[cfe-dev] MS style ASM failure and crash

[JB Feldman]

Hi guys,

I will file a bug report in a little bit (once I get a minimal test case)
but I wanted to ask if anyone understands the problem I'm seeing.

Trying to include ntddk.h and compiling with clang-cl, I get the following
message:

In file included from kbfiltr.c:19:
In file included from ./kbfiltr.h:28:
C:\WINDDK\3790.1830\inc\ddk\wxp\ntddk.h(7149,29) :  error: unexpected type
name
      'KPCR': expected expression
    __asm {  movzx eax, _PCR KPCR.Number  }
                             ^
Assertion failed: End.getPointer() <= EndPtr && "frontend claimed part of a
token?", file ..\..\..\..\..\lib\Target\X86\AsmParser\X86AsmParser.cpp,
line 1481
clang-cl.exe: error: clang frontend command failed with exit code 3 (use -v
to s
ee invocation)

The assertion failure obviously results in a crash.

So my initial guess was some kind of Lexer issue, maybe because of no
semicolon, or... who knows. But then, I rewrote that code to read:

int x = FIELD_OFFSET(KPCR, Number);
__asm { movzx eax, fs:[x] }

Which compiles to the same code, and that actually did work with clang-cl.
Can anyone tell me why one works and the other doesn't? (My guess: MS not
following standard Intel notation spec)

Thanks,
JB
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