[WebAssembly] Move getLibcallSignature into WebAssembly namespace (NFC) (#85171)

These are Wasm only functions so they are better be within `WebAssembly`
namespace rather than the `llvm` namespace which includes the whole
LLVM.

Also this removes `extern` keywords which are not strictly necessary.

Author: aheejin

llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

@@ -264,7 +264,7 @@ MCSymbol *WebAssemblyAsmPrinter::getOrCreateWasmSymbol(StringRef Name) {
     Params.push_back(AddrType);
   } else { // Function symbols
     WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
-    getLibcallSignature(Subtarget, Name, Returns, Params);
+    WebAssembly::getLibcallSignature(Subtarget, Name, Returns, Params);
   }
   auto Signature = std::make_unique<wasm::WasmSignature>(std::move(Returns),
                                                          std::move(Params));

llvm/lib/Target/WebAssembly/WebAssemblyRuntimeLibcallSignatures.cpp

@@ -524,10 +524,10 @@ struct StaticLibcallNameMap {
 
 } // end anonymous namespace
 
-void llvm::getLibcallSignature(const WebAssemblySubtarget &Subtarget,
-                               RTLIB::Libcall LC,
-                               SmallVectorImpl<wasm::ValType> &Rets,
-                               SmallVectorImpl<wasm::ValType> &Params) {
+void WebAssembly::getLibcallSignature(const WebAssemblySubtarget &Subtarget,
+                                      RTLIB::Libcall LC,
+                                      SmallVectorImpl<wasm::ValType> &Rets,
+                                      SmallVectorImpl<wasm::ValType> &Params) {
   assert(Rets.empty());
   assert(Params.empty());
 
@@ -889,10 +889,10 @@ void llvm::getLibcallSignature(const WebAssemblySubtarget &Subtarget,
 
 // TODO: If the RTLIB::Libcall-taking flavor of GetSignature remains unused
 // other than here, just roll its logic into this version.
-void llvm::getLibcallSignature(const WebAssemblySubtarget &Subtarget,
-                               StringRef Name,
-                               SmallVectorImpl<wasm::ValType> &Rets,
-                               SmallVectorImpl<wasm::ValType> &Params) {
+void WebAssembly::getLibcallSignature(const WebAssemblySubtarget &Subtarget,
+                                      StringRef Name,
+                                      SmallVectorImpl<wasm::ValType> &Rets,
+                                      SmallVectorImpl<wasm::ValType> &Params) {
   static StaticLibcallNameMap LibcallNameMap;
   auto &Map = LibcallNameMap.Map;
   auto Val = Map.find(Name);

llvm/lib/Target/WebAssembly/WebAssemblyRuntimeLibcallSignatures.h

@@ -22,16 +22,18 @@ namespace llvm {
 
 class WebAssemblySubtarget;
 
-extern void getLibcallSignature(const WebAssemblySubtarget &Subtarget,
-                                RTLIB::Libcall LC,
-                                SmallVectorImpl<wasm::ValType> &Rets,
-                                SmallVectorImpl<wasm::ValType> &Params);
+namespace WebAssembly {
 
-extern void getLibcallSignature(const WebAssemblySubtarget &Subtarget,
-                                StringRef Name,
-                                SmallVectorImpl<wasm::ValType> &Rets,
-                                SmallVectorImpl<wasm::ValType> &Params);
+void getLibcallSignature(const WebAssemblySubtarget &Subtarget,
+                         RTLIB::Libcall LC,
+                         SmallVectorImpl<wasm::ValType> &Rets,
+                         SmallVectorImpl<wasm::ValType> &Params);
 
+void getLibcallSignature(const WebAssemblySubtarget &Subtarget, StringRef Name,
+                         SmallVectorImpl<wasm::ValType> &Rets,
+                         SmallVectorImpl<wasm::ValType> &Params);
+
+} // end namespace WebAssembly
 } // end namespace llvm
 
 #endif