add an example gtest case, useful for unit-testing compiler pass

frontends/p4/p4-parse.h

@@ -1,5 +1,5 @@
 /*
-Copyright 2013-present Barefoot Networks, Inc. 
+Copyright 2013-present Barefoot Networks, Inc.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -23,5 +23,6 @@ limitations under the License.
 namespace IR { class Global; }
 
 const IR::P4Program *parse_P4_16_file(const char *name, FILE *in);
+const IR::P4Program *parse_string(const std::string &pgm);
 
 #endif /* _P4_P4_PARSE_H_ */

frontends/p4/p4-parse.ypp

@@ -60,7 +60,6 @@ static Util::ProgramStructure structure;
 
 namespace {  // anonymous namespace
 static int yylex();
-
 %}
 
 %union {
@@ -1034,6 +1033,19 @@ const IR::P4Program *parse_P4_16_file(const char *name, FILE *in) {
     return new IR::P4Program(declarations->srcInfo, declarations);
 }
 
+const IR::P4Program *parse_string(const std::string &pgm) {
+    int errors = 0;
+    declarations = new IR::IndexedVector<IR::Node>();
+    YY_BUFFER_STATE state = yy_scan_string(pgm.c_str());
+    errors |= yyparse();
+    yy_delete_buffer(state);
+    if (errors)
+        return nullptr;
+    structure.clear();
+    allErrors = nullptr;
+    return new IR::P4Program(declarations->srcInfo, declarations);
+}
+
 // check that right shift >>
 // has the two tokens at consecutive positions
 // (not separated by anything else)

frontends/p4/symbol_table.cpp

@@ -100,6 +100,9 @@ class Namespace : public NamedSymbol {
         into << s;
         into << "}" << std::endl;
     }
+    void clear() {
+        contents.clear();
+    }
 };
 
 class Object : public NamedSymbol {
@@ -238,4 +241,8 @@ cstring ProgramStructure::toString() const {
     rootNamespace->dump(res, 0);
     return cstring(res.str());
 }
+
+void ProgramStructure::clear() {
+    rootNamespace->clear();
+}
 }  // namespace Util

frontends/p4/symbol_table.h

@@ -78,6 +78,7 @@ class ProgramStructure final {
     void endParse();
 
     cstring toString() const;
+    void clear();
 };
 
 }  // namespace Util

test/gtest/Makefile.am

@@ -15,7 +15,8 @@
 # General GTest unit tests. Add tests here if they don't have a logical home
 # elsewhere in the codebase.
 gtest_unittest_UNIFIED = \
-	test/gtest/opeq_test.cpp
+	test/gtest/opeq_test.cpp \
+	test/gtest/typecheck_test.cpp
 
 cpplint_FILES += $(gtest_unittest_UNIFIED)
 gtest_SOURCES += $(gtest_unittest_SOURCES)

test/gtest/helper.h

@@ -0,0 +1,25 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include <string>
+
+/* preprocessing by prepending the content of core.p4 to test program */
+std::string with_core_p4 (const std::string& pgm) {
+    std::ifstream input("p4include/core.p4");
+    std::stringstream sstr;
+    while(input >> sstr.rdbuf());
+    return sstr.str() + pgm;
+}

test/gtest/typecheck_test.cpp

@@ -0,0 +1,77 @@
+/*
+Copyright 2013-present Barefoot Networks, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include "gtest/gtest.h"
+
+#include "ir/ir.h"
+#include "p4/p4-parse.h"
+#include "frontends/p4/typeMap.h"
+#include "frontends/common/constantFolding.h"
+#include "frontends/p4/typeChecking/bindVariables.h"
+#include "frontends/common/resolveReferences/resolveReferences.h"
+
+#include "p4/validateParsedProgram.h"
+#include "p4/createBuiltins.h"
+#include "p4/unusedDeclarations.h"
+#include "p4/typeChecking/typeChecker.h"
+
+#include "helper.h"
+
+using namespace P4;
+
+TEST(UNITTEST, helloworld) {
+    std::string program = with_core_p4(
+        "parser Parser<H, M> (packet_in p){ state start{} };\n"
+        "control empty() { apply {} };\n"
+        "package top(empty e);\n"
+        "top(empty()) main;\n");
+
+    const IR::P4Program* pgm = parse_string(program);
+    ASSERT_NE(nullptr, pgm);
+
+    ReferenceMap  refMap;
+    TypeMap       typeMap;
+
+    PassManager passes = {
+      new ValidateParsedProgram(false),
+      new CreateBuiltins(),
+      new ResolveReferences(&refMap, true),
+      new ConstantFolding(&refMap, nullptr),
+      new ResolveReferences(&refMap),
+//      new TypeInference(&refMap, &typeMap),
+    };
+
+    pgm = pgm->apply(passes);
+
+    ASSERT_NE(nullptr, pgm);
+}
+
+TEST(UNITTEST, package) {
+    std::string program = with_core_p4(
+        "parser Parser<H, M> (packet_in p){ state start{} };\n"
+        "control empty() { apply {} };\n"
+        "package top(empty e);\n");
+
+    const IR::P4Program* pgm = parse_string(program);
+
+    ASSERT_NE(nullptr, pgm);
+
+    PassManager passes = {
+        new CreateBuiltins(),
+    };
+    pgm = pgm->apply(passes);
+    dump(pgm);
+}