Parse mode tags in version scripts

header-abi-linker filters symbols tagged with llndk, apex, or systemapi
in version scripts. The filtering logic is copied from
build/soong/cc/symbolfile.

Usage:
- By default, header-abi-linker includes every symbol in the version
  script.
- `-api 34 -include-symbol-tag llndk=202404` includes LLNDK 202404 and
  NDK 34.
- `-api 35 -include-symbol-tag none` includes NDK 35, but excludes
  LLNDK and APEX.

Test: LD_LIBRARY_PATH=out/soong/dist/lib64 \
      out/soong/host/linux-x86/nativetest64/header-checker-unittests/header-checker-unittests
Bug: 314010764
Change-Id: I362995068af0ea6dff317078b8624be46e3b404a

4 files changed, 203 insertions, 29 deletions

diff --git a/vndk/tools/header-checker/src/linker/header_abi_linker.cpp b/vndk/tools/header-checker/src/linker/header_abi_linker.cpp
index 657504ecc..a12677796 100644
--- a/vndk/tools/header-checker/src/linker/header_abi_linker.cpp
+++ b/vndk/tools/header-checker/src/linker/header_abi_linker.cpp
@@ -81,9 +81,19 @@ static llvm::cl::list<std::string> excluded_symbol_tags(
     "exclude-symbol-tag", llvm::cl::Optional,
     llvm::cl::cat(header_linker_category));
 
+static llvm::cl::list<std::string> included_symbol_tags(
+    "include-symbol-tag",
+    llvm::cl::desc("Filter the symbols in the version script by mode tag, "
+                   "such as llndk, apex, and systemapi. The format is "
+                   "<tag>=<level> or <tag>. If this option is not specified, "
+                   "all mode tags are included."),
+    llvm::cl::Optional, llvm::cl::cat(header_linker_category));
+
 static llvm::cl::opt<std::string> api(
-    "api", llvm::cl::desc("<api>"), llvm::cl::Optional,
-    llvm::cl::init("current"),
+    "api",
+    llvm::cl::desc("Filter the symbols in the version script by comparing "
+                   "\"introduced\" tags and the specified API level."),
+    llvm::cl::Optional, llvm::cl::init("current"),
     llvm::cl::cat(header_linker_category));
 
 static llvm::cl::opt<std::string> api_map(
@@ -480,6 +490,12 @@ static bool InitializeVersionScriptParser(repr::VersionScriptParser &parser) {
   for (auto &&tag : excluded_symbol_tags) {
     parser.AddExcludedSymbolTag(tag);
   }
+  for (auto &&tag : included_symbol_tags) {
+    if (!parser.AddModeTag(tag)) {
+      llvm::errs() << "Failed to parse -include-symbol-tag " << tag << "\n";
+      return false;
+    }
+  }
 
   return true;
 }
diff --git a/vndk/tools/header-checker/src/repr/symbol/version_script_parser.cpp b/vndk/tools/header-checker/src/repr/symbol/version_script_parser.cpp
index fe1735587..931064b21 100644
--- a/vndk/tools/header-checker/src/repr/symbol/version_script_parser.cpp
+++ b/vndk/tools/header-checker/src/repr/symbol/version_script_parser.cpp
@@ -30,8 +30,14 @@ namespace header_checker {
 namespace repr {
 
 
-static constexpr char DEFAULT_ARCH[] = "arm64";
+using ModeTagLevel = std::pair<std::string_view, utils::ApiLevel>;
+
 
+static constexpr char DEFAULT_ARCH[] = "arm64";
+static constexpr utils::ApiLevel MIN_MODE_TAG_LEVEL = 0;
+static constexpr utils::ApiLevel MAX_MODE_TAG_LEVEL = 1000000;
+static const std::set<std::string_view> KNOWN_MODE_TAGS{"apex", "llndk",
+                                                        "systemapi"};
 
 inline std::string GetIntroducedArchTag(const std::string &arch) {
   return "introduced-" + arch + "=";
@@ -55,12 +61,39 @@ void VersionScriptParser::SetApiLevelMap(utils::ApiLevelMap api_level_map) {
 }
 
 
+static std::optional<ModeTagLevel> ParseModeTag(std::string_view tag,
+                                                utils::ApiLevel default_level) {
+  std::vector<std::string_view> split_tag = utils::Split(tag, "=");
+  utils::ApiLevel level = default_level;
+  if (split_tag.size() == 2) {
+    auto level = utils::ParseInt(std::string(split_tag[1]));
+    if (level.has_value()) {
+      return {{split_tag[0], level.value()}};
+    }
+  } else if (split_tag.size() == 1) {
+    return {{split_tag[0], default_level}};
+  }
+  return {};
+}
+
+
+bool VersionScriptParser::AddModeTag(std::string_view mode_tag) {
+  auto parsed_mode_tag = ParseModeTag(mode_tag, MAX_MODE_TAG_LEVEL);
+  if (parsed_mode_tag.has_value()) {
+    included_mode_tags_[std::string(parsed_mode_tag->first)] =
+        parsed_mode_tag->second;
+    return true;
+  }
+  return false;
+}
+
+
 VersionScriptParser::ParsedTags VersionScriptParser::ParseSymbolTags(
-    const std::string &line) {
+    const std::string &line, const ParsedTags &initial_value) {
   static const char *const POSSIBLE_ARCHES[] = {
       "arm", "arm64", "x86", "x86_64", "mips", "mips64"};
 
-  ParsedTags result;
+  ParsedTags result = initial_value;
 
   std::string_view line_view(line);
   std::string::size_type comment_pos = line_view.find('#');
@@ -138,36 +171,62 @@ VersionScriptParser::ParsedTags VersionScriptParser::ParseSymbolTags(
       result.has_weak_tag_ = true;
       continue;
     }
+
+    auto mode_tag = ParseModeTag(tag, MIN_MODE_TAG_LEVEL);
+    if (mode_tag.has_value() &&
+        (KNOWN_MODE_TAGS.count(mode_tag->first) > 0 ||
+         included_mode_tags_.count(mode_tag->first) > 0)) {
+      result.mode_tags_[std::string(mode_tag->first)] = mode_tag->second;
+    }
   }
 
   return result;
 }
 
 
-bool VersionScriptParser::IsSymbolExported(
-    const VersionScriptParser::ParsedTags &tags) {
-  if (tags.has_excluded_tags_) {
+bool VersionScriptParser::MatchModeTags(const ParsedTags &tags) {
+  for (const auto &mode_tag : tags.mode_tags_) {
+    auto included_mode_tag = included_mode_tags_.find(mode_tag.first);
+    if (included_mode_tag != included_mode_tags_.end() &&
+        included_mode_tag->second >= mode_tag.second) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
+bool VersionScriptParser::MatchIntroducedTags(const ParsedTags &tags) {
+  if (tags.has_future_tag_ && api_level_ < utils::FUTURE_API_LEVEL) {
+    return false;
+  }
+  if (tags.has_introduced_tags_ && api_level_ < tags.introduced_) {
     return false;
   }
+  return true;
+}
 
-  if (tags.has_arch_tags_ && !tags.has_current_arch_tag_) {
+
+bool VersionScriptParser::IsSymbolExported(const ParsedTags &tags) {
+  if (tags.has_excluded_tags_) {
     return false;
   }
 
-  if (tags.has_future_tag_) {
-    return api_level_ == utils::FUTURE_API_LEVEL;
+  if (tags.has_arch_tags_ && !tags.has_current_arch_tag_) {
+    return false;
   }
 
-  if (tags.has_introduced_tags_) {
-    return api_level_ >= tags.introduced_;
+  if (!included_mode_tags_.empty() && !tags.mode_tags_.empty()) {
+    return MatchModeTags(tags);
   }
 
-  return true;
+  return MatchIntroducedTags(tags);
 }
 
 
-bool VersionScriptParser::ParseSymbolLine(const std::string &line,
-                                          bool is_in_extern_cpp) {
+bool VersionScriptParser::ParseSymbolLine(
+    const std::string &line, bool is_in_extern_cpp,
+    const ParsedTags &version_block_tags) {
   // The symbol name comes before the ';'.
   std::string::size_type pos = line.find(";");
   if (pos == std::string::npos) {
@@ -177,7 +236,7 @@ bool VersionScriptParser::ParseSymbolLine(const std::string &line,
 
   std::string symbol(utils::Trim(line.substr(0, pos)));
 
-  ParsedTags tags = ParseSymbolTags(line);
+  ParsedTags tags = ParseSymbolTags(line, version_block_tags);
   if (!IsSymbolExported(tags)) {
     return true;
   }
@@ -209,7 +268,8 @@ bool VersionScriptParser::ParseSymbolLine(const std::string &line,
 }
 
 
-bool VersionScriptParser::ParseVersionBlock(bool ignore_symbols) {
+bool VersionScriptParser::ParseVersionBlock(bool ignore_symbols,
+                                            const ParsedTags &tags) {
   static const std::regex EXTERN_CPP_PATTERN(R"(extern\s*"[Cc]\+\+"\s*\{)");
 
   LineScope scope = LineScope::GLOBAL;
@@ -250,7 +310,7 @@ bool VersionScriptParser::ParseVersionBlock(bool ignore_symbols) {
 
     // Parse symbol line
     if (!ignore_symbols) {
-      if (!ParseSymbolLine(line, is_in_extern_cpp)) {
+      if (!ParseSymbolLine(line, is_in_extern_cpp, tags)) {
         return false;
       }
     }
@@ -285,8 +345,8 @@ std::unique_ptr<ExportedSymbolSet> VersionScriptParser::Parse(
     bool exclude_symbol_version = utils::HasMatchingGlobPattern(
         excluded_symbol_versions_, version.c_str());
 
-    ParsedTags tags = ParseSymbolTags(line);
-    if (!ParseVersionBlock(exclude_symbol_version || !IsSymbolExported(tags))) {
+    ParsedTags tags = ParseSymbolTags(line, ParsedTags());
+    if (!ParseVersionBlock(exclude_symbol_version, tags)) {
       return nullptr;
     }
   }
diff --git a/vndk/tools/header-checker/src/repr/symbol/version_script_parser.h b/vndk/tools/header-checker/src/repr/symbol/version_script_parser.h
index 74ca72f1a..0f468b55d 100644
--- a/vndk/tools/header-checker/src/repr/symbol/version_script_parser.h
+++ b/vndk/tools/header-checker/src/repr/symbol/version_script_parser.h
@@ -20,7 +20,7 @@
 #include "utils/api_level.h"
 
 #include <functional>
-#include <set>
+#include <map>
 #include <string>
 
 
@@ -30,12 +30,14 @@ namespace repr {
 
 class VersionScriptParser {
  private:
+  // This comparison function allows finding elements by string_view.
+  using ModeTagLevelMap = std::map<std::string, utils::ApiLevel, std::less<>>;
+
   enum class LineScope {
     GLOBAL,
     LOCAL,
   };
 
-
   struct ParsedTags {
    public:
     unsigned has_arch_tags_ : 1;
@@ -46,7 +48,7 @@ class VersionScriptParser {
     unsigned has_var_tag_ : 1;
     unsigned has_weak_tag_ : 1;
     utils::ApiLevel introduced_;
-
+    ModeTagLevelMap mode_tags_;
 
    public:
     ParsedTags()
@@ -84,6 +86,9 @@ class VersionScriptParser {
     excluded_symbol_tags_.insert(tag);
   }
 
+  // Returns whether the argument is valid.
+  bool AddModeTag(std::string_view mode_tag);
+
   void SetErrorHandler(std::unique_ptr<ErrorHandler> error_handler) {
     error_handler_ = std::move(error_handler);
   }
@@ -94,11 +99,17 @@ class VersionScriptParser {
  private:
   bool ReadLine(std::string &line);
 
-  bool ParseVersionBlock(bool ignore_symbols);
+  bool ParseVersionBlock(bool ignore_symbols, const ParsedTags &tags);
+
+  bool ParseSymbolLine(const std::string &line, bool is_cpp_symbol,
+                       const ParsedTags &version_block_tags);
+
+  ParsedTags ParseSymbolTags(const std::string &line,
+                             const ParsedTags &initial_value);
 
-  bool ParseSymbolLine(const std::string &line, bool is_cpp_symbol);
+  bool MatchModeTags(const ParsedTags &tags);
 
-  ParsedTags ParseSymbolTags(const std::string &line);
+  bool MatchIntroducedTags(const ParsedTags &tags);
 
   bool IsSymbolExported(const ParsedTags &tags);
 
@@ -121,6 +132,7 @@ class VersionScriptParser {
 
   utils::StringSet excluded_symbol_versions_;
   utils::StringSet excluded_symbol_tags_;
+  ModeTagLevelMap included_mode_tags_;
 
   std::istream *stream_;
   int line_no_;
diff --git a/vndk/tools/header-checker/src/repr/symbol/version_script_parser_test.cpp b/vndk/tools/header-checker/src/repr/symbol/version_script_parser_test.cpp
index 15e13517e..41955f3b0 100644
--- a/vndk/tools/header-checker/src/repr/symbol/version_script_parser_test.cpp
+++ b/vndk/tools/header-checker/src/repr/symbol/version_script_parser_test.cpp
@@ -174,8 +174,9 @@ TEST(VersionScriptParserTest, ParseSymbolTagsIntroduced) {
     ASSERT_TRUE(result);
 
     const ExportedSymbolSet::FunctionMap &funcs = result->GetFunctions();
-
-    EXPECT_TRUE(funcs.empty());
+    // This may be an undefined behavior. ndkstubgen includes it in llndk mode,
+    // but excludes it in ndk mode.
+    EXPECT_THAT(funcs, ElementsAre(Key("test5")));
   }
 
   {
@@ -355,6 +356,91 @@ TEST(VersionScriptParserTest, ExcludeSymbolTags) {
 }
 
 
+TEST(VersionScriptParserTest, IncludeSymbolTags) {
+  static const char testdata[] = R"TESTDATA(
+    LIBEX_1.0 {
+      global:
+        always;  # unknown
+        api34;  # introduced=34
+        api35;  # introduced=35
+        api35_llndk202404;  # introduced=35 llndk=202404
+        systemapi;  # systemapi
+        systemapi_llndk;  # systemapi llndk
+    };
+    LIBEX_2.0 {  # introduced=36
+        api36_llndk202504;
+        api36_llndk202504;  # llndk=202504
+    };
+  )TESTDATA";
+
+  {
+    VersionScriptParser parser;
+    parser.SetApiLevel(34);
+    parser.AddModeTag("llndk=202404");
+
+    std::istringstream stream(testdata);
+    std::unique_ptr<ExportedSymbolSet> result(parser.Parse(stream));
+    ASSERT_TRUE(result);
+
+    const ExportedSymbolSet::FunctionMap &funcs = result->GetFunctions();
+
+    EXPECT_THAT(funcs,
+                ElementsAre(Key("always"), Key("api34"),
+                            Key("api35_llndk202404"), Key("systemapi_llndk")));
+  }
+
+  {
+    VersionScriptParser parser;
+    parser.SetApiLevel(34);
+    parser.AddModeTag("llndk");
+
+    std::istringstream stream(testdata);
+    std::unique_ptr<ExportedSymbolSet> result(parser.Parse(stream));
+    ASSERT_TRUE(result);
+
+    const ExportedSymbolSet::FunctionMap &funcs = result->GetFunctions();
+
+    EXPECT_THAT(
+        funcs,
+        ElementsAre(Key("always"), Key("api34"), Key("api35_llndk202404"),
+                    Key("api36_llndk202504"), Key("systemapi_llndk")));
+  }
+
+  // Include all mode tags
+  {
+    VersionScriptParser parser;
+    parser.SetApiLevel(utils::FUTURE_API_LEVEL);
+
+    std::istringstream stream(testdata);
+    std::unique_ptr<ExportedSymbolSet> result(parser.Parse(stream));
+    ASSERT_TRUE(result);
+
+    const ExportedSymbolSet::FunctionMap &funcs = result->GetFunctions();
+
+    EXPECT_THAT(funcs,
+                ElementsAre(Key("always"), Key("api34"), Key("api35"),
+                            Key("api35_llndk202404"), Key("api36_llndk202504"),
+                            Key("systemapi"), Key("systemapi_llndk")));
+  }
+
+  // Exclude all mode tags
+  {
+    VersionScriptParser parser;
+    parser.SetApiLevel(utils::FUTURE_API_LEVEL);
+    parser.AddModeTag("none");
+
+    std::istringstream stream(testdata);
+    std::unique_ptr<ExportedSymbolSet> result(parser.Parse(stream));
+    ASSERT_TRUE(result);
+
+    const ExportedSymbolSet::FunctionMap &funcs = result->GetFunctions();
+
+    EXPECT_THAT(funcs, ElementsAre(Key("always"), Key("api34"), Key("api35"),
+                                   Key("api36_llndk202504")));
+  }
+}
+
+
 TEST(VersionScriptParserTest, ParseExternCpp) {
   static const char testdata[] = R"TESTDATA(
     LIBEX_1.0 {