Fix the false warning
> incompatible pointer types passing 'va_list' (aka '__builtin_va_list')
to parameter of type 'struct __va_list_tag *'
[-Wincompatible-pointer-types]
The warning is wrong because both in the function declaration and at the
call site we are using `va_list`.
When we call `ASTContext::getBuiltinVaListDecl` at a specific moment, we
end up re-entering this function which causes creating 2 instances of
`BuiltinVaListDecl` and 2 instances of `VaListTagDecl` but the stored
instances are unrelated to each other because of the call sequence like
getBuiltinVaListDecl
CreateX86_64ABIBuiltinVaListDecl
VaListTagDecl = TagA
indirectly call getBuiltinVaListDecl
CreateX86_64ABIBuiltinVaListDecl
VaListTagDecl = TagB
BuiltinVaListDecl = ListB
BuiltinVaListDecl = ListA
Now we have `BuiltinVaListDecl == ListA` and `VaListTagDecl == TagB`.
For x86_64 '__builtin_va_list' and 'struct __va_list_tag *' are
compatible because '__builtin_va_list' == '__va_list_tag[1]'. But
because we have unrelated decls for VaListDecl and VaListTagDecl the
types are considered incompatible as we are comparing type pointers.
Fix the error by creating `BuiltinVaListDecl` before
`ASTReader::InitializeSema`, so that during
`ASTContext::getBuiltinVaListDecl` ASTReader doesn't try to de-serialize
'__builtin_va_list' and to call `ASTContext::getBuiltinVaListDecl`
again.
Reland with the requirement to have x86 target to avoid errors like
> error: unable to create target: 'No available targets are compatible
with triple "x86_64-apple-darwin"'
rdar://130947515
Fix the false warning
> incompatible pointer types passing 'va_list' (aka '__builtin_va_list')
to parameter of type 'struct __va_list_tag *'
[-Wincompatible-pointer-types]
The warning is wrong because both in the function declaration and at the
call site we are using `va_list`.
When we call `ASTContext::getBuiltinVaListDecl` at a specific moment, we
end up re-entering this function which causes creating 2 instances of
`BuiltinVaListDecl` and 2 instances of `VaListTagDecl` but the stored
instances are unrelated to each other because of the call sequence like
getBuiltinVaListDecl
CreateX86_64ABIBuiltinVaListDecl
VaListTagDecl = TagA
indirectly call getBuiltinVaListDecl
CreateX86_64ABIBuiltinVaListDecl
VaListTagDecl = TagB
BuiltinVaListDecl = ListB
BuiltinVaListDecl = ListA
Now we have `BuiltinVaListDecl == ListA` and `VaListTagDecl == TagB`.
For x86_64 '__builtin_va_list' and 'struct __va_list_tag *' are
compatible because '__builtin_va_list' == '__va_list_tag[1]'. But
because we have unrelated decls for VaListDecl and VaListTagDecl the
types are considered incompatible as we are comparing type pointers.
Fix the error by creating `BuiltinVaListDecl` before
`ASTReader::InitializeSema`, so that during
`ASTContext::getBuiltinVaListDecl` ASTReader doesn't try to de-serialize
'__builtin_va_list' and to call `ASTContext::getBuiltinVaListDecl`
again.
rdar://130947515
