[Statepoints] Support for "patchable" statepoints.

Summary:
This change adds two new parameters to the statepoint intrinsic, `i64 id`
and `i32 num_patch_bytes`.  `id` gets propagated to the ID field
in the generated StackMap section.  If the `num_patch_bytes` is
non-zero then the statepoint is lowered to `num_patch_bytes` bytes of
nops instead of a call (the spill and reload code remains unchanged).
A non-zero `num_patch_bytes` is useful in situations where a language
runtime requires complete control over how a call is lowered.

This change brings statepoints one step closer to patchpoints.  With
some additional work (that is not part of this patch) it should be
possible to get rid of `TargetOpcode::STATEPOINT` altogether.

PlaceSafepoints generates `statepoint` wrappers with `id` set to
`0xABCDEF00` (the old default value for the ID reported in the stackmap)
and `num_patch_bytes` set to `0`.  This can be made more sophisticated
later.

Reviewers: reames, pgavlin, swaroop.sridhar, AndyAyers

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9546

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237214 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 27 deletions

diff --git a/lib/IR/IRBuilder.cpp b/lib/IR/IRBuilder.cpp
index 87fca8c8610..a0b61494e26 100644
--- a/lib/IR/IRBuilder.cpp
+++ b/lib/IR/IRBuilder.cpp
@@ -245,12 +245,13 @@ CallInst *IRBuilderBase::CreateMaskedIntrinsic(unsigned Id,
   return createCallHelper(TheFn, Ops, this, Name);
 }
 
-static std::vector<Value *> getStatepointArgs(IRBuilderBase &B,
-                                              Value *ActualCallee,
-                                              ArrayRef<Value *> CallArgs,
-                                              ArrayRef<Value *> DeoptArgs,
-                                              ArrayRef<Value *> GCArgs) {
+static std::vector<Value *>
+getStatepointArgs(IRBuilderBase &B, uint64_t ID, uint32_t NumPatchBytes,
+                  Value *ActualCallee, ArrayRef<Value *> CallArgs,
+                  ArrayRef<Value *> DeoptArgs, ArrayRef<Value *> GCArgs) {
   std::vector<Value *> Args;
+  Args.push_back(B.getInt64(ID));
+  Args.push_back(B.getInt32(NumPatchBytes));
   Args.push_back(ActualCallee);
   Args.push_back(B.getInt32(CallArgs.size()));
   Args.push_back(B.getInt32((unsigned)StatepointFlags::None));
@@ -263,11 +264,10 @@ static std::vector<Value *> getStatepointArgs(IRBuilderBase &B,
   return Args;
 }
 
-CallInst *IRBuilderBase::CreateGCStatepointCall(Value *ActualCallee,
-                                                ArrayRef<Value *> CallArgs,
-                                                ArrayRef<Value *> DeoptArgs,
-                                                ArrayRef<Value *> GCArgs,
-                                                const Twine &Name) {
+CallInst *IRBuilderBase::CreateGCStatepointCall(
+    uint64_t ID, uint32_t NumPatchBytes, Value *ActualCallee,
+    ArrayRef<Value *> CallArgs, ArrayRef<Value *> DeoptArgs,
+    ArrayRef<Value *> GCArgs, const Twine &Name) {
   // Extract out the type of the callee.
   PointerType *FuncPtrType = cast<PointerType>(ActualCallee->getType());
   assert(isa<FunctionType>(FuncPtrType->getElementType()) &&
@@ -280,25 +280,25 @@ CallInst *IRBuilderBase::CreateGCStatepointCall(Value *ActualCallee,
     Intrinsic::getDeclaration(M, Intrinsic::experimental_gc_statepoint,
                               ArgTypes);
 
-  std::vector<llvm::Value *> Args =
-      getStatepointArgs(*this, ActualCallee, CallArgs, DeoptArgs, GCArgs);
+  std::vector<llvm::Value *> Args = getStatepointArgs(
+      *this, ID, NumPatchBytes, ActualCallee, CallArgs, DeoptArgs, GCArgs);
   return createCallHelper(FnStatepoint, Args, this, Name);
 }
 
-CallInst *IRBuilderBase::CreateGCStatepointCall(Value *ActualCallee,
-                                                ArrayRef<Use> CallArgs,
-                                                ArrayRef<Value *> DeoptArgs,
-                                                ArrayRef<Value *> GCArgs,
-                                                const Twine &Name) {
+CallInst *IRBuilderBase::CreateGCStatepointCall(
+    uint64_t ID, uint32_t NumPatchBytes, Value *ActualCallee,
+    ArrayRef<Use> CallArgs, ArrayRef<Value *> DeoptArgs,
+    ArrayRef<Value *> GCArgs, const Twine &Name) {
   std::vector<Value *> VCallArgs;
   for (auto &U : CallArgs)
     VCallArgs.push_back(U.get());
-  return CreateGCStatepointCall(ActualCallee, VCallArgs, DeoptArgs, GCArgs,
-                                Name);
+  return CreateGCStatepointCall(ID, NumPatchBytes, ActualCallee, VCallArgs,
+                                DeoptArgs, GCArgs, Name);
 }
 
 InvokeInst *IRBuilderBase::CreateGCStatepointInvoke(
-    Value *ActualInvokee, BasicBlock *NormalDest, BasicBlock *UnwindDest,
+    uint64_t ID, uint32_t NumPatchBytes, Value *ActualInvokee,
+    BasicBlock *NormalDest, BasicBlock *UnwindDest,
     ArrayRef<Value *> InvokeArgs, ArrayRef<Value *> DeoptArgs,
     ArrayRef<Value *> GCArgs, const Twine &Name) {
   // Extract out the type of the callee.
@@ -311,21 +311,22 @@ InvokeInst *IRBuilderBase::CreateGCStatepointInvoke(
   Function *FnStatepoint = Intrinsic::getDeclaration(
       M, Intrinsic::experimental_gc_statepoint, {FuncPtrType});
 
-  std::vector<llvm::Value *> Args =
-      getStatepointArgs(*this, ActualInvokee, InvokeArgs, DeoptArgs, GCArgs);
+  std::vector<llvm::Value *> Args = getStatepointArgs(
+      *this, ID, NumPatchBytes, ActualInvokee, InvokeArgs, DeoptArgs, GCArgs);
   return createInvokeHelper(FnStatepoint, NormalDest, UnwindDest, Args, this,
                             Name);
 }
 
 InvokeInst *IRBuilderBase::CreateGCStatepointInvoke(
-    Value *ActualInvokee, BasicBlock *NormalDest, BasicBlock *UnwindDest,
-    ArrayRef<Use> InvokeArgs, ArrayRef<Value *> DeoptArgs,
-    ArrayRef<Value *> GCArgs, const Twine &Name) {
+    uint64_t ID, uint32_t NumPatchBytes, Value *ActualInvokee,
+    BasicBlock *NormalDest, BasicBlock *UnwindDest, ArrayRef<Use> InvokeArgs,
+    ArrayRef<Value *> DeoptArgs, ArrayRef<Value *> GCArgs, const Twine &Name) {
   std::vector<Value *> VCallArgs;
   for (auto &U : InvokeArgs)
     VCallArgs.push_back(U.get());
-  return CreateGCStatepointInvoke(ActualInvokee, NormalDest, UnwindDest,
-                                  VCallArgs, DeoptArgs, GCArgs, Name);
+  return CreateGCStatepointInvoke(ID, NumPatchBytes, ActualInvokee, NormalDest,
+                                  UnwindDest, VCallArgs, DeoptArgs, GCArgs,
+                                  Name);
 }
 
 CallInst *IRBuilderBase::CreateGCResult(Instruction *Statepoint,