Adding upstream version 1.18.10.upstream/1.18.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 364 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/syntax/positions.go b/src/cmd/compile/internal/syntax/positions.go
new file mode 100644
index 0000000..9359655
--- /dev/null
+++ b/src/cmd/compile/internal/syntax/positions.go
@@ -0,0 +1,364 @@
+// Copyright 2020 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.
+
+// This file implements helper functions for scope position computations.
+
+package syntax
+
+// StartPos returns the start position of n.
+func StartPos(n Node) Pos {
+	// Cases for nodes which don't need a correction are commented out.
+	for m := n; ; {
+		switch n := m.(type) {
+		case nil:
+			panic("nil node")
+
+		// packages
+		case *File:
+			// file block starts at the beginning of the file
+			return MakePos(n.Pos().Base(), 1, 1)
+
+		// declarations
+		// case *ImportDecl:
+		// case *ConstDecl:
+		// case *TypeDecl:
+		// case *VarDecl:
+		// case *FuncDecl:
+
+		// expressions
+		// case *BadExpr:
+		// case *Name:
+		// case *BasicLit:
+		case *CompositeLit:
+			if n.Type != nil {
+				m = n.Type
+				continue
+			}
+			return n.Pos()
+		// case *KeyValueExpr:
+		// case *FuncLit:
+		// case *ParenExpr:
+		case *SelectorExpr:
+			m = n.X
+		case *IndexExpr:
+			m = n.X
+		// case *SliceExpr:
+		case *AssertExpr:
+			m = n.X
+		case *TypeSwitchGuard:
+			if n.Lhs != nil {
+				m = n.Lhs
+				continue
+			}
+			m = n.X
+		case *Operation:
+			if n.Y != nil {
+				m = n.X
+				continue
+			}
+			return n.Pos()
+		case *CallExpr:
+			m = n.Fun
+		case *ListExpr:
+			if len(n.ElemList) > 0 {
+				m = n.ElemList[0]
+				continue
+			}
+			return n.Pos()
+		// types
+		// case *ArrayType:
+		// case *SliceType:
+		// case *DotsType:
+		// case *StructType:
+		// case *Field:
+		// case *InterfaceType:
+		// case *FuncType:
+		// case *MapType:
+		// case *ChanType:
+
+		// statements
+		// case *EmptyStmt:
+		// case *LabeledStmt:
+		// case *BlockStmt:
+		// case *ExprStmt:
+		case *SendStmt:
+			m = n.Chan
+		// case *DeclStmt:
+		case *AssignStmt:
+			m = n.Lhs
+		// case *BranchStmt:
+		// case *CallStmt:
+		// case *ReturnStmt:
+		// case *IfStmt:
+		// case *ForStmt:
+		// case *SwitchStmt:
+		// case *SelectStmt:
+
+		// helper nodes
+		case *RangeClause:
+			if n.Lhs != nil {
+				m = n.Lhs
+				continue
+			}
+			m = n.X
+		// case *CaseClause:
+		// case *CommClause:
+
+		default:
+			return n.Pos()
+		}
+	}
+}
+
+// EndPos returns the approximate end position of n in the source.
+// For some nodes (*Name, *BasicLit) it returns the position immediately
+// following the node; for others (*BlockStmt, *SwitchStmt, etc.) it
+// returns the position of the closing '}'; and for some (*ParenExpr)
+// the returned position is the end position of the last enclosed
+// expression.
+// Thus, EndPos should not be used for exact demarcation of the
+// end of a node in the source; it is mostly useful to determine
+// scope ranges where there is some leeway.
+func EndPos(n Node) Pos {
+	for m := n; ; {
+		switch n := m.(type) {
+		case nil:
+			panic("nil node")
+
+		// packages
+		case *File:
+			return n.EOF
+
+		// declarations
+		case *ImportDecl:
+			m = n.Path
+		case *ConstDecl:
+			if n.Values != nil {
+				m = n.Values
+				continue
+			}
+			if n.Type != nil {
+				m = n.Type
+				continue
+			}
+			if l := len(n.NameList); l > 0 {
+				m = n.NameList[l-1]
+				continue
+			}
+			return n.Pos()
+		case *TypeDecl:
+			m = n.Type
+		case *VarDecl:
+			if n.Values != nil {
+				m = n.Values
+				continue
+			}
+			if n.Type != nil {
+				m = n.Type
+				continue
+			}
+			if l := len(n.NameList); l > 0 {
+				m = n.NameList[l-1]
+				continue
+			}
+			return n.Pos()
+		case *FuncDecl:
+			if n.Body != nil {
+				m = n.Body
+				continue
+			}
+			m = n.Type
+
+		// expressions
+		case *BadExpr:
+			return n.Pos()
+		case *Name:
+			p := n.Pos()
+			return MakePos(p.Base(), p.Line(), p.Col()+uint(len(n.Value)))
+		case *BasicLit:
+			p := n.Pos()
+			return MakePos(p.Base(), p.Line(), p.Col()+uint(len(n.Value)))
+		case *CompositeLit:
+			return n.Rbrace
+		case *KeyValueExpr:
+			m = n.Value
+		case *FuncLit:
+			m = n.Body
+		case *ParenExpr:
+			m = n.X
+		case *SelectorExpr:
+			m = n.Sel
+		case *IndexExpr:
+			m = n.Index
+		case *SliceExpr:
+			for i := len(n.Index) - 1; i >= 0; i-- {
+				if x := n.Index[i]; x != nil {
+					m = x
+					continue
+				}
+			}
+			m = n.X
+		case *AssertExpr:
+			m = n.Type
+		case *TypeSwitchGuard:
+			m = n.X
+		case *Operation:
+			if n.Y != nil {
+				m = n.Y
+				continue
+			}
+			m = n.X
+		case *CallExpr:
+			if l := lastExpr(n.ArgList); l != nil {
+				m = l
+				continue
+			}
+			m = n.Fun
+		case *ListExpr:
+			if l := lastExpr(n.ElemList); l != nil {
+				m = l
+				continue
+			}
+			return n.Pos()
+
+		// types
+		case *ArrayType:
+			m = n.Elem
+		case *SliceType:
+			m = n.Elem
+		case *DotsType:
+			m = n.Elem
+		case *StructType:
+			if l := lastField(n.FieldList); l != nil {
+				m = l
+				continue
+			}
+			return n.Pos()
+			// TODO(gri) need to take TagList into account
+		case *Field:
+			if n.Type != nil {
+				m = n.Type
+				continue
+			}
+			m = n.Name
+		case *InterfaceType:
+			if l := lastField(n.MethodList); l != nil {
+				m = l
+				continue
+			}
+			return n.Pos()
+		case *FuncType:
+			if l := lastField(n.ResultList); l != nil {
+				m = l
+				continue
+			}
+			if l := lastField(n.ParamList); l != nil {
+				m = l
+				continue
+			}
+			return n.Pos()
+		case *MapType:
+			m = n.Value
+		case *ChanType:
+			m = n.Elem
+
+		// statements
+		case *EmptyStmt:
+			return n.Pos()
+		case *LabeledStmt:
+			m = n.Stmt
+		case *BlockStmt:
+			return n.Rbrace
+		case *ExprStmt:
+			m = n.X
+		case *SendStmt:
+			m = n.Value
+		case *DeclStmt:
+			if l := lastDecl(n.DeclList); l != nil {
+				m = l
+				continue
+			}
+			return n.Pos()
+		case *AssignStmt:
+			m = n.Rhs
+			if m == nil {
+				p := EndPos(n.Lhs)
+				return MakePos(p.Base(), p.Line(), p.Col()+2)
+			}
+		case *BranchStmt:
+			if n.Label != nil {
+				m = n.Label
+				continue
+			}
+			return n.Pos()
+		case *CallStmt:
+			m = n.Call
+		case *ReturnStmt:
+			if n.Results != nil {
+				m = n.Results
+				continue
+			}
+			return n.Pos()
+		case *IfStmt:
+			if n.Else != nil {
+				m = n.Else
+				continue
+			}
+			m = n.Then
+		case *ForStmt:
+			m = n.Body
+		case *SwitchStmt:
+			return n.Rbrace
+		case *SelectStmt:
+			return n.Rbrace
+
+		// helper nodes
+		case *RangeClause:
+			m = n.X
+		case *CaseClause:
+			if l := lastStmt(n.Body); l != nil {
+				m = l
+				continue
+			}
+			return n.Colon
+		case *CommClause:
+			if l := lastStmt(n.Body); l != nil {
+				m = l
+				continue
+			}
+			return n.Colon
+
+		default:
+			return n.Pos()
+		}
+	}
+}
+
+func lastDecl(list []Decl) Decl {
+	if l := len(list); l > 0 {
+		return list[l-1]
+	}
+	return nil
+}
+
+func lastExpr(list []Expr) Expr {
+	if l := len(list); l > 0 {
+		return list[l-1]
+	}
+	return nil
+}
+
+func lastStmt(list []Stmt) Stmt {
+	if l := len(list); l > 0 {
+		return list[l-1]
+	}
+	return nil
+}
+
+func lastField(list []*Field) *Field {
+	if l := len(list); l > 0 {
+		return list[l-1]
+	}
+	return nil
+}