[WebAssembly] Add an import_module function attribute

This adds a C/C++ attribute which corresponds to the LLVM IR wasm-import-module
attribute. It allows code to specify an explicit import module.

Differential Revision: https://reviews.llvm.org/D57160

llvm-svn: 352106

1 files changed, 25 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index cf7e97a67b0..24e07599186 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5709,6 +5709,28 @@ static void handleAVRSignalAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   handleSimpleAttribute<AVRSignalAttr>(S, D, AL);
 }
 
+static void handleWebAssemblyImportModuleAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'import_module'" << ExpectedFunction;
+    return;
+  }
+
+  auto *FD = cast<FunctionDecl>(D);
+  if (FD->isThisDeclarationADefinition()) {
+    S.Diag(D->getLocation(), diag::err_alias_is_definition) << FD << 0;
+    return;
+  }
+
+  StringRef Str;
+  SourceLocation ArgLoc;
+  if (!S.checkStringLiteralArgumentAttr(AL, 0, Str, &ArgLoc))
+    return;
+
+  FD->addAttr(::new (S.Context) WebAssemblyImportModuleAttr(
+      AL.getRange(), S.Context, Str,
+      AL.getAttributeSpellingListIndex()));
+}
 
 static void handleRISCVInterruptAttr(Sema &S, Decl *D,
                                      const ParsedAttr &AL) {
@@ -6464,6 +6486,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case ParsedAttr::AT_AVRSignal:
     handleAVRSignalAttr(S, D, AL);
     break;
+  case ParsedAttr::AT_WebAssemblyImportModule:
+    handleWebAssemblyImportModuleAttr(S, D, AL);
+    break;
   case ParsedAttr::AT_IBAction:
     handleSimpleAttribute<IBActionAttr>(S, D, AL);
     break;