[clang] [Clang][Xtensa] Add Xtensa target. (PR #118008)

[Eli Friedman via cfe-commits]

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@@ -0,0 +1,62 @@
+//===--- Xtensa.cpp - Implement Xtensa target feature support -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Xtensa TargetInfo objects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Xtensa.h"
+#include "clang/Basic/Builtins.h"
+#include "clang/Basic/MacroBuilder.h"
+#include "clang/Basic/TargetBuiltins.h"
+
+using namespace clang;
+using namespace clang::targets;
+
+void XtensaTargetInfo::getTargetDefines(const LangOptions &Opts,
+                                        MacroBuilder &Builder) const {
+  Builder.defineMacro("__xtensa__");
+  Builder.defineMacro("__XTENSA__");
+  if (BigEndian)
+    Builder.defineMacro("__XTENSA_EB__");
+  else
+    Builder.defineMacro("__XTENSA_EL__");
+  if (HasWindowed)
+    Builder.defineMacro("__XTENSA_WINDOWED_ABI__");
+  else
+    Builder.defineMacro("__XTENSA_CALL0_ABI__");
+  if (!HasFP)
+    Builder.defineMacro("__XTENSA_SOFT_FLOAT__");
+  Builder.defineMacro("__XCHAL_HAVE_BE", BigEndian ? "1" : "0");
+  Builder.defineMacro("__XCHAL_HAVE_DENSITY", HasDensity ? "1" : "0");
----------------
efriedma-quic wrote:

On most targets, if a feature isn't available, the feature macro isn't defined at all.  Defining it to 0 is unusual.

If you need to do it this way for compatibility with existing code, I guess that's okay?

https://github.com/llvm/llvm-project/pull/118008