1 files changed, 78 insertions, 0 deletions
diff --git a/src/backend/jit/llvm/llvmjit_wrap.cpp b/src/backend/jit/llvm/llvmjit_wrap.cpp
new file mode 100644
index 0000000..692483d
--- /dev/null
+++ b/src/backend/jit/llvm/llvmjit_wrap.cpp
@@ -0,0 +1,78 @@
+/*-------------------------------------------------------------------------
+ *
+ * llvmjit_wrap.cpp
+ *	  Parts of the LLVM interface not (yet) exposed to C.
+ *
+ * Copyright (c) 2016-2021, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  src/backend/lib/llvm/llvmjit_wrap.cpp
+ *
+ *-------------------------------------------------------------------------
+ */
+
+extern "C"
+{
+#include "postgres.h"
+}
+
+#include <llvm-c/Core.h>
+
+/* Avoid macro clash with LLVM's C++ headers */
+#undef Min
+
+#include <llvm/IR/Attributes.h>
+#include <llvm/IR/Function.h>
+#include <llvm/MC/SubtargetFeature.h>
+#include <llvm/Support/Host.h>
+
+#include "jit/llvmjit.h"
+
+
+/*
+ * C-API extensions.
+ */
+#if defined(HAVE_DECL_LLVMGETHOSTCPUNAME) && !HAVE_DECL_LLVMGETHOSTCPUNAME
+char *LLVMGetHostCPUName(void) {
+	return strdup(llvm::sys::getHostCPUName().data());
+}
+#endif
+
+
+#if defined(HAVE_DECL_LLVMGETHOSTCPUFEATURES) && !HAVE_DECL_LLVMGETHOSTCPUFEATURES
+char *LLVMGetHostCPUFeatures(void) {
+	llvm::SubtargetFeatures Features;
+	llvm::StringMap<bool> HostFeatures;
+
+	if (llvm::sys::getHostCPUFeatures(HostFeatures))
+		for (auto &F : HostFeatures)
+			Features.AddFeature(F.first(), F.second);
+
+	return strdup(Features.getString().c_str());
+}
+#endif
+
+/*
+ * Like LLVM's LLVMGetAttributeCountAtIndex(), works around a bug in LLVM 3.9.
+ *
+ * In LLVM <= 3.9, LLVMGetAttributeCountAtIndex() segfaults if there are no
+ * attributes at an index (fixed in LLVM commit ce9bb1097dc2).
+ */
+unsigned
+LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx)
+{
+	/*
+	 * This is more expensive, so only do when using a problematic LLVM
+	 * version.
+	 */
+#if LLVM_VERSION_MAJOR < 4
+	if (!llvm::unwrap<llvm::Function>(F)->getAttributes().hasAttributes(Idx))
+		return 0;
+#endif
+
+	/*
+	 * There is no nice public API to determine the count nicely, so just
+	 * always fall back to LLVM's C API.
+	 */
+	return LLVMGetAttributeCountAtIndex(F, Idx);
+}