[WebAssembly] Enable multivalue and reference-types in generic CPU config (#80923)

This enables multivalue and reference-types in `-mcpu=generic`           
configuration. These proposals have been standardized and supported in   
all major browsers for several years at this point:                      
https://github.com/WebAssembly/proposals/blob/main/finished-proposals.md

Author: aheejin

clang/docs/ReleaseNotes.rst

@@ -718,6 +718,11 @@ AIX Support
 WebAssembly Support
 ^^^^^^^^^^^^^^^^^^^
 
+The -mcpu=generic configuration now enables multivalue and reference-types.These
+proposals are standardized and available in all major engines. Enabling
+multivalue here only enables the language feature but does not turn on the
+multivalue ABI (this enables non-ABI uses of multivalue, like exnref).
+
 AVR Support
 ^^^^^^^^^^^
 

clang/lib/Basic/Targets/WebAssembly.cpp

@@ -148,20 +148,26 @@ void WebAssemblyTargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
 bool WebAssemblyTargetInfo::initFeatureMap(
     llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
     const std::vector<std::string> &FeaturesVec) const {
-  if (CPU == "bleeding-edge") {
+  auto addGenericFeatures = [&]() {
+    Features["multivalue"] = true;
+    Features["mutable-globals"] = true;
+    Features["reference-types"] = true;
+    Features["sign-ext"] = true;
+  };
+  auto addBleedingEdgeFeatures = [&]() {
+    addGenericFeatures();
     Features["atomics"] = true;
     Features["bulk-memory"] = true;
     Features["multimemory"] = true;
-    Features["mutable-globals"] = true;
     Features["nontrapping-fptoint"] = true;
-    Features["reference-types"] = true;
-    Features["sign-ext"] = true;
     Features["tail-call"] = true;
     Features["half-precision"] = true;
     setSIMDLevel(Features, SIMD128, true);
-  } else if (CPU == "generic") {
-    Features["mutable-globals"] = true;
-    Features["sign-ext"] = true;
+  };
+  if (CPU == "generic") {
+    addGenericFeatures();
+  } else if (CPU == "bleeding-edge") {
+    addBleedingEdgeFeatures();
   }
 
   return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);

clang/test/Preprocessor/wasm-target-features.c

@@ -152,7 +152,9 @@
 // RUN:     -target wasm64-unknown-unknown -mcpu=generic \
 // RUN:   | FileCheck %s -check-prefix=GENERIC-INCLUDE
 //
+// GENERIC-INCLUDE-DAG: #define __wasm_multivalue__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_mutable_globals__ 1{{$}}
+// GENERIC-INCLUDE-DAG: #define __wasm_reference_types__ 1{{$}}
 // GENERIC-INCLUDE-DAG: #define __wasm_sign_ext__ 1{{$}}
 //
 // RUN: %clang -E -dM %s -o - 2>&1 \
@@ -167,9 +169,7 @@
 // GENERIC-NOT: #define __wasm_exception_handling__ 1{{$}}
 // GENERIC-NOT: #define __wasm_extended_const__ 1{{$}}
 // GENERIC-NOT: #define __wasm_multimemory__ 1{{$}}
-// GENERIC-NOT: #define __wasm_multivalue__ 1{{$}}
 // GENERIC-NOT: #define __wasm_nontrapping_fptoint__ 1{{$}}
-// GENERIC-NOT: #define __wasm_reference_types__ 1{{$}}
 // GENERIC-NOT: #define __wasm_relaxed_simd__ 1{{$}}
 // GENERIC-NOT: #define __wasm_simd128__ 1{{$}}
 // GENERIC-NOT: #define __wasm_tail_call__ 1{{$}}
@@ -184,6 +184,7 @@
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_atomics__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_bulk_memory__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_multimemory__ 1{{$}}
+// BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_multivalue__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_mutable_globals__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_nontrapping_fptoint__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_reference_types__ 1{{$}}
@@ -200,7 +201,6 @@
 //
 // BLEEDING-EDGE-NOT: #define __wasm_exception_handling__ 1{{$}}
 // BLEEDING-EDGE-NOT: #define __wasm_extended_const__ 1{{$}}
-// BLEEDING-EDGE-NOT: #define __wasm_multivalue__ 1{{$}}
 // BLEEDING-EDGE-NOT: #define __wasm_relaxed_simd__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \