diff --git a/js/src/jit-test/tests/asm.js/testBug1359612.js b/js/src/jit-test/tests/asm.js/testBug1359612.js
new file mode 100644
index 000000000000..f2a2255322b6
--- /dev/null
+++ b/js/src/jit-test/tests/asm.js/testBug1359612.js
@@ -0,0 +1,9 @@
+load(libdir + 'asm.js');
+
+asmLink(asmCompile('stdlib', 'foreign', USE_ASM + `
+  var ff = foreign.ff;
+  function f() {
+      ff(+1);
+  }
+  return f
+`), this, { ff: Math.log1p });
diff --git a/js/src/jit-test/tests/wasm/regress/builtin-import-sigs.js b/js/src/jit-test/tests/wasm/regress/builtin-import-sigs.js
new file mode 100644
index 000000000000..a23dd9ddc41c
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/regress/builtin-import-sigs.js
@@ -0,0 +1,15 @@
+var code = wasmTextToBinary(`(module
+    (import $one "" "builtin")
+    (import $two "" "builtin" (param i32))
+    (import $three "" "builtin" (result i32))
+    (import $four "" "builtin" (result f32) (param f32 f32 f32 f32 f32 f32 f32 f32 f32 f32 f32 f32))
+    (func (export "run")
+        (call $one)
+        (call $two (i32.const 0))
+        (drop (call $three))
+        (drop (call $four (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0) (f32.const 0)))
+    )
+)`);
+var m = new WebAssembly.Module(code);
+var i = new WebAssembly.Instance(m, {'':{builtin:Math.sin}});
+i.exports.run();
diff --git a/js/src/wasm/WasmBuiltins.cpp b/js/src/wasm/WasmBuiltins.cpp
index ca8040a813ba..1c6d220ae21d 100644
--- a/js/src/wasm/WasmBuiltins.cpp
+++ b/js/src/wasm/WasmBuiltins.cpp
@@ -904,8 +904,8 @@ wasm::SymbolicAddressTarget(SymbolicAddress sym)
     return thunks.codeBase + thunks.codeRanges[codeRangeIndex].begin();
 }
 
-static ABIFunctionType
-ToABIFunctionType(const Sig& sig)
+static Maybe<ABIFunctionType>
+ToBuiltinABIFunctionType(const Sig& sig)
 {
     const ValTypeVector& args = sig.args();
     ExprType ret = sig.ret();
@@ -914,18 +914,21 @@ ToABIFunctionType(const Sig& sig)
     switch (ret) {
       case ExprType::F32: abiType = ArgType_Float32 << RetType_Shift; break;
       case ExprType::F64: abiType = ArgType_Double << RetType_Shift; break;
-      default:            MOZ_CRASH("unhandled ret type");
+      default: return Nothing();
     }
 
+    if ((args.length() + 1) > (sizeof(uint32_t) * 8 / ArgType_Shift))
+        return Nothing();
+
     for (size_t i = 0; i < args.length(); i++) {
         switch (args[i]) {
           case ValType::F32: abiType |= (ArgType_Float32 << (ArgType_Shift * (i + 1))); break;
           case ValType::F64: abiType |= (ArgType_Double << (ArgType_Shift * (i + 1))); break;
-          default:           MOZ_CRASH("unhandled arg type");
+          default: return Nothing();
         }
     }
 
-    return ABIFunctionType(abiType);
+    return Some(ABIFunctionType(abiType));
 }
 
 void*
@@ -936,9 +939,11 @@ wasm::MaybeGetBuiltinThunk(HandleFunction f, const Sig& sig, JSContext* cx)
     if (!f->isNative() || !f->jitInfo() || f->jitInfo()->type() != JSJitInfo::InlinableNative)
         return nullptr;
 
-    InlinableNative native = f->jitInfo()->inlinableNative;
-    ABIFunctionType abiType = ToABIFunctionType(sig);
-    TypedNative typedNative(native, abiType);
+    Maybe<ABIFunctionType> abiType = ToBuiltinABIFunctionType(sig);
+    if (!abiType)
+        return nullptr;
+
+    TypedNative typedNative(f->jitInfo()->inlinableNative, *abiType);
 
     const BuiltinThunks& thunks = *builtinThunks;
     auto p = thunks.typedNativeToCodeRange.readonlyThreadsafeLookup(typedNative);