WebAssembly: Move runtime libcall setting out of TargetLowering

RuntimeLibcallInfo needs to be correct outside of codegen contexts.

Author: arsenm

llvm/lib/IR/RuntimeLibcalls.cpp

@@ -277,5 +277,10 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
       setLibcallName(RTLIB::MULO_I64, nullptr);
     }
     setLibcallName(RTLIB::MULO_I128, nullptr);
+  } else {
+    // Define the emscripten name for return address helper.
+    // TODO: when implementing other Wasm backends, make this generic or only do
+    // this on emscripten depending on what they end up doing.
+    setLibcallName(RTLIB::RETURN_ADDRESS, "emscripten_return_address");
   }
 }

llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp

@@ -385,11 +385,6 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
 
   setMaxAtomicSizeInBitsSupported(64);
 
-  // Define the emscripten name for return address helper.
-  // TODO: when implementing other Wasm backends, make this generic or only do
-  // this on emscripten depending on what they end up doing.
-  setLibcallName(RTLIB::RETURN_ADDRESS, "emscripten_return_address");
-
   // Always convert switches to br_tables unless there is only one case, which
   // is equivalent to a simple branch. This reduces code size for wasm, and we
   // defer possible jump table optimizations to the VM.