[Relay] Roundtrip part of pretty printer and parser (apache#3460)

* init

fix rebase

lint

fix cmake

try again

fix ci

* add gitignore

* fix format

* do not include .interp and .tokens

.gitignore

@@ -217,13 +217,18 @@ patched.txt
 .mypy_cache/
 .pyre/
 
-# pipenv file
+# pipenv files
 Pipfile
 Pipfile.lock
 
 # conda package artifacts
 conda/Dockerfile.cuda*
 conda/pkg
 
+# nix files
 .envrc
-*.nix
+*.nix
+
+# antlr files
+*.tokens
+*.interp

cmake/modules/ANTLR.cmake

@@ -14,21 +14,49 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-
 if(USE_ANTLR)
-  set(RELAY_PARSER_DIR
-    ${CMAKE_CURRENT_SOURCE_DIR}/python/tvm/relay/grammar)
+  find_program(ANTLR4 antlr4)
+
+  if (NOT ANTLR4)
+    file(GLOB_RECURSE ANTLR4JAR
+          /usr/local/lib/antlr-*-complete.jar
+          /usr/local/Cellar/*antlr-*-complete.jar)
+
+    # Get the first element of the list of antlr jars.
+    # Sort and reverse the list so the item selected is the highest
+    #   version in lib or else in Cellar if no lib installation exists.
+    list(SORT ANTLR4JAR)
+    list(REVERSE ANTLR4JAR)
+    list(GET ANTLR4JAR 0 ANTLR4JAR)
+
+    set(JAVA_HOME $ENV{JAVA_HOME})
+    if (NOT DEFINED JAVA_HOME)
+      # Hack to get system to search for Java itself.
+      set(JAVA_HOME "/usr")
+    endif()
+
+    set(ANTLR4 ${JAVA_HOME}/bin/java -jar ${ANTLR4JAR})
+  endif()
+
+  if(ANTLR4)
+
+    set(RELAY_PARSER_DIR
+      ${CMAKE_CURRENT_SOURCE_DIR}/python/tvm/relay/grammar)
+
+    set(RELAY_PARSER
+      ${RELAY_PARSER_DIR}/py3/RelayVisitor.py
+      ${RELAY_PARSER_DIR}/py3/RelayParser.py
+      ${RELAY_PARSER_DIR}/py3/RelayLexer.py)
 
-  set(RELAY_PARSER
-    ${RELAY_PARSER_DIR}/py3/RelayVisitor.py
-    ${RELAY_PARSER_DIR}/py3/RelayParser.py
-    ${RELAY_PARSER_DIR}/py3/RelayLexer.py)
 
-  # Generate ANTLR grammar for parsing.
-  add_custom_command(OUTPUT ${RELAY_PARSER}
-    COMMAND antlr4 -visitor -no-listener -Dlanguage=Python3 ${RELAY_PARSER_DIR}/Relay.g4 -o ${RELAY_PARSER_DIR}/py3
-    DEPENDS ${RELAY_PARSER_DIR}/Relay.g4
-    WORKING_DIRECTORY ${RELAY_PARSER_DIR})
+    # Generate ANTLR grammar for parsing.
+    add_custom_command(OUTPUT ${RELAY_PARSER}
+      COMMAND ${ANTLR4} -visitor -no-listener -Dlanguage=Python3 ${RELAY_PARSER_DIR}/Relay.g4 -o ${RELAY_PARSER_DIR}/py3
+      DEPENDS ${RELAY_PARSER_DIR}/Relay.g4
+      WORKING_DIRECTORY ${RELAY_PARSER_DIR})
 
-  add_custom_target(relay_parser ALL DEPENDS ${RELAY_PARSER})
+    add_custom_target(relay_parser ALL DEPENDS ${RELAY_PARSER})
+  else()
+    message(FATAL_ERROR "Can't find ANTLR4")
+  endif()
 endif(USE_ANTLR)

python/tvm/relay/_parser.py

@@ -206,7 +206,7 @@ def visitTerminal(self, node):
         if node_type == RelayLexer.NAT:
             return int(node_text)
         if node_type == RelayLexer.FLOAT:
-            return float(node_text)
+            return float(node_text[:-1])
         if node_type == RelayLexer.BOOL_LIT:
             if node_text == "True":
                 return True
@@ -375,6 +375,8 @@ def mk_func(self, ctx):
                 self.mk_typ(name, ty.Kind.Type)
 
         var_list, attr_list = self.visit(ctx.argList())
+        if var_list is None:
+            var_list = []
         ret_type = self.getType_(ctx.type_())
 
         body = self.visit(ctx.body())
@@ -387,7 +389,6 @@ def mk_func(self, ctx):
         self.exit_var_scope()
 
         attrs = tvm.make.node("DictAttrs", **attr_list) if attr_list is not None else None
-
         return expr.Function(var_list, body, ret_type, type_params, attrs)
 
     @spanify

python/tvm/relay/grammar/Relay.g4

@@ -19,7 +19,7 @@
 
 grammar Relay;
 
-SEMVER: 'v0.0.2' ;
+SEMVER: 'v0.0.3' ;
 
 // Lexing
 // comments
@@ -52,10 +52,9 @@ BOOL_LIT
   ;
 
 // non-negative floats
-FLOAT
-  : NAT '.' NAT EXP? // 1.35, 1.35E-9, 0.3, 4.5
-  | NAT EXP // 1e10 3e4
-  ;
+fragment PREFLOAT : NAT ('.' NAT)? EXP?; // 1.35, 1.35E-9, 0.3, 4.5, 1, 1e10 3e4
+
+FLOAT : PREFLOAT 'f';
 
 // non-negative ints
 NAT: DIGIT+ ;

python/tvm/relay/grammar/py3/.gitattributes

@@ -0,0 +1,3 @@
+Relay* binary
+Relay* linguist-generated=true
+Relay* linguist-detectable=false