feat(relinker): support explicit CLI help

core/relinker/CMakeLists.txt

@@ -198,6 +198,8 @@ if(BUILD_TESTING)
 
     find_package(Python3 QUIET COMPONENTS Interpreter)
     if(Python3_Interpreter_FOUND)
+        add_test(NAME cli_help COMMAND ${Python3_EXECUTABLE}
+            ${CMAKE_CURRENT_SOURCE_DIR}/cli/tests/test_help.py $<TARGET_FILE:relinker>)
         add_test(NAME elf_offsets COMMAND ${Python3_EXECUTABLE}
             ${CMAKE_CURRENT_SOURCE_DIR}/relinker/tests/test_elf_offsets.py $<TARGET_FILE:relinker>)
         add_test(NAME dynamic_segment COMMAND ${Python3_EXECUTABLE}

core/relinker/cli/include/Cli.hpp

@@ -8,6 +8,7 @@
 namespace Cli {
 
 struct Args {
+    bool showHelp = false;
     bool skipSyscallCheck = false;
     bool skipSceModule = false;
     bool toIntel = false;
@@ -27,6 +28,8 @@ struct Args {
 
 Args ParseArgs(int argc, char* argv[]);
 
+const char* Usage();
+
 int Autorun(const std::string& absPath, bool toWindows);
 
 }

core/relinker/cli/src/CliArgs.cpp

@@ -5,13 +5,20 @@
 
 namespace Cli {
 
+const char* Usage() {
+    return "Usage: relinker [--help] [--windows | --macos] [--windows-diagnostics] [--windows-gui] [--skip-syscall-check] [--skip-sce-module] [--exclude-sce-module <file>]... [--to-intel] [unused-filter=0|1|2] [--registry] [--rpath <path>] [--lazy-binding] [--autorun] <input.elf> <output.elf>\n"
+           "Example: relinker input.elf output.elf";
+}
+
 Args ParseArgs(int argc, char* argv[]) {
     Args args;
     bool unusedFilterSpecified = false;
 
     for (int i = 1; i < argc; ++i) {
         const std::string arg = argv[i];
-        if (arg == "--skip-syscall-check") {
+        if (arg == "--help") {
+            args.showHelp = true;
+        } else if (arg == "--skip-syscall-check") {
             args.skipSyscallCheck = true;
         } else if (arg == "--skip-sce-module") {
             args.skipSceModule = true;
@@ -67,11 +74,9 @@ Args ParseArgs(int argc, char* argv[]) {
     if (args.windowsGui && !args.toWindows)
         throw std::runtime_error("--windows-gui requires --windows");
 
-    if (args.inputPath.empty() || args.outputPath.empty())
-        throw std::runtime_error(
-            "Usage: relinker [--windows | --macos] [--windows-diagnostics] [--windows-gui] [--skip-syscall-check] [--skip-sce-module] [--exclude-sce-module <file>]... [--to-intel] [unused-filter=0|1|2] [--registry] [--rpath <path>] [--lazy-binding] [--autorun] <input.elf> <output.elf>\n"
-            "Example: relinker input.elf output.elf"
-        );
+    if (!args.showHelp && (args.inputPath.empty() || args.outputPath.empty()))
+        throw std::runtime_error(Usage());
+
 
     return args;
 }

core/relinker/cli/tests/test_help.py

@@ -0,0 +1,44 @@
+from pathlib import Path
+import subprocess
+import sys
+import tempfile
+
+
+def main():
+    relinker = Path(sys.argv[1]).resolve()
+    with tempfile.TemporaryDirectory(prefix="anyps5-help-") as directory:
+        work = Path(directory)
+        source = work / "missing.elf"
+        output = work / "existing.exe"
+        output.write_bytes(b"preserve this output")
+
+        def run(*args):
+            return subprocess.run([str(relinker), *args], cwd=work,
+                                  capture_output=True, text=True, timeout=10)
+
+        for args in [("--help",), ("--help", "--registry", "--autorun", str(source), str(output)),
+                     (str(source), str(output), "--help")]:
+            result = run(*args)
+            assert result.returncode == 0, result.stderr
+            assert result.stdout.startswith("Usage: relinker "), result.stdout
+            assert "--help" in result.stdout and "Example:" in result.stdout
+            assert result.stderr == "", result.stderr
+            assert output.read_bytes() == b"preserve this output"
+            assert sorted(path.name for path in work.iterdir()) == [output.name]
+
+        result = run()
+        assert result.returncode == 1 and "Usage: relinker" in result.stderr
+        for args in [("--help", "--unknown"), ("--unknown", "--help")]:
+            result = run(*args)
+            assert result.returncode == 1 and "unknown option" in result.stderr
+        result = run("--help", "--windows-gui")
+        assert result.returncode == 1 and "requires --windows" in result.stderr
+        for flag in ["--rpath", "--exclude-sce-module"]:
+            result = run(flag, "--help", str(source), str(output))
+            assert result.returncode == 2 and "Cannot open file" in result.stderr
+            assert result.stdout == "", result.stdout
+        assert output.read_bytes() == b"preserve this output"
+
+
+if __name__ == "__main__":
+    main()

core/relinker/main.cpp

@@ -37,6 +37,11 @@ int main(const int argc, char* argv[]) {
         return 1;
     }
 
+    if (args.showHelp) {
+        std::cout << Cli::Usage() << '\n';
+        return 0;
+    }
+
     try {
         auto extension = std::filesystem::path(args.outputPath).extension().string();
         for (auto& character : extension) if (character >= 'A' && character <= 'Z') character = static_cast<char>(character + ('a' - 'A'));