// *Const ✔
-// *Convert ✔ ✔
-// *DebugRef ✔
-// *Defer ✔
-// *Extract ✔ ✔
-// *Field ✔ ✔
-// *FieldAddr ✔ ✔
-// *FreeVar ✔
-// *Function ✔ ✔ (func)
-// *Global ✔ ✔ (var)
-// *Go ✔
-// *If ✔
-// *Index ✔ ✔
-// *IndexAddr ✔ ✔
-// *Jump ✔
-// *Lookup ✔ ✔
-// *MakeChan ✔ ✔
-// *MakeClosure ✔ ✔
-// *MakeInterface ✔ ✔
-// *MakeMap ✔ ✔
-// *MakeSlice ✔ ✔
-// *MapUpdate ✔
-// *NamedConst ✔ (const)
-// *Next ✔ ✔
-// *Panic ✔
-// *Parameter ✔
-// *Phi ✔ ✔
-// *Range ✔ ✔
-// *Return ✔
-// *RunDefers ✔
-// *Select ✔ ✔
-// *Send ✔
-// *Slice ✔ ✔
-// *Store ✔
-// *Type ✔ (type)
-// *TypeAssert ✔ ✔
-// *UnOp ✔ ✔
+// Value? Instruction? Member?
+// *Alloc ✔ ✔
+// *BinOp ✔ ✔
+// *Builtin ✔
+// *Call ✔ ✔
+// *ChangeInterface ✔ ✔
+// *ChangeType ✔ ✔
+// *Const ✔
+// *Convert ✔ ✔
+// *SliceToArrayPointer ✔ ✔
+// *DebugRef ✔
+// *Defer ✔
+// *Extract ✔ ✔
+// *Field ✔ ✔
+// *FieldAddr ✔ ✔
+// *FreeVar ✔
+// *Function ✔ ✔ (func)
+// *Global ✔ ✔ (var)
+// *Go ✔
+// *If ✔
+// *Index ✔ ✔
+// *IndexAddr ✔ ✔
+// *Jump ✔
+// *Lookup ✔ ✔
+// *MakeChan ✔ ✔
+// *MakeClosure ✔ ✔
+// *MakeInterface ✔ ✔
+// *MakeMap ✔ ✔
+// *MakeSlice ✔ ✔
+// *MapUpdate ✔
+// *NamedConst ✔ (const)
+// *Next ✔ ✔
+// *Panic ✔
+// *Parameter ✔
+// *Phi ✔ ✔
+// *Range ✔ ✔
+// *Return ✔
+// *RunDefers ✔
+// *Select ✔ ✔
+// *Send ✔
+// *Slice ✔ ✔
+// *Store ✔
+// *Type ✔ (type)
+// *TypeAssert ✔ ✔
+// *UnOp ✔ ✔
//
// Other key types in this package include: Program, Package, Function
// and BasicBlock.
diff --git a/go/ssa/emit.go b/go/ssa/emit.go
index df9ca4f..02d0e4b 100644
--- a/go/ssa/emit.go
+++ b/go/ssa/emit.go
@@ -232,7 +232,7 @@
if slice, ok := ut_src.(*types.Slice); ok {
if ptr, ok := ut_dst.(*types.Pointer); ok {
if arr, ok := ptr.Elem().(*types.Array); ok && types.Identical(slice.Elem(), arr.Elem()) {
- c := &Convert{X: val}
+ c := &SliceToArrayPointer{X: val}
c.setType(ut_dst)
return f.emit(c)
}
diff --git a/go/ssa/interp/interp.go b/go/ssa/interp/interp.go
index d776594..bf78622 100644
--- a/go/ssa/interp/interp.go
+++ b/go/ssa/interp/interp.go
@@ -210,6 +210,9 @@
case *ssa.Convert:
fr.env[instr] = conv(instr.Type(), instr.X.Type(), fr.get(instr.X))
+ case *ssa.SliceToArrayPointer:
+ fr.env[instr] = sliceToArrayPointer(instr.Type(), instr.X.Type(), fr.get(instr.X))
+
case *ssa.MakeInterface:
fr.env[instr] = iface{t: instr.X.Type(), v: fr.get(instr.X)}
diff --git a/go/ssa/interp/interp_go117_test.go b/go/ssa/interp/interp_go117_test.go
new file mode 100644
index 0000000..58bbaa3
--- /dev/null
+++ b/go/ssa/interp/interp_go117_test.go
@@ -0,0 +1,12 @@
+// 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.
+
+//go:build go1.17
+// +build go1.17
+
+package interp_test
+
+func init() {
+ testdataTests = append(testdataTests, "slice2arrayptr.go")
+}
diff --git a/go/ssa/interp/ops.go b/go/ssa/interp/ops.go
index 90d9452..9c12d4a 100644
--- a/go/ssa/interp/ops.go
+++ b/go/ssa/interp/ops.go
@@ -1357,6 +1357,29 @@
panic(fmt.Sprintf("unsupported conversion: %s -> %s, dynamic type %T", t_src, t_dst, x))
}
+// sliceToArrayPointer converts the value x of type slice to type t_dst
+// a pointer to array and returns the result.
+func sliceToArrayPointer(t_dst, t_src types.Type, x value) value {
+ utSrc := t_src.Underlying()
+ utDst := t_dst.Underlying()
+
+ if _, ok := utSrc.(*types.Slice); ok {
+ if utSrc, ok := utDst.(*types.Pointer); ok {
+ if arr, ok := utSrc.Elem().(*types.Array); ok {
+ x := x.([]value)
+ a := make(array, arr.Len())
+ for i := range a {
+ a[i] = x[i]
+ }
+ v := value(a)
+ return &v
+ }
+ }
+ }
+
+ panic(fmt.Sprintf("unsupported conversion: %s -> %s, dynamic type %T", t_src, t_dst, x))
+}
+
// checkInterface checks that the method set of x implements the
// interface itype.
// On success it returns "", on failure, an error message.
diff --git a/go/ssa/interp/testdata/slice2arrayptr.go b/go/ssa/interp/testdata/slice2arrayptr.go
new file mode 100644
index 0000000..21f9906
--- /dev/null
+++ b/go/ssa/interp/testdata/slice2arrayptr.go
@@ -0,0 +1,23 @@
+// 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 main
+
+// Test for slice to array pointer conversion introduced in go1.17
+
+import "fmt"
+
+var s = []byte{1, 2, 3, 4}
+var a = (*[4]byte)(s)
+
+func main() {
+ for i := range s {
+ if a[i] != s[i] {
+ panic(fmt.Sprintf("value mismatched: %v - %v\n", a[i], s[i]))
+ }
+ if (*a)[i] != s[i] {
+ panic(fmt.Sprintf("value mismatched: %v - %v\n", (*a)[i], s[i]))
+ }
+ }
+}
diff --git a/go/ssa/print.go b/go/ssa/print.go
index 3333ba4..c1b6d22 100644
--- a/go/ssa/print.go
+++ b/go/ssa/print.go
@@ -159,10 +159,11 @@
relName(x, v.(Instruction)))
}
-func (v *ChangeType) String() string { return printConv("changetype", v, v.X) }
-func (v *Convert) String() string { return printConv("convert", v, v.X) }
-func (v *ChangeInterface) String() string { return printConv("change interface", v, v.X) }
-func (v *MakeInterface) String() string { return printConv("make", v, v.X) }
+func (v *ChangeType) String() string { return printConv("changetype", v, v.X) }
+func (v *Convert) String() string { return printConv("convert", v, v.X) }
+func (v *ChangeInterface) String() string { return printConv("change interface", v, v.X) }
+func (v *SliceToArrayPointer) String() string { return printConv("slice to array pointer", v, v.X) }
+func (v *MakeInterface) String() string { return printConv("make", v, v.X) }
func (v *MakeClosure) String() string {
var b bytes.Buffer
diff --git a/go/ssa/sanity.go b/go/ssa/sanity.go
index 16df7e4..1d4e20f 100644
--- a/go/ssa/sanity.go
+++ b/go/ssa/sanity.go
@@ -132,14 +132,8 @@
case *Call:
case *ChangeInterface:
case *ChangeType:
+ case *SliceToArrayPointer:
case *Convert:
- if _, ok := instr.X.Type().Underlying().(*types.Slice); ok {
- if ptr, ok := instr.Type().Underlying().(*types.Pointer); ok {
- if _, ok := ptr.Elem().(*types.Array); ok {
- break
- }
- }
- }
if _, ok := instr.X.Type().Underlying().(*types.Basic); !ok {
if _, ok := instr.Type().Underlying().(*types.Basic); !ok {
s.errorf("convert %s -> %s: at least one type must be basic", instr.X.Type(), instr.Type())
diff --git a/go/ssa/ssa.go b/go/ssa/ssa.go
index d3faf44..8358681 100644
--- a/go/ssa/ssa.go
+++ b/go/ssa/ssa.go
@@ -615,9 +615,10 @@
// - between pointers and unsafe.Pointer.
// - between unsafe.Pointer and uintptr.
// - from (Unicode) integer to (UTF-8) string.
-// - from slice to array pointer.
// A conversion may imply a type name change also.
//
+// This operation cannot fail dynamically.
+//
// Conversions of untyped string/number/bool constants to a specific
// representation are eliminated during SSA construction.
//
@@ -649,6 +650,20 @@
X Value
}
+// The SliceToArrayPointer instruction yields the conversion of slice X to
+// array pointer.
+//
+// Pos() returns the ast.CallExpr.Lparen, if the instruction arose
+// from an explicit conversion in the source.
+//
+// Example printed form:
+// t1 = slice to array pointer *[4]byte <- []byte (t0)
+//
+type SliceToArrayPointer struct {
+ register
+ X Value
+}
+
// MakeInterface constructs an instance of an interface type from a
// value of a concrete type.
//
@@ -1566,6 +1581,10 @@
return append(rands, &v.X)
}
+func (v *SliceToArrayPointer) Operands(rands []*Value) []*Value {
+ return append(rands, &v.X)
+}
+
func (s *DebugRef) Operands(rands []*Value) []*Value {
return append(rands, &s.X)
}
