Merge pull request rust-lang#180 from ptersilie/frameaddr_notlive

Fold stackmaps into control point during lowering.

Author: ltratt

llvm/lib/Transforms/Yk/StackMaps.cpp

@@ -11,6 +11,7 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/InitializePasses.h"
@@ -99,6 +100,16 @@ class YkStackmaps : public ModulePass {
         // the offset of the stackmap entry will record the instruction after
         // the call, which is where we want to continue after deoptimisation.
         Bldr.SetInsertPoint(I->getNextNode());
+        CallInst &CI = cast<CallInst>(*I);
+        if (!CI.isIndirectCall() &&
+            CI.getCalledFunction()->getName() == YK_NEW_CONTROL_POINT) {
+          assert(isa<IntrinsicInst>(Args.back()) &&
+                 cast<IntrinsicInst>(Args.back())->getIntrinsicID() ==
+                     Intrinsic::frameaddress);
+          // Remove the last live argument which is the frameaddr which we have
+          // no use for and is difficult to remove during tracing.
+          Args.pop_back();
+        }
       }
       Bldr.CreateCall(SMFunc->getFunctionType(), SMFunc,
                       ArrayRef<Value *>(Args));

llvm/lib/YkIR/YkIRWriter.cpp

@@ -4,6 +4,7 @@
 //
 //===-------------------------------------------------------------------===//
 
+#include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
@@ -18,6 +19,7 @@
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Transforms/Yk/ControlPoint.h"
 
 using namespace llvm;
 using namespace std;
@@ -693,7 +695,9 @@ class YkIRWriter {
     for (unsigned OI = 0; OI < I->arg_size(); OI++) {
       serialiseOperand(I, FLCtxt, I->getOperand(OI));
     }
-    if (!I->getCalledFunction()->isDeclaration()) {
+    bool IsCtrlPointCall =
+        I->getCalledFunction()->getName() == YK_NEW_CONTROL_POINT;
+    if (!I->getCalledFunction()->isDeclaration() || IsCtrlPointCall) {
       // The next instruction will be the stackmap entry
       // has_safepoint = 1:
       OutStreamer.emitInt8(1);