Begin LLVM C API integration

src/llvm-c/Config/abi-breaking.h

@@ -0,0 +1,62 @@
+/*===------- llvm/Config/abi-breaking.h - llvm configuration -------*- C -*-===*/
+/*                                                                            */
+/* 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 controls the C++ ABI break introduced in LLVM public header. */
+
+#ifndef LLVM_ABI_BREAKING_CHECKS_H
+#define LLVM_ABI_BREAKING_CHECKS_H
+
+/* Define to enable checks that alter the LLVM C++ ABI */
+#define LLVM_ENABLE_ABI_BREAKING_CHECKS 0
+
+/* Define to enable reverse iteration of unordered llvm containers */
+#define LLVM_ENABLE_REVERSE_ITERATION 0
+
+/* Allow selectively disabling link-time mismatch checking so that header-only
+   ADT content from LLVM can be used without linking libSupport. */
+#if !LLVM_DISABLE_ABI_BREAKING_CHECKS_ENFORCING
+
+// ABI_BREAKING_CHECKS protection: provides link-time failure when clients build
+// mismatch with LLVM
+#if defined(_MSC_VER)
+// Use pragma with MSVC
+#define LLVM_XSTR(s) LLVM_STR(s)
+#define LLVM_STR(s) #s
+#pragma detect_mismatch("LLVM_ENABLE_ABI_BREAKING_CHECKS", LLVM_XSTR(LLVM_ENABLE_ABI_BREAKING_CHECKS))
+#undef LLVM_XSTR
+#undef LLVM_STR
+#elif defined(_WIN32) || defined(__CYGWIN__) // Win32 w/o #pragma detect_mismatch
+// FIXME: Implement checks without weak.
+#elif defined(__cplusplus)
+#if !(defined(_AIX) && defined(__GNUC__) && !defined(__clang__))
+#define LLVM_HIDDEN_VISIBILITY __attribute__ ((visibility("hidden")))
+#else
+// GCC on AIX does not support visibility attributes. Symbols are not
+// exported by default on AIX.
+#define LLVM_HIDDEN_VISIBILITY
+#endif
+namespace llvm {
+#if LLVM_ENABLE_ABI_BREAKING_CHECKS
+extern int EnableABIBreakingChecks;
+LLVM_HIDDEN_VISIBILITY
+__attribute__((weak)) int *VerifyEnableABIBreakingChecks =
+    &EnableABIBreakingChecks;
+#else
+extern int DisableABIBreakingChecks;
+LLVM_HIDDEN_VISIBILITY
+__attribute__((weak)) int *VerifyDisableABIBreakingChecks =
+    &DisableABIBreakingChecks;
+#endif
+}
+#undef LLVM_HIDDEN_VISIBILITY
+#endif // _MSC_VER
+
+#endif // LLVM_DISABLE_ABI_BREAKING_CHECKS_ENFORCING
+
+#endif