Merge branch 'dev' of github.com:mewmew/uc into dev

ast/ast.go

@@ -731,7 +731,11 @@ func (n *TypeDef) Name() *Ident {
 //
 //    *BlockStmt
 func (n *FuncDecl) Value() Node {
-	return n.Body
+	// ref: https://golang.org/doc/faq#nil_error
+	if n.Body != nil {
+		return n.Body
+	}
+	return nil
 }
 
 // Value returns the initializing value of the defined identifier; or nil if
@@ -741,7 +745,11 @@ func (n *FuncDecl) Value() Node {
 //
 //    Expr
 func (n *VarDecl) Value() Node {
-	return n.Val
+	// ref: https://golang.org/doc/faq#nil_error
+	if n.Val != nil {
+		return n.Val
+	}
+	return nil
 }
 
 // Value returns the initializing value of the defined identifier; or nil if
@@ -751,7 +759,11 @@ func (n *VarDecl) Value() Node {
 //
 //    Type
 func (n *TypeDef) Value() Node {
-	return n.DeclType
+	// ref: https://golang.org/doc/faq#nil_error
+	if n.DeclType != nil {
+		return n.DeclType
+	}
+	return nil
 }
 
 // isDecl ensures that only declaration nodes can be assigned to the Decl

ast/astutil/astutil.go

@@ -5,5 +5,8 @@ import "github.com/mewmew/uc/ast"
 
 // IsDef reports whether the given declaration is a definition.
 func IsDef(decl ast.Decl) bool {
+	if _, ok := decl.(*ast.VarDecl); ok {
+		return true
+	}
 	return decl.Value() != nil
 }

report/sections/4_semantic_analysis/1_design_decisions.tex

@@ -1,8 +1,6 @@
 \subsection{Design Decisions}
 
 % TODO:
-% * your representation of types
-%    - Add GoDoc PDF of the uc/types package to appendix.
 % * what information you associate with identifiers in the environment
 % * how you chose to implement the environment (symbol table)
 % * how you handle delimited scopes (restoring the environment when leaving the scope)
@@ -16,9 +14,7 @@ \subsubsection{Multi-pass Identifier Resolution}
 
 \subsubsection{User-defined Type Definitions}
 
-Since day one, each stage of the compiler has been designed to support user-defined type definitions. Firstly, the lexer mimicked the implementation of Clang to address \textit{the lexer hack}\footnote{The lexer hack: \url{https://en.wikipedia.org/wiki/The_lexer_hack}} by tokenizing type keywords (e.g. \texttt{int}) as identifiers. Secondly, the grammar used to generate the parser was refined to define basic types in terms of identifiers and later extended to add support for the \texttt{typedef} construct. Lastly, the semantic analysis leveraged identifier resolution to provide a uniform representation of types by adding pre-declared type definitions of keyword types (e.g. \texttt{int}) to the \textit{universe} scope environment (as further described in section \ref{sec:scope}). As user-defined types (e.g. \texttt{typedef int foo;}) are synonyms for their underlying type (i.e. \texttt{foo} is an alias for \texttt{int}, see §6.7.7.3 \cite{c11_spec}), type definitions map identifiers to their underlying types within the type system.
-
-\footnote{Type declarations: \url{https://github.com/mewmew/uc/issues/54}}
+Since day one, each stage of the compiler has been designed to support user-defined type definitions. Firstly, the lexer mimicked the implementation of Clang to address \textit{the lexer hack}\footnote{The lexer hack: \url{https://en.wikipedia.org/wiki/The_lexer_hack}} by tokenizing type keywords (e.g. \texttt{int}) as identifiers. Secondly, the grammar used to generate the parser was refined to define basic types in terms of identifiers and later extended to add support for the \texttt{typedef} construct. Lastly, the semantic analysis leveraged identifier resolution to provide a uniform representation of types by adding pre-declared type definitions of keyword types (e.g. \texttt{int}) to the \textit{universe} scope environment (as further described in section \ref{sec:scope}). As user-defined types (e.g. \texttt{typedef int foo;}) are synonyms for their underlying type (i.e. \texttt{foo} is an alias for \texttt{int}, see §6.7.7.3 \cite{c11_spec}), type definitions map identifiers to their underlying types within the type system\footnote{Type declarations: \url{https://github.com/mewmew/uc/issues/54}}.
 
 \subsubsection{Typing Rules}
 

report/sections/4_semantic_analysis/2_implementation.tex

@@ -2,7 +2,9 @@ \subsection{Implementation}
 % TODO
 ... have been cross-referenced against §... of the C11 specification \cite{c11_spec}.
 
-\subsubsection{Type Representation}
+\subsubsection{Type Representations}
+
+See Appendix~\ref{app:semantic/types_doc}.
 
 \subsubsection{Typing Rules}
 

report/sections/appendices/4_semantic_analysis.tex

@@ -1,3 +1,9 @@
+\subsection{Type Representations}
+\label{app:semantic/types_doc}
+
+\includepdf[pages=-]{inc/sections/4_semantic_analysis/types_doc.pdf}
+
+\clearpage
 
 \subsection{Semantic Analysis Test Cases}
 \label{app:semantic/testcases}

sem/errors/errors.go

@@ -70,7 +70,11 @@ func (e *Error) Error() string {
 	//       1 = y
 	//         ^
 	line, col := src.Position(e.Pos)
-	srcLine := src.Input[src.Lines[line-1]:src.Lines[line]]
+	end := len(src.Input)
+	if len(src.Lines) > line {
+		end = src.Lines[line]
+	}
+	srcLine := src.Input[src.Lines[line-1]:end]
 	srcLine = strings.Replace(srcLine, "\t", " ", -1)
 	srcLine = strings.TrimRight(srcLine, "\n\r")
 	arrow := fmt.Sprintf("%*s", col, "^")

sem/resolve.go

@@ -41,6 +41,11 @@ func resolve(file *ast.File) error {
 
 	// First pass, add global declarations to file scope.
 	fileScope := NewScope(universe)
+	fileScope.IsDef = func(decl ast.Decl) bool {
+		// Consider variable declarations as tentative definitions; i.e. return
+		// false, unless variable definition.
+		return decl.Value() != nil
+	}
 	for _, decl := range file.Decls {
 		if err := fileScope.Insert(decl); err != nil {
 			return errutil.Err(err)

sem/scope.go

@@ -14,12 +14,18 @@ type Scope struct {
 	Outer *Scope
 	// Identifiers declared within the current scope.
 	Decls map[string]ast.Decl
+	// IsDef reports whether the given declaration is a definition.
+	IsDef func(ast.Decl) bool
 }
 
 // NewScope returns a new lexical scope immediately surrouded by the given outer
 // scope.
 func NewScope(outer *Scope) *Scope {
-	return &Scope{Outer: outer, Decls: make(map[string]ast.Decl)}
+	return &Scope{
+		Outer: outer,
+		Decls: make(map[string]ast.Decl),
+		IsDef: astutil.IsDef,
+	}
 }
 
 // Insert inserts the given declaration into the current scope.
@@ -50,13 +56,13 @@ func (s *Scope) Insert(decl ast.Decl) error {
 
 	// The last tentative definition becomes the definition, unless defined
 	// explicitly (e.g. having an initializer or function body).
-	if !astutil.IsDef(prev) {
+	if !s.IsDef(prev) {
 		s.Decls[name] = decl
 		return nil
 	}
 
 	// Definition already present in scope.
-	if astutil.IsDef(decl) {
+	if s.IsDef(decl) {
 		// TODO: Consider adding support for multiple errors (and potentially
 		// warnings and notifications).
 		//

sem/sem_test.go

@@ -17,33 +17,44 @@ func TestCheckValid(t *testing.T) {
 		path string
 	}{
 		{path: "../testdata/quiet/semantic/s01.c"},
-		{path: "../testdata/quiet/semantic/s02.c"},
 		{path: "../testdata/quiet/semantic/s03.c"},
 		{path: "../testdata/quiet/semantic/s04.c"},
 		{path: "../testdata/quiet/semantic/s05.c"},
 		{path: "../testdata/quiet/semantic/s06.c"},
 		{path: "../testdata/extra/semantic/missing-return-main.c"},
+		{path: "../testdata/extra/semantic/tentative-var-def.c"},
 		{path: "../testdata/extra/semantic/variable-sized-array-arg.c"},
 	}
 
+	errors.UseColor = false
+
 	for _, g := range golden {
-		s, err := scanner.Open(g.path)
+		buf, err := ioutil.ReadFile(g.path)
 		if err != nil {
-			t.Error(err)
+			t.Errorf("%q: %v", g.path, err)
 			continue
 		}
+		input := string(buf)
+		s := scanner.NewFromString(input)
+		src := errors.NewSource(g.path, input)
+
 		p := parser.NewParser()
 		file, err := p.Parse(s)
 		if err != nil {
 			t.Error(err)
 			continue
 		}
 		f := file.(*ast.File)
+
 		err = sem.Check(f)
 		if err != nil {
 			if e, ok := err.(*errutil.ErrInfo); ok {
 				// Unwrap errutil error.
 				err = e.Err
+				if e, ok := err.(*errors.Error); ok {
+					// Unwrap semantic error.
+					e.Src = src
+				}
 			}
 			t.Errorf("%q: unexpected error: `%v`", g.path, err.Error())
 		}
@@ -55,6 +66,12 @@ func TestCheckError(t *testing.T) {
 		path string
 		want string
 	}{
+		{
+			path: "../testdata/quiet/semantic/s02.c",
+			want: `(../testdata/quiet/semantic/s02.c:3) error: missing return at end of non-void function "foo"
+  ; }
+    ^`,
+		},
 		{
 			path: "../testdata/incorrect/semantic/se01.c",
 			want: `(../testdata/incorrect/semantic/se01.c:5) error: undeclared identifier "b"
@@ -278,12 +295,24 @@ void f(int a, void) {
 			want: `(../testdata/extra/semantic/index-array.c:7) error: invalid array index; expected integer, got "int[20]"
  x[y];
    ^`,
+		},
+		{
+			path: "../testdata/extra/semantic/local-var-redef.c",
+			want: `(../testdata/extra/semantic/local-var-redef.c:6) error: redefinition of "x"
+ int x;
+     ^`,
 		},
 		{
 			path: "../testdata/extra/semantic/missing-return.c",
 			want: `(../testdata/extra/semantic/missing-return.c:10) error: missing return at end of non-void function "f"
 }
 ^`,
+		},
+		{
+			path: "../testdata/extra/semantic/param-redef.c",
+			want: `(../testdata/extra/semantic/param-redef.c:5) error: redefinition of "x"
+ int x;
+     ^`,
 		},
 		{
 			path: "../testdata/extra/semantic/unnamed-arg.c",
@@ -296,12 +325,6 @@ void f(int) {
 			want: `(../testdata/extra/semantic/variable-sized-array.c:5) error: array size or initializer missing for "y"
  char y[];
       ^`,
-		},
-		{
-			path: "../testdata/extra/semantic/void-arg.c",
-			want: `(../testdata/extra/semantic/void-arg.c:4) error: "x" has invalid type "void"
-void f(void x) {
-            ^`,
 		},
 		{
 			path: "../testdata/extra/semantic/void-array.c",
@@ -313,6 +336,12 @@ void f(void x) {
 			path: "../testdata/extra/semantic/void-array-arg.c",
 			want: `(../testdata/extra/semantic/void-array-arg.c:4) error: invalid element type "void" of array "x"
 void f(void x[]) {
+            ^`,
+		},
+		{
+			path: "../testdata/extra/semantic/void-param.c",
+			want: `(../testdata/extra/semantic/void-param.c:4) error: "x" has invalid type "void"
+void f(void x) {
             ^`,
 		},
 		{
@@ -356,6 +385,7 @@ void f(void, void) {
 				// Unwrap errutil error.
 				err = e.Err
 				if e, ok := err.(*errors.Error); ok {
+					// Unwrap semantic error.
 					e.Src = src
 				}
 			}