Clang-Format ignores disabled conditional preprocessor blocks

[MarcusJohnson91]

Bugzilla Link	39255
Version	trunk
OS	MacOS X

Extended Description

preprocessor blocks aren't formatted properly at all.

Example:

Before:

#if (defined(UNIX))
#define _FILE_OFFSET_BITS 64
#elif (defined _WIN32)
#define _UNICODE
#endif

After:
#if (defined(UNIX))

define _FILE_OFFSET_BITS 64

#elif (defined _WIN32)
#define _UNICODE
#endif

and let's say we're compiling on a UNIX platform, so the first branch of the preprocessor directive is enabled, but not the second.

Only the enabled block would actually be formatted, the disabled block is completely ignored.

I'm not sure if this is just because the formatter is running after the preprocessor, or if it's a lot deeper than that, and Clang is removing the unavailable preprocessor tokens before anyone else has access to it?

[MarcusJohnson91]

Before:

#if (defined(UNIX))
#define _FILE_OFFSET_BITS 64
#elif (defined _WIN32)
#define _UNICODE
#endif

After:
#if (defined(UNIX))

define _FILE_OFFSET_BITS 64

#elif (defined _WIN32)
#define _UNICODE
#endif

How it should look:
#if (defined(UNIX))

define _FILE_OFFSET_BITS 64

#elif (defined _WIN32)

define _UNICODE

#endif

[owenca]

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