#419 E2K compilation fix for Linux 7-Zip 23.01

[Ramil Sattarov]

Fixed build linux 7-Zip 23.01 on E2K (MCST Elbrus 2000 architecture).

• added initial support of e2k arch
• used compiler built-in functions to get arch and CPU name
• added temporary workaround for mcst-lcc compiler (don't support #pragma message)

[Igor Pavlov]

I suppose that

__builtin_cpu_name
__builtin_cpu_arch

will not work with clang.
So we must use also __LCC__ check for these calls.
I'll fix #pragma message and another problems.
Thanks.

[Ramil Sattarov]

Thanks for your comment, I almost forgot about clang (this compiler has recently appeared on the Elbrus platform).

[Igor Pavlov]

What exact possible output strings of __builtin_cpu_arch()?
Are there any docs for this function?
Does it read some registers from processor?

[Ramil Sattarov]

Possible output strings of const char* __builtin_cpu_arch (void) is:
elbrus-v1, elbrus-v2, elbrus-v3, elbrus-v4, elbrus-v5 and elbrus-v6.
The documentation for the mcst-lcc compiler is currently supplied only with the compiler itself.
This function (as const char* __builtin_cpu_name (void) function) is designed to work in run-time, so it takes data from the processor registers.

[Igor Pavlov]

please check also -m32 modes of clang and lcc:
lcc doesn't use __ILP32__ by some reason, as another compilers.
So we need more checks:
CpuArch.h:

#if  defined(__e2k__)
  #define MY_CPU_E2K
  #if defined(__ILP32__) || defined(__SIZEOF_POINTER__) && (__SIZEOF_POINTER__ == 4)
    #define MY_CPU_NAME "e2k-32"
    #define MY_CPU_SIZEOF_POINTER 4
  #else
    #define MY_CPU_NAME "e2k"
    #if defined(__LP64__) || defined(__SIZEOF_POINTER__) && (__SIZEOF_POINTER__ == 8)
      #define MY_CPU_SIZEOF_POINTER 8
    #endif
  #endif
  #define MY_CPU_64BIT
#endif

[Ramil Sattarov]

Both clang and mcst-lcc use __ptr32__ and __ptr64__ respectively.
Also clang has standard macros as _ILP32, __ILP32__and _LP64,__LP64__.
So, __ptr32__ macro will be enough to check.

A new workaround has also been added in patch for mcst-lcc compiler < 1.26.10 (don't support __attribute__((optimize("no-tree-vectorize"))))

[Igor Pavlov]

__ptr32__ is not good, because gcc doesn't use __ptr32__.
And I try to get some unification, where the code works same way in both gcc and clang for any platform.
So __SIZEOF_POINTER__ check looks better for me.

[Ramil Sattarov]

Yeap, good idea, both compilers use this macro. So we can check only it.

#if  defined(__e2k__)
  #define MY_CPU_E2K
  #if defined(__SIZEOF_POINTER__) && (__SIZEOF_POINTER__ == 4)
    #define MY_CPU_NAME "e2k-ptr32"
    #define MY_CPU_SIZEOF_POINTER 4
  #else
    #define MY_CPU_NAME "e2k"
    #define MY_CPU_SIZEOF_POINTER 8
  #endif
  #define MY_CPU_64BIT
#endif

"e2k-32" is not quite the correct name, since -mptr32 is not a 32—bit mode, like i386 or SPARC V8. This is a 64-bit mode with 32-bit pointers, as in x32 ABI for x86-64. Therefore, I suggest calling it "e2k-ptr32" above, so that there is no confusion and misunderstanding.

There is no such thing as a "32-bit Elbrus". The base registers are always 64-bit, capable of being decomposed into 2 halves or combined into 2 pieces (for v5+).