[WebAssembly] Make EH depend on multivalue and reference-types (#91299)

This PR turns on multivalue and reference-types features when
exception-handling feature is turned on, and errors out when disabling
of those dependent features is explicitly requested.

I think doing this would be safe anyway regardless of whether or when we
end up turning on reference-types by default.

We currently don't yet have a experimental flag for the Clang and LLVM
for the new experimental EH yet. But I think it should be fine to turn
those features on even if the LLVM does not yet generate the new EH
instructions, for the same reason we tried to turn them on by default
and the browsers that support EH also support multivalue and
reference-types anyway.

2 files changed, 67 insertions, 6 deletions

diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp
index b7c6efa..5b763df 100644
--- a/clang/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -347,6 +347,23 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
     // Backend needs -wasm-enable-eh to enable Wasm EH
     CC1Args.push_back("-mllvm");
     CC1Args.push_back("-wasm-enable-eh");
+
+    // New Wasm EH spec (adopted in Oct 2023) requires multivalue and
+    // reference-types.
+    if (DriverArgs.hasFlag(options::OPT_mno_multivalue,
+                           options::OPT_mmultivalue, false)) {
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-fwasm-exceptions" << "-mno-multivalue";
+    }
+    if (DriverArgs.hasFlag(options::OPT_mno_reference_types,
+                           options::OPT_mreference_types, false)) {
+      getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+          << "-fwasm-exceptions" << "-mno-reference-types";
+    }
+    CC1Args.push_back("-target-feature");
+    CC1Args.push_back("+multivalue");
+    CC1Args.push_back("-target-feature");
+    CC1Args.push_back("+reference-types");
   }
 
   for (const Arg *A : DriverArgs.filtered(options::OPT_mllvm)) {
@@ -408,6 +425,23 @@ void WebAssembly::addClangTargetOptions(const ArgList &DriverArgs,
       CC1Args.push_back("+exception-handling");
       // Backend needs '-exception-model=wasm' to use Wasm EH instructions
       CC1Args.push_back("-exception-model=wasm");
+
+      // New Wasm EH spec (adopted in Oct 2023) requires multivalue and
+      // reference-types.
+      if (DriverArgs.hasFlag(options::OPT_mno_multivalue,
+                             options::OPT_mmultivalue, false)) {
+        getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+            << "-mllvm -wasm-enable-sjlj" << "-mno-multivalue";
+      }
+      if (DriverArgs.hasFlag(options::OPT_mno_reference_types,
+                             options::OPT_mreference_types, false)) {
+        getDriver().Diag(diag::err_drv_argument_not_allowed_with)
+            << "-mllvm -wasm-enable-sjlj" << "-mno-reference-types";
+      }
+      CC1Args.push_back("-target-feature");
+      CC1Args.push_back("+multivalue");
+      CC1Args.push_back("-target-feature");
+      CC1Args.push_back("+reference-types");
     }
   }
 }
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
index dabf0ac..7c26c2c 100644
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/test/Driver/wasm-toolchain.c
@@ -120,11 +120,12 @@
 // RUN:   | FileCheck -check-prefix=EMSCRIPTEN_EH_ALLOWED_WO_ENABLE %s
 // EMSCRIPTEN_EH_ALLOWED_WO_ENABLE: invalid argument '-mllvm -emscripten-cxx-exceptions-allowed' only allowed with '-mllvm -enable-emscripten-cxx-exceptions'
 
-// '-fwasm-exceptions' sets +exception-handling and '-mllvm -wasm-enable-eh'
+// '-fwasm-exceptions' sets +exception-handling, -multivalue, -reference-types
+// and '-mllvm -wasm-enable-eh'
 // RUN: %clang -### --target=wasm32-unknown-unknown \
 // RUN:    --sysroot=/foo %s -fwasm-exceptions 2>&1 \
 // RUN:  | FileCheck -check-prefix=WASM_EXCEPTIONS %s
-// WASM_EXCEPTIONS: "-cc1" {{.*}} "-target-feature" "+exception-handling" "-mllvm" "-wasm-enable-eh"
+// WASM_EXCEPTIONS: "-cc1" {{.*}} "-target-feature" "+exception-handling" "-mllvm" "-wasm-enable-eh" "-target-feature" "+multivalue" "-target-feature" "+reference-types"
 
 // '-fwasm-exceptions' not allowed with '-mno-exception-handling'
 // RUN: not %clang -### --target=wasm32-unknown-unknown \
@@ -132,19 +133,32 @@
 // RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_NO_EH %s
 // WASM_EXCEPTIONS_NO_EH: invalid argument '-fwasm-exceptions' not allowed with '-mno-exception-handling'
 
-// '-fwasm-exceptions' not allowed with '-mllvm -enable-emscripten-cxx-exceptions'
+// '-fwasm-exceptions' not allowed with
+// '-mllvm -enable-emscripten-cxx-exceptions'
 // RUN: not %clang -### --target=wasm32-unknown-unknown \
 // RUN:     --sysroot=/foo %s -fwasm-exceptions \
 // RUN:     -mllvm -enable-emscripten-cxx-exceptions 2>&1 \
 // RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_EMSCRIPTEN_EH %s
 // WASM_EXCEPTIONS_EMSCRIPTEN_EH: invalid argument '-fwasm-exceptions' not allowed with '-mllvm -enable-emscripten-cxx-exceptions'
 
-// '-mllvm -wasm-enable-sjlj' sets +exception-handling and
-// '-exception-model=wasm'
+// '-fwasm-exceptions' not allowed with '-mno-multivalue'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -fwasm-exceptions -mno-multivalue 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_NO_MULTIVALUE %s
+// WASM_EXCEPTIONS_NO_MULTIVALUE: invalid argument '-fwasm-exceptions' not allowed with '-mno-multivalue'
+
+// '-fwasm-exceptions' not allowed with '-mno-reference-types'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -fwasm-exceptions -mno-reference-types 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_EXCEPTIONS_NO_REFERENCE_TYPES %s
+// WASM_EXCEPTIONS_NO_REFERENCE_TYPES: invalid argument '-fwasm-exceptions' not allowed with '-mno-reference-types'
+
+// '-mllvm -wasm-enable-sjlj' sets +exception-handling, +multivalue,
+// +reference-types  and '-exception-model=wasm'
 // RUN: %clang -### --target=wasm32-unknown-unknown \
 // RUN:    --sysroot=/foo %s -mllvm -wasm-enable-sjlj 2>&1 \
 // RUN:  | FileCheck -check-prefix=WASM_SJLJ %s
-// WASM_SJLJ: "-cc1" {{.*}} "-target-feature" "+exception-handling" "-exception-model=wasm"
+// WASM_SJLJ: "-cc1" {{.*}} "-target-feature" "+exception-handling" "-exception-model=wasm" "-target-feature" "+multivalue" "-target-feature" "+reference-types"
 
 // '-mllvm -wasm-enable-sjlj' not allowed with '-mno-exception-handling'
 // RUN: not %clang -### --target=wasm32-unknown-unknown \
@@ -168,6 +182,19 @@
 // RUN:   | FileCheck -check-prefix=WASM_SJLJ_EMSCRIPTEN_SJLJ %s
 // WASM_SJLJ_EMSCRIPTEN_SJLJ: invalid argument '-mllvm -wasm-enable-sjlj' not allowed with '-mllvm -enable-emscripten-sjlj'
 
+// '-mllvm -wasm-enable-sjlj' not allowed with '-mno-multivalue'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -mllvm -wasm-enable-sjlj -mno-multivalue 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_SJLJ_NO_MULTIVALUE %s
+// WASM_SJLJ_NO_MULTIVALUE: invalid argument '-mllvm -wasm-enable-sjlj' not allowed with '-mno-multivalue'
+
+// '-mllvm -wasm-enable-sjlj' not allowed with '-mno-reference-types'
+// RUN: not %clang -### --target=wasm32-unknown-unknown \
+// RUN:     --sysroot=/foo %s -mllvm -wasm-enable-sjlj \
+// RUN:     -mno-reference-types 2>&1 \
+// RUN:   | FileCheck -check-prefix=WASM_SJLJ_NO_REFERENCE_TYPES %s
+// WASM_SJLJ_NO_REFERENCE_TYPES: invalid argument '-mllvm -wasm-enable-sjlj' not allowed with '-mno-reference-types'
+
 // 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"