From 2cad9a0f22c3203f1d1dd9d35613558bf443f4a4 Mon Sep 17 00:00:00 2001
From: David Fang <fangism@google.com>
Date: Mon, 30 Mar 2020 14:05:17 -0700
Subject: [PATCH] Allow identifier-like symbols for the import alias name.

Fixes crash in verilog::MakeDPIImport() with signature like:
  Check failed: E(leaf.get().token_enum) == expected_token_enum (293 vs. 292)

PiperOrigin-RevId: 303818326
---
 verilog/CST/BUILD                         |  2 ++
 verilog/CST/DPI.h                         | 25 ++++++++++++++++++++++-
 verilog/parser/verilog_parser_unittest.cc | 10 +++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/verilog/CST/BUILD b/verilog/CST/BUILD
index d9ac37055..537f34529 100644
--- a/verilog/CST/BUILD
+++ b/verilog/CST/BUILD
@@ -152,9 +152,11 @@ cc_library(
         ":verilog_nonterminals",
         ":verilog_treebuilder_utils",
         "//common/analysis:syntax_tree_search",
+        "//common/text:concrete_syntax_leaf",
         "//common/text:concrete_syntax_tree",
         "//common/text:symbol",
         "//common/text:tree_utils",
+        "//verilog/parser:verilog_token_classifications",
         "//verilog/parser:verilog_token_enum",
     ],
 )
diff --git a/verilog/CST/DPI.h b/verilog/CST/DPI.h
index 3dc3e2314..7ecdbc780 100644
--- a/verilog/CST/DPI.h
+++ b/verilog/CST/DPI.h
@@ -23,11 +23,13 @@
 #include <vector>
 
 #include "common/analysis/syntax_tree_search.h"
+#include "common/text/concrete_syntax_leaf.h"
 #include "common/text/concrete_syntax_tree.h"
 #include "common/text/symbol.h"
 #include "common/text/tree_utils.h"
 #include "verilog/CST/verilog_nonterminals.h"
 #include "verilog/CST/verilog_treebuilder_utils.h"
+#include "verilog/parser/verilog_token_classifications.h"
 #include "verilog/parser/verilog_token_enum.h"
 
 namespace verilog {
@@ -38,7 +40,10 @@ verible::SymbolPtr MakeDPIImport(T0&& keyword, T1&& spec, T2&& property,
                                  T3&& id, T4&& equals, T5&& proto, T6&& semi) {
   verible::CheckSymbolAsLeaf(*keyword, verilog_tokentype::TK_import);
   verible::CheckSymbolAsLeaf(*spec, verilog_tokentype::TK_StringLiteral);
-  verible::CheckOptionalSymbolAsLeaf(id, verilog_tokentype::SymbolIdentifier);
+  if (id != nullptr) {
+    CHECK(IsIdentifierLike(
+        verilog_tokentype(verible::SymbolCastToLeaf(*id).get().token_enum)));
+  }
   verible::CheckOptionalSymbolAsLeaf(equals, '=');
   CHECK(verible::SymbolCastToNode(*proto).MatchesTagAnyOf(
       {NodeEnum::kFunctionPrototype, NodeEnum::kTaskPrototype}));
@@ -50,6 +55,24 @@ verible::SymbolPtr MakeDPIImport(T0&& keyword, T1&& spec, T2&& property,
       verible::ExtendNode(std::forward<T5>(proto), std::forward<T6>(semi)));
 }
 
+// Partial specialization provided as a workaround to passing nullptr
+// in positions 3 and 4 (optional symbols).  Compiler is not guaranteed
+// to deduce to that some paths are not reachble/applicable.
+template <typename T0, typename T1, typename T2, typename T3, typename T4>
+verible::SymbolPtr MakeDPIImport(T0&& keyword, T1&& spec, T2&& property,
+                                 nullptr_t id, nullptr_t equals, T3&& proto,
+                                 T4&& semi) {
+  verible::CheckSymbolAsLeaf(*keyword, verilog_tokentype::TK_import);
+  verible::CheckSymbolAsLeaf(*spec, verilog_tokentype::TK_StringLiteral);
+  CHECK(verible::SymbolCastToNode(*proto).MatchesTagAnyOf(
+      {NodeEnum::kFunctionPrototype, NodeEnum::kTaskPrototype}));
+  ExpectString(semi, ";");
+  return verible::MakeTaggedNode(
+      NodeEnum::kDPIImportItem, std::forward<T0>(keyword),
+      std::forward<T1>(spec), std::forward<T2>(property), id, equals,
+      verible::ExtendNode(std::forward<T3>(proto), std::forward<T4>(semi)));
+}
+
 // Find all DPI imports.
 std::vector<verible::TreeSearchMatch> FindAllDPIImports(const verible::Symbol&);
 
diff --git a/verilog/parser/verilog_parser_unittest.cc b/verilog/parser/verilog_parser_unittest.cc
index e7cd40a65..ab380edb5 100644
--- a/verilog/parser/verilog_parser_unittest.cc
+++ b/verilog/parser/verilog_parser_unittest.cc
@@ -2627,6 +2627,16 @@ static const char* kModuleTests[] = {
     "import pkg::ident;\n"
     "export \"name\" task rabbit;\n"
     "endmodule",
+    "import \"DPI\" function bar;\n",
+    "import \"DPI-C\" function bar;\n",
+    "import \"DPI-C\" foo = function bar;\n",
+    "import \"DPI-C\" foo = function void bar;\n",
+    "import \"DPI-C\" foo = function void bar();\n",
+    "import \"DPI-C\" foo = function void bar(input chandle ch);\n",
+    // using escaped identifier as alias:
+    "import \"DPI-C\" \\foo = function void bar(input chandle ch);\n",
+    "import \"DPI-C\" `foo = function void bar(input chandle ch);\n",  // macro
+    "import \"DPI-C\" foo = function longint unsigned bar(input chandle ch);\n",
     "module zoobar ();\n"
     "import \"DPI-C\" function void fizzbuzz (\n"
     "  input in val, output int nothing);\n"