[WebAssebmly][MC] Support .import_name/.import_field asm directives

Convert the MC test to use asm rather than bitcode.

This is a precursor to https://reviews.llvm.org/D70520.

Differential Revision: https://reviews.llvm.org/D70877

include/llvm/MC/MCSymbolWasm.h

@@ -78,6 +78,7 @@ public:
   }
   void setImportModule(StringRef Name) { ImportModule = Name; }
 
+  bool hasImportName() const { return ImportName.hasValue(); }
   const StringRef getImportName() const {
       if (ImportName.hasValue()) {
           return ImportName.getValue();

lib/MC/WasmObjectWriter.cpp

@@ -1452,7 +1452,7 @@ uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm,
         Flags |= wasm::WASM_SYMBOL_EXPORTED;
       }
     }
-    if (WS.getName() != WS.getImportName())
+    if (WS.hasImportName())
       Flags |= wasm::WASM_SYMBOL_EXPLICIT_NAME;
 
     wasm::WasmSymbolInfo Info;

lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp

@@ -712,6 +712,30 @@ public:
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
+    if (DirectiveID.getString() == ".import_module") {
+      auto SymName = expectIdent();
+      if (SymName.empty())
+        return true;
+      if (expect(AsmToken::Comma, ","))
+        return true;
+      auto ImportModule = expectIdent();
+      auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
+      WasmSym->setImportModule(ImportModule);
+      TOut.emitImportModule(WasmSym, ImportModule);
+    }
+
+    if (DirectiveID.getString() == ".import_name") {
+      auto SymName = expectIdent();
+      if (SymName.empty())
+        return true;
+      if (expect(AsmToken::Comma, ","))
+        return true;
+      auto ImportName = expectIdent();
+      auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
+      WasmSym->setImportName(ImportName);
+      TOut.emitImportName(WasmSym, ImportName);
+    }
+
     if (DirectiveID.getString() == ".eventtype") {
       auto SymName = expectIdent();
       if (SymName.empty())

test/MC/WebAssembly/import-module.ll

@@ -1,31 +0,0 @@
-; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
-
-target triple = "wasm32-unknown-unknown"
-
-define void @test() {
-  call void @foo()
-  call void @plain()
-  ret void
-}
-
-declare void @foo() #0
-declare void @plain()
-
-attributes #0 = { "wasm-import-module"="bar" "wasm-import-name"="qux" }
-
-; CHECK:        - Type:            IMPORT
-; CHECK-NEXT:     Imports:
-; CHECK:            - Module:          bar
-; CHECK-NEXT:         Field:           qux
-; CHECK-NEXT:         Kind:            FUNCTION
-
-; CHECK:            - Module:          env
-; CHECK-NEXT:         Field:           plain
-; CHECK-NEXT:         Kind:            FUNCTION
-
-; CHECK:        - Type:            CUSTOM
-; CHECK:              Name:            foo
-; CHECK-NEXT:         Flags:           [ UNDEFINED, EXPLICIT_NAME ]
-
-; CHECK:              Name:            plain
-; CHECK-NEXT:         Flags:           [ UNDEFINED ]

test/MC/WebAssembly/import-module.s

@@ -0,0 +1,33 @@
+# RUN: llvm-mc -triple=wasm32 < %s | FileCheck %s -check-prefix=CHECK-ASM
+# RUN: llvm-mc -triple=wasm32 -filetype=obj -o - < %s | obj2yaml | FileCheck %s
+
+test:
+  .functype test () -> ()
+  call      foo
+  call      plain
+  end_function
+
+  .functype foo () -> ()
+  .functype plain () -> ()
+  .import_module  foo, bar
+  .import_name  foo, qux
+
+# CHECK-ASM: .import_module  foo, bar
+# CHECK-ASM: .import_name  foo, qux
+
+# CHECK:        - Type:            IMPORT
+# CHECK-NEXT:     Imports:
+# CHECK:            - Module:          bar
+# CHECK-NEXT:         Field:           qux
+# CHECK-NEXT:         Kind:            FUNCTION
+
+# CHECK:            - Module:          env
+# CHECK-NEXT:         Field:           plain
+# CHECK-NEXT:         Kind:            FUNCTION
+
+# CHECK:        - Type:            CUSTOM
+# CHECK:              Name:            foo
+# CHECK-NEXT:         Flags:           [ UNDEFINED, EXPLICIT_NAME ]
+
+# CHECK:              Name:            plain
+# CHECK-NEXT:         Flags:           [ UNDEFINED ]