Visual D Privileged instruction

[Rainer Schuetze]

On 16/05/2019 17:28, Alex wrote:
> 0xC0000096: Privileged instruction.
> 
> This happens when I run an app that throws an error inside visual D.
> When I run it on it's own I get the correct error.
> 
> std.file.FileException at std\file.d(449): data.xml: The system cannot find
> the file specified.
> ----------------
> 0x00007FF61625E4B9 in @trusted bool
> std.file.cenforce!(bool).cenforce(bool, scope const(char)[], scope
> const(wchar)*, immutable(char)[], ulong)
> 0x00007FF61624ECB2 in @safe void[] std.file.readImpl(scope
> const(char)[], scope const(wchar)*, ulong)
> 0x00007FF615F8EC0E in std.file.read!string.read at
> X:\dmd2\windows\bin\..\..\src\phobos\std\file.d(313)
> 0x00007FF615F8B083 in D main at main.d(133)
> 
> The problem is that I have to open up a console and run the program in
> it to see this error.
> 
> This only happens with x64 and happens with every single throwing error.
> 
> Is there a bug in the code that handles exceptions for x64 that is
> causing the privileged instruction error?

dmd doesn't use a standard exception handling for x64, but implements a
generic version derived from older posix implementations.

Usually all exceptions or errors are handled by the runtime showing the
stack trace. But when running in a debugger, unhandled exceptions are
not caught by the runtime but the privileged instruction is executed.
This allows analyzing the code at the location of the throw. The
debugger should show you the same callstack as the trace above.

LDC uses (slightly modified) C++ exceptions, so debugger support for
these is better.