deps/v8/src/objects.h:3263:46: error: invalid use of incomplete type ‘class v8::internal::Heap

[octoploid]

• Version:
• Platform:
• Subsystem:

Compilation fails with gcc-7:

 % g++ '-DV8_TARGET_ARCH_X64' '-DENABLE_DISASSEMBLER' '-DV8_I18N_SUPPORT' -I../deps/v8 -I../. -pthread -Wall -Wextra -Wno-unused-parameter -m64 -fno-strict-aliasing -m64 -fdata-sections -ffunction-sections -O3 -O3 -fno-omit-frame-pointer -fno-rtti -fno-exceptions -std=gnu++0x -MMD -MF /home/markus/tmp/node/out/Release/.deps//home/markus/tmp/node/out/Release/obj.target/v8_nosnapshot/gen/libraries.o.d.raw -c -o /home/markus/tmp/node/out/Release/obj.target/v8_nosnapshot/gen/libraries.o /home/markus/tmp/node/out/Release/obj/gen/libraries.cc

In file included from ../deps/v8/src/snapshot/natives.h:8:0,
                 from /home/markus/tmp/node/out/Release/obj/gen/libraries.cc:8:
../deps/v8/src/objects.h: In member function ‘uint32_t v8::internal::HashTable<Derived, Shape, Key>::Hash(Key)’:
../deps/v8/src/objects.h:3263:46: error: invalid use of incomplete type ‘class v8::internal::Heap’
       return Shape::SeededHash(key, GetHeap()->HashSeed());
                                              ^~
In file included from ../deps/v8/src/v8.h:8:0,
                 from /home/markus/tmp/node/out/Release/obj/gen/libraries.cc:7:
../deps/v8/include/v8.h:149:7: note: forward declaration of ‘class v8::internal::Heap’
 class Heap;
       ^~~~
In file included from ../deps/v8/src/snapshot/natives.h:8:0,
                 from /home/markus/tmp/node/out/Release/obj/gen/libraries.cc:8:
../deps/v8/src/objects.h: In member function ‘uint32_t v8::internal::HashTable<Derived, Shape, Key>::HashForObject(Key, v8::internal::Object*)’:
../deps/v8/src/objects.h:3271:55: error: invalid use of incomplete type ‘class v8::internal::Heap’
       return Shape::SeededHashForObject(key, GetHeap()->HashSeed(), object);
                                                       ^~
In file included from ../deps/v8/src/v8.h:8:0,
                 from /home/markus/tmp/node/out/Release/obj/gen/libraries.cc:7:
../deps/v8/include/v8.h:149:7: note: forward declaration of ‘class v8::internal::Heap’
 class Heap;
       ^~~~

The code is ill formed (no diagnostic required) according the C++ standard.

[targos]

cc @nodejs/v8

[mscdex]

@octoploid What node version?

[octoploid]

Latest git branch master.

[gibfahn]

@octoploid what platform are you on?

[jeisinger]

/cc @hashseed

[octoploid]

I'm running Linux. Let me quote the C++ std:

14.6/8: "If a hypothetical instantiation of a template immediately following its definition would be ill-formed due to a construct that does not depend on a template parameter, the program is ill-formed; no diagnostic is required. If the interpretation of such a construct in the hypothetical instantiation is different from the interpretation of the corresponding construct in any actual instantiation of the template, the program is ill-formed; no diagnostic is required.
[ Note: This can happen in situations including the following: * a type used in a non-dependent name is incomplete at the point at which a template is defined but is complete at the point at which an instantiation is performed, ....

[octoploid]

 % cat tc.ii
class Heap;
class A {
public:
  Heap *m_fn1();
};
template <typename> class B : A {
  void m_fn2() { m_fn1()->HashSeed; }
};
 
% g++ -c tc.ii
tc.ii: In member function ‘void B< <template-parameter-1-1> >::m_fn2()’:
tc.ii:7:25: error: invalid use of incomplete type ‘class Heap’
   void m_fn2() { m_fn1()->HashSeed; }
                         ^~
tc.ii:1:7: note: forward declaration of ‘class Heap’
 class Heap;
       ^~~~

[hashseed]

it should work by including heap.h into natives.h?

[sgallagher]

For the record, just including heap.h (or heap.h plus heap-inl.h) into natives.h does not result in a successful build.

Example: https://kojipkgs.fedoraproject.org//work/tasks/8811/17888811/build.log (note: this is a transient build and will be reaped in seven days)

[kasicka]

Can someone take a look on this already?
New logs:
6.9.5: https://fedorapeople.org/~zvetlik/buildlogs/v695-gcc701build.log
6.10.0: https://fedorapeople.org/~zvetlik/buildlogs/v6100-gcc701build.log

[hashseed]

Some small refactoring to move the code out of objects.h into objects-inl.h should hopefully fix this issue. I'll come up with a patch tomorrow.