Index: llvm/trunk/include/llvm/CodeGen/GCStrategy.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/GCStrategy.h
+++ llvm/trunk/include/llvm/CodeGen/GCStrategy.h
@@ -50,6 +50,7 @@
 #ifndef LLVM_CODEGEN_GCSTRATEGY_H
 #define LLVM_CODEGEN_GCSTRATEGY_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/CodeGen/GCMetadata.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/Support/Registry.h"
@@ -67,6 +68,10 @@
     friend class GCModuleInfo;
     
   protected:
+    bool UseStatepoints;       /// Uses gc.statepoints as opposed to gc.roots,
+                               /// if set, none of the other options can be
+                               /// anything but their default values.
+
     unsigned NeededSafePoints; ///< Bitmask of required safe points.
     bool CustomReadBarriers;   ///< Default is to insert loads.
     bool CustomWriteBarriers;  ///< Default is to insert stores.
@@ -94,6 +99,22 @@
     /// them. 
     bool customReadBarrier() const { return CustomReadBarriers; }
 
+    /// Returns true if this strategy is expecting the use of gc.statepoints,
+    /// and false otherwise.
+    bool useStatepoints() const { return UseStatepoints; }
+
+    /** @name Statepoint Specific Properties */
+    ///@{
+
+    /// If the value specified can be reliably distinguished, returns true for
+    /// pointers to GC managed locations and false for pointers to non-GC 
+    /// managed locations.  Note a GCStrategy can always return 'None' (i.e. an
+    /// empty optional indicating it can't reliably distinguish.   
+    virtual Optional<bool> isGCManagedPointer(const Value *V) const {
+      return None;
+    }
+    ///@}
+
     /** @name GCRoot Specific Properties
      * These properties and overrides only apply to collector strategies using
      * GCRoot. 
@@ -126,7 +147,9 @@
     bool initializeRoots() const { return InitRoots; }
     
     /// If set, appropriate metadata tables must be emitted by the back-end
-    /// (assembler, JIT, or otherwise). 
+    /// (assembler, JIT, or otherwise). For statepoint, this method is
+    /// currently unsupported.  The stackmap information can be found in the
+    /// StackMap section as described in the documentation.
     bool usesMetadata() const { return UsesMetadata; }
 
     ///@}
Index: llvm/trunk/include/llvm/CodeGen/GCs.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/GCs.h
+++ llvm/trunk/include/llvm/CodeGen/GCs.h
@@ -36,6 +36,8 @@
   /// Creates a shadow stack garbage collector. This collector requires no code
   /// generator support.
   void linkShadowStackGC();
+
+  void linkStatepointExampleGC();
 }
 
 #endif
Index: llvm/trunk/include/llvm/CodeGen/LinkAllCodegenComponents.h
===================================================================
--- llvm/trunk/include/llvm/CodeGen/LinkAllCodegenComponents.h
+++ llvm/trunk/include/llvm/CodeGen/LinkAllCodegenComponents.h
@@ -39,6 +39,7 @@
       llvm::linkOcamlGC();
       llvm::linkErlangGC();
       llvm::linkShadowStackGC();
+      llvm::linkStatepointExampleGC();
 
       (void) llvm::createBURRListDAGScheduler(nullptr,
                                               llvm::CodeGenOpt::Default);
Index: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2294,6 +2294,11 @@
   if (!S.usesMetadata())
     return nullptr;
 
+  assert(!S.useStatepoints() && "statepoints do not currently support custom"
+         " stackmap formats, please see the documentation for a description of"
+         " the default format.  If you really need a custom serialized format,"
+         " please file a bug");
+
   gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
   gcp_map_type::iterator GCPI = GCMap.find(&S);
   if (GCPI != GCMap.end())
Index: llvm/trunk/lib/CodeGen/CMakeLists.txt
===================================================================
--- llvm/trunk/lib/CodeGen/CMakeLists.txt
+++ llvm/trunk/lib/CodeGen/CMakeLists.txt
@@ -104,6 +104,7 @@
   StackSlotColoring.cpp
   StackMapLivenessAnalysis.cpp
   StackMaps.cpp
+  StatepointExampleGC.cpp
   TailDuplication.cpp
   TargetFrameLoweringImpl.cpp
   TargetInstrInfo.cpp
Index: llvm/trunk/lib/CodeGen/GCStrategy.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/GCStrategy.cpp
+++ llvm/trunk/lib/CodeGen/GCStrategy.cpp
@@ -93,6 +93,7 @@
 // -----------------------------------------------------------------------------
 
 GCStrategy::GCStrategy() :
+  UseStatepoints(false),
   NeededSafePoints(0),
   CustomReadBarriers(false),
   CustomWriteBarriers(false),
Index: llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/FunctionLoweringInfo.h"
+#include "llvm/CodeGen/GCStrategy.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/StackMaps.h"
 #include "llvm/IR/CallingConv.h"
@@ -417,6 +418,39 @@
   getIncomingStatepointGCValues(Bases, Ptrs, Relocations,
                                 Statepoint.getCallSite(), Builder);
 
+#ifndef NDEBUG
+  // Check that each of the gc pointer and bases we've gotten out of the
+  // safepoint is something the strategy thinks might be a pointer into the GC
+  // heap.  This is basically just here to help catch errors during statepoint
+  // insertion. TODO: This should actually be in the Verifier, but we can't get
+  // to the GCStrategy from there (yet).
+  if (Builder.GFI) {
+    GCStrategy &S = Builder.GFI->getStrategy();
+    for (const Value *V : Bases) {
+      auto Opt = S.isGCManagedPointer(V);
+      if (Opt.hasValue()) {
+        assert(Opt.getValue() &&
+               "non gc managed base pointer found in statepoint");
+      }
+    }
+    for (const Value *V : Ptrs) {
+      auto Opt = S.isGCManagedPointer(V);
+      if (Opt.hasValue()) {
+        assert(Opt.getValue() &&
+               "non gc managed derived pointer found in statepoint");
+      }
+    }
+    for (const Value *V : Relocations) {
+      auto Opt = S.isGCManagedPointer(V);
+      if (Opt.hasValue()) {
+        assert(Opt.getValue() && "non gc managed pointer relocated");
+      }
+    }
+  }
+#endif
+
+
+
   // Before we actually start lowering (and allocating spill slots for values),
   // reserve any stack slots which we judge to be profitable to reuse for a
   // particular value.  This is purely an optimization over the code below and
@@ -498,6 +532,15 @@
   // This should catch any IR level mistake that's made when constructing or
   // transforming statepoints.
   ISP.verify();
+
+  // Check that the associated GCStrategy expects to encounter statepoints.
+  // TODO: This if should become an assert.  For now, we allow the GCStrategy
+  // to be optional for backwards compatibility.  This will only last a short
+  // period (i.e. a couple of weeks).
+  if (GFI) {
+    assert(GFI->getStrategy().useStatepoints() &&
+           "GCStrategy does not expect to encounter statepoints");
+  }
 #endif
 
 
Index: llvm/trunk/test/CodeGen/X86/statepoint-forward.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/statepoint-forward.ll
+++ llvm/trunk/test/CodeGen/X86/statepoint-forward.ll
@@ -20,7 +20,7 @@
 ;; Forwarding the value of a pointer load is invalid since it may have
 ;; changed at the safepoint.  Forwarding a non-gc pointer value would 
 ;; be valid, but is not currently implemented.
-define i1 @test_load_forward(i32 addrspace(1)* addrspace(1)* %p) {
+define i1 @test_load_forward(i32 addrspace(1)* addrspace(1)* %p) gc "statepoint-example" {
 entry:
   %before = load i32 addrspace(1)* addrspace(1)* %p
   %cmp1 = call i1 @f(i32 addrspace(1)* %before)
@@ -39,7 +39,7 @@
 
 ;; Same as above, but forwarding from a store
 define i1 @test_store_forward(i32 addrspace(1)* addrspace(1)* %p,
-                              i32 addrspace(1)* %v) {
+                              i32 addrspace(1)* %v) gc "statepoint-example" {
 entry:
   %cmp1 = call i1 @f(i32 addrspace(1)* %v)
   call void @llvm.assume(i1 %cmp1)
@@ -67,7 +67,7 @@
 ; that is not itself GC managed.  The GC may have an external mechanism
 ; to know about and update that value at a safepoint.  Note that the 
 ; statepoint does not provide the collector with this root.
-define i1 @test_load_forward_nongc_heap(i32 addrspace(1)** %p) {
+define i1 @test_load_forward_nongc_heap(i32 addrspace(1)** %p) gc "statepoint-example" {
 entry:
   %before = load i32 addrspace(1)** %p
   %cmp1 = call i1 @f(i32 addrspace(1)* %before)
@@ -85,7 +85,7 @@
 
 ;; Same as above, but forwarding from a store
 define i1 @test_store_forward_nongc_heap(i32 addrspace(1)** %p,
-                                         i32 addrspace(1)* %v) {
+                                         i32 addrspace(1)* %v) gc "statepoint-example" {
 entry:
   %cmp1 = call i1 @f(i32 addrspace(1)* %v)
   call void @llvm.assume(i1 %cmp1)
@@ -101,7 +101,6 @@
 ; CHECK-LLC: callq f
 }
 
-
 declare void @llvm.assume(i1)
 declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(void ()*, i32, i32, ...)
 declare i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(i32, i32, i32) #3