From 1be5add6c585fa8bfb57b37453b7c50b533fa325 Mon Sep 17 00:00:00 2001
From: Konstantin8105 <konstantin8105@gmail.com>
Date: Tue, 13 Nov 2018 15:17:14 +0300
Subject: [PATCH] Proposal: find variables without pointer problem

---
 transpiler/functions.go  | 117 +++++++++++++++++++++++++++++++++++++++
 transpiler/transpiler.go |   6 ++
 transpiler/unary.go      |  18 ++++++
 3 files changed, 141 insertions(+)

diff --git a/transpiler/functions.go b/transpiler/functions.go
index 0801ad81..82fa078c 100644
--- a/transpiler/functions.go
+++ b/transpiler/functions.go
@@ -361,3 +361,120 @@ func transpileReturnStmt(n *ast.ReturnStmt, p *program.Program) (
 		Results: results,
 	}, preStmts, postStmts, nil
 }
+
+// analyze function
+func analyzeFunctionDec(n *ast.FunctionDecl, p *program.Program) (names []string) {
+	// create list of variables not pointer
+	var f func(ast.Node)
+	f = func(a ast.Node) {
+		switch v := a.(type) {
+		case *ast.VarDecl:
+			if types.IsPointer(v.Type) || types.IsFunction(v.Type) {
+				return
+			}
+			if !(types.IsCInteger(p, v.Type) || types.IsCFloat(p, v.Type)) {
+				return
+			}
+			names = append(names, v.Name)
+		default:
+			if a != nil {
+				for i := range a.Children() {
+					if a.Children() != nil {
+						f(a.Children()[i])
+					}
+				}
+			}
+		}
+	}
+	f(n)
+
+	if len(names) == 0 {
+		return
+	}
+
+	// find all using
+	var excluder func(ast.Node, string) bool
+
+	var unaryEx func(ast.Node, string) bool
+	unaryEx = func(a ast.Node, name string) bool {
+		switch v := a.(type) {
+		case *ast.UnaryOperator:
+			// `-UnaryOperator 0x32d53e8 'float *' prefix '&'
+			//   `-DeclRefExpr 0x32d53c0 'float' lvalue Var 0x32d5298 'o' 'float' <<-----
+			if decl, ok := v.Children()[0].(*ast.DeclRefExpr); ok {
+				if decl.Name == name {
+					return true
+				}
+			} else {
+				return unaryEx(v.Children()[0], name)
+			}
+
+		default:
+			if a != nil {
+				for i := range a.Children() {
+					if a.Children()[i] != nil {
+						if unaryEx(a.Children()[i], name) {
+							return true
+						}
+					}
+				}
+			}
+		}
+		return false
+	}
+
+	excluder = func(a ast.Node, name string) bool {
+		switch v := a.(type) {
+		case *ast.VarDecl:
+			// VarDecl used oo 'float *' cinit
+			// `-UnaryOperator 0x32d53e8 'float *' prefix '&'
+			//   `-DeclRefExpr 0x32d53c0 'float' lvalue Var 0x32d5298 'o' 'float' <<-----
+			if len(v.Children()) != 0 {
+				return unaryEx(v, name)
+			}
+
+		case *ast.CallExpr:
+			// CallExpr 'double *'
+			// |-ImplicitCastExpr  'double *(*)(int *const *, double *)' <FunctionToPointerDecay>
+			// | `-DeclRefExpr  'double *(int *const *, double *)' Function 0x30e9f38 'returner' ...
+			// |-ImplicitCastExpr 'int *const *' <NullToPointer>
+			// | `-IntegerLiteral 'int' 0
+			// `-UnaryOperator 'double *' prefix '&'
+			//   `-DeclRefExpr 'double' lvalue Var 0x30ed938 'fd' 'double'
+			if len(v.Children()) != 0 {
+				return unaryEx(v, name)
+			}
+
+		case *ast.BinaryOperator:
+			// BinaryOperator  'int *' '='
+			// |-DeclRefExpr 'int *' lvalue Var 0x294fbb0 'b' 'int *'
+			// `-UnaryOperator 'int *' prefix '&'
+			//   `-DeclRefExpr 'int' lvalue Var 0x294fb00 'a' 'int' <<--
+			if len(v.Children()) != 0 {
+				return unaryEx(v, name)
+			}
+
+		default:
+			if a != nil {
+				for i := range a.Children() {
+					if a.Children()[i] != nil {
+						if excluder(a.Children()[i], name) {
+							return true
+						}
+					}
+				}
+			}
+		}
+		return false
+	}
+
+	var correctNames []string
+	for i := range names {
+		if excluder(n, names[i]) {
+			continue
+		}
+		correctNames = append(correctNames, names[i])
+	}
+
+	return correctNames
+}
diff --git a/transpiler/transpiler.go b/transpiler/transpiler.go
index 163e3543..08023d90 100644
--- a/transpiler/transpiler.go
+++ b/transpiler/transpiler.go
@@ -372,6 +372,8 @@ func transpileToStmt(node ast.Node, p *program.Program) (
 	return
 }
 
+var VarNameNotPointer []string
+
 func transpileToNode(node ast.Node, p *program.Program) (
 	decls []goast.Decl, err error) {
 	defer func() {
@@ -403,6 +405,10 @@ func transpileToNode(node ast.Node, p *program.Program) (
 
 	switch n := node.(type) {
 	case *ast.FunctionDecl:
+		// analyze variables
+		VarNameNotPointer = analyzeFunctionDec(n, p)
+
+		// transpile
 		com := p.GetComments(node.Position())
 		decls, err = transpileFunctionDecl(n, p)
 		if len(decls) > 0 {
diff --git a/transpiler/unary.go b/transpiler/unary.go
index 3e8b8f35..956d248b 100644
--- a/transpiler/unary.go
+++ b/transpiler/unary.go
@@ -265,6 +265,24 @@ func transpileUnaryOperatorAmpersant(n *ast.UnaryOperator, p *program.Program) (
 		return
 	}
 
+	if decl, ok := n.Children()[0].(*ast.DeclRefExpr); ok {
+		var found bool
+		for i := range VarNameNotPointer {
+			if decl.Name == VarNameNotPointer[i] {
+				found = true
+				break
+			}
+		}
+		if found {
+			expr = &goast.UnaryExpr{
+				Op: token.AND, // &
+				X:  util.NewIdent(decl.Name),
+			}
+			eType = n.Type
+			return
+		}
+	}
+
 	p.AddImport("unsafe")
 	expr = util.CreateSliceFromReference(resolvedType, expr)