1039964 - undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::trace(JSTracer*) when building with --enable-shared-js

Status: NEW

(Core :: JavaScript Engine, defect)

Description

[Mike Hommey [:glandium]]

../../../dom/bindings/Unified_cpp_dom_bindings0.o: In function `TraceSelf':
/home/glandium/mozilla-central/js/xpconnect/src/xpcprivate.h:1071: undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::trace(JSTracer*)'
../../../js/xpconnect/src/Unified_cpp_js_xpconnect_src1.o: In function `~XPCWrappedNativeScope':
/home/glandium/mozilla-central/js/xpconnect/src/XPCWrappedNativeScope.cpp:404: undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::destroy()'
../../../js/xpconnect/src/Unified_cpp_js_xpconnect_src1.o: In function `initialized':
/home/glandium/build/obj-x86_64-unknown-linux-gnu/js/xpconnect/src/../../../dist/include/js/WeakMapPtr.h:(.text._ZN21XPCWrappedNativeScope15GetExpandoChainEN2JS6HandleIP8JSObjectEE+0xc): undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::lookup(JSObject* const&)'
../../../js/xpconnect/src/Unified_cpp_js_xpconnect_src1.o: In function `SetExpandoChain':
/home/glandium/mozilla-central/js/xpconnect/src/XPCWrappedNativeScope.cpp:703: undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::init(JSContext*)'
/home/glandium/mozilla-central/js/xpconnect/src/XPCWrappedNativeScope.cpp:705: undefined reference to `JS::WeakMapPtr<JSObject*, JSObject*>::put(JSContext*, JSObject* const&, JSObject* const&)'
/usr/bin/ld: libxul.so: hidden symbol `_ZN2JS10WeakMapPtrIP8JSObjectS2_E4initEP9JSContext' isn't defined

WeakMapPtr is declared visible, but as I understand it, the fact that JSObject is not visible makes the symbols hidden.

A minimal testcase is as follows:

#pragma GCC visibility push(hidden)

class A;

template <class T>
class __attribute__((visibility("default"))) B {
public:
  void init(T *t) { }
};


void foo(A *a) {
  B<A> b;
  b.init(a);
}

This results in the _ZN1BI1AE4initEPS0_ symbol being hidden.

While --enable-shared-js is not really a supported option for Linux or Mac, it is useful to make incremental builds faster, and is also helpful to test a kind-of-like Windows setup on Linux when working on the build system.

Comment 1

[Mike Hommey [:glandium]]

And it works on Windows because dllexport on the template doesn't have the same restriction.

Comment 2

[Boris Zbarsky [:bzbarsky]]

--enable-shared-js is also very useful for profiling.

Comment 3

[Mike Hommey [:glandium]]

Attachment: Possible patch

This worked for me, but this has the unpleasant side effect of making JSObject functions public when they weren't before.

Comment 4

[Mike Hommey [:glandium]]

Please note I won't be actively working on this bug despite having attached a working hackish patch.

Comment 5

[Mike Hommey [:glandium]]

Also note that it's hackish *and* dangerous. I'm sure there are possible problems with JSObject not being declared visible in jsobj.h (that is, some files would think it's hidden and others it's visible).