1872197 - [hazards] calls to lambda functions can be aliased

Status: NEW

(Core :: JavaScript: GC, defect, P3)

Description

[Steve Fink [:sfink] [:s:]]

template <typename Function>
void Call(Function&& f) {
  f();
}
.
.
.
void function_pointers() {
  Call([]() { printf("First lambda\n"): });
  Call([]() { printf("Second lambda\n"): });
}

There are two specialized instances of the Call function here, which sixgill distinguishes, but the invocations of f within the two look identical in the sixgill output. It's not a fundamental problem; the information to distinguish them is present. But both look like source.cpp:void function_pointers()::<lambda()> where source.cpp is the filename, and function_pointers() is the name of the function where the lambdas syntactically appear.

The specialized Call instances have names like:

source.cpp:void Call1(_Z17function_pointersv::__lambda0&&) [with Function = function_pointers()::<lambda()>]
source.cpp:void Call2(_Z27annotated_function_pointersv::__lambda1&&) [with Function = annotated_function_pointers()::<lambda()>]

which shows that the compiler is numbering the lambdas, which is what we want. But the function-scoped and numbered names of the lambdas are not used for the call within the body of the templatized function.

Comment 1

[Steve Fink [:sfink] [:s:]]

This is using gcc's builtin mechanism for fetching the name of a function, so it's not a simple matter of adding smarts to sixgill. It may require detecting and customizing the function name generation for lambda calls.