From cdf4f3055e964bb585f294cf77cb549ead82783f Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Mon, 18 Dec 2017 20:11:54 +0000
Subject: Vendor import of compiler-rt trunk r321017:
 https://llvm.org/svn/llvm-project/compiler-rt/trunk@321017

---
 lib/fuzzer/FuzzerExtFunctionsWeak.cpp | 54 +++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 lib/fuzzer/FuzzerExtFunctionsWeak.cpp

(limited to 'lib/fuzzer/FuzzerExtFunctionsWeak.cpp')

diff --git a/lib/fuzzer/FuzzerExtFunctionsWeak.cpp b/lib/fuzzer/FuzzerExtFunctionsWeak.cpp
new file mode 100644
index 000000000000..5a90723986af
--- /dev/null
+++ b/lib/fuzzer/FuzzerExtFunctionsWeak.cpp
@@ -0,0 +1,54 @@
+//===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Implementation for Linux. This relies on the linker's support for weak
+// symbols. We don't use this approach on Apple platforms because it requires
+// clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
+// weak symbols to be undefined. That is a complication we don't want to expose
+// to clients right now.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FUCHSIA
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+
+extern "C" {
+// Declare these symbols as weak to allow them to be optionally defined.
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  __attribute__((weak)) RETURN_TYPE NAME FUNC_SIG
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+using namespace fuzzer;
+
+static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) {
+  if (FnPtr == nullptr && WarnIfMissing) {
+    Printf("WARNING: Failed to find function \"%s\".\n", FnName);
+  }
+}
+
+namespace fuzzer {
+
+ExternalFunctions::ExternalFunctions() {
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  this->NAME = ::NAME;                                                         \
+  CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)),    \
+             #NAME, WARN);
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_LINUX || LIBFUZZER_NETBSD
-- 
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