[clang] [clang-repl] Handle frontend options for clang-repl before calling executeAction (PR #132670)

[Anutosh Bhat via cfe-commits]

https://github.com/anutosh491 updated https://github.com/llvm/llvm-project/pull/132670

>From 6545414a97b6458333f399c7252ae55c88a42d62 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Mon, 24 Mar 2025 10:09:59 +0530
Subject: [PATCH 1/3] Handle frontend options for clang-repl before calling
 executeAction

---
 clang/lib/Interpreter/Interpreter.cpp | 38 ++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index fa4c1439c9261..5f48117dbf3b8 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -141,6 +141,37 @@ CreateCI(const llvm::opt::ArgStringList &Argv) {
   return std::move(Clang);
 }
 
+static llvm::Error HandleFrontendOptions(const CompilerInstance &CI) {
+  const auto &FrontendOpts = CI.getFrontendOpts();
+
+  if (FrontendOpts.ShowHelp) {
+    driver::getDriverOptTable().printHelp(
+        llvm::outs(), "clang -cc1 [options] file...",
+        "LLVM 'Clang' Compiler: http://clang.llvm.org",
+        /*ShowHidden=*/false, /*ShowAllAliases=*/false,
+        llvm::opt::Visibility(driver::options::CC1Option));
+    return llvm::createStringError(llvm::errc::not_supported, "Help displayed");
+  }
+
+  if (FrontendOpts.ShowVersion) {
+    llvm::cl::PrintVersionMessage();
+    return llvm::createStringError(llvm::errc::not_supported, "Version displayed");
+  }
+
+  if (!FrontendOpts.LLVMArgs.empty()) {
+    unsigned NumArgs = FrontendOpts.LLVMArgs.size();
+    auto Args = std::make_unique<const char*[]>(NumArgs + 2);
+    Args[0] = "clang-repl (LLVM option parsing)";
+    for (unsigned i = 0; i != NumArgs; ++i)
+      Args[i + 1] = FrontendOpts.LLVMArgs[i].c_str();
+    Args[NumArgs + 1] = nullptr;
+    llvm::errs() << "Parsing LLVM backend options via cl::ParseCommandLineOptions...\n";
+    llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
+  }
+
+  return llvm::Error::success();
+}
+
 } // anonymous namespace
 
 namespace clang {
@@ -451,7 +482,12 @@ const char *const Runtimes = R"(
 
 llvm::Expected<std::unique_ptr<Interpreter>>
 Interpreter::create(std::unique_ptr<CompilerInstance> CI) {
-  llvm::Error Err = llvm::Error::success();
+
+  llvm::Error Err = HandleFrontendOptions(*CI);
+  if (Err) {
+    return std::move(Err);
+  }
+
   auto Interp =
       std::unique_ptr<Interpreter>(new Interpreter(std::move(CI), Err));
   if (Err)

>From fa4e295389e51da41b6b96baed099e739664b730 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Mon, 24 Mar 2025 10:29:03 +0530
Subject: [PATCH 2/3] apply code formatting changes

---
 clang/lib/Interpreter/Interpreter.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index 5f48117dbf3b8..3fbfd3c746bc7 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -155,17 +155,19 @@ static llvm::Error HandleFrontendOptions(const CompilerInstance &CI) {
 
   if (FrontendOpts.ShowVersion) {
     llvm::cl::PrintVersionMessage();
-    return llvm::createStringError(llvm::errc::not_supported, "Version displayed");
+    return llvm::createStringError(llvm::errc::not_supported,
+                                   "Version displayed");
   }
 
   if (!FrontendOpts.LLVMArgs.empty()) {
     unsigned NumArgs = FrontendOpts.LLVMArgs.size();
-    auto Args = std::make_unique<const char*[]>(NumArgs + 2);
+    auto Args = std::make_unique<const char *[]>(NumArgs + 2);
     Args[0] = "clang-repl (LLVM option parsing)";
     for (unsigned i = 0; i != NumArgs; ++i)
       Args[i + 1] = FrontendOpts.LLVMArgs[i].c_str();
     Args[NumArgs + 1] = nullptr;
-    llvm::errs() << "Parsing LLVM backend options via cl::ParseCommandLineOptions...\n";
+    llvm::errs()
+        << "Parsing LLVM backend options via cl::ParseCommandLineOptions...\n";
     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
   }
 

>From 6219d14843e1324b8eaf09c12ff6d4ee88104e8d Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Thu, 10 Apr 2025 16:09:01 +0530
Subject: [PATCH 3/3] Add tests for native cases

---
 clang/lib/Interpreter/Interpreter.cpp         | 15 ++++++++++++---
 clang/test/Interpreter/handlefrontendopts.cpp |  5 +++++
 2 files changed, 17 insertions(+), 3 deletions(-)
 create mode 100644 clang/test/Interpreter/handlefrontendopts.cpp

diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index 3fbfd3c746bc7..15d3b033c1eee 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -163,11 +163,20 @@ static llvm::Error HandleFrontendOptions(const CompilerInstance &CI) {
     unsigned NumArgs = FrontendOpts.LLVMArgs.size();
     auto Args = std::make_unique<const char *[]>(NumArgs + 2);
     Args[0] = "clang-repl (LLVM option parsing)";
-    for (unsigned i = 0; i != NumArgs; ++i)
+    for (unsigned i = 0; i != NumArgs; ++i) {
       Args[i + 1] = FrontendOpts.LLVMArgs[i].c_str();
+      // remove the leading '-' from the option name
+      if (Args[i + 1][0] == '-') {
+        auto *option = static_cast<llvm::cl::opt<bool> *>(
+            llvm::cl::getRegisteredOptions()[Args[i + 1] + 1]);
+        if (option) {
+          option->setInitialValue(true);
+        } else {
+          llvm::errs() << "Unknown LLVM option: " << Args[i + 1] << "\n";
+        }
+      }
+    }
     Args[NumArgs + 1] = nullptr;
-    llvm::errs()
-        << "Parsing LLVM backend options via cl::ParseCommandLineOptions...\n";
     llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
   }
 
diff --git a/clang/test/Interpreter/handlefrontendopts.cpp b/clang/test/Interpreter/handlefrontendopts.cpp
new file mode 100644
index 0000000000000..7596a6e745a03
--- /dev/null
+++ b/clang/test/Interpreter/handlefrontendopts.cpp
@@ -0,0 +1,5 @@
+// RUN: not clang-repl --Xcc -Xclang --Xcc -help 2>&1 | FileCheck %s --check-prefix=HELP
+// RUN: not clang-repl --Xcc -Xclang --Xcc -version 2>&1 | FileCheck %s --check-prefix=VERSION
+
+// HELP: Help displayed
+// VERSION: Version displayed
\ No newline at end of file