1 files changed, 55 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/ShadowStackGC.cpp b/contrib/llvm/lib/CodeGen/ShadowStackGC.cpp
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+++ b/contrib/llvm/lib/CodeGen/ShadowStackGC.cpp
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+//===-- ShadowStackGC.cpp - GC support for uncooperative targets ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements lowering for the llvm.gc* intrinsics for targets that do
+// not natively support them (which includes the C backend). Note that the code
+// generated is not quite as efficient as algorithms which generate stack maps
+// to identify roots.
+//
+// This pass implements the code transformation described in this paper:
+//   "Accurate Garbage Collection in an Uncooperative Environment"
+//   Fergus Henderson, ISMM, 2002
+//
+// In runtime/GC/SemiSpace.cpp is a prototype runtime which is compatible with
+// ShadowStackGC.
+//
+// In order to support this particular transformation, all stack roots are
+// coallocated in the stack. This allows a fully target-independent stack map
+// while introducing only minor runtime overhead.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/GCs.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/CodeGen/GCStrategy.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "shadowstackgc"
+
+namespace {
+class ShadowStackGC : public GCStrategy {
+public:
+  ShadowStackGC();
+};
+}
+
+static GCRegistry::Add<ShadowStackGC>
+    X("shadow-stack", "Very portable GC for uncooperative code generators");
+
+void llvm::linkShadowStackGC() {}
+
+ShadowStackGC::ShadowStackGC() {
+  InitRoots = true;
+  CustomRoots = true;
+}