src/llvm-gc-interface-passes.h

@@ -361,6 +361,7 @@ struct LateLowerGCFrame:  private JuliaPassContext {
     void PlaceGCFrameReset(State &S, unsigned R, unsigned MinColorRoot, ArrayRef<int> Colors, Value *GCFrame, Instruction *InsertBefore);
     void PlaceRootsAndUpdateCalls(ArrayRef<int> Colors, int PreAssignedColors, State &S, std::map<Value *, std::pair<int, int>>);
     void CleanupWriteBarriers(Function &F, State *S, const SmallVector<CallInst*, 0> &WriteBarriers, bool *CFGModified);
+    void CleanupGCPreserve(Function &F, CallInst *CI, Value *callee, Type *T_size);
     bool CleanupIR(Function &F, State *S, bool *CFGModified);
     void NoteUseChain(State &S, BBState &BBS, User *TheUser);
     SmallVector<int, 1> GetPHIRefinements(PHINode *phi, State &S);

src/llvm-late-gc-lowering-mmtk.cpp

@@ -2,6 +2,52 @@
 
 #include "llvm-gc-interface-passes.h"
 
+void LateLowerGCFrame::CleanupGCPreserve(Function &F, CallInst *CI, Value *callee, Type *T_size) {
+    if (callee == gc_preserve_begin_func) {
+        // Initialize an IR builder.
+        IRBuilder<> builder(CI);
+
+        builder.SetCurrentDebugLocation(CI->getDebugLoc());
+        size_t nargs = 0;
+        State S2(F);
+
+        std::vector<Value*> args;
+        for (Use &U : CI->args()) {
+            Value *V = U;
+            if (isa<Constant>(V))
+                continue;
+            if (isa<PointerType>(V->getType())) {
+                if (isSpecialPtr(V->getType())) {
+                    int Num = Number(S2, V);
+                    if (Num >= 0) {
+                        nargs++;
+                        Value *Val = GetPtrForNumber(S2, Num, CI);
+                        args.push_back(Val);
+                    }
+                }
+            } else {
+                auto Nums = NumberAll(S2, V);
+                for (int Num : Nums) {
+                    if (Num < 0)
+                        continue;
+                    Value *Val = GetPtrForNumber(S2, Num, CI);
+                    args.push_back(Val);
+                    nargs++;
+                }
+            }
+        }
+        args.insert(args.begin(), ConstantInt::get(T_size, nargs));
+
+        ArrayRef<Value*> args_llvm = ArrayRef<Value*>(args);
+        builder.CreateCall(getOrDeclare(jl_well_known::GCPreserveBeginHook), args_llvm );
+    } else if (callee == gc_preserve_end_func) {
+        // Initialize an IR builder.
+        IRBuilder<> builder(CI);
+        builder.SetCurrentDebugLocation(CI->getDebugLoc());
+        builder.CreateCall(getOrDeclare(jl_well_known::GCPreserveEndHook), {});
+    }
+}
+
 Value* LateLowerGCFrame::lowerGCAllocBytesLate(CallInst *target, Function &F)
 {
     assert(target->arg_size() == 3);

src/llvm-late-gc-lowering-stock.cpp

@@ -2,6 +2,10 @@
 
 #include "llvm-gc-interface-passes.h"
 
+void LateLowerGCFrame::CleanupGCPreserve(Function &F, CallInst *CI, Value *callee, Type *T_size) {
+    // Do nothing for the stock GC
+}
+
 Value* LateLowerGCFrame::lowerGCAllocBytesLate(CallInst *target, Function &F)
 {
     // Do nothing for the stock GC