Warn if linking section is present, as we cannot handle it yet (#1798)

Author: kripken

src/wasm-binary.h

@@ -341,8 +341,8 @@ enum EncodedType {
 namespace UserSections {
 extern const char* Name;
 extern const char* SourceMapUrl;
-
 extern const char* Dylink;
+extern const char* Linking;
 
 enum Subsection {
   NameFunction = 1,

src/wasm/wasm-binary.cpp

@@ -713,6 +713,9 @@ void WasmBinaryBuilder::readUserSection(size_t payloadLen) {
     readNames(payloadLen - (pos - oldPos));
   } else {
     // an unfamiliar custom section
+    if (sectionName.equals(BinaryConsts::UserSections::Linking)) {
+      std::cerr << "warning: linking section is present, which binaryen cannot handle yet - relocations will be invalidated!\n";
+    }
     wasm.userSections.resize(wasm.userSections.size() + 1);
     auto& section = wasm.userSections.back();
     section.name = sectionName.str;

src/wasm/wasm.cpp

@@ -29,8 +29,8 @@ namespace BinaryConsts {
 namespace UserSections {
 const char* Name = "name";
 const char* SourceMapUrl = "sourceMappingURL";
-
 const char* Dylink = "dylink";
+const char* Linking = "linking";
 }
 }