WebAssembly tables cannot be declared in non-global scope

[feedab1e]

While a declaration like the following is accepted by the compiler:

static __externref_t table[0];

the same declaration in a namespace is not (link):

namespace foo {
    static __externref_t table1[0];
};

produces

<source>:2:26: error: WebAssembly table cannot be declared within a function
    2 |     static __externref_t table1[0];
      |                          ^
1 error generated.
Compiler returned: 1

which is a fairly strange diagnostic considering that the declaration is not in a function.

The same issue occurs when trying to declare a table as a static member of a class or inside a function (link):

struct bar {
    static __externref_t table2[0];
};
void baz() {
    static __externref_t table3[0];
}

produces

<source>:2:26: error: WebAssembly table cannot be declared within a function
    2 |     static __externref_t table2[0];
      |                          ^
<source>:5:26: error: WebAssembly table cannot be declared within a function
    5 |     static __externref_t table3[0];
      |                          ^

Even though the last diagnostic is right in that the declaration is in a function, I don't see a reason why this shouldn't be allowed.

[llvmbot]

@llvm/issue-subscribers-backend-webassembly

Author: None (feedab1e)

While a declaration like the following is accepted by the compiler: ```cpp static __externref_t table[0]; ``` the same declaration in a namespace is not ([link](https://gcc.godbolt.org/z/qWbcfTj6E)): ```cpp namespace foo { static __externref_t table1[0]; }; ``` produces ``` <source>:2:26: error: WebAssembly table cannot be declared within a function 2 | static __externref_t table1[0]; | ^ 1 error generated. Compiler returned: 1 ``` which is a fairly strange diagnostic considering that the declaration is not in a function.

The same issue occurs when trying to declare a table as a static member of a class or inside a function (link):

struct bar {
    static __externref_t table2[0];
};
void baz() {
    static __externref_t table3[0];
}

produces

<source>:2:26: error: WebAssembly table cannot be declared within a function
    2 |     static __externref_t table2[0];
      |                          ^
<source>:5:26: error: WebAssembly table cannot be declared within a function
    5 |     static __externref_t table3[0];
      |                          ^

Even though the last diagnostic is right in that the declaration is in a function, I don't see a reason why this shouldn't be allowed.

[sbc100]

Not much work has been done on supporting externref / table over the last year or so. If you are using this feature perhaps you would be able to work on it. I don't know of anyone currently using it or working on it.