[Relay] parser/pretty printer roundtripping (#3536)

python/tvm/relay/analysis.py

@@ -224,6 +224,20 @@ def alpha_equal(lhs, rhs):
     return bool(_make._alpha_equal(lhs, rhs))
 
 
+def assert_alpha_equal(lhs, rhs):
+    """Assert that two Relay expr is structurally equivalent. (alpha equivalence).
+
+    Parameters
+    ----------
+    lhs : tvm.relay.Expr
+        One of the input Expression.
+
+    rhs : tvm.relay.Expr
+        One of the input Expression.
+    """
+    _make._assert_alpha_equal(lhs, rhs)
+
+
 def graph_equal(lhs, rhs):
     """Compare two Relay expr for data-flow equivalence.
     The difference between this and alpha-equality is that
@@ -246,6 +260,23 @@ def graph_equal(lhs, rhs):
     return bool(_make._graph_equal(lhs, rhs))
 
 
+def assert_graph_equal(lhs, rhs):
+    """Compare two Relay expr for data-flow equivalence.
+    The difference between this and alpha-equality is that
+    variables are not expected to match between lhs and rhs;
+    they are treated as sources and are mapped between each other.
+
+    Parameters
+    ----------
+    lhs : tvm.relay.Expr
+      One of the input Expression.
+
+    rhs : tvm.relay.Expr
+      One of the input Expression.
+    """
+    _make._assert_graph_equal(lhs, rhs)
+
+
 def collect_device_info(expr):
     """Collect the device allocation map for the given expression. The device
     ids are propagated from the `device_copy` operators.

python/tvm/relay/grammar/Relay.g4

@@ -17,15 +17,20 @@
  * under the License.
  */
 
+// list = *, seq = ?
+
 grammar Relay;
 
 SEMVER: 'v0.0.3' ;
 
 // Lexing
 // comments
-WS : [ \t\n\r]+ -> skip ;
-LINE_COMMENT : '//' .*? '\n' -> skip ;
-COMMENT : '/*' .*? '*/' -> skip ;
+COMMENT : '/*' (COMMENT|.)*? '*/' -> skip;
+WS : [ \t\n\r]+ -> skip;
+LINE_COMMENT : '//' .*? '\n' -> skip;
+
+fragment ESCAPED_QUOTE : '\\"';
+QUOTED_STRING :   '"' ( ESCAPED_QUOTE | ~('\n'|'\r') )*? '"';
 
 // operators
 MUL: '*' ;
@@ -39,18 +44,18 @@ GE: '>=' ;
 EQ: '==' ;
 NE: '!=' ;
 
-opIdent: CNAME ;
-GLOBAL_VAR: '@' CNAME ;
-LOCAL_VAR: '%' CNAME;
-GRAPH_VAR: '%' NAT;
-
-MUT: 'mut' ;
-
 BOOL_LIT
   : 'True'
   | 'False'
   ;
 
+CNAME: ('_'|LETTER) ('_'|LETTER|DIGIT)* ('.' CNAME)*;
+opIdent: CNAME ;
+GLOBAL_VAR: '@' CNAME ;
+LOCAL_VAR: '%' CNAME;
+GRAPH_VAR: '%' NAT;
+
+DATATYPE : 'int64';
 // non-negative floats
 fragment PREFLOAT : NAT ('.' NAT)? EXP?; // 1.35, 1.35E-9, 0.3, 4.5, 1, 1e10 3e4
 
@@ -60,78 +65,69 @@ FLOAT : PREFLOAT 'f';
 NAT: DIGIT+ ;
 fragment EXP: [eE] [+\-]? NAT ; // \- since - means "range" inside [...]
 
-CNAME: ('_'|LETTER) ('_'|LETTER|DIGIT)* ;
-fragment LETTER: [a-zA-Z] ;
-fragment DIGIT: [0-9] ;
+fragment LETTER: [a-zA-Z];
+fragment DIGIT: [0-9];
 
+METADATA: 'METADATA:' .*;
 // Parsing
 
 // A Relay program is a list of global definitions or an expression.
-prog: SEMVER (defn* | expr) EOF ;
+prog: SEMVER (defn* | expr) METADATA? EOF ;
 
 // option: 'set' ident BOOL_LIT ;
 
+exprList: (expr (',' expr)*)?;
+callList
+  : exprList            # callNoAttr
+  | (expr ',')* attrSeq # callWithAttr
+  ;
+
 expr
   // operators
-  : '(' expr ')'                              # parens
+  : '(' expr ')'                              # paren
+  | '{' expr '}'                              # paren
   // function application
-  | expr '(' (expr (',' expr)*)? ')'          # call
+  | expr '(' callList ')'                     # call
   | '-' expr                                  # neg
   | expr op=('*'|'/') expr                    # binOp
   | expr op=('+'|'-') expr                    # binOp
   | expr op=('<'|'>'|'<='|'>=') expr          # binOp
   | expr op=('=='|'!=') expr                  # binOp
-
   // function definition
   | func                                      # funcExpr
-
   // tuples and tensors
   | '(' ')'                                   # tuple
   | '(' expr ',' ')'                          # tuple
   | '(' expr (',' expr)+ ')'                  # tuple
+  | expr '.' NAT                              # projection
   | '[' (expr (',' expr)*)? ']'               # tensor
-
   | 'if' '(' expr ')' body 'else' body        # ifElse
-
   // sequencing
-  | 'let' MUT? var '=' expr ';' expr          # let
-  | 'let' MUT? var '=' '{' expr '}' ';' expr  # let
+  | 'let' var '=' expr ';' expr               # let
   // sugar for let %_ = expr; expr
-  | expr ';' expr                             # let
-  | ident '=' expr ';' expr                   # graph
-
-  // mutable update
-  // | ident '=' expr                            # writeRef
-  // | expr '^'                                  # readRef
-
+  | expr ';;' expr                            # let
+  | GRAPH_VAR '=' expr ';' expr               # graph
   | ident                                     # identExpr
   | scalar                                    # scalarExpr
-  // | expr '.' NAT                           # project
-  // | 'debug'                                # debug
+  | meta                                      # metaExpr
+  | QUOTED_STRING                             # stringExpr
   ;
 
-func: 'fn'        typeParamSeq? '(' argList ')' ('->' type_)? body ;
-defn: 'def' ident typeParamSeq? '(' argList ')' ('->' type_)? body ;
+func: 'fn'        typeParamList? '(' argList ')' ('->' type_)? body ;
+defn: 'def' ident typeParamList? '(' argList ')' ('->' type_)? body ;
 
 argList
-  : varList
-  | attrList
-  | varList ',' attrList
+  : varList              # argNoAttr
+  | (var ',')* attrSeq   # argWithAttr
   ;
 
-varList: (var (',' var)*)? ;
-var: ident (':' type_)? ;
+varList: (var (',' var)*)?;
+var: LOCAL_VAR (':' type_)?;
 
-attrList: (attr (',' attr)*)? ;
+attrSeq: attr (',' attr)*;
 attr: CNAME '=' expr ;
 
-// TODO(@jmp): for improved type annotations
-// returnAnno: (ident ':')? type_ ;
-
-// relations: 'where' relation (',' relation)* ;
-// relation: ident '(' (type_ (',' type_)*)? ')' ;
-
-typeParamSeq
+typeParamList
   : '[' ']'
   | '[' ident (',' ident)* ']'
   ;
@@ -141,28 +137,27 @@ type_
   | '(' type_ ',' ')'                                            # tupleType
   | '(' type_ (',' type_)+ ')'                                   # tupleType
   | typeIdent                                                    # typeIdentType
-  | 'Tensor' '[' shapeSeq ',' type_ ']'             # tensorType
-  // currently unused
-  // | typeIdent '[' (type_ (',' type_)*)? ']'         # callType
-  | 'fn' typeParamSeq? '(' (type_ (',' type_)*)? ')' '->' type_   # funcType
+  | 'Tensor' '[' shapeList ',' type_ ']'                         # tensorType
+  | 'fn' typeParamList? '(' (type_ (',' type_)*)? ')' '->' type_ # funcType
   | '_'                                                          # incompleteType
   | NAT                                                          # intType
   ;
 
-shapeSeq
-  : '(' ')'
-  | '(' shape ',' ')'
-  | '(' shape (',' shape)+ ')'
+shapeList
+  : '(' shape (',' shape)+ ')'
+  | '(' ')'
+  | shape
   ;
 
+meta : 'meta' '[' CNAME ']' '[' NAT ']';
+
 shape
-  : '(' shape ')'                   # parensShape
-  // | type_ op=('*'|'/') type_        # binOpType
-  // | type_ op=('+'|'-') type_        # binOpType
+  : meta # metaShape
+  | '(' shape ')'                        # parensShape
   | NAT                                  # intShape
   ;
 
-typeIdent : CNAME ;
+typeIdent : CNAME;
 // int8, int16, int32, int64
 // uint8, uint16, uint32, uint64
 // float16, float32, float64

python/tvm/relay/grammar/py3/RelayVisitor.py

@@ -19,11 +19,51 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
+    # Visit a parse tree produced by RelayParser#exprList.
+    def visitExprList(self, ctx:RelayParser.ExprListContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#callNoAttr.
+    def visitCallNoAttr(self, ctx:RelayParser.CallNoAttrContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#callWithAttr.
+    def visitCallWithAttr(self, ctx:RelayParser.CallWithAttrContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#funcExpr.
+    def visitFuncExpr(self, ctx:RelayParser.FuncExprContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#metaExpr.
+    def visitMetaExpr(self, ctx:RelayParser.MetaExprContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#tensor.
+    def visitTensor(self, ctx:RelayParser.TensorContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#graph.
+    def visitGraph(self, ctx:RelayParser.GraphContext):
+        return self.visitChildren(ctx)
+
+
     # Visit a parse tree produced by RelayParser#identExpr.
     def visitIdentExpr(self, ctx:RelayParser.IdentExprContext):
         return self.visitChildren(ctx)
 
 
+    # Visit a parse tree produced by RelayParser#stringExpr.
+    def visitStringExpr(self, ctx:RelayParser.StringExprContext):
+        return self.visitChildren(ctx)
+
+
     # Visit a parse tree produced by RelayParser#call.
     def visitCall(self, ctx:RelayParser.CallContext):
         return self.visitChildren(ctx)
@@ -39,13 +79,8 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#parens.
-    def visitParens(self, ctx:RelayParser.ParensContext):
-        return self.visitChildren(ctx)
-
-
-    # Visit a parse tree produced by RelayParser#funcExpr.
-    def visitFuncExpr(self, ctx:RelayParser.FuncExprContext):
+    # Visit a parse tree produced by RelayParser#paren.
+    def visitParen(self, ctx:RelayParser.ParenContext):
         return self.visitChildren(ctx)
 
 
@@ -59,8 +94,8 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#tensor.
-    def visitTensor(self, ctx:RelayParser.TensorContext):
+    # Visit a parse tree produced by RelayParser#projection.
+    def visitProjection(self, ctx:RelayParser.ProjectionContext):
         return self.visitChildren(ctx)
 
 
@@ -69,11 +104,6 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#graph.
-    def visitGraph(self, ctx:RelayParser.GraphContext):
-        return self.visitChildren(ctx)
-
-
     # Visit a parse tree produced by RelayParser#binOp.
     def visitBinOp(self, ctx:RelayParser.BinOpContext):
         return self.visitChildren(ctx)
@@ -89,8 +119,13 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#argList.
-    def visitArgList(self, ctx:RelayParser.ArgListContext):
+    # Visit a parse tree produced by RelayParser#argNoAttr.
+    def visitArgNoAttr(self, ctx:RelayParser.ArgNoAttrContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#argWithAttr.
+    def visitArgWithAttr(self, ctx:RelayParser.ArgWithAttrContext):
         return self.visitChildren(ctx)
 
 
@@ -104,8 +139,8 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#attrList.
-    def visitAttrList(self, ctx:RelayParser.AttrListContext):
+    # Visit a parse tree produced by RelayParser#attrSeq.
+    def visitAttrSeq(self, ctx:RelayParser.AttrSeqContext):
         return self.visitChildren(ctx)
 
 
@@ -114,8 +149,8 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#typeParamSeq.
-    def visitTypeParamSeq(self, ctx:RelayParser.TypeParamSeqContext):
+    # Visit a parse tree produced by RelayParser#typeParamList.
+    def visitTypeParamList(self, ctx:RelayParser.TypeParamListContext):
         return self.visitChildren(ctx)
 
 
@@ -149,8 +184,18 @@ class RelayVisitor(ParseTreeVisitor):
         return self.visitChildren(ctx)
 
 
-    # Visit a parse tree produced by RelayParser#shapeSeq.
-    def visitShapeSeq(self, ctx:RelayParser.ShapeSeqContext):
+    # Visit a parse tree produced by RelayParser#shapeList.
+    def visitShapeList(self, ctx:RelayParser.ShapeListContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#meta.
+    def visitMeta(self, ctx:RelayParser.MetaContext):
+        return self.visitChildren(ctx)
+
+
+    # Visit a parse tree produced by RelayParser#metaShape.
+    def visitMetaShape(self, ctx:RelayParser.MetaShapeContext):
         return self.visitChildren(ctx)
 
 

python/tvm/relay/op/nn/nn.py

@@ -66,34 +66,34 @@ def conv2d(data,
     weight : tvm.relay.Expr
         The weight expressions.
 
-    strides : tuple of int, optional
+    strides : Optional[Tuple[int]]
         The strides of convolution.
 
-    padding : tuple of int, optional
+    padding : Optional[Tuple[int]]
         The padding of convolution on both sides of inputs before convolution.
 
-    dilation : tuple of int, optional
+    dilation : Optional[Tuple[int]]
         Specifies the dilation rate to be used for dilated convolution.
 
-    groups : int, optional
+    groups : Optional[int]
         Number of groups for grouped convolution.
 
-    channels : int, optional
+    channels : Optional[int]
         Number of output channels of this convolution.
 
-    kernel_size : tuple of int, optional
+    kernel_size : Optional[Tuple[int]]
         The spatial of the convolution kernel.
 
-    data_layout : str, optional
+    data_layout : Optional[str]
         Layout of the input.
 
-    kernel_layout : str, optional
+    kernel_layout : Optional[str]
         Layout of the weight.
 
-    out_layout : str, optional
+    out_layout : Optional[str]
         Layout of the output, by default, out_layout is the same as data_layout
 
-    out_dtype : str, optional
+    out_dtype : Optional[str]
         Specifies the output data type for mixed precision conv2d.
 
     Returns
@@ -691,8 +691,30 @@ def dropout(data, rate=0.5):
     result : tvm.relay.Expr
         The result of dropout
     """
-    result = _make.dropout(data, rate)
-    return TupleWrapper(result, 2)[0]
+    return TupleWrapper(dropout_raw(data, rate), 2)[0]
+
+
+def dropout_raw(data, rate=0.5):
+    """Applies the dropout operation to the input array.
+
+    During training, each element of the input is set to zero with
+    probability ``p``. The whole array is rescaled by ``1/(1-p)``
+    to keep the expected sum of the input unchanged.
+
+    Parameters
+    ----------
+    data : tvm.relay.Expr
+        The input data to the operator.
+
+    rate : float, optional (default=0.5)
+        The probability for an element to be reset to 0.
+
+    Returns
+    -------
+    result : tvm.relay.Expr
+        The result of dropout
+    """
+    return _make.dropout(data, rate)
 
 
 def batch_norm(data,

python/tvm/relay/parser.py

@@ -23,4 +23,7 @@ from .. import register_func
 def fromtext(data, source_name=None):
     """Parse a Relay program."""
     from tvm.relay import _parser
-    return _parser.fromtext(data, source_name)
+    x = _parser.fromtext(data + "\n", source_name)
+    if x is None:
+        raise Exception("cannot parse: ", data)
+    return x

python/tvm/relay/testing/densenet.py

@@ -42,7 +42,7 @@ def _make_dense_block(data, num_layers, bn_size, growth_rate, index):
     layer_out = data
     for i in range(num_layers):
         layer_out = _make_dense_layer(layer_out, growth_rate, bn_size,
-                                      "(%s, %s)" % (index, i))
+                                      "%s_%s" % (index, i))
     return layer_out
 
 def _make_transition(data, num_output_features, index):

python/tvm/relay/ty.py

@@ -29,7 +29,7 @@ class Type(RelayNode):
         """Compare two Relay types for structural equivalence using
            alpha equivalence.
         """
-        return bool(_make._type_alpha_equal(self, other))
+        return bool(_make._alpha_equal(self, other))
 
     def __ne__(self, other):
         return not self.__eq__(other)

src/relay/ir/alpha_equal.cc

@@ -18,7 +18,7 @@
  */
 
 /*!
- *  Copyright (c) 2018 by Contributors
+ *  Copyright (c) 2019 by Contributors
  * \file src/tvm/relay/ir/alpha_equal.cc
  * \brief Alpha equality check by deep comparing two nodes.
  */
@@ -27,9 +27,10 @@
 #include <tvm/relay/pattern_functor.h>
 #include <tvm/runtime/ndarray.h>
 #include <tvm/relay/analysis.h>
+#include <tvm/relay/op_attr_types.h>
+#include <tvm/relay/attrs/nn.h>
 #include "type_functor.h"
 #include "../../lang/attr_functor.h"
-
 namespace tvm {
 namespace relay {
 
@@ -40,8 +41,8 @@ class AlphaEqualHandler:
       public ExprFunctor<bool(const Expr&, const Expr&)>,
       public PatternFunctor<bool(const Pattern&, const Pattern&)> {
  public:
-  explicit AlphaEqualHandler(bool map_free_var)
-    : map_free_var_(map_free_var) { }
+  explicit AlphaEqualHandler(bool map_free_var, bool assert_mode)
+    : map_free_var_(map_free_var), assert_mode_(assert_mode) { }
 
   /*!
    * Check equality of two nodes.
@@ -76,6 +77,9 @@ class AlphaEqualHandler:
     return AttrEqual(lhs, rhs);
   }
 
+  bool DoubleEqual(double l, double r) {
+    return true;
+  }
   /*!
    * Check equality of two attributes.
    * \param lhs The left hand operand.
@@ -83,9 +87,9 @@ class AlphaEqualHandler:
    * \return The comparison result.
    */
   bool AttrEqual(const NodeRef& lhs, const NodeRef& rhs) {
+    auto compute = [&]() {
       if (&lhs == &rhs) return true;
-    auto lhsd = lhs.as<DictAttrsNode>();
-    if (lhsd) {
+      if (auto lhsd = lhs.as<DictAttrsNode>()) {
         auto rhsd = lhs.as<DictAttrsNode>();
         if (!rhsd) return false;
         if (lhsd->dict.size() != rhsd->dict.size()) return false;
@@ -94,7 +98,17 @@ class AlphaEqualHandler:
         }
         return true;
       }
+      if (auto lhsbn = lhs.as<BatchNormAttrs>()) {
+        auto rhsbn = rhs.as<BatchNormAttrs>();
+        if (!rhsbn) return false;
+        return (lhsbn->axis == rhsbn->axis)
+          && DoubleEqual(lhsbn->epsilon, rhsbn->epsilon)
+          && (lhsbn->center == rhsbn->center)
+          && (lhsbn->scale == rhsbn->scale);
+      }
       return AttrsEqualHandler::Equal(lhs, rhs);
+    };
+    return Compare(compute(), lhs, rhs);
   }
   /*!
    * Check equality of two types.
@@ -107,6 +121,13 @@ class AlphaEqualHandler:
     if (!lhs.defined() || !rhs.defined()) return false;
     return this->VisitType(lhs, rhs);
   }
+
+  bool Compare(bool result, const NodeRef& lhs, const NodeRef& rhs) {
+    if (assert_mode_) {
+      CHECK(result) << "\n" << AsText(lhs, true) << "\nis not equal to:\n" << AsText(rhs, true);
+    }
+    return result;
+  }
   /*!
    * Check equality of two expressions.
    *
@@ -120,6 +141,7 @@ class AlphaEqualHandler:
    * \return The comparison result.
    */
   bool ExprEqual(const Expr& lhs, const Expr& rhs) {
+    auto compute = [&]() {
       if (lhs.same_as(rhs)) return true;
       if (!lhs.defined() || !rhs.defined()) return false;
       auto it = equal_map_.find(lhs);
@@ -132,6 +154,8 @@ class AlphaEqualHandler:
       } else {
         return false;
       }
+    };
+    return Compare(compute(), lhs, rhs);
   }
 
  protected:
@@ -516,32 +540,41 @@ class AlphaEqualHandler:
  private:
   // whether to map open terms.
   bool map_free_var_;
+  // if in assert mode, must return true, and will throw error otherwise.
+  bool assert_mode_;
   // renaming of NodeRef to indicate two nodes equals to each other
   std::unordered_map<NodeRef, NodeRef, NodeHash, NodeEqual> equal_map_;
 };
 
 bool AlphaEqual(const Type& lhs, const Type& rhs) {
-  return AlphaEqualHandler(false).TypeEqual(lhs, rhs);
+  return AlphaEqualHandler(false, false).TypeEqual(lhs, rhs);
 }
 
 bool AlphaEqual(const Expr& lhs, const Expr& rhs) {
-  return AlphaEqualHandler(false).ExprEqual(lhs, rhs);
+  return AlphaEqualHandler(false, false).ExprEqual(lhs, rhs);
 }
 
 // TODO(@jroesch): move to correct namespace?
 TVM_REGISTER_API("relay._make._alpha_equal")
 .set_body_typed<bool(NodeRef, NodeRef)>([](NodeRef a, NodeRef b) {
-  return AlphaEqualHandler(false).Equal(a, b);
+  return AlphaEqualHandler(false, false).Equal(a, b);
 });
 
-TVM_REGISTER_API("relay._make._type_alpha_equal")
-.set_body_typed<bool(Type, Type)>([](Type a, Type b) {
-  return AlphaEqualHandler(false).TypeEqual(a, b);
+TVM_REGISTER_API("relay._make._assert_alpha_equal")
+.set_body_typed<void(NodeRef, NodeRef)>([](NodeRef a, NodeRef b) {
+  bool alpha_equal = AlphaEqualHandler(false, true).Equal(a, b);
+  CHECK(alpha_equal) << AsText(a, true) << " and " << AsText(b, true) << " is not alpha equal";
 });
 
 TVM_REGISTER_API("relay._make._graph_equal")
 .set_body_typed<bool(NodeRef, NodeRef)>([](NodeRef a, NodeRef b) {
-  return AlphaEqualHandler(true).Equal(a, b);
+  return AlphaEqualHandler(true, false).Equal(a, b);
+});
+
+TVM_REGISTER_API("relay._make._assert_graph_equal")
+.set_body_typed<void(NodeRef, NodeRef)>([](NodeRef a, NodeRef b) {
+  bool graph_equal = AlphaEqualHandler(true, true).Equal(a, b);
+  CHECK(graph_equal) << AsText(a, true) << " and " << AsText(b, true) << " is not graph equal";
 });
 
 }  // namespace relay

src/relay/ir/doc.cc

@@ -89,7 +89,7 @@ std::string Doc::str() {
   return os.str();
 }
 
-Doc PrintVec(const std::vector<Doc>& vec, const Doc& sep) {
+Doc PrintSep(const std::vector<Doc>& vec, const Doc& sep) {
   Doc seq;
   if (vec.size() != 0) {
     seq = vec[0];

src/relay/ir/doc.h

@@ -46,7 +46,11 @@ using DocAtom = std::shared_ptr<DocAtomNode>;
 struct TextNode : DocAtomNode {
   std::string str;
 
-  explicit TextNode(const std::string& str) : str(str) {}
+  explicit TextNode(const std::string& str) : str(str) {
+    if (str.find_first_of("\t\n") != str.npos) {
+      LOG(WARNING) << "text node: '" << str << "' should not has tab or newline.";
+    }
+  }
 };
 
 struct LineNode : DocAtomNode {
@@ -91,8 +95,8 @@ class Doc {
 
 // DSL functions
 
-// Render vectors of docs with a separator. e.g. PrintVec([1, 2, 3], f) -> 1f2f3
-Doc PrintVec(const std::vector<Doc>& vec, const Doc& sep = Doc(", "));
+// Render vectors of docs with a separator. e.g. PrintSep([1, 2, 3], f) -> 1f2f3
+Doc PrintSep(const std::vector<Doc>& vec, const Doc& sep = Doc(", "));
 // Print a constant bool value.
 Doc PrintBool(bool value);
 // Print a data type.
@@ -116,7 +120,8 @@ Doc PrintConstScalar(DataType dtype, const T* data) {
   } else if (dtype == Bool()) {
     return PrintBool(data[0] != 0);
   } else {
-    os << dtype << "(" << data[0] << ")";
+    // todo(@M.K.) this is unsafe. fix.
+    os << data[0];
   }
   return Doc(os.str());
 }

src/relay/ir/pretty_printer.cc

@@ -32,6 +32,7 @@
  *  - Otherwise, inline if the node is at the end of a scope and is used at most once.
  */
 
+#include <dmlc/json.h>
 #include <tvm/relay/expr_functor.h>
 #include <tvm/relay/module.h>
 #include <tvm/relay/pattern_functor.h>
@@ -43,6 +44,17 @@
 namespace tvm {
 namespace relay {
 
+Doc Brace(const Doc& d,
+          const std::string& open = "{",
+          const std::string& close = "}",
+          int indent = 2) {
+  Doc doc;
+  doc << open;
+  doc << Indent(indent, PrintNewLine() << d) << PrintNewLine();
+  doc << close;
+  return doc;
+}
+
 /*!
  * \brief Meta data context for PrettyPrinter.
  *
@@ -108,8 +120,10 @@ class TextMetaDataContext {
     if (it != meta_repr_.end()) {
       return it->second;
     }
+    std::string type_key = node->type_key();
+    CHECK(!type_key.empty());
     Array<NodeRef>& mvector =
-        meta_data_[node->type_key()];
+        meta_data_[type_key];
     int64_t index = static_cast<int64_t>(mvector.size());
     mvector.push_back(node);
     Doc doc;
@@ -117,14 +131,18 @@ class TextMetaDataContext {
     meta_repr_[node] = doc;
     return meta_repr_[node];
   }
+
+  Doc PrintKeyValue(const std::string& str, const Doc& v) const {
+    return Doc("\"") << str << "\": " << v;
+  }
+
   /*!
    * \brief Get the metadata section in json format.
    * \return the meta data string.
    */
-  std::string GetMetaSection() const {
-    if (meta_data_.size() == 0) return std::string();
-    return SaveJSON(Map<std::string, NodeRef>(
-        meta_data_.begin(), meta_data_.end()));
+  Doc GetMetaSection() const {
+    if (meta_data_.size() == 0) return Doc();
+    return Doc(SaveJSON(Map<std::string, NodeRef>(meta_data_.begin(), meta_data_.end())));
   }
 
   /*! \return whether the meta data context is empty. */
@@ -172,12 +190,11 @@ class PrettyPrinter :
   }
 
   // indent a new body
-  // TODO(jmp): indent should be an instance variable of the printer
   Doc PrintBody(const NodeRef& node, int indent = 2) {
     Doc doc;
     Doc body;
     doc << "{";
-    doc << Indent(indent, body << "\n" << PrintScope(node)) << "\n";
+    doc << Indent(indent, body << PrintNewLine() << PrintScope(node)) << PrintNewLine();
     doc << "}";
     return doc;
   }
@@ -203,13 +220,12 @@ class PrettyPrinter :
     Doc doc;
     doc << PrintScope(node);
     if (!meta_.empty()) {
+      doc << PrintNewLine();
       if (show_meta_data_) {
-        std::string meta_json = meta_.GetMetaSection();
         // append meta data in the end.
-        doc << "\n" << "/* meta data */" << "\n" << meta_json;
+        doc << "METADATA:" << PrintNewLine() << meta_.GetMetaSection();
       } else {
-        doc << "\n"
-            << "// meta data omitted. you can use show_meta_data=True to include meta data";
+        doc << "// meta data omitted. you can use show_meta_data=True to include meta data";
       }
     }
     return doc;
@@ -361,7 +377,7 @@ class PrettyPrinter :
       // wrap GNFed let in brackets
       Doc body;
       printed_expr << "{";
-      printed_expr << Indent(2, body << "\n" << VisitExpr(expr)) << "\n";
+      printed_expr << Indent(2, body << PrintNewLine() << VisitExpr(expr)) << PrintNewLine();
       printed_expr << "}";
     } else {
       printed_expr = VisitExpr(expr);
@@ -373,7 +389,7 @@ class PrettyPrinter :
     if (expr.as<VarNode>()) {
       // This is our first time visiting the var and we hit the VarNode case
       // in the visitor. Thus the variable is free.
-      doc_stack_.back() << "free_var " << printed_expr << "\n";
+      doc_stack_.back() << "free_var " << printed_expr << PrintNewLine();
       // Memoization is done in AllocVar.
       return memo_[expr];
     } else if (inline_expr) {
@@ -422,7 +438,7 @@ class PrettyPrinter :
       fields.push_back(Print(field));
     }
     Doc doc;
-    doc << "(" << PrintVec(fields);
+    doc << "(" << PrintSep(fields);
     // conform to python tuple format (1,)
     if (op->fields.size() == 1) {
       doc << ",";
@@ -468,7 +484,7 @@ class PrettyPrinter :
       for (const TypeVar& tv : fn->type_params) {
         type_params.push_back(AllocTypeVar(tv));
       }
-        doc << PrintVec(type_params);
+      doc << PrintSep(type_params);
       doc << ">";
     }
     doc << "(";
@@ -479,7 +495,7 @@ class PrettyPrinter :
     for (const Doc& d : PrintFuncAttrs(fn->attrs)) {
       params.push_back(d);
     }
-      doc << PrintVec(params) << ") ";
+    doc << PrintSep(params) << ") ";
     if (fn->ret_type.defined()) {
       doc << "-> " << Print(fn->ret_type) << " ";
     }
@@ -493,13 +509,13 @@ class PrettyPrinter :
     for (const auto& kv : mod->functions) {
       dg_ = DependencyGraph::Create(&arena_, kv.second);
 
-      std::ostringstream os;
       if (counter++ != 0) {
-        doc << "\n";
+        doc << PrintNewLine();
       }
+      std::ostringstream os;
       os << "def @" << kv.first->name_hint;
       doc << PrintFunc(Doc(os.str()), kv.second);
-      doc << "\n";
+      doc << PrintNewLine();
     }
     return doc;
   }
@@ -528,7 +544,7 @@ class PrettyPrinter :
       args.push_back(d);
     }
     doc << Print(op->op);
-    return doc << "(" << PrintVec(args) << ")";
+    return doc << "(" << PrintSep(args) << ")";
   }
 
   Doc VisitExpr_(const RefCreateNode* op) final {
@@ -558,7 +574,7 @@ class PrettyPrinter :
       clauses.push_back(clause_doc << Print(clause->lhs) << " -> "
                                    << Print(clause->rhs));
     }
-    doc << Indent(2, body << "\n" << PrintVec(clauses, Doc("\n"))) << "\n";
+    doc << Indent(2, body << PrintNewLine() << PrintSep(clauses, PrintNewLine())) << PrintNewLine();
     doc << "}";
     return doc;
   }
@@ -570,7 +586,7 @@ class PrettyPrinter :
     for (const auto& pat : p->patterns) {
       pats.push_back(Print(pat));
     }
-    return doc << PrintVec(pats) << ")";
+    return doc << PrintSep(pats) << ")";
   }
 
   Doc VisitPattern_(const PatternVarNode* pv) final {
@@ -617,7 +633,7 @@ class PrettyPrinter :
       args.push_back(PrintType(t, false));
     }
     doc << "[";
-    doc << PrintVec(args);
+    doc << PrintSep(args);
     doc << "]";
     return doc;
   }
@@ -633,11 +649,7 @@ class PrettyPrinter :
     for (NodeRef shape : node->shape) {
       shapes.push_back(PrintAttr(shape));
     }
-    doc << PrintVec(shapes);
-    // conform to python tuple format (1,)
-    if (node->shape.size() == 1) {
-      doc << ",";
-    }
+    doc << PrintSep(shapes);
     return doc << "), " << PrintDType(node->dtype) << "]";
   }
 
@@ -647,7 +659,7 @@ class PrettyPrinter :
       fields.push_back(Print(field));
     }
     Doc doc;
-    doc << "(" << PrintVec(fields);
+    doc << "(" << PrintSep(fields);
     // conform to python tuple format (1,)
     if (node->fields.size() == 1) {
       doc << ",";
@@ -664,14 +676,14 @@ class PrettyPrinter :
       for (Type type_param : node->type_params) {
         type_params.push_back(Print(type_param));
       }
-      doc << PrintVec(type_params);
+      doc << PrintSep(type_params);
       doc << ">";
     }
     std::vector<Doc> arg_types;
     for (Type arg_type : node->arg_types) {
       arg_types.push_back(Print(arg_type));
     }
-    return doc << "(" << PrintVec(arg_types) << ") -> " << Print(node->ret_type);
+    return doc << "(" << PrintSep(arg_types) << ") -> " << Print(node->ret_type);
   }
 
   Doc VisitType_(const RefTypeNode* node) final {
@@ -710,7 +722,7 @@ class PrettyPrinter :
     for (NodePtr<Node> val : op->data) {
       arr_vals.push_back(PrintAttr(NodeRef(val)));
     }
-    doc << PrintVec(arr_vals);
+    doc << PrintSep(arr_vals);
     doc << "]";
     return doc;
   }
@@ -771,7 +783,9 @@ class PrettyPrinter::AttrPrinter : public AttrVisitor {
   }
 
   void Visit(const char* key, double* value) final {
-    PrintKV(key, *value);
+    Doc doc;
+    doc << key << "=" << *value << "f";
+    docs->push_back(doc);
   }
   void Visit(const char* key, int64_t* value) final {
     PrintKV(key, *value);
@@ -843,7 +857,7 @@ std::string PrettyPrint_(const NodeRef& node,
                          bool show_meta_data,
                          runtime::TypedPackedFunc<std::string(Expr)> annotate) {
   Doc doc;
-  doc << "v0.0.3" << "\n"
+  doc << "v0.0.3" << PrintNewLine()
       << PrettyPrinter(show_meta_data, annotate).PrintFinal(node);
   return doc.str();
 }

tests/python/relay/test_ir_parser.py

@@ -16,7 +16,7 @@
 # under the License.
 import tvm
 from tvm import relay
-from tvm.relay.analysis import alpha_equal
+from tvm.relay.analysis import alpha_equal, assert_alpha_equal
 from nose.tools import nottest, raises
 from numpy import isclose
 from typing import Union
@@ -60,12 +60,9 @@ TYPES = {
     "float16x4",
 }
 
-def assert_alpha_equal(a, b):
-    if not alpha_equal(a, b):
-        raise Exception("lhs is: ", str(a), "rhs is: ", str(b))
-
 def roundtrip(expr):
-    assert_alpha_equal(relay.fromtext(str(expr)), expr)
+    x = relay.fromtext(str(expr))
+    assert_alpha_equal(x, expr)
 
 
 def parse_text(code):
@@ -112,6 +109,16 @@ def test_comments():
         UNIT
     )
 
+    assert parses_as(
+        """
+        /* This is a block comment!
+           /*Block comment is recursive!*/
+        */
+        ()
+        """,
+        UNIT
+    )
+
 
 def test_int_literal():
     assert isinstance(parse_text("1"), relay.Constant)
@@ -224,7 +231,7 @@ def test_let():
 
 def test_seq():
     assert parses_as(
-        "(); ()",
+        "();; ()",
         relay.Let(
             _,
             UNIT,
@@ -538,7 +545,7 @@ def test_tensor_type():
     )
 
     assert parses_as(
-        "let %_ : Tensor[(1,), float32] = (); ()",
+        "let %_ : Tensor[(1), float32] = (); ()",
         relay.Let(
             relay.Var("_", relay.TensorType((1,), "float32")),
             UNIT,

tests/python/relay/test_ir_text_printer.py

@@ -15,14 +15,27 @@
 # specific language governing permissions and limitations
 # under the License.
 import tvm
+from tvm import relay
 import tvm.relay.testing
 import numpy as np
-from tvm import relay
+from tvm.relay import Expr
+from tvm.relay.analysis import alpha_equal, assert_alpha_equal, assert_graph_equal, free_vars
 
 do_print = [False]
 
 SEMVER = "v0.0.3\n"
 
+def astext(p, graph_equal=False):
+    txt = p.astext()
+    if isinstance(p, Expr) and free_vars(p):
+        return txt
+    x = relay.fromtext(txt)
+    if graph_equal:
+        assert_graph_equal(x, p)
+    else:
+        assert_alpha_equal(x, p)
+    return txt
+
 def show(text):
     if do_print[0]:
         print("---------------------------")
@@ -35,8 +48,8 @@ def test_func():
     z = relay.add(x, one)
     z = relay.add(z, z)
     f = relay.Function([x, y], z)
-    show(z.astext())
-    show(f.astext())
+    show(astext(z))
+    show(astext(f))
 
 
 def test_env():
@@ -47,7 +60,7 @@ def test_env():
     f = relay.Function([x, y], z)
     env = relay.Module()
     env["myf"] = f
-    text = env.astext()
+    text = astext(env)
     assert "def @myf" in text
     assert "def @myf" in str(env)
     assert "add(%0, %0) /* ty=float32 */" in text
@@ -65,7 +78,7 @@ def test_meta_data():
                         padding=(1, 1),
                         channels=2)
     f = relay.Function([x, w], z)
-    text = f.astext()
+    text = astext(f, graph_equal=True)
     text_no_meta = str(f)
     assert "channels=2" in text
     assert "channels=2" in text_no_meta
@@ -73,25 +86,22 @@ def test_meta_data():
     assert "meta[Variable][0]" in text_no_meta
     assert "type_key" in text
     assert "type_key" not in text_no_meta
-    show(text)
-    show(f)
 
-    text = relay.const([1,2,3]).astext()
+    text = astext(relay.const([1,2,3]))
     assert "meta[relay.Constant][0]" in text
-    show(text)
 
 
 def test_call_attrs():
     x = relay.var("x")
     # non default args
     z = relay.nn.softmax(x, axis=2)
-    assert "axis=2" in z.astext()
+    assert "axis=2" in astext(z)
     # default args
     z = relay.nn.softmax(x)
-    assert "softmax(%x)" in z.astext()
+    assert "softmax(%x)" in astext(z)
     # non default args
     z = relay.expand_dims(x, axis=2, num_newaxis=2)
-    assert "num_newaxis=2" in z.astext()
+    assert "num_newaxis=2" in astext(z)
 
 
 def test_let_if_scope():
@@ -111,68 +121,72 @@ def test_let_if_scope():
     result = sb.get()
 
     f = relay.Function([x, y, cond], result)
-    text = f.astext()
+    text = astext(f)
     assert text.count("{") == 4
     assert "%cond: bool" in text
-    show(f.astext())
+    show(astext(f))
 
 
 def test_variable_name():
     # avoid pure number even if the namehint is pure number
     v1 = relay.var("1")
-    assert "%v1" in v1.astext()
+    assert "%v1" in astext(v1)
 
 
 def test_mlp():
     net, params = tvm.relay.testing.mlp.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 
 def test_resnet():
     net, params = tvm.relay.testing.resnet.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 
 def test_mobilenet():
     net, params = tvm.relay.testing.mobilenet.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 
 def test_dqn():
     net, params = tvm.relay.testing.dqn.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 
 def test_dcgan():
     net, params = tvm.relay.testing.dcgan.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 
 def test_lstm():
+    net, params = tvm.relay.testing.lstm.get_workload(1, 1)
+    astext(net)
+
     net, params = tvm.relay.testing.lstm.get_workload(4, 4)
-    net.astext()
+    astext(net)
 
 def test_inception_v3():
     net, params = tvm.relay.testing.inception_v3.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 def test_squeezenet():
     for version in ['1.0', '1.1']:
         net, params = tvm.relay.testing.squeezenet.get_workload(batch_size=1, version=version)
-        net.astext()
+        astext(net)
 
 def test_vgg():
     net, params = tvm.relay.testing.vgg.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 def test_densenet():
     net, params = tvm.relay.testing.densenet.get_workload(batch_size=1)
-    net.astext()
+    astext(net)
 
 def test_call_node_order():
     x = relay.var("x")
     y = relay.var("y")
-    assert relay.Call(relay.Function([x], x), [relay.Call(relay.Function([y], y), [relay.const(1)])]).astext() == SEMVER + \
+    prog = relay.Call(relay.Function([x], x), [relay.Call(relay.Function([y], y), [relay.const(1)])])
+    assert astext(prog) == SEMVER + \
         ("%0 = fn (%y) {\n"
          "  %y\n"
          "};\n"
@@ -185,17 +199,25 @@ def test_call_node_order():
 def test_let_inlining():
     tup = relay.Tuple([relay.const(0), relay.const(0)])
     x = relay.var("x")
-    assert relay.Let(x, tup, tup).astext() == SEMVER + \
+    assert astext(relay.Let(x, tup, tup)) == SEMVER + \
         ("%0 = (0, 0);\n"
          "let %x = %0;\n"
          "%0")
 
-    assert relay.Let(x, tup, x).astext() == SEMVER + \
+    assert astext(relay.Let(x, tup, x)) == SEMVER + \
         ("let %x = (0, 0);\n"
          "%x")
 
+def test_zeros():
+    x = relay.op.zeros([], "float32")
+    astext(x)
+
 if __name__ == "__main__":
     do_print[0] = True
+    test_lstm()
+    test_zeros()
+    test_meta_data()
+    test_let_inlining()
     test_resnet()
     test_mobilenet()
     test_mlp()
@@ -207,9 +229,7 @@ if __name__ == "__main__":
     test_densenet()
     test_func()
     test_env()
-    test_meta_data()
     test_call_attrs()
     test_let_if_scope()
     test_variable_name()
     test_call_node_order()
-    test_let_inlining()