Merge "Update aosp/master LLVM for rebase to r230699."

1 files changed, 298 insertions, 0 deletions

diff --git a/include/llvm/IR/Statepoint.h b/include/llvm/IR/Statepoint.h
new file mode 100644
index 0000000..38720ed
--- /dev/null
+++ b/include/llvm/IR/Statepoint.h
@@ -0,0 +1,298 @@
+//===-- llvm/IR/Statepoint.h - gc.statepoint utilities ------ --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains utility functions and a wrapper class analogous to
+// CallSite for accessing the fields of gc.statepoint, gc.relocate, and
+// gc.result intrinsics
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LLVM_IR_STATEPOINT_H
+#define __LLVM_IR_STATEPOINT_H
+
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+
+class GCRelocateOperands;
+class ImmutableStatepoint;
+
+bool isStatepoint(const ImmutableCallSite &CS);
+bool isStatepoint(const Value *inst);
+bool isStatepoint(const Value &inst);
+
+bool isGCRelocate(const Value *inst);
+bool isGCRelocate(const ImmutableCallSite &CS);
+
+bool isGCResult(const Value *inst);
+bool isGCResult(const ImmutableCallSite &CS);
+
+/// Analogous to CallSiteBase, this provides most of the actual
+/// functionality for Statepoint and ImmutableStatepoint.  It is
+/// templatized to allow easily specializing of const and non-const
+/// concrete subtypes.  This is structured analogous to CallSite
+/// rather than the IntrinsicInst.h helpers since we want to support
+/// invokable statepoints in the near future.
+/// TODO: This does not currently allow the if(Statepoint S = ...)
+///   idiom used with CallSites.  Consider refactoring to support.
+template <typename InstructionTy, typename ValueTy, typename CallSiteTy>
+class StatepointBase {
+  CallSiteTy StatepointCS;
+  void *operator new(size_t, unsigned) = delete;
+  void *operator new(size_t s) = delete;
+
+ protected:
+  explicit StatepointBase(InstructionTy *I) : StatepointCS(I) {
+    assert(isStatepoint(I));
+  }
+  explicit StatepointBase(CallSiteTy CS) : StatepointCS(CS) {
+    assert(isStatepoint(CS));
+  }
+
+ public:
+  typedef typename CallSiteTy::arg_iterator arg_iterator;
+
+  /// Return the underlying CallSite.
+  CallSiteTy getCallSite() {
+    return StatepointCS;
+  }
+
+  /// Return the value actually being called or invoked.
+  ValueTy *actualCallee() {
+    return StatepointCS.getArgument(0);
+  }
+  /// Number of arguments to be passed to the actual callee.
+  int numCallArgs() {
+    return cast<ConstantInt>(StatepointCS.getArgument(1))->getZExtValue();
+  }
+  /// Number of additional arguments excluding those intended
+  /// for garbage collection.
+  int numTotalVMSArgs() {
+    return cast<ConstantInt>(StatepointCS.getArgument(3 + numCallArgs()))->getZExtValue();
+  }
+
+  typename CallSiteTy::arg_iterator call_args_begin() {
+    // 3 = callTarget, #callArgs, flag
+    int Offset = 3;
+    assert(Offset <= (int)StatepointCS.arg_size());
+    return StatepointCS.arg_begin() + Offset;
+  }
+  typename CallSiteTy::arg_iterator call_args_end() {
+    int Offset = 3 + numCallArgs();
+    assert(Offset <= (int)StatepointCS.arg_size());
+    return StatepointCS.arg_begin() + Offset;
+  }
+
+  /// range adapter for call arguments
+  iterator_range<arg_iterator> call_args() {
+    return iterator_range<arg_iterator>(call_args_begin(), call_args_end());
+  }
+
+  typename CallSiteTy::arg_iterator vm_state_begin() {
+    return call_args_end();
+  }
+  typename CallSiteTy::arg_iterator vm_state_end() {
+    int Offset = 3 + numCallArgs() + 1 + numTotalVMSArgs();
+    assert(Offset <= (int)StatepointCS.arg_size());
+    return StatepointCS.arg_begin() + Offset;
+  }
+
+  /// range adapter for vm state arguments
+  iterator_range<arg_iterator> vm_state_args() {
+    return iterator_range<arg_iterator>(vm_state_begin(), vm_state_end());
+  }
+
+  typename CallSiteTy::arg_iterator first_vm_state_stack_begin() {
+    // 6 = numTotalVMSArgs, 1st_objectID, 1st_bci,
+    //     1st_#stack, 1st_#local, 1st_#monitor
+    return vm_state_begin() + 6;
+  }
+
+  typename CallSiteTy::arg_iterator gc_args_begin() {
+    return vm_state_end();
+  }
+  typename CallSiteTy::arg_iterator gc_args_end() {
+    return StatepointCS.arg_end();
+  }
+
+  /// range adapter for gc arguments
+  iterator_range<arg_iterator> gc_args() {
+    return iterator_range<arg_iterator>(gc_args_begin(), gc_args_end());
+  }
+
+  /// Get list of all gc reloactes linked to this statepoint
+  /// May contain several relocations for the same base/derived pair.
+  /// For example this could happen due to relocations on unwinding
+  /// path of invoke.
+  std::vector<GCRelocateOperands> getRelocates(ImmutableStatepoint &IS);
+
+#ifndef NDEBUG
+  /// Asserts if this statepoint is malformed.  Common cases for failure
+  /// include incorrect length prefixes for variable length sections or
+  /// illegal values for parameters.
+  void verify() {
+    assert(numCallArgs() >= 0 &&
+           "number of arguments to actually callee can't be negative");
+
+    // The internal asserts in the iterator accessors do the rest.
+    (void)call_args_begin();
+    (void)call_args_end();
+    (void)vm_state_begin();
+    (void)vm_state_end();
+    (void)gc_args_begin();
+    (void)gc_args_end();
+  }
+#endif
+};
+
+/// A specialization of it's base class for read only access
+/// to a gc.statepoint.
+class ImmutableStatepoint
+    : public StatepointBase<const Instruction, const Value,
+                            ImmutableCallSite> {
+  typedef StatepointBase<const Instruction, const Value, ImmutableCallSite>
+      Base;
+
+public:
+  explicit ImmutableStatepoint(const Instruction *I) : Base(I) {}
+  explicit ImmutableStatepoint(ImmutableCallSite CS) : Base(CS) {}
+};
+
+/// A specialization of it's base class for read-write access
+/// to a gc.statepoint.
+class Statepoint : public StatepointBase<Instruction, Value, CallSite> {
+  typedef StatepointBase<Instruction, Value, CallSite> Base;
+
+public:
+  explicit Statepoint(Instruction *I) : Base(I) {}
+  explicit Statepoint(CallSite CS) : Base(CS) {}
+};
+
+/// Wraps a call to a gc.relocate and provides access to it's operands.
+/// TODO: This should likely be refactored to resememble the wrappers in
+/// InstrinsicInst.h.
+class GCRelocateOperands {
+  ImmutableCallSite RelocateCS;
+
+ public:
+  GCRelocateOperands(const User* U) : RelocateCS(U) {
+    assert(isGCRelocate(U));
+  }
+  GCRelocateOperands(const Instruction *inst) : RelocateCS(inst) {
+    assert(isGCRelocate(inst));
+  }
+  GCRelocateOperands(CallSite CS) : RelocateCS(CS) {
+    assert(isGCRelocate(CS));
+  }
+
+  /// Return true if this relocate is tied to the invoke statepoint.
+  /// This includes relocates which are on the unwinding path.
+  bool isTiedToInvoke() const {
+    const Value *Token = RelocateCS.getArgument(0);
+
+    return isa<ExtractValueInst>(Token) ||
+      isa<InvokeInst>(Token);
+  }
+
+  /// Get enclosed relocate intrinsic
+  ImmutableCallSite getUnderlyingCallSite() {
+    return RelocateCS;
+  }
+
+  /// The statepoint with which this gc.relocate is associated.
+  const Instruction *statepoint() {
+    const Value *token = RelocateCS.getArgument(0);
+
+    // This takes care both of relocates for call statepoints and relocates
+    // on normal path of invoke statepoint.
+    if (!isa<ExtractValueInst>(token)) {
+      return cast<Instruction>(token);
+    }
+
+    // This relocate is on exceptional path of an invoke statepoint
+    const BasicBlock *invokeBB =
+      cast<Instruction>(token)->getParent()->getUniquePredecessor();
+
+    assert(invokeBB && "safepoints should have unique landingpads");
+    assert(invokeBB->getTerminator() && "safepoint block should be well formed");
+    assert(isStatepoint(invokeBB->getTerminator()));
+
+    return invokeBB->getTerminator();
+  }
+  /// The index into the associate statepoint's argument list
+  /// which contains the base pointer of the pointer whose
+  /// relocation this gc.relocate describes.
+  unsigned basePtrIndex() {
+    return cast<ConstantInt>(RelocateCS.getArgument(1))->getZExtValue();
+  }
+  /// The index into the associate statepoint's argument list which
+  /// contains the pointer whose relocation this gc.relocate describes.
+  unsigned derivedPtrIndex() {
+    return cast<ConstantInt>(RelocateCS.getArgument(2))->getZExtValue();
+  }
+  Value *basePtr() {
+    ImmutableCallSite CS(statepoint());
+    return *(CS.arg_begin() + basePtrIndex());
+  }
+  Value *derivedPtr() {
+    ImmutableCallSite CS(statepoint());
+    return *(CS.arg_begin() + derivedPtrIndex());
+  }
+};
+
+template <typename InstructionTy, typename ValueTy, typename CallSiteTy>
+std::vector<GCRelocateOperands>
+  StatepointBase<InstructionTy, ValueTy, CallSiteTy>::
+    getRelocates(ImmutableStatepoint &IS) {
+
+  std::vector<GCRelocateOperands> res;
+
+  ImmutableCallSite StatepointCS = IS.getCallSite();
+
+  // Search for relocated pointers.  Note that working backwards from the
+  // gc_relocates ensures that we only get pairs which are actually relocated
+  // and used after the statepoint.
+  for (const User *U : StatepointCS.getInstruction()->users()) {
+    if (isGCRelocate(U)) {
+      res.push_back(GCRelocateOperands(U));
+    }
+  }
+
+  if (!StatepointCS.isInvoke()) {
+    return res;
+  }
+
+  // We need to scan thorough exceptional relocations if it is invoke statepoint
+  LandingPadInst *LandingPad =
+    cast<InvokeInst>(StatepointCS.getInstruction())->getLandingPadInst();
+
+  // Search for extract value from landingpad instruction to which
+  // gc relocates will be attached
+  for (const User *LandingPadUser : LandingPad->users()) {
+    if (!isa<ExtractValueInst>(LandingPadUser)) {
+      continue;
+    }
+
+    // gc relocates should be attached to this extract value
+    for (const User *U : LandingPadUser->users()) {
+      if (isGCRelocate(U)) {
+        res.push_back(GCRelocateOperands(U));
+      }
+    }
+  }
+  return res;
+}
+
+}
+#endif