[AIX][PowerPC] Define __powerpc and __PPC macros

[Jake-Egan]

Summary

This patch defines the macros __powerpc and __PPC on AIX to be consistent with XL for AIX. See: https://www.ibm.com/docs/en/xl-c-and-cpp-aix/13.1.0?topic=macros-related-platform

Note: GCC does not currently define __powerpc and __PPC so users should prefer the __powerpc__ and __PPC__ forms.

[cebowleratibm]

I'd like to see the rationale for adding these forms of the macros in the review and also in the extended commit message. These forms are being added primarily because the AIX XL compiler documented and defined them. The patch itself looks fine.

[nemanjai]

In D108917#2974490, @cebowleratibm wrote:

I'd like to see the rationale for adding these forms of the macros in the review and also in the extended commit message. These forms are being added primarily because the AIX XL compiler documented and defined them. The patch itself looks fine.

If XL only defines this on AIX, so should Clang. They only go into this location if XL defines them on both Linux and AIX.

[cebowleratibm]

The XL compiler only defined this weird form of the macros on AIX, but not on the XL Linux on Power compiler. I think it's preferable that we define these macros only on AIX and in the source/commit messages indicate that we're only doing so for AIX XL C/C++ compatibility. Users should prefer the PPC and powerpc macros.

[Jake-Egan]

Define for AIX only.

[cebowleratibm]

clang/test/Preprocessor/init-ppc.c

525

I suggest adding the negative test for the non AIX target for both PPC andpowerpc

[Jake-Egan]

Add negative test.

[cebowleratibm]

LGTM.

clang/lib/Basic/Targets/PPC.cpp

if (PointerWidth == 64) {
     Builder.defineMacro("__ppc64__");
     Builder.defineMacro("__PPC64__");
   } else if (getTriple().isOSAIX()) {
     // The XL compilers on AIX define _ARCH_PPC64 for both 32 and 64-bit modes.
     Builder.defineMacro("_ARCH_PPC64");
   }
   if (getTriple().isOSAIX()) {
     Builder.defineMacro("__THW_PPC__");
+    // Define __PPC and __powerpc for AIX XL C/C++ compatibility
+    Builder.defineMacro("__PPC");
+    Builder.defineMacro("__powerpc");
   }
 
   // Target properties.
   if (getTriple().getArch() == llvm::Triple::ppc64le ||
       getTriple().getArch() == llvm::Triple::ppcle) {
     Builder.defineMacro("_LITTLE_ENDIAN");
   } else {
     if (!getTriple().isOSNetBSD() &&

clang/test/Preprocessor/init-ppc.c

 // PPC:#define __LONGDOUBLE128 1
 // PPC:#define __LONG_DOUBLE_128__ 1
 // PPC:#define __LONG_LONG_MAX__ 9223372036854775807LL
 // PPC:#define __LONG_MAX__ 2147483647L
 // PPC-NOT:#define __LP64__
 // PPC:#define __NATURAL_ALIGNMENT__ 1
 // PPC:#define __POINTER_WIDTH__ 32
 // PPC:#define __POWERPC__ 1
+// PPC-NOT:#define __PPC 1
 // PPC:#define __PPC__ 1
 // PPC:#define __PTRDIFF_TYPE__ long int
 // PPC:#define __PTRDIFF_WIDTH__ 32
 // PPC:#define __REGISTER_PREFIX__
 // PPC:#define __SCHAR_MAX__ 127
 // PPC:#define __SHRT_MAX__ 32767
 // PPC:#define __SIG_ATOMIC_MAX__ 2147483647
 // PPC:#define __SIG_ATOMIC_WIDTH__ 32

 // PPC:#define __UINT_LEAST8_MAX__ 255
 // PPC:#define __UINT_LEAST8_TYPE__ unsigned char
 // PPC:#define __USER_LABEL_PREFIX__
 // PPC:#define __WCHAR_MAX__ 2147483647
 // PPC:#define __WCHAR_TYPE__ int
 // PPC:#define __WCHAR_WIDTH__ 32
 // PPC:#define __WINT_TYPE__ int
 // PPC:#define __WINT_WIDTH__ 32
+// PPC-NOT:#define __powerpc 1
 // PPC:#define __ppc__ 1
 
 // RUN: %clang_cc1 -E -dM -ffreestanding -triple=powerpc-ibm-aix7.1.0.0 -fno-signed-char < /dev/null | FileCheck -match-full-lines -check-prefix PPC-AIX %s
 //
 // PPC-AIX-NOT:#define __64BIT__ 1
 // PPC-AIX:#define _AIX 1
 // PPC-AIX:#define _ARCH_PPC 1
 // PPC-AIX:#define _ARCH_PPC64 1

 // PPC-AIX:#define __LDBL_MIN_EXP__ (-1021)
 // PPC-AIX:#define __LDBL_MIN__ 2.2250738585072014e-308L
 // PPC-AIX:#define __LONG_LONG_MAX__ 9223372036854775807LL
 // PPC-AIX:#define __LONG_MAX__ 2147483647L
 // PPC-AIX-NOT:#define __LP64__ 1
 // PPC-AIX-NOT:#define __NATURAL_ALIGNMENT__ 1
 // PPC-AIX:#define __POINTER_WIDTH__ 32
 // PPC-AIX:#define __POWERPC__ 1
+// PPC-AIX:#define __PPC 1
 // PPC-AIX:#define __PPC__ 1
 // PPC-AIX:#define __PTRDIFF_TYPE__ long int
 // PPC-AIX:#define __PTRDIFF_WIDTH__ 32
 // PPC-AIX:#define __REGISTER_PREFIX__
 // PPC-AIX:#define __SCHAR_MAX__ 127
 // PPC-AIX:#define __SHRT_MAX__ 32767
 // PPC-AIX:#define __SIG_ATOMIC_MAX__ 2147483647
 // PPC-AIX:#define __SIG_ATOMIC_WIDTH__ 32

 // PPC-AIX:#define __UINT_LEAST8_MAX__ 255
 // PPC-AIX:#define __UINT_LEAST8_TYPE__ unsigned char
 // PPC-AIX:#define __USER_LABEL_PREFIX__
 // PPC-AIX:#define __WCHAR_MAX__ 65535
 // PPC-AIX:#define __WCHAR_TYPE__ unsigned short
 // PPC-AIX:#define __WCHAR_WIDTH__ 16
 // PPC-AIX:#define __WINT_TYPE__ int
 // PPC-AIX:#define __WINT_WIDTH__ 32
+// PPC-AIX:#define __powerpc 1
 // PPC-AIX:#define __powerpc__ 1
 // PPC-AIX:#define __ppc__ 1
 
 // RUN: %clang_cc1 -E -dM -ffreestanding -triple=powerpc-ibm-aix7.3.0.0 < /dev/null | FileCheck -match-full-lines -check-prefix PPC-AIX73 %s
 //
 // PPC-AIX73:#define _AIX32 1
 // PPC-AIX73:#define _AIX41 1
 // PPC-AIX73:#define _AIX43 1