[Haiku] Support __float128 for Haiku x86 and x86_64

[kristina]

Summary

This patch addresses a compilation error with clang when running in Haiku being unable to compile code using float128 (throws compilation error such as 'float128 is not supported on this target').

[kallisti5]

Thanks smeenai! Any chance of this one getting into 7.x.x? It's technically a bug fix... I think it's the last major hurdle to Haiku compiling (easily) with clang vs gcc.

[kristina]

Do you mind resubmitting those with context? Also I would suggest asking Tom Stellard as he's in charge of handling cherrypicking patches to go into releases once the major rolls over and I think we're pretty close (?) to 7.0.1.

[js]

lib/Basic/Targets/OSTargets.h

262

This seems weird. Shouldn't by stdlibc++ and not by the compiler?

[js]

lib/Basic/Targets/OSTargets.h

262

+be defined

[kristina]

Linux, Solaris and OpenBSD also define it where appropriate, it depends on the target. This is why it's much easier to review when full context (diff with -U 99999) is provided, and means that it has a much lower change of patch doing something unexpected.

[kallisti5]

Indeed. I agree the _GLIBCXX_USE_FLOAT128 is misplaced there. That comes from config.h in libstdc++. That's working around an issue in Haiku's build (libstdc++ is built by gcc, but then we try and use it with clang later)
I can remove that.

Is the FLOAT128 desireable?

[kristina]

In D53696#1305990, @kallisti5 wrote:

Indeed. I agree the _GLIBCXX_USE_FLOAT128 is misplaced there. That comes from config.h in libstdc++. That's working around an issue in Haiku's build (libstdc++ is built by gcc, but then we try and use it with clang later)
I can remove that.

Is the FLOAT128 desireable?

Sorry I was referring to __FLOAT128__ being standard, the other define shouldn't be there IMO. But then again I'm not an expert on Haiku, __FLOAT128__ seems fine to me, the other change looks more questionable, if anyone is familiar with Haiku internals, please chime in.

[kristina]

Ping. Is the author still around? I'm happy to take over this revision if not, and add __FLOAT128__ but unless someone says _GLIBCXX_USE_FLOAT128 is actually defined by the toolchain, I'll remove that line, it looks like it really shouldn't be defined in the toolchain, but I don't have a Haiku toolchain around so I can't say for sure.

[kallisti5]

sorry, busy weekend. If you find the time feel free :-)

• _GLIBCXX_USE_FLOAT128 can (and should) go
• everything else is valid per the discussions here.

Otherwise i'll pick up in the next few days and add the requested context as well.

[kallisti5]

I don't have permission to update this request, so I created https://reviews.llvm.org/D54901 with the updates recommended.

[kristina]

New revision in D54901.

lib/Basic/Targets/OSTargets.h

     Builder.defineMacro("__HAIKU__");
     Builder.defineMacro("__ELF__");
     DefineStd(Builder, "unix", Opts);
+    if (this->HasFloat128) {
+      Builder.defineMacro("__FLOAT128__");
+      Builder.defineMacro("_GLIBCXX_USE_FLOAT128");
+    }
   }
 
 public:

     this->PtrDiffType = TargetInfo::SignedLong;
     this->ProcessIDType = TargetInfo::SignedLong;
     this->TLSSupported = false;
+    switch (Triple.getArch()) {
+    default:
+      break;
+    case llvm::Triple::x86:
+    case llvm::Triple::x86_64:
+      this->HasFloat128 = true;
+      break;
+    }
   }
 };
 

test/CodeGenCXX/float128-declarations.cpp

 // RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
 // RUN: %clang_cc1 -emit-llvm -triple x86_64-pc-solaris2.11 -std=c++11 \
 // RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
+// RUN: %clang_cc1 -emit-llvm -triple i586-pc-haiku -std=c++11 \
+// RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
+// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-haiku -std=c++11 \
+// RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
 //
 /*  Various contexts where type __float128 can appear. The different check
     prefixes are due to different mangling on X86 and different calling