Bug 1521058 - Baldr: fix IDB deserialization flags on arm64 (r=lth)

#include "js/BuildId.h"  // JS::BuildIdCharVector

#include "threading/LockGuard.h"

#include "util/NSPR.h"

#include "wasm/WasmBaselineCompile.h"

#include "wasm/WasmCompile.h"

#include "wasm/WasmInstance.h"

#include "wasm/WasmIonCompile.h"

#include "wasm/WasmJS.h"

#include "wasm/WasmSerialize.h"

RefPtr<JS::WasmModule> wasm::DeserializeModule(PRFileDesc* bytecodeFile,

                                               UniqueChars filename,

                                               unsigned line) {

  // We have to compile new code here so if we're fundamentally unable to

  // compile, we have to fail.

  if (!BaselineCanCompile() && !IonCanCompile()) {

    return nullptr;

  }

  PRFileInfo bytecodeInfo;

  UniqueMapping bytecodeMapping = MapFile(bytecodeFile, &bytecodeInfo);

  if (!bytecodeMapping) {

    return nullptr;

  }

  // The true answer to whether shared memory is enabled is provided by

  // cx->realm()->creationOptions().getSharedMemoryAndAtomicsEnabled()

  // where cx is the context that originated the call that caused this

  // deserialization attempt to happen.  We don't have that context here, so

  // we assume that shared memory is enabled; we will catch a wrong assumption

  // later, during instantiation.

  // The true answer to whether various flags are enabled is provided by

  // the JSContext that originated the call that caused this deserialization

  // attempt to happen. We don't have that context here, so we assume that

  // shared memory is enabled; we will catch a wrong assumption later, during

  // instantiation.

  //

  // (We would prefer to store this value with the Assumptions when

  // serializing, and for the caller of the deserialization machinery to

  // provide the value from the originating context.)

  args->ionEnabled = true;

  args->baselineEnabled = true;

  args->sharedMemoryEnabled = true;

  UniqueChars error;