CanImport: allow using string literal to indicate desired version

Author: nkcsgexi

lib/Parse/ParseIfConfig.cpp

@@ -98,12 +98,17 @@ static llvm::VersionTuple getCanImportVersion(TupleExpr *te,
     }
     return result;
   }
+  StringRef verText;
   if (auto *nle = dyn_cast<NumberLiteralExpr>(subE)) {
-    auto digits = nle->getDigitsText();
-    if (result.tryParse(digits)) {
-      if (D) {
-        D->diagnose(nle->getLoc(), diag::canimport_version, digits);
-      }
+    verText = nle->getDigitsText();
+  } else if (auto *sle= dyn_cast<StringLiteralExpr>(subE)) {
+    verText = sle->getValue();
+  }
+  if (verText.empty())
+    return result;
+  if (result.tryParse(verText)) {
+    if (D) {
+      D->diagnose(subE->getLoc(), diag::canimport_version, verText);
     }
   }
   return result;

test/Parse/versioned_canimport.swift

@@ -56,3 +56,21 @@ func canImportVersioned() {
   let h = 1 // expected-warning {{initialization of immutable value 'h' was never used; consider replacing with assignment to '_' or removing it}}
 #endif
 }
+
+func canImportVersionedString() {
+#if canImport(Foo, _version: "113.331")
+  let a = 1
+#endif
+
+#if canImport(Foo, _version: "113.3000")
+  let b = 1
+#endif
+
+#if canImport(Foo, _version: "4")
+  let d = 1 // expected-warning {{initialization of immutable value 'd' was never used; consider replacing with assignment to '_' or removing it}}
+#endif
+
+#if canImport(Foo, _version: "113.33")
+  let e = 1 // expected-warning {{initialization of immutable value 'e' was never used; consider replacing with assignment to '_' or removing it}}
+#endif
+}