Merge rust-lang#58

58: Apply stackmap mappings transitively. r=ltratt a=ptersilie



Co-authored-by: Lukas Diekmann <lukas.diekmann@gmail.com>

Author: bors[bot]

llvm/lib/Target/X86/X86AsmPrinter.cpp

@@ -97,7 +97,17 @@ void processInstructions(
       const MachineOperand Rhs = Instr.getOperand(1);
       assert(Lhs.isReg() && "Is register.");
       assert(Rhs.isReg() && "Is register.");
-      SpillMap[Lhs.getReg()] = Rhs.getReg();
+      if (SpillMap.count(Rhs.getReg()) > 0) {
+        // If the RHS has a mapping, apply the same mapping to the new register.
+        // This means, that stack spills moved into one register and then into
+        // another will continued to be tracked.
+        SpillMap[Lhs.getReg()] = SpillMap[Rhs.getReg()];
+      } else {
+        SpillMap[Lhs.getReg()] = Rhs.getReg();
+      }
+      // YKFIXME: If the `mov` instruction has a killed-flag, remove the
+      // register from the map.
+
       // Reassigning a new value to Lhs means any mappings to Lhs are now void
       // and need to be removed.
       clearRhs(Lhs.getReg(), SpillMap);

llvm/lib/Transforms/Yk/ControlPoint.cpp

@@ -220,10 +220,6 @@ class YkControlPoint : public ModulePass {
     // Replace the call to the dummy control point.
     OldCtrlPointCall->eraseFromParent();
 
-    // Get the result of the control point call. If it returns true, that means
-    // the stopgap interpreter has interpreted a return so we need to return as
-    // well.
-
     // Create the new exit block.
     BasicBlock *ExitBB = BasicBlock::Create(Context, "", Caller);
     Builder.SetInsertPoint(ExitBB);