[clang] [WebAssembly] Add error checking for -wasm-use-legacy-ch (PR #122526)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Heejin Ahn (aheejin)

<details>
<summary>Changes</summary>

This adds checks for `-wasm-use-legacy-eh`. While this option is true by default in the backend, it is not supposed to be given to the Clang when Wasm EH is not used.

---
Full diff: https://github.com/llvm/llvm-project/pull/122526.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/WebAssembly.cpp (+2-1) 
- (modified) clang/test/Driver/wasm-toolchain.c (+22) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp
index e338b0d2398e04..10f9a4f338f8f1 100644
--- a/clang/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -422,7 +422,8 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
       }
     }
 
-    for (const auto *Option : {"-wasm-enable-eh", "-wasm-enable-sjlj"}) {
+    for (const auto *Option :
+         {"-wasm-enable-eh", "-wasm-enable-sjlj", "-wasm-use-legacy-eh"}) {
       if (Opt.starts_with(Option)) {
         BanIncompatibleOptionsForWasmEHSjLj(Option);
         EnableFeaturesForWasmEHSjLj();
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
index 84c1b4f6efe662..2d140520827768 100644
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/test/Driver/wasm-toolchain.c
@@ -202,6 +202,28 @@
 // RUN:   | FileCheck -check-prefix=WASM_SJLJ_NO_REFERENCE_TYPES %s
 // WASM_SJLJ_NO_REFERENCE_TYPES: invalid argument '-wasm-enable-sjlj' not allowed with '-mno-reference-types'
 
+// '-mllvm -wasm-use-legacy-eh' not allowed with
+// '-mllvm -enable-emscripten-cxx-exceptions'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -mllvm -wasm-use-legacy-eh \
+// RUN:     -mllvm -enable-emscripten-cxx-exceptions 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_LEGACY_EH_EMSCRIPTEN_EH %s
+// WASM_LEGACY_EH_EMSCRIPTEN_EH: invalid argument '-wasm-use-legacy-eh' not allowed with '-enable-emscripten-cxx-exceptions'
+
+// '-mllvm -wasm-use-legacy-eh' not allowed with '-mllvm -enable-emscripten-sjlj'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -mllvm -wasm-use-legacy-eh \
+// RUN:     -mllvm -enable-emscripten-sjlj 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_LEGACY_EH_EMSCRIPTEN_SJLJ %s
+// WASM_LEGACY_EH_EMSCRIPTEN_SJLJ: invalid argument '-wasm-use-legacy-eh' not allowed with '-enable-emscripten-sjlj'
+
+// '-mllvm -wasm-use-legacy-eh' not allowed with '-mno-exception-handling'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -mllvm -wasm-use-legacy-eh \
+// RUN:     -mno-exception-handling 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_LEGACY_EH_NO_EH %s
+// WASM_LEGACY_EH_NO_EH: invalid argument '-wasm-use-legacy-eh' not allowed with '-mno-exception-handling'
+
 // RUN: %clang -### %s -fsanitize=address --target=wasm32-unknown-emscripten 2>&1 | FileCheck -check-prefix=CHECK-ASAN-EMSCRIPTEN %s
 // CHECK-ASAN-EMSCRIPTEN: "-fsanitize=address"
 // CHECK-ASAN-EMSCRIPTEN: "-fsanitize-address-globals-dead-stripping"

``````````

</details>


https://github.com/llvm/llvm-project/pull/122526