[Webkit-unassigned] [Bug 247121] New: StringOperations.cpp test re-defines WTF::StringTypeAdapter implementation, undefined behaviour

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=247121

            Bug ID: 247121
           Summary: StringOperations.cpp test re-defines
                    WTF::StringTypeAdapter implementation, undefined
                    behaviour
           Product: WebKit
           Version: WebKit Nightly Build
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Web Template Framework
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: kkinnunen at apple.com

StringOperations.cpp test re-defines WTF::StringTypeAdapter implementation, undefined behaviour

StringOperations.cpp re-defines the template implementations in order to count the String copies.
This is undefined behaviour. Two different compilation units linked to same binary cannot have two different implementations for the same name symbol.

The linker knows of two different implementations by the same name, and may do whatever.

Consider:

// header.h
inline int myFunc()
{
  WTF_STRINGTYPEADAPTER_COPIED_WTF_STRING(); 
  return 1;
}

// impl1.cpp:
  #define WTF_STRINGTYPEADAPTER_COPIED_WTF_STRING() (void())
  #include "header.h"
  void call1() {
      myFunc();
  }

// impl2.cpp:
  #define WTF_STRINGTYPEADAPTER_COPIED_WTF_STRING() printf("kimmo")
  #include "header.h"
  void call2() {
    myFunc();
  }


// main.cpp
  void call1();
  void call2();
  int main() {
    call1();
    call2();
    return 0;
  }

c++ impl1.cpp impl2.cpp main.cpp -o my-undefined

It's unclear what the app does.

Currently, all invocations of TestWTF seem to use the test-overridden hack of the implementation.

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